Method and apparatus for dynamically controlling data routes through a network

• US 5,796,966 A
• Filed: 05/05/1997
• Issued: 08/18/1998
• Est. Priority Date: 03/01/1993
• Status: Expired due to Term

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Varghese, George, Simcoe, Robert, Thomas, Robert E.
• Primary Examiner(s): Harvey, Jack B.
• Assistant Examiner(s): Myers, Paul R.
• Application Number:
  US08/850,975
• Time in Patent Office: 470 Days
• Field of Search: 395/311, 395/312, 395/200.68, 395/200.62, 395/736, 370/60, 370/94.1, 370/360
• US Class Current: 710/316
• CPC Class Codes: H04L 12/1881 with schedule organisation, e.g. priority, sequence management
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports

Abstract

A mechanism for operating a configurable switch to dynamically (i) route each of the data packets in an ordered string from a particular switch input port through a selected member output port of a hunt group; and (ii) route data packets which need not be transmitted in order from the input ports to available member output ports of the hunt group, as the members become available. A controller assigns each input port a service number, and directs member output ports to handle requests for ordered data packet transmissions from input ports with particular service numbers, such that the ordered transfers from an input port are handled by a single member of each group. The input port broadcasts, through the switch, a request to send ordered data packets through a particular hunt group and includes its service number in the request. The group member assigned to handle ordered transfers from the input port responds by identifying itself. Thereafter, the input port sends its ordered data packets to the identified member. Unordered data packets are queued and routed dynamically through the members of the group, as the members become available. In a local area network, data is sent from a source station to file servers using server group identifiers for multiple-route transfers or individual server identifiers for single-route transfers.

Claims

1. A method of operating a configurable switch to send data between source stations connected to switch input ports and destination stations that receive data packets from switch output ports, said configurable switch to dynamically select between routing modes, where said switch output ports are configured as hunt groups, the method including the steps of:

A. assigning a service number to each switch input port;

B. assigning one or more service numbers to each switch output port which is a member of a hunt group and which handles the transfer of single-route data including a string of data packets which must arrive at a particular destination station in a particular order;

C. dynamically determining whether a data transfer is a single-route data transfer or a multiple-route data transfer;

D. if data is to be transferred as single-route data

i. broadcasting to the members of a hunt group associated with the particular destination station a data transfer request for a single-route data transfer which includes the service number assigned to the requesting input port;

ii. sending, from the member which is assigned the service number included in the data transfer request, a member identifier and a single-route queue position number to the requesting input port;

iii. broadcasting to the input ports a message from the assigned member that the member is available to perform a single-route data transfer;

iv. responding to the message by sending to the assigned member data from the input port which is in the first position in the single-route queue;

or

E. if data is to be transferred as a multiple-route data transfer including one or more data packets which may arrive at a particular destination station in any order

i. broadcasting to the members of a hunt group associated with the particular destination station a data transfer request from an input port;

ii. returning from a designated member to the requesting input port a multiple-route queue position number;

iii. broadcasting from a next available member of the hunt group to the input ports, a message that the member is available to perform a multiple-route data transfer;

iv. responding to the message by sending, to the member station identified in the message, data from the input port which is in the first position in the multiple route queue.

2. The method of claim 1 further including the steps of:

a. for each message from a member indicating availability to handle a single-route data transfer, decrementing the single-route queue position numbers held by each of the input ports which are serviced by the member; and

b. for each message from a member identified as available to handle a multiple-route data transfer, decrementing the multiple-route queue position numbers held by each of the input ports which are queued to send data to the hunt group.

3. The method of claim 1, further including the steps of:

a. storing in each of the members, in a table addressed using the service numbers, the service numbers assigned to the member; and

b. each member, after receiving a single-route data transfer request, using the service number included therein to enter the table to determine if the member should respond to the request.

4. The method of claim 1 further including the steps of:

a. if the request is for a single-route data transfer, incrementing the single-route queue position number indicating the length of the queue of the member assigned to service this request, and

b. decrementing the single-route queue position number when the member handles a single-route data transfer, and

c. if the request is for a multiple-route data transfer, incrementing the number indicating the length of the group queue, and

d. decrementing the group multiple-route position number when any member of the group handles a multiple-route data transfer.

5. A method of operating a configurable switch to send data between source stations which transfer data packets to switch input ports and destination stations that receive data from switch output ports, said configurable switch to dynamically select between routing modes, said output ports configured as hunt groups, the method including the steps of:

A. assigning a service number to each switch input port;

B. assigning one or more service numbers to each member of a hunt group;

C. dynamically determining whether a data transfer is a single-route transfer or a multiple-route transfer;

D. if data is to be transferred as single-route data including a string of data packets which must arrive at a particular destination station in a particular order

i. broadcasting a request from an input port to a hunt group associated with the particular destination station requesting the identity of the member which is assigned to a particular service number; and

ii. sending data from the input port to the identified member;

E. if the data is to be transferred as multiple-route data including one or more data packets which may arrive at a particular destination station in any order

i sending data to a hunt group associated with the particular destination station;

ii. sending the data to the member which is then available.

6. A system for sending data over a network, the system including:

A. a configurable switch;

B. a plurality of source stations for transmitting data through the switch, the source stations transferring the data to switch input ports;

C. a plurality of destination stations for receiving data transmitted through the switch, the destination station receiving data from switch output ports;

D. a controller for

i assigning a service number to each switch input port;

ii. assigning one or more service numbers to each switch output port which is a member of a hunt group and which handles single-route data transfers including transfer of a string of data packets which must arrive at a particular destination station in a particular order, such that each service number is assigned to one such member of each group;

E. the switch determining whether a data transfer is a single-route transfer or a multiple-route transfer and broadcasting data transfer messages from the input ports to the member output ports of a group, and

i if the requested data transfer is a single-route transfer, sending to the requesting input port from the member output port assigned the same service number as the requesting input port, a single-route queue position number and a member output port identifier and thereafter when the request is in the first position in the queue sending data from the requesting input port to the assigned member output port;

ii. if the requested data transfer is a multiple-route transfer including transfer of one or more data packets which may arrive at a particular destination station in any order, sending from a designated member output port to the requesting input port a multiple-route queue number and when the requesting input port is in the first position in the queue sending data from the requesting input port to the member output port then available to handle the transfer,

the switch dynamically selecting between single-route routing and multiple-route routing and dynamically configuring the switch input ports and output ports according to the selected data transfer mode.

7. A system for sending data over a network, the system including:

A. a plurality of source stations for transmitting data;

B. a plurality of destination stations for receiving data from the source stations;

C. a controller for

assigning a service number to each source station;

ii. assigning one or more service numbers to each destination station which is a member of a hunt group, such that each service number is assigned to one member of each hunt group;

iii. dynamically determining whether a data transfer is a single-route transfer or a multiple-route transfer and dynamically configuring switch input ports and output ports according to a selected data transfer mode;

D. a source station broadcasting data to the destination stations which are members of a hunt group, if the data is multiple route data including one or more data packets which may arrive at a particular destination station in any order; and

E. the source station sending single route data including a string of data packets which must arrive at a particular destination station in a particular order to the particular destination station in the hunt group which is assigned to service source stations assigned the same service number as this source station.

8. The system for sending data of claim 7, wherein the source station sends a request to a hunt group of destination stations, the source station thereby seeking from the group the identity of the destination station responsive to the service number assigned to the source station.