Cisco – Private vLAN useful to isolate multicast sources

ciscomulticastprivate-vlanswitch

On a Cisco 3750G switch I have a number (30-ish) of video processors in a vLAN providing multicast streams to clients via a router. Because all of the machines are in the same vLAN they see each other's output, this is causing issues because of the high volume of traffic.

Is there a way to isolate the multicast traffic so it isn't sent to all of the peer servers, and just the upstream (yet allow them to be in the same vLAN and see unicast traffic)? I was thinking that a private vLAN for each server/switch-port would do the trick. What would be the side-effects of this? Or can I use multicast blocking?

In the network diagram we have unicast video sources to each server on vLAN 1 (green). The encoders process the video and provide multicast streams (unique per encoder) to clients via vLAN 2 (red) and router 1. IGMP snooping is enabled on switch 2.

The problem is that the very high volume of traffic on the red vLAN is causing issues. A previous Network Engineer tried to resolve this at one location by splitting the red vLAN into multiple vLANs. This seemed to help, but didn't really solve the issue. I would like to know if we make all of the encoder ports in the red network into isolated ports in a private vLAN, so they don't see each other's traffic, would this solve this problem.

enter image description here

The switch config is:

# show running-config

version 12.2
[...]
!
hostname swtch02
!
[...]
system mtu routing 1500
ip routing
!
ip multicast-routing distributed
!
!
port-channel load-balance src-dst-ip
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!
vlan 2
 name video_out
!
interface GigabitEthernet1/0/1
 description encoder-1
 switchport access vlan 2
 switchport mode access
 spanning-tree portfast
!
interface GigabitEthernet1/0/2
 description encoder-2
 switchport access vlan 2
 switchport mode access
 spanning-tree portfast
!
interface GigabitEthernet1/0/3
 description encoder-3
 switchport access vlan 2
 switchport mode access
 spanning-tree portfast
!
interface GigabitEthernet1/0/4
 description encoder-4
 switchport access vlan 2
 switchport mode access
 spanning-tree portfast
[...]
!
interface Vlan2
 ip address 192.168.1.254 255.255.255.0
!
ip classless
ip route 0.0.0.0 0.0.0.0 x.x.x.x
[...]
end

Best Answer

Are the sources using the same multicast address. If not make sure IGMP snooping is enabled on the switch. Private Vlans would prevent the servers from seeing each other even for unicast. If all the sources are using the same multicast address IGMP snooping would still work as long as the servers only transmit, but I am fuzzy.

Related Topic