Dual Homed BGP

Sun Feb 16 23:03:56 UTC 2020

On 16/Feb/20 18:08, Baldur Norddahl wrote:

>
> From the perspective of someone just starting out being dual homed,
> this will be very different. You are not going to get 7 transits and
> you are not going to be able to peer 85% of the traffic. That is why I
> advocate that it is better to buy transit from a middle tier company.
> Instead of getting a connection to just one so called global carrier,
> you get a package deal with connection to all of them and 85% peering
> one step removed. Plus many of the companies that the middle tier has
> a peering with, is something the tier 1 companies would refuse to peer
> (exception Hurricane Electric).
>
> Also while your company may not need dual connections to each transit,
> the situation is completely different from the perspective of a small
> dual homed customer of yours. That is a lot of paths that are lost if
> this customer where to experience a disruption to the connection to
> your network.
>
> This is especially true if there is an unbalance between the two
> chosen transit providers. Say the other provider is Cogent, which are
> famous for refusing to peer. That means that all those peers, unless
> they have a Cogent contract, they will need to find an indirect path
> to replace your peering.
>
> Of course I may also recommend to simply set your expectations
> modestly. Dual homing will get you redundancy but unless you line up
> all your ducks correctly, you should expect some brownouts in the case
> of a link failure. Simply tell the boss, that unless he wants to pay
> at least double in every way, there will be expected downtime in the
> order of 5 minuttes in the case of a link failure.

Completely agreed, as I highlighted in my post at
https://mailman.nanog.org/pipermail/nanog/2020-February/105953.html as a
response to Adam's original query.

Mark.
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