Why IPv4 address in EIGRPv6 and other that type protocol?

tomislav91

Is there some theory why is that ?
Why is IPv4 in EIGRPv6???

Jon_Cisco

Can you give us an example of what you are trying to understand?

fredrikjj

Typically in the IPv6 routing protocols they've reused most of the packet format with the result that you need a 32 bit address to fill the router id field and stuff like that. In practice this means that you need to either configure an IPv4 loopback address or manually set the router id even in a pure IPv6 environment.

Is that what you are asking?

tomislav91

I mean, if we configure eigrpv6, we must configure router-id manually. Example 1.1.1.1, why not usign 10:10:10:10, why ipv4?
It is because that ipv4 is sufficent, there is no network with a billion routers Or have some theory why ipv4 in ipv6 protocol?

networker050184

The router ID is just a 32 bit identifier of the router. It is formatted like an IPv4 address, but is not used for forwarding.

tomislav91

But why is IPv4 when using IPv6 networking?

networker050184

It's not necessarily an IPv4 address. Just a 32 bit identefier in dotted decimal format. The logic behind this is most routers are going to have a loopback with an IPv4 address assigned anyway.

Heero

It is similar to how IS-IS still uses OSI NSAP addresses for router identifiers. It's just a holdover from the IPv4 version of EIGRP. They decided to change as little as possible. The router ID in EIGRP is NOT an IP address. It has the same format and can be sourced from a locally configured IP, but the actual identifier is just a number. If you had no IPv4 configured at all on the router, you would just manually enter the router ID for the box to use.