nanog mailing list archives

Re: Vyatta as a BRAS


From: Mikael Abrahamsson <swmike () swm pp se>
Date: Wed, 14 Jul 2010 08:34:45 +0200 (CEST)

On Tue, 13 Jul 2010, Lamar Owen wrote:

Instruction issue? Execution unit? Special instructions? Sounds like a software-driven processor to me. Specialized software instruction set, yes. True hardware forwarding, no software involvement? No. More like asymmetrical multiprocessing software routing. Call it hardware accelerated if you like; PXF is to networking as a nVidia GeForce GPU is to graphics.

This is true on a lot of newer Cisco high end platforms. CRS-1 uses multicore processors (hundreds of cores) for forwarding on their linecards, and they achieve 40+ Mpps per linecard.

This is the trend in networking where you need to do intelligent things, it's easier to do multicore parallell processing than doing hugely fast FPGA forwarding (at least it seems that way, and it's faster to upgrade the software on a CPU than on a FPGA).

The lines are blurring between CPU/FPA/ASIC (well, ASIC is really a misnomer as it's just "application specific" which means packaging, not function) and since people want flexibility, general CPUs used for forwarding is the way it's headed, even though the CPUs right now have little to do with the CPUs we see in "normal" PCs.

--
Mikael Abrahamsson    email: swmike () swm pp se


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