Answers to your Questions

What are the Main Routing Protocols for IPv6?

As with IPv4, IPv6 uses both IGP (Internal Gateway Protocol) and EGP (External Gateway Protocol) routing protocols.

The EGP protocol is referred to as BGP4+. In fact, BGP4+ uses a specific attribute called Multi-Protocol BGP (MP-BGP) to carry IPv6 routes, known as IPv6 NLRI (Network Layer Reachability Information). BGP4+ is an extension of BGP4, and is compatible with BGP4. For example, BGP4+ could run on both IPv4 and IPv6 protocol stacks.

Different IGP protocols will be available, the most important being ISIS, RIPng, and OSPFv3.

ISIS will be extended as an IPv6 routing protocol, with two new TLVs to carry the information required to perform IPv6 routing. As with BGP, ISIS will carry IPv4 and IPv6 information.

RIP version 1 and RIP version 2 are used for routing IPv4 information. The IPv6 flavor of RIP is called RIPng, aka RIP Next Generation. RIPng is based on RIPv2, and has been extended to support larger IP addresses and multiple addresses on each interface. RIPv2 and RIPng are not compatible.

The OSPF flavor for IPv6 is called OSPF version 3, or OSPFv3. OSPFv3 has many modifications that make it an incremental version of the IPv4 flavor. OSPFv2 and OSPFv3 are incompatible.

Regarding multicast protocols, the equivalent of IGMP for IPv6 - Internet Group Management Protocol - is called MLD, or Multicast Listener Discovery. An IPv6 version of PIM is also currently being defined.