[127781] in North American Network Operators' Group
Re: Vyatta as a BRAS
daemon@ATHENA.MIT.EDU (Valdis.Kletnieks@vt.edu)
Wed Jul 14 08:02:39 2010
To: "Dobbins, Roland" <rdobbins@arbor.net>
In-Reply-To: Your message of "Wed, 14 Jul 2010 02:18:18 -0000."
<C08DFC85-6BBD-4A27-82DD-BCFBA99136E5@arbor.net>
From: Valdis.Kletnieks@vt.edu
Date: Wed, 14 Jul 2010 08:01:56 -0400
Cc: NANOG list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
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On Wed, 14 Jul 2010 02:18:18 -0000, "Dobbins, Roland" said:
> Right. And to date, such routers make use of ASICs - i.e., 'hardware-based'
> routers, in the vernacular.
>
> Routers which use only centralized, general-purpose processors can't handle
> even a fraction of 'line-rate' without tanking
But as others have stated, the 7206 has at least some hardware acceleration,
so it's *not* a router that uses *only* centralized general-purpose CPUs. So
at least some hardware-assisted routers tank under loads too.
And even the most heavily hardware-assisted systems have to do call outs from
the FPGA's for *some* stuff, and can be tanked by suitably creative abuse of
their weaknesses. Of course, in general the more hardware assist, the harder
it is to tank (but it's never impossible).
So basically, your definition of "hardware based" router is "one that has enough
FPGAs to not tank under some arbitrary workload". Not very useful,that.
Let's face it Roland - it's a continuum from hardware to software, and in many
places it's downright murky which it is. Is the CRS-1 hardware or software?
Lots of custom hardware in there - but lots of processing cores that look
suspiciously like software engines too.
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