Computer outside the LAN connection is inserted through the mainframe as a network interface board (or a PCMCIA card ) is inserted in the notebook computer . The network interface board is also known as communications adapter or network adapter (adapter) or Network Interface Card NIC (Network Interface Card), but now more people are willing to use the simple name "card".
Catalog card functionality briefly card functions Detailed card of the main functions of the following three
A package of data and re-opened
2 link management
(3) encoding and decoding
The genuineness of the identification card
(1) spray tin plate
(2) the quality of the main control chip
(3) The use of SMT SMD components
(4) titanium gold cheat
Considerations in the purchase card
Type of network
Transmission rate
Bus Type
NIC-supported cable interface
Price and brand
other knowledge of the network card wireless network card network card, network card Brand
Intel
Realtek
Broadcom
VIA and SIS
Card functions outlined the card functions Detailed card has the following three
A package of data and re-opened
2 link management
(3) encoding and decoding
The genuineness of the identification card
(1) spray tin plate
(2) the quality of the main control chip
(3) The use of SMT SMD components
(4) titanium gold cheat
Considerations in the purchase card
Type of network
Transmission rate
Bus Type
NIC-supported cable interface
Price and brand
other knowledge of the network card wireless network card network card
Common card brand
Intel
Realtek
Broadcom
VIA and SIS
Edit this paragraph card function briefly card work at the data link layer, network components, the LAN interface to connect computers and transmission media , not only able to match with the physical connection between the LAN transmission medium and electrical signals, but also involved in sending and receiving of the frame, the frame of the package and unpack, MAC , data encoding and decoding, and data caching functionality. Edit this paragraph card features Detailed network card fitted with a processor and memory (including RAM and ROM). Communication between the LAN and the LAN cable or twisted pair serial transmission. The communication between the card and the computer is a parallel transmission through the I / O bus on the computer motherboard . Therefore, an important feature of the network card is serial / parallel conversion. On the network data rate and data rate on the computer bus is not the same, must be equipped with a data cache memory chip in the card . Management network card device driver must install the network card installed in your computer's operating system . This driver will tell the card, should be sent over the LAN from the memory location will be data blocks stored. The network card is also Ethernet protocol. NIC is not independent self-governing unit, because the card itself, with no power but must be inserted in the computer's power supply, and subject to the control of the computer. Network card can be seen as a semi-autonomous unit. When the NIC receives a frame error, it will discard the frame without having to notify the computer that it is inserted. When the network card receives a correct frame, it interrupts to notify the computer and delivered to the network layer in the protocol stack . When the computer you want to send an IP packet, it will be down by the protocol stack to the NIC assembled framing sent to the LAN. With the continuous improvement of the integration, the number of chips on the card continually reduced, although a wide range of all manufacturers card, but its function is much the same. The main function to edit this paragraph, card data, together with the following three 1. data package and re-opened to send on the floor to pay down first and tail, the Ethernet frame. When receiving Ethernet frames stripped of the first and the tail, and then sent to a layer; 2 link management is the CSMA / CD (Carrier Sense Multiple Access with Collision Detection Carrier Sense Multiple Access with the Collision Detection, ) protocol implementation; 3 encoding and decoding, namely the Manchester encoding and decoding . Spray tin plate quality card board edit the genuineness of the identification card of this paragraph below, I will introduce a high-quality network card should have the conditions: (1) generally use the spray tin plate, the NIC sheet is white, while the poor card yellow. (2) the quality of the main control chip main control chip is the most important parts of the card , it often determines the performance of the merits of the network card , so the main control chip used in high-quality card is a mature product on the market. The market a lot of inferior card in order to reduce costs while using the older version of the main control chip, which undoubtedly played a discount to the network card performance. (3) The majority of the SMT chip component quality card In addition to the electrolytic capacitors and high voltage ceramic capacitors, and other resistance vessels most of the more reliable and stable than the plug-in SMT chip components. Inferior card is mostly plug-in, which makes heat dissipation and stability of the network card is not good enough. (4) titanium gold Goldfinger Goldfinger of high-quality card selection of titanium metal production, not only increases its anti-jamming capability and reduce interference with other devices, while Goldfinger's node of the arc-shaped design. Poor quality card they use a non-titanium gold, the node is a right angle turn, affect the performance of signal transmission . Edit this paragraph, the factors to consider in the purchase card to the correct selection of assembly, connections, and set the card is often the prerequisite and necessary condition for correct connectivity of the network. In general, the purchase card to consider the following factors: the type of network is now more popular Ethernet, Token Ring , FDDI network, choose should be based on the type of network to choose the corresponding card. Transfer rate should be based on the bandwidth requirements of the server or workstation, and combined with the physical transmission medium can provide the maximum transfer rate to select the transmission rate of the network card. To Ethernet, for example, the choice of rates have 10Mbps 10/100Mbps, 1000Mbps and even 10Gbps other, but not the rate the higher the more appropriate. For example, a computer connected with 100M transmission speed over twisted-pair configuration 1000M network card is a waste, because at best achieve only 100M of transmission rate. The bus type computer bus slot types: ISA, EISA, VESA, PCI and PCMCIA. Smart card for PCI or E ISA bus is usually on the server , and workstation available PCI or ISA bus ordinary card in a notebook computer with PCMCIA bus card or using a portable parallel interface card. The PC is basically no longer supports ISA connections, so when the purchase card for a PC, do not buy the outdated ISA card, but should be optional PCI card . The cable interface card supported by the NIC to the final with the network connection, so it must have an interface cable through its connection with other computer network equipment. Different network interface for the different network types , the common interface Ethernet RJ-45 interfaces, and thin coaxial cable, BNC connectors and thick coaxial, AUI interface, FDDI interfaces , ATM interfaces. And some network cards in order to apply to a wide range of application environments, provide two or more types of interface, if the card will also provide RJ-45, BNC interface or AUI interface. (A) RJ-45 interface : This is the most common type of card, but also the most widely used type of interface card, mainly due to the popularity of the twisted-pair Ethernet applications. This RJ-45 connector type of card is used in Ethernet twisted pair transmission medium, its interface is similar to a telephone interface RJ-11 RJ-45 is the 8-cell lines, and telephone The line interface is a 4-core, and usually only take two core lines (ISDN phone line connected to the 4-wire). Preliminary judgment by the two light colors work state of the network card on the card also comes with two status indicator light . (B) BNC Interface: This interface card used in Ethernet or Token Ring using thin coaxial cable as the transmission medium , the network card of this type of interface is rare, mainly because with a thin coaxial cable as a transmission The media network is relatively small. (C) AUI interface : this interface is the type of card pairs used in Ethernet or Token Ring to thick coaxial cable as the transmission medium of this type of interface card is rare. (D) The FDDI interface: This interface card is adapted to FDDI, ( Fiber Distributed Data Interface) network, this network with 100Mbps of bandwidth, but it uses the transmission medium is optical fiber, so this FDDI interface card interface optical interface. With the emergence of Fast Ethernet , it's speed superiority no longer exists, but it must be expensive optical fiber as the transmission medium's shortcomings and has not changed so very rare. (E) The ATM interface: This interface type of the card is used in ATM ( ATM ) fiber (or twisted pair) network. It provides the physical transmission speed up to 155Mbps price and brand at different rates, different brand of card prices vary greatly. Edit this paragraph, other knowledge of the card (1) NIC: Command Ping command to determine the network failure is a very useful tool to test the network connection status and information packet to send and receive status, is the most commonly used network testing commands. Ping to the target host ( address ) send an echo request packet after receipt of the request requires the target host to reply, in order to determine whether the network response time and native Unicom with the target host (address) . If the Ping is unsuccessful, you can predict the failure to appear in the following areas: cable failures, network adapter configuration is not correct, the IP address is not correct. Ping the success of the network still does not work then the problem probably lies in the software configuration of the network system , the Ping success can only guarantee a connected physical path between the machine and the target host . Command format : ping the IP address or host name [-t] [-a] [-n count] [-l size] the meaning of the parameters : -t keep to the target host to send data ; -a IP address format to display the target The network address of the host; -n count to specify the Ping how many times the specific number of times specified by the count; -size the size of the specified packet sent to the target host. For example, when your machine can not access the Internet, first of all, you want to confirm whether the failure of the local LAN. Assumes that the LAN proxy server IP address is 202.168.0.1, you can use Ping to avoid 202.168.0.1 command to see whether the machine Unicom and proxy servers. In another example, the commonly used commands to test the machine's network card is installed correctly is to ping 127.0.0.1 . Tracert command is used to display the packet arrives at the path that the target host, and display the time of each node is reached. Command functions with the Ping similar, but the information it obtained in much greater detail than the Ping command, which path packets are taking all the node's IP and the time it takes are displayed. This command is more suitable for large networks. The command format : the tracert IP address or host name [-d] [-h maximumhops-the j host_list] [-w timeout] parameter meanings : -d does not resolve the name of the target host ; -h maximum_hops, specify the search to the target address number of hops; - j host_list in accordance with the release of source routing list of hosts in the address ; -w timeout Specifies the timeout interval, the program default time unit is milliseconds . If we are behind the Tracert command with some parameters, but also can detect other more detailed information, such as using the parameter-d can specify procedures to track the host path information, but also to resolve the domain name of the target host. Netstat command that can help network administrators to understand the overall usage of the network. It can display the current active network connection details, such as network connections, routing tables and network interface information, statistics, total of which network connections are running. Command parameter, the command displays the status of the use of all agreements, these agreements include the TCP protocol, UDP protocol and IP protocol, and also can select a specific agreement and to view