Session Manager Caching for Rapid VOD Setup
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Solution Overview
Problem
Conventional video on demand (VOD) session setup techniques require numerous messages between servers, leading to significant delays, which are unacceptable for applications like network personal video recorders (NPVR).
Innovation Solution
Implementing a session manager that caches information related to session setup, allowing it to establish VOD sessions quickly without exchanging messages with other VOD elements, thereby reducing the number of messages and setup time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional VOD session setup techniques are used with multiple server messages, then session establishment can be completed with proper coordination, but session setup delay increases to unacceptable levels (1 second or more)
Solution Approach 1:
The system performs preliminary actions by pre-fetching and caching video content and session information before the actual playback request. The session manager stores session setup information in a database, and the video server pre-loads video data into buffer memory, so that when a user requests playback, the session can be established immediately using cached data without requiring real-time coordination messages between servers.
Solution Approach 2:
The invention creates copies of session information and video content locally at the video server and session manager. Instead of querying multiple servers during session setup, the session manager maintains local copies of session data in its database, and the video server maintains local copies of video content in buffer memory. These copies enable rapid session establishment without extensive inter-server messaging.
2Adaptability or versatility
If streaming VOD services are provided over WAN to service large geographic areas, then service coverage is expanded, but responsiveness to subscriber requests deteriorates to unacceptable levels
Solution Approach 1:
The system segments the VOD service architecture into distributed video servers located in different geographic regions, each with local session managers and databases. This segmentation allows the system to service large geographic areas through multiple distributed nodes while maintaining fast responsiveness locally at each node, avoiding the latency of centralized WAN coordination for session setup.
Solution Approach 2:
Each video server performs preliminary actions by pre-loading video content into local buffer memory and the session manager pre-establishes session information in its local database. This preliminary action at each distributed node enables rapid local responsiveness to subscriber requests while the system maintains broad geographic coverage through its distributed architecture.
3Productivity
If the session manager caches session setup information locally, then session establishment speed increases to less than 1 second, but the system requires additional local storage and caching infrastructure
Solution Approach 1:
The session manager database serves multiple functions: it stores session setup information for rapid retrieval, maintains user authentication data, and tracks session state. The video server buffer memory also serves dual purposes by storing both video content for playback and session-related metadata. This multi-functionality reduces the need for separate specialized caching infrastructure, achieving fast session setup without proportionally increasing system complexity.
Data Source
AI summary
A technique for managing session setup for video on demand sessions involves caching information related to session setup for a session manager and then utilizing the cached information to setup a video on demand session for a client in response to a session setup request that is received from the client. Because information related to session setup is cached for the session manager, the session manager can utilize the information to establish a session without having to exchange messages with other video on demand elements, in particular other servers in the video on demand network. Reducing or eliminating the number of messages exchanged between video on demand elements enables video on demand sessions to be quickly and efficiently setup.