Method for transmission processing IP fragment message

Abstract

The invention relates to an IP fragmentation message transmitting method, applying ICMP message on network equipment, making user end or network server end automatically regulate message size, thus avoiding message recombination in intermediate equipment. It solves the problems of high cost and implementing complexity in message recombination by hardware, and performance of message recombination by software. And it is simple to implement and does not influence transmission performance.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a method for transmitting and processing IP fragmented messages. Background technique [0002] At present, with the cross-regional and transnational development of enterprises, various branches of enterprises are spread all over the country, and more and more employees work outside. Enterprises need to provide mobile employees with convenient, fast, cost-effective Employees can conduct business exchanges and resource sharing with enterprises in a timely manner. At present, broadband access is becoming more and more common, and mobile users can easily access the local MAN and the Internet. Therefore, how to provide enterprise mobile users with PPP (Point-to-Point Protocol) broadband access on the WAN has become a demand . VPDN (Virtual Private Dial-up Network) service can well meet the dial-up demand of this wide area network. VPDN refers to a virtual private network comp...

AI Technical Summary

Problems solved by technology

[0005] 1. After the large message transmitted from the VPDN user to the LNS end server reaches the LAC, the LAC encapsulates the tunnel information to send the message to the tunnel. The encapsulated tunnel information includes the encapsulated IP packet header and the L2TP protocol packet header, but the The length of the IP packet that completes the tunnel information may exceed the MTU (Maximum Transmission Unit) of the tunnel, and fragmentation is required. This requires the peer LNS device to support the reassembly of IP fragmented packets, because fragmentation is for the outer layer IP packets. There is no original packet header information from the second fragment, and the LNS cannot find the server information based on the original packet header information after receiving this fragmented packet, so the LNS is required to reassemble all the fragmented packets, Then find the corresponding server information according to the original message header information, and finally transmit the message to the server, but some LNS devices do not support the reassembly of IP fragmented messages, and VPDN users cannot send large packets to the server at the LNS end

[0006] 2. After the large packet transmitted from the LNS end server to the VPDN user reaches the LNS, the LNS encapsulates the tunnel information and prepares to send the packet to the tunnel. However, it is found that the length of the IP packet that encapsulates the tunnel information may exceed the length of the tunnel. MTU requires fragmentation, which requires the peer LAC device to support the reassembly of IP fragmented packets, but some LAC devices do not support the reassembly of IP fragmented packets, and the LNS server cannot send large packets to VPDN users

[0009] The shortcoming of the first kind of scheme is: it will be very difficult to realize the recombination of IP fragment message by hardware, because the piece number that message is divided into is uncertain, and the arrival time of fragment message is uncertain, and fragment message has Possible loss, and the need for timers, these problems make it difficult for hardware to reassemble IP fragmented packets, which will consume a lot of hardware resources, manpower and material resources, and for devices with insufficient hardware resources, this solution will not be realized

[0010] The shortcoming of the second scheme is: due to the flexibility of software, it is not difficult to realize the reorganization of IP fragmented messages by software, but the speed of software is far behind that of hardware. The device is a bottleneck in terms of performance. When there are many users, it not only affects user forwarding, but may also affect existing users of the device.

Images