The Hot-swap Thecnology Of Distributed Three-tied Switch

The distributed three-tier switch is used in the convergence-level of large net, and backbone layer of small and medium net. Its position in net decid that it must get a high reliability. Hot-swap, which include hot backup and configuration recovery in software, is the main method to improve the reliability of distributed three-tier switch. Currently, under the hot-swap, all the distributed three-tier switches could backup only the user's configuration and system's status, but not the forward-tables information of switch produced due to running protocols. Once the configuration has been recovered, these information should be relearned, which prolong the interruption of traffic flow. What's more, in the process of configuration recovery, the sting-format configuration file is used to restore the configuration information. There are high coupling among blocks, and each block should be recovery in order. Also, the analyzing, sending and executing of orders are quite time-consuming, which lead to the low efficiency of configuration recovery.Hot-swap technology development and applications are reviewed firstly in this thesis. This thesis is describing the construction of the distributed three-tier switch, including both hardware and software. On such basis, this thesis continues to analyze the hot-swap principle of switch-boards and switch-cards, and the possible improvement of hardware in the fulfillment of the full hot backup about three-tier switch, and then provides a set of solutions to the above problem. As to the software, the thesis analyzes the principle and method of traditional configuration recovery, and finds out the key factor of restricting the recovery efficiency. It also provides several solutions, and adopts the method based on the binary configuration file after analysis and contrast, which realize the full hot-swap system, including the hot swap of interface-boards,main-boards and cards, which supports the full hot backup.There were two major features of full hot-swap system. The first one is that the backup of interface boards adapted the distributive restoring, which make the information produce according to the protocals backup, and reache the real hot backup that it reduce the time of discontinuous flow; The second one is that adopting the binary format configuration file to restore the configuration values, taking modules as basic management units of configuration recovery and taking features as basic storage units of configuration file could remove the coupling between modules. In the process of recovery, all the blocks are recuperated at the same time, which largely improve the efficiency and capability of hot-swap.Finally, with the distributed three-tier switch S9500E and the comware network platform, the full hot-swap system is fully tested on the functions and capabilitys. Test results show that the configuration recovery efficiency of this method is 7 to 9 times as that of traditional methods. Under the atmosphere of high traffic flow and high electromagnetic environment, the system can correctly finish the hot-swap of interface-boards,main-boards and cards, and can keep the order when more than three interface-boards are swapped simultaneously. Currently, the system is successfully applied in the distributive communication network products.