BGP (Border Gateway Protocol) is a routing protocol used to connect independent systems on the Internet. It is an enhanced, complete and scalable protocol formulated by the Internet Engineering Task Force. BGP4 supports the CIDR addressing scheme, which increases the number of IP addresses available on the Internet. BGP is designed to replace the original external gateway protocol EGP. It is also considered a path vector protocol.
BGP is mainly used for interconnection between Internet AS (autonomous systems). The main function of BGP is to control the propagation of routes and select the best routes. China Unicom, China Telecom, China Railcom and some large private IDC operators all have AS numbers, and most major network operators across the country implement multi-line interconnection with their own AS numbers through the BGP protocol. To use this scheme to achieve multi-line interconnection, IDC needs to apply for its own IP address segment and AS number at CNNIC (China Internet Information Center) or APNIC (Asia Pacific Network Information Center), and then broadcast this IP address to other addresses through the BGP protocol The network operator’s network. After using the BGP protocol to interconnect, all backbone routing equipment of the network operator will determine the best route to the IP segment of the IDC computer room to ensure high-speed access for users of different network operators. The computer room that uses the BGP solution to realize dual-line interconnection or multi-line interconnection is called BGP computer room.
1. The server only needs to set an IP address, and the best access route is determined by the backbone router on the network according to the route hop count and other technical indicators, and will not occupy any system resources of the server. Both the upstream route and the downstream route of the server can choose the optimal path, so it can truly realize high-speed single IP high-speed access.
2. Because the BGP protocol itself has the characteristics of redundancy backup and elimination of loops, when IDC service providers have multiple BGP interconnection lines, they can realize mutual backup of routes. When one line fails, the route will automatically switch to other lines.
3. Using BGP protocol can also make the network have strong scalability. IDC network can be interconnected with other operators, and single IP multiple lines can be easily realized, so that users of all interconnected operators can access quickly. This is incomparable with dual IP dual lines.
BGP is a routing protocol between autonomous systems. Its main function is to exchange network reachability information with other BGP speakers. A BGP speaker is any device configured for BGP. BGP uses TCP as its transport protocol (port 179), which provides reliable data transmission.
Two BGP routers form a transport protocol connection. These two routers are called neighbors or peers. Once the transmission connection is formed, the two pairs of routers exchange messages to open and confirm the connection parameters. In this step, the router exchanges information such as BGP version number, AS number, duration, BGP identifier, and other optional parameters. If any parameter between the peers is inconsistent, an error notification will be sent, and the peer connection will not be established.
If the peer routers agree with these parameters, the entire BGP routing table is exchanged through UPDATE messages. The UPDATE message contains a list of reachable destinations passing through each system (ie, network layer reachability information NLRI) and path attributes of each route. The path attribute contains information such as the origin of the route and the level of priority.
The BGP table is valid for each peer during the BGP connection. If there is a change in routing messages, neighbor routers use incremental updates (messages) to transmit this information. BGP does not require refreshing routing information. If no routing changes occur, BGP peers only exchange keepalive packets, and keepalive packets are sent periodically to ensure that the connection remains valid.
The BGP computer room is a related network technology used by server renters to realize that different operators can access one IP together, and the fastest access speed can be achieved between different operators.
The BGP computer room solves the problem of north-south intercommunication between users to a certain extent, and improves the access speed of users. The effect of single-IP dual-line realized by BGP protocol. The solution is to directly map the IP of one line to the IP of the other line through the BGP protocol. When visitors browse your website, they will automatically select the line with the fastest access speed according to the actual situation, so that users of all operators can To achieve the best access speed.
1. The leased server has only one IP, and the user's access route is selected by the router according to the visitor's actual access speed to select the optimal access path. And does not occupy any server resources. Both the upstream and downstream of the server have routers to choose the best route, so this can truly achieve the best access speed between all operators and realize the real BGP effect.
2. Because the BGP protocol itself has the characteristics of redundant backup and elimination of loops, it can realize mutual backup when the server you host or rent fails. At the same time, it will automatically switch to other lines without affecting normal access.
3. BGP server lease also has better scalability and integration, which can realize interconnection and intercommunication with other operators, and easily realize single IP and multiple lines, so that users of all interconnected operators can access quickly. This is something that cannot be achieved with dual-IP dual-line server lease.