[c-nsp] Port-Channel Problem

Collins, Richard (SNL US) rich.collins at siemens.com
Tue May 8 16:48:07 EDT 2007


So I suppose the opposite side was set at the same time to either
channel-group 10 mode [active or passive] for LACP?

What about additionally setting..
metro2.tor-Front[760(config-if)#channel-protocol lacp 
I can't test this myself but saw the configuration option.

-Rich


>Date: Sat, 05 May 2007 02:39:04 -0400
>From: Dan Armstrong <dan at beanfield.com>
>Subject: [c-nsp] Port-Channel Problem
>To: cisco-nsp at puck.nether.net
>Message-ID: <463C2688.8060909 at beanfield.com>
>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
>Riddle me this.
>
>I have 1 physical link, and a port-channel interface operating in PAgP
mode.
>
>interface GigabitEthernet1/21
>no ip address
> switchport
> switchport trunk encapsulation dot1q
> switchport trunk allowed vlan
50,80,119,300-304,349,412,420,440,444,446,447
> switchport trunk allowed vlan add 449,500,503,616,620,900
> switchport mode trunk
> channel-group 10 mode desirable
>end
>
>interface Port-channel10
> no ip address
> switchport
> switchport trunk encapsulation dot1q
> switchport trunk allowed vlan
50,80,119,300-304,349,412,420,440,444,446,447
> switchport trunk allowed vlan add 449,500,503,616,620,900
> switchport mode trunk
>
>
>metro2.tor-Front[7609]#sh int po10
>Port-channel10 is up, line protocol is up (connected)
>  Hardware is EtherChannel, address is 0015.f91d.5c8e (bia
0015.f91d.5c8e)
>  Description: GEC to metro1.tor-Mowat [Port-channel10]
>  MTU 9216 bytes, BW 1000000 Kbit, DLY 10 usec,
>     reliability 255/255, txload 104/255, rxload 202/255
>
>
>Life was good, then:
>
>
>2 problems.  I first tried to change to LACP:
>
>metro2.tor-Front[760(config-if)#channel-group 10 mode ?
>  active     Enable LACP unconditionally
>  auto       Enable PAgP only if a PAgP device is detected
>  desirable  Enable PAgP unconditionally
>  on         Enable Etherchannel only
>  passive    Enable LACP only if a LACP device is detected
>
>metro2.tor-Front[760(config-if)#channel-group 10 mode active
>
>
>The interface bounced, and went straight back into PAgP mode..... 
>
>I tried it several times.  #$S%E$@#$, always back to PAgP..... 
>"channel-group 10 mode desirable"
>
>
>Second problem:
>
>I tried a second link anyway, and when I added a second link into the 
>PAgP group, the rely on the port-channel interface started dropping
like 
>a stone,  packets were dropping all over the place and even though 
>everything seemed to be up, speed, duplex, vlans, configuration 
>perfectly matched between the underlying physical interfaces & the 
>port-channel interface.... the po interface was a mess.  The new 
>physical link on it's own is clean as a whistle when I setup a test 
>vlan, or set both sides up as routed interfaces....
>
>Anybody have any light to shed?
>



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