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Is it possible to use BGP to announce serving IP addresses without owning an AS number? Aim is to adding another WAN provider and increase redundancy with the ability to announce IP addreess from to healthy link. If not, what can you suggest me for the aim?

Regards, hmmmmm

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up vote 1 down vote accepted

Not recommended, and I don't believe you would find providers willing to do so.

A Private ASN should be used if an AS is only required to communicate via BGP with a single provider. As the routing policy between the AS and the provider will not be visible in the Internet, a Private ASN can be used for this purpose.

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You could use private AS number (64512 through 65534) for BGP routing but you'll need to negotiate this with your uplink providers.

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We do this with dual links to one provider AS. – dmourati May 25 '11 at 4:47

BGP is an EGP (exterior gateway protocol), for WAN redundancy you are better off using an IGP (interior gateway protocol) such as OSPF or EIGRP.

Both protocols will do what you want, which to choose is more a matter of taste and minor requirements, EIGRP is Cisco proprietary and OSPF is vendor neutral. My choice is always EIGRP as it's slightly simpler to configure and monitor and all our routers are Cisco. OSPF offers slightly more flexibility for large networks.

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He is talking about an exterior gateway, and policy based routing may be important there. – TomTom May 25 '11 at 6:57
"WAN provider" to me suggest an internal network link between private sites, not external connectivity. Plus PBR doesn't depend on the routing protocol, it works with either. – HampusLi May 25 '11 at 8:11
Ah, WAN provider suggests to me an internet provider (external conncetivity) or two PROVIDING wan connectivity. I was offered BGP from my uplinks as well as my data center to optimize routing between us. – TomTom May 25 '11 at 11:03

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