[c-nsp] BGP/private and public ASN mix trick

[omar parihuana]

Hi,

the command remove-private-as must be configured in all egress routers
before the customer routes are advertised to other ISP. The IPS Upstreams
don't notice about internal customer, AS_PATH, don't contain private AS, the
remain BGP attributes won't be affected (of course if no changes were done)

Rgds.

On 8/25/07, Nick Kraal <nick at arc.net.my> wrote:
>
> Dear all,
>
> I have a tricky/creative arrangement here to provide to a customer.
>
> [1] The customer has their own prefixes [a.b.c.d/20], but no ASN.
> [2] We plan to run private BGP with the customer to receive this
>     prefix, and for us to announce the global routing table.
> [3] Objective is to then announce this prefix as originating from AS111
>     to all AS111 public BGP peers.
> [4] Sample configuration at the end of this e-mail. Any potential traps
>     here?
> [5] Prefix list [TUN-CUST-CIDR-BLOCK] is then used in route-maps with
>     other BGP peers. Are removing private-as and the inbound route-map
>     sufficient for BGP to pick this prefix up and announce it as AS111?
>
> Thanks in advance,
>
> -nick/
> ======================
> Current configuration:
>
> router bgp 111
> neighbor 200.100.1.10 remote-as 64001
> !
> address-family ipv4
> neighbor 203.100.1.10 activate
> neighbor 203.100.1.10 next-hop-self
> neighbor 203.100.1.10 remove-private-as
> neighbor 200.100.1.10 soft-reconfiguration inbound
> neighbor 200.100.1.10 route-map TUN-CUST-FILTER-IN in
> neighbor 200.100.1.10 route-map TUN-CUST-FILTER-OUT out
> !
> route-map TUN-CUST-FILTER-IN permit 5
> match ip address TUN-CUST-CIDR-BLOCK
> set origin igp
> !
> route-map TUN-CUST-FILTER-OUT permit 10
> match as-path 75
> !
> ip prefix-list TUN-CUST-CIDR-BLOCK seq 5 permit a.b.c.d/20
>
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-- 
Omar E.P.T
-----------------
Certified Networking Professionals make better Connections!