Subject: [pim] question about register of cisco routers

From: "Nescafe" <[email-masked]>
Date: Wed, 24 Oct 2001 17:59:40 +0800

hi,all
    I did an experiment on two directly-connected cisco routers to find out
the action of pim data registeration. But the debug infomation is not clear
to me.

    I send icmp packets from loopback1(67.1.1.1/255.0.0.0) of source, RP(41
1.1.2) is a local address of destination router
please look at the texts I get:

source:
18:31:48: MRT: Create (67.1.1.1/32, 224.1.1.123), RPF Loopback1/0.0.0.0, PC
0x3380D04
18:31:48: PIM: Send v2 Register to 41.1.1.2 for 67.1.1.1, group 224.1.1.123
18:31:48: IP: s=67.1.1.1 (Loopback1) d=224.1.1.123 len 100, mroute olist
null
18:31:48: PIM: Send v2 Register to 41.1.1.2 for 67.1.1.1, group 224.1.1.123
18:31:48: IP: s=67.1.1.1 (Loopback1) d=224.1.1.123 len 100, mroute olist
null
18:31:48: PIM: Received v2 Join/Prune on Serial1 from 41.1.1.2, to us
18:31:48: PIM: Join-list: (67.1.1.1/32, 224.1.1.123), S-bit set
18:31:48: PIM: Add Serial1/41.1.1.2 to (67.1.1.1/32, 224.1.1.123), Forward
state
18:31:48: PIM: Received v2 Join/Prune on Serial1 from 41.1.1.2, to us
18:31:48: PIM: Prune-list: (67.1.1.1/32, 224.1.1.123)  
18:31:49: PIM: Prune Serial1/224.0.0.2 from (67.1.1.1/32, 224.1.1.123) -
deleted
18:31:49: PIM: Send v2 Null Register to 41.1.1.2
18:31:49: PIM: Received v2 Register-Stop on Serial1 from 41.1.1.2
18:31:49: PIM:   for source 0.0.0.0., group 0.0.0.0
18:31:50: PIM: Send v2 Register to 41.1.1.2 for 67.1.1.1, group 224.1.1.123
18:31:50: IP: s=67.1.1.1 (Loopback1) d=224.1.1.123 len 100, mroute olist
null

destination:
18:41:26: PIM: Received v2 Register on Serial1 from 41.1.1.1
18:41:26:      for 67.1.1.1, group 224.1.1.123
18:41:26: MRT: Create (67.1.1.1/32, 224.1.1.123), RPF Serial1/41.1.1.1, PC
0x338EE14
18:41:26: PIM: Forward decapsulated data packet for 224.1.1.123 on Ethernet0
18:41:26: PIM: Send v2 Join on Serial1 to 41.1.1.1 for (67.1.1.1/32, 224.1.1
123), S-bit
18:41:26: PIM: Received v2 Register on Serial1 from 41.1.1.1
18:41:26:      for 67.1.1.1, group 224.1.1.123
18:41:26: PIM: Forward decapsulated data packet for 224.1.1.123 on Ethernet0
18:41:26: PIM: Send v2 Prune on Serial1 to 41.1.1.1 for (67.1.1.1/32, 224.1
1.123), S-bit
18:41:26: PIM: Received v2 Register on Serial1 from 41.1.1.1
18:41:26: PIM: Send v2 Register-Stop to 41.1.1.1 for 0.0.0.0, group 0.0.0.0

I don't know why the dest send prune to source, I believe that the out-if of
the source should not be pruned that way. 

Another question: If no data come from source, how to delete the according
(S, G)  ,because we send null-register for this entry and keep it alive.
Even if we don't send null-register, the source can't time out before the
destination, for the latter will send join periodically to keep the state of
the former.

I'm very puzzled with the question, thanks for giving your opinions
and correct mine