How does "Set BGP Prepend Path" work?

[tomasi]

Hi,

I’m trying to change AS-path inside our AS for an specific IPv4 BGP annoucement: 138.N.N.0/24

PE 7 send route to PE 10 with option Set BGP Prepend Path configured to add AS 300 before our main AS (AS 700 configured in Instance and iBGP peers)

This way I tought PE 10 would receive the BGP prefix with AS-path =

300 I

But this is not happening

PE 10 receives the iBGP route without any change:

show route 138.N.N.0/24 exact detail 
        *BGP    Preference: 170/-101
                Source: 10.7.7.7
                AS path: I

How can achieve that? I need to change AS-path received on PE 10 before send that specific BGP announcement to upstream providers

AS 300, AS 700 and AS 1000 are only examples.
In my real scenario all AS are public

Thanks

[mrz]

AS path manipulations should be done on the AS edge router. iBGP does not change AS path.

[tomasi]

This way I’ll need to install another RB just to generate the IPv4 prefix in AS 300