[138683] in North American Network Operators' Group
Re: estimation of number of DFZ IPv4 routes at peak in the future
daemon@ATHENA.MIT.EDU (Joel Jaeggli)
Sat Mar 12 02:16:31 2011
In-Reply-To: <845E1195-46D2-4DB9-926F-8AEF4D833BB7@delong.com>
From: Joel Jaeggli <joelja@bogus.com>
Date: Fri, 11 Mar 2011 23:17:19 -0800
To: Owen DeLong <owen@delong.com>
Cc: "nanog@nanog.org" <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
I'm super-tired of the "but tcams are an expensive non-commodity part not su=
bject to economies of scale". this has been repeated ad nauseam since the ra=
ws workshop if not before.
You don't have to build a lookup engine around a tcam and in fact you can us=
e less power doing so even though you need more silicon to achieve increased=
parallelism.
RFC 4984 has a lot of useful insights in it but it was flat wrong about two t=
hings since 2007. The impact of rate of growth in the DFZ(for one thing chur=
n failed to grow in lockstep), and the ability of the technology to keep up.=
Not all the devices in your network need a 2 million route FIB, yet getting a=
device today that has one isn't that hard. and it'll be a lot easier in fiv=
e years and it likely will do so without having a 144Mbit CAM ASIC.
I don't know if we'll be using commercially viable MRAM implementations in p=
lace of SRAM cells in a decade or if we'll have more of the same only smalle=
r and faster and much much wider, Or if the LISP religion will take over the=
world and we'll carry the state for diversely connected edges elsewhere in t=
he stack. What I am confident of is that as an industry we'll be able to del=
iver something that works without jacking up the Internet routing system and=
replacing it, and without somehow altering the individual decision making p=
rocesses in many tens of thousands of autonomous systems. I am also confiden=
t that the early adopters will pay more for the technology than the straggle=
rs, that we will grumble about how much it costs and the inevitability of ob=
solescence, and that life will somehow go on.
Joel's widget number 2
On Mar 11, 2011, at 17:53, Owen DeLong <owen@delong.com> wrote:
>=20
> On Mar 11, 2011, at 5:43 PM, William Herrin wrote:
>=20
>> On Fri, Mar 11, 2011 at 6:39 PM, Justin Krejci <jkrejci@usinternet.com> w=
rote:
>>> On Wed, 2011-03-09 at 09:32 -0500, John Curran wrote:
>>>> On Mar 9, 2011, at 12:43 AM, Majdi S. Abbas wrote:
>>>>> I suspect that as we reach exhaustion, more people will be
>>>>> forced to break space out of their provider's v4 aggregates, and
>>>>> announce them, and an unfiltered DFZ may well approach the 'million'
>>>>> entries some vendors now claim to support.
>>>>=20
>>>> This matches my personal view (and could be viewed as
>>>> "success" compared to the 5M estimate of Mr. Herrin...)
>>>=20
>>> Are people going to be relying on using default-routing then in the
>>> future if they don't upgrade routers to handle large routing table
>>> growth? Or perhaps forgo dual-stack and have a separate physical IPv6
>>> BGP network from IPv4? Are there any other strategies?
>>=20
>>=20
>> Hi Justin,
>>=20
>> IMHO, the most sensible strategy is to recognize that that cost of a
>> route has been dropping faster than the route count has been rising
>> for the past decade. Then recognize that with today's hardware,
>> building a route processor capable of keeping up with 10M routes
>> instead of 1M routes would cost maybe twice as much... 10M being
>> sufficient to handle the worst case estimates for the final size of
>> the IPv4 table in parallel with any reasonable estimate of the IPv6
>> table in the foreseeable future. Better CPU, more DRAM, bigger TCAM.
>> It could be built today.
>>=20
> But the RP is the easy cheap part. It's the line cards and the
> TCAM/etc. that they use that gets pricey fast.
>=20
>> Finally, get mad at your respective router manufacturers for
>> engineering obsolescence into their product line by declining to give
>> you the option.
>>=20
> The option of $60,000 line cards instead of $30,000 or
> even $25,000 instead of $12,000 does not seem like one
> that most would have found appealing.
>=20
>> But that's just my opinion...
>>=20
> And the above is just mine.
>=20
> Owen
>=20
>=20
>=20
