BGP protocol-neighbor PMTU Detection

BGP protocol-neighbor PMTU checks that the BGP protocol runs on TCP, so the TCP parameter settings will affect the performance of BGP. When the number of routes is small, the adjustment of TCP Parameters may not affect the BGP performance. However, when the number of routes is large, the adjustment of TCP Parameters can optimize the performance. Next, we will analyze the specific optimization methods. First, let's take a look at the BGP protocol packet sending method. See: BGP and TCP data transmission formats BGP first need to tell TCP the data they need to send, TCP segments are segmented based on the data length. The segment size is determined by the size of the MSS value negotiated by TCP. Each TCP segment corresponds to a outgoing IP packet. Therefore, the setting of MSS parameters plays a key role in the performance of BGP data transmission. If the setting is too large, it may cause IP layer fragmentation of a device in the middle, the transmission of BGP packets is actually an end-to-end transmission process. Www.2cto.com if the data is split, it must be combined and restored. This will put a certain burden on the recipient's CPU and reduce the processing efficiency; if the MSS value is set too small, the effective utilization of the network will be very low. The sender and acceptor process the packets that can be processed at one time multiple times, reducing the efficiency. The BGP neighbor PMTU detection can solve the problem mentioned above. Before establishing a BGP neighbor, the router will automatically send a PMTU report to detect the maximum MTU on the path, after this value is obtained, the TCP protocol can set the size of the MSS based on this value. When the packet is sent, the PMTU detection result is used to achieve the optimal performance.