International Business Machines Corporation

Keith E Karlsson

Robert E Moore

Cedell Adam Alexander, Jr

Arthur A Daniel

Kurt E Augustine

James L Ashton

Kathleen D Lee

Daniel E Levenson

Michael Willett

David N Jacobson

Chih-Wei Chao

Jacalyn L Frantz

To insure connection resiliency two LECs are defined in normal practice in which a lengthy and extensive recovery procedure is enforced in case of an ATM interface failure. In the present invention only one LEC is configured. This LEC is configured to be If the active ATM interface fails, the bridge is not notified of the failure as would normally happen. The LEC associates itself with the alternate ATM and rejoins the ELAN via the alternate ATM interface. The ELAN Join Procedure is one of the LAN Emulation protocols. After the ELAN has rejoined, the LEC automatically re-establishes the previously existing Data Direct VCCs (bi-directional point to point LAN Emulation connection established from one LEC to another) using its LE_ARP (LAN Emulation Address Resolution Protocol) cache entries.

Method and system for LEC resiliency with fast failover

A plurality of processes share a single set of non-resettable counters which are sampled periodically. Each process maintains a list of counter relationships unique to its own process and compares at each sample time the current sampled counter values with a selected function of previously received counter values for each relationship in its list and establishes a counter reset value which is a selected function of the current sampled value when the previously selected function is satisfied.

Control of non-resettable counters by multiple processes

Method and apparatus in a communications controller to transfer data between a host computer and the controller. The communications controller includes a channel adapter (CA) and a central control unit (CCU) for controlling the operation of the CA. In response to a request from the CCU, the channel adapter transfers data between the host computer and the channel adapter to or from a linked list of buffers until all messages contained in the linked list have been transferred. Only after all messages in the present transmission have been transferred, the CA interrupts the CCU to signal completion. In a preferred embodiment, the channel adapter includes a microprocessor and a read-only-memory containing programmed instructions for controlling the microprocessor. Together, the microprocessor under control of the read-only-memory instructions form an apparatus for carrying out the method.

Method and apparatus for buffer chaining in a communications controller

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Raleigh, NC, United States of America

Keith E Karlsson