My network is router less then i think i've not to configure igmp querier,
You must have an IGMP querier. If you do not have a router, most switches can be configured to do this instead.
However, your environment is a little unusual because of the presence of the gigabit trunk between the core switches. Also, when you have VLANs, you do have routing! In your case because you do not have an external router, you have configured the switches to do the routing.
In the diagram you have the core switches labeled 4500G - this is the
3Com 4500G?
I don't know how to configure the 4500G for multicast routing, but it does have a special feature called "Multicast VLAN" feature to join the individual VLANs back into a single LAN for multicast purposes.
This is discussed in the
4500G Configuration Guide, chapter 31.
Because your environment is routed, but you have used the switches to do this, and because you have multiple VLANs and multiple switches, it may be best if you discuss this with a 3Com support engineer.
then do i have to configure igmp snooping on each switch and each vlan ?
Yes, that is normally what you have to do in switches that support VLANs, although some vendors have special combinations of arrangements.
With the 4500G specifically, the multicast VLAN option of the switch is set up differently to other switches. It's a good concept, but it's specific to 3Com and because your environment is unusual you should discuss this with 3Com support to see if it can be used in your environment.
For a normal network with a separate router, you configure snooping both by enabling it globally and then per-VLAN, as described in the
4500G Configuration Guide, chapter 30, page 329, table 227
system-view
igmp-snooping
quit
vlan vlan-id
igmp-snooping enable
since i change parameters of the network card of my ghost server, a lot of clients are not seen by the console.
The clients use multicast to try and locate your Ghost server. If you have multicast working properly, then nothing else is required.
If your clients are on separate networks (including VLANs) from the console, then you need to have correctly configured multicast routing (or use something like the 3Com 4500G's "multicast VLAN" to join the separate VLANs back together for multicast).