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BFD over RSVP LSP isn't coming up

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  • 1.  BFD over RSVP LSP isn't coming up

    Posted 04-01-2020 13:20

    Hello everybody,

     

    I hope you are safe wherever you are.

     

    I am configuring BFD over rsvp-based LSP but it is not coming up, I have spent a lot of time checking, can anybody spot where the problem is?

     

    Here is the configuration:

     

     

    pe1:
    
    path te_tunnel_path1 {
        172.17.30.129;
        172.17.50.201;
        17.39.53.50;
        172.17.50.237;
    label-switched-path te_tunnel {
        no-install-to-address;
        to 17.39.53.20;
        install 172.28.173.35/32;
        primary te_tunnel_path1 {
            oam {
                bfd-liveness-detection {
                    minimum-interval 100;
                    minimum-receive-interval 120;
                    multiplier 3;
                    failure-action teardown;
                }
            }
        }
        secondary te_tunnel_path2 {
            standby;
    
    
    pe2:
    
    label-switched-path te_tunnel_path1 {
        no-install-to-address;
        to 17.39.53.5;
        install 172.28.173.220/32;
        primary te_tunnel_path1;
        secondary te_tunnel_path2 {
            standby;
        }
    }
    path te_tunnel_path1 {
        172.17.50.238;
        172.17.51.109;
        172.17.50.202;
        172.17.30.130;
    }
    path te_tunnel_path2 {
        17.39.53.5 loose;
    }
    

     

    BFD sessions status at both sides:

     

                                                      Detect   Transmit
    Address                  State     Interface      Time     Interval  Multiplier
    127.0.0.1                Down      ge-0/1/0.1   0.000     1.000        0
     Client RSVP-OAM, TX interval 0.000, RX interval 0.000
     Local diagnostic None, remote diagnostic None
     Remote not heard, doesn't hear us, version 0
     Replicated 
     Min async interval 0.000, min slow interval 1.000
     Adaptive async TX interval 0.000, RX interval 0.000
     Local min TX interval 1.000, minimum RX interval 0.000, multiplier 0
     Remote min TX interval 0.000, min RX interval 0.000, multiplier 0
     Local discriminator 114, remote discriminator 0
     Echo mode disabled/inactive, no-absorb, no-refresh, update-adj
     LSP-Name te_tunnel1
     Path-Name te_tunnel_path1
                                                      Detect   Transmit
    Address                  State     Interface      Time     Interval  Multiplier
    127.0.0.1                Down      ge-1/1/0.1   0.000     1.000        3
     Client RSVP-OAM, TX interval 0.100, RX interval 0.120
     Local diagnostic None, remote diagnostic None
     Remote state AdminDown, version 1
     Replicated 
     Min async interval 0.100, min slow interval 1.000
     Adaptive async TX interval 0.100, RX interval 0.120
     Local min TX interval 1.000, minimum RX interval 0.120, multiplier 3
     Remote min TX interval 0.000, min RX interval 0.000, multiplier 0
     Local discriminator 13, remote discriminator 0
     Echo mode disabled/inactive, no-absorb, no-refresh, update-adj
     LSP-Name te_tunnel1
     Path-Name te_tunnel_path1
    

     


    #BFD
    #rsvp
    #MPLS


  • 2.  RE: BFD over RSVP LSP isn't coming up

    Posted 04-01-2020 21:06

    Hello,

     

    Have You allowed UDP port 3784 in Your loopback filter?

    https://tools.ietf.org/html/rfc5884#section-7

     

    HTH

    Thx

    Alex



  • 3.  RE: BFD over RSVP LSP isn't coming up

    Posted 04-01-2020 22:31
    Yes Alex, I did


  • 4.  RE: BFD over RSVP LSP isn't coming up

    Posted 04-01-2020 22:54

    Hello,

     

    Ok, in this case You might need to assign 127.0.0.1/32 to Your lo0.0, please try it.

    Some JUNOS versions do not require it but some do.

    Alternatively, You can use "receive" route:

     

    set routing-options static route 127.0.0.1/32 receive

     

    HTH

    Thx

    Alex

     



  • 5.  RE: BFD over RSVP LSP isn't coming up

    Posted 04-02-2020 00:25

    Thank you Alex, I did both -secondary IP address on lo0.0 and receive route- and none of them is working, I can't even see BFD packets coming out of the interface when I do "monitor traffic", however the log shows the bfd session bouncing, going up and down in the same second:

    Apr  2 09:39:16  pe1 bfdd[1362]: BFD Session 127.0.0.1 (IFL 348) state Up -> Down LD/RD(218/217) Up time:00:00:03 Local diag: AdminDown Remote diag: None Reason: Received Upstream Destroy Session.
    Apr  2 09:39:16  pe1 bfdd[1362]: BFDD_TRAP_STATE_DOWN: local discriminator: 218, new state: down
    

     

    I feel that it's simple, something is blocking the BFD local on the router, any more ideas?

     

    BR,

     

    MP



  • 6.  RE: BFD over RSVP LSP isn't coming up

    Posted 04-02-2020 00:58

    Worth mentioning that one of the two router is an m10i runninig JUNOS 10.3R1.9, I though that this might be legacy so it deserve an upgrade, any recommndations?

     



  • 7.  RE: BFD over RSVP LSP isn't coming up
    Best Answer

    Posted 04-02-2020 03:03

    If finally worked after allowing the LSP ping port number 3503, quoting from RFC 5884 "BFD for MPLS label switched paths": 

       If there are multiple alternate paths from an ingress LSR to an
       egress LSR for an LDP IP FEC, LSP Ping traceroute MAY be used to
       determine each of these alternate paths.  A BFD session SHOULD be
       established for each alternate path that is discovered.
    
       Periodic LSP Ping Echo request messages SHOULD be sent by the ingress
       LSR to the egress LSR along the same data path as the LSP.  This is
       to periodically verify the control plane against the data plane by
       ensuring that the LSP is mapped to the same FEC, at the egress, as
       the ingress.  The rate of generation of these LSP Ping Echo request
       messages SHOULD be significantly less than the rate of generation of
       the BFD Control packets.  An implementation MAY provide configuration
       options to control the rate of generation of the periodic LSP Ping
       Echo request messages.
    

    this document shows the LSP ping port number that was allowed on the loopback filter: https://www.juniper.net/documentation/en_US/junos/topics/usage-guidelines/mpls-pinging-lsps.html

     

    term lsp_ping {
        from {
            protocol udp;
            port 3503;
        }
        then accept;

     

    the session then worked.

    Thanks Alex for your time and help.

    MP