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New Member

UplinkFast/BackboneFast question?

If you are running rapid-PVST on your LAN, is uplinkfast and backbone fast necessary?

Or does rapid-PVST automatically incorporate those features into the fabric?

What are the pros/cons of using all three features, if possible?

1 ACCEPTED SOLUTION

Accepted Solutions
Bronze

Re: UplinkFast/BackboneFast question?

Hello,

Rapid spanning-tree incorporates uplinkfast, Portfast and backbonefast capability into the standard 802.1w. Therefore it is unnecessary to configure them as it's done automatically.

E.G. If a port is configured as a Point-to-Point link with rapid spanning tree, it is equivalent to configuring backbonefast

2. Edge ports are the standardised rapid spanning tree implementation of Portfast.

3. Rapid spanning tree's implementation of Uplinkfast is done automatically, and usually converges faster than Uplinkfast anyway.

Note, rapid-pvst is just Cisco's implementation of rapid spanning tree but gives you one spanning tree instance per vlan.

I hope this answers your questions.

3 REPLIES
Blue

Re: UplinkFast/BackboneFast question?

YES,

you can use uplinkFast/backboneFast with Rapid-PVST and it is still recommended where applicable.

the Rapid-PVST+ provides the following:

* rapid convergence based on 802.1w

(immediately deletes dynamically learned MAC address entries on a perPort basis upon receiving a topology change; PVST+ uses a short aging time)

* same configuration as PVST+ except that the rapid convergence is based on 802.1w, not 802.1d, plus cisco proprietary extensions.

please see the following link for more Rapid-PVST+ moode info:

http://www.cisco.com/en/US/products/hw/switches/ps5206/products_configuration_guide_chapter09186a00801ce264.html#wp1150156

please see the following link for the understanding 802.1w specification: (rapid-pvst+)

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

Bronze

Re: UplinkFast/BackboneFast question?

Hello,

Rapid spanning-tree incorporates uplinkfast, Portfast and backbonefast capability into the standard 802.1w. Therefore it is unnecessary to configure them as it's done automatically.

E.G. If a port is configured as a Point-to-Point link with rapid spanning tree, it is equivalent to configuring backbonefast

2. Edge ports are the standardised rapid spanning tree implementation of Portfast.

3. Rapid spanning tree's implementation of Uplinkfast is done automatically, and usually converges faster than Uplinkfast anyway.

Note, rapid-pvst is just Cisco's implementation of rapid spanning tree but gives you one spanning tree instance per vlan.

I hope this answers your questions.

New Member

Re: UplinkFast/BackboneFast question?

I got two conflicting answers, but I think mihanlin is correct.

Cisco wasnt too clear on that, but I just put two and two together when reading through their documentation....and I wanted to verify my findings.

Appreciated.

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