[c-nsp] Cat4900M bundle problems

[Dmitry Kiselev]

Hello!

I have see strange flaps on bundle/aggregation logic on Cat4900M platform.
>From time to time one, several or all ports left the bundle without any reasons
and then in short period of time join it again. I see this on about ten almost
identical 4900 boxes (IOS/modules) with few times per dey frequency. While unbundle
ports does not went down - no syslog records neigher from 4900M, nor from remote
side. Bundle control protocol on some links is LACP, but on others - "none/forced on".
Another thing - te1/1-te1/8 on all boxes seems does not affected, only ports
on modules 2 and 3 flapped. No matter which kind of module installed 4920 or 4908.
remote devices are various models/vendors, in some cases it made by Cisco too :) 

09:46:26.529: %EC-5-UNBUNDLE: Interface GigabitEthernet2/16 left the port-channel Port-channel2
09:46:26.537: %EC-5-UNBUNDLE: Interface GigabitEthernet2/15 left the port-channel Port-channel2
09:46:26.541: %EC-5-UNBUNDLE: Interface GigabitEthernet2/10 left the port-channel Port-channel1
09:46:26.549: %EC-5-UNBUNDLE: Interface GigabitEthernet2/9 left the port-channel Port-channel1
09:47:13.795: %EC-5-BUNDLE: Interface GigabitEthernet2/9 joined port-channel Port-channel1
09:47:13.811: %EC-5-BUNDLE: Interface GigabitEthernet2/10 joined port-channel Port-channel1
09:47:13.819: %EC-5-BUNDLE: Interface GigabitEthernet2/15 joined port-channel Port-channel2
09:47:13.855: %EC-5-BUNDLE: Interface GigabitEthernet2/16 joined port-channel Port-channel2
...
11:31:20.148: %EC-5-UNBUNDLE: Interface Te3/3 left the port-channel Po3
11:32:14.390: %EC-5-BUNDLE: Interface Te3/3 joined port-channel Po3

Port actually stops forwarding traffic (it is clearly seen with stats collected via snmp),
not just reporing.

IOSes: 12.2(54)SG, 12.2(53)SG2

Cuts from config - it is very simple:

interface GigabitEthernet2/9
 switchport access vlan XXX
 switchport mode access
 channel-group 1 mode on

interface TenGigabitEthernet3/3
 switchport mode trunk
 channel-group 3 mode active

Group  Port-channel  Protocol    Ports
------+-------------+-----------+--------------------------------
1      Po3(SU)          -        Gi2/9(P)    Gi2/10(P)
3      Po3(SU)         LACP      Te3/1(P)    Te3/3(P)    Te3/5(P)
                                 Te3/7(P)


Does somebody see similar issue? Any ides how to fix it without touching the TAC?
Thanks!

-- 
Dmitry Kiselev