Multicast Question 3750

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Apr 26th, 2010
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Hello All,

I have a question about a simple multicast setup with a 3750 (IP Services) and a multicast capable camera.  I have 2 VLANs configured.

Vlan 6

Vlan 7

The camera is connected to a port in VLAN 7 and is configured with the following IP addresses:

If I configure a laptop with and connect it to a port in VLAN 7 I can pull a multicast stream from the camera.

Next I wanted to view the same stream from a laptop connected to a port on VLAN 6.  From what I have read and understand about multicasting between subnets I enabled multicast routing on the 3750.  I also enabled pim sparse mode on each VLAN.

Unfortuenately I am unable to pull the stream from a laptop on VLAN 6.  I enabled debug and it looks as if the 3750 is receiving the join request from VLAN 6 but the stream never kicks off.  

Am I going about this correctly?  Thanks in advance for any help you can provide.

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Reza Sharifi Mon, 04/26/2010 - 16:54
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Hi Dan,

On what ever application you are using to display the multicast on your PC, make sure if there is a setting for TTL, you set it to more then 1 and try again.

I use VLC media player for testing multicast and if the multicast and the PC are in differnt vlans, I need to raise the TTL to minimum 2



markanthony Mon, 04/26/2010 - 17:12
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Did you enable multicast globally?  What happens if you use dense mode?  For sparse mode you have to have an RP for a given multicast group/mask.  

Try explicitly adding it

ip pim send-rp-announce vlan 7 scope 16 group-list 1

ip access-list standard 1
what do you see when you do a "show ip mroute" when you get camera stream going and trying to listen to stream on both PCs?
danieljdiluzio Tue, 04/27/2010 - 08:22
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Thank you all for taking the time to respond.  I tried both suggestions but they did not work.  I then installed VLC on one of the laptops and setup an avi file to stream.  From the other laptop I was able to open the stream just fine.  It appears to be an issue with the application.  To stream from this camera one must first access the camera via its unicast IP.  Then there is an option to initiate a multicast stream (a multicast address was configured in the camera setup beforehand).  Thanks again.


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