nanog mailing list archives

RE: de-peering and peering


From: "Kris Foster" <Kris.Foster () telus com>
Date: Thu, 4 Apr 2002 12:59:49 -0700


Let us say Network A has a peering Agreement with Network B. 
Now let us 
say Network X wants to reach Network B. X and B do not have a peering 
agreement. Can Network A use the peering Link between A nd B to route 
the traffic of network X.

If there is an agreement in place (ie. A and B exchanging customer prefixes
and X is a customer of A). 

What are the mechanisms in place in B's network to detect 
that Network A 
is transiting the data( in this case network B looser) from Network X?

You should be able to filter.  RADB is one solution that may make it more
manageable.  But if your not filtering it will still require a transit
provider to get  the traffic back to X (think asymmetry).

Kris


masquerading transit data as if its originating from its own n

Steve Naslund wrote:

Peering arrangements are when networks make connections 
between each other.
Usually networks of
equal size (traffic wise) will try to peer with each other. 
 Although this
may not be technically correct here
are the basics.

Peering - connections between networks that our 
cooperative, there is no
cost other than the physical
connection itself.  That cost might be shared or the 
smaller network may pay
for the physical connection.
Carries traffic that terminates on one of the two networks. 
 i.e. you can't
go through the peering connection
you have with my network to get to another network.  
Consider peering
connections to be express routes between
two networks.  You generally can get this type of 
connection if you are a
service provider or public institution.
It is harder to get if you are a private entity unless you 
can show a
benefit for me in peering with you.  In
other words, I would like the traffic flow to be as 
symmetric as possible or
improve service for an important
customer.

Transit - connections between networks that I pay for an 
allow me to get to
anything on the Internet.  These
are generally very expensive but allow you to reach anyone, 
anywhere.
Consider transit connections to be the
superhighway with exits to everywhere but with a lot of 
traffic.  Anyone who
buys service from an upstream
provider has a transit connection although they usually 
refer to full BGP
sessions.

Now you can see that if I am paying for a transit 
connection through say
UUnet and I have a ton of traffic going
to say Exodus, it is in my best interest to try to 
establish a peering
agreement with Exodus so that I don't have
to use my expensive bandwidth from UUnet.  I can also get a 
more direct
route to where my customers want to go and
avoid congestion.

Peering and de-peering have a huge impact on traffic 
engineering because
lack of peering means that most traffic
is being carried by the biggest transit providers like 
UUnet and Cable &
Wireless.  Peering makes the Internet
more redundant and reliable and evens out the loads better.  Traffic
engineering is all about peering and which
paths are preferred over others.  I your only connections 
are transit then
there are not many options for
traffic engineering.

Steve


-----Original Message-----
From: owner-nanog () merit edu 
[mailto:owner-nanog () merit edu]On Behalf Of
Shashi Kumar
Sent: Tuesday, April 02, 2002 12:36 PM
To: nanog () merit edu
Subject: de-peering and peering


Dear List:

   Sorry for a naive question. Could some one on the list explain what is
peering and de-peering ? and how peering and de-peering influence
traffic engineering?. ( data traffic or otherwise..)

thanks in advance,
shashi









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