Re: hardware vs software

On 2011-10-12 22:20, imran ali wrote:
> hi all ,
>
> Hardware vs software
>
> what exactly ment by hardware or software processing

When the router forwarding plane is based on the ASIC/FPGA, it's
called 'hardware router', when it's only CPU to do all the work,
be it Intel or Motorola or whatever - it's 'software router'.

The edges are blurry in terms of what's hardware and what's
software processing, but you can say safely, that platforms like
Cisco 12000, ASR 9000 or CRS-1/3 are hardware routers. The software
routers are all access ISRs - like 8xx/18xx/19xx/28xx/29xx/38xx/39xx or
even 7200 with NPEs.

Hardware forwarding is also part of the QFP processor, the unit
powering up the ASR 1000. This 'hardware' however is more generalized
than the ASICs present on the GSRs or CRSes, and it's in fact a matrix
of CPUs programmed dynamically to perform some specific functions.
But the way QFP is organized gives an impression that's in fact a
"hardware processing". It's similar in concept to the PXF processors
used in the NSE series of RPs on 7300, uBRs and some time ago on 7200.

There are more subtleties - like for example, NPUs present on the
ASR 9k or ES+ cards for 7600. Those are microcode-driven ASICs, that
are reprogrammed during the life of the unit according to the
configuration. But in general, those are called 'hardware routers'.

-- 
"There's no sense in being precise when |               #ukasz Bromirski
  you don't know what you're talking     |      jid:lbromirski_at_jabber.org
  about."               John von Neumann |    http://lukasz.bromirski.net
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