Verio Decides what parts of the internet to drop

George Herbert gherbert at crl.com
Mon Dec 6 22:51:13 UTC 1999


Austin writes:
>George writes:
>>I am not sure whether the danger in opening up the B space for
>>/17 blocks is particularly bad, but lacking a single consistent
>>policy body with sufficient clue about both the Tier-1 backbone
>>issues and the address allocation issues, it's hard to fault
>>any given ISP for insisting on /16s in B space.
>>
>	Sounds good, but what exactly does that mean? Does any end network
>capable of justifying a /24 then get a routable chunk, thus blowing up the
>tables? What if you could do it based upon traffic generation? That would be
>difficult to verify, and the definition for 'large' amounts of traffic is
>ever changing.
>	So, if we say that a /20 is a sufficiently large amount of space to
>get a routable chunk, then they would be able to get it from ARIN anyway,
>and we're back to square one.
>	In the far term as space becomes scarce we will need to find a solution
>to wasted B space, but that is several years out. Perhaps by that time routers
>will have so much memory and CPU as to make an extra ~4 million possible routes
>negligible.

The danger of /17 blocks in B space is limited to 64*256 more routes 
(16 k more, maximum).  All at once that would be bad, but over time
it would be reasonable.  I would personally, were I setting route
policy at a Tier 1, allow a /17 in B space, but there's no reason
to try and force anyone else to accept that.  As others don't
right now and aren't inclined to, I would dissuade anyone from
trying it as it's either going to be a royal pain or impossible
to get routing for.

Again, this is where not having a single policy body is killing us;
some people get oddball blocks, somehow or another, and are then
screwed on routability.  I am most certainly not going to suggest
radical surgery to the current way of doing it; right now, small
places deserving of multihoming have to work at it, and you have
to be clued enough to not step in a few holes like trying to
portably subdivide a B.  I am not sure that there's any obvious
fix in the nearterm for those problems, which are avoidable.
As long as they're avoidable I think the thing to do is to
leave well enough alone.


-george william herbert
gherbert at crl.com
Disclaimer: I speak for myself only, not my ISP, Cats, wife, or car.





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