[c-nsp] Port-Channel Problem

[Dan Armstrong]

I did exactly that, and managed to get it to go into LACP mode.

The Etherchannel ran for about 3 hours without a problem, then all of a 
sudden started losing pings all over the place.  I took one channel out 
of service, and it was fine.

I tested both physical links separately, and they're both perfect.  I'm 
scared to put them back into the Etherchannel now for fear that they'll 
fail again.

I am using the single fibre SFPs (the GLC-BX-Us and GLC-BX-Ds) for both 
of these links.

Anybody seen an Etherchannel lose it when the two underlying physical 
links are seemingly perfect on their own?




Collins, Richard (SNL US) wrote:
> 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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