Two Nexus 6Ks can't ping each other L3 interfaces within the same domain

[George-Sl]

Hi,

I have two Nexus 6Ks directly connected to each other through a peer link, their vpc status is UP/UP/UP, Operational, but they can't ping each others L3 interfaces(E1/1,E1/2) through the peer link.

I am quiet sure I put the right config, from Cisco documentations. Is that normal?

they can see each other Fex interfaces, but they can't see each others directly connected interfaces, and they are within the same domain.

Thx

[rdz586]

Hi George,

Could it be CoPP blocking ICMP traffic?

https://community.cisco.com/t5/networking-documents/icmp-ping-drops-when-pinging-from-nexus-7000/ta-p/3125996

[Reza Sharifi]

Hi,

That is not normal. Can you post configs from both 6ks? 

HTH

[George-Sl]

This config is from the switch to the left

Dual Homed Enhanced VPC

int mgmt0
ip add 10.151.1.6 255.255.255.252


feature vpc
feature LACP
vpc domain 1
Peer-switch
peer-keepalive destination 10.151.1.5 source 10.151.1.6 vrf management
ip arp synchronize


int e1/47-48
no shut
sw mode trunk
channel-group 1 mode ac
int po1
no sh
swi mode trunk
swi trunk allowed vlan all
vpc peer-link


fex 101
int eth1/1
channel-group 101   ///it's a single member port channel
interface po101
switchport mode fex-fabric
vpc 101
fex associate 101


fex 102
int eth1/2
channel-group 102
interface po102
switchport mode fex-fabric
vpc 102
fex associate 102

[Reza Sharifi]

fex 101
int eth1/1
channel-group 101   ///it's a single member port channel
interface po101
switchport mode fex-fabric
vpc 101
fex associate 101

Do you have the same exact config on the other switch? Since your FEXs are dual homed to both 6ks, you need the same exact config on both switches. Also, is OSPF peering up and running between the 6k and the 9500? What IP are you pinging?

What is the output of "sh ip route" from the 6ks?

HTH

[George-Sl]

Same config on both switches,

even that this should have nothing to do with the routing and routing protocols because two 6Ks are directly connected to each other via the Peer links and they are on a same domain and they supposed to be a one logical device or idk, but OSPF is ON on all SVIs and L3 interfaces(which is only one interface in this case), this is how the ping traces through.

and if I disconnect the uplink to the 9500, the ping won't go through at all.

from the left 6K I pinged the ethernet1/25 which is 10.150.100.1

this is the routing table on right one

Routing table of the left one

thx a lot

[Reza Sharifi]

Hi,

e1/25 is a layer-3 interface with no vlan configuration and that is why when you disconnect the uplink to the 9500, you can't ping IP 10.150.100.1 on the right side.  If you want to use the vPC peer link to send ICMP traffic, you need to create an SVI for one of the vlan that is on the vPC peer link(1900, 2000 or 2100), give each side an IP and than try and ping.

HTH