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switches, collision domains

Can anyone tell me how switches break up collision domains, what exactly is is breaking it up ?

3 REPLIES
New Member

Re: switches, collision domains

In short: buffering.

Bronze

Re: switches, collision domains

Well, every port of a switch belongs to a seperate collision domain. A switch is an intelligent device which can keep track of CSMA/CD principles.

--Pls rate if useful--

Green

Re: switches, collision domains

Switches are just a flavor of a bridge.

Bridges sit between segments and only pass traffic if it recognizes that the destination (MAC) address is on another segment. If it sees a MAC that it doens't know, it floods the frame out all ports except the one that sourced the frame.

Each segment operates as an independent broadcast domain, so what a switch / bridge does is break up what would be one large collision domain (like back in the "hub days") into smaller more manageble collision domains.

Switch / bridge operation is also necessary to support full duplex operation (since all hosts can have a "private" collision domain i.e., one host per port).

Check out the following link. It will cover switch / bridge operation in more detail.

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/index.htm

This is the online version of Cisco's Inter-Networking Guide, which is also a very large (and expensive) book. If you need to find it in the future, just Google for "Internetworking" and it's always / usually at the top of the list.

Good Luck

Scott

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