Abstract: A method and apparatus for accessing resource objects contained in a distributed memory space in a communications network, including dividing the distributed memory space into a plurality of memory pools, each pool containing a collection of resource objects, providing a plurality of resource manager objects, each resource manager object having an associated set of memory pools and a registry of network unique identifiers for the resource objects in those pools, and accessing a given resource object via its network identifier. Another aspect of the invention is to provide a relativistic view of state of a plurality of objects, each object generating a state vector representing that object's view of its own state and the state of all other objects, each object sending its state vector to other objects, and each object maintaining a state matrix of the state vectors.

Abstract: A data buffering storage circuit automatically allocates a portion of shared storage area to the direction in which data buffering is required. This scheme allows use of fewer parts on a piece of networking hardware, which in turn lowers the cost, simplifies the design, and uses existing on-board memory in a more efficient manner. In at least one embodiment, a first area is allocated to the buffering of a first port of a network switch, a second memory area is allocated to the buffering of a second port of the network switch, and a third area is shared among the buffering of the first port and the buffering of the second port.

Abstract: An ATM scheduler in accord with the invention supports multiple transmission traffic types (e.g. CBR, VBR and ABR) for each of a plurality of virtual path connections (VPCs) on an ATM link. The scheduler maintains one or more scheduling tables defining the hierarchy of traffic types and the scheduling for each type of traffic within each virtual path. In each cell transmit time, one VPC is identified as assigned to the opportunity to transmit in the respective cell transmit time. Each virtual path connection supports at least one type of high priority traffic, such as constant bit rate (CBR) traffic, over a plurality of virtual circuit connections. The scheduler determines if there is a high priority service virtual circuit connection (VCC), from among those associated with the identified VPC, and that has been assigned the current cell time slot. If the scheduling device identifies such a VCC, then the scheduler provides the transmit opportunity for that VCC.

Abstract: Apparatus and method for distributed object filtering of objects transferred between a client and server. The objects may be alarms transferred between a network management server and one or more network management applications. The apparatus and method further includes applying a plurality of policy-based filters to the alarms. The filters may be named and stored in a database, and application of the policy-based filters may be scheduled for different times. The same policy-based filters may be applied to one or more multiple network management applications. The system and method provides increased performance and reliability of passing objects from a server to a client application.

Abstract: Apparatus and method wherein multiple router interfaces are assigned the same IP network address, creating an IP work group. This enhances host mobility by allowing, in one embodiment, a host to be relocated anywhere in the work group without requiring reconfiguration of the host. As a further option, host address ranges may be specified (i.e., locked) to designated interfaces of the work group, to enhance security by restricting the allowed host mobility within the work group. An additional advantage is a reduced consumption of network and subnet addresses, because now a single address is used for several physical networks.

Abstract: Apparatus and method for monitoring parameters that govern the operational characteristics of a network device, including the use of templates for generating configuration records of network devices of a selected model type. A database of models is provided, each model representing an associated network device and including attribute values for the parameters of the associated network device. Templates are used to screen a model in order to retrieve values for each of the attributes and create a configuration record. The configuration records may be stored in the configuration manager or other storage device, and/or transferred to the pre-existing model database for use by a network management system in reconfiguring the associated network devices. Additionally, a method and apparatus is provided that defines network groups, defines network policies for groups, determines conflicts, and resolves conflicts among groups and devices.

Abstract: A method and apparatus for accessing resource objects contained in a distributed memory space in a communications network, including dividing the distributed memory space into a plurality of memory pools, each pool containing a collection of resource objects, providing a plurality of resource manager objects, each resource manager object having an associated set of memory pools and a registry of network unique identifiers for the resource objects in those pools, and accessing a given resource object via its network identifier. Another aspect of the invention is to provide a relativistic view of state of a plurality of objects, each object generating a state vector representing that object's view of its own state and the state of all other objects, each object sending its state vector to other objects, and each object maintaining a state matrix of the state vectors.

Abstract: A message transfer arrangement includes a client node and a server node interconnected by a data link. The client node sequentially receives requests from user applications and generates, in response to each request, command messages for transmission by said interface, each command message including a command and having a transmit slot identifier identifying the request in the sequence of requests received by said request receiver and a transmit sequence identifier identifying the command message in the sequence of command messages relating to the request. The selection of whether to transmit a command message related to one request or to a subsequent request is based on a received slot identifier and a received sequence identifier in a response message. The server node receives command messages from, and transmits response messages to, the client node over the data link.

Abstract: An ATM switch supporting multicast transmissions and efficient transmission of frames. A cell is received on a multicast connection and transmitted on several branches/ports. Instead of copying a multicast cell several times for each output branch, only one copy of each multicast cell is maintained. The cell order and the stored cell data form a physical queue. Several logical queues are maintained, one for each output branch. In one embodiment, linked lists are used to maintain the queues. A cell in the physical queue is deleted after all logical queues traverse that cell. A shared tail pointer is used for all the logical queues to minimize additional processing and memory requirements due to the usage of logical queues. The queues enable cells forming a frame to be buffered until the end of frame cell is received, which provides for efficient handling of frames.

Abstract: A network system includes a hierarchical directory which includes a plurality of nodes in a tree structure. Each node contains a set of address mappings relating a first address to a second address. An address resolution request attempts to resolve a first address to a target address in a node in which the first address is located. If the resolution of this first address cannot be accomplished in this first node, the process moves to a next higher node in the hierarchy and again attempts to resolve the request. The address mappings become less specific as the process moves up the hierarchy and, as a result, more general addresses will be used to resolve the first address to the target address.

