Non-goals: No guarantees of unique address allocation-not possible (with meeting other constraints, and not necessary)
Draft made the I-D deadline.
Low probability of collision.
Adapt to long-term changes in topology (i.e. days)
Avoid third-party dependencies.
BGP was going to be used to distribute group range information, but BGP doesn't have all that is needed.
MASC devices claim a range that gets advertised to all via MASC peerings. It waits to hear if there are any conflicts for a set period of time. If no conflicts, then they get advertised via BGP.
The top-level consists of several sibling BGP peers in the current model. This generated a lot of discussion, since people were unclear how the top-level allocation will shake out from this, and were generally uncomfortable with the fuzziness level here. This is a big open issue.
Overallocation is penalized because by overallocating, one agrees to become the root router for that whole new "domain".
MASC is not tied to BGP or BGMP, but will prbably be in practice. Usually, BGP and BGMP will be expected at borders of the AS. There may be multiple multicast ASs within a single unicast AS.
Claim-collide was chosen to avoid single root allocator.
Group addresses have finite lifetimes, and expire if not defended.
Open issue: contiguous vs. non-contiguous masks for suballocation.
Pavlin from USC/ISI is running the simulations, and the initial results were presented. More on the website at http://netweb.usc.edu/pavlin/masc-results/.
Near 100% utilization of addresses within a domain block.
"Domain" will typically be an AS. If a unicast AS is too large, it can be split into multiple multicast AS's and BGMP run at the border.
The implementation of this is that a MAAS server must warm up a fixed period of time (e.g. 5 minutes) before ever allocating an address. After that time, the server chooses a random provisional announcement, waits for a collision, and if there's no problem, it claims and defends that address.
A MAAS server can preallocate address by allocating them before receiving a request.
Addresses can be deleted as an optimization. Since everything expires, this isn't a necessary feature, but probably desireable.
MAAS servers send periodic ADDRESS-SPACE-REQUIRED messages reporting current or desired address space requrements to MASC servers.
More information about all of this stuff can be found at the malloc web site at http://north.east.isi.edu/malloc/.