Abstruet-The problem of allocating network resources to the users of an integrated services network is investigated in the context of rate-based flow control. The network is assumed to be a virtual circuiq comection-based packet network. We show that the use of Generalized processor Sharing (GPS), when combined with Leaky Bucket admission control, allows the network to make a wide range of worst-case performance guarantees on throughput and delay. The scheme is flexible in that d~erent users may be given widely different performance guarantees, and is efilcient in that each of the servers is work conserving. We present a practicat packet-by-packet service discipline, PGPS (first proposed by Deme5 Shenker, and Keshav [7] under the name of Weighted Fair Queueing), that closely approximates GPS. This altows us to relate ressdta for GPS to the packet-bypacket scheme in a precise manner. In this paper, the performance of a single-server GPS system is analyzed exactty from the standpoint of worst-case packet delay and burstiness when the sources are constrained by leaky buckets. The worst-case sewdon backlogs are also determined. In the sequel to this paper, these results are extended to arbitrary topology networks with multiple nodes. I.

Consider a switching component in a packet switching network, where messages from several incoming channels arrive and are routed to appropriate outgoing ports according to a service policy. One requirement in the design of such a system is to determine the buffer storage necessary at the input of each channel and the policy for serving these buffers which will prevent buffer overflow and the corresponding loss of messages. In this paper a class of buffer service policies, called Least Time to Reach Bound (LTRB), is introduced that guarantees no overflow, and for which the buffer size required at each input channel is independent of the number of channels and their relative speeds. Further, the storage requirement is only twice the maximal length of a message in all cases, and as a consequence the class is shown to be optimal in the sense that any nonoverflowing policy requires at least as much storage as LTRB. 1 Introduction We consider a system consisting of several input channels ...

A model of a switching component in a packet switching network is considered. Packets from several incoming channels arrive and must be routed to the appropriate outgoing port according to a service policy. A task confronting the designer of such a system is the selection of policy and the determination of the corresponding input buffer requirements which will prevent packet loss. One natural choice is the Longest Queue First discipline, and a tight bound on the size of the largest buffer required under this policy is obtained. The bound depends on the channel speeds and is logarithmic in the number of channels. As a consequence, Longest Queue First is shown to require less storage than Exhaustive Round Robin and First Come First Served in preventing packet overflow. This work was done while Z. Rosberg and M. Sidi were at the IBM T. J. Watson Research Center. 1 Introduction Technological advancements have brought about new switching fabrics that can support various types of traffi...

this paper, we present our approach in finding this worst case cell delay within an ATM switch. In terms of computation complexity, we find out that our proposed method is no harder than any other existing methods in finding such worse case delay. Furthermore, while other researchers tackle different schedulers with different approaches, our method is general enough and is applicable to schedulers that adopt the FIFO, Static Priority (SP), Earliest Deadline First (EDF) and Generalized Processor Sharing (GPS) scheduling policies. In addition, our proposed "Fixed Points" method can trade- off accuracy with computation complexity for performance improvement. As a result, our proposed method has shown to be superior to all existing methods in terms of computation complexity. Through our simulation experiments based on real-time MPEG video traffic, we arrived with the following observations: 1. If the deadlines are not greater than 0.2205 second, there is no significant improvement on the performances of connection admission control when more than 5 segments are used; 2. The fixed points computation method could efficiently reduce the computation complexity of the connection admission control by more than 50% with little performance loss; 3. Comparing to the FIFO Scheduler, the EDF scheduler has an advantage only in the region where traffic is less bursty and posses a wider range in deadlines

This paper describes a design of a high-speed packet switching system for integrated voice, video and data communications. The system makes use of a simplified network architecture in order to achieve the low packet delay and high nodal throughput necessary for the transport of voice and video. A prototype of this system has been implemented and is now being tested under a variety of packet traffic loads. We have demonstrated that this system provides a cost-effcctive solution for private integrated networks. KEY WORDS Integrated networks Packet switching Broadband ISDN Private networks

Traditional broadcast protocols are inappropriate for the high-speed networks of the future. Such protocols are limited by the speed of software pro-cessing, which becomes a bottleneck as network speeds increase. This paper presents a broadcast protocol that is appropriate for high-speed net-works, and is tolerant of failures involving the loss of messages. The protocol is based primarily on the simple hardware functions present in a high-speed net-work node. This leads to message delivery at hardware speeds. In the unlikely event of a fail-ure, some software intervention may be required to guarantee the timely termination of the pro-tocol. However this software processing does not interfere with message delivery. We show that in the likely cases, the protocol guarantees message delivery within D ~ time, where D is the diameter of the network, and ~ is the maximum link delay.