Re: Policy-based routing is evil? Discuss.

[Jeff Kell <jeff-kell () utc edu>]

As others have pointed out, PBR ...

* Is a fragile configuration.  You're typically forcing next-hop without
a [direct] failover option,
* Often incurs a penalty (hardware cycles, conflicting feature sets, or
outright punting to software),
* Doesn't naturally load-balance (you pick the source ranges you route
where)

However, there are few alternatives in some cases...

* If you are using some provider-owned IP space you often must route to
that provider,
* There may be policies restricting what traffic (sources) can transit a
given provider

There are few alternatives for the latter cases, unless you split the
border across VRFs and assign routing policy on the VRF, which is a
global decision across the VRF, and avoids PBR.

We're doing a little of both, so I clearly don't take sides :)

Jeff

Attachment: signature.asc
Description: OpenPGP digital signature