Multi-Homed Routing

Tom tom at
Mon Sep 1 21:26:41 PDT 2003

On Mon, 1 Sep 2003, Haesu wrote:

> On Mon, Sep 01, 2003 at 11:24:33AM +0200, Sten Daniel S?rsdal wrote:
> > [.snip.]
> > >
> > > this solution would work if you had alot of extra cash
> > > stashed away, just
> > > waiting to be used, which i dont think is the case here. yes
> > > bgp is the
> > > accepted solution but is way too expensive to implement.
> > >
> > Aye
> Yes and no. If you use some residential ISP or some cheapo local isp
> that doesnt even know how to configure BGP, then yes it is expensive
> path to take.
> If you already have competant provider as your upstreams, turning up bgp
> is just a matter of typing 'portinstall zebra' and get AS number from
> RIR and request minimum of /24 from LIR. Then just register your /24 at
> ALTDB for free.

  Assuming your IP registry will provide you a /24.  For those in the
Americas, ARIN will not give you anything less than a /19, and you need to
prove that you can use most of it within 6 months.  That means most small
providers can't go this route.

  Plus, some have suggested just advertising your existing assignments
from your other provider.  Bad idea.  Most providers address allocated
is not portable.  Check WHOIS for "ADDRESSES WITHIN THIS BLOCK ARE
NON-PORTABLE".  Besides, even if your existing provider's IP blocks work,
and your provider allows you to do this (you should always ask first),
you'll be advertising a more specific prefix of one of their larger
blocks.  Guess what that will do?

  ALTDB?  Route registry is only as good as good as the networks that use
it.  There are so many registries now.  RADB is ok.  You have to pay a
a small yearly admin fee.  But that means that they can have actual staff
to make sure everything is up to date.  Any route registry that allows
anyone and their dog to register anything, isn't going to something that
big tier 1 providers are going to trust to build route policies.

> BGP *may* be expensive, but it truly is scalable and fully configurable
> for hosting applications. I.e. I can play the whole BGP game to route x
> amount of my customers via some cheap bandwidth provider, or some cust
> blocks out via premium bandwidht providers, etc, etc It's definately a
> powerful tool if you are up for it.

  But you need to know what you doing.  If you dump the routing table,
you'll see that many networks can't even do basic route summaries.

> -hc
> --
> Sincerely,
>   Haesu C.
>   TowardEX Technologies, Inc.
>   WWW:
>   E-mail: haesu at
>   Cell: (978) 394-2867


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