[c-nsp] Same multicast flow with multiple source

[David Prall]

This is why it is called Any Source Multicast (ASM). A number of
applications use the same group for discussions. Cisco's old IP/TV
distributed over one group, then had a second group for feedback. So as you
typed in a question it was sent to everyone.

David

--
http://dcp.dcptech.com


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Riccardo S
Sent: Monday, December 17, 2012 12:03 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] Same multicast flow with multiple source




I built up a PIM connection to a new multicast
provider and I see this provider is sending the same mcast flow with some
different sources:

 --------------

xx#sh ip mroute 224.0.1.114 count 

IP Multicast Statistics

858 routes using 542426 bytes of
memory

705 groups, 0.21 average sources per
group

Forwarding Counts: Pkt
Count/Pkts(neg(-) = Drops) per second/Avg Pkt Size/Kilobits per second

Other counts: Total/RPF failed/Other
drops(OIF-null, rate-limit etc)

 

Group: 224.0.1.114, Source count: 4,
Packets forwarded: 9106926, Packets received: 9106926

 
RP-tree: Forwarding: 31/0/37/0, Other: 31/0/0

 
Source: 172.16.89.2/32, Forwarding: 10994/0/30/0, Other: 10994/0/0

 
Source: 172.16.89.6/32, Forwarding: 10994/0/30/0, Other: 10994/0/0

 
Source: 172.16.89.3/32, Forwarding: 9073913/27/299/63, Other: 9073913/0/0

 
Source: 172.16.89.5/32, Forwarding: 10994/0/30/0, Other: 10994/0/0

---------------

 

Questions:

1)      From a conceptual point of view is it
correct they send same feed with a lot of different sources ? Usually I
always
saw one A feed (with sourceA,GroupA) and one B feed (with sourceB,GroupB)...

2)      Which can be the reason whether they
send one flow with different pkt size (299Byte) and all the other with
30byte
pkt size ?

3)      Since on my CPE I have static
join towards the group in this way I'll get the flow four times with
bandwidth
exceeded ? Is there a method to us only one flow if identical to the others
?

 

Tks

 		 	   		  
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