A hierarchical bandwidth manager for local area network outlets

In a local area network (LAN), the traffic types generated may vary from delay-sensitive video applications to delay-insensitive data packet delivery. Integration of applications with different QoS needs and traffic characteristics in a LAN has increased the demand to develop mechanisms able to manage such needs. A novel bandwidth regulation which is able to answer to such requirements is proposed. It is called the hierarchical bandwidth manager and is able to cope with best-effort and guaranteed flows so that bandwidth left unused by guaranteed flows is dynamically distributed among best-effort ones throughout the LAN. A tree representation of the LAN links is used by this mechanism. Regulation of link bandwidth is done in a hierarchical and distributed manner. The leaf nodes correspond to hosts and the others to gateways. Each node in the tree, other than the leaf nodes, respects an inter-node bandwidth share protocol. Leaf nodes conform to what we call intra-host regulation. Both concepts are defined in this paper. Intra-host regulation is implemented through a new mechanism that we call the fair shaper. An implementation of the fair shaper in a Solar 2.5 operating system and some experimental results are finally described