Re: Linux based router for Gigabit traffic

[Neil Horman <nhorman@redhat.com>]

Anantha Kiran wrote:

>Hi
>I am doing a project, in which i have to redirect traffic coming from
>one ethernet card of a machine, to one of three remaining three
>ethernet cards of same machine based on the src,dest IP and Port
>values of the pkt. I wrote a net_hook module to do this which i
>working fine for lower speeds like < 400 Mbps traffic. But project
>goal is to deal with gigabit traffic. I have used gigabit ethernet
>cards and Switch. But when the traffic rate is more than 400Mbps it is
>dropping packets.  I did test, by increasing the transmit queue
>length. But same problem is coming. I have found during the pkt drop
>there is no memory or CPU is hundred percently utilised. So, what can
>be the resource that is lacking while dropping of pkts is happend.
>
>We have done a test, in which module will simply forward pkts from
>"eth0" through "eth1". Same problem of pkt dropping at highier speed
>is happening.
>
>Now we thought , it can be due to PCI bus. But we are unable to find
>what is configuration of PCI bus , our system is using. we have used
>"lspci" to find that. But i am unable to interpret it. I am attaching
>that output file. Can anybody tell me how to interpret that or give
>some guidelines , like whom to mail, to find that.
>
>Atlast we try to solve the problem in the following manner. Idea is
>to, install a router for my machine which can deal with gigabit
>traffic. If the router is able to work with gigabit traffic, then
>definitely pkts dropping will not be due to PCI bus.
>
> So, canbdoy please, suggest some  opensource router for linux which
>can deal with gigabit traffic. Or atleast some suggestions to solve
>this problem.
>  
>
Quite simply a general purpose CPU system isn't  normally built to 
handle network traffic at gigabit rates, especially not from multiple 
ports at once.  If you really want a line rate gigabit router, you need 
custom ASIC to do hardware offload of that work.  Several networking 
companies make just such hardware (of course most only sell the chips, 
not full pci cards with integrated NICS).  Check out broadcom, AMCC or 
Intel, they all have hardware like what you're looking for.
Neil