Network Clock Synchronization Based On Delay And Ringed Topology

To measure the network performance between end and end, some metrics are really important, such as one-way delay. However, it is difficult to meausre this metric due to the asynchronism among hosts. This dissertation designed and worked out a network clock synchronization which is based on one-way delay measurement and ringed topology. In detail, it collects the time stamp data on hosts which are organize in logically ringed topology, then establishs the clock synchronious model base on the time stamp data, and finially makes all the hosts coorperate with each other to optimize the synchronious model data.Firstly, the research on the establishment of clock synchronous model is based on the present clock synchronous meathod made by Paxson, Moon, Li Zhang and some other person. After some improvement design, this dissertation present A&V synchronous meathod which can provide synchronized time stamps with better precision for the hosts.Secondly, the synchronization based on ringed topology is designed, which is totually different from the present meathod based on the tree, star or P2P model. Benefit from this logically topology, the system can get the inherit synchronous error which can help the host to improve the precision.Thirdly, the synchronous systom provide the dynamic maintenance for its logically topology, such as establishment, dismission, insertion and etc. It means that this system can be established or dismissed by itself within a short time. Another thing to mention is its self-maintenance ability, that is the ability for the other host to join into the established synchronous ring, or for the host which is already in the synchronous ring but who want to leave. In addition, it can passively withdraw the host which cannot be contacted for a long time.All in all, this system can synchronize several hosts in a logically ring topology, and provide the precise time stamp data to measure the one-way delay between hosts.