Etherchannel L3 issue

[Clement BONNAL]

Hello,

I want to connect two VSS pairs through a 4*10GB L3 Etherchannel.

When I put IP Address directly on the port, through one link, it works.

But when I do config on the Po, and I put the port into the Po it doesn't work (I cannot ping dest Po virtual interface from local VSS)

Here is the config :

VSS 1 :

interface TenGigabitEthernet2/2/1
 no switchport
 no ip address
 channel-group 42 mode on

!

interface Port-channel42
 no switchport
 ip address 172.17.121.66 255.255.255.254

VSS-DC-01#show etherchannel summary

Group  Port-channel  Protocol    Ports
------+-------------+-----------+-----------------------------------------------
42     Po42(RU)         -        Te2/2/1(P)

VSS 2 :
interface TenGigabitEthernet1/8/1
 no switchport
 no ip address
 channel-group 42 mode on
!
interface Port-channel42
 no switchport
 ip address 172.17.121.67 255.255.255.254

R-FERG01#show etherc summ
Group  Port-channel  Protocol    Ports
------+-------------+-----------+-----------------------------------------------
42     Po42(RU)         -        Te1/8/1(P)

So :

- the Po is OK

- the network is in the routing table as "directly connected"

- the remote VSS is visible as cdp neighbor

- the ping doesn't works

Can you tell me what's wrong ?

Equipment is :

6509 with SUP720 v12.2(33)SXJ2
CEF720 8 port 10GE with DFC  WS-X6708-10GE

Thank you very much

[Philip D'Ath]

I don't believe there is anything wrong with your configuration.  Can you upgrade to a gold star release like 15.1.2-SY7 ?

https://software.cisco.com/download/release.html?mdfid=281569550&catid=268437717&softwareid=280805680&release=15.1.2-SY7&relind=AVAILABLE&rellifecycle=MD&reltype=latest

[Clement BONNAL]

Hello,

I just make a capture on the portchannel, and what I can see is following :

- I can see an ARP Request going on the Po interface, but without answer.
- On the other side, I never see the ARP request coming in ....

So mac address table display incomplete ARP entry for dest Po IP Address.

Another discussion refers to very similar problem but without correct answer : https://supportforums.cisco.com/discussion/10909781/vss-pair-vss-pair-mec-ip-communication-not-working

Can you help me ?

[Peter Koltl]

We are experiencing a bug-suspect behavior if the SFP is inserted or replaced after applying the port config. Please try to use a different port, first insert the SFP, then configure the port.

[carlos.hernandez]

Did you find an answer to your issue?

I've just experienced the exact issue with a pair of 4507-r in VSS mode to another pair of 4500-x in VSS mode L3 etherchannel. Configured LACP as well as PagP and same issue not able to ping between each other. 

thanks,
Carlos

[lauresfrank]

Did you ever find a solution? Same Problem here when conntecting 2x 4506e sup8 vss systems(4chassis) sw 3.6.7 with l3 etherchannel Mode on. 10g-lr sfps.  Lacp active active on both sides unsuccessfull because neighbor not sees lacp messages.  Maybe this is related to the problem. Cdp works and sees correct neighbors.