its specific information, but also displays all the host port number and the current host detailed routing information. Command format: netstat [-r] [-s] [-n] [-a] the meaning of the parameters: -r displays the contents of the routing table of the machine; -s display for each protocol in use (including the TCP protocol, UDP protocol, figures in tabular form, the IP protocol); -n Displays addresses and port; -a display all host port number. Winipcfg command in the form of the window shows the IP protocol configuration information, the command to display the physical address of the network adapter , the host's IP address, subnet mask and default gateway , host name, DNS server , node type can also view other relevant information. Which network adapter physical address is useful in the detection of network errors. Format of the command: winipcfg, [/?] [/ All] parameter meaning: / all Displays all the IP address configuration information; / batch file] command results written to the specified file; / renew_ all retry all network adapters; / release_all release all network adapters; / renew N-reset network adapter N; / release N Release Network Adapter N. (2) NIC: LED indicator In general, each card has a LED (Light Emitting Diode Light Emitting Diode) indicator, used to represent the different state of the network card to facilitate we view the network card is working properly. The typical LED indicators Link / Act, Full Power and Associates. Link / Act that a connection is active, Full whether full-duplex (Full Duplex), and Power is the power instructions. (3) NIC: the main chip card controller chip is the core component of the network card, the performance of a network card is good or bad, to see the quality of this chip. NIC's main control chip is generally using a 3.3V low-power design, 0.35μm chip technology, which allows it to quickly calculate the data flowing through the network card, so as to reduce the burden on the CPU. The following is commonly used in LAN controller chip. 1, the Realtek 8201BL: a common motherboard integrated network chip (also known as PHY network chip). PHY chip refers to the network control chip operation by the processor or the Southbridge chip processing, in order to simplify the circuit design, thereby reducing costs. 2, the Realtek 8139C / D: is the most used card one. 8139D major increase in power management features, while others are basically no different from 8139C chip. Chip supports 10M/100Mbps. 3, lntel Pro/100VE: lntel company's entry-level networking chips. 4, nForce MCP NVIDIA/3Com: nForce2 built-in function of two sets of network chips, the Realtek 8210BL PHY network chip and Broabcom AC101L PHY network chip. 5,3 Com 905C: C support 10/100Mbps speed. SiS900: originally a single network control chip, but is now integrated into the Southbridge chip. Support 100Mbps. (4) NIC: remote wake-up function remote wake technology (WOL, the Wake-on-LAN) is a network card in conjunction with other hardware and software, through the LAN remote boot of a technology, whether it be access to the computer how far away from us. in what position, as long as it is in the same LAN are able to start at any time. This technique is ideal for remote network management environment, if such a request should pay attention to the optional network card has this capability. Can be remotely wake up the computer hardware have certain requirements, mainly on the card, motherboard and power supply. (a) NIC : ability to achieve the remote wake-up, including one of the most important part is to support WOL network card. Remote wake up the computer's NIC must support WOL, used to wake up other computers on the network card you do not have to support WOL. In addition, when multiple network cards installed in a computer, only one of the one set as a remote wake. (b) Motherboard : must also support remote wake-up, through the "Power Management Setup" menu, see the CMOS has a "Wake on LAN" to confirm. In addition, the motherboard supports remote wake-up usually has a dedicated 3-wire outlet to give the card power supply (PCI 2.1 standard). Motherboards now usually support the PCI 2.2 standard, can be directly through the PCI slot NIC +3.3 V Standby power, if not connect the WOL power cord can achieve remote wake-up, therefore, may no longer provide the 3-pin socket. Motherboard whether support PCI2.2 standard, and available through the "Power Management Setup" menu of the View CMOS "Wake on PCI Card" to confirm. c power supply : Ruoyu remote wake-up computer installation must comply with the ATX 2.01 standard ATX power supply , +5 V Standby current is at least more than 600 mA . NIC is not installed successfully how to solve? The general reason may be that the NIC driver does not interrupt number or I / O value does not and the card itself, hardware failure caused by the network card is not installed successfully. You can for testing according to the following steps : (1) Such cards are generally factory set default value , these values include "interrupt" (IR Q value) is "3", the "I / O address range (ie, I / O) 300-31F ", you can double-click the name of the card here, to detect whether these values modified, if not, please correct the need to restart your computer (corrected). (2) If the value of the above has convinced is correct, the card still does not work properly (ie, in front of a yellow exclamation point), please re-enter the Device Manager tab, expand the "Ports (COM LPT) If there are "Communications Port (COM2)" word exists, you also need to shield the COM2 port. Default COM2 port will occupy the interrupt number 3, the initial value of the range of network card NE2000 compatible conflict, so that the card does not work. Operation, please restart the computer when the computer restarts, follow the prompts to press on the keyboard the "Del" key to enter the CMOS, then INTERGRATED PERIPHER A LS, select the "Onboard Serial Port 2", then on the keyboard the "Pae, Up" key to re-election as the "Disable" (disabled) CMOS, press the "Esc" key to return the main menu, press the F10 key to save the changes made after the restart the computer. (3) If that does not, then it is recommended that in the card name, right-click and choose "delete", and then restart the computer, and then re-strict steps to add this card. (4) The next try, you can replace what card slot to try. (5) If it still does not work, then either of this card is not NE2000 compatible series, either the network card itself is faulty. (6) Of course, if someone changes the sheets of card number of the interrupt and I / O values that you use the default value of natural is not enough, therefore, to be safe, you can find the complete installation of this card set disk run inside the setup program, check its default value, if different, and then again under the new value to be modified; If you run the setup program, the system prompts you to find the relevant card, your card is not plugged in or where the slot or the card itself has a hardware failure. Edit this paragraph Wireless LAN Wireless LAN definition of the so-called wireless network , is the use of wireless local area network (WLAN) radio waves as the information transmission medium, very similar to the use of wired network, the biggest difference is the transmission medium of the different, the use of radio technology instead of cable and wired network backup for each other, but unfortunately too slow. The wireless card terminal wireless network equipment, wireless terminal equipment for Internet use of the wireless coverage of the wireless LAN through a wireless connection network. Specifically, the wireless card is to make your computer can take advantage of wireless Internet device, but with the wireless card is also need for a connected wireless network if you are at home or the location of a wireless router or wireless AP (the AccessPoint wireless access point) coverage, you can connect to a wireless network through the wireless network card wireless Internet access. Microwave radio frequency technology is the wireless card works, notebook WIFI , GPRS , CDMA several wireless data transmission mode to the Internet, the latter two by China Mobile and China Unicom, the former Telecom or Netcom has been involved in, but do not more than the main WIFI base station has access to the Internet (in fact, is WIFI routers , etc.) and laptop with WIFI card. Say that the basic concept is similar to data via wireless transmission. Wireless Internet access, follow the 802.1q standard wireless access point signal, the wireless card to receive and send data via wireless transmission. According to the IEEE802.11 protocol, the wireless LAN card into the Media Access Control (MAC) layer and physical layer (PHY Layer) between the two, but also defines a media access control - physical (MAC-PHY) sublayer (Sublayers) . The MAC layer provides the interface between the host and the physical layer, and management of external memory , it corresponds to the NIC unit with wireless LAN hardware. The physical layer specific radio signal reception and emission, corresponds to the spread spectrum communication equipment with wireless LAN hardware. The physical layer provides packing and unpacking of the idle channel estimation CCA information to the MAC layer, in order to decide whether to send a signal through the control of the MAC layer wireless network CCSMA / CA protocol, the MAC-PHY sublayer of the data, the necessary control information on the front of the packet. IEEE802.11 protocol, physical layer must have at least one idle channel estimation method of the CCA signal. The wireless card works as follows: When the physical layer signal is received and confirmed to be submitted to the MAC-PHY sublayer error-free, after unpacking the data turned over to the MAC layer, and then determine whether it is the data distributed Benwang card, if then turned over, otherwise, discard. If the physical layer receives a signal distributed to Benwang card wrong, you will need to notify the sender to resend the packet information. NIC data need to be sent, we must first determine whether the channel is idle. If empty, a random backoff period of time to send, otherwise, they will not send. Card time division duplex, send not receive the receipt can not be made. Wireless LAN standard: 1.IEEE 802.11a : use the 5GHz band, the transmission speed of 54Mbps and 802.11b are not compatible; 2.IEEE 802.11b: 2.4GHz band, the transmission speed of 11Mbps; 3.IEEE 802.11g : use the 2.4GHz band, The transmission speed of 54Mbps and is backward compatible with 802.11b; 4.IEEE 802.11n (Draft 2.0): Intel's new Centrino 2 notebooks and high-end routing is backward compatible with the transmission speed of 300Mbps. Edit this paragraph card history of the development of card: (NICs) is the most important computer local area network connected devices, the main computer through the network card to connect to the network in the network, the network card work is twofold: on the one hand it is responsible for receiving the network upload over packets, unpack the data on the motherboard bus transfer to the local computer; the other hand, pack the data into it on the local computer network. Computer networks: the product of the development of computer and communication technologies, with the requirements of the community for information sharing, information dissemination and development. The so-called computer network is to use the geographic location of communications equipment and lines, and functional independence of more than one computer system interconnect featured network software (ie, network communication protocols , information exchange, and network operating systems , etc.) to achieve network resource sharing and information transfer systems. The computer network consists of: usually consists of three parts, the resource subnet , communication subnet and communication protocols. Resource subnet: is part of the user-oriented computer network, responsible for network-wide application-oriented data processing work, its subject is a client-oriented external devices connected to the computer network and the host computer, and these computers have the , software , and for sharing data. Communication subnet : responsible for the data communication part of a four-computer network, communication transmission medium such as twisted pair, coaxial cable, radio communications, microwave, optical fiber. Communication protocols : reliable and effective communication between computers within the network, the two parties that both sides must abide by the rules and conventions known as the communication protocol. • Resource sharing: including