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spanning tree that is vlan based

Hi, still new to the cisco world. can anyone please explain spanning tree that is vlan based and provide and example if possible .. Thanks

3 REPLIES
Silver

Re: spanning tree that is vlan based

hello!

Vlan based spanning tree is nothign but PVST ( per vlan spanning tree) - cisco proprietary, or

MSTP (multiple spanning tree protocol) - 802.1s

PVST runns a spanning tree protocol instance for each vlan. Thus for each vlan, there is a set of root bridge, designated, root and blocked ports. Each vlan cvan have a different root bridge/ or different blocked link. A link blocked for 1 vlan can be made active for another vlan allowing, utilizing bandwidth optimally.

MSTP is similar to PVST but instead of running 1 spanning tree instance for each vlan, 1 instance is run for a group of vlans. So there can be multiple groups of vlans and for each group there is 1 instance again allowing utilization of links while maintaining redundancy.

The following links will give you more idea :

http://www.cisco.com/warp/public/473/147.html

http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_20_se/configuration/guide/swmstp.html

Regards,

Niranjan.

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New Member

Re: spanning tree that is vlan based

Thanks Niranjan.

So if I have one interface going from router to switch I need to creatd subinterfaces for each vlan ? assuming I need to create more then 3 vlans

Thanks

Re: spanning tree that is vlan based

alternatively, you could also configure PVRST,

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/44sg/configuration/guide/spantree.html#wp1064592

if the intention is to create routed VLANs, then yes can terminates ur vlans as sub-ifs.

anotehr way is to create SVI or routed VLANs in switch itself as long is it is supported by IOS and H/W.

HTH

Sam

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