Network Interface Cards NICs

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Network Interface Cards (NICs)

• ITEC 370
• George Vaughan
• Franklin University

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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.

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TCP/IP and OSI Models
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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)

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

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Bus Types
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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).

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NIC With Multiple Interfaces Tomsho, Tittel,
Johnson (2007)
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Wireless Adapters Tomsho, Tittel, Johnson (2007)
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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.

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NIC Address and OSI Model

• NIC has link address burned in (MAC address)
• MAC Media Access Control 48 bits.
• MAC Example (Hex)
• 0020ED73B71D
• 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).

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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

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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.

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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 widthHigher is better
• Bus typeUse 64-bit PCI-X or PCIe for servers
• Memory transferShared memory outpaces I/O or DMA
• Special featuresChoose security, management,
  protocol-handling, and hot-plug capabilities
• Bus masteringImportant for servers
• Vendor factorsLook for quality, reliability,
  staying power, and reputation

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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 http//en.wikipedia.org/wiki/OSI_Model