Abstract: A method of determining whether to set up a delay-sensitive communication session over an internet protocol (IP) based network includes sharing link state information among the network nodes of the link state protocol controlled network, receiving an IP packet that conveys a request to set up a delay-sensitive communication session over the network; determining, based on the shared link state information, a shortest path through the link state protocol controlled network for the requested delay-sensitive communication session and whether the shortest path is deemed suitable for the delay-sensitive communication session, and setting up the delay-sensitive communication session over the shortest path only when the shortest path is deemed suitable for the delay-sensitive communication session.

Abstract: A communications network for a metropolitan area is disclosed. The network is comprised of three basic types of nodes: an access multiplexer, a photonic switch, and a core node. The access multiplexer provides multiplexing of data packets from end-users onto at least one sparse wavelength division multiplexed (SWDM) wavelength. The SWDM wavelengths are carried over fiber cable to the photonic switches, which consolidate these wavelengths into dense wavelength division multiplexed (DWDM) wavelengths for transmission to the core node. The core nodes include a photonic switch (PSX) and a service-aware terabit router core for routing packets within the metropolitan area via the network or out to a long haul network. The photonic switches and core nodes are capable of switching at the wavelength, group of wavelength, and fiber levels.

Abstract: A wavelength access server (WAS) architecture provides aggregation of traffic streams of diverse data communication protocols as well as provision of wavelength resources in an optical transport network. The WAS provides functions such as service traffic adaptation, traffic aggregation and segmentation, traffic classification, optical inter-working and system management. In particular, system management includes aspects such as signaling, connection management, resource co-ordination, protection prioritization and access policy management.

Abstract: A technique for adaptively distributing a web server request in a system having a plurality of web servers is disclosed. In one embodiment, the technique is realized by first generating a web server request distribution function for each of the plurality of web servers based upon performance measures of each of the plurality of web servers, wherein each of the plurality of web servers is assigned a respective probability range based upon each respective web server request distribution function. A random probability number is then generated for a web server request. The particular probability range encompassing the random probability number is then determined so as to identify the corresponding web server to which the web server request is to be distributed.

Abstract: A technique for providing a control and management protocol for an Ethernet network in an Ethernet layer is disclosed. In one embodiment, the technique is realized by transporting a plurality of inter-nodal messages via Ethernet packets based on a type parameter; identifying at least one management packet from the Ethernet packets; and identifying a management function associated with the at least one management packet based on a management parameter. In addition, the management function may involve notification of physical link failure; monitoring congestion; monitoring packet errors; communicating with an External Management System; measuring signal quality of link; detecting loss of signal; assessing signal quality of nodes by a loop back packet comparison; and communicating user information in the form of voice, data, and video between nodes.

Abstract: A system and method for synchronizing a local clock to a reference clock using a linear model of the error between the local clock and the reference clock is disclosed. In one embodiment, a direct smoothing process is used in conjunction with the linear model to estimate a frequency offset by which the frequency of an oscillator of the local clock is adjusted. Also disclosed herein is a phased-lock loop (PLL) adapted to synchronize a local clock with a reference clock using the direct smoothing process, as well as a system implementing the PLL for timing the playout of data received from a transmitter.

Abstract: A technique for establishing automatic service connectivity in a network between multiple network elements is disclosed. Each network element utilizes routing and distribution protocols to discover its neighbors and establish a topology. Optical fibers connect the network elements. Each optical fiber carries multiple wavelengths of signals, wherein the network elements communicate with a server. The method comprises: storing information pertaining to each of the network elements at the server; registering network elements by collecting information about each network element; receiving a connectivity request from a first registered node for connection with a second registered node; determining compatibility of the first and second registered node; and instructing network elements upon verifying compatibility to search for an end-to-end wavelength path and establish a connection between the first registered node and the second registered node.

Abstract: A technique for synchronizing clocks in a network is disclosed. In one exemplary embodiment, the technique may be realized as a method for synchronizing clocks in a network. The method comprises receiving a first timestamp and a second timestamp, each indicating a respective time instance as determined by a first clock signal within the network. The method also comprises measuring a first time interval between the first timestamp and the second timestamp. The method further comprises generating a difference signal representing a difference between the first time interval and a second time interval, and generating a second clock signal based upon the difference signal such that the second clock signal is synchronized with the first clock signal.

Abstract: A system and method for synchronizing a local clock to a reference clock using a linear model of the clock error between the local clock and the reference clock is disclosed. In one embodiment, a double-exponential smoothing process is used in conjunction with the linear model to estimate a frequency offset by which the frequency of an oscillator of the local clock is adjusted. Also disclosed herein is a phased-lock loop (PLL) adapted to synchronize a local clock with a reference clock using the double-exponential smoothing process, as well as a system implementing the PLL for timing the playout of data received from a transmitter.

Abstract: In a packet-switched network having a plurality of nodes interconnected by links, pre-defined protection paths provide protection of a selected plurality of links. Adjacent nodes connected by a protected link are adapted to detect a failure of the protected link, to encapsulate packets within tunnel packets, to differentiate between tunnel packets and non-tunnel packets and to exchange the tunnel packets via a protection path rather than via the failed link. This results in faster automatic protection switching of packet-based traffic. The invention is particularly suited to an Internet Protocol network.

Abstract: A wavelength access server (WAS) architecture provides aggregation of traffic streams of diverse data communication protocols as well as provision of wavelength resources in an optical transport network. The WAS provides functions such as service traffic adaptation, traffic aggregation and segmentation, traffic classification, optical inter-working and system management. In particular, system management includes aspects such as signaling, connection management, resource co-ordination, protection prioritization and access policy management.

Abstract: A technique for synchronizing clocks in a network is disclosed. In one exemplary embodiment, the technique may be realized as a method for synchronizing clocks in a network. The method comprises receiving a first timestamp and a second timestamp, each indicating a respective time instance as determined by a first clock signal within the network. The method also comprises measuring a first time interval between the first timestamp and the second timestamp. The method further comprises generating a difference signal representing a difference between the first time interval and a second time interval, and generating a second clock signal based upon the difference signal such that the second clock signal is synchronized with the first clock signal.

Abstract: A communications network for a metropolitan area is disclosed. The network is comprised of three basic types of nodes: an access multiplexer, a photonic switch, and a core node. The access multiplexer provides multiplexing of data packets from end-users onto at least one sparse wavelength division multiplexed (SWDM) wavelength. The SWDM wavelengths are carried over fiber cable to the photonic switches, which consolidate these wavelengths into dense wavelength division multiplexed (DWDM) wavelengths for transmission to the core node. The core nodes include a photonic switch (PSX) and a service-aware terabit router core for routing packets within the metropolitan area via the network or out to a long haul network. The photonic switches and core nodes are capable of switching at the wavelength, group of wavelength, and fiber levels.