Abstract: Network capacity evaluation and planning is performed based upon the traffic across the links of the network. Once a link's traffic volume has been measured, it is compared with the link's traffic capability, and the resulting parameters compared with the traffic and capability of other links of the network to create measures of network capacity and balance. Then, simulated changes to the network configuration may be made by substituting simulated traffic volume amounts and capabilities for selected link traffic measurements and capabilities, and the resulting measures of network capacity and balance may then be compared to determine whether the simulated changes represent a preferred network configuration.

Abstract: A multi-domain network manager provides alarm correlation among a plurality of domains included in a communications network. Individual network management systems each monitor a single respective domain of the communications network, and provide intra-domain alarms indicative of status specific to the single respective domain. The multi-domain network manager receives the intra-domain alarms, and correlates them to provide inter-domain alarms as well as responses in the form of corrective actions. The multi-domain network manager thus provides a high level of correlation and response for the entire network while each network management system provides a lower level of correlation and response for an individual domain of the network.

Abstract: A multi-protocol packet translator is disclosed. The translator may have microcoded control to translate a packet from one protocol to another. The microcoded instructions may be fed through a pipeline to control reading of information from information sources (including the original packet) and selectively connecting those sources to an output memory.

Abstract: Method and apparatus for fault management of computer networks which utilizes a proxy or recruit network device to test the responsiveness of a network device. When a first network device loses contact with a second network device, the first network device uses a proxy network device to determine if the second network device can be reached and reports back to the first network device whether the contact attempt was successful. The proxy network device may contact the second network device through a different path and/or protocol than used by the first network device.

Abstract: An input-buffered multipoint switch having input channels and output channels includes multilevel request buffers, a data path multiplexer, and a scheduler. The switch has a distinct multilevel request buffer associated with each input channel and each request buffer has multiple request registers of a different request buffer priority. The request registers store data cell transfer requests that have been assigned quality of service (QoS) priorities, where the QoS priorities are related to packet source, destination, and/or application type. The multilevel request registers are linked in parallel to the scheduler to allow arbitration among requests of different input channels and different request buffer priority levels. The preferred arbitration process involves generating QoS priority-specific masks that reflect the output channels required by higher QoS priority requests and arbitrating among requests of the same QoS priority in QoS priority-specific multilevel schedulers.

Abstract: A scheduler in accord with the invention schedules available bit rate (ABR) traffic over an asynchronous transfer mode (ATM) link in such a manner as to provide circuits having the ABR traffic service a minimum cell rate (MCR) that may be greater than zero. The scheduler uses static scheduling information to schedule traffic for high priority services, such as constant bit rate service. The static information also specifies transmit opportunities for an ABR circuit, in a manner analogous to that for CBR traffic. The statically scheduled transmit opportunities provide a negotiated minimum cell rate that is greater than zero, for the ABR circuit. The scheduler maintains dynamic scheduling information, which it uses to schedule traffic in otherwise available transmit times. For example, the scheduler may use the dynamic information to create a work list of virtual circuit connections for ABR service. During any cell transmit time that is not used by a higher priority service (e.g.

Abstract: A method and apparatus for supplying new requests to a scheduler in an input-buffered multiport switch involve selecting a request that does not target output channels that conflict with output channels targeted by requests that are already accessible to the scheduler. Specifically, target output channels of requests that are presently accessible to the scheduler are identified and compared to target output channels of requests that are included in a queue of next-in-line requests. The queue of next-in-line requests is reviewed and the highest priority request having no conflicting output channels is supplied to the scheduler. By supplying the scheduler with a new request that targets non-conflicting output channels, the scheduler is presented with a wider range of requested output channels from which to choose in each arbitration cycle. In a first embodiment, one, two, or eight ports are connected to each one of four input/output controllers in a switch having a four-channel switch fabric.

Abstract: A method for improving modal bandwidth in computer networks using multimode optical fiber and single mode sources is disclosed in which the optical signal from a center of the optical fiber is blocked from reaching detector. This is accomplished according to a number of different techniques including the use of opaque spots on the fiber media/fiber couplers or the use of dark-cored fiber couplers. These configurations prevent pulse splitting that occurs in single mode source/multimode fiber systems by preventing light from the multimode fiber's center from interfering with the detector. When this is achieved, the detector is insulated from the effects of any pulse splitting, supporting data rates of greater than one GBPS by increasing the modal bandwidth.

Abstract: A method and apparatus are provided for connection-oriented switching in a communications network wherein a pre-established path is established between a select pair of an ingress switch and an egress switch. The use of pre-established paths enables a reduction in the total number of connections required inside the switch cloud, reduces the CPU load on trunk switches, and shortens the time for connection setup. In the embodiment described, the DA/SA fields of a MAC frame data packet are replaced with a "virtual path", which identifies the pre-established path between the ingress and egress switches. A "virtual circuit" is provided in another field of the modified packet which specifies the out-port and out-header on the egress switch for demultiplexing the modified packet upon receipt at the egress switch. The virtual circuit is exchanged between the ingress and egress switches at connection setup. The virtual path is assumed to already be in place, and known to both switches, prior to connection setup.

Abstract: Method and apparatus for establishing restricted broadcast groups in a switched network. The method assigns different virtual LAN identifiers (VLAN-IDs) to different subsets of associated end systems or access ports. Tables are maintained for mapping the VLAN-IDs with associated end systems and access ports. When a broadcast packet is received at a first switch, it is encapsulated with a VLAN header, including the VLAN-IDs, and sent out a multicast channel to all other switches in the network (domain). The original packet is sent out the other access ports of the receiving switch for the designated VLAN-IDs. The switches receiving the VLAN packet remove the header and send the original packet out access ports associated with the VLAN-IDs extracted from the header. The method provides a mechanism for forwarding broadcast packets of a protocol not supported by the switching mechanism, as well as multicast packets and unicast packets from undiscovered end systems.