Robin,
Thanks for explaining your reasoning:The problem is that if the mapping system is required to map each host identifier onto a (set of) locators, then I don't see how one can build a stable and scalable mapping system.with which I disagree entirely. Just because the mapping system is capable of specifying mapping for a single IP address doesn't mean it is required to be able to do it for every IP address in the system.
In the wordings that I used, I do not prohibit the mapping system from being able to specify a mapping for each host identifier.
"The identifier to locator mapping function MUST support mapping entries for aggregates of identifiers. It MAY also support mapping entries for host identifiers."
The first sentence means that the mapping function must be designed with aggregates in mind and must deal with aggregates (the larger the better from a scalability viewpoint). Then, the second sentence means that some parts of the mapping may choose to provide more specific mappings, but an entity that requested a mapping shall not be obliged to accept a mapping reply which is more specific than its request. It may accept such a more specific reply if it wishes to do so.
So there is no scaling problem with having the mapping system work with the location of boundaries between one EID prefixes / micronet and the next definable in units of single IP addresses. Maybe the final IPv4 mapping system will be able to handle 4 billion micronets, or maybe it can only handle a billion. A consumer terabyte hard drive could store 250 bytes of mapping for every single IPv4 address - so I don't see that storage is a problem.
I don't believe that the mapping system will be placed on a consummer terabyte hard drive... The main concern with using host identifiers from a scalability viewpoint is the potential churn, not the amount of storage.
Olivier -- http://inl.info.ucl.ac.be , Universite catholique de Louvain, Belgium -- to unsubscribe send a message to rrg-request@psg.com 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