I'm currently designing a terminal-server architecture, using KVM-Over-IP technology (I'm using Gefen devices) where I have four VLANs:
- One VLAN for the displays at 192.168.240.0/24
- Three VLANs for the servers. Why three? Because there are three kinds of servers and they're grouped together. This is imposed and cannot be changed. They're at .241.0, .242.0 and .243.0 respectively.
I'm using a Cisco 3750G Layer 3 Switch. I've configured all the VLANs with their gateways (.1) and there's proper connectivity between the devices. So far so good. The configuration is as follows (this is an excerpt, the rest are the default values)
ip routing ! interface GigabitEthernet1/0/1 switchport access vlan 2 ! interface GigabitEthernet1/0/2 switchport access vlan 10 ! interface GigabitEthernet1/t0/3 switchport access vlan 20 ! interface GigabitEthernet1/0/4 switchport access vlan 30 ! interface Vlan2 ip address 192.168.240.1 255.255.255.0 ! interface Vlan10 ip address 192.168.241.1 255.255.255.0 ! interface Vlan20 ip address 192.168.242.1 255.255.255.0 ! interface Vlan30 ip address 192.168.243.1 255.255.255.0 !
Now, the KVM devices (these Gefen DVI KVM devices) cannot auto discover other KVM devices in different VLANs. That's to be expected, because broadcast messages do not cross VLAN boundaries. After further investigation, looks like these devices use multicast groups to annonunce themselves, using standard TCP connections afterwards to stablish the video transmission.
In order to fix the problem, I've enabled
multicast-routing distributed and also tried activating sparse-dense mode. Using wireshark with port mirroring I can see some
Membership Report messages from the devices within a VLAN, and
PIM protocol messages coming from the VLAN interface (.1), but the devices fail to see each other still.
So, from scratch, how should I configure the 3750G so multicast traffic is shared between VLANs?
Edit: So far I've tried setting up multicast-routing as per the manual (section 47-12):
ip multicast-routing distributed
On each vlan interface:
ip pim sparse-dense-mode
IGMP is enabled by default. This does nothing. I've also tried using MVR but I'm not sure if that's the proper tool for it.