UplinkFast and BackboneFast (STP)

[Jerome Vidal]

Hi folks,

When I setup STP on a switched environment with UplinkFast, would there be any foreseeable problem when I implement BackboneFast in conjuction with it? I haven't seen any docs suggesting UplinkFast + BackboneFast should not be implemented at once.

Any thoughts would be appreciated.

[paul driver · Accepted solution]

Hello

No there wont be, Uplinkfast works on directly connected links, Backbonefast detects indirectly links failures on other switches.

res
Paul

[Jerome Vidal]

Thank you Paul! That's what I wanted to hear!

Can I ask one more question on STP? As we all know, RSTP can be enabled using the command spanning-tree mode rapid-pvst, it appears that this command is also related to PVST.Could you confirm if they're actually just the same somehow? In exactly what way do they differ? PVST makes STP very confusing.

[Joseph W. Doherty]

Rapid-STP is a much better version than STP, and should be used, if supported.  It also already has stuff like uplinkfast and backbonefast built-in.

Per VLAN STP, or the rapid variant, runs an instance of STP per each VLAN rather than running one instance for all VLANs.  The advantage of this, you may have different STP topologies per VLAN.  It's most useful when you have redundant paths.  STP shuts all redundant paths, but with per VLAN STP, you can control what links are used per VLAN.  This allows you to use all your redundant paths, by having some VLANs use each.

BTW, MST runs an instances of STP where you select which VLANs are in them.  The advantage of this, if your network only had two redundant paths, for example for 10 VLANs, you would only need to run two STP instances to take advantage of both redundant paths, which you could not do with common STP yet not need to run 10 instances of STP as per VLAN STP would do.