ADD-PATH for Route Servers

Document Type Expired Internet-Draft (individual)
Authors Pierre Francois  , Camilo Cardona  , Adam Simpson  , Jeffrey Haas 
Last updated 2015-02-13 (latest revision 2014-08-12)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


BGP speakers at Internet Exchange Points typically exchange routes with a large number of peers. To reduce the burden of maintaining many sessions, IXPs implement and administrate BGP route servers. Route servers announce to their clients the paths of multiple peers by using a single eBGP session. Route servers, however, are restricted to propagating a single path per NLRI per eBGP session. This constraint affects the diversity of paths received by clients. To overcome this limitation, we propose the extension of ADD-PATH to eBGP peers. ADD-PATH allows a BGP speaker to send multiple paths for the same NLRI, typically through different nexthops, over a single session with a peer. By supporting ADD-PATH, a route server hence allows a client to potentially select among all the available paths for that NLRI, instead of the one arbitrarily chosen by the Route Server.


Pierre Francois (
Camilo Cardona (
Adam Simpson (
Jeffrey Haas (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)