[Xorp-users] Upstream MRIB nexthop (RP) UNKNOWN

Pavlin Radoslavov pavlin@icir.org
Fri, 23 Jul 2004 17:26:11 -0700


Husni,

Yes, line 3 appears bogus, but accidentally that doesn't matter,
because RPF'(*,G) is correct. All other UNKNOWN MRIB entries for
the RP follow from that bogus entry. Note that lines 25 and 26 are
OK, because they refer to a directly-connected source, and by
definition there is no next-hop router toward such sources.

Though, I wonder if "Upstream MRIB next hop (RP)" is UNKNOWN, how
"Upstream RPF'(*,G)" was assigned value of 10.1.1.1.
The only reason that comes to mind is if there was an exchange of
Assert messages on interface fxp1. Could you verify that by checking
the log messages and by checking the assert-related "show pim join"
state (e.g., "Assert Lost WC" for the (*,G) entry should be set to
"O" for fxp1).

I have a suspicion about the source of the problem. To verify my
suspicion, could you run the stand-alone pim/test_pim instead and
check whether you still get that bogus UNKNOWN entry. If you are not
familiar with how to configure and run it, please read pim/README.

Thanks,
Pavlin


> Dear All,
> 
> I use XORP for PIM-SM only. On my FreeBSD, the MRIB entries are coming
> from the kernel routing table as below.
> 
> DestPrefix         NextHopRouter   VifName VifIndex MetricPref Metric
> 10.1.1.0/24        10.1.1.100      fxp1    1                 0      0
> 10.10.1.0/24       10.1.1.1        fxp1    1               254  65535
> 10.20.1.0/24       10.20.1.1       fxp0    0                 0      0
> 
> I am wondering why the Upstream MRIB next hop (RP) is always UNKNOWN?
> 
> Below is the (truncated) results of show pim join. (I typed the line numbers)
> 
> Thank you,
> -husni-
> 
>    Group           Source          RP              Flags
>  1 239.18.100.100  0.0.0.0         10.10.1.1       WC
>  2     Upstream interface (RP):   fxp1
>  3     Upstream MRIB next hop (RP): UNKNOWN
>  4     Upstream RPF'(*,G):        10.1.1.1
>  5     Upstream state:            Joined
>  6     Join timer:                41
> 
> ...
> 
>    Group           Source          RP              Flags
>  7 239.18.100.100  10.20.1.20      10.10.1.1       SG_RPT DirectlyConnectedS
>  8     Upstream interface (S):    fxp0
>  9     Upstream interface (RP):   fxp1
> 10     Upstream MRIB next hop (RP): UNKNOWN
> 11     Upstream RPF'(S,G,rpt):    10.1.1.1
> 12     Upstream state:            Pruned
> 
> ...
> 
>    Group           Source          RP              Flags
> 13 239.18.100.100  10.10.1.10      10.10.1.1       SG SPT
> 14     Upstream interface (S):    fxp1
> 15     Upstream interface (RP):   fxp1
> 16     Upstream MRIB next hop (RP): UNKNOWN
> 17     Upstream MRIB next hop (S):  10.1.1.1
> 18     Upstream RPF'(S,G):        10.1.1.1
> 19     Upstream state:            Joined
> 20     Join timer:                56
> 
> ...
> 
>    Group           Source          RP              Flags
> 21 239.18.100.100  10.20.1.20      10.10.1.1       SG SPT DirectlyConnectedS
> 22     Upstream interface (S):    fxp0
> 23     Upstream interface (RP):   fxp1
> 24     Upstream MRIB next hop (RP): UNKNOWN
> 25     Upstream MRIB next hop (S):  UNKNOWN
> 26     Upstream RPF'(S,G):        UNKNOWN
> 27     Upstream state:            Joined
> 28     Register state:            RegisterPrune RegisterCouldRegister
> 29     Join timer:                38
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