摘要:
Algorithms and data structure are described for constructing and maintaining a clock distribution tree (“CDT”) for timing loop avoidance. The CDT algorithms and data structure allows a node to make an automated and unattended path switch to the most desirable clock source in the network. In response to a network topology change, a clock root node distributes new clock paths to all nodes in the network. In particular, the root node calculates a new clock path for each affected node by building a clock source topology tree, and identifying from that tree a path to the network node from a clock source of higher or equal stratum relative to that network node. The root node then sends a network message to each node indicating the new path that the node should use. Each node receives the message and compares the new path with the existing path. If the paths are different then the node acquires the new path just received in the message. If the paths are the same then the node does nothing and discards the message.
摘要:
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.
摘要:
A technique for routing data within an optical network having a plurality of network nodes is disclosed. In one embodiment, the technique is realized by receiving data at a first network node via a first optical signal having a first wavelength. The first wavelength corresponds to a first optical frequency, and the first optical frequency is mapped to a first binary representation. The first binary representation is divided into a first plurality of fields, wherein at least one of the first plurality of fields corresponds to a routing label in a first label stack. A top routing label in the first label stack indicates a second network node. Based at least partially upon the top routing label, the data is transmitted from the first network node to the second network node via a second optical signal having a second wavelength. The first wavelength may be either the same as or different from the second wavelength.
摘要:
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.
摘要:
A method and apparatus are provided for adjusting the volume of data communicated between a transmitter and a receiver on a network, in a time interval. The method involves producing a desired volume value in response to a volume value specified by the receiver and a difference between a target departure volume and an estimate of arrival volume of data at a queue through which data passes from the transmitter to the receiver, and communicating the desired volume value to the transmitter in response to an acknowledgement signal produced by the receiver.
摘要:
A technique for adaptively controlling a gain of an optical amplifier is disclosed. In one particular exemplary embodiment, the technique may be realized by a method comprising the steps of measuring an output power signal of the optical amplifier; computing a command signal from an input power signal; computing a model state signal of a reference model; computing a model output signal of the reference model based at least in part on the model state signal; computing an error signal between the model output signal and the output power signal of the optical amplifier; adjusting at least one adaptive control gain value to minimize the error signal; and computing a control input signal for driving the optical amplifier based at least in part on the at least one adaptive control gain value, the error signal, the model state signal and the command signal.
摘要:
A technique for wave-mixing bulk frequency conversion in a network comprising one or more channels is disclosed that enables cost-effective wavelength-conversion. In one particular exemplary embodiment, the technique may be realized by a new class of multi-log wave-mixing-cross-connects that are based on arbitrary b×b space-switching elements, where b>2. In such cross-connects, for any light-path, the worst case number of cascaded frequency-conversions is O(logb(FW)), F being the number of fibers. One benefit of the new design may be maximized when W=O(F), b=O(F), and the worst-case number of cascaded conversions is O(1).
摘要:
A method and apparatus for controlling a rate at which packets are transmitted to a network node having a queue and a network element employing same is described. The method and apparatus cooperate to generate a probability value in response to queue occupancy and desired queue occupancy and to control the packet in response to the probability value and a reference value to cause a source of the packet to change its transmission rate. Control of the packet is achieved by dropping the packet or by modifying the packet to include a message informing the source that it should adjust its transmission rate. In one embodiment, the probability value is converted into an inter-drop/mark value representing the number of packets to be admitted into the queue between dropped or marked packets.