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BFD not working on vMX

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  • 1.  BFD not working on vMX

     
    Posted 05-27-2018 04:26

    I am trying to get BFD to work on vMX. It's configured exactly how it would be in our production network, but for some reason, there are no BFD packets leaving the local vMX. I have a vMX interface attached to a vSRX and I can see the vSRX sending BFD, but the vMX is not sending anything back. I've tried it on several vMX installs and it's all the same behavior. Is there something I am missing in getting this working?

     

    I'm on 18.1 in the vMX, running a PREMIUM license. There are no firewall filters applied to the RE.

     

    group as65222 {
        local-address 192.168.50.33;
        peer-as 65222;
        bfd-liveness-detection {
            minimum-interval 1000;
            multiplier 3;
            session-mode single-hop;
        }

    Output from show bfd session:

    admin@vmx1> show bfd session extensive 
                                                      Detect   Transmit
    Address                  State     Interface      Time     Interval  Multiplier
    192.168.50.34             Init      xe-0/0/3.0     6.000     2.000        3   
     Client BGP, TX interval 1.000, RX interval 1.000
     Local diagnostic None, remote diagnostic None
     Remote state Down, version 1
     Session type: Single hop BFD
     Min async interval 1.000, min slow interval 2.000
     Adaptive async TX interval 2.000, RX interval 2.000
     Local min TX interval 2.000, minimum RX interval 1.000, multiplier 3
     Remote min TX interval 2.000, min RX interval 2.000, multiplier 3
     Local discriminator 17, remote discriminator 16
     Echo mode disabled/inactive, no-absorb, no-refresh
      Session ID: 0x140
    
    1 sessions, 1 clients
    Cumulative transmit rate 0.5 pps, cumulative receive rate 0.5 pps

    Output from monitor traffic:

    admin@vmx1> monitor traffic interface xe-0/0/3.0 no-resolve size 1500 matching "udp port 3784" 
    verbose output suppressed, use <detail> or <extensive> for full protocol decode
    Address resolution is OFF.
    Listening on xe-0/0/3.0, capture size 1500 bytes
    
    10:46:53.858927 In IP 192.168.50.34.49152 > 192.168.50.33.3784: BFDv1, One-hop Control, State Down, Flags: [none], length: 24
    10:47:06.736092 In IP 192.168.50.34.49152 > 192.168.50.33.3784: BFDv1, One-hop Control, State Down, Flags: [none], length: 24
    10:47:18.930322 In IP 192.168.50.34.49152 > 192.168.50.33.3784: BFDv1, One-hop Control, State Down, Flags: [none], length: 24

    bfd traceoptions output:

    May 27 10:51:54 [THROTTLE]bfdd_rate_limit_program_timer_expiry: Session 192.168.50.34 is moved state = 2 Time Elapsed since last packet = 02:30:01
    May 27 10:51:54 [THROTTLE]bfdd_rate_limit_program_timer_expiry: Session 192.168.50.34 is removed form program therad
    May 27 10:51:54 bfdd_rate_limit_program_timer_expiry: Slow start revert
    May 27 10:51:54 [RE_PPS]bfdd_slow_start_revert_poll_batch: RE PPS was 0 max_pps 5000 orginal_max_pps 5000 pend_pps 0 outstnading_poll 0
     
    May 27 10:51:54 [SLOW_START]bfdd_slow_start_revert_poll_batch: processed 0 sessions
    May 27 10:51:54 [SLOW_START]bfdd_slow_start_timer_expiry: Slow start thread not empty, calling slow start reversal
    May 27 10:51:57 Received Downstream RcvPkt (19) len 102:
    May 27 10:51:57    IfIndex (3) len 4: 332
    May 27 10:51:57    Protocol (1) len 1: BFD
    May 27 10:51:57    SrcAddr (5) len 8: 192.168.50.34
    May 27 10:51:57    Data (9) len 24: (hex) 20 40 03 18 00 00 00 10 00 00 00 00 00 1e 84 80 00 1e 84
    May 27 10:51:57    PktError (26) len 4: 0
    May 27 10:51:57    RtblIdx (24) len 4: 0
    May 27 10:51:57    MultiHop (64) len 1: (hex) 00
    May 27 10:51:57    Seamless (245) len 1: 0
    May 27 10:51:57    Unknown (213) len 1: (hex) 00
    May 27 10:51:57    Unknown (168) len 1: (hex) 00
    May 27 10:51:57    Authenticated (121) len 1: (hex) 00
    May 27 10:51:57 BFD packet from 192.168.50.34 (IFL 332), len 24
    May 27 10:51:57    Ver 1, diag 0, mult 3, len 24
    May 27 10:51:57    Flags: ,  State: Down
    May 27 10:51:57    My discr 0x00000010, your discr 0x00000000
    May 27 10:51:57    Tx ivl 2000000, rx ivl 2000000, echo rx ivl 0
    May 27 10:51:57 [THROTTLE]bfdd_rate_limit_can_accept_pkt: session 192.168.50.34 pkt rcvd for a session which might be deleted or down so adding that session to program/pending thread
    May 27 10:51:57 [SLOW_START]bfdd_slow_start_start: 192.168.50.34 is already in slow start thread
    May 27 10:51:57 [THROTTLE] bfdd_rate_limit_start_program_timer: Starting program timer
    May 27 10:51:57 [THROTTLE]bfdd_rate_limit_add_ppm_thread:Session 192.168.50.34 added to program thread
    May 27 10:51:57 [THROTTLE]bfdd_rate_limit_can_accept_pkt: session 192.168.50.34 moved from pending to program
    May 27 10:51:57 (bfdd_update_tx_intervals:510) Session 192.168.50.34 (IFL 332): cur tx ivl 2000000, new_invl 0(2,0,2000000,2000000)
     
    May 27 10:51:57 (bfdd_update_tx_intervals:537) Session 192.168.50.34 (IFL 332): cur tx ivl 2000000, new_invl 2000000
     
    May 27 10:51:57 (bfdd_update_tx_intervals:555) Session 192.168.50.34 (IFL 332): cur tx ivl 2000000, new_invl 2000000

     



  • 2.  RE: BFD not working on vMX

    Posted 05-28-2018 11:35

    How are you running vMX? vmware? kvm (and what OS)?

     

    What physical NICs are you using? X520? X710? etc.



  • 3.  RE: BFD not working on vMX

     
    Posted 05-29-2018 02:25

    I'm running on VMware 5.5 and I am not sure of what the physical NICs are. Does the physical NIC matter? If so, is there at least some mention of this in the documentation?



  • 4.  RE: BFD not working on vMX

     
    Posted 05-29-2018 04:49

    I should also mention that it doesn't work in a KVM environment, either.



  • 5.  RE: BFD not working on vMX

    Posted 05-29-2018 04:58

    It can matter, it shouldn't, but it can due to bugs. We've seen no end of issues with Intel X710 NICs (I'd assume XL710 are the same, given the same i40e driver).  The most recent issue we've seen as with OSPF - One side would send and receive Hello packets, the other side the host node would receive Hello, but vMX never received the Hello, only sent them out; so one side was stuck at init because it could see the incoming Hello, the other didn't have a clue.



  • 6.  RE: BFD not working on vMX
    Best Answer

    Posted 05-29-2018 06:00

    Hello,

    Have You tried on VMX:

    set routing-options ppm no-delegate-processing

    HTH

    Thx

    Alex



  • 7.  RE: BFD not working on vMX

     
    Posted 05-29-2018 06:10

    Thanks, Alex! That worked. I'll check out documentation to get more details about that command. Much appreciated.