Joining an IXP

An IXP is the easiest way to interconnect with multiple networks at the same time. An IXP is typically a large L2 switching fabric., therefore an IXP has no Gateway IP.

At most IXPs there are Route Servers, RS, which help Peer with other participants of the IXP. A Route Server distributes routes between participants making it not necessary to build direct BGP Sessions with all IXP Members.
Usually there are two Route Servers, eg. at FogIXP: PeeringDB.org

Before sending a joining request to an IXP its recomended to create a PeeringDB account: peeringdb.com/register

IXP Netiquette

There are a couple things you should not do on an IXP, some peers and IXPs may enforce it less, some more. To avoid any troubles we recomend following those points.
-Do not send any non-BGP protocols over the Peering LAN (eg. OSPF, Bonjour, Zerotier, Proxy ARP, STP).
-Dont mass mail peers that are already on the Route Server and sending all prefixes.
-Only send traffic to destinations advertised by BGP on the Peering LAN (not pointing static routes)

Peering Configuration

When Peering with an IXP route server or also directly with other networks we would want to make sure a couple of things:
-Not importing any Tier-1 ISPs as we can assume, they will never peer at an IXP (Hurricane Electric is a debatable exception).
-Setting a higher preference than we have on any of our Transit links, like 400 (this is debatable, some disagree some encourage it)
-Set a prefix import limit by adding an import limit to our config so that a peer cannot send us a full table, which effectively minimizes the impact of a misconfiguration.

When peering on an IXP our peering partner will most likely tell us how large the max-prefix should be, in addition its also visible on peeringdb.org

Our config would then look like this:

protocol bgp IXP_Peering {
    import filter {
    import limit 1000 action block;