Sycamore Networks, Inc.

Cascade Communications Corporation

John Thomas Moy

Tao Yang

Chikong Shue

Raymond Yinggang Xie

A system and a method for providing an emulated network including a plurality of emulated networking devices, in which a number of network node executable images are employed. Each of the network node executable images corresponds to one of the emulated networking devices. The emulated networking devices represent physical networking devices, such as optical switches. A portion of each of the network node executable images is operable to execute without modification on a physical networking device. Each of the network node executable images includes a number of program components, such as a topology related program component for maintaining a representation of the topology of the emulated network, a trunk manager program component for maintaining at least one emulated trunk between the corresponding emulated networking device and an adjacent other emulated networking device, and a circuit manager program component operable to maintain at least one emulated circuit between the corresponding emulated networking device and another one of the emulated networking devices. Various numbers of network node executable images may be executed on a single emulator machine, and multiple emulator machines may be employed to execute a single network node executable image.

Network emulator

A network comprises a plurality of switching nodes interconnected by communication links. The nodes transfer message packets thereamong over the communication links over paths defined through the nodes over the communication links. At least one of the nodes includes a communication link operational status determination element and an advertising message packet broadcast element. The communication link operational status determination element determines the operational status of the communication links, and the advertising message packet broadcast element broadcasts advertising message packets over the network including the operational status of the communication links. The other switching nodes in the network receive the advertising message packets and determine from the operational status identifier values whether to initiate a re-routing operation to re-route a path to avoid communication links which are malfunctioning. In a refinement, the one switching node further includes a communication link instance identifier and a communication link instance identifier control. The communication link instance identifier provides communication link instance values for the communication links connected to the switching node, and the communication link instance identifier control for controlling the communication link instance value provided by the communication link instance identifier in relation to the operational status determined by the communication link operational status determination element. The advertising message packet broadcast element further includes communication link instance values in the advertising message packets. The other switching nodes further determine from the communication link instance identifier whether to initiate a re-routing operation to re-route paths maintained thereby nodes to avoid the malfunctioning communication link.

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Acton, MA, United States of America

John Thomas Moy