hardware and software resources. Hardware resources such as high-performance processing unit with special features, high-performance input and output devices (laser printers, plotters, etc.) as well as large-capacity auxiliary storage devices (such as tape drives , large capacity hard disk drive , etc.), and their sharing can save hardware overhead . Software resources such as software and data. · Local Area Network: a communications system, he allowed several independent of each other's computer, in the appropriate range, to communicate directly with the appropriate transmission rate. General network classified according to their size, we usually use in the office or at home, mostly belonging to the LAN, such a network due to the short distance between the computer and do not have too many network devices repeaters, so I feel like on speed faster, but for a smaller range. Wide area network (WAN) Wide Area Network: LAN relative where over LAN range, can be counted as the WAN. Metropolitan Area Networks (MAN) Metropolitan Area Network: network operating in a city within the network of urban infrastructure and telecommunications facilities (such as underground cable system) , or physically , and sometimes from the WAN to distinguish, called MAN . · Network architecture: refers to the overall design of the communication system, it provides a standard for network hardware, software, protocols, access control and topology . It is widely used is the International Organization for Standardization (ISO) in 1979, OSI (OSI-Open System Interconnection) reference model. OSI reference model, the physical layer, data link layer, network layer, transport layer, session layer, said layer and application layer seven-level description of the structure of the network, its specification is open to all manufacturers , with the guidance of an international network structure and open systems to the role . It directly affects the bus, interfaces, and network performance. Common network architecture, FDDI, Ethernet, Token Ring and Fast Ethernet. From the perspective of network interconnection , the key elements of the network architecture, protocol and topology. Protocol (Protocol): A formal description of the rules to be observed in the exchange of data between the data format and computer. Simply put, the computer on the network to be able to smooth communications with each other, we must speak the same language, the language is equivalent to an agreement, it is divided into Ethernet, NetBEUI, IPX / SPX, as well as the TCP / IP protocol . Topology: each site in the form of interconnected networks, the main bus topology , star topology, ring topology, and their hybrid. FDDI / CDDI: formulated by the American National Standards Institute ANSI X3T9.5. The rate of 100Mbps; CDDI are based on copper cables ( twisted pair ), FDDI,. FDDI technology is mature, the network can be extended to 100 km, and the use of the ring structure and excellent management capabilities , with high reliability. Expensive, complicated installation, standards, technology is mature, and support hardware and software products. IEEE802.5 / Token Ring Network: commonly used in the IBM system, the rate of its support for both 4Mbps and 16Mbps. Of Novell, IBM LAN Server supports 16MbpsIEEE802.5 / Token Ring network technology. Switched Ethernet: its support for the agreement is still with IEEE802.3 / Ethernet, but provides a separate 10Mbps ports. It is fully compatible with the original with IEEE802.3 / Ethernet, and overcome the decline in the efficiency of shared 10Mbps network. 100BASE-T Fast Ethernet: 10BASE- T difference is that a tenfold increase in the rate of the network, ie, 100M. Using the FDDI PMD protocol, but the price is cheaper than FDDI. 100BASE-T standard developed by IEEE802.3. 10BASE-T uses the same media access technology, similar to the step line rules and the same pin-out, easy to integrate with 10BASE-T. Each segment allows only two repeater , the maximum network span of 210 meters. . · IEEE802.3/Ethernet (Ethernet): currently the most widely used media access technology, usually in the OSI model physical layer and data link layer operation. Novell, Widows NT, IBM, UNIX Network LANServer, either the DECNET and other low-level media access technology, networking is a flexible, convenient, and supported by many hardware and software products. Its rate of sharing 10Mbps. Can be divided according to different media: 10BASE-2 (Coaxial Culan), 10BASE-5 (coaxial thin cable) 10BASE-T (twisted pair) and 10BASE-FL (fiber). The NETBIOS / NETBEUI: the NETBIOS LAN software interfaces, industry standard, can support a variety of transmission media . NETBEUI is the the NETBIOS expansion of user interface , used for Microaoft Windows NT and IBM LAN Manager. The NETBIOS developed earlier, relatively simple, does not consider the interconnection gateway, the naming scheme is not suitable for a variety of operating system. · IPX / SPX: NOVELL network protocol. At present, the hardware and software support for IPX / SPX, the I / O devices a lot. OSI reference model, which is equivalent to four layers (network layer, transport layer ). NOVELL network, you can load the IP protocol on IPX NETBIOS protocol. The TCP / IP: IP in UNIX are widely deployed to become the de facto international industry standard. IP is the Internet protocol. IP protocol across the LAN, WAN, and virtually all LAN and WAN equipment to support the IP protocol, the best agreement of the unified media transmission. IP protocol agreement for the data class, the better the response time of its transmission, less interaction of the protocol, more suited to the needs of high-speed transmission. · Bus topology: a single transmission line as a transmission medium, all sites directly through the hardware interface to connect to the trunk cable on the bus. · star topology : all sites are connected to a central point, this central point known as a network hub (HUB). All sites of the ring topology : serial connection to each other, as the same chain to form a loop called the ring. · Hybrid topology: ranking domain network interconnection between, there will be a mixed form of several topology, that is a hybrid topology. · transmission medium : the physical path between the sender and the recipient in the communication networks, twisted pair, coaxial cable and fiber optic cable commonly used network transmission medium . · UTP: the integrated wiring system, the most commonly used as a transmission medium, especially in the star network topology, twisted pair wiring material is essential. Twisted-pair cable package with a pair or a pair of twisted pair, made of two insulated copper wires wrapped around each other in order to reduce the degree of interference of the signal in order to reduce the degree of interference of the signal, each twisted pair generally. Twisted-pair unshielded twisted pair (UTP) and shielded twisted pair (STP), two categories can be divided into . Among them, the STP is divided into Category 3 and Category 5 UTP is divided into three categories, Category 4, Category 5, Category 5 super four kinds, 6 and 7 twisted pair will be in the near future used in computer network cabling system. RJ-45 connector : each twisted pair, two by installing the RJ-45 connector (commonly known as crystal head ) with the card and hub (or switch ) is connected. · Coaxial cable: a hollow cylindrical mesh copper conductor and a copper wire in the central axis, the copper wire between the hollow cylindrical conductor and the outside world with insulating material separated. Compared with twisted pair, coaxial cable, anti-jamming capability, shielding performance, so commonly used in the connection between the devices and equipment, or for the bus network topology. , Depending on the diameter, can be divided into two kinds of thin cable and Culan. · BNC connectors: the Thinnet both ends of the install the BNC connector, connected through dedicated T-connector and the card and the hub (or switch). · Fiber: Fiber that is, optical fiber is a small, flexible and the medium of transmission of optical signals , by the multi-fiber optical cable. With twisted pair and coaxial cable, fiber optic cable adapted to the requirements of the current network information on long-distance transmission capacity, plays a very important role in computer networks. Half-duplex : it means the card can receive to send data, but can only do an action, can not simultaneously send and receive. · Full-duplex: is to be able to receive and send signals, such as the telephone is a full-duplex transmission equipment, we listen to each other's speech at the same time, can also be the speaker to the other party. In theory, full-duplex transmission can improve network efficiency, but in fact still be useful in conjunction with other related equipment. Such as twisted pair network cable must be selected before the full-duplex transmission between connected hub (HUB), but also full-duplex transmission; Finally, using the network operating system also has to support full-duplex work industry, so that it can really play the power of the full-duplex transmission. · The Programmed I / O: This is from an earlier date, the effective transmission was NOVELL swept the world of the NE 2000 network card is in this way. Transmission efficiency of this transmission is not easy to improve the event of large amounts of data has become the bottleneck of transmission . Shared Memory: the kind of card data to be transferred into the memory card, and this memory must be occupied by the end of the address (address) the majority of occupied 640-1024KB between, with the address of this memory can be regarded as part of the motherboard memory: When the host data to the network card to go directly to the piece of memory to retrieve; Conversely, data into memory is tantamount to pass card. PROGRAMMED I / O that metaphor with a spoon to scoop the water, the SHARED the MEMORY is the bucket to fetch water, to better highlight its efficiency in traffic for a long time. Bus Master: this type of card, a control chip (CONTROLLER), designed to control the transmission process and the use of bus control action do the job by the chip, the data can be directly passed from the card to the motherboard, without the I / O PROT, without going through the CPU. Do not take up valuable CPU time, can effectively reduce the burden on the system, particularly on the server. The majority of the EISA, MCA, PCI interface card to support this the BUS MASTER to communicate with the motherboard. · 802.3x flow control: improved performance due to more efficient data transfer. NIC communicate with the switch to establish the optimal data transmission. Of Parallel the Tasking technology: COM's patented technology, this technology at 10Mbps or 100 Mbps connection make the highest data transfer speeds . Of Parallel the Tasking II technology: 3COM's patented technology, this technology can reduce CPU utilization and improve application performance , but also because of more efficient data transmission on the PCI bus . In the past, the main operating cycle of a bus card up to a time so that the 64- byte data transfer on the PCI bus. To a 1514-byte packet transmitted to the host PC, you need 24 separate bus master operation cycle, which makes the low efficiency of the bus. Have of Parallel the Tasking II technology, network cards on the bus in a bus master cycle transmission across the Ethernet data packet, which greatly improves the efficiency of the PCI bus. The result is to speed up the transfer speed and improved system performance, desktop and server applications work better. 32-bit bus master DMA: wide data path and the high-speed transmission, and low CPU utilization rate provides the best system performance. · Interactive access technology: network card can dynamically analyze network information flow, and then adjust the network performance. · Remote wake-up: network management command remote PC power in a central location, easy to update and maintain the desktop (PC motherboard must be equipped with a 3-foot remote wake up connector during off hours; with the requirements of the Desktop Management Application software, the software can generate a Magic Packet TM remote wake-up signal).
TYPES OF NETWORK INTERFACE CARDS(NIC)
Computer outside the LAN connection is inserted through the mainframe as a network interface board (or a PCMCIA card ) is inserted in the notebook computer . The network interface board is also known as communications adapter or network adapter (adapter) or Network Interface Card NIC (Network Interface Card), but now more people are willing to use the simple name "card".
