[j-nsp] Generating routes from inactive/hidden contributors

[adamv0025 at netconsultings.com]

> Tore Anderson
> Sent: Friday, March 03, 2017 11:33 AM
> 
> Hi,
> 
> I'm looking to generate a route, and do so even if the contributing routes
are
> inactive or hidden.
> 
> The use case is to receive a full feed from an upstream provider and
> generate a default route pointing to that provider IFF I've received at
least
> one route from them that proves that they are in turn receiving routes
from
> their upstream(s). The point of having this generated default route is of
> course to be able to optimise away all the (now
> redundant) contributing routes.
> 
> I've tried the following as a proof of concept:
> 
> set routing-options rib inet.0 generate route 1.1.0.0/19 policy testpol
set
> policy-options policy-statement testpol term 1 from as-path teliatest set
> policy-options policy-statement testpol term 1 then accept set
policy-options
> policy-statement testpol term 2 then reject set policy-options as-path
> teliatest .*1299.*
> 
> While I do have contributing routes within 1.1.0.0/19 matching the
as-path,
> they are all inactive, and thus the generated route does not go active
either.
> Furthermore, it makes no difference to add:
> 
> set policy-options policy-statement testpol term 1 from state inactive
> 
> I also get the same results if I filter out the contributing routes in my
> upstream's import policy (i.e., making them hidden rather than inactive).
> 
> Anyone know of a clever trick to get the behaviour I'd like?
> 

Interesting, 
There appears to be no cmd to override the default, "contributing route has
to be active", requirement. (the "from state inactive" attachment point is
only the export policy). 
I'm just thinking whether it's not working simply because the inactive
routes wouldn't be advertised anyways -so why to bother aggregating them
right? 
But maybe if you enable "advertise-inactive" towards your iBGP -maybe then
the aggregation starts to work? 

Alternatively, I'm thinking of something along the lines of making the
prefixes active (to allow the aggregate to be advertised), but use them only
for routing not for forwarding -so that FIB on a local router is not skewed.

 


adam


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