09-25-2017 09:55 AM - edited 03-08-2019 12:09 PM
Hello, I have a lab environment with a layer 3 (3850) switch that has a port-channel with a layer 2 4506. What i'm seeing in the logs is a port drops off, then users come over saying they have lost their remote session into the lab:
Sep 25 09:46:22: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/3, changed state to up
Sep 25 10:28:51: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/3, changed state to down
Sep 25 10:28:58: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/3, changed state to up
My config on the 3850 is:
interface GigabitEthernet1/0/3 switchport mode trunk channel-group 2 mode active end Lab#sho run int gi 1/0/4 Building configuration... Current configuration : 90 bytes ! interface GigabitEthernet1/0/4 switchport mode trunk channel-group 2 mode active end
and on the 4506:
interface GigabitEthernet2/1 switchport trunk encapsulation dot1q switchport mode trunk logging event link-status logging event trunk-status channel-group 2 mode active end 4506swa-04#sho run int gi 2/2 Building configuration... Current configuration : 181 bytes ! interface GigabitEthernet2/2 switchport trunk encapsulation dot1q switchport mode trunk logging event link-status logging event trunk-status channel-group 2 mode active end
The network outage is minimal, but enough to kill the remote sessions. I have replaced the cable and there are no errors on the interfaces. Why is there an outage with a 2 port channel when 1 port goes down?
Thanks for any advice.
Solved! Go to Solution.
09-26-2017 11:57 AM
Hello,
on a side note, you might want to try and configure:
no port-channel standalone-disable
on your port channel interfaces (if your IOS supports it). This basically prevents the entire channel from going down when one side becomes unresponsive...
09-26-2017 12:12 AM
Hello
Are both physcail interfaces in a up/up state?
Have you tried changing the cabling/ports and recreating the PC .
Can you post -
Show etherchannel summary
show etherchannel port-channel
res
Paul
res
Paul
09-26-2017 12:24 AM
Try changing the negotiation protocol used for establishing the port-channel.
In your case you are using LACP as indicated by the word "active" at the end of "channel-group 2 mode active"
Try using PaGP (Cisco Proprietary) - keyword is "desirable"
If this doesn't improve things, turn off negotiation protocol altogether by using keyword "on".
Also, perform a "shutdown" on the interface before changing the ocnfiguration, this tends to flush out any errors and such, once you're happy, issue a "no shutdown" to bring it back up.
Best of luck, keep us posted.
09-26-2017 08:04 AM
Show Etherchannel Summary on 4506:
Number of channel-groups in use: 2 Number of aggregators: 2 Group Port-channel Protocol Ports ------+-------------+-----------+----------------------------------------------- 1 Po1(SD) - 2 Po2(SU) LACP Gi2/1(P) Gi2/2(P)
Show Etherchannel Summary on 4506:
Channel-group listing: ---------------------- Group: 1 ---------- Port-channels in the group: --------------------------- Port-channel: Po1 ------------ Age of the Port-channel = 313d:22h:43m:01s Logical slot/port = 11/1 Number of ports = 0 GC = 0x00000000 Port state = Port-channel Ag-Not-Inuse Protocol = - Port security = Disabled Group: 2 ---------- Port-channels in the group: --------------------------- Port-channel: Po2 (Primary Aggregator) ------------ Age of the Port-channel = 313d:22h:43m:04s Logical slot/port = 11/2 Number of ports = 2 Port state = Port-channel Ag-Inuse Protocol = LACP Port security = Disabled Ports in the Port-channel: Index Load Port EC state No of bits ------+------+------+------------------+----------- 1 00 Gi2/1 Active 0 0 00 Gi2/2 Active 0 Time since last port bundled: 0d:08h:14m:16s Gi2/1 Time since last port Un-bundled: 0d:08h:14m:23s Gi2/1
Show Etherchannel Summary on 3850:
Number of channel-groups in use: 2 Number of aggregators: 2 Group Port-channel Protocol Ports ------+-------------+-----------+----------------------------------------------- 1 Po1(RU) LACP Gi1/0/1(P) Gi1/0/2(P) 2 Po2(SU) LACP Gi1/0/3(P) Gi1/0/4(P)
show etherchannel port-channel on 3850:
Group: 1 ---------- Port-channels in the group: --------------------------- Port-channel: Po1 (Primary Aggregator) ------------ Age of the Port-channel = 44d:22h:47m:50s Logical slot/port = 12/1 Number of ports = 2 HotStandBy port = null Passive port list = Gi1/0/1 Gi1/0/2 Port state = Port-channel L3-Ag Ag-Inuse Protocol = LACP Port security = Disabled Ports in the Port-channel: Index Load Port EC state No of bits ------+------+------+------------------+----------- 0 00 Gi1/0/1 Active 0 0 00 Gi1/0/2 Active 0 Time since last port bundled: 44d:22h:22m:18s Gi1/0/2 Time since last port Un-bundled: 44d:22h:40m:41s Gi1/0/1 Group: 2 ---------- Port-channels in the group: --------------------------- Port-channel: Po2 (Primary Aggregator) ------------ Age of the Port-channel = 44d:22h:47m:50s Logical slot/port = 12/2 Number of ports = 2 HotStandBy port = null Port state = Port-channel Ag-Inuse Protocol = LACP Port security = Disabled Ports in the Port-channel: Index Load Port EC state No of bits ------+------+------+------------------+----------- 0 00 Gi1/0/3 Active 0 0 00 Gi1/0/4 Active 0 Time since last port bundled: 0d:08h:16m:42s Gi1/0/4 Time since last port Un-bundled: 0d:08h:16m:46s Gi1/0/4
Thanks
09-26-2017 09:44 AM
Hi
Your configuration looks fine, have you tried to replace the SFP (if apply) also check the speed and duplex. Or try to use other ports.
09-26-2017 11:09 AM
The Duplex and Speed look good. They are copper cables. I can try and use a different port and see if that helps.
09-26-2017 11:57 AM
Hello,
on a side note, you might want to try and configure:
no port-channel standalone-disable
on your port channel interfaces (if your IOS supports it). This basically prevents the entire channel from going down when one side becomes unresponsive...
10-03-2017 08:28 AM
This command:
no port-channel standalone-disable
does seem to keep the port-channel up. Thanks! Now i just need to see why the interface is getting over subscribed.
Thanks for the help
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