Catalog card functionality briefly card functions Detailed card of the main functions of the following three
A package of data and re-opened
2 link management
(3) encoding and decoding
The genuineness of the identification card
(1) spray tin plate
(2) the quality of the main control chip
(3) The use of SMT SMD components
(4) titanium gold cheat
Considerations in the purchase card
Type of network
Transmission rate
Bus Type
NIC-supported cable interface
Price and brand
other knowledge of the network card wireless network card network card, network card Brand
Intel
Realtek
Broadcom
VIA and SIS
Card functions outlined the card functions Detailed card has the following three
A package of data and re-opened
2 link management
(3) encoding and decoding
The genuineness of the identification card
(1) spray tin plate
(2) the quality of the main control chip
(3) The use of SMT SMD components
(4) titanium gold cheat
Considerations in the purchase card
Type of network
Transmission rate
Bus Type
NIC-supported cable interface
Price and brand
other knowledge of the network card wireless network card network card
Common card brand
Intel
Realtek
Broadcom
VIA and SIS
Edit this paragraph card function briefly card work at the data link layer, network components, the LAN interface to connect computers and transmission media , not only able to match with the physical connection between the LAN transmission medium and electrical signals, but also involved in sending and receiving of the frame, the frame of the package and unpack, MAC , data encoding and decoding, and data caching functionality. Edit this paragraph card features Detailed network card fitted with a processor and memory (including RAM and ROM). Communication between the LAN and the LAN cable or twisted pair serial transmission. The communication between the card and the computer is a parallel transmission through the I / O bus on the computer motherboard . Therefore, an important feature of the network card is serial / parallel conversion. On the network data rate and data rate on the computer bus is not the same, must be equipped with a data cache memory chip in the card . Management network card device driver must install the network card installed in your computer's operating system . This driver will tell the card, should be sent over the LAN from the memory location will be data blocks stored. The network card is also Ethernet protocol. NIC is not independent self-governing unit, because the card itself, with no power but must be inserted in the computer's power supply, and subject to the control of the computer. Network card can be seen as a semi-autonomous unit. When the NIC receives a frame error, it will discard the frame without having to notify the computer that it is inserted. When the network card receives a correct frame, it interrupts to notify the computer and delivered to the network layer in the protocol stack . When the computer you want to send an IP packet, it will be down by the protocol stack to the NIC assembled framing sent to the LAN. With the continuous improvement of the integration, the number of chips on the card continually reduced, although a wide range of all manufacturers card, but its function is much the same. The main function to edit this paragraph, card data, together with the following three 1. data package and re-opened to send on the floor to pay down first and tail, the Ethernet frame. When receiving Ethernet frames stripped of the first and the tail, and then sent to a layer; 2 link management is the CSMA / CD (Carrier Sense Multiple Access with Collision Detection Carrier Sense Multiple Access with the Collision Detection, ) protocol implementation; 3 encoding and decoding, namely the Manchester encoding and decoding . Spray tin plate quality card board edit the genuineness of the identification card of this paragraph below, I will introduce a high-quality network card should have the conditions: (1) generally use the spray tin plate, the NIC sheet is white, while the poor card yellow. (2) the quality of the main control chip main control chip is the most important parts of the card , it often determines the performance of the merits of the network card , so the main control chip used in high-quality card is a mature product on the market. The market a lot of inferior card in order to reduce costs while using the older version of the main control chip, which undoubtedly played a discount to the network card performance. (3) The majority of the SMT chip component quality card In addition to the electrolytic capacitors and high voltage ceramic capacitors, and other resistance vessels most of the more reliable and stable than the plug-in SMT chip components. Inferior card is mostly plug-in, which makes heat dissipation and stability of the network card is not good enough. (4) titanium gold Goldfinger Goldfinger of high-quality card selection of titanium metal production, not only increases its anti-jamming capability and reduce interference with other devices, while Goldfinger's node of the arc-shaped design. Poor quality card they use a non-titanium gold, the node is a right angle turn, affect the performance of signal transmission . Edit this paragraph, the factors to consider in the purchase card to the correct selection of assembly, connections, and set the card is often the prerequisite and necessary condition for correct connectivity of the network. In general, the purchase card to consider the following factors: the type of network is now more popular Ethernet, Token Ring , FDDI network, choose should be based on the type of network to choose the corresponding card. Transfer rate should be based on the bandwidth requirements of the server or workstation, and combined with the physical transmission medium can provide the maximum transfer rate to select the transmission rate of the network card. To Ethernet, for example, the choice of rates have 10Mbps 10/100Mbps, 1000Mbps and even 10Gbps other, but not the rate the higher the more appropriate. For example, a computer connected with 100M transmission speed over twisted-pair configuration 1000M network card is a waste, because at best achieve only 100M of transmission rate. The bus type computer bus slot types: ISA, EISA, VESA, PCI and PCMCIA. Smart card for PCI or E ISA bus is usually on the server , and workstation available PCI or ISA bus ordinary card in a notebook computer with PCMCIA bus card or using a portable parallel interface card. The PC is basically no longer supports ISA connections, so when the purchase card for a PC, do not buy the outdated ISA card, but should be optional PCI card . The cable interface card supported by the NIC to the final with the network connection, so it must have an interface cable through its connection with other computer network equipment. Different network interface for the different network types , the common interface Ethernet RJ-45 interfaces, and thin coaxial cable, BNC connectors and thick coaxial, AUI interface, FDDI interfaces , ATM interfaces. And some network cards in order to apply to a wide range of application environments, provide two or more types of interface, if the card will also provide RJ-45, BNC interface or AUI interface. (A) RJ-45 interface : This is the most common type of card, but also the most widely used type of interface card, mainly due to the popularity of the twisted-pair Ethernet applications. This RJ-45 connector type of card is used in Ethernet twisted pair transmission medium, its interface is similar to a telephone interface RJ-11 RJ-45 is the 8-cell lines, and telephone The line interface is a 4-core, and usually only take two core lines (ISDN phone line connected to the 4-wire). Preliminary judgment by the two light colors work state of the network card on the card also comes with two status indicator light . (B) BNC Interface: This interface card used in Ethernet or Token Ring using thin coaxial cable as the transmission medium , the network card of this type of interface is rare, mainly because with a thin coaxial cable as a transmission The media network is relatively small. (C) AUI interface : this interface is the type of card pairs used in Ethernet or Token Ring to thick coaxial cable as the transmission medium of this type of interface card is rare. (D) The FDDI interface: This interface card is adapted to FDDI, ( Fiber Distributed Data Interface) network, this network with 100Mbps of bandwidth, but it uses the transmission medium is optical fiber, so this FDDI interface card interface optical interface. With the emergence of Fast Ethernet , it's speed superiority no longer exists, but it must be expensive optical fiber as the transmission medium's shortcomings and has not changed so very rare. (E) The ATM interface: This interface type of the card is used in ATM ( ATM ) fiber (or twisted pair) network. It provides the physical transmission speed up to 155Mbps price and brand at different rates, different brand of card prices vary greatly. Edit this paragraph, other knowledge of the card (1) NIC: Command Ping command to determine the network failure is a very useful tool to test the network connection status and information packet to send and receive status, is the most commonly used network testing commands. Ping to the target host ( address ) send an echo request packet after receipt of the request requires the target host to reply, in order to determine whether the network response time and native Unicom with the target host (address) . If the Ping is unsuccessful, you can predict the failure to appear in the following areas: cable failures, network adapter configuration is not correct, the IP address is not correct. Ping the success of the network still does not work then the problem probably lies in the software configuration of the network system , the Ping success can only guarantee a connected physical path between the machine and the target host . Command format : ping the IP address or host name [-t] [-a] [-n count] [-l size] the meaning of the parameters : -t keep to the target host to send data ; -a IP address format to display the target The network address of the host; -n count to specify the Ping how many times the specific number of times specified by the count; -size the size of the specified packet sent to the target host. For example, when your machine can not access the Internet, first of all, you want to confirm whether the failure of the local LAN. Assumes that the LAN proxy server IP address is 202.168.0.1, you can use Ping to avoid 202.168.0.1 command to see whether the machine Unicom and proxy servers. In another example, the commonly used commands to test the machine's network card is installed correctly is to ping 127.0.0.1 . Tracert command is used to display the packet arrives at the path that the target host, and display the time of each node is reached. Command functions with the Ping similar, but the information it obtained in much greater detail than the Ping command, which path packets are taking all the node's IP and the time it takes are displayed. This command is more suitable for large networks. The command format : the tracert IP address or host name [-d] [-h maximumhops-the j host_list] [-w timeout] parameter meanings : -d does not resolve the name of the target host ; -h maximum_hops, specify the search to the target address number of hops; - j host_list in accordance with the release of source routing list of hosts in the address ; -w timeout Specifies the timeout interval, the program default time unit is milliseconds . If we are behind the Tracert command with some parameters, but also can detect other more detailed information, such as using the parameter-d can specify procedures to track the host path information, but also to resolve the domain name of the target host. Netstat command that can help network administrators to understand the overall usage of the network. It can display the current active network connection details, such as network connections, routing tables and network interface information, statistics, total of which network connections are running. Command parameter, the command displays the status of the use of all agreements, these agreements include the TCP protocol, UDP protocol and IP protocol, and also can select a specific agreement and to view its specific information, but also displays all the host port number and the current host detailed routing information. Command format: netstat [-r] [-s] [-n] [-a] the meaning of the parameters: -r displays the contents of the routing table of the machine; -s display for each protocol in use (including the TCP protocol, UDP protocol, figures in tabular form, the IP protocol); -n Displays addresses and port; -a display all host port number. Winipcfg command in the form of the window shows the IP protocol configuration information, the command to display the physical address of the network adapter , the host's IP address, subnet mask and default gateway , host name, DNS server , node type can also view other relevant information. Which network adapter physical address is useful in the detection of network errors. Format of the command: winipcfg, [/?] [/ All] parameter meaning: / all Displays all the IP address configuration information; / batch file] command results written to the specified file; / renew_ all retry all network adapters; / release_all release all network adapters; / renew N-reset network adapter N; / release N Release Network Adapter N. (2) NIC: LED indicator In general, each card has a LED (Light Emitting Diode Light Emitting Diode) indicator, used to represent the different state of the network card to facilitate we view the network card is working properly. The typical LED indicators Link / Act, Full Power and Associates. Link / Act that a connection is active, Full whether full-duplex (Full Duplex), and Power is the power instructions. (3) NIC: the main chip card controller chip is the core component of the network card, the performance of a network card is good or bad, to see the quality of this chip. NIC's main control chip is generally using a 3.3V low-power design, 0.35μm chip technology, which allows it to quickly calculate the data flowing through the network card, so as to reduce the burden on the CPU. The following is commonly used in LAN controller chip. 1, the Realtek 8201BL: a common motherboard integrated network chip (also known as PHY network chip). PHY chip refers to the network control chip operation by the processor or the Southbridge chip processing, in order to simplify the circuit design, thereby reducing costs. 2, the Realtek 8139C / D: is the most used card one. 8139D major increase in power management features, while others are basically no different from 8139C chip. Chip supports 10M/100Mbps. 3, lntel Pro/100VE: lntel company's entry-level networking chips. 