11. IPv6 Routing Protocols

IPv6 routing protocols are almost the same as IPv4 except for few changes.

1. RIPng

RIPv2 is termed as RIPng (next generation) in IPv6. It is same as the RIP v2 protocol , i.e, a distance vector protocol, has a max hop count of 15 and uses split horizon , poison reverse and other loop avoidance mechanisms but the main difference is that it uses UDP port 521.

Another difference is that with RIPng, the router keeps track of next-hop address using link-local address, not a global address.Also it is possible to enable RIPng directly on an interface without going into router configuration mode

2. EIGRPv6

EIGRPv6 works same as EIGRP in IPv4 except that the use of network command is gone, and the network and interface to be advertised must be enabled from interface configuration mode.

3. OSPFv3

The main changes in IPv6 OSPF are

1. The link state records will be identified by a 128-bit field instead of a 32-bit one.
2. The routers in the network will be identified by one of their IPv6 addresses.
3. The network areas will be identified by on the their IPv6 addresses or an address prefix.
4. An integer signifying the number of prefix bits will be used instead of a network mask.

Also another difference is that the interfaces and the networks attached to them are directly configured on the interface in interface configuration mode.

12. Migrating to IPv6

There are three transition strategies available for migration from IPv6 to IPv4.

They are

1. Dual Stacking
2. 6to4 Tunneling and
3. NAT-PT

1. Dual Stacking

This is the most common type of migration strategy This allows a device to have both IPv4 and IPv6 protocol stack running so that it is capable of continuing on with existing communications and simultaneously run newer IPv6 communications.

2. 6to4 Tunneling

6to4 Tunneling approach is useful for carrying IPv6 data over a network that is still IPv4. So this is like creating a tunnel that carries IPv6 traffic across IPv4 network

3. NAT-PT

NAT-PT (NAT Protocol Translation) is usually used as a last resort for migration because it is not a great solution when compared to others.

With this, IPv4 hosts can only communicate with other IPv4 hosts and those that are IPv6 hosts with other IPv6 hosts i.e, with NAT-PT there is no encapsulation- the data of the source packet is removed from one IP type and repackaged as the new destination IP type.

13. References