lab & test multicast


there’s a couple decent tools to lab & test multicast routing.  one is mcast.exe and the other is VLC.  the third, i suppose, is to join a cisco interface to a multicast group.  dan mentioned a fourth tool, nortel’s multicast hammer.

symantec endpoint protection 11 disabled broadcast & multicast by default.  you will need to disable this if you have it installed.  🙂

mcast.exe is a part of the windows 2003 resource kit.  in windows 7, you need to run your command prompt as administrator for it to work.  on the “source side”, all you need to specify is a source interface/ip-address and multicast group.  i usually test with more packets of obnoxious sizes.  🙂  overriding TTL gives you more testing options.

mcast /intf: /send /grps: /pktsize:65535 /numpkts:20000000000 /ttl:128

on the “destination side”, all you need to specify is a source interface/ip-address and multicast group.

mcast /intf: /recv /grps:

another way to test is with VLC.  i’ve tested this in 0.98 and 1.1.  it’s easier & faster from the command line than the GUI.  on the “source side”, you need to specify a destination multicast group, port, and override the default TTL of 1.

vlc -vvv c:\media\SomeShow.S02E03.720p.HDTV.x264-CTU.mkv –sout udp: –ttl 255 –loop

for the “destination side”, specify a multicast group and port to tune into

vlc udp://

i found an annoying nuance in VLC 1.1 or windows 7 for a client tuning into a multicast stream

vlc udp://@

last but not least, a cisco interface.

sw1(config-if)#do sh run int loopback 153
Building configuration...

Current configuration : 121 bytes
interface Loopback153
ip address
ip pim sparse-mode
ip igmp join-group

verify igmp memberships. maybe check pim rp if you’re up for it:

sw1#sh ip igmp groups
IGMP Connected Group Membership
Group Address Interface Uptime Expires Last Reporter Group Accounted Vlan2 3d02h 00:02:57 Loopback153 00:01:56 00:02:49 Vlan2 27w4d 00:02:52 Vlan2 1w1d 00:02:51 Vlan2 07:09:12 00:02:53 Vlan1 27w4d 00:02:52

Categories : geek

one comment

  1. Holy zonkers! Thanks man! This is like exactly the problem we are having at workz0rz!

    sean.demura, May 30, 2012

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