[j-nsp] nssa default route

ryanL ryan.landry at gmail.com
Thu Aug 16 13:47:31 EDT 2012


tl;dr - when i kill one of my mx's, the default route disappears on my
ex's. and, the remaining ospf database entry is for the router that
died, not the router that remains active.

i might be a little slow on the uptick here, but this seems pretty
straight forward to me. i can't figure out what's up. i'm pretty new
to junos, so bear with me.

m = mx
e = ex
standard physical full mesh

mx1 lo0 = 1.1.1.1
mx2 lo0 = 1.1.1.2

m - m
| x |
e - e

my mx are ospf area 0 and area 1 nssa. the ex are area 1 nssa only.
mx's inject default into nssa.

config on mx:

//
area 0.0.0.0 {
    interface lo0.0 {
        passive;
    }
    interface ae0.0 {
        interface-type p2p;
        bfd-liveness-detection {
            minimum-interval 300;
            multiplier 3;
            full-neighbors-only;
        }
    }
}
area 0.0.0.1 {
    nssa {
        default-lsa default-metric 10;
        no-summaries;
    }
    interface ae1.0 {
        interface-type p2p;
        bfd-liveness-detection {
            minimum-interval 300;
            multiplier 3;
            full-neighbors-only;
        }
    }
    interface ae2.0 {
        interface-type p2p;
        bfd-liveness-detection {
            minimum-interval 300;
            multiplier 3;
            full-neighbors-only;
        }
    }
}
//

config on ex:

//
area 0.0.0.1 {
    nssa;
    interface lo0.0 {
        passive;
    }
    interface ae1.0 {
        interface-type p2p;
        bfd-liveness-detection {
            minimum-interval 300;
            multiplier 3;
            full-neighbors-only;
        }
    }
    interface ae2.0 {
        interface-type p2p;
        bfd-liveness-detection {
            minimum-interval 300;
            multiplier 3;
            full-neighbors-only;
        }
    }
    interface ae0.0 {
        interface-type p2p;
        bfd-liveness-detection {
            minimum-interval 300;
            multiplier 3;
            full-neighbors-only;
        }
    }
}
//

routes before killing mx2:
>show route 0.0.0.0

inet.0: 28 destinations, 28 routes (28 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

0.0.0.0/0          *[OSPF/10] 00:08:40, metric 15
                    > to 10.254.1.2 via ae1.0
                      to 10.254.1.4 via ae2.0

ospf database before killing mx2:
> show ospf database

    OSPF database, Area 0.0.0.1
 Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
Router  *10.255.1.1       10.255.1.1       0x8000048e  2283  0x20 0x7c36 168
Router   10.255.1.2       10.255.1.2       0x80000486  2284  0x20 0x1e89 168
Router   1.1.1.1     1.1.1.2     0x800003e2   513  0x20 0x7006  72
Router   1.1.1.2     1.1.1.2     0x800003e8  1082  0x20 0x7bf2  72
Summary  0.0.0.0          1.1.1.1     0x80000001   513  0x20 0xeaa8  28
Summary  0.0.0.0          1.1.1.2     0x800000b4  1082  0x20 0x7d61  28



routes after killing mx2:
> show route 0.0.0.0
#<----nothing here
{master:0}

ex ospf database after killing mx2:
> show ospf database

    OSPF database, Area 0.0.0.1
 Type       ID               Adv Rtr           Seq      Age  Opt  Cksum  Len
Router  *10.255.1.1       10.255.1.1       0x80000490    41  0x20 0x286f 144
Router   10.255.1.2       10.255.1.2       0x80000488    42  0x20 0x6030 144
Router   1.1.1.1     1.1.1.2     0x800003e2   612  0x20 0x7006  72
Router   1.1.1.2     1.1.1.2     0x800003e8  1181  0x20 0x7bf2  72
Summary  0.0.0.0          1.1.1.2     0x800000b4  1181  0x20 0x7d61
28  #<---dead router!

so, what happened to my remaining router's ospf database entry, and
that secondary default route?

thanks for any insight. i'm going to open a case with jtac as well.

ryanL


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