Editing Peering (section)

=== Multilateral peering ===
The majority of BGP AS-AS adjacencies are the product of multilateral peering agreements, or MLPAs.<ref name="PCH2011survey" /> In multilateral peering, an unlimited number of parties agree to exchange traffic on common terms, using a single agreement to which they each accede. The multilateral peering is typically technically instantiated in a [[route server]] or route reflector (which differ from [[Looking Glass server|looking glasses]] in that they serve routes back out to participants, rather than just listening to inbound routes) to redistribute routes via a BGP hub-and-spoke topology, rather than a partial-mesh topology. The two primary criticisms of multilateral peering are that it breaks the shared fate of the forwarding and routing planes, since the layer-2 connection between two participants could hypothetically fail while their layer-2 connections with the route server remained up, and that they force all participants to treat each other with the same, undifferentiated, routing policy. The primary benefit of multilateral peering is that it minimizes configuration for each peer, while maximizing the efficiency with which new peers can begin contributing routes to the exchange. While optional multilateral peering agreements and route servers are now widely acknowledged to be a good practice, mandatory multilateral peering agreements (MMLPAs) have long been agreed to not be a good practice.<ref name="PCHwikiMMLPA">{{cite web
 |url=https://wiki.pch.net/pch:public:ixp-policy-document#layer_3_participant_technical_requirements
 |title=Internet Exchange Point Policy Documents: Layer 3 participant technical requirements: Mandatory multi-lateral peering
 |publisher=[[Packet Clearing House]]
 |access-date=2013-10-04
 |archive-url=https://web.archive.org/web/20140809191753/https://wiki.pch.net/pch:public:ixp-policy-document#layer_3_participant_technical_requirements
 |archive-date=9 August 2014
 |url-status=dead
 }}</ref>