Problems in 6509 Etherchannel

[marcospce]

Hello,

We did a rebuild of the CORE switches in our Network, now we are using 2 Catalyst 6509 with Supervisor module - SUP720.

We are using the GBIC in theses supervisor modules to build a etherchannel, between the CORES, but doing some failover tests, every time that i reload one of the CORE's, the CORE that stay's up, gets error disable in the GBIC 5/1. I did the same config of the port, using another fiber connections and didnt get this problem.

But using the uplinks in the Supervisor, i always get the problem. No matter which switch i reload, the other one gets error disable (connected to the 5/1 at the other side). This is error disable is caused by link flapping, but only after the reload.

If i shut/no shut the interface, it came abck up and remain ok.

Could someone give me a help on that ?

[sourabhagarwal]

The show logging buffer command should display error messages relating to the errdisable state.

Ports or interlaces being shut down as a result of errdisable are referred to as reasons in CatOS and causes in Cisco IOS. The reasons or causes for this happening range from EtherChannel misconfiguration causing a PAgP flap, duplex mismatch, BPDU port-guard and portfast configured at the same time, UDLD detecting a one-way link, etc.

check this URL to get more information.

http://www.cisco.com/warp/public/473/20.html

HTH ... rate if it does ...

[marcospce]

Hi, tks, for the post...

I've checked the port configuration and everything seems fine.

Also i have the same situation in another site and its working fine.

Do you guys have any other idea about that ?

[marcospce]

The problem seems that the switch that remains up, try to establish the link with the switch that is caming back up, after the reload, but the switch is not fully initialized yet, what cause the link flapping and the port status errdisable.

Does it make sense ? Is it possible to change this timer ?

[abhishek_nandavat]

Hi,

Can you paste the etherchannel config here?

Regards,

AbhisheK

[marcospce]

AT CORE 1

interface GigabitEthernet5/1

description gviac-a0-core1_g5/1

switchport

switchport trunk encapsulation dot1q

switchport trunk native vlan 50

switchport trunk allowed vlan 1,30,50,80,100-106,109,110,192,200-203,228,229

switchport trunk allowed vlan add 300,301,305,501,700-711,800-806,900-915,975

no ip address

logging event link-status

speed nonegotiate

wrr-queue bandwidth 30 70

wrr-queue queue-limit 40 30

wrr-queue random-detect min-threshold 1 40 80

wrr-queue random-detect min-threshold 2 70 80

wrr-queue random-detect max-threshold 1 80 100

wrr-queue random-detect max-threshold 2 80 100

wrr-queue cos-map 1 1 1

wrr-queue cos-map 1 2 0

wrr-queue cos-map 2 1 2 4

wrr-queue cos-map 2 2 3 6 7

mls qos trust dscp

spanning-tree guard loop

channel-group 1 mode desirable

!

interface GigabitEthernet5/2

description gviac-a0-core1_g5/2

switchport

switchport trunk encapsulation dot1q

switchport trunk native vlan 50

switchport trunk allowed vlan 1,30,50,80,100-106,109,110,192,200-203,228,229

switchport trunk allowed vlan add 300,301,305,501,700-711,800-806,900-915,975

no ip address

logging event link-status

speed nonegotiate

wrr-queue queue-limit 40 30

wrr-queue random-detect min-threshold 1 40 80

wrr-queue random-detect min-threshold 2 70 80

wrr-queue random-detect max-threshold 1 80 100

wrr-queue random-detect max-threshold 2 80 100

wrr-queue cos-map 1 1 1

wrr-queue cos-map 1 2 0

wrr-queue cos-map 2 1 2 4

wrr-queue cos-map 2 2 3 6 7

mls qos trust dscp

spanning-tree guard loop

channel-group 1 mode desirable

===========================================

AT CORE 2

interface GigabitEthernet5/1

description gviac-a0-core2_g5/1

switchport

switchport trunk encapsulation dot1q

switchport trunk native vlan 50

switchport trunk allowed vlan 1,30,50,80,100-106,109,110,192,200-203,228,229

switchport trunk allowed vlan add 300,301,305,501,700-711,800-806,900-915,975

no ip address

logging event link-status

speed nonegotiate

wrr-queue bandwidth 30 70

wrr-queue queue-limit 40 30

wrr-queue random-detect min-threshold 1 40 80

wrr-queue random-detect min-threshold 2 70 80

wrr-queue random-detect max-threshold 1 80 100

wrr-queue random-detect max-threshold 2 80 100

wrr-queue cos-map 1 1 1

wrr-queue cos-map 1 2 0

wrr-queue cos-map 2 1 2 4

wrr-queue cos-map 2 2 3 6 7

mls qos trust dscp

spanning-tree guard loop

channel-group 1 mode desirable

!

interface GigabitEthernet5/2

description gviac-a0-core2_g5/2

switchport

switchport trunk encapsulation dot1q

switchport trunk native vlan 50

switchport trunk allowed vlan 1,30,50,80,100-106,109,110,192,200-203,228,229

switchport trunk allowed vlan add 300,301,305,501,700-711,800-806,900-915,975

no ip address

logging event link-status

speed nonegotiate

wrr-queue queue-limit 40 30

wrr-queue random-detect min-threshold 1 40 80

wrr-queue random-detect min-threshold 2 70 80

wrr-queue random-detect max-threshold 1 80 100

wrr-queue random-detect max-threshold 2 80 100

wrr-queue cos-map 1 1 1

wrr-queue cos-map 1 2 0

wrr-queue cos-map 2 1 2 4

wrr-queue cos-map 2 2 3 6 7

mls qos trust dscp

spanning-tree guard loop

channel-group 1 mode desirable

[glen.grant]

Do you have anything like udld running between these interfaces , other than that you are right the config looks fine for the channel. Myself I always use the non-silent argument at the end " channel-group 1 mode desirable non-silent" . You also might try on your trunk statements "switchport mode dynamic desirable" .

[marcospce]

I have the UDLD running and the following also:

EtherChannel misconfig guard is enabled

Extended system ID is enabled

PortFast BPDU Guard Default is enabled

Loopguard Default is enabled

What about the "mode desirable non-silent" ?

What it does ?

[marcospce]

Hello Guys,

I was working with some Cisco Engineers and we found that the problem was due the no negotiate parameter into the Portchannel.

I've disable that and after this, there are no more problems.