CCIE Pursuit Blog

December 2, 2007

Internetwork Expert Volume II: Lab 2 – Section 6

Section 6 – IP Multicast – 6 Points

Multicast is my absolute worst technology.  I had very little hope of getting any of these tasks correct because I really haven’t done a lot of multicast study.  This section turned out to be a pleasant surprise as the first two tasks were very easy. 

6.1 asks you to configure a number of interfaces in pim sparse-mode.  The task is  very straight-forward.  You are then asked to:

Configure r2’s most reliable interface as the RP for all multicast groups.

The most reliable interface must be lo0.  Two things to keep in mind: 1) if you make an interface the RP, you’d better configure it for multicast (pim sparse-mode in this case) even if the task does not explicitly list it (as it did not in this case), and 2) you need to configure the RP address on each device (“ip pim rp-address x.x.x.x”).

6.2 just requires you to use “ip igmp join-group”.

6.3 completely bewildered me.  The task described what would seem to be a complicated issue but it was resolved with “ip pim nbma-mode”.  Oh well, I’m pretty happy with getting the first two sections correct.

1 Comment »

  1. Here’s a link regarding the ip pim nbma-mode command, and some of the limitations of Auto-RP over Frame Relay. If the task had asked for r2 to be the rp, and say r3 to be a backup rp, use BSR.

    Comment by Brian — December 3, 2007 @ 3:32 pm | Reply

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