[j-nsp] Route Reflecting & Next-Hop Self

[Sean Clarke]

Hi Dan

You may want to use the "external" keyword in your policy. This way you 
only set nhs to the external bgp routes, not ones learned via iBGP.

i.e.

policy-options {
    policy-statement nhs {
        from {
            protocol bgp;
             external;
        }
        then {
            next-hop self;
            accept;
        }
    }
}

cheers
Sean


Dan Armstrong wrote:
> I'm new to JunOS, coming from IOS - and I'm having a heck of a time 
> wrapping my brain around something that should be fairly simple...
>
>
> eg:
>
> If I am a route-reflector server.  I also have eBGP sessions.  My ebgp 
> session's next hop is in 'other people's' address space, so I don't 
> carry it in my IGP, so I use next-hop self...  Seems fairly normal and 
> common right?
>
>
> In IOS, if I set next-hop self in a neighbor relationship with an 
> RR-Client, it sets the next-hop to itself for routes learned from 
> local eBGP sessions, but leaves the next-hop unchanged for routes that 
> it's passing on from other fellow route-reflectors...
>
> The *problem* is that in JunOS, if I set next-hop self on a neighbor 
> relationship with an RR-Client, it sets the next-hop to itself all the 
> time, even on routes it's passing on from other fellow 
> route-reflectors, effectively sucking all traffic into the route 
> reflector and totally defeating the purpose of route reflecting.
>
> Now, of course we can policy-statement our way out of this - with big 
> messy kludgey stuff, but it seems to me that there has to be a fairly 
> simple and elegant way to do this, since it's pretty common, no?
>
>
> (My current kludge is to set an import policy on my eBGP sessions that 
> tag each route with a community called "HERE", have an export policy 
> towards all my iBGP neighbors to set next-hop self if the route is 
> tagged with the community "HERE", then strip it off - so that the 
> community "HERE" never leaves any box.)
>
>
>
>
>
>
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