C9500 interface suspended

[M_Neman]

Hi all,

i have a simple question which couldnt find any answer googling.

access Switch (2960x)                                Distribution Switch (C9500)

Gi1/049 Gi 1/0/50 (member of Po1)            Twe1/0/10 Twe2/0/10 (member of Po10)

Interface Twe2/0/10 is not connected but the interface Twe1/0/10 on Distribution Switch goes to suspended state, nothing shows in logs. only after shut/no shut, link up/down syslog messages.

how do i find the reason why the interface is being put in suspended state ? i just want to know the reason behind it.

i dont have console access to the access switch at the moment so i cant check on that side.

Thanks,

[Chris McCann]

Hi M

Which model C9500 is it, I dont think all of them support 1GB.

regards,

Chris.

[M_Neman]

sorry my mistake. the access switch (WS-C2960X-48LPD-L) has also two 10Gig uplink interfaces. so both sides are connected using 10Gig links.

xyz#show int TwentyFiveGigE1/0/10 status

Port Name Status Vlan Duplex Speed Type
Twe1/0/10 xyzt Te1 suspended trunk full 10G SFP-10GBase-LRM

the access switch was deinstalled because of a maintenance couple months ago but no change in config, now it has been powered on again, it might be cabling error, but at least i should see on Distribution switch a reason why the interface is suspended but i dont.

i run an "debug lacp packets" on Distribution switch and see that the lacp pdus are exchanged but nothing related to suspending.

001891: May 21 12:30:39.078 MESZ: LACP: col-tlv:3, col-tlv-len:16, col-max-d:0x8000
001892: May 21 12:30:39.078 MESZ: LACP: term-tlv:0 termr-tlv-len:0
001893: May 21 12:30:39.078 MESZ: LACP :lacp_bugpak: Send LACP-PDU packet via Twe1/0/10
001894: May 21 12:30:39.078 MESZ: LACP : packet size: 124
001895: May 21 12:30:39.078 MESZ: LACP: pdu: subtype: 1, version: 1
001896: May 21 12:30:39.078 MESZ: LACP: Act: tlv:1, tlv-len:20, key:0xA, p-pri:0x8000, p:0x30B, p-state:0x5,
s-pri:0x8000, s-mac:MAC
001897: May 21 12:30:39.078 MESZ: LACP: Part: tlv:2, tlv-len:20, key:0x1, p-pri:0x8000, p:0x134, p-state:0x1,
s-pri:0x8000, s-mac:MAC
001898: May 21 12:30:39.078 MESZ: LACP: col-tlv:3, col-tlv-len:16, col-max-d:0x8000
001899: May 21 12:30:39.078 MESZ: LACP: term-tlv:0 termr-tlv-len:0
001900: May 21 12:30:39.080 MESZ: LACP :lacp_bugpak: Receive LACP-PDU packet via Twe1/0/10
001901: May 21 12:30:39.080 MESZ: LACP : packet size: 124
001902: May 21 12:30:39.080 MESZ: LACP: pdu: subtype: 1, version: 1
001903: May 21 12:30:39.080 MESZ: LACP: Act: tlv:1, tlv-len:20, key:0x1, p-pri:0x8000, p:0x134, p-state:0x85,
s-pri:0x8000, s-mac:MAC
001904: May 21 12:30:39.080 MESZ: LACP: Part: tlv:2, tlv-len:20, key:0xA, p-pri:0x8000, p:0x30B, p-state:0x86,
s-pri:0x8000, s-mac:MAC

Thanks,

[klnnnnng]

Hi,

did you try with "show log | inc suspended" ?

[M_Neman]

yes i did, even i read line by line without filter, nothing is there

do you know any command which tells me the reason ? or do you if need to enable any specific logging under Physical interface or Port-channel beside "logging event trunk-status" and "logging event link-status" and "logging event bundle-status" under port channel config ?

Thanks,

[klnnnnng]

Interesting, so on both Distribution and Access sides you don't see any logs regarding the suspended interface?

Could be something like UDLD, but should appear in the logs.

[M_Neman]

I don't have access to access switch at the moment because of this problem.

But as said I don't see anything on distribution switch.

[Richard Burts]

Not sure if it is accurate, but taking things at face value I note that 2960 indicates membership in  Po1 while 9500 indicates membership in  Po10.

[M_Neman]

yes correct, on 2960 side the portchannel number is 1 and on 9500 10, it should not be a problem correct ? because portchannel numbers are local to switch and we have couple thousands of access switches with same design.

by the way, do you remember any command / debug which can at least give me a hint why the interface is being suspended ?

[klnnnnng]

What happens when you remove the Port-Channel configuration and go back to normal trunk port? Maybe the configuration was not saved when powering off the access switch.

[M_Neman · Accepted solution]

Thanks all, we found the problem and it was because of cabling error. onsite team mistakenly connected cable from another switch part of another port channel to the port which was being suspended. but magically, i don't see any syslog messages eighter on access switch nor on distribution switch. 

[Chris McCann]

oppsss....

These things happen to all of us.

Chris.

[Richard Burts]

Thanks for the update. Glad to know that you have found the solution to your problem.