multicasting_in_3750switch_not_receiving_in_all_Vlans

[secureIT]

Hi All,

I have a cisco 3750 48 port switch with 7 vlans created. I have configured multicasting in the switch. Multicasting transmission server is connected in one vlan(vlanT) and receivers are connected in other vlans(VlanRs).

I test the multicasting with the use of Wireshark software(similar to ethereal). I am getting 239.x.x.x traffic only when i connect to VlanT.

I am not getting multicast streams in other vlans...I am using the software ipservices-mz-122.25.SEE4. I tried with other ios also. no success

Configurations..

ip routing

ip multicast-routing distributed

no ip igmp snooping

interface vlanT

ip address x.x.x.x

ip pim dense mode

interface VlanRs

ip address x.x.x.x

ip pim dense mode

Could some one help me on this....

I checked with other pim modes, version etc...

regards

Rajesh

[Harold Ritter]

Rajesh,

What is the TTL value set on the test multicast packets you are sending. A common issue is that packets are sent with a TTL value of 1, which means that they will not be seen beyond the local subnet.

Regards,

[secureIT]

Hi,

Okay, I have to check the TTL value. Could you tell me what should be the value set on the multicasting server?

Regards

Rajesh

[cisco_lad2004]

it all depends if u want to have security, so ur packets do not go over a certain radius or number of multicast hops.

You could pick a value that is the number of hops between your farthest client and your application.

else if you want to troubleshoot, set it to 25 or 30 and watch if it improves, then start reducing it ( so u have it working + security).

HTH

Sam

[Harold Ritter]

Rajesh,

In your current scenario, it looks like you only that one device involved, right? In this case setting the TTL to 2 will be fine.

Regards,

[rsohi]

Rajesh, I notice that you have defined the pim mode but not the pim rendevous point. You may have to add the statement 'ip pim rp x.x.x.x' in order for pim to work properly. Give the address of one of your vlan interfaces (ie. vlanT interface ip address).

Also, I notice that you have to 'no ip igmp snooping' command in your show run. With this command you will be sending multicast through to all the ports and not the ones that actually are members of a multicast group, which is adding additional traffic to your switch.

hope this helps,

Raj

[Harold Ritter]

Raj,

There is no need for an RP as Rajesh configured the interfaces in dense mode.

Regards,