[c-nsp] Cisco 3560G ip routing and multicast ?

[Xavier Beaudouin]

Hello,

We like to understand how multicast is handled with Cisco 3560G in a
very special case : when we don't enable multicast routing in the  device.

Problem is :

- we have more than 100 machines in a /25 that does multicast using
  pim sparse-dense mode.
- we have several 3560G with 2 (maybe more in the future) vlan with
  !
  ip multicast-routing distributed
  ip igmp snooping vlan 10 immediate-leave
  ip igmp snooping vlan 20 immediate-leave
  !
  interface vlan10
    ip address 10.2.2.201 255.255.255.0
    ip pim sparse-mode
  !
  interface vlan20
    ip address 10.2.3.201 é55.255.255.0
    ip pim sparse-mode
  !

We like to add a dedicated 3560G to do the IP Unicast routing only :
  !
  interface vlan10
    ip address 10.2.2.254 255.255.255.0
  !
  interface vlan20
    ip address 10.2.3.254 é55.255.255.0
  !

Problem is that this device will receive the multicast (we have about
200 / 300 Mbps of multicast in general).

How will be handled the multicast ? does packets will goes into CPU
before discarded ?

Unicast traffic will be less than 1 or 2% of bandwith in general on each
ports...

Thanks for yours informations.

/Xavier