I'm not going to spend a lot of time on re‑examining
packet captures in IPv6 that aren't significantly
different than their IPv4 counterparts,
but let's level set the basic PIM packets in IPv6 any‑source multicast.
The PIM Hello is sent to the ALL‑PIM‑ROUTERS IPv6 group ff02::d,
which indicates a link‑local group.
In binary, this would be 224.0.0.13, and since binary 13 is hex d,
that makes sense.
The only real difference is Option 2,
which adds the ability to propagate different join and prune timers.
These timers are communicated through the PIM Hellos and can be used to
adjust how quickly PIM can re‑converge if there are changes.
They also added Option 24 in IPv6,
and that can be used to communicate any secondary
addresses assigned to the interface.
In IPv6,
it's supported and not uncommon to have multiple networks on the same interface.
The option will be empty if there are no secondary addresses,
but otherwise would contain a list of secondary addresses.
The PIM Register is pretty much identical to the IPv4 equivalent.
This register packet is being unicast to the RP address over the PIM tunnel,
the PIM packet denotes this as a register,
and what follows is the encapsulated multicast stream itself,
in this case, an ICMP v6 packet.
If the RP has no active PIM joins,
it sends a register stop message to the first‑hop router,
asking it to stop delivering the encapsulated multicast stream.
We can see the registered stop is a Unicast message and that it indicates
the multicast group and source to cease delivery for.
The RP then keeps those details in case a PIM join is received
interested in that group. The PIM Join/Prune in IPv6 is very
similar to the IPv4 equivalent.
This join from packet is a *, G PIM join for the group ff04:2003:2::1. Notice
the requested source is the RP address, as well as the flags,
Sparse, WildCard, and Rendezvous Point Tree.
In this module, we covered the following. We recapped how any‑source
multicast works and what's new for IPV6. Specifically, we talked about
multicast scoping and the embedded RP feature.
We saw demonstrations of sending IPv6 multicast traffic
and how the embedded RP works as well.
Finally, we spent some time reinvestigating PIM packets in IPV6 to see the differences.