C3850-48XS-E - SSO - redundancy force-switchover - causes OSPF interruption

geburtige · ‎05-06-2019

Hello everyone,

i have a problem with a pair of 3850-48XS-E (stacked with stackwise-virtual).

IOS-XE Version 16.6.5.

The 3850 is used as a distributions switch with two L3 connection (each with two 40GB interfaces in LACP channel) to the backbone (backbone - two Nexus 7700).

When I perform a redundancy force-switchover at the distributionsswitch, all L3 connections to the backbone are aborted and I have an interrupt in the network for more than 10 seconds.

The OSPF config on 3850:

router ospf XX
 router-id X.X.X.X
 log-adjacency-changes detail
 auto-cost reference-bandwidth 40000
 nsr
 nsf
 timers throttle spf 10 100 5000
 timers throttle lsa 0 100 5000
 timers lsa arrival 80
 redistribute static subnets
 passive-interface default
 no passive-interface Port-channel1
 no passive-interface Port-channel2
 network 10.0.0.0 0.255.255.255 area 0
 default-information originate
!

Interface config 3850:

interface Port-channel1
 no switchport
 ip address X.X.X.X
 ip pim sparse-mode
 ip ospf authentication
 ip ospf authentication-key 7 XXX
 ip ospf network point-to-point
 ip ospf dead-interval 2
 ip ospf hello-interval 1
 carrier-delay msec 0

The OSPF config on Nexus 7700:

router ospf XX
  bfd
  router-id X.X.X.X
  rfc1583compatibility
  default-information originate route-map ALL
  redistribute direct route-map ALL
  redistribute static route-map ALL
  area 0.0.0.0 range 10.0.0.0/8
  log-adjacency-changes detail
  name-lookup
  timers throttle spf 10 100 5000
  timers lsa-arrival 100
  timers throttle lsa 0 100 5000
  maximum-paths 4

Interface config Nexus:

interface port-channel1
  ip address X.X.X.X/30
  ip ospf authentication
  ip ospf authentication-key 3 XXX
  ip ospf dead-interval 2
  ip ospf hello-interval 1
  ip ospf network point-to-point
  no ip ospf passive-interface
  ip router ospf 10 area 0.0.0.0
  ip pim sparse-mode

I think i have only a configuration error and hope that you can help me find a solution.

Let me know, if u need some more information.

Thanks and regards

Enrico

Sebastian Fernandez · ‎05-06-2019

Hi @geburtige

To support NSF make sure there is an IP Service license and also the OSPF neighbor needs to be nsf aware.

From CCO

The switch supports NSF-awareness and NSF-capability for the BGP, OSPF, and EIGRP protocols in IP Services license level and NSF-awareness for the EIGRP-stub in IP Base license level.

Also you may find other useful information at

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3850/software/release/3se/ha_stack_manager/configuration_guide/b_hastck_3se_3850_cg/b_hastck_3se_3850_cg_chapter_011.html

***** Please mark this post as helpful if it contributes to your solution ******

-

Sebastian