BGPath
An Online Service to Visually Analyse Streams of BGP Updates
Background Information
This page provides introductory information about BGP, BGP data sources, and BGPLay.
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Border Gateway Protocol |
The Internet is divided into tens of thousands of administrative domains
called Autonomous Systems (AS), each usually adopting a
unique routing protocol and consistent routing policies. Each AS is identified
by a number.
The Border Gateway Protocol (BGP) [RFC1771, RFC4271] is the
de-facto standard routing protocol used to exchange reachability
information between ASes. Two ASes that exchange routing information using BGP
are said to have a peering between them. A BGP router stores in its Routing Information Base (RIB) the prefixes it can reach, and for each of them an AS-path. An AS-path, also called route, is the sequence of ASes used to reach the destination prefix. Routes are propagated by BGP messages called updates.
BGP is an incremental protocol: once two BGP routers establish a peering, they exchange their whole RIB each other; this process is called table transfer. Further updates are sent only if a route changes, in response to network events (e.g., link failure, router reset, or policy change).
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BGP Data Sources |
To obtain information about the Internet routing dynamics, projects - such as the RIPE NCC's Routing Information Service - RIS and the University of Oregon's RouteViews Project - RV - spread around the world several passive collection boxes, called Remote Route Collectors (RRCs). Each route collector peers with several BGP routers, called Collector Peers (CPs), belonging to various ASes. The routing tables of all RRCs and the updates they receive are periodically dumped, permanently stored, and made publicly available.
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BGPlay |
BGPlay is a service which displays animated graphs of the interdomain routing activity in Internet of a certain prefix within a specified time interval. Namely, it visualizes
information about AS-paths used by traffic to reach a specific destination and how the AS-paths change over time.
Last Update: 11 December 2007