From: Waters, Kivas (UK72) (Kivas.Waters@xxxxxxxxxxxxx)
Date: Sun Jan 13 2002 - 07:43:47 GMT-3
Ravi, I read somewhere that you should put the RP mapping agent on the FR
hub. I'm not sure why this was and it does not make any sense to me but if
you try this and it works, please let me know.
regards
Ki
-----Original Message-----
From: Ravi [mailto:s_ravichandran@hotmail.com]
Sent: 13 January 2002 04:42
To: ccielab@groupstudy.com; bhescock@cisco.com
Subject: Subject: multicast tip and Multicast Sparse-Dense
Hi,
I am doing some multicast labs, finding it very hard to understand. I need
some help please....
I took a example discussed here a month ago (attached below)
I get the same result as what Sijbren Beukenkamp experienced. After spending
hours and hours on the lab and Cisco site, could not get it working. I would
like to bring this topic back and get some solution to this problem.
Regards,
Ravi
Consider the following.
> >
> > Three routers R2, R1 and R4. All interconnected
> using FR. R1 is in the
> > centre and will have to route Multicast between
> its serial interface to
> R2
> > and R4. R2 and R4 have a tokenring interfaces at
> which SD-mode is
> > configured. The same is for all the serial
> interfaces.
> >
> >
>
LAN--------R2-------------FR---------------R1----------FR---------------R4--
-
-----LAN
> >
> > IP MULTICAST-ROUTING IP
> MULTICAST-ROUTING IP
> MULTICAST-ROUTING
> > PIM-S-D
> PIM-S-D PIM-S-D
> > igmp-join 224.1.1.1
> > 224.1.1.1 announced by RP
> > igmp-join 224.2.2.2
> >
> > R2 is RP and mapping agent ONLY for 224.1.1.1. So
> basicly 224.1.1.1 is
> > using Sparse-mode and 224.2.2.2 is using Dense !
> > PIM Sparse Dense is configured on all Frame-relay
> interfaces and the
> > tokenring interfaces.
> > On the tokenring interface of R2 are the two igmp
> joins configured.
> >
> > R1 and R4 are showing the RP (sh ip pim rp
> mapping)
> > R1 can ping 224.1.1.1 and 224.2.2.2
> > R4 can only ping 224.2.2.2
> >
> >
> > What's wrong with this picture !
==========================================================
>>The previous discussion about multicast made me think about a problem I
> >>see occasionally and I thought I'd pass it along. Don't use anything in
> >>the 224.0.0.x range for a multicast address. It will work fine if the
> >>source and destination are in the same vlan (unless you're using one of
> >>the reserved addresses, such as 224.0.0.10 for eigrp, which would
> >>probably wouldn't be a good thing to do... ;-). The reason it doesn't
> >>work when routing multicast is the 224.0.0.x is a "link-local" address,
> >>it never gets forwarded off the local segment, you will never get ip
> >>multicast for 224.0.0.x to work across a router unless you bridged it
> >>(haven't tried it but it should work).
> >>
> >>Most people wouldn't use 224.0.0.x but I see it happen occasionally and
> >>wanted to help save some people the grief of troubleshooting the problem
> >>if you used that range of addresses by mistake. Another common problem
> >>in production networks is many multicast servers have a default ttl of 1
> >>and, since one of the first things a router does is decrement the ttl by
> >>one, the packets get dropped at the router. The solution is to increase
> >>the ttl of the multicast server to be at least one higher than the
> >>number of hops to the furtherest multicast receiver.
> >>
> >>Brian
============================================================
Brian Hescock <bhescock@cisco.com>
> Sent by: nobody@groupstudy.com
> 31-10-2001 14:26
> Please respond to Brian Hescock
>
>
> To: Sijbren
> Beukenkamp/Netherlands/IBM@IBMNL
> cc: ccielab@groupstudy.com
> Subject: Re: Multicast Sparse-Dense
> Mode
>
>
>
> Pinging from R1 means the packets will be
> process-switched. When pinging
> from R4 the packets on R1
> will be fast-switched. Configure "no ip
> mroute-cache" on the outgoing
> interface on R1 and then see
> if you can ping from R4. If not, put an ip igmp
> join-group on the
> outgoing interface on R1 and see
> if you can ping from R4 and get a response from R1.
>
> There have been several multicast fast-switching
> bugs where sometimes you
> don't even get an
> interface in the OIL when you have a join-group
> command on that interface.
> As a workaround, what
> will often work is removing join-group and remove
> pim, let pim timeout
> then put the commands back
> on. If that doesn't work, do the same thing again
> but once the commands
> are off the interface do a
> "shut", wait a few seconds, do a "no shut" and put
> the commands back on
> the interface. You should
> then see the outbound interface in the OIL. This
> isn't something you
> should have to do, just a
> workaround due to a multicast fast-switching bug.
>
> Brian
>
> Sijbren Beukenkamp wrote:
>
> > Consider the following.
> >
> > Three routers R2, R1 and R4. All interconnected
> using FR. R1 is in the
> > centre and will have to route Multicast between
> its serial interface to
> R2
> > and R4. R2 and R4 have a tokenring interfaces at
> which SD-mode is
> > configured. The same is for all the serial
> interfaces.
> >
> >
>
LAN--------R2-------------FR---------------R1----------FR---------------R4--
-
-----LAN
> >
> > IP MULTICAST-ROUTING IP
> MULTICAST-ROUTING IP
> MULTICAST-ROUTING
> > PIM-S-D
> PIM-S-D PIM-S-D
> > igmp-join 224.1.1.1
> > 224.1.1.1 announced by RP
> > igmp-join 224.2.2.2
> >
> > R2 is RP and mapping agent ONLY for 224.1.1.1. So
> basicly 224.1.1.1 is
> > using Sparse-mode and 224.2.2.2 is using Dense !
> > PIM Sparse Dense is configured on all Frame-relay
> interfaces and the
> > tokenring interfaces.
> > On the tokenring interface of R2 are the two igmp
> joins configured.
> >
> > R1 and R4 are showing the RP (sh ip pim rp
> mapping)
> > R1 can ping 224.1.1.1 and 224.2.2.2
> > R4 can only ping 224.2.2.2
> >
> >
> > What's wrong with this picture !
> >
> > Met vriendelijke groet/ Kind regards,
> > Sijbren
> >
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> > Ing. Sijbren Beukenkamp IBM Global Services
> > Internetworking Specialist Integrated
> Technology Services
> >
> Networking & Connectivity
> > Services
> >
> http://www.ibm.com/services/nc/
> > GSM +31 (0)6 53761703 The Netherlands
> > Office: +31 (0)30 2850 666
>
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