Spanning Tree Question

[kunz12]

Guys -

I am trying to get a better handle on network redudancy that can be implemented using STP. From what I have read thus far, STP provides redundancy for broken links. For e.g. if we have 3 switches (A, B & C), if A is connected to both B&C, and B&C are connected to each other, there are multiple paths from A to B. So if a link between A & B fails, packets can get to B from A using switch C.

So my question is, how does STP provide redundancy for switch failures or does it not? If switch B fails completely, how should I implement redundancy. Assume all 3 switches have users connected to them and none of them are being used as backup for another.

Thanks for your help.

 

[brianinms]

STP is meant to prevent network loops not to provide redundancy. However, you can create a loop and allow STP to prune said look for some redundancy.

Personally if I was worried that much about redundancy, I would purchase a stack of 3750's.

 

[zinkann]

are all 3 switches located in the same location like a closet or hut?

CCNA, Network+

 

[burtsbees]

Hut...lol

Burt

 

[kunz12]

All 3 switches would be located in the same network rack and connected using a stacking cable.

Brianinms - Could you elaborate what you mean by suggesting to buy a stack of 3750's? How will that provide redundancy. Also if we do buy a stack of 3750's, would we have to configure STP on it?

Thanks again!

 

[lerdalt]

the 3750's have a stacking capability built into them. On the back they have a stackwise connector that you can stack the switches together. Then you manage 3 switches as 1. If one fails, as long as you have the 3 connected like you described above (a to b, b to c, c to a), if one fails, you only lose that block of ports.

The key is are you connecting them back to anything? You'll want to have 2 switches in the stack connected back to your core.

Personally, I really like the 3750's. Been really impressed with them so far. But I know there are some code problems with some of the latest releases.

 

[vipergg]

Getting them to upgrade if the switch codes are different is a real adventure .

 

[lerdalt]

oh yeah..learned the hard way that if you push a newer code to the switches and don't get them all rebooted at the same time, it's a big issue.

But I've been hearing there are some bugs in some of the newest releases around dhcp snooping and other features.