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Jim R

3750X IPBASE And GhostCast Server

Hi all,

I imagine this question has been posted a million times before but here goes.  I am trying to image a number of machines via GhostCast server across a 3750X stack running multiple VLANS.  I am running the IPBASE image so am aware that multicast functionality is limited however I was hoping someone could help me work around the issue.

I am running 12.2(55)SE3.

I have tried adding both VLAN's into an IGMP group using the "ip igmp join-group" command which shows both VLANs as part of the group but to no reall effect.  To be honest though I am clutching at straws!  I'm just starting to read through the documentation so hopefully that will help.

In the meantime any help would be appreciated!


Alessio Andreoli

Did you try to use the all-hosts multicast address? The could (never tried) work without building the tree

Let me know


Peter Paluch
Hall of Fame Cisco Employee

Jamie and Alessio,

Alessio, if we are dealing with inter-VLAN multicast (i.e. the multicasts are originated in one VLAN and are supposed to be delivered into another VLAN) then using the address will not help - apart from this IP address being purposefully defined with link local scope (i.e. not allowed to address any station on a different interface), no router will carry any multicast packet from one interface to another without multicast routing support.

I shall have a look into the docs as well. However, without multicast routing support, the only feasible way of doing this is to perform directed broadcasting.

Best regards,


Jim R

I think I've found a way round the issue using a stub IGMP type configuration. 

On the router I set the following commands:

ip multicast-routing distributed
ip pim rp-address < -- address of ghostcast server

On each VLAN involved in ghosting
ip pim passive
ip igmp helper-address <-- address of ghostcast server

Seems to do the job, a sh ip mroute shows the dynamically built IGMP groups in use (Normally different each time ghostcast server starts) and the client app finds the session name without any prompting.

Cheers all, Let me know if the above helps you at all.