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t.k
New Member

How do I find the root port?

Is there an IOS command or CatOS command that tells me where my root port is on my switched network? I have a Cat5500 as my core switch and various Cat 3524 XL switches mixed in with some Cat 2900 & 3550's. I am certain that my root port is on my Cat 5500 but don't know which port. Any ideas? Thanks

  • Other Network Infrastructure Subjects
6 REPLIES
Silver

Re: How do I find the root port?

sh spantree

New Member

Re: How do I find the root port?

When you issue the sh spantree command the output to look at is:

Designated Root some mac address

Designated Roote Priority number

Bridge ID MAC ADDR this is the switches mac address

Bridge ID Priority this is the bridges priority

The switch that has both the same is your root bridge.

New Member

Re: How do I find the root port?

When you issue the sh spantree command the output to look at is:

Designated Root some mac address

Designated Roote Priority number

Bridge ID MAC ADDR this is the switches mac address

Bridge ID Priority this is the bridges priority

The switch that has both the same is your root bridge.

New Member

Re: How do I find the root port?

When you issue the sh spantree command the output to look at is:

Designated Root some mac address

Designated Roote Priority number

Bridge ID MAC ADDR this is the switches mac address

Bridge ID Priority this is the bridges priority

The switch that has both the same is your root bridge.

New Member

Re: How do I find the root port?

When you issue the sh spantree command the output to look at is:

Designated Root some mac address

Designated Roote Priority number

Bridge ID MAC ADDR this is the switches mac address

Bridge ID Priority this is the bridges priority

The switch that has both the same is your root bridge.

Re: How do I find the root port?

For catOS enter "show spantree vlan_#" and you can trace back via the Designated Root Port and the mac address (Designated Root) to find who is the root switch for each vlan. "Show spantree stat x/x vlan_#" is another good command.

For IOS it is "show spanning-tree".

A switch, not a port on the switch, is root for a vlan, so you won't find a specific port on the 5500. Any port that is on that vlan for which that switch is root will be considered root. On the root switch itself it will report the root port as "Designated Root Port 1/0 " (and the Designated Root and Bridge ID MAC ADDR will be the same).

Hope it helps.

Steve

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