From: Huan Pham (huan.pham@valuenet.com.au)
Date: Sun Feb 03 2008 - 09:31:28 ARST
Hi,
I believe that Greg's trouble-shooting steps would fix the problem.
Just want to add more details to this common problem.
http://www.cisco.com/en/US/tech/tk389/tk213/technologies_configuration_examp
le09186a0080094647.shtml
Err-Disable State
A common issue during EtherChannel configuration is that the interfaces go
into err-disable mode. This can be seen when Etherchannel is switched to the
ON mode in one switch, and the other switch is not configured immediately.
If left in this state for a minute or so, STP on the switch where
EtherChannel is enabled thinks there is a loop. This causes the channeling
ports to be put in err-disable state. See this example for more information
on how to determine if your EtherChannel interfaces are in the err-disable
state:
%SPANTREE-2-CHNL_MISCFG: Detected loop due to etherchannel misconfiguration
of Gi0/9
%PM-4-ERR_DISABLE: channel-misconfig error detected on Po10, putting Gi0/9
in err-disable state
%PM-4-ERR_DISABLE: channel-misconfig error detected on Po10, putting Gi0/10
in err-disable stateSwitch1#show etherchannel summary
Flags: D - down P - in port-channel
I - stand-alone s - suspended
H - Hot-standby (LACP only)
R - Layer3 S - Layer2
u - unsuitable for bundling
U - in use f - failed to allocate aggregator
d - default port
Number of channel-groups in use: 1
Number of aggregators: 1
Group Port-channel Protocol Ports
------+-------------+-----------+-------------------------------------------
---- 10 Po10(SD) - Gi0/9(D) Gi0/10(D)Switch1#show interfaces GigabitEthernet 0/9 status
Port Name Status Vlan Duplex Speed Type Gi0/9 err-disabled 1 auto auto 10/100/1000BaseTX
Switch1#show interfaces GigabitEthernet 0/10 status
Port Name Status Vlan Duplex Speed Type Gi0/10 err-disabled 1 auto auto 10/100/1000BaseTX The error message states that the EtherChannel encountered a spanning tree loop. To resolve the issue, set the channel mode to desirable on both sides of the connection, and then re-enable the interfaces:
Switch1#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Switch1(config)#interface gi0/9 Switch1(config-if)#channel-group 10 mode desirable This causes each side to form a channel only if they both agree to channel. If they do not agree to channel, they continue to function as normal ports.
After the channel mode is set to desirable on both the sides of the connection, issue the shutdown and no shutdown commands on the associated interface to re-enable the ports by manually:
Switch1(config-if)#shutdown Switch1(config-if)#no shutdown
Cheers, Huan
-----Original Message----- From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Greg Wendel Sent: Sunday, 3 February 2008 3:51 AM To: ysoyibo@hotmail.com Cc: ccielab@groupstudy.com Subject: Re: Port-Channels not coming on
I have found the best way to troubleshoot this is to : 1. Verify layer 2 connections are exactly as you are expecting. 2. Delete the port channel and default the interfaces. 3. Recreate the port channels with all interfaces shutdown. 4. No shut the interfaces on both devices at the same time.
Other possibilities: Try to build the channel with mode on if PAGP or LACP are not working.
Good luck,
On Feb 1, 2008 4:17 AM, <ysoyibo@hotmail.com> wrote:
> I have set up my port channels and they are not coming up. I have made > sure that the interface setting are the same of all interfaces. Also > 'channel-group X mode on' is congfigured on all. I see err-disable on the > interfaces and the port channels not coming on. > > How can I start to troubleshoot this problem and eventually what is(are) > the probable causes of this keeping in mind what has been said earlier. > > Rgds > > Yemi > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html >
-- Gregory Wendel Springfield VA, 22153
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