software routers (was: Cogent service)

Sat Sep 21 10:06:56 UTC 2002

On Fri, 20 Sep 2002, Stephen Sprunk wrote:

> If you think you can make a gigabit router with PC parts, feel free.

You may be surprised to learn that BBN folks did practically that
(different CPU) with their 50 Gbps box (MGR). They had OC-48C line cards
and used Alpha 21164 CPU with pretty small 8Kb/94Kb on-chip cache to do
packet forwarding.

See C.Partridge et al in IEEE/ACM Transactions on Networking, 
6(3):237-248, June 1998.

The CPUs are quite faster nowadays, and you can get things like _quad_ 
300MHz PPC core on an FPGA plus 20+ 3.2Gbps serdes I/Os - all on one chip.
So building multigigabit software router is a no-brainer.

(16-4-4-4-4 was in Pluris proof-of-concept; the smaller branching factor 
in the radix tree was to get a better match to Pentium's L-1 cache line 
size, and to make prefix insertion/deletion faster).

--vadim

PS.  We were talking _mid_ 90s.  Back then SSE did about 110kpps (not 
     advertised 250kpps) in the real life, and 166MHz Pentiums 
     were quite available at Fry's.

PPS. I had exactly that argument with ex-cisco hardware folks who came to 
     Pluris; they prevailed, and fat gobs of luck it brought them.  They 
     ended up building a box with exactly the same fabric and comparable
     mechanical and power dissipation parameters as the concept I drew as 
     a starting point in 98.  Wasted time (and $260M) on developing these 
     silly ASICs when CPUs and some FPGAs could do just as nicely. I'm 
     glad that I wasn't around to participate in that folly.