[c-nsp] IPV6 in general was Re: Large networks

[Phil Mayers]

Grzegorz Janoszka wrote:
> Phil Mayers wrote:
>> Grzegorz Janoszka wrote:
>>> Daniel Verlouw wrote:
>>>> No real experience with HSRP though, can anyone shed some light on that?
>>>> I understand it only works for link-local addresses?
>>> Yes, unfortunately it is only link-local. I am just trying to figure 
>>> it out how to marry link-local with our global ipv6 assignments.
>> That's now the way it works AFAICT.
>>
>> Basically, the routers still send router-advertisments. However, the 
>> link-local address in the next-hop is the HSRPv6 virtual IP, and floats 
>> between the active & backup.
>>
>> So you only *need* the link-local.
> 
> But it is strange indeed. We tell everyone that v6 is just the same as 
> v4, but just the issues as above makes our customers scary.

It is odd, and takes some getting used to.

> 
> So, we assign 2001:0db8:85a3:08d3::/64 on a customer port, with a 
> gateway fe80:0db8:85a3:08d3::1 - how does it look? Is it the same as we 
> do with v4? :)

Well, no ;o)

TBH the link-local is one of the things that IPv6 did really make a good 
choice on (killing fragmentation is another)

It looks even weirder if you run an OSPFv3 network with nothing but 
loopbacks & link-local - kind of like "ip unnumbered" everywhere!

> 
> Do you have any plans for such IP division? I just thought about 
> replacing first 16 bits of public v6 address with fe80, but maybe you 
> have better ideas.
> 

I don't understand; all link-local IPs are

fe80::/64

i.e. link-local are always fe80:0000:0000:0000:<the mac>

You can't change this I think.