Forwarding is in line cards not because of CPU issues, but because of BUS issues. It means, that card can be software based easily.
Anyway, as I said - it is only small, minor engineering question - how to forward having 2,000,000 routes. If internet will require such router - it will be crearted easily. Today we eed 160,000 routes - and it works (line cards,m software, etc - it DO WORK). ----- Original Message ----- From: "Lincoln Dale" <[EMAIL PROTECTED]> To: "Alexei Roudnev" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]>; "Daniel Senie" <[EMAIL PROTECTED]> Sent: Wednesday, October 26, 2005 2:42 AM Subject: Re: Scalability issues in the Internet routing system > > Alexei Roudnev wrote: > > You do not need to forward 100% packets on line card rate; forwarding 95% > > packets on card rate and have other processing (with possible delays) thru > > central CPU can work good enough.. > > heh. > in the words of Randy, "i encourage my competitors to build a router > this way". > > reality is that any "big, fast" router is forwarding in hardware - > typically an ASIC or some form of programmable processor. > the lines here are getting blurry again .. Moore's Law means that > packet-forwarding can pretty much be back "in software" in something > which almost resembles a general-purpose processor - or maybe more than > a few of them working in parallel (ref: > <http://www-03.ibm.com/chips/news/2004/0609_cisco.html>). > > if you've built something to be 'big' and 'fast' its likely that you're > also forwarding in some kind of 'distributed' manner (as opposed to > 'centralized'). > > as such - if you're building forwarding hardware capable of (say) 25M > PPS and line-rate is 30M PPS, it generally isn't that much of a jump to > build it for 30M PPS instead. > > i don't disagree that interfaces / backbones / networks are getting > faster - but i don't think its yet a case of "Moore's law" becoming a > problem - all that happens is one architects a system far more modular > than before - e.g. ingress forwarding separate from egress forwarding. > > likewise, "FIB table growth" isn't yet a problem either - generally that > just means "put in more SRAM" or "put in more TCAM space". > > IPv6 may change the equations around .. but we'll see .. > > > cheers, > > lincoln.
