CNAP/ RegionIDs ?

[Delphine Kaplan <delphine.kaplan@activia.net>]

Reading the draft CNAP we realized there are some unclear definition
about the Region IDs.

We use the acronym "RID" in place of "RegionID".
RIDs are a grouping of areas (an area is a set of IP prefixes)
and are used to link Content and Area ADVERTISE messages.
One objective of RIDs is to reduce the size of messages exchanged
(send only the added prefixes when newly delivered by a content) ,
and to symplify the content management (withdrawing/adding
content on areas identified by RIDs).

our questions are :

1/ how do we know when a RID becomes obsolete ?
- define a TTL for RIDs?
- a RID is obsolete when replaced by a new one? (if TTL=0
    this means RID is no more used),
- explicit withdrawal of RIDs?
- other ideas ?

2/ is the RID list an additive field (wrt Area ADVERTISE messages) ?
for ex. when two CNs are connected to some
identical areas with identical metrics, does it make sense for one of the CN
(non-authoritative for the area) to add its "CNAS:RID" before forwarding
the Area Advertisement further ? In this case we have to put the CNAS in
first part of RID field (similar to BGP community attribute).

3/ what is exactly the notion of "authoritative for a content"
and the notion of "authoritative for an area" ?

4/ are hierarchy of RIDs (meta-RIDs) of some interest ?
in other words should we explicitly handle grouping of RID
(defining a RID which is a set of RIDs is already possible but the
hierarchical relation can not be explicitly stated)


Delphine & Martin