NX-OSv problems with basic BFD

[dukenuk96]

Hi all!

I am testing N9k in virtual environment:

NX-OSv9K is a demo version of the Nexus Operating System

Software
  BIOS: version 
  NXOS: version 7.0(3)I5(2)
  BIOS compile time:  
  NXOS image file is: bootflash:///nxos.7.0.3.I5.2.bin
  NXOS compile time:  2/16/2017 8:00:00 [02/16/2017 17:03:27]


Hardware
  cisco NX-OSv Chassis 
   with 8160556 kB of memory.
  Processor Board ID 9DOV2BAZYKE

  Device name: NX2
  bootflash:    3509454 kB
Kernel uptime is 0 day(s), 5 hour(s), 18 minute(s), 9 second(s)

And try to establish BFD session:

interface Vlan99
  bfd interval 500 min_rx 500 multiplier 3
  no bfd echo
  bfd authentication Keyed-SHA1 key-id 1 hex-key 123
  bfd ipv4 interval 500 min_rx 500 multiplier 3
  ip ospf bfd
router ospf 1
  bfd

But session does not come up due to lack of resources:

NX2# sh bfd neighbors det

OurAddr         NeighAddr       LD/RD                 RH/RS           Holdown(mu
lt)     State       Int                   Vrf                             
11.11.11.1      11.11.11.2      1090519041/0          Down            N/A(3)    
        Down        Vlan99                default                         

Session state is Down and not using echo function
Local Diag: 0, Demand mode: 0, Poll bit: 0, Authentication: Keyed-SHA1
MinTxInt: 0 us, MinRxInt: 0 us, Multiplier: 0
Received MinRxInt: 0 us, Received Multiplier: 0
Holdown (hits): 0 ms (0), Hello (hits): 0 ms (0)
Rx Count: 0, Rx Interval (ms) min/max/avg: 0/0/0 last: 0 ms ago
Tx Count: 0, Tx Interval (ms) min/max/avg: 0/0/0 last: 0 ms ago
Registered protocols:  ospf
Downtime: 0 days 0 hrs 17 mins 19 secs
Last packet: Version: 0                - Diagnostic: 0  
             State bit: AdminDown      - Demand bit: 0  
             Poll bit: 0               - Final bit: 0  
             Multiplier: 0             - Length: 24  
             My Discr.: 0              - Your Discr.: 0  
             Min tx interval: 0        - Min rx interval: 0  
             Min Echo interval: 0      - Authentication bit: 0  
Hosting LC: 0, Down reason: No Diagnostic, Reason not-hosted: Req-resp status: n
o resource

NX2# sh logg last 5
2018 Jul  6 14:12:33 NX2 %BFD-5-SESSION_NO_RESOURCES: No resource for session to
 neighbor 11.11.11.2 on interface Vlan99
2018 Jul  6 14:13:19 NX2 last message repeated 1 time
2018 Jul  6 14:14:44 NX2 last message repeated 2 times
2018 Jul  6 14:16:20 NX2 last message repeated 2 times
2018 Jul  6 14:17:34 NX2 last message repeated 2 times

Please help, I do not want to test this on production network.

[mcnairiain]

Hi - I have this exact problem running in EVE Lab.

At first I thought it was a TCAM resource issue with the virtual NXOS image so I re-adjusted the TCAM: taking resouces away from SPAN and aligning the 256 with what I thought BFD would be: - this didn't work.

hardware access-list tcam region SPAN 0

hardware access-list tcam region bfd-multihop 256

Also turned off ip redirects on the L3 interface running bfd - this does nothing either.

What I did notice after carving the TCAM was that the bfd session was no longer admin down - just down - but I suspect its just a limitation with the virtual switch image not supporting bfd echo in virtual hardware.

If you hear of a solution let me know...

[Remi Astruc]

Hello,

The BFD feature is just not supported on Nexus 9000v.

https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/7-x/nx-osv/configuration/guide/b_Cisco_Nexus_9000v/b_Cisco_Nexus_9000v_chapter_011.html#concept_CFB4F9FC4EF04A86835CF9C64C4EB8A4

Remi Astruc

[mcnairiain]

Hi Remi

Thanks for confirming, suspected it might be so...

Cheers.