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Re: Multihoming an end user

Pete Templin wrote:

Mailing List wrote:

We're a small shop in regards to needed address space. In other words, a full blown BGP4/ASN with a /20 allocation from ARIN isn't likely to be justified. Can this be done using a private ASN? Another option?

How big is your address usage?

Since we're able to NAT almost everything, a /29 is more then sufficient.

Keep in mind that ASN allocation and direct-from-ARIN address allocation are two separate entities. You can get an ASN if you are multihomed, about to multihome, or otherwise have a unique routing policy from your provider; it has nothing to do with how many addresses you have. With regards to addresses, you only need a /24 to successfully multihome, and you can get a /24 from your ISP. Even if you don't have enough usage to directly justify a /24, you can meet ARIN's justification requirements by multihoming (you can only get one /24 that way, and you'll have to allow all of your ISPs to check with each other on that). If you're big enough to justify a /22, you can get a /22 out of a bigger ARIN block for multihomed

My understanding was that if the addresses weren't specifically allocated to us straight from ARIN, we couldn't truly multihome. Otherwise our second ISP would try to route to our first ISP's addresses through that first ISP rather then direct through their link to us. If we apply for an ASN, can we associate our first ISP's /29 (or /24 if need be) to our ASN? Does our primary ISP need to release it to us or be multihomed themselves?

Once this is all said and done, is BGP4 on zebra the way to go or is there something better?

Thanks for your help Pete!


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