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

[Dragan Jovicic]

>
> I'm looking to generate a route, and do so even if the contributing
> routes are inactive or hidden.
>

I believe "passive" option will keep generate/aggregate route in RIB in the
absence of contrib. routes (with NH discard/reject).
Maybe I misunderstood what you want.

Regard

Dragan

On Sun, Mar 5, 2017 at 4:32 PM, Alexander Arseniev <arseniev at btinternet.com>
wrote:

> They will be - in <whatsthatppername>.inet.0 virtual router, where the BGP
> session terminates.
>
>
>
> On 05/03/2017 14:53, Chuck Anderson wrote:
>
>> Last time I checked the contributing routes have to be in the
>> destination RIB for the aggregate/generate to go active.
>>
>> On Sun, Mar 05, 2017 at 11:26:18AM +0000, Alexander Arseniev wrote:
>>
>>> Hello,
>>>
>>> Have You tried putting all routes from that peer in a routing-instance?
>>>
>>> Then configure aggregate|generate in that instance and leak it into
>>> inet.0|whereever the other peers sit.
>>>
>>> You can leak the whole table from that peer as well, but that
>>> amounts to 2x route memory consumption by that peer.
>>>
>>> HTH
>>>
>>> Thx
>>>
>>> Alex
>>>
>>>
>>> On 03/03/2017 15:07, Tore Anderson wrote:
>>>
>>>> Hi,
>>>>
>>>> * adamv0025 at netconsultings.com
>>>>
>>>> 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?
>>>>>
>>>> True, but this is a generated route, not an aggregated route. They're
>>>> quite similar, but the generated routes can have next-hops (copied from
>>>> a contributing route), which means you don't really need the
>>>> contributing routes themselves to be active or even non-hidden to
>>>> actually forward packets somewhere useful.
>>>>
>>>> Aggregated routes are on the other hand discard only, so then you need
>>>> the more-specific contributing routes with their next-hops to avoid
>>>> blackholing traffic.
>>>>
>>>> (AIUI, anyway.)
>>>>
>>>> But maybe if you enable "advertise-inactive" towards your iBGP -maybe
>>>>> then the aggregation starts to work?
>>>>>
>>>> Perhaps, but if both the generated route and its contributors are
>>>> indeed inactive in the RIB and thus not found in the FIB, then I don't
>>>> think the router would be able to forward the packets it attracts to
>>>> where it should.
>>>>
>>>> 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.
>>>>>
>>>> Yep, something like that would probably do the trick. I was hoping to
>>>> keep them out of the RIB in the first place though, to avoid having to
>>>> explicitly filter them on export to the FIB and iBGP peers, but maybe
>>>> there's no way around it.
>>>>
>>>
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