Implementations/suggestions for Multihoming IPv6 for DSL sites

Owen DeLong owen at delong.com
Mon Apr 11 08:37:41 CDT 2011


On Apr 11, 2011, at 6:30 AM, Luigi Iannone wrote:

> 
> On 11, Apr, 2011, at 15:17 , Owen DeLong wrote:
> 
> [snip]
>>>> 
>>>> Doing IPv4 LISP on any kind of scale requires significant additional prefixes which at this time doesn't seem so practical to me.
>>> 
>>> This is not accurate IMO. To inject prefixes in the BGP is needed only to make non-LISP sites talk to LISP sites. Even there you can aggressively aggregate, as explained in draft-ietf-lisp-interworking.
>>> 
>>> As long as the LISP deployment progress you can even withdraw some prefixes from the BGP infrastructure and advertise only a larger aggregate in order for legacy site to reach the new LISP site.
>>> 
>>> Luigi
>>> 
>> Who said anything about BGP? I was talking about the amount of additional IP space needed vs. the
>> amount of IPv4 free space remaining.
>> 
> 
> Sorry. I misunderstood. 
> 
> But can you explain better? Why should LISP require more IP space than normal IPv4 deployment?
> 
> If you are a new site, you ask for an IP block. This is independent from whether or not you will use LISP.
> 
Sure, but, if you also need locators, don't you need additional IP space to use for locators?

> If you are an existing site and you want to switch to LISP why you need more space? you can re-use what you have?
> 
Perhaps I misunderstand LISP, but, I though you needed space to use for locators and space
to use for IDs if you are an independently routed multi-homed site.

If you are not an independently routed multi-homed site, then, don't you need a set of host IDs
to go with each of your upstream locators?

As I understand LISP, it's basically a dynamic tunneling system where you have two discrete,
but non-overlapping address spaces, one inside the tunnels and one outside.

If that's the case, then, I believe it leads to at least some amount of duplicate consumption of
IP numbers.

> Or I missed the point again?
> 
Or perhaps the complexity of LISP in the details still confuses me, despite people's insistence
that it is not complex.

Owen

> thanks 
> 
> Luigi
> 
> 
> 
>> Owen
>> 
> 




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