Edward B Carroll

US Patent:

56028270, Feb 11, 1997

Filed:

Jul 28, 1995

Appl. No.:

8/508794

Inventors:

Carl Lindeborg - Shrewsbury MA
Edward Carroll - Wrentham MA
James Moran - Methuen MA
David Bartolini - Charlton MA
John Griesing - Santa Clara CA
Liz Lindell - Sutton MA
Anthony D. Walker - Rougemont NC
Bradley S. Trubey - Cary NC

Assignee:

IBM - Armonk NY
3COM Corporation - Santa Clara CA

International Classification:

H04J 314

US Classification:

370223

Abstract:

Beacon recovery is performed separately on each module. After a module recognizes that a beacon condition has occurred, each module checks to determine if the defect or fault is on its module. If the defect is on the respective module, the module disconnects itself from the remaining modules in the network and transmits a beacon frame onto an upstream end of the group of stations on that module. Each port on the module is then tested to determine if the error lies in the corresponding station. This testing is based on the presence or absence of the beacon frame.

US Patent:

56469390, Jul 8, 1997

Filed:

Aug 8, 1995

Appl. No.:

8/512719

Inventors:

Carl Lindeborg - Shrewsbury MA
Edward Carroll - Wrentham MA
James Moran - Methuen MA
David Bartolini - Charlton MA
John Griesing - Santa Clara CA
Liz Lindell - Sutton MA
Anthony Dean Walker - Rougemont NC
Bradley S. Trubey - Cary NC

Assignee:

International Business Machines Coporation - Armonk NY
3Com Corporation - Santa Clara CA

International Classification:

H04L 1226
H04L 12433

US Classification:

370258

Abstract:

A token ring network performs address to port mapping by taking advantage of the abilities of the port switched modules and the neighbor notification process, in order to perform address to port mapping on each individual module. Ring monitors are switched from an upstream side of a port to a downstream side of a port when the neighbor notification process enters the port domain. The processor on the module records all the addresses received on the downstream side of the port, when the neighbor notification process is in the domain of that port. If it appears that the neighbor notification process is in the domain of two adjacent ports, the present invention only records addresses from the most downstream of the two adjacent ports, since such a situation is an indication that the upstream ports do not conform to MAC protocol. If a non-protocol station is connected to the last port in a module, the module will collect addresses from that port until the neighbor notification process enters the most upstream port of the module. At that point, addresses are no longer recorded in the most downstream port, and each set of addresses for each port are checked to determine if the last entry in each port has the ARI bits set to one and the source address is similar to the address of the most upstream neighbor of the module.