Asymmetric. Link Aggregation Switching Scheduling Algorithm

In recent years, link aggregation technology developed rapidly, and has been widely used in data communication fields. In the link aggregation, aggregate interface requires asymmetrical switch to provide the appropriate support. Therefore, the realization of asymmetric link aggregation switch has very important practical significance.Switching device with asymmetrical port speeds has been researched by many manufacturers and research institutions, including Cisco, Intel, Gigamon Systems LLC and ZTE. Many patents have been issued. In this thesis, asymmetric switch architecture and asymmetric switch scheduling algorithms are researched. First, the existing structure of the asymmetric switch architectures were summarized, so that an appropriate asymmetric switch architecture is selected for link aggregation, then many scheduling algorithms which are used in symmetric switch have been researched, such as PIM, RRM, iSLIP, iSLIP2, C_iSLIP2, PPVOQ and Polling, on this basis, two types of scheduling algorithms are proposed for asymmetric switch where all ports are fair or with priority.For asymmetric algorithms which all ports are fair, the core idea is to design mapping mechanisms and scheduling algorithms with the logical port supported. Mapping mechanism, which make all symmetry scheduling algorithms can been used for asymmetric switch, such as PIM, RRM, iSLIP, iSLIP2, C_iSLIP2, PPVOQ and Polling. The scheduling algorithms which support for logical port, we choose C_iSLIP2 algorithm with single iteration to alter its rotary table of Arbiter to schedule the logical port.For asymmetric algorithms which all ports are with priority, the core idea is to design port priority table. We choose iSLIP2 algorithm to use port priority table instead of its rotary table for mapping mechanisms and algorithms with logical port supported.Under the Bernoulli and self-similar flow, all scheduling algorithms which are supported asymmetric switch are simulated; the average queue delay and average queue length of VOQ queues are simulated and compared. The results showed that:logical C₁SLIP2 scheduling algorithm performed better than other scheduling algorithms in the condition of asymmetric switch which all ports are fair; Logic 3SLIP2 algorithm with priority performed better than other scheduling algorithms in the condition of asymmetric switch which all ports are with priority.