nanog mailing list archives

Re: Implementations/suggestions for Multihoming IPv6 for DSL sites


From: Luigi Iannone <luigi () net t-labs tu-berlin de>
Date: Tue, 12 Apr 2011 10:52:10 +0200


On 11, Apr, 2011, at 17:26 , Owen DeLong wrote:


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?

No, those are the IP address that you provider gives to your border router.

Right... In addition to my provider independent addresses... That's more address space than is required
if I am not using LISP.


No, you just use the IP addresses of the interface to your upstream as "locators". 
Those addresses are there anyway, right?
So using LISP is not adding anything.



No true. I ask for a PI block that I will use as EID-Prefix, then the locators are part of the address space of my 
providers.
There is no duplication.


Right... Ordinarily, without LISP, I get a PI block and use that for EID and the routing is based on the
EID prefix. With LISP, the EID prefix is PI and I use additional PA resources to do the routing locators.
That's what I meant by duplication. There are additional PA resources required on top of the PI in order
to make LISP work.

I still do not see this duplication (may be I need more coffee this morning..)
You do not need to modify anything in the PA space of your provider. Those resources are there and are used to make 
your block reachable also without LISP. 

Luigi

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