L2 switches and hubs

[sarahr202]

Hi every body!

I have a question.

According to my book, switches support rate adaptation,which means that device that use different ethernet speeds can communicate through the switch while hubs do not support rate adaptation.

=======================================

Do we have hubs for different speed? for example in order to connect two pc which support 10 Mbps speed, i must find the hub with 10 mbps ports?

we can not connect pc( 10 mbps) to hub which support only 100 mbps speed. Can we?

thanks a lot!

[Laurent Aubert · Accepted solution]

Hi,

Dual speed hubs are available.

HTH

Laurent.

[sarahr202]

Thanks Laurent and have a nice weekend!

[Joseph W. Doherty]

BTW, my understanding of dual speed 10/100 hubs, they actually provide an internal 2 port bridge between the 10 and 100 segments.

For routine traffic, normally you wouldn't care. However, if you wanted to use such a hub to perform traffic analysis, it's possible the bridge might not forward unicast traffic if it knows receiving MAC isn't on other bandwidth segment.

If there's a bridge, it might also be possible to extend hubs beyond normal Ethernet repeater restrictions (i.e. the 5-4-3 rules for 10 Mbps, and 2 Class II hubs for 100 Mbps) if you forced traffic across different bandwidth segments.