10-05-2015 10:47 PM - edited 03-05-2019 02:27 AM
Hi Friends,
I am facing a weird issue with BGP routing in Nexus 3k (NX OS 6).
Router A (AS 6500) and B (AS 6600) are eBGP peers.
Router A:
int Eth1/1.100 (no vrf) IP 1.1.1.1 & peer 2.2.2.2
int Eth1/1.200 (vrf test) IP 10.10.10.10 & peer 20.20.20.20
Router A BGP config:
There are 2 instances of BGP running on Router A with same local & remote AS; one in global routing table and other in VRF test. The BGP adjacency comes up fine between the peers one at a time; however I have noticed that only 1 BGP session remains in "established" state at a given point of time - either the one in global routing table or the one in VRF Test. And the other one goes to Idle / Active state. If I clear BGP session for the idle/active one, it comes up and the other one goes down.
Is this normal? Or is there flaw in the design? How do I overcome this scenario?
10-06-2015 10:00 AM
Hello.
From the configuration I don't see: ebgp-multihop and update-source - this could be a reason!?
10-07-2015 12:13 PM
Hi, thanks for responding. I dont think so; however as I mentioned, one works at a time. So if it would have been an issue of reachablity, it would have never come up.
thx
10-12-2015 11:06 AM
Hi,
I had raised a Cisco TAC and understood there is a bug in Nexus for the OS used on my device. BTW, its nothing to do with BGP.
https://tools.cisco.com/bugsearch/bug/CSCuw02851
10-13-2015 01:09 AM
Hello.
could you please share your service request (SR/ticket) number?
10-15-2015 09:58 PM
Hi, here it is 636628533
10-15-2015 10:01 PM
The issue is with ACL applied to one sub-interface impacts the other sub interface (with same physical interface). So I prepared just 1 ACL, with the intersting traffic for both sub-interfaces, and applied it to both. Its working now.
I will have to manage it with this workaround until Dec 2015 end, until the OS with bug fix is released.
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