Multicast and quality of service provisioning in parallel shared memory switches

Growing demand for differentiated services and the proliferation of Internet multimedia applications requires not only faster switches/routers, but also the inclusion of guaranteed qualities of service (QoSs) and support for multicast traffic. Here, the authors introduce a parallel shared memory (PSM) architecture that addresses these demands by offering both QoS guarantees and support for multicast traffic. It is well known that PSM architectures represent an effective approach for distributing the high-memory bandwidth requirement found in output-queued (OQ) switches, while maintaining their desirable performance attributes. At the core of the PSM architecture is a memory management algorithm that determines, for each arriving packet, the memory unit in which it will be placed. The PSM architecture discussed should be considered with the context of fabric on a chip in mind, where an implementation is conceivable on a single chip, providing a plug-in emulated OQ switching solution. A description and detailed analysis of an efficient memory management algorithm that supports QoS and multicast traffic is given with a discussion of hardware implementation considerations that highlight the PSM architecture's scalability and performance attributes.