[86431] in North American Network Operators' Group
Re: classful routes redux
daemon@ATHENA.MIT.EDU (Russ White)
Fri Nov 4 09:07:52 2005
Date: Fri, 04 Nov 2005 09:07:13 -0500
From: Russ White <riw@cisco.com>
To: "Stephen J. Wilcox" <steve@telecomplete.co.uk>
Cc: Richard A Steenbergen <ras@e-gerbil.net>,
Todd Vierling <tv@duh.org>, Fred Baker <fred@cisco.com>,
Bill Woodcock <woody@pch.net>, bmanning@vacation.karoshi.com,
nanog@merit.edu
In-Reply-To: <Pine.LNX.4.44.0511032113050.25860-100000@server2.tcw.telecomplete.net>
Errors-To: owner-nanog@merit.edu
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>>>A routing table capable of handling a flat 2^128 addressing space goes
>>>beyond the realm of known physics -- and flat 2^64 comes close, at least for
>>>a while (consider semiconductor atomic weights, and the fact that 1 mole is
>>>approximately 2^79 atoms). That's quite a stretch, but should give a hint
>>>as to why flat addressing does not work for every model.
>>
>>Come on now, a lot of new routing gear made today can just barely handle
>>2^18 routes, and even the high end stuff tops out at 2^20. We're nowhere
>>near handling 2^32 routes even for IPv4, nor should we be, so lets not
>>start the whole "but ipv6 has more space therefore routes will increase to
>>7873289439872361837492837493874982347932847329874293874" nonsense again.
>>Removing the extreme restrictions on IP space allocation by being able to
>>allocate chunks so large that you would RARELY need to go back for a
>>second block would immediate reduce the size of the routing table. Let me
>>state the stats again for the record:
>>
>>Total ASes present in the Internet Routing Table: 20761
>>Origin-only ASes present in the Internet Routing Table: 18044
>>Origin ASes announcing only one prefix: 8555
>>Transit ASes present in the Internet Routing Table: 2717
>>
>>There are just not that many distinct BGP speaking networks out there, nor
>>will there ever be. NOW is the time to make certain that IPv6 deployments
>>makes sense in practice and not just in theory, so we don't work ourselves
>>into exactly the same mess that we did in IPv4. Lets stop trying to solve
>>theoretical scaling problems which will never happen at the expense of
>>creating problems which actually DO exist, and apply a little bit of common
>>sense.
> whilst i'm at the mic here, ditch the idea of microassignments, just give out a
> standard /32 block ... lets not start out with ge 33 prefixes in the table when
> theres no need
Hmmm.... Some interesting points:
- -- 2^32 is still larger than 2^20, which is claimed to be the largest
feasible size, above.
- -- BGP is currently moving to a 2^32 space for AS numbers. That's odd,
if there's only 18,044 origins in the current table, and it won't ever
grow to much more--how'd we lose 40,000 or so AS numbers, that we now
need more than 64,000?
Just curious.
:-)
Russ
- --
riw@cisco.com CCIE <>< Grace Alone
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