[c-nsp] BGP and Multihome question.

[Per Carlson]

On Sun, May 15, 2005 at 07:23:09PM -0700, Joseph Jackson wrote:
> 
> My question is this.  We have 2 /27 from our provider that we use for our
> internet facing eq since they are /27's are other providers going to ignore
> or BGP announces and thus defeat the entire point of having a multihomed
> setup?

that really depends on a lot of things, e.g.:
- is the address block part of a larger supernet maintained by the provider 
  or independent (assigned from ARIN/RIPE/...)?

- have you got an public AS or not?

- are you multihoming towrads on provider, or two (or more) providers?

if the addresses you are refering to, are regarding the domain in the email
(nos.com), and you will have dual connections to the the same provider,
there will be no problems doing multihoming. 

as far as i can tell, your /27-net is a part of a /14 belonging to your
upstream provider. that means (or *should* mean if your provider is
doing things the right way) that your /27 advertisement will only exist
in the routing table of your upstream provider. the provider will filter
it out and only advertise the /14-prefix to the rest of the world. but
that won't be a problem for you, because you probably don't care how
traffic destined to your net is being feed into your provider. 

frankly, you don't really need BGP in this case to get redundancy, static
routes or an IGP will do the trick. yes, i know that ISP's are a bit
reluctant to run an IGP towards a customer, and they prefer BGP for it's
filtering capabilities.

-- 

Regards, Per Carlson

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