4, nForce MCP NVIDIA/3Com: nForce2 built-in function of two sets of network chips, the Realtek 8210BL PHY network chip and Broabcom AC101L PHY network chip. 5,3 Com 905C: C support 10/100Mbps speed. SiS900: originally a single network control chip, but is now integrated into the Southbridge chip. Support 100Mbps. (4) NIC: remote wake-up function remote wake technology (WOL, the Wake-on-LAN) is a network card in conjunction with other hardware and software, through the LAN remote boot of a technology, whether it be access to the computer how far away from us. in what position, as long as it is in the same LAN are able to start at any time. This technique is ideal for remote network management environment, if such a request should pay attention to the optional network card has this capability. Can be remotely wake up the computer hardware have certain requirements, mainly on the card, motherboard and power supply. (a) NIC : ability to achieve the remote wake-up, including one of the most important part is to support WOL network card. Remote wake up the computer's NIC must support WOL, used to wake up other computers on the network card you do not have to support WOL. In addition, when multiple network cards installed in a computer, only one of the one set as a remote wake. (b) Motherboard : must also support remote wake-up, through the "Power Management Setup" menu, see the CMOS has a "Wake on LAN" to confirm. In addition, the motherboard supports remote wake-up usually has a dedicated 3-wire outlet to give the card power supply (PCI 2.1 standard). Motherboards now usually support the PCI 2.2 standard, can be directly through the PCI slot NIC +3.3 V Standby power, if not connect the WOL power cord can achieve remote wake-up, therefore, may no longer provide the 3-pin socket. Motherboard whether support PCI2.2 standard, and available through the "Power Management Setup" menu of the View CMOS "Wake on PCI Card" to confirm. c power supply : Ruoyu remote wake-up computer installation must comply with the ATX 2.01 standard ATX power supply , +5 V Standby current is at least more than 600 mA . NIC is not installed successfully how to solve? The general reason may be that the NIC driver does not interrupt number or I / O value does not and the card itself, hardware failure caused by the network card is not installed successfully. You can for testing according to the following steps : (1) Such cards are generally factory set default value , these values include "interrupt" (IR Q value) is "3", the "I / O address range (ie, I / O) 300-31F ", you can double-click the name of the card here, to detect whether these values modified, if not, please correct the need to restart your computer (corrected). (2) If the value of the above has convinced is correct, the card still does not work properly (ie, in front of a yellow exclamation point), please re-enter the Device Manager tab, expand the "Ports (COM LPT) If there are "Communications Port (COM2)" word exists, you also need to shield the COM2 port. Default COM2 port will occupy the interrupt number 3, the initial value of the range of network card NE2000 compatible conflict, so that the card does not work. Operation, please restart the computer when the computer restarts, follow the prompts to press on the keyboard the "Del" key to enter the CMOS, then INTERGRATED PERIPHER A LS, select the "Onboard Serial Port 2", then on the keyboard the "Pae, Up" key to re-election as the "Disable" (disabled) CMOS, press the "Esc" key to return the main menu, press the F10 key to save the changes made after the restart the computer. (3) If that does not, then it is recommended that in the card name, right-click and choose "delete", and then restart the computer, and then re-strict steps to add this card. (4) The next try, you can replace what card slot to try. (5) If it still does not work, then either of this card is not NE2000 compatible series, either the network card itself is faulty. (6) Of course, if someone changes the sheets of card number of the interrupt and I / O values that you use the default value of natural is not enough, therefore, to be safe, you can find the complete installation of this card set disk run inside the setup program, check its default value, if different, and then again under the new value to be modified; If you run the setup program, the system prompts you to find the relevant card, your card is not plugged in or where the slot or the card itself has a hardware failure. Edit this paragraph Wireless LAN Wireless LAN definition of the so-called wireless network , is the use of wireless local area network (WLAN) radio waves as the information transmission medium, very similar to the use of wired network, the biggest difference is the transmission medium of the different, the use of radio technology instead of cable and wired network backup for each other, but unfortunately too slow. The wireless card terminal wireless network equipment, wireless terminal equipment for Internet use of the wireless coverage of the wireless LAN through a wireless connection network. Specifically, the wireless card is to make your computer can take advantage of wireless Internet device, but with the wireless card is also need for a connected wireless network if you are at home or the location of a wireless router or wireless AP (the AccessPoint wireless access point) coverage, you can connect to a wireless network through the wireless network card wireless Internet access. Microwave radio frequency technology is the wireless card works, notebook WIFI , GPRS , CDMA several wireless data transmission mode to the Internet, the latter two by China Mobile and China Unicom, the former Telecom or Netcom has been involved in, but do not more than the main WIFI base station has access to the Internet (in fact, is WIFI routers , etc.) and laptop with WIFI card. Say that the basic concept is similar to data via wireless transmission. Wireless Internet access, follow the 802.1q standard wireless access point signal, the wireless card to receive and send data via wireless transmission. According to the IEEE802.11 protocol, the wireless LAN card into the Media Access Control (MAC) layer and physical layer (PHY Layer) between the two, but also defines a media access control - physical (MAC-PHY) sublayer (Sublayers) . The MAC layer provides the interface between the host and the physical layer, and management of external memory , it corresponds to the NIC unit with wireless LAN hardware. The physical layer specific radio signal reception and emission, corresponds to the spread spectrum communication equipment with wireless LAN hardware. The physical layer provides packing and unpacking of the idle channel estimation CCA information to the MAC layer, in order to decide whether to send a signal through the control of the MAC layer wireless network CCSMA / CA protocol, the MAC-PHY sublayer of the data, the necessary control information on the front of the packet. IEEE802.11 protocol, physical layer must have at least one idle channel estimation method of the CCA signal. The wireless card works as follows: When the physical layer signal is received and confirmed to be submitted to the MAC-PHY sublayer error-free, after unpacking the data turned over to the MAC layer, and then determine whether it is the data distributed Benwang card, if then turned over, otherwise, discard. If the physical layer receives a signal distributed to Benwang card wrong, you will need to notify the sender to resend the packet information. NIC data need to be sent, we must first determine whether the channel is idle. If empty, a random backoff period of time to send, otherwise, they will not send. Card time division duplex, send not receive the receipt can not be made. Wireless LAN standard: 1.IEEE 802.11a : use the 5GHz band, the transmission speed of 54Mbps and 802.11b are not compatible; 2.IEEE 802.11b: 2.4GHz band, the transmission speed of 11Mbps; 3.IEEE 802.11g : use the 2.4GHz band, The transmission speed of 54Mbps and is backward compatible with 802.11b; 4.IEEE 802.11n (Draft 2.0): Intel's new Centrino 2 notebooks and high-end routing is backward compatible with the transmission speed of 300Mbps. Edit this paragraph card history of the development of card: (NICs) is the most important computer local area network connected devices, the main computer through the network card to connect to the network in the network, the network card work is twofold: on the one hand it is responsible for receiving the network upload over packets, unpack the data on the motherboard bus transfer to the local computer; the other hand, pack the data into it on the local computer network. Computer networks: the product of the development of computer and communication technologies, with the requirements of the community for information sharing, information dissemination and development. The so-called computer network is to use the geographic location of communications equipment and lines, and functional independence of more than one computer system interconnect featured network software (ie, network communication protocols , information exchange, and network operating systems , etc.) to achieve network resource sharing and information transfer systems. The computer network consists of: usually consists of three parts, the resource subnet , communication subnet and communication protocols. Resource subnet: is part of the user-oriented computer network, responsible for network-wide application-oriented data processing work, its subject is a client-oriented external devices connected to the computer network and the host computer, and these computers have the , software , and for sharing data. Communication subnet : responsible for the data communication part of a four-computer network, communication transmission medium such as twisted pair, coaxial cable, radio communications, microwave, optical fiber. Communication protocols : reliable and effective communication between computers within the network, the two parties that both sides must abide by the rules and conventions known as the communication protocol. • Resource sharing: including hardware and software resources. Hardware resources such as high-performance processing unit with special features, high-performance input and output devices (laser printers, plotters, etc.) as well as large-capacity auxiliary storage devices (such as tape drives , large capacity hard disk drive , etc.), and their sharing can save hardware overhead . Software resources such as software and data. · Local Area Network: a communications system, he allowed several independent of each other's computer, in the appropriate range, to communicate directly with the appropriate transmission rate. General network classified according to their size, we usually use in the office or at home, mostly belonging to the LAN, such a network due to the short distance between the computer and do not have too many network devices repeaters, so I feel like on speed faster, but for a smaller range. Wide area network (WAN) Wide Area Network: LAN relative where over LAN range, can be counted as the WAN. Metropolitan Area Networks (MAN) Metropolitan Area Network: network operating in a city within the network of urban infrastructure and telecommunications facilities (such as underground cable system) , or physically , and sometimes from the WAN to distinguish, called MAN . · Network architecture: refers to the overall design of the communication system, it provides a standard for network hardware, software, protocols, access control and topology . It is widely used is the International Organization for Standardization (ISO) in 1979, OSI (OSI-Open System Interconnection) reference model. OSI reference model, the physical layer, data link layer, network layer, transport layer, session layer, said layer and application layer seven-level description of the structure of the network, its specification is open to all manufacturers , with the guidance of an international network structure and open systems to the role . It directly affects the bus, interfaces, and network performance. Common network architecture, FDDI, Ethernet, Token Ring and Fast Ethernet. From the perspective of network interconnection , the key elements of the network architecture, protocol and topology. Protocol (Protocol): A formal description of the rules to be observed in the exchange of data between the data format and computer. Simply put, the computer on the network to be able to smooth communications with each other, we must speak the same language, the language is equivalent to an agreement, it is divided into Ethernet, NetBEUI, IPX / SPX, as well as the TCP / IP protocol . Topology: each site in the form of interconnected networks, the main bus topology , star topology, ring topology, and their hybrid. FDDI / CDDI: formulated by the American National Standards Institute ANSI X3T9.5. The rate of 100Mbps; CDDI are based on copper cables ( twisted pair ), FDDI,. FDDI technology is mature, the network can be extended to 100 km, and the use of the ring structure and excellent management capabilities , with high reliability. Expensive, complicated installation, standards, technology is mature, and support hardware and software products. IEEE802.5 / Token Ring Network: commonly used in the IBM system, the rate of its support for both 4Mbps and 16Mbps. Of Novell, IBM LAN Server supports 16MbpsIEEE802.5 / Token Ring network technology. Switched Ethernet: its support for the agreement is still with IEEE802.3 / Ethernet, but provides a separate 10Mbps ports. It is fully compatible with the original with IEEE802.3 / Ethernet, and overcome the decline in the efficiency of shared 10Mbps network. 100BASE-T Fast Ethernet: 10BASE- T difference is that a tenfold increase in the rate of the network, ie, 100M. Using the FDDI PMD protocol, but the price is cheaper than FDDI. 100BASE-T standard developed by IEEE802.3. 