[afnog] IP transit and Load Balancing

[Mark Tinka]

On 9/Jun/15 18:45, Nishal Goburdhan wrote:
>  
>
> in general having two transit providers is a good thing.  three is
> still ok, but more than that (ie. four and greater) becomes a
> nightmare to deal with, so, you’re already off to a good start, if you
> have just two;  no reason to change that!

This is a good point to note. Too much redundancy can make things difficult.

On the other hand, we, as an example, have a reasonably significant
number of interconnects to transit provider (a lot more than 4), but are
able to continue announcing consistently (without de-aggregating,
prepending, e.t.c.) because we also do a lot of peering at major
exchange points. It also helps that the interconnects to the exchange
points and to the transit providers is always the same minimum or higher.

This can work well if you take the time to carefully choose your transit
providers, and also work hard on peering most of your transit traffic away.

But I do realize that this might not be possible for everyone to do, for
various reasons. If you find yourself in this scenario, then choosing
providers who can offer you BGP communities that allow you to influence
how they treat your traffic will go a long way to ensuring you maximize
both your transit and backbone bandwidth. There a lot of good transit
providers out there that can offer you this capability. And of course,
keep them down to two; three at the most if you must.

Mark.