Hi,
1. Who generates multicast packets - Is it source OR receiver OR both ?
It depends on what type of packet are we talking about. A control plane packet (like PIM join, mLDP label mapping etc) will be sent from router connecting receivers (aka Last Hop Router) towards:
a. the router connecting the source (aka First Hop Router) if PIM join is sent for (S,G).
b. the RP if it PIM join is sent for (*,G)
2. (S,G) - Does this entry travel in multicast packet ? I want to know it travel source to receiver OR receiver or source ?
- It is sent from Last Hop Router connecting the receivers towards the source and this information is carried in PIM Join message.
3. (*,G) this travel from source to RP or receiver to RP ?
- Same as above. receiver to RP.
