Multicast domains
Q: if routers peer each other throughout the Internet, how can you confine multicast traffic for some applications to a given domain/set of routers?
- First Answer: TTL thresholds
- define a multicast TTL (Time To Live) threshold on the interfaces of your router(s)
- multicast packets whose TTL is less than the threshold will be discarded
- if multicast applications generate packets with the proper TTL, then the TTL threshold mechanism can be used to define multicast domains
- Second Answer: per-interface, per-group-of-addresses multicast boundaries