[j-nsp] BGP add-path on QFX

[adamv0025 at netconsultings.com]

> From: Vincent Bernat [mailto:bernat at luffy.cx]
> Sent: Friday, January 27, 2017 2:41 PM
> 
>  ❦ 27 janvier 2017 14:17 GMT, <adamv0025 at netconsultings.com> :
> 
> >> I am using some QFX as route reflectors and would like to use BGP
> >> add-path feature. The documentation says that QFX is a supported
> >> platform[0] while the feature explorer says no QFX has support for
> that[1].
> >>
> >> [0]:
> >>
> http://www.juniper.net/techpubs/en_US/junos16.1/topics/example/bgp-
> >> add-path.html
> >> [1]: https://pathfinder.juniper.net/feature-explorer/feature-
> >>
> info.html?fKey=3294&fn=For+internal+BGP+(IBGP),+advertise+multiple+pa
> >> t
> >> hs+to+a+destination
> >>
> >> I have upgraded some QFX to 16.1R3 but there is no difference with
> >> 14.1X53-D40: add-path is an hidden command and only "receive" is
> >> available ("send" is not accepted):
> >>
> >>   set protocols bgp group batman family inet unicast add-path send ...
> >>
> >> I have also tried on MX104 running 14.1R8. Feature explorer says this
> > should
> >> be supported since 13.2R2. But I am in the exact same situation:
> >> add-path is a hidden command and only "receive" is available.
> >>
> >
> > Is the RR use in MPLS-VPNs environment or just pure L3-IPv4/6
> environment?
> > If it's MPLS-VPNs environment, then you don't need add-path.
> 
> It's in a pure L3-IPv4/IPv6.
> 
> > Also if ORR is supported on QFX by any chance you might want to try
> > that instead of add-path.
> > Does it take the below?
> > set protocols bgp group batman optimal-route-reflection
> 
> Yes, it's accepted. But my goal is to get load balancing to a set of hosts, not
> optimal path (all routes are equal in my setup). My understanding of the
> above option is that it still selects only one route.

Actually never mind, in pure IP environment you'd still need add-path/diverse-path feature to get the alternate ORR paths across to clients.

But actually the whole purpose of ORR was to distribute primary as well as alternate/backup paths, but in an optimal way, as opposed to brute force *all paths(Type1 RDs) or inefficient primary/backup paths(add-paths). 
 
The Junos configuration actually allows for manual definition of primary and backup virtual location. 
(hoping for automatic and/or policy-based primary and best backup selection in future). 

*The number of paths advertised with this approach can actually be scaled down with careful assignment of RDs among given set of AS-exits. 


adam

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