Arbitration system using linked table

• US 5,875,309 A
• Filed: 04/18/1997
• Issued: 02/23/1999
• Est. Priority Date: 04/18/1997
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Ziegler, John, Dandekar, Shirish B., Robins, Cary B., Itkowsky, Frank A.
• Primary Examiner(s): Ray, Gopal C.
• Application Number:
  US08/843,957
• Time in Patent Office: 676 Days
• Field of Search: 395/293, 395/303, 395/728, 395/292, 395/296, 395/860, 370/462, 370/447
• US Class Current: 710/113
• CPC Class Codes: G06F 13/36 for access to common bus or bus system
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches

Abstract

A computer network system containing a concentrator with a backplane that has a plurality of lines. The backplane contains data lines and control lines for managing and organizing the transfer of data between modules in the concentrator. The system contains an intelligent bus arbiter system that allow the selection of transmitting modules to occur at the same time as actual data transfer is going on between other modules. The bus arbitration system is provided for determining a sequence of bus access. A memory is provided for building a table comprising entries. Each of the entries represents a module slot identification number. Each entry also has an entry link portion which links a given entry to another entry. The system also includes arbiter logic cycling through or sequencing through and reading the table from one entry to another entry based on the entry link portion. The arbiter logic forms an output of a current slot identification number, corresponding to the module which is to have access to the bus. With this system, the number of entries having a particular module slot identification number relative to the total number of entries in the table determines a proportion of access to the bus of the module having the particular module slot identification number thereby allowing updating to the table to change access to the bus more readily.

Claims

1. A bus arbitration system for determining a sequence of bus access between a number of modules connected to the bus, comprising:

memory means for storing data including a table comprising entries, each of said entries representing a module slot identification number and having an entry link portion linking one entry to another entry;

write means for writing data to said table; and

arbiter logic means for cycling through and reading said table from one entry to another entry based on said entry link portion and forming an output of a current slot identification number which is to have access to said bus, whereby the number of entries having a particular module slot identification number relative to the total number of entries determines a proportion of access to the bus of the module having said particular module slot identification number thereby allowing updating to said table to change access to said bus more readily.

2. The bus arbitration system according to claim 1, wherein said write means includes means for updating said table including adding additional entries to said table for changing a proportion of access to the bus.

3. The bus arbitration system according to claim 1, wherein said write means includes means for updating said table including deleting entries from said table for changing a proportion of access to the bus.

4. The bus arbitration system according to claim 1, wherein software maintains a link back portion linking one entry to a previous entry in the table.

5. The bus arbitration system according to claim 1, wherein said memory means comprises data in the form of a second table comprising second table entries, each of said second table entries representing a module slot identification number and having a second table entry link portion linking one second table entry to another second table entry, said write means and writing data to said second table, said arbiter logic means switching from said table to said second table for cycling through and reading said second table from one second table entry to another second table entry based on said second table entry link portion and forming an output of a current slot identification number which is to have access to said bus allowing a creation of said table anew while using said second table.

6. The bus arbitration system according to claim 1, wherein said write means creates said table based on software for:

determining a table size to determine the number of entries in the table including determining a number of slots requiring a higher proportion of said bus and a number of slots requiring a lower proportion of said bus;

determining the number of entries for a slot based on the table size; and

assigning slots to the entries, based on the number of entries determined.

7. A computer network backplane and arbitration system, comprising:

a DATA line;

a plurality of modules connected to said DATA line, each of said plurality of modules including transmitter means for transmitting and receiving a packet onto and from said DATA line;

an arbiter selecting modules for access to said data line including;

a memory storing data including a table comprising entries, each of said entries representing a module slot identification number and having an entry link portion linking one entry to another entry;

a write device writing data to said table; and

arbiter logic cycling through and reading said table from one entry to another entry based on said entry link portion and forming an output of a current slot identification number which is to have access to said bus, whereby the number of entries having a particular module slot identification number relative to the total number of entries determines a proportion of access to the bus of the module having said particular module slot identification number.

8. The computer network backplane and arbitration system according to claim 7, wherein said write device includes means for updating said table including adding additional entries to said table for changing a proportion of access to the bus.

9. The computer network backplane and arbitration system according to claim 7, wherein said write device includes means for updating said table including deleting entries from said table for changing a proportion of access to the bus.

10. The computer network backplane and arbitration system according to claim 7, wherein software maintains a link back portion linking one entry to a previous entry in the table.

11. The computer network backplane and arbitration system according to claim 7, wherein said memory device comprises data in the form of a second table comprising second table entries, each of said second table entries representing a module slot identification number and having a second table entry link portion linking one second table entry to another second table entry, said write device writing data to said second table, said arbiter logic switching from said table to said second table for cycling through and reading said second table from one second table entry to another second table entry based on said second table entry link portion with and forming an output of a current slot identification number which is to have access to said bus allowing a creation of said table anew while using said second table.

12. The computer network backplane and arbitration system according to claim 7, wherein said writing device creates said table based on software for:

determining a table size to determine the number of entries in the table including determining a number of slots requiring a higher proportion of said bus and a number of slots requiring a lower proportion of said bus;

determining the number of entries for a slot based on the table size; and

assigning slots to the entries, based on the number of entries determined.

13. A process for determining a sequence of bus access between a number of modules connected to the bus, comprising the steps of:

storing data in a memory, the data including a table comprising entries, each of said entries representing a module slot identification number and having an entry link portion linking one entry to another entry;

writing data to said table;

cycling through and reading said table from one entry to another entry based on said entry link portion; and

forming an output of a current slot identification number which is to have access to said bus, whereby the number of entries having a particular module slot identification number relative to the total number of entries determines a proportion of access to the bus of the module having said particular module slot identification number.

14. The process according to claim 13, further comprising:

updating said table including adding additional entries to said table for changing a proportion of access to the bus.

15. The process according to claim 13, further comprising:

updating said table including deleting entries from said table for changing a proportion of access to the bus.

16. The process according to claim 13, further comprising:

providing each entry with a link back portion linking one entry to a previous entry in the table.

17. The process according to claim 13, further comprising:

providing a second table comprising second table entries, each of said second table entries representing a module slot identification number and having a second table entry link portion linking one second table entry to another second table entry;

reading data from said second table and writing data to said second table;

switching from said table to said second table for cycling through said second table from one second table entry to another second table entry based on said second table entry link portion;

forming an output of a current slot identification number which is to have access to said bus; and

creating said table anew while using said second table.

18. The process according to claim 13, further comprising:

creating said table including;

determining a table size to determine the number of entries in the table including determining a number of slots requiring a higher proportion of said bus and a number of slots requiring a lower proportion of said bus;

determining the number of entries for a slot based on the table size; and

assigning slots to the entries, based on the number of entries determined.