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New Member

root guard feature


I have to 2 distribution switch running HSRP;These distribution switchs(6509sup1) connected to the core switchs(6509sup20)via L3 Link.Also the 1 dist act as primary root bridge and the 2 dist act as second root where i need to configure The root guard feature?

simple config very much Appreciated.

10xs for ur time to helpe me out.


Re: root guard feature

if you have your dist bridges set as your root bridge(s), then you'll configure rootGuard on those DesignatedPort(s) of the switches connected to your dist bridges. (of those switches you DO NOT want to become the rootBridge)

rootGuard ensures that the port that rootGuard is configured on is the DesignatedPort.

rootGuard is configured on a per-Port basis.

you should configure rootGuard on all ports that the rootBridge should NOT appear.

see this link for more info:

Re: root guard feature

You can ignore the L3 links, where stp is not run (well, you can configure rootguard on them if you want, it will not do anything).

You have to be careful with rootguard as it will limit the ability to change elect a new root port on a bridge in case of failure of the root port.

Now, coming back to your particular case, you forgot to mention how the two distribution bridges were connected at layer 2. Is there a direct link between them or can they only see each other through some access bridges?

Generally, there is some redundant links between them the distribution. Rootguard is then configured to prevent using an access switch as a backup in case of failure of these redundant links (the inter-distribution traffic is important, and you'd rather keep your network partitioned rather that switching 30gig of traffic throug a 2900XL;-) for instance).

So basically, you can configure rootguard on the port of your distribution switch that you never want to be used as an alternate path between the distribution switches. As far as the config is concerned, there is nothing much: just enable rootguard on the interfaces;-)



New Member

Re: root guard feature

Hi Friend!

u mean to just enable rootguard on All the interfaces;(l3;l2) Link.regards to link between the Dist;its Etherchanel.what is the command to enable rootguard?


New Member

Re: root guard feature


Thank u.the command is "spanning-tree rootguard"


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