Border Gateway Protocol/Advanced

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An advanced level version of Border Gateway Protocol.

A number of advanced BGP protocol functions have been developed to improve the scalability, robustness, and security of BGP. This page introduces them; see feature-specific articles for additional details and applications.

iBGP scalability

See also: route reflector
See also: BGP confederation

One of the major scalability problems of BGP over TCP, which can be tuned on a local basis, is that TCP takes a substantial amount of processing, as can the per-interface issues of BGP setup, advertising, and acceptance. Two techniques, route reflectors and BGP confederations can reduce the need for the high overhead of full meshing. The methods can be used in conjunction wit one another.

eBGP scalability


Route servers

Policy signaling

BGP communities are attributes that can be used to identify a related group of routes.[1] There are both well-known communities that should be recognized by all BGP implementations, and various kinds of communities that are usually defined by an autonomous system [2]

To deal with Internet growth and the use of BGP in intranets and extranets (e.g., virtual private networks), various extended communities have been defined. [3]

Confederations for policy

BGP confederations are sets of autonomous systems, as distinct from communities, which are sets of routes.[4] In practice, confederations are most often used as ways to get finer policy granularity within an autonomous system visible on the Internet. For example, if AS number 1 is visible, it might internally use AS 64000, 64001, and 64002 to impose policies relevant to its internal routing flow.

Route selection algorithm

  • Load balancing specifics

Security architecture

Trusted registries


  1. Chandra R., Traina P., Li T. (August 1996), BGP Communities Attribute, RFC1997
  2. There are communities, typically used in intranets and extranets, where a prefix other than an autonomous system number is used to disambiguate
  3. Tappan D., Rekhter Y., Sangli I. (February 2006), BGP Extended Communities Attribute, RFC4360
  4. Traina P., McPherson D., Scudder J. (August 2007), Autonomous System Confederations for BGP, RFC5065