10BASE-T uses the same media access technology, similar to the step line rules and the same pin-out, easy to integrate with 10BASE-T. Each segment allows only two repeater , the maximum network span of 210 meters. . · IEEE802.3/Ethernet (Ethernet): currently the most widely used media access technology, usually in the OSI model physical layer and data link layer operation. Novell, Widows NT, IBM, UNIX Network LANServer, either the DECNET and other low-level media access technology, networking is a flexible, convenient, and supported by many hardware and software products. Its rate of sharing 10Mbps. Can be divided according to different media: 10BASE-2 (Coaxial Culan), 10BASE-5 (coaxial thin cable) 10BASE-T (twisted pair) and 10BASE-FL (fiber). The NETBIOS / NETBEUI: the NETBIOS LAN software interfaces, industry standard, can support a variety of transmission media . NETBEUI is the the NETBIOS expansion of user interface , used for Microaoft Windows NT and IBM LAN Manager. The NETBIOS developed earlier, relatively simple, does not consider the interconnection gateway, the naming scheme is not suitable for a variety of operating system. · IPX / SPX: NOVELL network protocol. At present, the hardware and software support for IPX / SPX, the I / O devices a lot. OSI reference model, which is equivalent to four layers (network layer, transport layer ). NOVELL network, you can load the IP protocol on IPX NETBIOS protocol. The TCP / IP: IP in UNIX are widely deployed to become the de facto international industry standard. IP is the Internet protocol. IP protocol across the LAN, WAN, and virtually all LAN and WAN equipment to support the IP protocol, the best agreement of the unified media transmission. IP protocol agreement for the data class, the better the response time of its transmission, less interaction of the protocol, more suited to the needs of high-speed transmission. · Bus topology: a single transmission line as a transmission medium, all sites directly through the hardware interface to connect to the trunk cable on the bus. · star topology : all sites are connected to a central point, this central point known as a network hub (HUB). All sites of the ring topology : serial connection to each other, as the same chain to form a loop called the ring. · Hybrid topology: ranking domain network interconnection between, there will be a mixed form of several topology, that is a hybrid topology. · transmission medium : the physical path between the sender and the recipient in the communication networks, twisted pair, coaxial cable and fiber optic cable commonly used network transmission medium . · UTP: the integrated wiring system, the most commonly used as a transmission medium, especially in the star network topology, twisted pair wiring material is essential. Twisted-pair cable package with a pair or a pair of twisted pair, made of two insulated copper wires wrapped around each other in order to reduce the degree of interference of the signal in order to reduce the degree of interference of the signal, each twisted pair generally. Twisted-pair unshielded twisted pair (UTP) and shielded twisted pair (STP), two categories can be divided into . Among them, the STP is divided into Category 3 and Category 5 UTP is divided into three categories, Category 4, Category 5, Category 5 super four kinds, 6 and 7 twisted pair will be in the near future used in computer network cabling system. RJ-45 connector : each twisted pair, two by installing the RJ-45 connector (commonly known as crystal head ) with the card and hub (or switch ) is connected. · Coaxial cable: a hollow cylindrical mesh copper conductor and a copper wire in the central axis, the copper wire between the hollow cylindrical conductor and the outside world with insulating material separated. Compared with twisted pair, coaxial cable, anti-jamming capability, shielding performance, so commonly used in the connection between the devices and equipment, or for the bus network topology. , Depending on the diameter, can be divided into two kinds of thin cable and Culan. · BNC connectors: the Thinnet both ends of the install the BNC connector, connected through dedicated T-connector and the card and the hub (or switch). · Fiber: Fiber that is, optical fiber is a small, flexible and the medium of transmission of optical signals , by the multi-fiber optical cable. With twisted pair and coaxial cable, fiber optic cable adapted to the requirements of the current network information on long-distance transmission capacity, plays a very important role in computer networks. Half-duplex : it means the card can receive to send data, but can only do an action, can not simultaneously send and receive. · Full-duplex: is to be able to receive and send signals, such as the telephone is a full-duplex transmission equipment, we listen to each other's speech at the same time, can also be the speaker to the other party. In theory, full-duplex transmission can improve network efficiency, but in fact still be useful in conjunction with other related equipment. Such as twisted pair network cable must be selected before the full-duplex transmission between connected hub (HUB), but also full-duplex transmission; Finally, using the network operating system also has to support full-duplex work industry, so that it can really play the power of the full-duplex transmission. · The Programmed I / O: This is from an earlier date, the effective transmission was NOVELL swept the world of the NE 2000 network card is in this way. Transmission efficiency of this transmission is not easy to improve the event of large amounts of data has become the bottleneck of transmission . Shared Memory: the kind of card data to be transferred into the memory card, and this memory must be occupied by the end of the address (address) the majority of occupied 640-1024KB between, with the address of this memory can be regarded as part of the motherboard memory: When the host data to the network card to go directly to the piece of memory to retrieve; Conversely, data into memory is tantamount to pass card. PROGRAMMED I / O that metaphor with a spoon to scoop the water, the SHARED the MEMORY is the bucket to fetch water, to better highlight its efficiency in traffic for a long time. Bus Master: this type of card, a control chip (CONTROLLER), designed to control the transmission process and the use of bus control action do the job by the chip, the data can be directly passed from the card to the motherboard, without the I / O PROT, without going through the CPU. Do not take up valuable CPU time, can effectively reduce the burden on the system, particularly on the server. The majority of the EISA, MCA, PCI interface card to support this the BUS MASTER to communicate with the motherboard. · 802.3x flow control: improved performance due to more efficient data transfer. NIC communicate with the switch to establish the optimal data transmission. Of Parallel the Tasking technology: COM's patented technology, this technology at 10Mbps or 100 Mbps connection make the highest data transfer speeds . Of Parallel the Tasking II technology: 3COM's patented technology, this technology can reduce CPU utilization and improve application performance , but also because of more efficient data transmission on the PCI bus . In the past, the main operating cycle of a bus card up to a time so that the 64- byte data transfer on the PCI bus. To a 1514-byte packet transmitted to the host PC, you need 24 separate bus master operation cycle, which makes the low efficiency of the bus. Have of Parallel the Tasking II technology, network cards on the bus in a bus master cycle transmission across the Ethernet data packet, which greatly improves the efficiency of the PCI bus. The result is to speed up the transfer speed and improved system performance, desktop and server applications work better. 32-bit bus master DMA: wide data path and the high-speed transmission, and low CPU utilization rate provides the best system performance. · Interactive access technology: network card can dynamically analyze network information flow, and then adjust the network performance. · Remote wake-up: network management command remote PC power in a central location, easy to update and maintain the desktop (PC motherboard must be equipped with a 3-foot remote wake up connector during off hours; with the requirements of the Desktop Management Application software, the software can generate a Magic Packet TM remote wake-up signal).
Catalog card functionality briefly card functions Detailed card of the main functions of the following three
A package of data and re-opened
2 link management
(3) encoding and decoding
The genuineness of the identification card
(1) spray tin plate
(2) the quality of the main control chip
(3) The use of SMT SMD components
(4) titanium gold cheat
Considerations in the purchase card
Type of network
Transmission rate
Bus Type
NIC-supported cable interface
Price and brand
other knowledge of the network card wireless network card network card, network card Brand
Intel
Realtek
Broadcom
VIA and SIS
Card functions outlined the card functions Detailed card has the following three
A package of data and re-opened
2 link management
(3) encoding and decoding
The genuineness of the identification card
(1) spray tin plate
(2) the quality of the main control chip
(3) The use of SMT SMD components
(4) titanium gold cheat
Considerations in the purchase card
Type of network
Transmission rate
Bus Type
NIC-supported cable interface
Price and brand
other knowledge of the network card wireless network card network card
Common card brand
Intel
Realtek
Broadcom
VIA and SIS
Edit this paragraph card function briefly card work at the data link layer, network components, the LAN interface to connect computers and transmission media , not only able to match with the physical connection between the LAN transmission medium and electrical signals, but also involved in sending and receiving of the frame, the frame of the package and unpack, MAC , data encoding and decoding, and data caching functionality. Edit this paragraph card features Detailed network card fitted with a processor and memory (including RAM and ROM). Communication between the LAN and the LAN cable or twisted pair serial transmission. The communication between the card and the computer is a parallel transmission through the I / O bus on the computer motherboard . Therefore, an important feature of the network card is serial / parallel conversion. On the network data rate and data rate on the computer bus is not the same, must be equipped with a data cache memory chip in the card . Management network card device driver must install the network card installed in your computer's operating system . This driver will tell the card, should be sent over the LAN from the memory location will be data blocks stored. The network card is also Ethernet protocol. NIC is not independent self-governing unit, because the card itself, with no power but must be inserted in the computer's power supply, and subject to the control of the computer. Network card can be seen as a semi-autonomous unit. When the NIC receives a frame error, it will discard the frame without having to notify the computer that it is inserted. When the network card receives a correct frame, it interrupts to notify the computer and delivered to the network layer in the protocol stack . When the computer you want to send an IP packet, it will be down by the protocol stack to the NIC assembled framing sent to the LAN. With the continuous improvement of the integration, the number of chips on the card continually reduced, although a wide range of all manufacturers card, but its function is much the same. The main function to edit this paragraph, card data, together with the following three 1. data package and re-opened to send on the floor to pay down first and tail, the Ethernet frame. When receiving Ethernet frames stripped of the first and the tail, and then sent to a layer; 2 link management is the CSMA / CD (Carrier Sense Multiple Access with Collision Detection Carrier Sense Multiple Access with the Collision Detection, ) protocol implementation; 3 encoding and decoding, namely the Manchester encoding and decoding . Spray tin plate quality card board edit the genuineness of the identification card of this paragraph below, I will introduce a high-quality network card should have the conditions: (1) generally use the spray tin plate, the NIC sheet is white, while the poor card yellow. (2) the quality of the main control chip main control chip is the most important parts of the card , it often determines the performance of the merits of the network card , so the main control chip used in high-quality card is a mature product on the market. The market a lot of inferior card in order to reduce costs while using the older version of the main control chip, which undoubtedly played a discount to the network card performance. (3) The majority of the SMT chip component quality card In addition to the electrolytic capacitors and high voltage ceramic capacitors, and other resistance vessels most of the more reliable and stable than the plug-in SMT chip components. Inferior card is mostly plug-in, which makes heat dissipation and stability of the network card is not good enough. (4) titanium gold Goldfinger Goldfinger of high-quality card selection of titanium metal production, not only increases its anti-jamming capability and reduce interference with other devices, while Goldfinger's node of the arc-shaped design. Poor quality card they use a non-titanium gold, the node is a right angle turn, affect the performance of signal transmission . Edit this paragraph, the factors to consider in the purchase card to the correct selection of assembly, connections, and set the card is often the prerequisite and necessary condition for correct connectivity of the network. In general, the purchase card to consider the following factors: the type of network is now more popular Ethernet, Token Ring , FDDI network, choose should be based on the type of network to choose the corresponding card. Transfer rate should be based on the bandwidth requirements of the server or workstation, and combined with the physical transmission medium can provide the maximum transfer rate to select the transmission rate of the network card. To Ethernet, for example, the choice of rates have 10Mbps 10/100Mbps, 1000Mbps and even 10Gbps other, but not the rate the higher the more appropriate. For example, a computer connected with 100M transmission speed over twisted-pair configuration 1000M network card is a waste, because at best achieve only 100M of transmission rate. The bus type computer bus slot types: ISA, EISA, VESA, PCI and PCMCIA. Smart card for PCI or E ISA bus is usually on the server , and workstation available PCI or ISA bus ordinary card in a notebook computer with PCMCIA bus card or using a portable parallel interface card. The PC is basically no longer supports ISA connections, so when the purchase card for a PC, do not buy the outdated ISA card, but should be optional PCI card . The cable interface card supported by the NIC to the final with the network connection, so it must have an interface cable through its connection with other computer network equipment. Different network interface for the different network types , the common interface Ethernet RJ-45 interfaces, and thin coaxial cable, BNC connectors and thick coaxial, AUI interface, FDDI interfaces , ATM interfaces. And some network cards in order to apply to a wide range of application environments, provide two or more types of interface, if the card will also provide RJ-45, BNC interface or AUI interface. (A) RJ-45 interface : This is the most common type of card, but also the most widely used type of interface card, mainly due to the popularity of the twisted-pair Ethernet applications. This RJ-45 connector type of card is used in Ethernet twisted pair transmission