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L3 issues between ASW and Nexus when a VPC is down

geeksy
Level 1
Level 1

Hello,

Hope some can help and identify an issue I am facing. Below is my lab topology in GNS3, using nxsosv-9k-7.0.3.16.2 image.

 

ASW has links to NXS1 and NXS2 in a port channel. Everything works fine in the normal scenario, I can ping both NXS and HSRP. When I fail one of the link, from NXS1 to ASW, I cannot ping NXS2 or the HSRP IP but odd, I can ping NXS1. In the failure scenario, the only path for ASW is via NXS2, so unsure why I can't ping it but can ping NXS1 over vpc peer link.

 

ciscosup.JPG

 

Before the failure, MAC address table of ASW shows path for NXS1 & HSRP via Gi0/1. After the failure, it correctly updates the MAC table to Gi0/0 for all three IPs. So unsure what the issue and what I am doing wrong.

 

Any help is highly appreciated, all configs and outputs attached. Thanks in advance.

 

==========Ping ARP and MAC table on ASW==========

Switch#ping 192.168.1.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 10/11/14 ms

Switch#ping 192.168.1.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.3, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

Switch#ping 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

Switch#sh ip arp
Protocol Address Age (min) Hardware Addr Type Interface
Internet 192.168.1.1 2 0000.0c07.ac05 ARPA Vlan30
Internet 192.168.1.2 10 5005.0001.0007 ARPA Vlan30
Internet 192.168.1.3 10 5005.0002.0007 ARPA Vlan30
Internet 192.168.1.254 - 5005.0003.801e ARPA Vlan30

Switch#sh mac address-table
Mac Address Table
-------------------------------------------

Vlan Mac Address Type Ports
---- ----------- -------- -----
30 0000.0c07.ac05 DYNAMIC Gi0/0
30 5005.0001.0007 DYNAMIC Gi0/0
30 5005.0002.0007 DYNAMIC Gi0/0
Total Mac Addresses for this criterion: 3
Switch#

1 Reply 1

geeksy
Level 1
Level 1

Issue resolved.

 

Since this was GNS3 lab, even though NXS1 interface to ASW is shutdown, ASW still has its interface up. I shut the Gi1 on ASW and everything works fine as expected. Not entirely sure why it didn't work in the first place even though MAC table appears correct though.

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