[j-nsp] Advertising inactive routes to iBGP neighbors

[Nathan Ward]

> 
> On 18/04/2022, at 3:49 AM, James via juniper-nsp <juniper-nsp at puck.nether.net <mailto:juniper-nsp at puck.nether.net>> wrote:
> 
> 
> From: James <james at nexril.net <mailto:james at nexril.net>>
> Subject: Advertising inactive routes to iBGP neighbors
> Date: 18 April 2022 at 3:49:44 AM NZST
> To: juniper-nsp at puck.nether.net <mailto:juniper-nsp at puck.nether.net>
> 
> 
> Hi all,
> 
> I have two routes in inet.0, neither of which come from BGP:
> 
> 10.200.7.2/32      *[Static/5] 00:14:40
>> to 10.200.7.2 via irb.102
>                    [EVPN/7] 00:08:25
>> via irb.102
> 
> I want to advertise the 'EVPN/7' route, either alongside or completely in place
> of the 'Static/5' route. The particular use case here is EVPN-VXLAN virtual
> machine traffic optimization, where I want to advertise the EVPN route with a
> higher localpref to steer traffic towards one or more particular leaf switches
> while still advertising the static route as a fallback in case the EVPN route
> is not there. Normally this works because the attached prefixes are longer than
> a /32, but I just can't seem to figure out how to make this work with /32
> statically routed prefixes.
> 
> I've already tried several methods including rib-groups to bring the route into
> another table (no support for rib-groups with EVPN routes), bgp add-path
> (doesn't advertise the second path), and playing with route preferences
> (static route needs to be the active route for forwarding purposes), but none
> of those have been successful.
> 
> Any other suggestions on how I could achieve this?

I’m not sure I entirely understand the purpose behind what you’re doing. I read the follow up message and still don’t quite get why you need a static to make this happen, but.. is the /32 thing because in JunOS by default doesn’t advertise /32s in EVPN?

You can change this with policy in protocols evpn ip-prefix-routes export <blah>.

https://www.juniper.net/documentation/us/en/software/junos/evpn-vxlan/topics/ref/statement/ip-prefix-routes-edit-routing-instances-protocols-evpn.html <https://www.juniper.net/documentation/us/en/software/junos/evpn-vxlan/topics/ref/statement/ip-prefix-routes-edit-routing-instances-protocols-evpn.html>

--
Nathan Ward