From: Snow, Tim (timothy.snow@eds.com)
Date: Mon Jun 16 2003 - 03:49:03 GMT-3
Hey all, trying to get my arms around Multicast. I set up a little topology
to go over the different parts of PIM. Here's the setup (steps below)
r7====two ethernets=====r8------FR----R2---224.1.1.1
192.168.78.0 & 87.0
PIM Dense is up and running and I have "ip igmp join-group 224.1.1.1" on the
ethernet interface of r2. On r7, (step 1) I issued the "sho ip mroute"
and would have expected that I would have atleast seen a unused (*, G) entry
which I think is used as a placeholder (can anyone comment) When I did a
ping (step 2), I'm guessing that r7 sent out a join for the 224.1.1.1
group and then adds a state entry when it's up (step 3) Does active data
trigger the timer to reset to 3, or would the r7 router generate join's
every 1 minute if it had a client that wanted the stream that was directly
connected?
After a couple of minutes (i'm guessing 3) the (S,G) 's are purged out, and
it looks like the (*,G)'s timer has started now that there is now (S,G) with
active outgoing interfaces. But then in step 5, it looks like the (*,G)
times out too as it no longer exists in the mroute table.
If anyone can comment on this, I'd really appreciate it. Thanks.
Tim
1)
r7#sh ip mroute
(*, 224.0.1.40), 00:34:00/00:00:00, RP 0.0.0.0, flags: DJCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Ethernet3, Forward/Dense, 00:33:44/00:00:00
Ethernet2, Forward/Dense, 00:34:00/00:00:00
2)
r7#ping 224.1.1.1
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 224.1.1.1, timeout is 2 seconds:
04:58:21: MRT: Create (*, 224.1.1.1), RPF Null, PC 0x6067CF6C
04:58:21: MRT: Add/Update Ethernet2/224.1.1.1 to the olist of (*,
224.1.1.1), Forward state
04:58:21: MRT: Add/Update Ethernet3/224.1.1.1 to the olist of (*,
224.1.1.1), Forward state
04:58:21: MRT: Create (192.168.78.7/32, 224.1.1.1), RPF Ethernet2/0.0.0.0,
PC 0x6067D178
04:58:21: MRT: Add/Update Ethernet3/224.1.1.1 to the olist of (192.168.78.7,
224.1.1.1), Forward state
04:58:21: MRT: Create (192.168.87.7/32, 224.1.1.1), RPF Ethernet3/0.0.0.0,
PC 0x6067D178
04:58:21: MRT: Add/Update Ethernet2/224.1.1.1 to the olist of (192.168.87.7,
224.1.1.1), Forward state
Reply to request 0 from 192.168.1.2, 80 ms
Reply to request 0 from 192.168.1.2, 168 ms
After the ping, the mroute table is populated....
3)
r7#sh ip mroute
(*, 224.0.1.40), 00:36:37/00:00:00, RP 0.0.0.0, flags: DJCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Ethernet3, Forward/Dense, 00:36:21/00:00:00
Ethernet2, Forward/Dense, 00:36:37/00:00:00
(*, 224.1.1.1), 00:02:08/00:02:59, RP 0.0.0.0, flags: D
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Ethernet3, Forward/Dense, 00:02:08/00:00:00
Ethernet2, Forward/Dense, 00:02:08/00:00:00
(192.168.78.7, 224.1.1.1), 00:02:08/00:00:51, flags: PT
Incoming interface: Ethernet2, RPF nbr 0.0.0.0
Outgoing interface list:
Ethernet3, Prune/Dense, 00:02:10/00:00:49
(192.168.87.7, 224.1.1.1), 00:02:10/00:00:49, flags: PT
Incoming interface: Ethernet3, RPF nbr 0.0.0.0
Outgoing interface list:
Ethernet2, Prune/Dense, 00:02:10/00:00:49
After a couple of minutes
4)
r7#sh ip mroute
(*, 224.0.1.40), 00:40:23/00:00:00, RP 0.0.0.0, flags: DJCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Ethernet3, Forward/Dense, 00:40:07/00:00:00
Ethernet2, Forward/Dense, 00:40:23/00:00:00
(*, 224.1.1.1), 00:05:54/00:00:05, RP 0.0.0.0, flags: D
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Ethernet3, Forward/Dense, 00:05:54/00:00:00
Ethernet2, Forward/Dense, 00:05:54/00:00:00
And after 5 more seconds, It goes away....
5)
r7#sh ip mroute
(*, 224.0.1.40), 00:41:56/00:00:00, RP 0.0.0.0, flags: DJCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Ethernet3, Forward/Dense, 00:41:40/00:00:00
Ethernet2, Forward/Dense, 00:41:56/00:00:00
r7#
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