Cluster computer simulation of buffer sharing schemes under bursty traffic load

In this thesis it is first analyzed the effect that different Average Burst Length, buffer size or number of ports have on the performance in terms of packet loss ratio on shared memory network switches using Complete Sharing as baseline for the memory allocation scheme. Three different shared memory allocation schemes - Sharing with a Minimum Allocation (SMA), Sharing with Maximum Queue lengths (SMXQ), and Dynamic Threshold (DT) - are then analyzed under varied traffic conditions in order to determine the best configuration for each tested scenario. Having determined the best configuration for each individual scheme under all the tested scenarios, DT scheme is then compared against SMA scheme, as well as SMXQ scheme in order to determine which of the conventional shared memory allocation schemes presents a lower packet loss ratio on each tested scenario. A new shared memory allocation scheme referred to in this thesis as ‘Shortest Queue First’ (SQF) scheme is evaluated. SQF aims at decreasing packet loss ratio while maintaining fairness of memory utilization. This proposed scheme is subjected to the same traffic conditions as the other schemes mentioned above; a comparison is then drawn against the conventional scheme with the lowest packet loss ratio for each scenario in order to determine the extent to which packet loss ratio decreases for a switch utilizing the SQF scheme

Design and evaluation of high-performance packet switching schemes

The design of high-performance packet switches is essential to efficiently handle the exponential growth of data traffic in the next generation Internet. Shared-memory-based packet switches are known to provide the best possible delay-throughput performance and the lowest packet-loss rate compared with packet switches using other buffering strategies. However, scalability of shared-memory-based switching systems has been restricted by high memory bandwidth requirements, segregation of memory space and centralized control of switching functions that causes the switch performance to degrade as a shared-memory switch is grown in size. The new class of sliding-window based packet switches are known to overcome these problems associated with shared-memory switches. This thesis presents different schemes proposed earlier by Dr. Kumar for use in the sliding-window switch to allocate self-routing parameters. Comparative performance of these schemes have been evaluated in this thesis. The results show the scalability of the switch that can be achieved with different parameter assignment schemes. It is shown that not all assignment schemes have same performance. With appropriate assignment scheme, it is possible to achieve very high throughput-performance and switch size for sliding-window switches

Design and performance evaluation of switching architectures for high-speed Internet

The motivation for this thesis is the desire to build faster and scalable routers that efficiently handle the exponential traffic growth in the Internet. The Internet forwards information through a mesh of routers and switches, which has to keep up with the increasing demands of traffic. Shared-memory based switches are known to provide the best throughput-delay performance for a given memory size. In this thesis performance of commonly used memory-sharing schemes for the shared memory switches are evaluated under balanced and unbalanced bursty traffic. The scalability of shared-memory switches has been a research issue for quite sometime. One approach is to employ multiple memory modules and use them in parallel to enhance the capacity. The two well-known architectures in this category are (i) shared-multibuffer (SMB) switch architecture invented by Yamanaka et al. of Mitsubishi Electric Corporation, Japan; and (ii) the sliding-window (SW) switch architecture invented by Dr. Kumar of UTPA, Texas, USA. In this thesis, performance of these two architectures are evaluated and compared. Furthermore, in this thesis, the SW switch architecture is extended to enable priority switching to provide differentiated Quality of Service (QoS) for different traffic classes