[j-nsp] BFD timers for OSPF - MX80 - 10.3R2.11

[David Ball]

MX80s running 10.3R2.11

  For those of you using BFD for OSPF, how low have you been able to
set your minimum-interval timer?  I have a pair of MX80s connected via
XFPs and 1m patch cables and with my hellos set to 30ms and multiplier
set to 3, I'm seeing failures.  I haven't disabled distributed ppm.
Moving to 50ms hellos seems to settle things down.  The reason I'm
wondering why I can't get away with lower timers is because when
Juniper proof-of-concepted (yeah, that's a verb) Trio for us (albeit
using MX960s), they used 15ms hellos with a multiplier of 3.

Mar  3 10:06:06  router bfdd[1129]: BFDD_TRAP_STATE_DOWN: local
discriminator: 1, new state: down
Mar  3 10:06:06  router rpd[1257]: RPD_OSPF_NBRDOWN: OSPF neighbor
172.16.1.22 (realm ospf-v2 xe-0/0/2.0 area 0.0.0.0) state changed from
Full to Down due to InActiveTimer (event reason: BFD session timed out
and neighbor was declared dead)


me at router> show configuration groups bfd-defaults-core-ospf
protocols {
    ospf {
        area 0.0.0.0 {
            interface <*> {
                bfd-liveness-detection {
                    version automatic;
                    minimum-interval 30;
                    multiplier 3;
                    full-neighbors-only;
                }
            }
        }
    }
}

me at router> show configuration protocols ospf area 0.0.0.0
interface lo0.0 {
    passive;
}
interface xe-0/0/2.0 {
    apply-groups bfd-defaults-core-ospf;
    node-link-protection;
}
interface xe-0/0/3.0 {
    apply-groups bfd-defaults-core-ospf;
    node-link-protection;
}


David