Research On QoS-based Resource Isolation Technology For Virtual Link

Due to the deficiency of current Internet architecture, the network virtualization technology has become a main development direction in the future network architectures, as well as one research hot. The implement of network virtualization technology depends on the router virtualization technology, where the resource isolation technology for virtual link plays a more important role. We can use QoS to achieve the resource isolation technology for virtual link, because the design goal of QoS is to allocate the corresponding bandwidth resources for each flow. Thus, the main research content is QoS-based resource isolation technology for virtual link.By researching on the above mentioned technology, we propose a parallel QoS mechanism to support for the resource isolation among virtual links. Routers always adopt multi-core network processor to accelerate packet processing speed, so the proposed QoS mechanism is an optimization for this situation. And the parallel QoS mechanism runs on a special structure including one control-core and multiple forwarding-cores in parallel, which can effectively allocate and isolate the bandwidth resource for virtual links, guarantee the QoS requirement among all virtual links, and run on multi-core network processor with a higher efficiency. It’s able to effectively allocate and isolate resource between virtual-links, and to guarantee the common QoS requirement within each virtual-link, while efficiently executing on multi-core network processor. This paper puts forward two algorithms to support for the proposed mechanism: the token bucket algorithm based on multi-queue in the QoS ingress and the queue algorithm based on priority-extension in the QoS egress.The token bucket algorithm based on multi-queue adopts a series of improvement and innovation technologies based on the traditional token bucket algorithm. With the network processors adopted in router design, the traditional token bucket algorithm may cause resource access conflict when several cores access to the critical resources at the same time, which has to use the lock mechanism to ensure the critical resource access sequence. Doing this way will reduce the forwarding performance and the resource utilization. Thus, the performance of the mechanism is limited, and the processor utilization is reduced. The proposed algorithm in this paper that adopts the centralized management for the token generation and the distributed queue for token resource can distribute the token resource among different forwarding cores to reduce the probability of resource access conflict. Therefore, it can attain high packet forwarding performance while ensuring the resource isolation among virtual links.The queue algorithm based on priority-extension mainly aims at improving the traditional 8-priority queue algorithm. Due to the limited priority levels of traditional queue algorithm, it has to introduce the two-layer idea for the 8-priority queue algorithm to offer promises both for the resource isolation and for QoS requirement. However, this two-layer structure can cause the complication of queue algorithm, limited priority levels, and low system efficiency. The improved algorithm can extend more priority levels, not only 8 priority levels, which only has one layer for the queue structure. And, it can halved the number of priority level by and schedule the queues once, whiling ensuring the resource isolation and saving the system memory and processor resource.