From: Duongla (duongla@vnn.vn)
Date: Sat Sep 03 2005 - 00:58:36 GMT-3
Thanks Marschner for your clear explaination.
Hi dusth@comcast.net, in this scenario, I did use manual RP configuration,
so I did not configure mapping agent anywhere.
Regards
Duongla
----- Original Message -----
From: "Wolfgang Marschner" <wmarschner@web.de>
To: "Duongla" <duongla@vnn.vn>; <ccielab@groupstudy.com>
Sent: Saturday, September 03, 2005 1:17 AM
Subject: Re: Multicast forwarding fails with fast switching but OK with
process.Can U help?
> Hi,
>
> this is a normal behaviour with Multicast over NBMA.
> It works with "pseudobroadcast", that means, by replicating
> the packets on the hub to the spoke VC's, when broadcast is
> enabled per auto-mapping ( inverse-arp ) or manual mapping
> ( frame-relay map IP-address dlci DLCi-number braodcast ).
>
> The hub must pseudobroadcast because of the split horizon rule,
> but that can be only done on layer 2 with process-switching on
> a router.
>
> To override this behavior, configure on the hub interface the
> command "ip pim nbma-mode".
> Now the hub router can replicate the packets on layer 3
> with fast-switching.
>
> When you take a look in the Multicast routing table you will
> notice, that every spoke-connection joined for a multicast
> group will appear as a seperate entry in the
> Outgoing Interface List ( OIL ).
> For that reason, no more problems will noticed, when a spoke
> router leaves a multicast-group while working in PIM DM.
>
> Hope that helps.
>
> W. Marschner
> CCIE #8232
>
>
> ----- Original Message -----
> From: "Duongla" <duongla@vnn.vn>
> To: <ccielab@groupstudy.com>
> Sent: Friday, September 02, 2005 7:15 PM
> Subject: Multicast forwarding fails with fast switching but OK with
> process.Can U help?
>
>
> > Hi group,
> >
> > I have tried the following scenario on 4 Cisco 2600:
> > R1,R2 and R3 are connected via multipoint frame-relay (physical
> > interface), R2
> > is the HUB.
> > Routing is running normally, all routers can reach all subnets.
> > R2 f0/0 connect to R4 whichs is a test router, responsible for
genarating
> > multcast traffic.
> > R1,R2,R3 are all configured with multicast PIM sparse mode and loopback
> > interface of R3
> > is configured manually on 3 routers as RP.
> > R1f0/0 and R3 f0/0 are configured to join group 239.1.1.1
> > Before PING 239.1.1.1 from R4, the mroute tables int 3 router are in
> > normal
> > state:
> > R1,R3 send Join msg to RP which is R2, so R2 has a (*,239.1.1.1) entry
in
> > its
> > mroute table.
> > For first PING 239.1.1.1 from R4, both R1 and R3 reply.
> > From second PING, just R3 replies.
> > Do debug ip mpacket fastswitch 239.1.1.1, I saw R2 forwarded the mcast
> > packet
> > from R4 out serial0/0
> > (the frame relay port, connecting to R1 and R3) but just R3 got the
packet
> > and
> > sent PING echo-reply.
> > One interesting notice is: router with higher IP address of frame relay
> > interface receives the PING mcast packet.
> > In this case R3.
> > If I turn off fast switching on R2 s0/0 then both R1 and R3 receive
mcast
> > packet.
> >
> > Can anyone help clarify the above behaviour ?
> > Thanks in advance.
> > Duongla
> >
> > _______________________________________________________________________
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