"Time-driven priority" flow control for real-time heterogeneous internetworking

Abstract

We consider real-time traffic in a heterogeneous internetworking environment with IP routers, MAC bridges, hubs, switched LANs etc. We assume that the current routing protocols remain unchanged. However in this environment, in order to provide quality of service (QoS): bandwidth, delay, constant-bounded jitter and no-loss due to congestion, we suggest a new flow control function called time-driven priority, which is an internal traffic shaping mechanism. We show how it supports two classes of connections: constant bit rate (CBR) with deterministic guarantees, and variable bit rate (VBR) with statistical multiplexing. The mechanism does not require to identify and separate the packet flows of different real-time sessions/connections inside the network. As a result, it achieves lower switching complexity when compared with other internal traffic shaping methods. As consequences of the time-driven priority mechanism we further achieve: (1) QoS parameters which are independent of the connection bandwidth, (2) QoS parameters which are independent of the existing heterogeneous internetworking asynchronous data traffic and (3) the capability for policing and securing the network QoS.