From: Chris Lewis (chrlewiscsco@gmail.com)
Date: Wed Feb 01 2006 - 11:46:01 GMT-3
The configuration with sparse mode only for this case is correct and works
fine. either this is not a complete representation of the question, or the
question itself is not correct, as you should expect pings to 239.0.0.1 to
work in this setup.
First look at the output of show ip pim rp map and you should see that all
routers see 9.9.9.3 as the RP for the 239.0.0.0/8 group elected via auto-rp.
So the question is how did that happen? Well all Cisco routers join the
224.0.1.40 group by sending an IGMP join. R3 will see those joins and use it
to disseminate RP information as it is directly connected. R5 will send
pings out all interfaces regardless of PIM configuration, so everything gets
to R3.
If you moved the RP to R2 for example, you lose the directly connected
relationship (for the link local 224.0.1.40) and the ping from R5 will fail.
Chris
On 2/1/06, my-ccie-test@libero.it <my-ccie-test@libero.it> wrote:
>
> Hi all,
> I did a multicast lab and I had an unexpected behavior on auto-rp
> configuration.
> the target of the lab was to check the behavior of auto-rp in a pim
> sparse-mode cloud and add the command auto-rp listener to work with a
> auto-rp rp and a sparse-mode cloud.
> So teh steps of this lab are:
>
> 1) configure sparse-mode cloud with a static rp
>
> 2) join the group 239.0.0.1 on one router and source this gorup from
> another router, check if the joining router respond to a ping.
>
> 3) delete static rp and configure auto-rp, leave the cloud pim sparse-mode
>
> 4) make a ping from a source to 239.0.0.1, the expected beahvior is that
> no router respond to the ping.
>
> 5) configure auto-rp listener on all routers and repeat the ping.
>
> I did not arive at step 5 because I had an unexpected result on step 4.
>
> infact, when I did a ping with auto-rp in pim sparse-mode cloud, the ping
> was successfull!!!
> I thought the auto-rp requires only sparse-dense-mode cloud...
> checking the mroute table on all routers all work fine.
>
>
> any thoughts?
> thanks in advance
>
> Max
>
> here are the network and config.
>
>
> |---r2
> r5----r3----|
> |---r1
>
>
> r3 is the rp
> r5 is the source of 239.0.0.1
> r1 join the group 239.0.0.1
> there is only one strange message I received on all routers is
>
> 17:37:19: %PIM-6-INVALID_RP_JOIN: Received (*, 224.0.1.40) Join from
> 10.0.2.2 for invalid RP 10.0.0.101
>
> here are the config
>
> --------------------------------------------
> r5
>
> interface Loopback0
> ip address 10.0.0.101 255.255.255.252
> ip pim sparse-mode
> !
> !
> interface FastEthernet0/0
> ip address 10.10.10.5 255.255.255.0
> ip pim sparse-mode
> duplex full
> speed 100
> !
>
> ---------------------------------------------
>
> r3
>
> !
> interface Loopback0
> ip address 9.9.9.3 255.255.255.255
> no ip directed-broadcast
> ip pim sparse-mode
> !
> !
> interface Ethernet0
> ip address 10.10.10.3 255.255.255.0
> no ip directed-broadcast
> ip pim sparse-mode
> media-type 10BaseT
> !
> !
> interface Ethernet3
> ip address 10.0.2.3 255.255.254.0
> no ip directed-broadcast
> ip pim sparse-mode
> media-type 10BaseT
> !
> ip pim send-rp-announce Loopback0 scope 255 group-list 1
> ip pim send-rp-discovery Loopback0 scope 255
> !
> access-list 1 permit 239.0.0.0 0.255.255.255
> !
>
> -------------------------------------------------------------------
>
> r2
>
> !
> interface Loopback0
> ip address 9.9.9.2 255.255.255.255
> no ip directed-broadcast
> ip pim sparse-mode
> !
> !
> interface Ethernet0/0
> ip address 10.0.2.2 255.255.254.0
> no ip directed-broadcast
> ip pim sparse-mode
> !
> --------------------------------------------------------------------
>
> r1
>
> !
> interface Loopback1
> ip address 10.0.255.1 255.255.255.255
> no ip directed-broadcast
> ip pim sparse-mode
> ip igmp join-group 239.0.0.1
> !
> !
> interface Ethernet1/1
> ip address 10.0.2.1 255.255.254.0
> no ip directed-broadcast
> ip pim sparse-mode
> !
> ----------------------------------------------------------------------
>
>
> ping from r5 to 239.0.0.1
>
> r5#p 239.0.0.1
>
> Type escape sequence to abort.
> Sending 1, 100-byte ICMP Echos to 239.0.0.1, timeout is 2 seconds:
>
> Reply to request 0 from 10.0.2.1, 4 ms
> Reply to request 0 from 10.0.2.1, 4 ms
> r5#
>
> show ip mroute on r5
>
> r5#sh ip mroute
> IP Multicast Routing Table
> Flags: D - Dense, S - Sparse, C - Connected, L - Local, P - Pruned
> R - RP-bit set, F - Register flag, T - SPT-bit set, J - Join SPT
> M - MSDP created entry, X - Proxy Join Timer Running
> A - Candidate for MSDP Advertisement
> Outgoing interface flags: H - Hardware switched
> Timers: Uptime/Expires
> Interface state: Interface, Next-Hop or VCD, State/Mode
>
> (*, 224.0.1.39), 01:11:40/00:02:59, RP 0.0.0.0, flags: DJC
> Incoming interface: Null, RPF nbr 0.0.0.0
> Outgoing interface list:
> FastEthernet0/0, Forward/Sparse, 01:11:40/00:02:47
>
> (9.9.9.3, 224.0.1.39), 00:02:35/00:00:24, flags: PCT
> Incoming interface: FastEthernet0/0, RPF nbr 10.10.10.3
> Outgoing interface list: Null
>
> (*, 224.0.1.40), 01:11:48/00:00:00, RP 0.0.0.0, flags: DJCL
> Incoming interface: Null, RPF nbr 0.0.0.0
> Outgoing interface list:
> Loopback0, Forward/Sparse, 01:11:48/00:02:25
> FastEthernet0/0, Forward/Sparse, 01:11:48/00:02:41
>
> (9.9.9.3, 224.0.1.40), 01:11:35/00:02:55, flags: CLT
> Incoming interface: FastEthernet0/0, RPF nbr 10.10.10.3
> Outgoing interface list:
> Loopback0, Forward/Sparse, 01:11:35/00:02:25
>
> (*, 239.0.0.1), 00:00:17/00:02:59, RP 9.9.9.3, flags: SPF
> Incoming interface: FastEthernet0/0, RPF nbr 10.10.10.3
> Outgoing interface list: Null
>
> (10.0.0.101, 239.0.0.1), 00:00:17/00:02:42, flags: FT
> Incoming interface: Loopback0, RPF nbr 0.0.0.0, Registering
> Outgoing interface list:
> FastEthernet0/0, Forward/Sparse, 00:00:18/00:03:11
>
> (10.10.10.5, 239.0.0.1), 00:00:18/00:02:41, flags: PFT
> Incoming interface: FastEthernet0/0, RPF nbr 0.0.0.0
> Outgoing interface list: Null
>
> r5#
>
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