Software router state of the art

Deepak Jain deepak at
Mon Jul 28 19:34:33 UTC 2008

> The problem I'm facing is that if I want something from Cisco that can 
> do at least line-rate T3, I'm looking at least $20k per router. I don't 
> have a uber-budget, so for me, that's kind of painful when I start to 
> need more than one plus spare parts. But, I have a high level of 
> confidence that I can put cards in, some memory, power it up, configure 
> it and I'm good to go.
> Junpier's J-series is a BSD based platform as far as I understand it. 
> ImageStream is *much* more affordable for me, but is Linux-based, and I 
> fear Linux as a router and I don't know what they've done to fix the 
> common gripes with Linux-as-router. I have no idea if either of the two 
> have hardware assist in the cards, but my impression is that they are 
> essentially software platforms with custom interface cards. Interface 
> cards are important to me because I'm operating in an environment where 
> my link to the outside world is probably going to be T1/T3.
> I'm aware of Cisco IOS, then BSD-based and Linux-based platforms that 
> are actually sold as routing products. I also know there are a billion 
> "yay, router!" things out there. T1 cards are easy to find. The only 
> other place I know I could buy a T3 card from is Sangoma. Maybe someone 
> has even used it* T3 card before. Rather than reinvent the wheel alone, 
> nanog has to contain the highest concentration of people that have tried 
> various things and already know what will work and what won't work. I'm 
> not looking for OS politics, just operational experience from people who 
> have access to more money and more hardware than I do to have tried more 
> stuff.
> If my best option is still from the big players, so be it. If there's 
> something else that's just as stable, I want to hear about it. I'm not 
> adverse to some dirty work, but I just don't have the time right now to 
> jump in over my head into a software router project and then fight my 
> way back to the surface. I'm not trying to create something for 
> educational purposes, I need something suitable for a production 
> environment.

[I didn't know what to cut from above, so I left it].

What I've used and seen used before that plays both to the strengths of 
the PC as a router and addresses some of the T3 related issues -- 
especially if you control both ends of the T3.

Using an FE to T3 bridge or FE to T1 bridge as the case may be. With a 
little tuning you can put a rate shaper on the PC (prior art, very 
stable) to not run into off-PC buffering issues. Your PC has plenty of 
cheap buffer. The interface to the comms network is done through a 
dedicated, telco or computer center grade piece of gear.

Everyone here (NANOG) can agree that a 10 or 100Mb/s PC router is a no 
brainer and as long as you aren't using irresponsible gear, this thing 
will route packets forever.

Putting telco interfaces into PCs has always been a little more odd, but 
telco to ethernet bridges are fairly standard and fairly dumb. Depending 
on how many of these you have etc, you can do creative things with 
switches, FR, etc. And cost can be all over the map. I know Pairgain 
used to make good ethernet to T1 bridges, and that's probably the last 
time I remember playing with this stuff.


Deepak Jain

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