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Cisco Bug: CSCvs34336 - VXLAN VLANs suspended post-ISSU after reloading a vPC peer

Last Modified

Sep 02, 2020

Products (59)

  • Cisco Nexus 9000 Series Switches
  • Cisco Nexus 3548-X Switch
  • Cisco Nexus 9516 Switch
  • Cisco Nexus 3548 Switch
  • Cisco Nexus 92348GC-X Switch
  • Cisco Nexus 3636C-R Switch
  • Cisco Nexus 3064 Switch
  • Cisco Nexus 93108TC-FX Switch
  • Cisco Nexus 31108TC-V Switch
  • Cisco Nexus 92160YC-X Switch
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Known Affected Releases

9.3(1) 9.3(2.20)

Description (partial)

Symptom:
Consider a scenario where two Nexus 9000 devices are in a vPC domain acting as leafs in a VXLAN BGP EVPN fabric where one of the Nexus 9000 devices is reloaded. After the reloaded devices comes back online, both vPC peers will suspend some VLANs from the vPC Peer-Link due to a Type 1 Compatibility Check failure:

N9K-1# show logging logfile | include ignore-case suspend
2020 May 12 11:21:05.665 N9K-1 %ETHPORT-3-IF_ERROR_VLANS_SUSPENDED: VLANs 10,20,30,40-50,100 on Interface port-channel1 are being suspended. (Reason: Global compat check failed)

N9K-2# show logging logfile | include ignore-case suspend
2020 May 12 11:21:04.397 N9K-2 %ETHPORT-3-IF_ERROR_VLANS_SUSPENDED: VLANs 10,20,30,40-50,100 on Interface port-channel1 are being suspended. (Reason: Global compat check failed)

Specifically, the Nexus 9000 device that was not reloaded will report that its multidestination traffic replication method is set to "multicast", even though it is configured for BGP EVPN Ingress Replication.

N9K-2# show vpc consistency-parameters vni 
<snip>
    Legend:
        Type 1 : vPC will be suspended in case of mismatch

Name                        Type  Local Value            Peer Value             
-------------               ----  ---------------------- -----------------------
Nve1 Vni, Mcast, Mode,      1     100010, 0.0.0.0,       100010, 0.0.0.0,      
Type, Flags                       UcastBGP, L2, None     Mcast, L2, None       
Nve1 Vni, Mcast, Mode,      1     100020, 0.0.0.0,       100020, 0.0.0.0,      
Type, Flags                       UcastBGP, L2, None     Mcast, L2, None       
Nve1 Vni, Mcast, Mode,      1     100030, 0.0.0.0,       100030, 0.0.0.0,      
Type, Flags                       UcastBGP, L2, None     Mcast, L2, None  

N9K-1# show vpc consistency-parameters vni 
<snip>
    Legend:
        Type 1 : vPC will be suspended in case of mismatch

Name                        Type  Local Value            Peer Value             
-------------               ----  ---------------------- -----------------------
Nve1 Vni, Mcast, Mode,      1     100010, 0.0.0.0,       100010, 0.0.0.0,      
Type, Flags                       Mcast, L2, None        UcastBGP, L2, None    
Nve1 Vni, Mcast, Mode,      1     100020, 0.0.0.0,       100020, 0.0.0.0,      
Type, Flags                       Mcast, L2, None        UcastBGP, L2, None    
Nve1 Vni, Mcast, Mode,      1     100030, 0.0.0.0,       100030, 0.0.0.0,      
Type, Flags                       Mcast, L2, None        UcastBGP, L2, None  

N9K-1# show running-config interface nve1
<snip>
!Command: show running-config interface nve1
!Running configuration last done at: Tue May 12 12:37:42 2020
!Time: Tue May 12 13:30:39 2020

version 9.3(1) Bios:version 07.66 

interface nve1
  no shutdown
  host-reachability protocol bgp
  source-interface loopback0
  member vni 100010
    ingress-replication protocol bgp
  member vni 100020
    ingress-replication protocol bgp
  member vni 100030
    ingress-replication protocol bgp

Conditions:
1. Two Nexus 9000 devices in a vPC domain
2. Devices configured for VXLAN BGP EVPN fabric
3. One vPC peer is reloaded
4. When the reloaded device comes back online, some vPC VLANs are suspended due to Type 1 Compatibility Check failure.

A supported ISSU upgrade from a previous NX-OS software release is required to invoke this issue.
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