North American Network Operators Group

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Re: Backbone IP network Economics - peering and transit

  • From: Stephen J. Wilcox
  • Date: Tue Apr 20 14:23:41 2004

On Tue, 20 Apr 2004, Patrick W.Gilmore wrote:

> In many, many cases, especially for smaller providers, this is a spare FE on a
> switch which already exists.

I assume Vijay meant the cost of a port for private peering, in which case if 
you private with all your peers and you have a lot of small peers thats going to 
be a lot of cost for a few kbps of traffic

> > - Operational costs such as legal review for BLPAs, NOC monitoring,
> > troubleshooting when it flaps, putting MD5 on, etc
> 
> These costs are frequently quoted as reasons not to peer by the larger 
> providers.  
>
> BLPAs are only required by people who think they mean something.  

Well theyre a good excuse thats for certain :) But I would say they do mean 
something.. if you're BigISP-A and you are peering with BigISP-B you want to 
make sure that continues reliably and that means a formal arrangement. Even if 
your a small ISP its worthwhile considering a formal arrangement particularly 
with the larger peers to make sure they dont ditch you without some good notice 
or that they will upgrade without cost if your traffic increases....

> In general, Peering is a Good Thing [tm].  It increases performance, can lower
> costs, and might even increase your network reliability.

Hmm, we're fairly open on peering and have a bunch of small peers, in fact most 
of our new peerings are with small peers (small is something like announcing a 
single /24 and doing almost no traffic).

We occasionally see performance problems with these small peers, where they 
maybe drop the session without warning raising an alarm here or do something 
screwy with their config and leak or whatever.

They also tend to only have one connection, this forces how we route traffic to 
them, as we're in the process of expanding I really want to have multiple equal 
paths so that we can be sure the traffic is taking the best way to them.

My summary of these points is that I'm seriously considering what our policy 
will be in the future and for good reason (altho it will undoubtedly continue to 
be fairly relaxed).

> If your monthly costs are lower with peering than transit alone, it is
> probably a good idea to peer and ignore the NOC costs.

In some instances I'm willing to pay more for a connection (eg paid peering or
costs of backbone circuits) to ensure I'm receiving quality.

There are a couple other issues not raised... 

One is the cost on the router in terms of memory and cpu of maintaining such a
large number of sessions (usually less of an issue with your big multiprocessor
routers)

The other is our new hot topic of security, not sure if anyone has thought of
this yet (or how interesting it is) but the nature of the bgp attack means that
if you can view a BGP session you can figure things about a peer that would
otherwise be hidden from you in particular the port numbers in use.. and I'm not 
entirely clear on the details but it sounds like when you hit the first session, 
you can take the rest out very easily.

We cant take BGP out of band (yet!), perhaps we can keep it better hidden from 
view tho..

Steve