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:

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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

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-----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