Geographicaly distributed AS - how to?

[iggy_wizard]

Hi.

What I have now.

3 FlexPod racks, 2 rack for Dedik. Racks are hosted in different DCs, using different ISPs PA adresses.

.....

My goal is to place 5 FlexPods and nearly two rack of dediks in 5 different DCs in differen cities. These DCs are not connected via dark fiber, I only could get Internet access. In 2 years it gonna grow to approx. 15 FlexPods and some Dediks (do not know excact number). I am about to design single network infrastructure to serve this project.

I have LIR, PI adresses and ASN as well. Is there ANY way to set up geographically distributed network that uses single PI address space, single ASN (probably one ASN per dc?)  ?

Lets assume that:

- There is no direct fiber connection between DCs

- There is no possibility to use provider's MPLS cloud to create l2vpn (too expensive)

Any advices would be greatly apreciated.

[Jason M.]

Do you have enough address space to advertise a /24 or larger block for each?

If so, you can advertise one block for each site and use the BPG allowas-in option so you can receive routes from the other sites.

[iggy_wizard]

I have /22 network.

I could brake it to advertise /24s from different locations.

Could you please point me to documents that describes such cases?

Thank in adv.

[Jason M. · Accepted solution]

Well there's a configuration example below. I would suggest lab testing it with a small topology to see how you should best configure it for your needs.

http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/112236-allowas-in-bgp-config-example.html

[iggy_wizard]

Thanr you so much!