Re: Core knowledge Q from Anthony J. Sequeira - Diagrams for

Hey Andrew!

Cisco announced the Troubleshooting section would indeed be on a
separate pod from the Config portion, so we need to be ready for
unique layouts there and IP addressing.

Much like the Config portion, I think it is safe to assume a wide
variety of diagrams to be presented in this section based on the
tasks. And these diagrams will vary from lab to lab in order to help
protect the integrity of the exam.

For this specific troubleshooting task you mentioned, immediately when
I see a tunnel involved with multicast, I would immediately check RPF
failure. This is a real common gotcha with the use of tunnels and
Multicast. I love to use "show ip route source_prefix" to determine
what the unicast routing table believes for pathing, then check the
multicast path.

I would believe the lab document here when they indicate that
multicast is broken and apply a fix. After the application of a fix, I
would move toward the use of ping and mtrace.

Warmest Regards,

Anthony J. Sequeira, CCIE #15626
http://www.INE.com

Test your Core Knowledge today!
Q: What Layer 3 redundancy protocol is shown in the Exhibit below?
(Exhibit shows topology that includes AVG and AVF devices.)
A: Gateway Load Balancing Protocol
More Info: http://www.cisco.com/en/US/docs/ios/12_2t/12_2t15/feature/guide/ft_glbp.html#wp1039649

On Sep 25, 2009, at 1:35 PM, ALL From_NJ wrote:

> Hello Team, happy Friday.
>
> Was thinking about the tshooting section and I saw an old post from
> Anthony
> which included this Q&A:
>
> Q: If you create a tunnel for multicast traffic and do not enable an
> IGP over the tunnel, what command is needed on the router that needs
> to receive the multicast feeds?
> A: ip mroute
>
> I was like wow ... ok, cool. This would not have crossed my mind in
> the
> past and I got to thinking about how a tshooting ticket might look.
>
> Question for the team -
>
> 1) How would you have gone about tshooting this? Start w/ a ping or
> mtrace?
> 2) How to discover these things quickly?
> 3) Does it help to see that the routers register the s,g correctly,
> but that
> a ping fails?
>
> My guess is that a question like this would state something like
> "administrator bob has configured his network for mcast, however
> when bob
> starts a mcast stream, traffic does not go through. Fix bob's
> network".
>
> Also - will we have a separate set of diagrams and addressing for the
> tshooting section?
>
> Rock on team, and many TIA,
>
> --
> Andrew Lee Lissitz
> all.from.nj_at_gmail.com
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Fri Sep 25 2009 - 14:38:31 ART