A Border Gateway Protocol 4 (BGP-4), January Canonical URL: https:// ; File formats: Plain Text PDF; Status: DRAFT. Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to RFC corrected errors, clarified ambiguities and updated the. RFC (part 1 of 4): A Border Gateway Protocol 4 (BGP-4).

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A group of destinations which share some common property. By using this site, you agree to the Terms of Use and Privacy Policy.

Border Gateway Protocol

RFC corrected errors, clarified ambiguities and updated the specification with common industry practices. This is also described in the following procedure.

The replacement route carries new changed attributes and has the same address prefix as 421 original route. This article’s Criticism or Controversy section may compromise the article’s neutral point of view of the subject. This procedure does not limit the rate of route selection, but only the rate of route advertisement.

Supported Standards for BGP

Route Resolvability Condition As indicated in Section 9. The router may have to keep more than one copy of a route, so it can manage different policies for route advertising and acceptance to a specific neighboring AS.

Like most other routing protocols, BGP does not detect congestion.


Their contents represent routes that are available as input to the Decision Process. The Phase 1 decision function is a separate process,f which completes when it has no further work to do. Route selection then consists of the individual application of the degree of preference function to each feasible route, followed by the choice of the one with the highest degree of preference.

An alternative to full mesh IBGP. The suggested default value for the ConnectRetryTime is seconds. This version removed the concept of “up”, “down”, and “horizontal” relations between autonomous systems that were present in version 1.

When the protocol is extended, the new behavior is fully documented in the extension specifications. That is, the NLRI of this route cannot be more specific.

This segment is then placed between the two consecutive ASes identified in a of the aggregated attribute.

Frequency of Route Origination Feasible route An advertised route that is available for use by the recipient. Vgp the other hand, BGP can support any policy conforming to the destination-based forwarding paradigm. Unfeasible route A previously advertised feasible route that is no longer available for use.

BGP, Border Gateway Protocol

Controlling Routing Traffic Overhead The term view is often used for these different policy relationships on a running router. Damping can also mitigate denial of service attacks; damping timings are highly customizable.

BGP can support only those policies conforming to the destination-based forwarding paradigm. For example, it distributes the routes chosen by the Decision Process to other BGP speakers, which may be located in either the same autonomous system or a neighboring autonomous system. In the context of this document, we assume that a BGP speaker advertises to its peers only those routes that it uses itself in this context, a BGP speaker is said to “use” a BGP route if it is the most preferred BGP route and is used in forwarding.


This, in turn, reflects the set of policy decisions that can and cannot be enforced using BGP. By eligible to be submittedBGP will submit the routes that it considers best to the main routing table process.

Border Gateway Protocol – Wikipedia

Routes that are unstable can be “penalized” e. Changing the attribute s of ngp route is accomplished by advertising a replacement route. This information is sufficient for constructing a graph of AS connectivity for this reachability from which routing loops may be pruned, and, at the AS level, some policy decisions may be enforced.

For other uses, see BGP disambiguation.

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