Optimization Of Label Distribution Protocol Based On Laser Inter Satellite Link

With the development of communication technology,satellite communication based on laser inter satellite link is getting more and more attention.The laser-based inter satellite link makes up for the deficiency of traditional microwave technology in satellite communication by using laser communication and improves the on-board data exchange capability through large-scale networking.Because tag switching technology can effectively improve networking capability and support traffic engineering,it is of practical significance to construct tag distribution system in satellite optical network environment.This paper analyzes the characteristics of inter satellite network and studies the application of label distribution protocol in satellite optical network.The core module of the Label distribution system is signaling protocol.It is responsible for establishing and deleting LSP(Label Switched Path)and generating Label forwarding tables to improve the data forwarding rate.In signaling protocols,CR-LDP(Constraint-based Routing Label Distribution Protocol)supports traffic engineering by displaying parameters such as route and bandwidth in addition to establishing and deleting LSP.Therefore,CR-LDP was selected as the signaling protocol.Based on the characteristics of satellite optical network,this paper designed a label distribution system and studied the message processing process and controllability of CR-LDP.The main work is as follows:1)Based on the study of the working mechanism of CR-LDP,CR-LDP is divided into LSP establishment module,LSP deletion module,fault handling module,timing module and message processing module.In addition,if unidirectional links may occur in the inter-satellite environment,CR-LDP can add a common header to LDP messages without using TCP to transmit LDP messages to establish an LSP on unidirectional links.2)Based on the study of CR-LDP fast re-routing mechanism,a fast reconstruction mechanism was proposed to solve the problem that fast re-routing would occupy additional link bandwidth and could not stabilize the protected link.By directly rebuilding LSP on both ends of the interrupted link,the PACKET loss rate is reduced and network resources are saved.3)Add a lifetime TLV for LSP so that LSP can be automatically deleted without sending label release requests after service data is transferred.This reduces the operation burden on the management center and simplifies the LSP deletion process.The protocol code is implemented in the Vxworks operating system,and the innovation and applicability of the design content are verified through software and hardware tests.This paper provides some analysis and reference for the future large-scale laser inter satellite link networking.