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New Member

Understand of some multicast show commands.

Hey,

 

I'm struggling to understand about below multicast show commands. but, some are not in my mind yet. Can someone eraborate if my comment is correct or not?

 

Router# show ip mroute summary

IP Multicast Routing Table
Flags:D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, 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 - Advertised via MSDP, U
- URD, I - Received Source Specific Host Report
Outgoing interface flags:H - Hardware switched
Timers:Uptime/Expires
Interface state:Interface, Next-Hop or VCD, State/Mode

(*, 224.255.255.255), 2d16h/00:02:30, RP 171.69.10.13, flags: SJPC

(*, 224.2.127.253), 00:58:18/00:02:00, RP 171.69.10.13, flags: SJC

(*, 224.1.127.255), 00:58:21/00:02:03, RP 171.69.10.13, flags: SJC

>>> I understanded that there were no available source yet. so, It is still showing as (*.G), is it correct?

(*, 224.2.127.254), 2d16h/00:00:00, RP 171.69.10.13, flags: SJCL
  (128.9.160.67/32, 224.2.127.254), 00:02:46/00:00:12, flags: CLJT
  (129.48.244.217/32, 224.2.127.254), 00:02:15/00:00:40, flags: CLJT
  (130.207.8.33/32, 224.2.127.254), 00:00:25/00:02:32, flags: CLJT
  (131.243.2.62/32, 224.2.127.254), 00:00:51/00:02:03, flags: CLJT
  (140.173.8.3/32, 224.2.127.254), 00:00:26/00:02:33, flags: CLJT
  (171.69.60.189/32, 224.2.127.254), 00:03:47/00:00:46, flags: CLJT

>>> according to above, various source IP addresses(sender) are transmitting the multicast traffic with single multicast group. my understanding is correct? if so, I don't understand why many source IPs are populated. I thoughted one source should be equaled to one multicast IP.

Pls, clarify me if I'm wrong. for example, 128.9.160.67 is client IP or not, source IP(traffic sender) ?

 

The following is sample output from the show ip mroute command with the active keyword:
Router# show ip mroute active

Active IP Multicast Sources - sending >= 4 kbps

Group: 224.2.127.254, (sdr.cisco.com)
   Source: 146.137.28.69 (mbone.ipd.anl.gov)
     Rate: 1 pps/4 kbps(1sec), 4 kbps(last 1 secs), 4 kbps(life avg)

Group: 224.2.201.241, ACM 97
   Source: 130.129.52.160 (webcast3-e1.acm97.interop.net)
     Rate: 9 pps/93 kbps(1sec), 145 kbps(last 20 secs), 85 kbps(life avg)

Group: 224.2.207.215, ACM 97
   Source: 130.129.52.160 (webcast3-e1.acm97.interop.net)
     Rate: 3 pps/31 kbps(1sec), 63 kbps(last 19 secs), 65 kbps(life avg)

1 ACCEPTED SOLUTION

Accepted Solutions

(*,G) is sparse-join/rpt-join

(*,G) is sparse-join/rpt-join/pim join and it represents a/some receivers have joined the group. This is forwarded hop-by-hop from last-hop router (connected to the receiver) to the RP(rendezvous point)

 

(S,G) represents the Source/Sender and the Group and builts the shortest path tree(SPT). There can be multiple senders for the same groups. All senders must register to the RP.

 

IP Mcast technology overview

http://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/ip_multicast/White_papers/mcst_ovr.html

Quick Config Guide

http://www.cisco.com/c/en/us/support/docs/ip/ip-multicast/9356-48.html

Troubleshooting Guide

http://www.cisco.com/c/en/us/support/docs/ip/ip-multicast/16450-mcastguide0.html

 

-Vishesh

2 REPLIES
New Member

Hi,you are using PIM Sparse

Hi,

you are using PIM Sparse Mode and from what I recall, by default, a shared tree is built for that multicast group but if the cost direct to the source is better than going through the RP, then specific source trees are built.

Mario

(*,G) is sparse-join/rpt-join

(*,G) is sparse-join/rpt-join/pim join and it represents a/some receivers have joined the group. This is forwarded hop-by-hop from last-hop router (connected to the receiver) to the RP(rendezvous point)

 

(S,G) represents the Source/Sender and the Group and builts the shortest path tree(SPT). There can be multiple senders for the same groups. All senders must register to the RP.

 

IP Mcast technology overview

http://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/ip_multicast/White_papers/mcst_ovr.html

Quick Config Guide

http://www.cisco.com/c/en/us/support/docs/ip/ip-multicast/9356-48.html

Troubleshooting Guide

http://www.cisco.com/c/en/us/support/docs/ip/ip-multicast/16450-mcastguide0.html

 

-Vishesh

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