medium, its interface is similar to a telephone interface RJ-11 RJ-45 is the 8-cell lines, and telephone The line interface is a 4-core, and usually only take two core lines (ISDN phone line connected to the 4-wire). Preliminary judgment by the two light colors work state of the network card on the card also comes with two status indicator light . (B) BNC Interface: This interface card used in Ethernet or Token Ring using thin coaxial cable as the transmission medium , the network card of this type of interface is rare, mainly because with a thin coaxial cable as a transmission The media network is relatively small. (C) AUI interface : this interface is the type of card pairs used in Ethernet or Token Ring to thick coaxial cable as the transmission medium of this type of interface card is rare. (D) The FDDI interface: This interface card is adapted to FDDI, ( Fiber Distributed Data Interface) network, this network with 100Mbps of bandwidth, but it uses the transmission medium is optical fiber, so this FDDI interface card interface optical interface. With the emergence of Fast Ethernet , it's speed superiority no longer exists, but it must be expensive optical fiber as the transmission medium's shortcomings and has not changed so very rare. (E) The ATM interface: This interface type of the card is used in ATM ( ATM ) fiber (or twisted pair) network. It provides the physical transmission speed up to 155Mbps price and brand at different rates, different brand of card prices vary greatly. Edit this paragraph, other knowledge of the card (1) NIC: Command Ping command to determine the network failure is a very useful tool to test the network connection status and information packet to send and receive status, is the most commonly used network testing commands. Ping to the target host ( address ) send an echo request packet after receipt of the request requires the target host to reply, in order to determine whether the network response time and native Unicom with the target host (address) . If the Ping is unsuccessful, you can predict the failure to appear in the following areas: cable failures, network adapter configuration is not correct, the IP address is not correct. Ping the success of the network still does not work then the problem probably lies in the software configuration of the network system , the Ping success can only guarantee a connected physical path between the machine and the target host . Command format : ping the IP address or host name [-t] [-a] [-n count] [-l size] the meaning of the parameters : -t keep to the target host to send data ; -a IP address format to display the target The network address of the host; -n count to specify the Ping how many times the specific number of times specified by the count; -size the size of the specified packet sent to the target host. For example, when your machine can not access the Internet, first of all, you want to confirm whether the failure of the local LAN. Assumes that the LAN proxy server IP address is 202.168.0.1, you can use Ping to avoid 202.168.0.1 command to see whether the machine Unicom and proxy servers. In another example, the commonly used commands to test the machine's network card is installed correctly is to ping 127.0.0.1 . Tracert command is used to display the packet arrives at the path that the target host, and display the time of each node is reached. Command functions with the Ping similar, but the information it obtained in much greater detail than the Ping command, which path packets are taking all the node's IP and the time it takes are displayed. This command is more suitable for large networks. The command format : the tracert IP address or host name [-d] [-h maximumhops-the j host_list] [-w timeout] parameter meanings : -d does not resolve the name of the target host ; -h maximum_hops, specify the search to the target address number of hops; - j host_list in accordance with the release of source routing list of hosts in the address ; -w timeout Specifies the timeout interval, the program default time unit is milliseconds . If we are behind the Tracert command with some parameters, but also can detect other more detailed information, such as using the parameter-d can specify procedures to track the host path information, but also to resolve the domain name of the target host. Netstat command that can help network administrators to understand the overall usage of the network. It can display the current active network connection details, such as network connections, routing tables and network interface information, statistics, total of which network connections are running. Command parameter, the command displays the status of the use of all agreements, these agreements include the TCP protocol, UDP protocol and IP protocol, and also can select a specific agreement and to view its specific information, but also displays all the host port number and the current host detailed routing information. Command format: netstat [-r] [-s] [-n] [-a] the meaning of the parameters: -r displays the contents of the routing table of the machine; -s display for each protocol in use (including the TCP protocol, UDP protocol, figures in tabular form, the IP protocol); -n Displays addresses and port; -a display all host port number. Winipcfg command in the form of the window shows the IP protocol configuration information, the command to display the physical address of the network adapter , the host's IP address, subnet mask and default gateway , host name, DNS server , node type can also view other relevant information. Which network adapter physical address is useful in the detection of network errors. Format of the command: winipcfg, [/?] [/ All] parameter meaning: / all Displays all the IP address configuration information; / batch file] command results written to the specified file; / renew_ all retry all network adapters; / release_all release all network adapters; / renew N-reset network adapter N; / release N Release Network Adapter N. (2) NIC: LED indicator In general, each card has a LED (Light Emitting Diode Light Emitting Diode) indicator, used to represent the different state of the network card to facilitate we view the network card is working properly. The typical LED indicators Link / Act, Full Power and Associates. Link / Act that a connection is active, Full whether full-duplex (Full Duplex), and Power is the power instructions. (3) NIC: the main chip card controller chip is the core component of the network card, the performance of a network card is good or bad, to see the quality of this chip. NIC's main control chip is generally using a 3.3V low-power design, 0.35μm chip technology, which allows it to quickly calculate the data flowing through the network card, so as to reduce the burden on the CPU. The following is commonly used in LAN controller chip. 1, the Realtek 8201BL: a common motherboard integrated network chip (also known as PHY network chip). PHY chip refers to the network control chip operation by the processor or the Southbridge chip processing, in order to simplify the circuit design, thereby reducing costs. 2, the Realtek 8139C / D: is the most used card one. 8139D major increase in power management features, while others are basically no different from 8139C chip. Chip supports 10M/100Mbps. 3, lntel Pro/100VE: lntel company's entry-level networking chips. 4, nForce MCP NVIDIA/3Com: nForce2 built-in function of two sets of network chips, the Realtek 8210BL PHY network chip and Broabcom AC101L PHY network chip. 5,3 Com 905C: C support 10/100Mbps speed. SiS900: originally a single network control chip, but is now integrated into the Southbridge chip. Support 100Mbps. (4) NIC: remote wake-up function remote wake technology (WOL, the Wake-on-LAN) is a network card in conjunction with other hardware and software, through the LAN remote boot of a technology, whether it be access to the computer how far away from us. in what position, as long as it is in the same LAN are able to start at any time. This technique is ideal for remote network management environment, if such a request should pay attention to the optional network card has this capability. Can be remotely wake up the computer hardware have certain requirements, mainly on the card, motherboard and power supply. (a) NIC : ability to achieve the remote wake-up, including one of the most important part is to support WOL network card. Remote wake up the computer's NIC must support WOL, used to wake up other computers on the network card you do not have to support WOL. In addition, when multiple network cards installed in a computer, only one of the one set as a remote wake. (b) Motherboard : must also support remote wake-up, through the "Power Management Setup" menu, see the CMOS has a "Wake on LAN" to confirm. In addition, the motherboard supports remote wake-up usually has a dedicated 3-wire outlet to give the card power supply (PCI 2.1 standard). Motherboards now usually support the PCI 2.2 standard, can be directly through the PCI slot NIC +3.3 V Standby power, if not connect the WOL power cord can achieve remote wake-up, therefore, may no longer provide the 3-pin socket. Motherboard whether support PCI2.2 standard, and available through the "Power Management Setup" menu of the View CMOS "Wake on PCI Card" to confirm. c power supply : Ruoyu remote wake-up computer installation must comply with the ATX 2.01 standard ATX power supply , +5 V Standby current is at least more than 600 mA . NIC is not installed successfully how to solve? The general reason may be that the NIC driver does not interrupt number or I / O value does not and the card itself, hardware failure caused by the network card is not installed successfully. You can for testing according to the following steps : (1) Such cards are generally factory set default value , these values include "interrupt" (IR Q value) is "3", the "I / O address range (ie, I / O) 300-31F ", you can double-click the name of the card here, to detect whether these values modified, if not, please correct the need to restart your computer (corrected). (2) If the value of the above has convinced is correct, the card still does not work properly (ie, in front of a yellow exclamation point), please re-enter the Device Manager tab, expand the "Ports (COM LPT) If there are "Communications Port (COM2)" word exists, you also need to shield the COM2 port. Default COM2 port will occupy the interrupt number 3, the initial value of the range of network card NE2000 compatible conflict, so that the card does not work. Operation, please restart the computer when the computer restarts, follow the prompts to press on the keyboard the "Del" key to enter the CMOS, then INTERGRATED PERIPHER A LS, select the "Onboard Serial Port 2", then on the keyboard the "Pae, Up" key to re-election as the "Disable" (disabled) CMOS, press the "Esc" key to return the main menu, press the F10 key to save the changes made after the restart the computer. (3) If that does not, then it is recommended that in the card name, right-click and choose "delete", and then restart the computer, and then re-strict steps to add this card. (4) The next try, you can replace what card slot to try. (5) If it still does not work, then either of this card is not NE2000 compatible series, either the network card itself is faulty. (6) Of course, if someone changes the sheets of card number of the interrupt and I / O values that you use the default value of natural is not enough, therefore, to be safe, you can find the complete installation of this card set disk run inside the setup program, check its default value, if different, and then again under the new value to be modified; If you run the setup program, the system prompts you to find the relevant card, your card is not plugged in or where the slot or the card itself has a hardware failure. Edit this paragraph Wireless LAN Wireless LAN definition of the so-called wireless network , is the use of wireless local area network (WLAN) radio waves as the information transmission medium, very similar to the use of wired network, the biggest difference is the transmission medium of the different, the use of radio technology instead of cable and wired network backup for each other, but unfortunately too slow. The wireless card terminal wireless network equipment, wireless terminal equipment for Internet use of the wireless coverage of the wireless LAN through a wireless connection network. Specifically, the wireless card is to make your computer can take advantage of wireless Internet device, but with the wireless card is also need for a connected wireless network if you are at home or the location of a wireless router or wireless AP (the AccessPoint wireless access point) coverage, you can connect to a wireless network through the wireless network card wireless Internet access. Microwave radio frequency technology is the wireless card works, notebook WIFI , GPRS , CDMA several wireless data transmission mode to the Internet, the latter two by China Mobile and China Unicom, the former Telecom or Netcom has been involved in, but do not more than the main WIFI base station has access to the Internet (in fact, is WIFI routers , etc.) and laptop with WIFI card. Say that the basic concept is similar to data via wireless transmission. Wireless Internet access, follow the 802.1q standard wireless access point signal, the wireless card to receive and send data via wireless transmission. According to the IEEE802.11 protocol, the wireless LAN card into the Media Access Control (MAC) layer and physical layer (PHY Layer) between the two, but also defines a media access control - physical (MAC-PHY) sublayer (Sublayers) . The MAC layer provides the interface between the host and the physical layer, and management of external memory , it corresponds to the NIC unit with wireless LAN hardware. The physical layer specific radio signal reception and emission, corresponds to the spread spectrum communication equipment with wireless LAN hardware. The physical layer provides packing and unpacking of the idle channel estimation CCA information to the MAC layer, in order to decide whether to send a signal through the control of the MAC layer wireless network CCSMA / CA protocol, the MAC-PHY sublayer of the data, the necessary control information on the front of the packet. IEEE802.11 protocol, physical layer must have at least one idle channel estimation method of the CCA signal. The wireless card works as follows: When the physical layer signal is received and confirmed to be submitted to the MAC-PHY sublayer error-free, after unpacking the data turned over to the MAC layer, and then determine whether it is the data distributed Benwang card, if then turned over, otherwise, discard. If the physical layer receives a signal distributed to Benwang card wrong, you will need to notify the sender to resend the packet information. NIC data need to be sent, we