Spantree ports both in forwarding

[wayneker]

I have a Cat5509 connected to a Cat2948G, ports 1 & 2 are port channelled as are 47 & 48. On the Cat5509 spantree says both portchannels are in forwarding, however on the 2948G spantree correctly displays that one portchannel is in blocking any ideas as to why the 5509 is not displaying the same port channel as blocked.

 

[svermill]

Is the 5509 the root?

 

[wayneker]

Yes it is the root

 

[svermill]

All ports on the root bridge must be in the forwarding state and sending BPDUs. It's up to the switches that connect to the root to break loops. In your example, there is no loop since the 2948 only has one active upstream path to the root.

 

[wayneker]

Yes that makes sense, thanks for the reply, a great help.

 

[jgercken]

Just a suggestion- Cisco has a great feature called uplinkfast that can be used on the non-root switches. Basically it will start forwarding on the blocked port immediately after detecting a link failure. (no listening-learning delay) It will also multicast it's entire mac address table over the upstream line to quickly populate the root's CAM table. STP convergence in less than a second compared to the default 30s

-Jeff ----------------------------------------
Wassabi Pop Tarts! Write Kellogs today!

 

[wayneker]

Yeah, I'm using Uplinkfast on my access switches and its superb, I also have internal Routers on the cat55509's, with MLS enabled, their is no delay at all on the routing now, and its fairly straight forward to setup aswell.