3Com Corporation

Yoram Shamir

Sharon Barkai

Sarit Shani

Haim Rochberger

Eldad Bar-Eli

Miki Kenneth

A method of providing redundancy and load sharing among multiple LECSs in an ATM network. The method creates and maintains a plurality of lists on each of the switches. Each list is an ordered set of LECSs that combine to create an active LECS list. The network is divided into a plurality of groups wherein each group is assigned one of the active LECS lists. The order of each active LECS list is unique in that no two groups have the same order of LECS. The first LECS on each list has the highest priority and is always the first choice when a request to join a VLAN is received from one of the connected LECs. If the primary lECS fails or cannot be reached for any reason, the switches utilize the second LECS on the list. Splitting up the network into multiple groups and assigning different lists serves to provide load sharing among the LECS. In the event the currently active LECS fails, the next on the list takes overt thus providing redundancy.

Method of providing redundancy and load sharing among multiple LECs in an asynchronous mode network

A method for creating and resolving split VLANs in ATM networks. The method utilizes a Network Management System (NMS) and a standard management protocol such as SNMP. The method monitors the network by continuously polling all the devices in the network. Status related information collected by the NMS is used to construct a physical and logical topology of the network. In response to the detection of one or more physical splits in the network, the NMS creates one or more corresponding logical splits in the network by splitting one or more VLANs. In the case of two split portions, the split VLAN can be created if a redundant LES and second LECS are located on the side of the split which does not include the primary LES. The second LECS is configured to use the address of the redundant LES in replying to requests to join an ELAN from the disconnected LECs. The repair of the physical split is detected by the NMS and, in response, the NMS modifies the databases of all the LECS in the ELAN so that the same primary LES address is returned to any LEC requesting to join an ELAN. LECs previously attached to the redundant LES are disconnected and subsequently attached to the primary LES.

Method of resolving split virtual LANs utilizing a network management system

A method whereby local area network (LAN) multicast traffic flows are defined and set up by the network management system (NMS). Network efficiency is maximized and performance degradation of the network and workstations connected thereto is reduced. The method utilizes standard 802.1D bridging infrastructure built into conventional level 2 network switching devices to permit a administrator to define a multicast flow, otherwise known as a virtual LAN (VLAN) or a 'Session VLAN,' as a multicast application that can be mapped to a multicast MAC address. The multicast MAC address is then utilized in the transmission of the multicast messages. The NMS declares a session VLAN across all the level 2 devices in the network utilizing standard SNMP and members of the session VLAN can be added and removed. Each device then translates the SNMP requests to an operation on its standard 802.1D static addresses.

Growing community of inventors

Kiriat Ono, Israel

Yoram Shamir