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

• US 7,778,158 B2
• Filed: 08/31/2004
• Issued: 08/17/2010
• 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.
• Primary Examiner(s): Rao; Seema S
• Assistant Examiner(s): WONG, XAVIER S
• Application Number:
  US10/930,154
• Publication Number:
  US 20050028216A1
• Time in Patent Office: 2,177 Days
• Field of Search: None
• US Class Current: 370/217
• 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:

initializing a plurality of switch controllers coupled to each of a plurality of headend controllers by a plurality of switches controlled by the plurality of switch controllers;

asserting a switch controller READY signal at each of a plurality of switch controllers coupled to said video switch at said head-end to indicate operational status of each of the plurality of switch controllers;

performing self-diagnostic tests on each of the plurality of switch controllers by testing communication between each of a plurality of I/O ports through each of the plurality of switch controllers;

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 the plurality of I/O ports and the primary switch controller by the secondary switch controller; and

initiating a switchover event when said secondary switch controller determines during the monitoring of the plurality of I/O ports and the primary switch controller that the primary switch controller is 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 when 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 to cause said plurality of switch controllers to serve 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) initializing a plurality of switch controllers coupled to each of a plurality of headend controllers by a plurality of switches controlled by the plurality of switch controllers, the plurality of switch controllers including a primary switch controller and a secondary switch controller;

b) 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 the primary switch controller of said video switch for testing a switch matrix of said primary switch controller;

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

d) 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;

e) monitoring by the secondary switch controller a status of the primary switch controller and a status register in said origination I/O port;

f) resetting said timer by the secondary switch controller in an instance that 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;

g) repeating steps (b-f) for each of said I/O ports of said plurality of I/O ports so that each I/O port alternately serves as an origination I/O port and a destination I/O port; and

h) initiating a switchover event when said secondary switch controller determines during the monitoring of the status of the primary switch controller and the status register of each of said I/O ports of said plurality of I/O ports that the primary switch controller is inoperable.

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

initiating the switchover event when at least two of said plurality of I/O ports fail to receive said acknowledgment signals prior to their respective timers lapsing to cause said secondary switch controller 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:

initializing a plurality of switch controllers coupled to each of a plurality of headend controllers by a plurality of switches controlled by the plurality of switch controllers, the plurality of switch controllers including a primary switch controller and a secondary switch controller

sending a periodic polling command to a control register in each of said plurality of I/O ports via the 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 by the secondary switch controller a status of the primary switch controller and a status register in each said I/O port;

setting an error message in the status register of an I/O port of said plurality of I/O ports when a respective timer of said I/O port elapses before an associated control register resets said timer from a next polling command; and

initiating a switchover event when said secondary switch controller determines during the monitoring of the status of the primary switch controller and the status register of each of said I/O ports of said plurality of I/O ports that the error message indicates that the primary switch controller is inoperable.

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

initiating the switchover event when a plurality of status registers in a plurality of I/O ports have said error messages set in said status registers to cause said secondary switch controller 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.