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Re: Aggregation Implies Provider Dependence // Re: [RRG] ALT's strong aggregation often leads to *very* long paths
Eliot -
First of all, I could easily imagine partnerships forming between ALT
providers that share portions of the address space and allow their
customers to renumber from one partner to another. This isn't pure
independence, but it is something.
The question is whether ALT operators would be willing to engage in such
a cooperation with their competitors. They could do the very same thing
already today in order to make renumbering a less frequent event without
sacrificing routing scalability. But they are NOT doing it -- which is
why we are looking for alternative solutions here in RRG...
Second, the degenerate scenario that you describe is that we are fully
disaggregated. That means that there is a lot of STATE. It says
nothing about RATE. This will depend very much on how the LAT is
managed. If the LAT is extended to the last mile link without any
static announcements, we would have precisely what we have today.
However, if LAT announcements are relatively static, then the question
is this: who cares?
I am assuming that you are suggesting the following. Please clarify if
I understood you incorrectly:
- Relax the requirement for aggregation in the LAT.
- The cost of such disaggregation will be a larger LAT routing table.
But since the LAT won't be used for traffic engineering purposes (as
BGP is in today's single Internet topology), the update rate of the
LAT routing table won't necessarily go up.
This is certainly a valid observation.
I believe the important point here is that there is a trade-off between
aggregation within the LAT and provider-independence of EID space. The
compromise affected by the ALT specification is in favor of aggregation
-- and as I have said in my previous email, this makes EID space
provider-dependent. Your suggestion above affects a compromise in favor
of provider-independence -- at the cost of larger LAT routing tables.
Both compromises have their pros and cons. Important is that we are
aware that we would have to make this trade-off if we went for ALT.
- Christian
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