[TS-4701] Add a new latched parent selection strategy.

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Implemented
• Fix Version/s: 7.1.0, sometime
• Component/s: Parent Proxy
• Assignee: John Rushford
• Reporter: John Rushford
• Created: 25/Jul/16 16:56
• Updated: 14/Oct/16 14:27
• Resolved: 14/Oct/16 14:27

Description

For live linear video we are utilizing parent selection to round robin to origin servers in the event of a origin server failure, parent_is_proxy=false and round_robin=false. With this round robin strategy, the first parent in the parent.config list is always selected. In the event of a connection failure, a new parent is selected from the list. This works fine except that switching to a new parent is expensive, in that the client has to retune because the abr manifests between origins are different. A single retune can be tolerated but, after the parent retry time has elapsed, the round robin strategy will revert back to the original parent when it becomes available. This causes a second retune. In order to minimize client retuning, I'd like to add a new round robin strategy that is similar to round_robin=false but the new strategy would stay "latched" to the selected parent and remain "latched" until such time that a connection failure warrants using a new parent. I propose calling this strategy "latched" as in an electronic latch that becomes fixed in a particular state when triggered. This strategy would be a minor modification to ParentRoundRobin and ParentSelection.

Issue Links

• links to: GitHub Pull Request #1084