From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Wed Aug 18 2004 - 21:54:56 GMT-3
Richard,
I would suggest to ask the proctor. Usually if there is a requirement they will tell you, i.e. IP reachability, route a certain way, etc. Making you assume that something should be configured gives the test a design aspect, which in reality it doesn't have.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
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________________________________________
From: Richard Dumoulin [mailto:richard.dumoulin@vanco.es]
Sent: Wednesday, August 18, 2004 6:09 PM
To: Brian McGahan; lab
Subject: RE: multicast basic question
Oh btw, if in a scenario it is said "configure pim etc ..." and there is no requirement of multicast connectivity but you know a GRE tunnel is needed to connect the frame-relay spokes, should the tunnel be configured or not ?
So should there be connectivity between all the routers in the multicast domain ? Or should we expect this to be an explicit requirement ?
Thanks
--Richard
-----Original Message-----
From: Brian McGahan [mailto:bmcgahan@internetworkexpert.com]
Sent: jueves, 19 de agosto de 2004 0:49
To: John Matus; lab
Subject: RE: multicast basic question
John,
Anytime to send traffic with a multicast destination, you are generating a "feed". The router can generate this with features such as ping, traceroute, or SAA. The reason the S,G entry shows up in R2's routing table is because it received a "feed" from 150.1.1.1 going to the group 255.5.5.5. If R1 receives an ICMP echo-reply from R2, then the end to end path is good. If R1 doesn't receive the reply, the majority of the time it is due to RPF failure.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
Live Chat: http://www.internetworkexpert.com/chat/
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> John Matus
> Sent: Wednesday, August 18, 2004 3:51 PM
> To: lab
> Subject: multicast basic question
>
> ok, here goes...
> in a lab scenario, one where there is no real multicast feed to play
> with.... say the lab asks you to configure pim on routers 1, 2 and 3
> and also
asks
> that
> routers 1, 2, and 3 join multicast group 225.5.5.5. and then asks
that
> router
> 1 be able to get ping responses from 2 and 3....
>
> when you join an interface to a multicast group ( ip igmp join-group
> 225.5.5.5), i've noticed that it will show up in the other router's
mroute
> tables as (150.1.1.1, 255.5.5.5) (from r2's perspective). my
question
> is
> does that somehow create a 'source' of multicast traffic since it
shows up
> in
> the mroute table? some of the labs i've seen will ask you to
configure
> multicast and then tell you that you can use static mroutes, but i
don't
> see
> how it is possible to test for RPF is there is no real multicast
source.
> so
> i'm confused about 1) what a multicast source is in these lab
scenarios
> and 2)
> how do you test for RPF without a 'source'
>
> also, if i join routers 1, 2, and 3 to multicast group 225.5.5.5,
should
> they
> all respond to pings to that group....and if they don't, am i supposed
to
> use
> static mroutes to get to each other? (this is all just hypothetical of
> course)
>
> thanks in advance!
>
>
>
> John D. Matus
> MCSE, CCNP
> Office: 818-782-2061
> Cell: 818-430-8372
> jmatus@pacbell.net
>
>
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