Download NICs

Network Interface Cards
(NICs)
ITEC 370
George Vaughan
Franklin University
1
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.
2
TCP/IP and OSI Models
TCP/IP and OSI Models (OSI-Model, n.d.) and (Tomsho, 2007)
TCP/IP
Layers
Application
PDU
Data
OSI Layers
7 Application
6
5
Transport
Segments 4
Network
Packets
3
Link
Frames
2
Function
Network process to application,
Initiates or accepts a request to transfer
data
Presentation Adds formatting, display, and
encryption of information
Session
Adds communication session control
information, Login/Logout
Transport
Adds End-to-end connections and
reliability, re-sequencing, flow control
Network
Path determination and logical
addressing (IP), translates MAC
address to logical address
LLC
Data
Adds error checking and physical
Link
addressing (MAC & LLC)
Devices - Apps
Standards
Browsers,
servers,
Gateways
Gateways
HTTP, SNMP,
FTP, Telnet
DNS,
Gateways
Gateways
NetBIOS
Routers
IP, ICMP,
ARP, NetBEUI
Switches,
Bridges, NICs
802.3, 802.11,
FDDI
ASCII, MPEG
TCP, UDP
MAC
Bits
1 Physical
Media, signal and binary transmission, Hubs,
sends data as a bit stream
Repeaters
10Base-T, T1,
E1
3
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)
4
From Parallel to Serial and Vice Versa
Tomsho, Tittel, Johnson (2007).
Bus width
5
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.
6
Bus Types
Common Bus Types (Yomsho, 2007)
Bus Type
Introduced
(Wikipedia)
ISA
1981
Extended ISA
(EISA)
Micro Channel
Architecture (MCA)
PCI
1988
PCI-X
Bus
Speed
Bus Size
(Width)
33 MBps
16 or 32
bits
16 or 32
bits
32 and 64
bits
32 and 64
bits
1 to 32
Serial
Lines
32 bits
1987
4.77
MHz
8.33
MHz
10 MHz
1990
33 MHz
533 MBps
1998
66-533
MHz
4 GBps
PCI Express (PCIe) 2004
PCMCIA
Max
Transfer
Rate
16 MBps
264 MBps
8 GBps
33 MHz
132 MBps
Notes
8 or 16 bits Early PCs
Obsolete
Obsolete
Standard
Servers, high-end
workstations
Servers, high-end
workstations
Laptop
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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, twistedpair or fiber or some combination of the
three.
• Wireless interface consists of a transceiver
and antenna (which may be internal to
card).
8
NIC With Multiple Interfaces
Tomsho, Tittel, Johnson (2007)
9
Wireless Adapters
Tomsho, Tittel, Johnson (2007)
10
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):
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).
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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 powerup 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 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
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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
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