IPv6 Routing Protocols

As in IPv4, IPv6 has 2 families of routing protocols: IGP and EGP, and still uses the longest-prefix match routing algorithm
IGP
RIPng (RFC 2080)
Cisco EIGRP for IPv6
OSPFv3 TLF

Cisco EIGRP for IPv6
Integrated Integrated IS-ISv6 (RFC 5308)
OSPFv3 (RFC 5340 Obsolètes RFC 2740)
EGP : MP-BGP4 (RFC 2858 and RFC 2545)
Cisco IOS supports all of them
Pick one that meets your objectives

RIPng
(RFC 2080)

Similar characteristics as IPv4
Distance-vector, hop limit of 15, split-horizon, multicast based (FF02::9), UDP port
(521) etc.
Updated features for IPv6
IPv6 prefix & prefix len.
Special Handling for the NH
Route tag and prefix len for NH is all 0. Metric will have 0xFF. NH must be link local

EIGRP for IPv6

Just another protocol module (IP, IPX, AppleTalk) with three new TLVs:
IPv6_REQUEST_TYPE (0X0401)
IPv6_METRIC_TYPE (0X0402)
IPv6_EXTERIOR_TYPE (0X0403)
OSPFv3 TLF
Other similarities
Same protocol number 88
Router ID stays 32 bits (must be configured explicitly if there is no IPv4
interface on the router)
Uses MD5 like for IPv4
(IPSec authentication will be available soon)
Same metrics

ISIS for IPv6

 2 Tag/Length/Values added to introduce IPv6 routing
IPv6 Reachability TLV (0xEC)
Describes network reachability such as IPv6 routing prefix, metric information and
some option bits. The option bits indicates the advertisement of IPv6 prefix from
a higher level, redistribution from other routing protocols.
Equivalent to IP Internal/External Reachability TLV’s described in RFC1195
OSPFv3 TLF © 2008 Cisco Systems, Inc. All rights reserved. Cisco Public 47
IPv6 Interface Address TLV (0xE8)
Contains 128 bit address
For Hello PDUs, must contain the link-local address (FE80::/10)
For LSP, must only contain the non link-local address
A new Network Layer Protocol Identifier (NLPID) is defined

Allowing IS-IS routers with IPv6 support to advertise IPv6 prefix payload using
0x8E value (IPv4 & OSI uses different values)

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