Resilient Packet Ring

Optimized transport of data traffic over optical fiber ring

Overview

VisualSim Resilient Packet Ring (RPR) is a template and representative implementation of the IEEE 802.17. This is a standard designed for the optimized transport of data traffic over optical fibre ring networks. The library can be used in conjunction with the traffic and the model construction components to assemble a full system. The library has an implementation of complex system with plug-n-play reference for difference types of devices. The model can be used to compute packet latency, and effective throughput. The library enables the transmission of packets and can be integrated with the Ethernet and other protocol standard library in VisualSim. The model template is completely open for the designers to study the RPR network or update the protocol for future requirements.

Parameters Used

  • Data_Rate: This parameter is used to specify the rate at which data packets are sent
  • RPR_Stations: This block is used to send the required traffic
  • CoS: This parameter is used to specify the class they belong (whether class A, B or C)

Features

VisualSim RPR provides a dual counter rotating rings, nodes or stations, and Media Access Control protocol (MAC) messages to direct the traffic. The designer can modify the pre-built fairness algorithm with their own implementation by replacing the arbitration block in the template. This can be used to evaluate the traffic flow improvement and the elimination of congestions in the traffic scenarios.

  • MAC protocol directs the traffic
  • Two techniques called steering and wrapping is used
  • Spatial reuse
  • Supports the use of learning bridges

In General

An important trend in networking is the migration of packet-based technologies from Local Area Networks to Metropolitan Area Networks (MANs). The rapidly increasing volume of data traffic in metro networks is challenging the capacity limits of existing transport infrastructures based on circuit-oriented technologies like SONET and ATM. Inefficiencies associated with carrying increasing quantities of data traffic over voiceoptimized circuit-switched networks makes it difficult to provision new services and increases the cost of building additional capacity beyond the limits of most carriers’ capital expense budgets. Packet-based transport technology is considered by many to be the only alternative for scaling metro networks to meet the demand.

SONET does take advantage of the ring topology but does not handle data traffic efficiently, wasting ring bandwidth. Ethernet, while a natural fit for data traffic, is in fact difficult to implement on a ring and does not make the most of the ring’s capabilities. Resilient Packet Ring is an emerging network architecture and technology designed to meet the requirements of a packet-based metropolitan area network. In the past few years there have been fibre ring deployments in most metro areas. The challenge for service providers is to tap into the latent capacity available on these fibre rings and carve out as many profitable, revenue generating services as possible. This problem of effectively managing a shared resource (in this case the fibre ring is the resource that needs to be shared across thousands of subscribers in a metro area) is most efficiently solved at the MAC layer of the protocol stack.