[AusNOG] Going Dual Homed (without waste)

[Tom Berryman]

Planning to "balance" your load over 2 BGP paths is a naïve way to start this project. You cannot control the way other networks choose to route to you, you can only control your own routing. 

If you were to buy a total of 600mbit from 2 providers, you should look at your traffic profile and do some research on potential providers and look at the BGP path selection of other networks (where you source traffic from) to each potential provider. Your results will only be an estimate though.

What will likely happen is you will look at 300 from provider 1 and 400 from provider 2 - I would consider this pretty good "balancing" (load sharing really) and you will have a little extra on each provider.
Obviously this also reduces the impact of a transit provider failure.

Another alternative is to look at providers who offer bursting (I have just seen Greg beat me to this I think) - You may buy 300 from 2 providers, with a bursting feature - pay for 300 and get to use 500 for example. But consider with this, when over your committed 300 you will be charged extra.

Tom

-----Original Message-----
From: AusNOG [mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of James Mcintosh
Sent: Thursday, 26 September 2013 5:53 PM
To: ausnog at lists.ausnog.net
Subject: [AusNOG] Going Dual Homed (without waste)

Hi Noggers,

Somewhat of a follow on from my previous post. I got a lot of comments back saying we should be muti-homed rather than single homed as we currently are.

I agree, however my question is how do we do so without over-provisioning transit and having too much "waste". If we're currently pumping around 600Mbps of inbound traffic through a single transit provider, how would we equally balance that across two transit providers at 300Mbs each.

Sure we could advertise some of our IP blocks via transit provider A and other IP blocks via transit provider B but that is hardly my idea of an easy load balancing solution and the traffic levels could still vary dramatically depending on downstream activities.

Your comments and ideas are much appreciated.


-James

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