Subject: Re: [RRG] Renumbering... mapping

From: Brian E Carpenter <[email-masked]>
Date: Fri, 22 Aug 2008 09:36:53 +1200

On 2008-08-21 20:16, Iljitsch van Beijnum wrote:
> On 20 aug 2008, at 18:45, Scott Brim wrote:
> 
>> Identifiers are
>> primarily useful for multipath management and session continuity.
>> Identifiers may be in the network layer, and carried in network layer
>> packet headers, for convenience of the endpoints, but that doesn't
>> mean they should be included in routing information.
> 
> Well, then the question is: do we look up locators based on these
> identifiers?
> 
> If no, then they purely function on the transport and higher layers and
> have no relationship to the network layer so they might as well not
> exist for our purposes.
> 
> If yes, they need to have some hierarchy or have a very low granularity
> so their total number remains low in order to make the lookup function
> scale.

Is there any reason that we can't use the Paul Francis/CRIO style of
virtual aggregation in a mapping system? That would be easier to
understand and describe than a DHT, but would deal reasonably well
with the granularity issue. There are also some interesting ideas
in SiMIA that might move across to a mapping system.

On 2008-08-22 03:01, Eliot Lear wrote:

> Yakov Rekhter wrote:
>> I'd like to pose the following two questions:
>>
>> 1. Do folks agree that to get to the point where 2^48 PI spaces
>> would become a reality is likely to require *massive* deployment of
>> v6-to-v4 NAT ?
>>    
> 
> No.  And there is a solution on the table that demonstrates this.

Well, that does depend on the real scalability of the mapping system
if the PI/EID space is highly fragmented. See above.

> 
> [And while the answer would remain the same, 2^48 PI spaces seems just a bit  large.  Not necessarily a bad thing, mind you.  The population of the earth is 2^33.] 

It does, but 2^33 prefixes sparsely arranged in a 2^48 space is
an issue. See above. However, would a lower estimate, say 2^23
(8 million) prefixes be an issue? If not, why can't we start on the
assumption that we know how to support a map with 8 or 10 million
entries, and have many years to figure out a sparse mapping system
with several orders of magnitude more entries?

    Brian

--
to unsubscribe send a message to [email-masked] with the
word 'unsubscribe' in a single line as the message text body.
archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg