Software-based Border Router

Michael DeMan nanog at deman.com
Mon Sep 27 22:02:30 CDT 2010


I have seen software based routers (FreeBSD+Quagga) in production at pennies on the dollar compared to Cisco for quite some years.

Up front, as other people have noted, you need to know what you are doing.  There is no 'crying for help 24x7'.  By the same token, if you know what you are doing then they can be a very cost effective solutions.

I have yet to see (or try out) MPLS and such, so if requirements need features like that, then probably open source may not be the solution.

The above said, other comments inline below...


On Sep 27, 2010, at 3:48 PM, Heath Jones wrote:

> Do jitter sensitive applications have problems at all running?
> What would you say is the point at which people should be looking for
> a hardware forwarding solution?
> 
> Differences:
> - Hardware forwarding

Yes, absolutely, no hardware forwarding.  This must be compensated for by utilizing as advanced/expensive 'commodity PC hardware' as possible.  You want lots of CPU horsepower, fast busses (PCI-E x16 if possible) and good NICs so the OS can offload as much as possible to the hardware and not be bandwidth constrained.  Even then, no way are you going to get anything close to what you can from a 'real' router.  A classic trade off between technical needs & desires vs. financial constraints.  

> - Interface options

Make sure there are least two NIC platforms.  i.e., a pair of onboard dual gigabit plus another dual gigabit card.  Bond the interfaces between the separate NIC platforms so one each gigabit link is off say the onboard and one off the NIC card.  Utilize LACP.

> - Port density

Use VLANs - again, a quality NIC will help with this by offloading a good portion of the overhead to hardware.

> - Redundancy

Use a /29 to your eBGP provider and turn up two routers side-by-side.  Again, if you are looking for hard core 'carrier grade' stuff, you should not be asking about open source.  Pair the two routers, for eBGP sessions, and use a separate interface for them to talk to each other.

> - Power consumption

Always an issue, no way are you going to get pps from this kind of stuff like you would from Cisco.

> - Service Provider stuff - MPLS TE? VPLS? VRF??

Yup.

> 
> Any others?
> 

If somebody is on an extremely tight budget, is technically capable of doing utilizing open source to do what they need, and their requirements are limited enough that an open source platform would work for them, I would suggest they check into it.  Ultimately, as always, it is buyer beware.  Often with dedicated routers a support contract can cost as much as the router itself after a year or two, but sometimes companies need that support contract because they don't have the in-house skills already, etc.  

I would never recommend either open source or dedicated hardware routers to anybody as a 'this is the only way to go' solution.





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