1 Network Interface Cards (NICs) ITEC 370 George Vaughan Franklin University

2 Sources for Slides Material in these slides comes primarily from course text, Guide to Networking Essentials,Tomsho, Tittel, Johnson (2007). Other sources are cited in line and listed in reference section.

3 TCP/IP and OSI Models

4 NIC NIC – Network Interface Card Hardware that connects computer to Network Media NIC plugs into computer backplane (bus). NIC is gate keeper for computer. Uploading data: –NIC reads data (bits) from the system bus (parallel) –NIC packages data into frames along with error check codes and address. –NIC ships frames out onto the network medium (serial) Downloading data: –NIC reads frames from network medium and checks address (serial) –NIC unpacks data and performs error checking –NIC places data (in bits) onto the system bus (parallel)

5 From Parallel to Serial and Vice Versa Tomsho, Tittel, Johnson (2007). Bus width

6 NIC and Backplane (Bus) NIC plugs into computer backplane (bus). The backplane (bus) on a computer: –Is a connection between CPU, memory, and certain devices such as the NIC. –Typically supports 32 bit or 64 bit parallel communication (for high speed) –Bus types described later. NIC must match the number of bits in backplane (bus width). Many computers have incorporated the functionality of NIC on motherboard.

7 Bus Types

8 NIC and Network Media NIC also has an interface to the network. Interface may be a wired or wireless serial connection. Wire interface may support coax, twisted- pair or fiber or some combination of the three. Wireless interface consists of a transceiver and antenna (which may be internal to card).

9 NIC With Multiple Interfaces Tomsho, Tittel, Johnson (2007)

10 Wireless Adapters Tomsho, Tittel, Johnson (2007)

11 NIC Buffer NIC also contains a buffer (memory) Buffer is used to manage traffic bursts either from the CPU or from network. Buffers allow CPU and network to operate more efficiently. The bigger the buffer, the better the performance of both CPU and network. A slow NIC can affect others on network.

12 NIC Address and OSI Model NIC has link address burned in (MAC address) MAC = Media Access Control – 48 bits. MAC Example (Hex): 00:20:ED:73:B7:1D –First 3 numbers = Manufacturer (Red) –Last 3 numbers = Unique Address for the card (Turquoise) MAC Address is burned on card NIC manages layer 2 (link layer) for computer. NIC also provides interface to network media (layer 1 or physical layer).

13 Available NIC Features Direct Memory Access (DMA) – direct access to CPU memory. Shared Adapter Memory – NIC buffer mapped into CPU memory Shared System Memory – CPU memory mapped into NIC buffer Bus Mastering – NIC can control Bus NIC Buffer Size On-board Co-processors – NIC can process network data w/o main CPU

14 Available NIC Features Security – NIC on-board support for IPSec Traffic Management – Quality of Service (QoS) Automatic Link Aggregation – Multiple NICs to multiply bandwidth Fault tolerance – Multiple NICs Wake-on-Lan – Remote computer power- up by special signal received by NIC.

15 Choosing Network Adapters for Best Performance Tomsho, Tittel, Johnson (2007) Increased performance features have payoffs for servers that might not apply to workstations –The following is a checklist for purchasing NICs: Bus width—Higher is better Bus type—Use 64-bit PCI-X or PCIe for servers Memory transfer—Shared memory outpaces I/O or DMA Special features—Choose security, management, protocol-handling, and hot-plug capabilities Bus mastering—Important for servers Vendor factors—Look for quality, reliability, staying power, and reputation

16 References Tomsho, Tittel, Johnson (2007). Guide to Networking Essentials. Boston: Thompson Course Technology. Odom, Knott (2006). Networking Basics: CCNA 1 Companion Guide. Indianapolis: Cisco Press Wikipedia (n.d.). OSI Model. Retrieved 09/12/2006 from