Abstract: An analyzer and method of analyzing a sample are provided. The method includes providing a sample on a substrate, and irradiating the sample with at least three incident beams of light. Each of the incident beams contains light of a different frequency, and the sample is substantially transmissive at each of the different frequencies. The method also includes providing a light sensing arrangement to receive light patterns from the incident beams that have passed through the substrate, and analyzing properties of the sample through identifying properties of the light patterns arising from diffraction of the light of the three incident beams by the sample. A difference in frequency between first and second ones of the incident beams is the same as a difference in frequency between second and third ones of the incident beams.

Abstract: The components of communication network device ingress systems and methods cooperate to manage information ingress and prevent denial of service attempts. A classifier classifies incoming information. A classification filter filters the information on a classification basis to prevent denial of service. The classification filter includes a classification filter counter for tracking the flow of information associated with the classification filter. A zero value in the classification filter counter indicates that a buffer capacity limit associated with the classification is reached. The counter permits information to flow to a packet buffer if the classification filter counter value is not zero and discards information if the classification filter counter value is zero. In one exemplary implementation the classification filter counter decrements a classification filter counter value when the information is placed in the buffer.

Abstract: The components of communication network device ingress systems and methods cooperate to manage information ingress and prevent denial of service attempts. A classifier classifies incoming information. A classification filter filters the information on a classification basis to prevent denial of service. The classification filter includes a classification filter counter for tracking the flow of information associated with the classification filter. A zero value in the classification filter counter indicates that a buffer capacity limit associated with the classification is reached. The counter permits information to flow to a packet buffer if the classification filter counter value is not zero and discards information if the classification filter counter value is zero. In one exemplary implementation the classification filter counter decrements a classification filter counter value when the information is placed in the buffer.

Abstract: The components of communication network device ingress systems and methods cooperate to manage information ingress and prevent denial of service attempts. A classifier classifies incoming information. A classification filter filters the information on a classification basis to prevent denial of service. The classification filter includes a classification filter counter for tracking the flow of information associated with the classification filter. A zero value in the classification filter counter indicates that a buffer capacity limit associated with the classification is reached. The counter permits information to flow to a packet buffer if the classification filter counter value is not zero and discards information if the classification filter counter value is zero. In one exemplary implementation the classification filter counter decrements a classification filter counter value when the information is placed in the buffer.

Abstract: The components of communication network device ingress systems and methods cooperate to manage information ingress and prevent denial of service attempts. A classifier classifies incoming information. A classification filter filters the information on a classification basis to prevent denial of service. The classification filter includes a classification filter counter for tracking the flow of information associated with the classification filter. A zero value in the classification filter counter indicates that a buffer capacity limit associated with the classification is reached. The counter permits information to flow to a packet buffer if the classification filter counter value is not zero and discards information if the classification filter counter value is zero. In one exemplary implementation the classification filter counter decrements a classification filter counter value when the information is placed in the buffer.

Abstract: An apparatus includes: a logic circuit with electronic memory to: monitor signal traffic with at least one client and a computer network to determine, without changing the signal traffic, for each client, a network address and a port to which that client is connected; provide to a first dynamic table the network address and port for each said client; access an authentication server that has a second table of user names and corresponding passwords for network login, in which the second table also includes for each user name and password a corresponding virtual local network (VLAN) membership and/or VLAN tag and/or Quality of Service (QoS); and add to the first dynamic table the user name, VLAN membership, VLAN tag and QoS information learnt from the authentication server in the second table.

Abstract: An apparatus includes: a logic circuit with electronic memory to: monitor signal traffic with at least one client and a computer network to determine, without changing the signal traffic, for each client, a network address and a port to which that client is connected; provide to a first dynamic table the network address and port for each said client; access an authentication server that has a second table of user names and corresponding passwords for network login, in which the second table also includes for each user name and password a corresponding virtual local network (VLAN) membership and/or VLAN tag and/or Quality of Service (QoS); and add to the first dynamic table the user name, VLAN membership, VLAN tag and QoS information learnt from the authentication server in the second table.

Abstract: A computer network including: at least one switch connecting at least one edge device to the remainder of the network, said at least one switch including: snooping apparatus using DHCP to monitor the signal traffic through the switch to or from the each edge device to determine, without changing the traffic signals, for each edge device, the MAC address, the IP address, and the port of the switch to which it is connected, and a dynamic table within said switch of, for each edge device, the MAC address, the IP address, and the port which it is connected, the contents of the table being provided by said snooping apparatus.

