Switching different speed rates

[Foxy2]

How does a switch deal with different transmission speeds - eg if a port is running at 100meg full duplex is talking to a port that is running at 10meg half duplex?

 

[jimbopalmer]

For short bursts, there are buffers on each port on the switch, so they can get a little behind and not lose packets.

If it is a managed switch, there may be a 'deferred packets' counter so you can see if it gets bad.

More long term congestion is combated by IEEE 802.3x, which has provisions for 'back pressure' feedback if a link is overwhelmed.

I have no idea how to detect that it is being invoked, though.

I tried to remain child-like, all I acheived was childish.

 

[pansophic]

When the devices are plugged in, all of the 10/100 devices will announce to the other device what modes that they can operate in. With the 10/half devices it is easy, they don't even know of the other rates, so the switch can adapt its configuration.

There are times when you have two autosensing devices that just can't arrive at a concensus. If you set one of them to a single configuration, the other will arrive at that same answer.

Here is a short tutorial on auto-sensing and auto-negotiation:

http://www.cites.uiuc.edu/network/autosense.html

pansophic