[BBLISA] Telecommunications Recommendations...

[Bill Bogstad]

On Thu, Jul 15, 2010 at 6:15 PM, Robert Keyes <bob at sinister.com> wrote:
>
>
> On Wed, 14 Jul 2010, Bill Bogstad wrote:
>
>>
>> While the above is technically correct, in his circumstance BGP is not
>> an option.   To do BGP you TYPICALLY need to
>> own your IP address space in order to be able to advertise them
>> successfully.  He's talking about how many addresses his provider is
>> going to give him so he doesn't have such addresses.
>
> Not really. You can get a chunk of IP space from your main provider, and
> advertise a route to it through your backup provider. This is becoming more
> common as IPv4 space is becoming a more expensive commodity.

In the past, providers would refuse to do this.  Maybe it's changed.

>
>> Second, the address space he's talking about is so small that even if
>> he does get addresses and providers who will do BGP, no one else will
>> pay attention to his advertisements anyway.
>
> Yes, this is true, you generally need a /24 (a.k.a. class C, 255 IP
> addresses) in order to be sure your route is propagated across the whole
> net. But I am a bit unusure of this, there may be ways around this problem.
>
>> Each advertisement takes
>> up expensive memory in core Internet routers and the larger network
>> providers aren't going to spend lots of money so he can have redundant
>> network providers.  Don't go there.
>
> Well yes it does take up more memory, but that doesn't mean the route won't
> propagate through BGP. I still regularly get route announcements for very
> small allocations (as small as a single host!), and people won't announce or
> propagate such routes if they didn't have value.

If you are "very important" networks will allow smaller allocations
through. I think some of the DNS root servers are using "anycast" and
small BGP announcements for redundancy purposes.

I still think this is likely to be a non-starter for someone in the
original poster's situation.
However, if he wants to pursue it; he could go look at the archives
for the NANOG mailing list for what is typical practices on BGP
announcements.

Bill Bogstad