[c-nsp] BGP into OSPF

[Dario]

We need to implement some special network.

Our customer has a link with us (statically routed) and inside his network he's running OSPF.
Due to traffic increase we need one more link and we think to implement BGP to balance traffic.

This is the final plot:

	      S0 
            |     |                        (AS766)
--------------------------- eBGP
       |               |                 (AS65xxx) 
      C1---iBGP---C2
       |               |
    ------------------
        OSPF cloud

Some customer networks (C1-nets) need to be routed via C1 and the others (C2-nets) via C2 
(and allways same way due to multicast issues). When link C1-S0 fails all traffic will go via 
C2-S0 and vice versa.

To obtain this we think to use AS-PATH attribute: customer announces C1-nets and C2-nets 
to S0 in the two BGP sessions, but C1-nets with lower AS-PATH than C2-nets in C1-SO session
(and C2-nets with lower AS-PATH than C1-nets in C2-S0 session).

We announce defaul route from S0 to C1 and C2; then C1 receives default route via S0 and 
C2 but prefers S0 (eBGP Vs iBGP), idem C2.

Configuration:

        C1: (C2 is almost the same)

                router bgp 65xxx
                        no synchronization
                        network C1-nets
                        network C2-nets
                        neighbour S0 remote-as 766
                        neighbour S0 route-map C1-S0 out
                        neighbour C2 remote-as 65xxx
                        neighbour C2 next-hop-self
                        maximum-paths 2
                        no auto-summary
                access-list 1 permit C1-nets
                access-list 2 permit C2-nets
                route-map C1-S0 permit 10
                        match ip address 1
                route-map C1-S0 permit 20
                        match ip address 2
                        set as-path prepend 65xxx

        S0:

                router bgp 766
                        no synchronization
                        neighbour C1 remote-as 65xxx
                        neighbour C1 default-originate
                        neighbour C2 remote-as 65xxx
                        neighbour C2 default-originate
                        no auto-summary

Anyone finds an error in our proposal configuration? Any unexpected bad-functioning?

Is needed any BGP distribution over OSPF in the customer network? defaul-route?

Best regards and many thanks in advance,

	Dario Donsion