IPv6 SSM Issue: INE Volumne 1 workbook (v5.019), section 9.28


I'm having an issue with INE Volumne 1 workbook (v5.019), section 9.28.

I cannot get ping working, it is failing for me although the example shows it working on page 1472:
Rack2R6#ping ipv6 FF36::8 re 1000
Output Interface: FastEthernet0/0.146
Type escape sequence to abort.
Sending 1000, 100-byte ICMP Echos to FF36::8, timeout is 2 seconds:
Packet sent with a source address of 2001:1:0:146:223:4FF:FEE5:4278

Request 0 timed out
Request 1 timed out
Request 2 timed out
Request 3 timed out

My best guess is telling me that I am experiencing an RPF failure on R5.  A "show ipv6 mroute" shows a RPF interface of Serial0/0/0:
Rack2R5#sh ipv6 mroute
Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group,
       C - Connected, L - Local, I - Received Source Specific Host Report,
       P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,
       J - Join SPT
Timers: Uptime/Expires
Interface state: Interface, State

(*, FF76:640:2001:CC1E::8), 00:06:28/never, RP 2001:CC1E::6, flags: SCLJ
  Incoming interface: Serial0/0/1
  RPF nbr: FE80::223:4FF:FEE5:4290
  Immediate Outgoing interface list:
    FastEthernet0/0, Forward, 00:06:28/never

(2001:1:0:146:223:4FF:FEE5:4278, FF36::8), 00:06:28/never, flags: sLTI
  Incoming interface: Serial0/0/0
  RPF nbr: FE80::4
  Immediate Outgoing interface list:
    FastEthernet0/0, Forward, 00:06:28/never

However, a "show ipv6 route 2001:1:0:146:223:4FF:FEE5:4278" shows that the outbound interface is Serial0/0/1:
Rack2R5#sh ipv6 route 2001:1:0:146:223:4FF:FEE5:4278
Routing entry for 2001:1:0:146::/64
  Known via "eigrp 100", distance 90, metric 514560, type internal
  Redistributing via rip RIPNG
  Redistributing via ospf 1
  Backup from "rip RIPNG [120]"
  Route count is 2/2, share count 0
  Routing paths:
    FE80::223:4FF:FEE5:4290, Serial0/0/1
      Last updated 00:06:37 ago
    FE80::4, Serial0/0/0
      Last updated 00:06:36 ago

When I shutdown interface Serial0/0/0 on R5, the ping is successful as both the route and the route tables are pointing out the same interface.

With IPv4, I would modify the mroute table with the mroute command but it appears there is not an equivalent command with IPv6.

Any assistance on this one would be appreciated.



  • Hi,

      So you've identified your issue, it's related to routing. Why the SG is functional and you setup is not? For sure your IPv6 routing table is a bit different, have no idea where exactly you did things different. IPV6 static multicast routes are configured with command "ipv6 route .......multicast", so you configure a regular IPV6 static route with "multicast" keyword in the end.

    Good luck with your studies!

  • Hi,

    Thanks for the input.

    Also, how can I identify an RPF issue with IPv6?  I would have expected to see the "RPF failed" counter incrementing in the following output as in IPv4 but it didn't:

    Rack2R5#sh ipv6 mroute FF36::8 count
    IP Multicast Statistics
    60 routes, 12 groups, 0.08 average sources per group
    Forwarding Counts: Pkt Count/Pkts per second/Avg Pkt Size/Kilobits per second
    Other counts: Total/RPF failed/Other drops(OIF-null, rate-limit etc)
    Group: FF36::8
      Source: 2001:1:0:146:223:4FF:FEE5:4278,   Forwarding: 69/0/100/0, Other: 0/0/0
      Tot. shown: Source count: 1, pkt count: 69


    Thanks again!

  • Thanks for the assistance.  This post has helped me identify my issue as well...


    Using ipv6 route 2001:11:0:146:223:4FF:FE97:10E2/128 s0/1/0 multicast on r5 was my fix for this exercise.  This source address will vary for you...

Sign In or Register to comment.