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Span Tree (Question)

Hi All,

Could you please explain to me the bellow output of (sh span tree vlan 805#) from my switch as follows:

Desg FWD

Boun FWD

Root FWD

Altn BLK

could you explain the meaning of (Desg,Root,Boun,Altn) ports,

Appreciate your feedback,

1 REPLY
Silver

Re: Span Tree (Question)

Designated port - it means that this port has best root path cost from the segment.

..............RootBridge

......cost2/......\ cost19

............../........\

.........RA-------X-RB

...............seg C.....

The designated port is for segment C on RA router because it has better cost to the RootBridge and the other router (RB) is in blocking state.

Root Port - the best path to the root, on every switch there is only one root port. There is one on RA and RB - which are directly connected to the RootBridge.

Alternate - If there is another link between the Root and RA, one of them are better (has lower interface number) and prefered, The prefered is the root port and the other is the alternate port. In case of failure of the root port it can function immediately as root port.

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_white_paper09186a0080094cfa.shtml#states

bye

FCS

Please rate me if I helped.

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