Peering Exchange Configurations

Massimiliano Stucchi stucchi at
Thu Apr 8 11:25:56 CDT 2010

On 08/04/10 18:02, Brad Fleming wrote:

> 1) Is a private AS typically used for the exchange side of the session?

No.  Everybody uses his own AS number to establish sessions at peering

> 2) Are RFC1918 IPs typically used for the p2p links into the exchange?

No.  You usually get an IP address from the IX which pertains to the
IX's AS, and sits in a class that's specifically not announced to the
outside world.

> 3) Do peering exchanges typically remove their AS from the path
> advertised to exchange participants?

This is the case that happens if you use a route server.  Being at a
peering exchange point means you have the chance to sit on a switch
where other participants are directly connected.  At this point you can
either establish direct peering relationships (configuring a session for
each peering agreement you get) or create a session with the local route
server, getting routes from all the other participants.

>     3a) If no: Do participants typically preference exchange-learned
> routes over other sources?

It depends.  It's mostly a matter of economics more than a personal choice.

> In exchanges where a route server is employed:
> 4) Do participants have a p2p link into a simple routing environment
> then multi-hop to a route server?

The route server usually sits on the same LAN segment as the IXP

> 5) I see that Bird, OpenBDGd, and Quagga are all options for route
> server software. Does one of those packages stand out as the clear
> current choice for production peering exchanges?

I would say that OpenBGPd and BIRD are your best choices for this.
Quagga is getting better now, but suffered lots of problems with a high
number of peers in the past at many IXes.  That's why many migrated
either to OpenBGPd, BIRD or both.



Massimiliano Stucchi
BrianTel Srl
stucchi at

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