Method and apparatus of load sharing and improving fault tolerance in an interactive video distribution system

• US 20050028216A1
• Filed: 08/31/2004
• Published: 02/03/2005
• Est. Priority Date: 12/10/1999
• Status: Active Grant

• Current Assignee: Cox Communications Incorporated (Cox Enterprises Incorporated)
• Original Assignee: Cox Communications Incorporated (Cox Enterprises Incorporated)
• Inventors: Armstrong, James B., Nguyen, Hiep T., Vogel, Stephen R.
• Granted Patent: US 7,778,158 B2
• Time in Patent Office: Days
• US Class Current: 725/107
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06
• CPC Class Codes: H04N 21/23103 using load balancing strategies, e.g. by placing or distributing content on different disks, different memories or different servers storage management G06F3/0604; allocation of resources considering the load in multiprogramming arrangements G06F9/505; techniques for rebalancing the load in a distributed system G06F9/5083; access to distributed or replicated servers, e.g. load balancing, in data networks H04L67/1001
• CPC Class Codes: H04N 7/173 with two-way working, e.g. subscriber sending a programme selection signal

Abstract

Apparatus and method providing improved fault tolerance through redundancy of hardware and software suitable for use in a head-end of an interactive information distribution system. Communications between each of a head-end controllers and each of the server modules are coincidentally sent along at least two signal paths to provide to additional fault tolerance in the event one of the signal paths becomes inoperable. In one embodiment, a video switch comprises a plurality of I/O ports coupled between a plurality of server modules and a plurality of subscriber equipment for transferring video information between the server and the subscriber equipment. A primary and secondary switch controller are each coupled to the head-end controllers and the plurality of I/O ports. The primary switch controller is used for routing data packets containing said video information between the plurality of I/O ports. The secondary switch controller monitors status of the primary switch controller and I/O ports, and initiates a switchover event in an instance where the primary switch controller exhibits a failure.

Claims

1. In a video distribution system having provider equipment including a head-end, and associated subscriber equipment, a method of improving fault tolerance at a video switch, said method comprising the steps of:

asserting a switch controller READY signal at each of a plurality of switch controllers of said video switch at said head-end;

performing self-diagnostic tests and asserting a switch controller OK signal upon passing said self-diagnostic tests at each of said switch controllers;

indicating primary switch controller functionality by asserting a respective ONLINE signal by one of said plurality of switch controllers;

indicating secondary switch controller functionality by de-asserting a respective switch controller ONLINE signal;

monitoring said switch status via a secondary switch controller; and

initiating a switchover event in an instance where said primary switch controller is determined to be inoperable.

2. The method of claim 1, comprising the steps of:

periodically performing said self-diagnostic tests at said primary and secondary switch controllers;

initiating said switch controller OK signal after each periodic self-diagnostic test prior to a timer elapsing; and

de-asserting said switch controller OK signal in an instance where said primary or secondary switch controller fails to pass said self-diagnostic tests prior to said timer elapsing.

3. The method of claim 2, comprising the step of:

asserting said ONLINE signal by one of said plurality of switch controllers in a default mode of operation, wherein said asserting switch controller serves as an acting primary switch controller.

4. In a video distribution system having provider equipment and associated subscriber equipment, a method of improving fault tolerance at a video switch comprising a plurality of I/O ports and a plurality of switch controllers for providing content from said provider equipment to said subscriber equipment, said method comprising the steps of:

a) sending a periodic pinging command from an origination I/O port to a destination I/O port of said plurality of I/O ports via a primary switch controller of said video switch for testing a switch matrix of said primary switch controller;

b) setting a timer of said origination I/O port upon sending said periodic pinging command;

c) sending an acknowledgement signal from said destination I/O port to said origination I/O port via said switch matrix of said primary switch controller;

d) monitoring status of a status register in said origination I/O port via a secondary switch controller;

e) resetting said timer via said control register in an instance where said timer of said origination I/O port elapses before said switch matrix of said primary switch controller sends said acknowledgement to said origination I/O port; and

f) repeating steps (a-e) for each of said I/O ports of said plurality of I/O ports, where each I/O port alternately serves as an origination I/O port and a destination I/O port.

5. The method of claim 4 further comprising the step of:

initiating a switchover event in an instance where at least two of said plurality of I/O ports fail to receive said acknowledgment signals prior to their respective timers lapsing, wherein said secondary switch controller switches over to serve as said primary switch controller.

6. In a video distribution system having provider equipment and associated subscriber equipment, a method of improving fault tolerance at a video switch comprising a plurality of I/O ports and a plurality of switch controllers for providing content from said provider equipment to said subscriber equipment, said method comprising the steps of:

sending a periodic polling command to a control register in each of said plurality of I/O ports via a primary switch controller of said plurality of switch controllers;

setting a timer in each said I/O port via said control register upon receiving a respective periodic polling command;

monitoring status of a status register in each said I/O port via a secondary switch controller; and

setting an error message in a status register of an I/O port of said plurality of I/O ports, in an instance where a respective timer of said I/O port elapses before an associated control register resets said timer from a next polling command.

7. The method of claim 6 comprising the step of:

initiating a switchover event in an instance where a plurality of status registers in a plurality of I/O ports have said error messages set in said status registers, wherein said secondary switch controller switches over to serve as said primary switch controller.

8. The method of claim 6 comprising the step of broadcasting said polling command to a plurality of said I/O ports simultaneously.

9. The method of claim 6 comprising the step of pointcasting said polling command to a plurality of said I/O ports consecutively.