Cabletron Systems, Inc.

Enterasys Networks, Inc.

William T Haggerty

Kurt A Dobbins

Stephen H Negus

Brendan J Fee

David L Cullerot

Kevin Yohe

Richard Bussiere

David Belser

Rich Soczewinski

Jeff Cioli

Paul Simoneau

Len Cormier

Kris Dobbins

Phillip Andlauer

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 &ldquo;virtual path&rdquo;, which identifies the pre-established path between the ingress and egress switches. A &ldquo;virtual circuit&rdquo; 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.

Aggregation of data flows over a pre-established path to reduce connections

Method and apparatus for establishing connections in a switch-based communications network for multicast traffic. A source receives a multicast packet on an access port from a source host, determines a group address in the multicast packet, and composes and sends a &ldquo;sender present&rdquo; message to other switches on its network ports. The receiving switches determine whether a local host wishes to join the group and if so, send a map message back toward the source switch on a predetermined path between the receiving switch and the source switch. A map message may terminate at a switch on the path that already has a connection for this group/source pair, and join into this connection as an additional output port. In this manner, a &ldquo;signal out, connect back&rdquo; method is provided for establishing a connection path from the sender to multiple receivers. In addition, multicast traffic can be sent across a switch/router interface in either direction, providing for controlled multicast traffic between router-based networks and switch-based networks.

Multicast switching

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.

Internet protocol (IP) work group routing

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.

Aggregation of mac data flows through pre-established path between

An interconnecting apparatus includes one or more interfaces. Each interface connects to a network. The interconnecting apparatus interconnects the networks attached to the interfaces. The device utilizes distributed autonomous forwarding engines on each interface in that each interface has a forwarding engine corresponding to it. Each forwarding engine only knows the configuration information and how to receive and transmit packets on the one interface to which it corresponds. Each forwarding engine acts independently to process packets, yet each interacts together to collectively provide packet forwarding which is protocol independent, interface independent, and scalable.

Network interconnecting apparatus having a separate forwarding engine

An object-oriented architecture for network layer routing is provided which distributes function and system behavior into autonomous router objects. By distributing these functionalities into each object, the services and data normally external to the object are imbedded or accessible within the object itself. In another sense, some objects are distributed across the network; e.g., a separate forwarding engine is provided at each network interface. In a preferred embodiment, each object has: (1) common, protocol-independent functions that are shared by all objects of that class; (2) their own configuration information; (3) accessibility through a router resource object for instantiation and control; (4) automatic persistence in NVRAM; (5) remote management capabilities; and (6) text names for navigation of a resource tree as a file system. These capabilities are in every object regardless of the specific protocol or application. This ensures a common architecture among many different systems/router components, a common method of control internally, a consistent order of instantiation and a common functional behavior.

Growing community of inventors

Dunstable, MA, United States of America

William T Haggerty