Failover how much complexity will it add?

Joel Jaeggli joelja at
Fri Nov 13 01:40:51 UTC 2009

Randy Bush wrote:
>> It has been routinely observed in nanog presentations that settlement
>> free providers by their nature miss a few prefixes that well connected
>> transit purchasing ISPs carry.
> just trying to understand what you mean,
>   o no transit-free provider actually has all (covering) prefixes needed
>     to cover the active space, but
>   o one or more reasonably small subsets of the set of transit-free
>     providers do cover the whole active space.

If your goal is near-complete coverage, under normal circumstances you
need more than one (your subset). Settlement-free provider peering spats
are a degenerate condition of the normal state of affairs. The
non-settlement-free provider has some subset already.

Pointing default into a settlement-free provider, that is deliberately
not speaking to another is obviously a recipe to lose data, which speaks
to the question of whether one should as for a full table from
settlement free upstreams.

My somewhat obtuse point was that this isn't some wild west frontier
justice sort of affair, but rather, the normal state of affairs.

> randy

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