Glossary

Advertise

Announce.

Aggregate

  1. To announce a single, shorter prefix in place of several longer prefixes.

  2. A shorter prefix that replaces several longer ones.

Announce

To send out BGP route updates indicating that a certain destination network (prefix) is reachable as part of the local AS.

Anycast

Packets sent to an anycast address are delivered to a single member of the associated anycast group the address belongs to. IPv6 anycast addresses follow regular unicast semantics, i.e., a system doesn’t know it is sending a packet to an anycast address rather than a regular unicast address.

AS

Autonomous System.

AS number

Autonomous System number, a 16-bit value used in BGP (and EGP) processing for detecting routing loops and applying policies.

AS path

A list of AS numbers including the source of a route announcement (on the right), the next hop AS (on the left), and all ASes in between.

Autonomous System

“An AS is a connected group of one or more IP prefixes run by one or more network operators which has a single and clearly defined routing policy” (RFC 1930).

Bandwidth

Information transfer capacity, usually measured in (kilo-, mega-, or giga-) bits per second.

BGMP

Border Gateway Multicast Protocol. Protocol for interdomain multicast routing. Has no direct relationship to BGP.

BGP or BGP-4

Border Gateway Protocol (RFC 1771). BGP Version 4 is the routing protocol currently used for interdomain routing in the Internet.

BGP4+

BGP-4 with multiprotocol extensions (see MBGP).

Black hole

A router or AS announcing ...

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