Cisco Catalyst 3550

You're certainly on the right track !

'redundant ethernet links' = explain ?


Wow it feels nice to *ask* a question for a change !!
lol

In Ethernet you can't have any network loops, formed by more than one Ethernet connection between two points. If you do, you get the packet equivalent of feedback (well known to heavy metal guitarists sahir) and broadcast storms etc. So when you have redundant Ethernet links you use Spanning Tree Protocol or one of its more modern variants to block all but one possible path. If you lose that path, spanning tree can re-enable one of the other ones and maintain connectivity. That's the theory anyway, but in practice it's clunky and the users have more than enough time to see the transition!

Sahir,

Redundant Ethernet links means that there are at least 2 links to each switch for full redundancy. Should one link fail, the other one takes over and the network continues to operate.

To be acurate, the links are actually fiber gigabit links as they connect to the network backbone switches.

To help you get an idea, the diagram would look something like this:

switch======root switch=====switch

Here we've got two normal switches connected with redundant links ( to a root switch.

What's important to note is that not both links to each switch are active. Because the above setup would cause loops in the network, one of the two links is blocked, while the other remains active. This is done pretty much automatically by the STP protocol which will be covered after the VLAN topic as you already know.

Cheers!

Speaking of STP my LINKSYS Wireless Broadband Router (WRT54G) runs the STP. I was surprised to find STP running.

*slaps head in disgust*... ahh a switching loop.. I knew that
Didn't know it was called a redundant link though.