Cisco Systems Inc.

Cisco Technology, Inc.

Ramin Naderi

Ravi Periasamy

Gnanaprakasam Pandian

Kushal A Patel

Wayne Clark

Frank Bordonaro

Frank Gerard Bordonaro

David Lowry

Backup peers in an asymmetrically organized computer network are organized into a 'pool' of available devices that are activated as necessary. The network comprises a set of remote peers and a set of local peers directly associated with a central computational facility, the local peers facilitating connection between the remote peers and the central facility. During the capabilities exchange, the 'primary' local peer to which the remote peer connects provides a list of backup peer devices to the remote peer. If the primary peer fails (or if the rate of message exchange falls below some predetermined threshold), the remote peer can use the backup information to access a backup peer from the pool. The invention allows each backup peer to be assigned to multiple remote peers, with the total number of backup peers determined by aggregate backup utilization (rather than simply assigning an individual backup peer to each primary peer regardless of whether such a high level of redundancy is justified).

Backup peer pool for a routed computer network

The topology of a computer network is represented, for each routing device in the network, as a tree structure with the root of the tree designating the particular routing device. Tree nodes represent LANs, while arcs connecting the nodes represent other routing devices. Thus, the number of first-level links to children off the root is equal to the number of LANs connected to the source routing device, and those first-level links point to nodes representing the LANs (or LAN segments) directly connected to the source routing device. As a result of this representation, each routing device can store a representation of the entire network adequate to facilitate routing, but with much less memory utilization than a list of addresses. Furthermore, because the network is represented at a more general level than that of individual station addresses, changes to the topology of the network can be readily introduced without the need for extensive (e.g., address by address) reconfiguration.

Efficient path determination in a routed network

A hierarchical wide-area network architecture which conforms to the DLSw protocol is provided, in which multiple routers having a logical connection to one another are designated as a peer group. At least one router in each peer group is designated as a border peer, and functions as a gateway between the members of its group and other peer groups. The peer group structure reduces broadcast traffic on slow links by changing the source of the broadcast from a small access router with a relatively slow link to another, more powerful router, with a faster link on the network. More than one border peer can be included in each group, to share the transmission workload and act as a backup. The border peers can share information about the groups that they service and can cooperate to provide a single-point broadcast service to all of the users of the service. When two or more routers are connected to a network in parallel to provide back-up facilities, conditional filters are employed to prevent redundant operations. Different types of frames are handled by the two different routers, so that they share the communication load between them and make the most effective use of the available bandwidth.

Network having at least two routers, each having conditional filter so

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Saratoga, CA, United States of America

Ramin Naderi