Cisco Technology, Inc.

Scott Allen Bales

Frank Gerard Bordonaro

Uwe Sellentin

Andrew Joseph Mead

Arun G Khanna

John Lautmann

Arunkumar Bhushappagala Thippeswamy

Patricia Ann Webster

A processor-based system configured for searching in dynamically balanced trees is configured for linking the most often-searched elements of the tree to optimize search performance. Data elements include pointers for a tree-based index ordering and a doubly-linked list based index ordering. A background process links the most often-searched elements according to the linked list ordering and maintains the linked list ordering by first determining those elements having the highest importance values, defined as a number of times an element is successfully searched relative to aging or decay function. The linked list ordering is then arranged based on descending importance values. Each element also includes a go-to-tree flag, indicating to a search engine the point at which it is no longer beneficial to continue searching according to the doubly-linked list ordering. Hence, a search engine that begins searching the elements according to the doubly-linked list ordering will begin searching of the tree structure for the specified key entry in response to detecting an element having a go-to-tree flag set to true. Hence, the doubly-linked list may optimize search performance when the most often-searched elements may be deep within a tree, while insuring that unnecessary overhead is not introduced into the search routine.

Arrangement for enhancing weighted element searches in dynamically balanced trees

A transparently-bridged wide area network connecting Ethernet/IEEE 802.3-based local area networks uses redundant proxy devices on each LAN for internetwork communications. The proxy devices, implemented as data link switching (DLSw) devices, prevent looping of traffic such as explorer frames by sharing their MAC addresses to enable the proxy devices to recognize data packets from another proxy device. Incoming explorer frames from the wide area network are modified by performing an address substitution, where the source address in a received explorer frame is replaced with the address of the local proxy device. The proxy device then outputs the modified explorer frame onto the local area network. Any other proxy device on that same local network will then be able to detect the modified explorer frame as a frame forwarded by another proxy device, as opposed to a data frame from an end station on that local area network. Hence, redundant DLSw-type proxy devices may be implemented on a local area network while maintaining a stable and a robust communications system.

Arrangement for preventing looping of explorer frames in a transparent bridging domain having multiple entry points

A transparently-bridged wide area network connecting Ethernet/IEEE 802.3-based local area networks uses redundant proxy devices on each LAN for internetwork communications. The proxy devices on a given LAN, implemented as data link switching (DLSw) devices, identify amongst each other a master proxy device for mediating services to be provided to an end station on the local area network. Each proxy device connected to the local area network sends a request to the identified master proxy device in response to detecting a frame transmitted by an end station on the local area network, for permission to establish a circuit connection for transfer of the frame via a wide area network. The master proxy device, based on prescribed criteria, selects one of the proxy devices for transferring the frame, and sends a grant response to the selected proxy device. The master proxy device sends an 'inuse' response as a denial response to the other proxy devices indicating the corresponding request has been denied, thereby avoiding contention for proxy services. Databases within the proxy devices track the request, grants, and denials to minimize generation of repeated requests. The inventory of granted requests may also be modified based on failures detected within the master proxy device, or any proxy device having received grants. Hence, redundant DLSw-type proxy devices may be implemented on a local area network while maintaining a stable and a robust communications system.

Arrangement for controlling network proxy device traffic on a

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Durham, NC, United States of America

Scott Allen Bales