Ok got you now, so if I get route X to a “RR” and modify its attributes based on existence of route Y on export to other PEs including the PE that was supposed to introduce the route in the first place, then that would work.
But route X is actually used for forwarding, so it would have to have its NH altered to point to the PE that was supposed to advertise it. And a copy of route X for PE that was supposed to introduce it –would have to have its next hop altered to point to the egress interface. Ok so this is how it would work for the very basic functionality, i.e. if route Y exist then alter attributes of a route X that is being introduced to a local AS. Ok so if I kept these trigger routes in a separate trigger VRF, I could use say: 1.1.1.120 –to set LP=120 1.1.1.80 –to set LP=80 1.1.2.200 –to set MED=200 But for a more complex case where route Y is not just some made up trigger route but actual forwarding route where one would like to be looking at its attributes like IGP metric to a NH, then RR might have a different view than the PE that was supposed to introduce the route into a local AS. adam netconsultings.com ::carrier-class solutions for the telecommunications industry:: From: Alexander Arseniev [mailto:[email protected]] Sent: Wednesday, March 15, 2017 4:16 PM To: [email protected]; [email protected] Subject: Re: [j-nsp] conditional route import My idea is based on what is working in JUNOS today, it is called "conditional EXPORT". Yes, unmodified route would be visible only on RR and not used for actual forwarding, that's the purpose of modifying it in 1st place, isn't it? Your idea to make route attribute change to work conditionally on IMPORT requires adding code to JUNOS. Your choice what You want to use and when :-) Thx Alex On 15/03/2017 10:23, [email protected] <mailto:[email protected]> wrote: Although I’d prefer that the router which introduces the route X to a local AS performs the desired attribute changes to the route X, it doesn’t matter whether it’s the PE or a RR –still the same requirement holds true. PE or RR(in your example) needs to look into its routing table to see if route Y exist and based on that change attributes of an incoming route X. Yes I could change attributes of route X while I advertise it to RRs (on export from VRF). - but that would make the PE which introduced route X to a local AS oblivion to routing change that’s apparent to everyone else in the AS, which is not desirable adam netconsultings.com ::carrier-class solutions for the telecommunications industry:: From: Alexander Arseniev [mailto:[email protected]] Sent: Tuesday, March 14, 2017 5:57 PM To: [email protected] <mailto:[email protected]> ; [email protected] <mailto:[email protected]> Subject: Re: [j-nsp] conditional route import Hello, If You pass this route to BGP RR and do modifications there before advertising it to target PE, where it is installed with modified parameters then You'd achieve Your objective. BGP RR in this case plays the role of "external controller". You can even have interface peering extended to BGP RR via L2circuit so PE does not even learn the original route, it installs modified one. This avoids the complexities with sending the modified route back to originator PE I mentioned earlier. Hope this makes sense. Thx Alex On 14/03/2017 11:23, [email protected] <mailto:[email protected]> wrote: Hi Alexander, No in my example I need to modify parameters of route X, based on parameters of route Y. That seem to be impossible in current versions of network codes (other than via external controller) adam netconsultings.com ::carrier-class solutions for the telecommunications industry:: From: Alexander Arseniev [mailto:[email protected]] Sent: Monday, March 13, 2017 12:28 PM To: [email protected] <mailto:[email protected]> ; [email protected] <mailto:[email protected]> Subject: Re: [j-nsp] conditional route import Hello, You can do it easily in BGP Route Reflector export policy coupled with other features like ORR and NH rewriting. There could be complexities with PE config (obviously, the PE would prefer eBGP route direct from CE vs iBGP from RR) but they can be overcome with routing-instances. HTH Thx Alex On 12/03/2017 10:32, [email protected] <mailto:[email protected]> wrote: Hi folks, Anyone tried to use "if-route-exists" or the "rib has route" condition for route import as opposed to the more usual route export or default route origination respectively? Can't find it documented anywhere and it's not working, but I'm just curious what are your thoughts on the concept of general routing behaviour programmability using routing information. I need the network to reprogram itself based on routing events without the YANG/NETCONF complexity. And for that I'd need a route and it's specific parameter or a set of parameters to be used as an instruction or a trigger. I'd like to be able to use a more general from of condition in routing-policies (or even forwarding filters or QOS-policies). Example: condition_1 if (route = x.x.x.x/x in VRF A) AND (igp metric to NH < 100) then condition_1 == TRUE route-policy 1 if route = y.y.y.y/y AND if condition_1 == TRUE then set local-preference 120 AND accept bgp VRF A neighbour z.z.z.z route-policy 1 in Options: The trigger route can be constructed at the trigger router and advertised into an intended VRF or to a separate "instructions-VRF", dedicated to contain these special purpose routes if we don't want to mix these instruction routes with regular routing information. Or the trigger route could be a regular routing info with a specific set of attributes that we intend to use as a marker of a specific network event that we want to act upon in case it happens. I'd appreciate any feedback. adam netconsultings.com ::carrier-class solutions for the telecommunications industry:: _______________________________________________ juniper-nsp mailing list [email protected] <mailto:[email protected]> https://puck.nether.net/mailman/listinfo/juniper-nsp _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
