What is the router bgp protocol

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What is the router bgp protocol? Border Gateway Protocol (BGP) is a routing protocol used to connect independent systems on the Internet. It is an enhanced, complete and extensible protocol developed by the Internet Engineering Task Force.

Bgp protocol is mainly used for the interconnection between the internet as an autonomous system. its main function is to control the routing and choose the best propagation path. Using this scheme to realize a single IP multi line needs to be directed to the CN (China Internet Information Center) applies for IP address segment and AS number, and then broadcasts the IP address to telecom, internet, mobile and other operators through BGP protocol.

After the BGP protocol is used for interconnection, the backbone routing equipment of the operator will judge the IP segment and the optimal route of the machine room to ensure high-speed access of users, such as telecommunications, interconnection, mobile and education networks check for 500-470

Characteristics of bgp routing protocol

  1. BGP uses TCP as its transport layer protocol (the listening port number is 179), which improves the reliability of the protocol.
  2. BGP performs inter domain routing and requires high stability of the protocol. Therefore, the high reliability of TCP protocol is used to ensure the stability of BGP protocol.
  3. BGP peers must be logically connected and TCP connected. The destination port number is 179, and the local port number is arbitrary.
  4. BGP supports classless inter domain routing CIDR.
  5. When the route is updated, BGP only sends the updated route, which greatly reduces the bandwidth occupied by BGP propagation routes and is suitable for spreading a large amount of routing information on the Internet.
  6. BGP is a distance vector routing protocol, which avoids the occurrence of loops in design.
  7. Between ASs: BGP will discard the route with the local AS number through the AS that carries the AS path information mark, thus avoiding inter domain loops.
  8. Internal to the AS: The routes learned by BGP in the AS will not be forwarded in the AS, avoiding loops in the AS.
  9. BGP provides rich routing policies, enabling flexible filtering and selection of routes.
  10. BGP provides a mechanism to prevent route oscillation and effectively improves the stability of the Internet network.
  11. BGP is easy to expand and can adapt to the new development of the network.

The BGP two-wire scheme has the following advantages:

  1. The server only needs to set one IP address. The optimal access route is determined by the backbone router on the network according to the number of route hops and other technical indicators. It will not occupy any system resources of the server. The server’s upstream and downstream routes can both choose the optimal path, so it can really achieve high-speed single IP dual line access.
  2. Because the BGP protocol itself has the characteristics of redundant backup and loop elimination, when the IDC service provider has multiple BGP interconnection lines, it can realize mutual backup of routes. When one line fails, the route will automatically switch to other lines.
  3. The use of BGP protocol can also enable the network to have strong scalability. It can interconnect the IDC network with other operators, easily realize single IP multiple lines, and achieve fast user access for all interconnected operators. This is incomparable with dual IP and dual line.

Although the BGP solution is the best solution, because this solution requires large equipment and bandwidth investment from IDC providers and is technically complex, the current domestic adoption of this solution is limited to strong professional IDC service providers.


  • Post published:September 6, 2023
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  • Post category:Tips

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