An Optical Burst Reordering Model for Time-Based and Random Selection Assembly Strategies
Contention resolution schemes in Optical Burst Switched networks (OBS) as well as contention avoidance schemes delay burst delivery and change the burst arrival sequence. The burst arrival sequence usually changes the packet arrival sequence and degrades the upper layer protocols performance, e.g., the throughput of the Transmission Control Protocol (TCP). In this paper, the authors present and analyze a detailed burst reordering model for two widely applied burst assembly strategies: time-based and random selection. They apply the IETF reordering metrics and calculate explicitly three reordering metrics: the reordering ratio, the reordering extent metric and the TCP relevant metric. These metrics allow estimating the degree of reordering in a certain network scenario.