Quantcast
Industry Cortex

Document Brief

Performance of the Rapid Spanning Tree Protocol in Ring Network Topology...

Michael Pustylnik, Mira Zafirovic-Vukotic, Roger Moore, RuggedCom, Inc....

1. Introduction...

Mission critical industrial automation applications require a robust communications network that can recover quickly from cable and equipment failures. The use of Ethernet and IP based fieldbus protocols is growing rapidly and users are gaining confidence. Modbus-TCP, Profinet, Ethenet/IP, DeviceNet, IEC 61850, DNP, and IEC 60870-5-104 are just some of the protocols being used today to interconnect programmable logic controllers (PLCs), intelligent electronic devices (IEDs), and sensors to each other and to central control computers. Applications ranging from motion control, process control, discrete manufacturing, and the electrical utility SmartGrid have one need in common ensure high availability of the Ethernet network....

There are several approaches to providing high availability the ring based network topology is the simplest and most pervasive. There are numerous proprietary ring-based protocols available today from several vendors these methods do not interoperate with each other and lack the scrutiny of an open standard. The Rapid Spanning Tree Protocol as defined by IEEE 802.1D-2004 has equal if not better performance than such ring protocols and provides other benefits such as the ability to support any network topology. Unfortunately, most public information regarding RSTP performance is out of date and misleading as it is based on older version of RSTP. This paper will provide an in depth analysis of RSTP performance along with simple equations for estimating network failover and recovery times so that informed decisions can be made about its efficacy for a given industrial network application. For a ring of twenty switches, worse case failover times on the order of 100 milliseconds is quite realistic which makes RSTP effective for all but the most demanding of applications....

2. RSTP Operation IEEE 802.1D-2004...

2.1 Background...

Ethernet switches operate by storing and forwarding traffic between their ports. The switch examines each Ethernet frame and records the MAC source address and the port on which it resides. Subsequently, when a frame arrives for a given MAC destination address, the switch knows on which outgoing port to send the frame. If a frame arrives and its destination MAC address is unknown or is a multicast address, the switch will flood the frame out all of its por...

Document Keywords

Rapid Spanning Tree Protocol Performance of the Rapid Spanning Tree Protocol in Ring Network Topology pdfs white papers performance of rapid spanning tree protocol in ring network topology

About RUGGEDCOM INC

Contact

8474265606

sponsored links