cisco switch 2960 spanning tree

amanzoor
amanzoor used Ask the Experts™
on
Hi,
I can see these lines on my show run from cisco 2960 switch:
spanning-tree mode pvst
spanning-tree etherchannel guard misconfig
spanning-tree extend system-id
Does spanning tree run as default on these switches or I have to disable it? how?
Thanks
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Why would you like spanning tree disabled, it is very important when there is more than a single switch in the environment.  The command you see is Spanning-tree mode pvst turns it on to per vlan spanning tree.

Is there a need to turn this off?
President
Commented:
Hi,

Spanning-tree porocol is a Layer 2 protocol which is responsible for preventing loops over bridges such as anorther switch connected to two ports of the switch. In such a situation the MAc buffer will be full and ther will be lloops / Delays / Denial of Service. However since STP is there it can prevent such things to happen. Ok now I ask you why should you disable such a protocol and render your device vulnerable to such a problem in your network ??

Cheers,
K.
Commented:
We disable spanning tree on trunk ports because we run bdu guard, and if it is not turned off the switch disables the port on the link to the next switch.  We do use it on all ports that are host ports and not trink ports.
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amanzoorNetwork infrastructure Admin

Author

Commented:
Cheever000:
I was curious to know as I have two cisco 2960 connected and one of them show:
spanning-tree mode pvst
spanning-tree etherchannel guard misconfig
spanning-tree extend system-id

and the other cisco 2960 has only 2 lines:
spanning-tree mode pvst
spanning-tree extend system-id


So I was thinking "spanning-tree etherchannel guard misconfig" may be the problem on my netowork pertinent to not able to downoad exe files and zip files and not able to upload pdf files etc where IE freezes on uploads (sometimes very very slow, sometimes the downloads take hours example 7MB for 4 hrs and sometimes its very quick).
So I thought removing this line would solve the issue?
Help

Commented:
To disable it on a port Enter enable mode
type config t (configure terminal) to enter config mode
type int Faste 0/24 (interface FastEthernet 0/24,or gige for gigaBIT ETHERNET) to enter port confguration mode on port 24 (which is our standard port for linkingswith to switch)
Type no spanning-tree portfast

Save the configuration

Either write mem or copy run start

Commented:
spanning-tree etherchannel guard misconfig
explained here:


https://supportforums.cisco.com/message/610092

Kerem ERSOYPresident

Commented:
Hi,

Aince it is limited to some extensions and not web browsing I suspect you have a web content filter in the way blocking or speed limiting to files with certain extensions. I guess It is good to have at least one switch configured with "spanning-tree etherchannel guard misconfig".

Cheers,
K.
spanning-tree etherchannel guard misconfig

this command only affects etherchannel ports, where more then one port is bundled together for load balancing purposes.

I can't see spanning tree affecting downloads in anyway at all it is a mechanism to prevent switching loops which in turn prevents broadcast storms and the like.
amanzoorNetwork infrastructure Admin

Author

Commented:
Excellent guys:
I understand it fully now.  
Now the problem is I cannot find the 'Accept multiple solutions or accept solution' buttons on EE website anymore.  Anyone to solve this problme now :)
Regards
Kerem ERSOYPresident

Commented:
Well I've never asked a question but I've always and continuing to get split points so there must be a way. If you want you can press the request attention button and get help from a community adviser.

Cheers,
K.

Commented:
Accept an answer and see if the share buttons appear???

Commented:
no spanning-tree will disable it, but DON'T do that.

Instead remove bpdu-guard on the trunk links ("no spanning-tree bpduguard enable" under the interface) and use the features:
 - root-guard to protect the placement of the root switch
 - uplinkfast on access layer switches to allow fast recovery
 - backbonefast in the core
 - loopguard for indirect failures
amanzoorNetwork infrastructure Admin

Author

Commented:
Wooofps:
sorry szfeco: I missed your post I appologize for it.  It was hiding beneath administrative comments.
amanzoorNetwork infrastructure Admin

Author

Commented:
Thanks Guys:
For all your help!.  Really apprecaite it.

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