Method and apparatus providing connection-oriented services for packet switched data communications networks. Directory services include distributed discovery of MAC addresses and protocol alias addresses. Topology services include a link state topology exchange among switches, which provides each switch with a complete topology graph of the network. This enables an access switch receiving a data packet to determine a complete path from a source end system to a destination end system. Another service includes resolution of broadcast frames to unicast frames, in order to reduce the amount of broadcast traffic. Policy restrictions may be applied prior to connection setup. Path determination services enable multiple paths from a source to a destination. Connection management includes source routed mapping of connections on the desired path. A distributed call rerouting service is provided wherein if a link on an active path fails, each switch receives a topology change notification and unmaps any connection involving the failed link. A broadcast/unknown service provides restricted flooding of nonresolvable packets. Furthermore, connection-oriented switching is provided based on the source and destination MAC addresses as a connection identifier. Still further, resolution of networks outside the switch domain is enabled by access switches listening for network and server route advertisements and maintaining best routes to said networks and servers. The best route metrics may be combined with best path metrics to determine a path from a first access switch to an egress switch connected to the external network.

Distributed connection-oriented services for switched communication networks

Two network communication protocols, one for routing and one for mobility management, are presented that are particularly suited for use with ad-hoc networks. The routing protocol is a proactive-reactive hybrid routing protocol that limits the scope of the proactive procedure to the node's local neighborhood. Routing zones are defined for each node that include nodes whose distance from the subject node in hops is at most some predefined number, referred to as the zone radius. Each node is required to know the topology of the network within its routing zone only. The reactive procedure is limited during route discovery to queries of only those nodes located on the periphery of routing zones. In this manner, the queries hop across nodes in distances of zone radius, thus limiting the scope of the reactive procedure. The zone radius is preferably adjustable to accommodate different and differing network topologies and network operational conditions in the most efficient manner. The mobility management protocol relies on some network nodes assuming the mobility management function. In this scheme, each network node is “associated” with one or more mobility management nodes. The mobility management nodes form a virtual network which is embedded within the actual ad-hoc network. Each mobility management node knows the location of all nodes within its zone, and communicates this information to any other mobility management node that requests it.

Routing and mobility management protocols for ad-hoc networks

An integrated voice gateway system for use within a company which can route a voice telephone call between parties at two different locations over an IP network or over the PST NETWORK. The system can route a voice telephone call from a first location within the system to a second location within the system via the IP network, and then from the second location to a third location via the PST NETWORK. The integrated voice gateway system includes a gateway server which serves as an intranet/Internet telephony gateway. The gateway server routes intra-company voice or facsimile (fax) calls, over the company's intranet or the public Internet. The gateway server provides an alternate voice network to the PST NETWORK for a company. This alternate network is provided at a much lower cost. The gateway server is a combination of hardware and software components which reside on a PC server platform. The gateway server is coupled to a customer premise telephone system, i.e. a PBX via a T1 or E1 trunk for larger systems, or an analog trunk for smaller systems. The gateway server is coupled to the company's intranet via industry standard connections. The gateway servers in a multi-site company are coupled together via the company's intranet or wide area network (WAN) into a gateway network. The gateway server uses PBX call status links to provide many unique and useful features which are otherwise unavailable. The gateway server uses T1 inband ANI, PRI, QSIG or industry standard CTI applications programming interfaces (API) and works with any PBX which supports any of these call status links. The gateway server is equipped with a database of user and gateway objects and attributes, and provides many unique features including caller's name based on caller phone number, address translation, gateway network routing information, user authentication, etc. This database can be integrated with industry standard enterprise directory services systems including any directory which supports the Lightweight Directory Access Protocol (X.500) (LDAP) interface.

Apparatus and method for integrated voice gateway

A system in which a single VLAN architecture spans multiple VLAN transport protocols and technologies, including a method and system in which multiple different VLANs may be combined in a single enterprise network. Each LAN-switch in the sytem identifies each frame with an identifier, and associates that identifier with particular VLAN identifiers for each type of VLAN technology. When a frame is bridged or routed from a first type of VLAN to a second type of VLAN, the first VLAN encapsulation is removed and the second VLAN encapsulation is added, with appropriate change in the VLAN identifier for the frame or packet. The identifier may also be implicit for the frame, such as when a particular set of sender's MAC addresses are identified with a particular VLAN. Individual VLANs, of whatever architecture, may be added, configured or reconfigured, modified, or deleted, using control tools associated with the multiple VLAN architecture system. Individual ports may be associated with particular VLANs, or may be designated "dynamic" so that frames or packets associated with those ports are associated with particular VLANs in response to source or destination addresses or other information.

Multiple VLAN architecture system

The invention provides a method and system for switching in networks responsive to message flow patterns. A message “flow” is defined to comprise a set of packets to be transmitted between a particular source and a particular destination. When routers in a network identify a new message flow, they determine the proper processing for packets in that message flow and cache that information for that message flow. Thereafter, when routers in a network identify a packet which is part of that message flow, they process that packet according to the proper processing for packets in that message flow. The proper processing may include a determination of a destination port for routing those packets and a determination of whether access control permits routing those packets to their indicated destination.

Network flow switching and flow data export

A method and apparatus for selecting routes in a hierarchical communications network wherein a number of mutually isolated areas are provided at a first level, which areas are mutually linked at a second level. In the network, routing devices are provided at both levels. For selecting a route from a first area to a second area, use is made of routing information stored in the routing devices of the first level, relating to the first level and to reaching the nearest routing device of the second level. Use is also made, in the routing devices of the first level, of routing information relating to the second level.

Routing method for a hierarchical communications network, and a hierarchical communications network having improved routing

The invention relates to a method of selecting routes in a communications network comprising a number of mutually isolated areas (A1, A2, A3, A4) at a first level, which areas are mutually linked at a second level, and in which network routing devices (R1-1, R1-2, ..., R2-5) are provided at both levels. For selecting a route from a first area (e.g. A1) to a second area (e.g. A4), in said method use is made of routing information, stored in the routing devices (R1-1, R1-2, ...) of the first level, relating to the first level and to reaching the nearest routing device (e.g. R2-5) of the second level. According to the invention, use is also made, in the routing devices of the first level, of routing information relating to the second level. The invention also provides a hierarchical communications network in which said method is applied.

Adrianus A. L. Reijnierse

Papers

Routing method for a hierarchical communications network, and a hierarchical communications network having improved routing

Routing in a hierarchical communication network