Abstract: A network unit for the reception and forwarding of data packets and for use in a stack of similar units includes a data processor and cascade control logic for the exchange of control frames with others of said units in the stack. The cascade control logic is operative to cooperate by means of the control frames in an automatic process for incrementally applying stack numbers to the units in the stack. The cascade control logic can retain a stack number in storage and the data processor is operative to execute a program to apply to the network unit and the other units progressive stack numbers which accommodate previously applied and retained stack numbers. The network unit can act as a master applying the program to the other units and as a slave whereupon it receives a stack number determined by another unit in the stack.

Abstract: A computer network including: at least one switch connecting at least one edge device to the remainder of the network, said at least one switch including: snooping apparatus using DHCP to monitor the signal traffic through the switch to or from the each edge device to determine, without changing the traffic signals, for each edge device, the MAC address, the IP address, and the port of the switch to which it is connected, and a dynamic table within said switch of, for each edge device, the MAC address, the IP address, and the port which it is connected, the contents of the table being provided by said snooping apparatus

Abstract: A computer network including: at least one switch connecting at least one edge device to the remainder of the network, said at least one switch including: snooping apparatus using DHCP to monitor the signal traffic through the switch to or from the each edge device to determine, without changing the traffic signals, for each edge device, the MAC address, the IP address, and the port of the switch to which it is connected, and a dynamic table within said switch of, for each edge device, the MAC address, the IP address, and the port which it is connected, the contents of the table being provided by said snooping apparatus.

Abstract: A computer network including: at least one switch connecting at least one edge device to the remainder of the network, said at least one switch including: snooping apparatus using DHCP to monitor the signal traffic through the switch to or from the each edge device to determine, without changing the traffic signals, for each edge device, the MAC address, the IP address, and the port of the switch to which it is connected, and a dynamic table within said switch of, for each edge device, the MAC address, the IP address, and the port which it is connected, the contents of the table being provided by said snooping apparatus

Abstract: A network unit for the reception and forwarding of data packets and for use in a stack of similar units includes a data processor and cascade control logic for the exchange of control frames with others of said units in the stack. The cascade control logic is operative to cooperate by means of the control frames in an automatic process for incrementally applying stack numbers to the units in the stack. The cascade control logic can retain a stack number in storage and the data processor is operative to execute a program to apply to the network unit and the other units progressive stack numbers which accommodate previously applied and retained stack numbers. The network unit can act as a master applying the program to the other units and as a slave whereupon it receives a stack number determined by another unit in the stack.

Abstract: A communication system comprises a plurality of interfaces disposed for sending data packets by way of virtual circuit connections and for receiving data packets by way of virtual circuit connections in an asynchronous transfer mode. The interfaces by means of the virtual circuit connections emulate at least one local area network including unit for establishing a virtual circuit connection functioning as a BUS (broadcast and unknown server) for the broadcast of data packets throughout the emulated local area network. An asynchronous transfer mode switch receives packets by way of virtual circuit connections from each of said the interfaces, replicates the packets and sends them to all the other interfaces, thus to establish a mesh between said interfaces. At least one interface comprises a unit for mapping virtual circuit connections between one interface and at least one terminal which is not directly connectable in the mesh connection into virtual circuit connections in the mesh.

Abstract: An address look-up data-base is used to store medial access control addresses for resolution into channel numbers in a system for transmitting data in an asynchronous transfer mode. Static random access memory is used to contain pointer tables, there being a pointer table for each possible priority level in the data packet. Thus a search for the media access control address of a data packet in the content addressable memory yields, among other data, a priority value which when combined with other data points to a location in one of the pointer tables, which accesses the appropriate channel number.

Abstract: Data received in the form of data packets which include destination addresses is transmitted over virtual channels in an asynchronous transfer mode to emulate the operation of a plurality of emulated local area networks. A plurality of bus channels are provided, each specified for the broadcast transmission of data packets to members of a respective one of the emulated local area networks. An address look-up data-base is used to receive the destination address of a data packet and data defining the respective bus channel for the broadcast transmission of that packet in the respective emulated local area network. The data packet is then transmitted over the respective bus channel. The content addressable memory provides a data field which indicates whether a request for the resolution of the destination address into a specific virtual channel number has been made.