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hackerix
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Posts: 3
Joined: Tue Sep 17, 2013 4:04 am

MPLS-TE and BGP

Tue Sep 17, 2013 4:22 am

Hi to everybody :D

small question about traffic engineering interfaces and bgp.

my backbone is composed by several rings interconnected in a sort of mesh.
loopback address, router to router routing and default route are handled by OSPF
router's local subnet are handled by BGP in (same AS for all routers) with a session per router to a single "route reflector"
which is also the default gateway for the entire net.

i've also happily got MPLS and BGP VPLS working without problems.

my doubts are about TE interfaces:
mikrotik wiki says:
Additionally, several types of traffic can be forwarded onto TE tunnel automatically, if it is known to be destined to the endpoint of tunnel and if tunnel is active:

    traffic that is routed using route route learned from BGP, if BGP NextHop is tunnel endpoint (this default behaviour can be changed by setting route porperty "use-te-nexthop" to "no"), both - regular IP and VPNv4 (MP-BGP IP VPN) routes fit in this category;
    traffic for VPLS interfaces, if remote endpoint of VPLS pseudowire is the same as TE tunnel endpoint. 

For example, for IP BGP route having BGP NextHop x.x.x.x, forwarding method will be chosen according to the following rules:

    if TE tunnel with endpoint x.x.x.x is active, use it;
    otherwise if LDP label mapping from next hop towards x.x.x.x is received, use it;
    otherwise use regular routing (no MPLS encapsulation). 
i've configured a te from the gateway to one of the router and it works out of the box.
traffic to the other router anyways continued to move along the bare interface, instead of using the te interface.

the routing table of the gateway router (where the TE interface starts)

zzz.zzz.zzz.zzz/zz ggg.ggg.ggg.ggg recursive via sss.sss.sss.sss

zzz.zzz.zzz.zzz/zz is one of the network handled by router A (the router where the te interface goes)

ggg.ggg.ggg.ggg is the loopback ip of the router A (BGP nexthop)

sss.sss.sss.sss is the nexthop for reaching ggg.ggg.ggg.ggg (OSPF nexthop)

So why bgp isn't using the te interface (which is going to ggg.ggg.ggg.ggg)?

thanks for your answers =)
 
karty
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Posts: 1
Joined: Sun Feb 02, 2014 2:25 am

Re: MPLS-TE and BGP

Sun Feb 02, 2014 4:00 pm

Hi, same problem! Have you found the solution?

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