Sunday, July 20, 2008

Ethernet




Network switch


Typical SOHO network switch.

Back view of Atlantis network switch with Ethernet ports.
A network switch is a computer networking device that connects network segments. In the past, it was faster to use Layer 2 techniques to switch, when only MAC addresses could be looked up in content addressable memory (CAM). With the advent of ternary CAM (TCAM), it was equally fast to look up an IP address or a MAC address. TCAM is expensive, but very appropriate for enterprise switches that use default routes plus a moderate number of other routes. For routers that need a full Internet routing table, TCAM may not be cost-effective.
The first Ethernet switch was introduced by Kalpana in 1989. [1]
Contents[hide]
1 Function
2 Role of switches in networks
3 Layer-specific functionality
3.1 Layer-1 hubs versus higher-layer switches
3.2 Layer 2
3.3 Layer 3
3.4 Layer 4
3.5 Layer 7
4 Types of switches
4.1 Form factor
4.2 Configuration options
4.2.1 Traffic monitoring on a switched network
4.2.2 Typical switch management features
5 See also
6 References
7 External links




Ethernet
From Wikipedia, the free encyclopedia
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A standard Ethernet cord.
Ethernet is a family of frame-based computer networking technologies for local area networks (LANs). The name comes from the physical concept of the ether. It defines a number of wiring and signaling standards for the physical layer, through means of network access at the Media Access Control (MAC)/Data Link Layer, and a common addressing format.
Ethernet is standardized as IEEE 802.3. The combination of the twisted pair versions of Ethernet for connecting end systems to the network, along with the fiber optic versions for site backbones, is the most widespread wired LAN technology. It has been in use from around 1980[1] to the present, largely replacing competing LAN standards such as token ring, FDDI, and ARCNET.
Contents[hide]
1 History
2 General description
3 Dealing with multiple clients
3.1 CSMA/CD shared medium Ethernet
3.1.1 Main procedure
3.1.2 Collision detected procedure
3.2 Ethernet repeaters and hubs
3.3 Bridging and switching
3.4 Dual speed hubs
3.5 More advanced networks
4 Autonegotiation and duplex mismatch
5 Physical layer
6 Ethernet frame types and the EtherType field
6.1 Runt frames
7 Varieties of Ethernet
7.1 Some early varieties
7.2 10Mbit/s Ethernet
7.3 Fast Ethernet
7.4 Gigabit Ethernet
7.5 10 gigabit Ethernet
8 Related standards
9 See also
10 References
11 External links

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