Changing VLANs
I have a small network (5 24 port cisco 3550s). Currently I am experiancing a lot of network congestion on one of the switches which I will be taking care of this weekend. Howerver, while researching this problem I noticed it causing other problems. Namely it is mucking up Spanning Tree Protocol.
When i did my research in to STP I found many articles saying that it was a bad thing to leave all the swtich ports in VLAN1 as this would add traffic to the cpu and could cause a loss of BPDU's which would break STP. My busiest swiitch is reporting RTD-1-ADDR_FLAP messages (lots of them) I am guessing that STP is being effected by the HIGH network traffic.
So my question is should I move all my switch ports to another VLAN? And how hard is this? We do not use VLAN's here and I really do not see a need for them here except for cases like this. The other thing mentioned is that with the newer IOS's you can remove VLAN1 (some how). I do have the newest IOS installed on all my switches so I should be able to do this too. Is this a good solution or is moving every thing to another VLAN better?
Thanks,
Louis
When i did my research in to STP I found many articles saying that it was a bad thing to leave all the swtich ports in VLAN1 as this would add traffic to the cpu and could cause a loss of BPDU's which would break STP. My busiest swiitch is reporting RTD-1-ADDR_FLAP messages (lots of them) I am guessing that STP is being effected by the HIGH network traffic.
So my question is should I move all my switch ports to another VLAN? And how hard is this? We do not use VLAN's here and I really do not see a need for them here except for cases like this. The other thing mentioned is that with the newer IOS's you can remove VLAN1 (some how). I do have the newest IOS installed on all my switches so I should be able to do this too. Is this a good solution or is moving every thing to another VLAN better?
Thanks,
Louis
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Before you think of turning STP off take warning that one of it's main functions is to detect and prevent Loops in your network. The Flapping you mentioned happens when a loop is detected. If you turn off STP and there is a loop that it is preventing...then your network will "break".
Take a good hard look at how your network is wired and try to eliminate and loops to resolve the problem before turning this off.
to view the status of spanning tree in enable mode do: sh spanning
For the sake of you users turn this off after-hours.
in config t mode simply type: no span
to view the status of spanning tree in enable mode do: sh spanning
If you don't like the delay in a connection becoming active, you can always use the portfast spanning tree option on ports you are sure will never cause a loop (such as end-user PCs)
Take a good hard look at how your network is wired and try to eliminate and loops to resolve the problem before turning this off.
to view the status of spanning tree in enable mode do: sh spanning
For the sake of you users turn this off after-hours.
in config t mode simply type: no span
to view the status of spanning tree in enable mode do: sh spanning
If you don't like the delay in a connection becoming active, you can always use the portfast spanning tree option on ports you are sure will never cause a loop (such as end-user PCs)
ASKER
I had to do some network work this weekend and on of the things I did do was reboot all my switches. When they came up I did not get that flapping message. And even now I am not seeing it. So maybe there was a eccessive amount of traffic causing this problem and not a loop.
As long as I do not see a problem I will not touch STP.
Louis
As long as I do not see a problem I will not touch STP.
Louis
>As long as I do not see a problem I will not touch STP.
Good idea!
Keeping fingers crossed!!!
Good idea!
Keeping fingers crossed!!!
ASKER
Thanks every one for your help.
Louis
Louis
ASKER
But how do I turn it off?????? I did some searches and did not find the answer.
Louis