Multicast Routing -- What's the Big Deal?

Hi,

To simplify--I have a small but relatively complex network. My core is a pair of FortiGate firewalls that handle Layer 3. My access layer is Layer 2 only. It hosts multiple VLANs--about 8--on two stacks and three singleton top-of-rack switches. Platforms: routing is FortiGate; switching is Cisco: Meraki, Nexus, Catalyst to be added later.

After deployment I handed the network over to a managed services provider, for better or for worse.

I have a requirement for IPTV, based on multicast. It works fine now within a VLAN, but I have to route multicast traffic from the IPTV segment to a user segment.

I confess near-total ignorance of multicast. The MSP is acting like this will be a big-deal redesign and downtime-requiring deployment.

Can you give me the gist (high level) of what enabling multicast routing typically entails and whether it is, indeed, a bid deal, requiring downtime?

Thanks.