Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus access regulation
Reexamination Certificate
1997-12-19
2001-05-08
Beausoleil, Robert (Department: 2181)
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus access regulation
C710S120000, C710S120000, C710S241000, C710S113000, C710S038000, C710S039000, C710S107000
Reexamination Certificate
active
06230229
ABSTRACT:
TECHNICAL FIELD
This invention relates to methods and systems for arbitrating path contention in an interconnect fabric utilizing serial or parallel crossbar switch technology.
BACKGROUND ART
Multiple cards having to communicate with each other have become widely used in computing systems. However, problems arise when the cards need to transfer data between each other and contend for communication path allocation.
In an interconnect fabric using serial or parallel crossbar switch technology, path arbitration is required when path contention occurs. For example, in a system having an NxN fully connected non-blocking crossbar, all of the cards in the system have their input paths fully connected to the crossbar. A problem arises when more than one source path needs to send data to the same destination path at the same time. A source path that is connected to a destination path may remain connected for a long period of time blocking all traffic intended for that path regardless of priority. The source path(s) end up continuously trying to gain access to the destination path until it becomes available without any assurance it will ever get connected to the desired destination path. This is referred to as a lock-out condition when one source path cannot make its connection. A fair system of arbitration would capture the connection requests and honor them in the order in which they were received.
Thus, there exists a need for path arbitration in such a system when path contention occurs, and to process high priority requests ahead of low priority requests.
DISCLOSURE OF THE INVENTION
It is a general object of the present invention to provide a method and system for allocating paths in a crossbar interconnect network.
In carrying out the above object and other objects, features, and advantages of the present invention, a method is provided for transmitting data among a plurality of cards in a crossbar interconnect network, each of the plurality of cards having source paths for originating the data and destination paths for receiving the data. The method includes the step of generating a connection request command from one of the source paths requesting access to a desired one of the destination paths. The method also includes the step of capturing the connection request command at the desired destination path. Still further, the method includes the step of processing the connection request command based on whether or not the desired destination path is busy so as to prevent a lock-out condition and to fairly allocate the desired destination path.
In further carrying out the above object and other objects, features, and advantages of the present invention, a system is also provided for carrying out the steps of the above described method. The system includes a source arbitrator associated with each of the cards and in communication with each of the source paths of the associated card for generating a connection request command from one of the source paths requesting access to a desired one of the destination paths. The system also includes a destination arbitrator associated with each of the cards for capturing the connection request command at the desired destination path and processing the request command based on whether or not the desired destination path is busy.
The above object and other objects, features and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.
REFERENCES:
patent: 4897833 (1990-01-01), Kent et al.
patent: 4985830 (1991-01-01), Atac et al.
patent: 5307466 (1994-04-01), Chang
patent: 5463486 (1995-10-01), Stevens
patent: 5533201 (1996-07-01), Benton et al.
patent: 5577204 (1996-11-01), Brewer et al.
patent: 5623698 (1997-04-01), Stephenson et al.
patent: 5657449 (1997-08-01), Osaki
patent: 5682485 (1997-10-01), Farmer et al.
patent: 5689644 (1997-11-01), Chou et al.
patent: 5699533 (1997-12-01), Sakai
patent: 5745709 (1998-04-01), Okabayashi et al.
patent: 5751710 (1998-05-01), Crowther et al.
patent: 5796966 (1998-08-01), Simcoe et al.
patent: 5832239 (1998-11-01), Gavin et al.
patent: 5835739 (1998-11-01), Bell et al.
patent: 5838937 (1998-11-01), Lee et al.
patent: 5854906 (1998-12-01), Van Loo
patent: 5857114 (1999-01-01), Kim
patent: 5859975 (1999-01-01), Brewer et al.
patent: 5949982 (1999-09-01), Frankeny et al.
patent: 6038630 (2000-03-01), Foster et al.
Hamre John D.
Hodapp, Jr. Don J.
Nelson Reed S.
Van Krevelen Christopher J.
Beausoleil Robert
Brooks & Kushman P.C.
Phan Raymond N
Storage Technology Corporation
LandOfFree
Method and system for arbitrating path contention in a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and system for arbitrating path contention in a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and system for arbitrating path contention in a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2570522