[c-nsp] Etherchannel guard vs. mstp

[Nemeth Laszlo]

Dear List,

I have 6500/SUP720-3BXL with ipservicesk9-mz.122-18.SXF13.bin (this is 
Router A) , a 7600/RSP720-3CXL with advipservicesk9-mz.122-33.SRC3.bin 
(this is Router B), and a Router C 6500/3BXL with 
ipservicesk9-mz.122-18.SXF6.bin.

The topology is:

Router A  == 4x10G (lacp) ==  Router B  == 2x10G (pagp) ==  Router C


All routers run Rapid-PVSTP.

I needed to change the STP from RSTP to MSTP on all devices.

The first router was the Router A. It changed without problem.
But when i sent the "spanning-tree mode mstp" to Router B it put down 
the 4x10G Etherchannel link with Router A and logged it:

Mar  9 16:04:57.669 MET: %PM-SP-STDBY-4-ERR_DISABLE: channel-misconfig 
error detected on Te1/3, putting Te1/3 in err-disable state
Mar  9 16:04:57.677 MET: %PM-SP-STDBY-4-ERR_DISABLE: channel-misconfig 
error detected on Te1/4, putting Te1/4 in err-disable state
Mar  9 16:04:57.685 MET: %PM-SP-STDBY-4-ERR_DISABLE: channel-misconfig 
error detected on Te2/3, putting Te2/3 in err-disable state
Mar  9 16:04:57.701 MET: %PM-SP-STDBY-4-ERR_DISABLE: channel-misconfig 
error detected on Te2/4, putting Te2/4 in err-disable state

Mar  9 16:04:57.641 MET: %PM-SP-4-ERR_DISABLE: channel-misconfig error 
detected on Po3, putting Te1/3 in err-disable state
Mar  9 16:04:57.653 MET: %PM-SP-4-ERR_DISABLE: channel-misconfig error 
detected on Po3, putting Te1/4 in err-disable state
Mar  9 16:04:57.665 MET: %PM-SP-4-ERR_DISABLE: channel-misconfig error 
detected on Po3, putting Te2/3 in err-disable state
Mar  9 16:04:57.673 MET: %PM-SP-4-ERR_DISABLE: channel-misconfig error 
detected on Po3, putting Te2/4 in err-disable state
Mar  9 16:04:57.685 MET: %PM-SP-4-ERR_DISABLE: channel-misconfig error 
detected on Po3, putting Po3 in err-disable state


The Etherchannel with Router C stilled UP only the Router A went down.

If i deleted and recreated the port channel with LACP or PAGP or other 
etherchannel number, the result always it: put down the links.

If i changed back to RSTP on the Router B, all links went UP with router 
A and it's working without problem.

So the topology now is: Router A runs MSTP, router B runs RSTP and 
router C runs  RSTP too.

I think the STP's etherchannel guard put down the link, but i don't 
found any bug that made this problem in the BugTool at Cisco.com.

Any idea?

Thanks

Laszlo