IPv6 beginner's config questions

[CriscoSystems]

I am sighing in desparation about my upcoming BSCI exam...anyhow:

On my 2501's that have IOS 12.3(24) installed, I'm trying to get OSPFv3 running. At the (config)# prompt I type "ipv6 router ospf 100" but I just get another (config)# prompt, rather than going into router configuration mode. Whereas if I type "ipv6 router rip myroutes" I get a (config-rtr)# prompt. Should I be worried about the OSPF side?

Question #2: I read that an interface can have a global aggr. unicast address, one or more link-local addresses, and one or more anycast addresses. Anycast addresses come from the same address space as global unicasts, but the router needs to know that the address is an anycast address - what command or keyword do you use to let the router know this?

THanks,

stuey

[Reza Sharifi · Accepted solution]

stuey,

I did a quick search using the future navigator for IPv6 Routing: OSPF for IPv6 (OSPFv3)on 2500 series, but had no luck. I can see the 2600s (even 2610) in the list but not 2500s.

HTH

Reza

[CriscoSystems]

Actually I found something at

http://www.cisco.com/en/US/docs/ios/ipv6/command/reference/ipv6_05.html#wp2165859

however, the "anycast" keyword is not recognized on my 2501!! I will have to hope this doesn't hold me up too much on the BSCI.

[Giuseppe Larosa]

Hello Stuey,

>> Question #2: I read that an interface can have a global aggr. unicast address, one or more link-local addresses, and one or more anycast addresses.

I think only one link local address, one or more global addresses , one or more unique local addresses per interface

anycast is more a concept and it is not widely used.

Hope to help

Giuseppe

[CriscoSystems]

One link local and "one or more unique local addresses..." is there a difference between link-local and unique local?

anycast may not be widely used, but it sure seems to be in the BSCI curriculum.

I would like to see IPv6 outlawed.

[Giuseppe Larosa]

Hello Stuey,

>> One link local and "one or more unique local addresses..." is there a difference between link-local and unique local?

yes there is a big difference:

link local is not routable because it is always the same ipv6 prefix FE80.

unique local are routable: a different IPv6 prefix per link is deployed and they are similar to RFC1918 private ip addresses.

fc00/7 see

rfc4193

about anycast:

the anycast concept is present also in IPv4 but it doesn't have a formal definition: anycast RP or some designs that for redundancy use same ip addresses and route to the nearest one.

an anycast address represents a service and a packet destined to an anycast address is forwarded to the nearest device offering that service.

Hope to help

Giuseppe