| With the development of network technology,time-sensitive traffics continue to emerge,such as industrial Internet,AR/VR,autonomous driving,telemedicine,etc.These traffics have very strict requirements on the bandwidth,delay,and jitter of the transmission path.However,traditional IP networks adopt the "best effort" routing and packet forwarding method,which face huge challenges in dealing with the requirements of deterministic latency and ultra-low jitter.In particular,traditional networks generally adopt mechanisms such as time-out retransmission to ensure reliable transmission of traffics.Nevertheless,the fault detection and packet retransmission will introduce a large amount of extra delay,which seriously affects the transmission performance of time-sensitive traffics.Therefore,it is urgent to explore networking technologies to ensure the reliable transmission of timesensitive traffics.Based on the theory of temporal graph,this thesis proposes a time deterministic multi-path algorithm and protocol to improve end-to-end reliability and guaranteed delay of time-sensitive traffics in large-scale networks.The main work and innovation points are summarized as follows.This thesis summarizes the development status of key technologies for time deterministic networks,and analyzes the main reasons of the inability of the existing networks to guarantee the delay of traffics.A time-slotted graph model is introduced,which provides support for the construction of time-guaranteed routing through the joint representation of link transmission resources,storage resources,and time resources.Multiple queue scheduling mechanisms with guaranteed-delay capabilities are summarized,and the delay guarantee performance of several queue scheduling mechanisms is analyzed.A variety of multi-path routing algorithms and protocols are also explored,which provides a basis for the design of time deterministic network multi-path routing algorithm and protocol proposed in this thesis.Aiming at the problem that the time-varying characteristics of network resources and the randomness of traffic arrivals make it difficult to construct time deterministic routing,a time-slotted graph model(Q-TEG)is proposed to accurately characterize the multidimensional network resources in different time slots such as contact topology,link bandwidth and queue storage,providing model support for the construction of delayguaranteed routing.With Q-TEG,a time deterministic multi-path routing algorithm(QTEG-TDMPR)is proposed,which can efficiently find two transmission paths that meet the delay requirements by comprehensively considering the various Qo S constraints affecting the traffic delay in the network.Both paths have time attributes and are resource disjoint,which can effectively avoid network congestion,improve the reliability of end-to-end communication,and guarantee the deterministic latency.Simulation results show that,compared with the single-path retransmission strategy,the reliable guarantee mechanism based on multiple-path transmission can improve the single-hop delay performance by more than 20%.In view of the lack of time deterministic protocols and insufficient network layer service protection mechanisms in current large-scale networks,a multi-path time deterministic protocol(MPTD)is designed based on the traditional OSPFv3 and SRv6.The specific innovations are as follows.A new type of LSA is designed to characterize the network topology during different time slots,which can provide the required topology information for the Q-TEG-TDMPR algorithm.Two new types of SIDs,i.e.,MP.R and MP.E,are designed for duplicating and eliminating data packets to provide reliability guarantee for traffic transmission.The MP.T type SID is designed to accurately guide the data packets to be forwarded according to the time-slot information at each node to provide time deterministic guarantee.A physical simulation and verification platform of the MPTD protocol is built to verify the delay and reliability guarantee performance of the proposed protocol. |
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