must first determine whether the channel is idle. If empty, a random backoff period of time to send, otherwise, they will not send. Card time division duplex, send not receive the receipt can not be made. Wireless LAN standard: 1.IEEE 802.11a : use the 5GHz band, the transmission speed of 54Mbps and 802.11b are not compatible; 2.IEEE 802.11b: 2.4GHz band, the transmission speed of 11Mbps; 3.IEEE 802.11g : use the 2.4GHz band, The transmission speed of 54Mbps and is backward compatible with 802.11b; 4.IEEE 802.11n (Draft 2.0): Intel's new Centrino 2 notebooks and high-end routing is backward compatible with the transmission speed of 300Mbps. Edit this paragraph card history of the development of card: (NICs) is the most important computer local area network connected devices, the main computer through the network card to connect to the network in the network, the network card work is twofold: on the one hand it is responsible for receiving the network upload over packets, unpack the data on the motherboard bus transfer to the local computer; the other hand, pack the data into it on the local computer network. Computer networks: the product of the development of computer and communication technologies, with the requirements of the community for information sharing, information dissemination and development. The so-called computer network is to use the geographic location of communications equipment and lines, and functional independence of more than one computer system interconnect featured network software (ie, network communication protocols , information exchange, and network operating systems , etc.) to achieve network resource sharing and information transfer systems. The computer network consists of: usually consists of three parts, the resource subnet , communication subnet and communication protocols. Resource subnet: is part of the user-oriented computer network, responsible for network-wide application-oriented data processing work, its subject is a client-oriented external devices connected to the computer network and the host computer, and these computers have the , software , and for sharing data. Communication subnet : responsible for the data communication part of a four-computer network, communication transmission medium such as twisted pair, coaxial cable, radio communications, microwave, optical fiber. Communication protocols : reliable and effective communication between computers within the network, the two parties that both sides must abide by the rules and conventions known as the communication protocol. • Resource sharing: including hardware and software resources. Hardware resources such as high-performance processing unit with special features, high-performance input and output devices (laser printers, plotters, etc.) as well as large-capacity auxiliary storage devices (such as tape drives , large capacity hard disk drive , etc.), and their sharing can save hardware overhead . Software resources such as software and data. · Local Area Network: a communications system, he allowed several independent of each other's computer, in the appropriate range, to communicate directly with the appropriate transmission rate. General network classified according to their size, we usually use in the office or at home, mostly belonging to the LAN, such a network due to the short distance between the computer and do not have too many network devices repeaters, so I feel like on speed faster, but for a smaller range. Wide area network (WAN) Wide Area Network: LAN relative where over LAN range, can be counted as the WAN. Metropolitan Area Networks (MAN) Metropolitan Area Network: network operating in a city within the network of urban infrastructure and telecommunications facilities (such as underground cable system) , or physically , and sometimes from the WAN to distinguish, called MAN . · Network architecture: refers to the overall design of the communication system, it provides a standard for network hardware, software, protocols, access control and topology . It is widely used is the International Organization for Standardization (ISO) in 1979, OSI (OSI-Open System Interconnection) reference model. OSI reference model, the physical layer, data link layer, network layer, transport layer, session layer, said layer and application layer seven-level description of the structure of the network, its specification is open to all manufacturers , with the guidance of an international network structure and open systems to the role . It directly affects the bus, interfaces, and network performance. Common network architecture, FDDI, Ethernet, Token Ring and Fast Ethernet. From the perspective of network interconnection , the key elements of the network architecture, protocol and topology. Protocol (Protocol): A formal description of the rules to be observed in the exchange of data between the data format and computer. Simply put, the computer on the network to be able to smooth communications with each other, we must speak the same language, the language is equivalent to an agreement, it is divided into Ethernet, NetBEUI, IPX / SPX, as well as the TCP / IP protocol . Topology: each site in the form of interconnected networks, the main bus topology , star topology, ring topology, and their hybrid. FDDI / CDDI: formulated by the American National Standards Institute ANSI X3T9.5. The rate of 100Mbps; CDDI are based on copper cables ( twisted pair ), FDDI,. FDDI technology is mature, the network can be extended to 100 km, and the use of the ring structure and excellent management capabilities , with high reliability. Expensive, complicated installation, standards, technology is mature, and support hardware and software products. IEEE802.5 / Token Ring Network: commonly used in the IBM system, the rate of its support for both 4Mbps and 16Mbps. Of Novell, IBM LAN Server supports 16MbpsIEEE802.5 / Token Ring network technology. Switched Ethernet: its support for the agreement is still with IEEE802.3 / Ethernet, but provides a separate 10Mbps ports. It is fully compatible with the original with IEEE802.3 / Ethernet, and overcome the decline in the efficiency of shared 10Mbps network. 100BASE-T Fast Ethernet: 10BASE- T difference is that a tenfold increase in the rate of the network, ie, 100M. Using the FDDI PMD protocol, but the price is cheaper than FDDI. 100BASE-T standard developed by IEEE802.3. 10BASE-T uses the same media access technology, similar to the step line rules and the same pin-out, easy to integrate with 10BASE-T. Each segment allows only two repeater , the maximum network span of 210 meters. . · IEEE802.3/Ethernet (Ethernet): currently the most widely used media access technology, usually in the OSI model physical layer and data link layer operation. Novell, Widows NT, IBM, UNIX Network LANServer, either the DECNET and other low-level media access technology, networking is a flexible, convenient, and supported by many hardware and software products. Its rate of sharing 10Mbps. Can be divided according to different media: 10BASE-2 (Coaxial Culan), 10BASE-5 (coaxial thin cable) 10BASE-T (twisted pair) and 10BASE-FL (fiber). The NETBIOS / NETBEUI: the NETBIOS LAN software interfaces, industry standard, can support a variety of transmission media . NETBEUI is the the NETBIOS expansion of user interface , used for Microaoft Windows NT and IBM LAN Manager. The NETBIOS developed earlier, relatively simple, does not consider the interconnection gateway, the naming scheme is not suitable for a variety of operating system. · IPX / SPX: NOVELL network protocol. At present, the hardware and software support for IPX / SPX, the I / O devices a lot. OSI reference model, which is equivalent to four layers (network layer, transport layer ). NOVELL network, you can load the IP protocol on IPX NETBIOS protocol. The TCP / IP: IP in UNIX are widely deployed to become the de facto international industry standard. IP is the Internet protocol. IP protocol across the LAN, WAN, and virtually all LAN and WAN equipment to support the IP protocol, the best agreement of the unified media transmission. IP protocol agreement for the data class, the better the response time of its transmission, less interaction of the protocol, more suited to the needs of high-speed transmission. · Bus topology: a single transmission line as a transmission medium, all sites directly through the hardware interface to connect to the trunk cable on the bus. · star topology : all sites are connected to a central point, this central point known as a network hub (HUB). All sites of the ring topology : serial connection to each other, as the same chain to form a loop called the ring. · Hybrid topology: ranking domain network interconnection between, there will be a mixed form of several topology, that is a hybrid topology. · transmission medium : the physical path between the sender and the recipient in the communication networks, twisted pair, coaxial cable and fiber optic cable commonly used network transmission medium . · UTP: the integrated wiring system, the most commonly used as a transmission medium, especially in the star network topology, twisted pair wiring material is essential. Twisted-pair cable package with a pair or a pair of twisted pair, made of two insulated copper wires wrapped around each other in order to reduce the degree of interference of the signal in order to reduce the degree of interference of the signal, each twisted pair generally. Twisted-pair unshielded twisted pair (UTP) and shielded twisted pair (STP), two categories can be divided into . Among them, the STP is divided into Category 3 and Category 5 UTP is divided into three categories, Category 4, Category 5, Category 5 super four kinds, 6 and 7 twisted pair will be in the near future used in computer network cabling system. RJ-45 connector : each twisted pair, two by installing the RJ-45 connector (commonly known as crystal head ) with the card and hub (or switch ) is connected. · Coaxial cable: a hollow cylindrical mesh copper conductor and a copper wire in the central axis, the copper wire between the hollow cylindrical conductor and the outside world with insulating material separated. Compared with twisted pair, coaxial cable, anti-jamming capability, shielding performance, so commonly used in the connection between the devices and equipment, or for the bus network topology. , Depending on the diameter, can be divided into two kinds of thin cable and Culan. · BNC connectors: the Thinnet both ends of the install the BNC connector, connected through dedicated T-connector and the card and the hub (or switch). · Fiber: Fiber that is, optical fiber is a small, flexible and the medium of transmission of optical signals , by the multi-fiber optical cable. With twisted pair and coaxial cable, fiber optic cable adapted to the requirements of the current network information on long-distance transmission capacity, plays a very important role in computer networks. Half-duplex : it means the card can receive to send data, but can only do an action, can not simultaneously send and receive. · Full-duplex: is to be able to receive and send signals, such as the telephone is a full-duplex transmission equipment, we listen to each other's speech at the same time, can also be the speaker to the other party. In theory, full-duplex transmission can improve network efficiency, but in fact still be useful in conjunction with other related equipment. Such as twisted pair network cable must be selected before the full-duplex transmission between connected hub (HUB), but also full-duplex transmission; Finally, using the network operating system also has to support full-duplex work industry, so that it can really play the power of the full-duplex transmission. · The Programmed I / O: This is from an earlier date, the effective transmission was NOVELL swept the world of the NE 2000 network card is in this way. Transmission efficiency of this transmission is not easy to improve the event of large amounts of data has become the bottleneck of transmission . Shared Memory: the kind of card data to be transferred into the memory card, and this memory must be occupied by the end of the address (address) the majority of occupied 640-1024KB between, with the address of this memory can be regarded as part of the motherboard memory: When the host data to the network card to go directly to the piece of memory to retrieve; Conversely, data into memory is tantamount to pass card. PROGRAMMED I / O that metaphor with a spoon to scoop the water, the SHARED the MEMORY is the bucket to fetch water, to better highlight its efficiency in traffic for a long time. Bus Master: this type of card, a control chip (CONTROLLER), designed to control the transmission process and the use of bus control action do the job by the chip, the data can be directly passed from the card to the motherboard, without the I / O PROT, without going through the CPU. Do not take up valuable CPU time, can effectively reduce the burden on the system, particularly on the server. The majority of the EISA, MCA, PCI interface card to support this the BUS MASTER to communicate with the motherboard. · 802.3x flow control: improved performance due to more efficient data transfer. NIC communicate with the switch to establish the optimal data transmission. Of Parallel the Tasking technology: COM's patented technology, this technology at 10Mbps or 100 Mbps connection make the highest data transfer speeds . Of Parallel the Tasking II technology: 3COM's patented technology, this technology can reduce CPU utilization and improve application performance , but also because of more efficient data transmission on the PCI bus . In the past, the main operating cycle of a bus card up to a time so that the 64- byte data transfer on the PCI bus. To a 1514-byte packet transmitted to the host PC, you need 24 separate bus master operation cycle, which makes the low efficiency of the bus. Have of Parallel the Tasking II technology, network cards on the bus in a bus master cycle transmission across the Ethernet data packet, which greatly improves the efficiency of the PCI bus. The result is to speed up the transfer speed and improved system performance, desktop and server applications work better. 32-bit bus master DMA: wide data path and the high-speed transmission, and low CPU utilization rate provides the best system performance. · Interactive access technology: network card can dynamically analyze network information flow, and then adjust the network performance. · Remote wake-up: network management command remote PC power in a central location, easy to update and maintain the desktop (PC motherboard must be equipped with a 3-foot remote wake up connector during off hours; with the requirements of the Desktop Management Application software, the software can generate a Magic Packet TM remote wake-up signal).
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