Spatial Reuse Protocol

Abstract: A data communications device that can operate in accordance with two or more protocols having different data formats and error-protection schemes. The protocol-dependent aspects of the device are handled by a peripheral portion of the device, allowing a substantially protocol-independent core portion that is insulated from protocol changes. Translation and/or adaptation mechanisms in the peripheral portion of the device allow the device to handle changes in data format and/or pipeline changes such as error protection without affecting the core portion of the device. A device and method are provided for inter-operating with both the Spatial Reuse Protocol (SRP) and the Resilient Packet Ring (RPR) architectures.

Abstract: Based on queuing theory, we develop an analytical approximation for low and high priority packet delays in a spatial reuse protocol (SRP) ring. SRP is a MAC layer protocol for ring based media (e.g., optical rings) that can carry IP and ATM client (prioritized) traffic (see Tsiang, D. and Suwala, G., "The Cisco SRP MAC Layer Protocol", RFC 2892, 2000). This protocol is one basis for the evolution of the currently standardized resilient packet ring, IEEE 802.17 (see http://www.ieee802.org/rprsg/). We develop approximative formulae for the transfer delay on a SRP ring and determine the maximum network throughputs for a traffic pattern. The formulae are instrumental in performance considerations and in quasi-validations of simulators.

Abstract: In this paper the all-terminal reliability and the two-terminal reliability models of rings using the Spatial Reuse Protocol (SRP) are developed. Moreover the interconnection of SRP-rings is considered. 1 I n t r o d u c t i o n The Spatial Reuse Protocol (SRP) has recently been introduced as a MAC layer protocol for ring based media [1, 2]. The protocol carries both IP and ATM client traffic and supports ring network redundancy similar to bidirectional self-healing rings (BSHRs) of SDH/SONET standards. Since each network element is subject to failures or disruptions, the network reliability is an important parameter for the employment of such a ring. This also emerges for today's IP networks [3], which may run over SRP. It should be noted that the major concern of reliability considerations is not motivated by the discard of packets at the SRP-buffers caused by network congestion, which are momentary effects (partly used for flow-control as in TCP) and should be negligible in a well dimensioned network. The overall network reliability can be used for the comparison of different design alternatives, e.g. between SRP-rings and rings operated with other protocols, or the dimensioning alternatives of rings in multiple-rings networks (e.g. size of ring-nodes). The reliability for an end-to-end connection also comes to front as a Quality of Service (QoS) parameter, which can be offered to customers (SRP-clients) or can be used for the QoS-routing in traffic engineered networks. The reliability models of SONET/SDH BSHRs have been determined in [4, 5]. The reliability models of SRP-rings differ from these, since SRP-rings interconnect hosts and allow for bypassing the hosts (e.g. during a host's software failure) in the "pass-thru mode" [1]. Thus the SRP nodes are organized differently in contrast to SONET/SDH nodes. In this paper we develop the reliability models of SRP-rings and moreover consider the interconnection of SRP-rings. It should be noted that the models are applicable both on repairable and non-repairable systems, where strictly speaking in former ones we deal with '~reliabilities" and in latter ones with "availabilities." 2 N e t w o r k M o d e l We describe a SRP-ring with n nodes by the network model in figure 1. A symmetric

Abstract: In this paper, we provide a comprehensive analysis of aggregated interference by opprtunistic radios accessing the white spaces of the digital television taking into account the “hidden node” problem. We propose a new statistical interference model for cognitive network in the white space context based on the amplitude aggregate interference, which accounts for the parameters related to the sensing procedure, spatial reuse protocol employed by secondary users, and environment dependent conditions like channel fading and signal obstructions. We derive the characteristic function and the nth cumulant of the cognitive network interference on the DTV receiver. Moreover, the proposed framework can help to understand secondary network interference in the TV white space context for successful coexistence between the licensed system and opportunistic networks.