[j-nsp] Junos L3VPN & AS-PATH LOOP

[Rati Jokhadze]

Hi Everyone,

  I'm experiencing strange behavior with Junos L3VPN , Below is a 
simplified diagram of what I'm running. There is two PE routers, R1 
connected to the firewall with two sub-interfaces each in VRF RED and 
BLUE respectively, and R2 where customers are connected, and direct 
routes are redistributed to BGP L3VPN.
Between the FW and R1, there is an eBGP session to leak the routes 
between the two VRF RED & BLUE. Due to the default behavior of the 
as-path loop check, I have BGP Loops(Allowas-in) applied on R1 to accept 
routes from FW in each VRF Subinterface. The problem starts here. On R1 
I see that leaked Routes from the FW are accepted/installed in RIB in 
VRF RED&BLUE , but these routes are not get advertised to R2 via iBGP 
L3VPN session!.

As soon I apply as-override feature on FW to hide originating AS and 
rewrite it to 20, then everything works as expected.
Is there a special knob in Junos to Advertise "looped" routes over the 
iBGP L3VPN? I've reproduced the same setup in Cisco XR/XE and works fine 
without as-override to hide/rewrite originating-as.


Thanks!


           +---------

           |   AS20       |
           |     FW        |
           +-------+-
                   |     |
    VRF RED  |     |VRF BLUE
                   |     |
                   |     |
           +-------+|
           |  AS10       |
           |    R1 - PE  |
           +---------|
                   |
                   |
                   |
+-----------------+
|                                   |
|          MPLS CLOUD     |
|                                   |
+-----------------+
                   |
                   |
                   |
          +--------+
          |   AS10       |
          |       R2-PE  |
          +---+-----
              |          |
VRF RED|          |VRF BLUE
              |          |
              |          |
              +          +