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Re: Non-ISP companies multi-homing?
From: root () gannett com
Date: Thu, 24 Jul 1997 14:10:05 -0400 (EDT)

On Thu, 24 Jul 1997, Gordon Mercer wrote:

You wrote:

Without the ISP having total control over the customer
router, a misconfiguration of filters on the customer
side could easily cause the customer to be a valid (and
1 hop) path in the tables from ISP A to ISP B. Doesn't
sound like a possibility I would be willing to have
hanging over my head.

Well, since my bandwidth is necessary for my business, I
think I'd be much more concerned about becomming the
valid route than my upstreams, if they get better routing
through me, it's not necessarily a bad thing for them
unless they're concerned about me snarfing traffic.

They've also got to worry about your bandwidth, which  
could become a big issue depending on the size of the two  
providers involved.

If they've oversold their provisioning, then yes, they would, but I can't 
see how other than that they would.  Perhaps I'm missing something?  In 
my particular case, my upstreams are UUNet and BBN, and I've been 
particularly happy with the current arrangement.

In the particular scenario being discussed, which routes  
would you want from your upstream? You might want full  
routes for the ability to actually choose best path, and  
then the upstream providers loose control over what you  
are sending where.

I get full routes from my peers.  That doesn't mean they send me traffic
based on destination addresses outside of those specifically linked to my 
AS.  Why would they route traffic destined to someone else through my
path if they were paranoid about me polluting things?  I'd expect them to
no do that as much as I expect them to not accept routes advertised by 
me that aren't  in the address blocks I've specified.  Maybe I'm missing 
something here, but it seems pretty cut and dried, and other than the 
filtering/CPU issues I don't see a major downside.  Certainly my 
upstreams didn't seem to have a problem implementing it, and it's saved 
us bigtime a number of times since we started it.

I'm sure you know exactly what you are doing, but not  
every Joe that a provider takes on does. My point is only  
that this is a situation that I would not want to bring  
upon myself.

I can understand that.  In my case, it was a couple of years in coming, 
but we'd planned for it at the start, and gotten agreements from the 
providers to do it during circuit upgrades.  I'd have dropped a provider 
who wouldn't have agreed, since I had it as a critical need which it took 
a while to get funded, and to get management to buy in to.  

Long-term, I'm more concerned with the route aggragation problems once 
other folks start jumping on the bandwagon than I am with any particular 
application, mine included.  Not just because I'm carrying full tables, 
but because CIDR was a necessary evil, and we're basically moving towards 
negating its advantages.

Paul D. Robertson
gatekeeper () gannett com

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