Specifications
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Cisco Internet Streamer CDS 2.0-2.3 Software Configuration Guide
OL-13493-04
Chapter 1 Product Overview
Content Delivery System Architecture
The Movie Streamer Engine is an RTSP streaming engine that supports Third Generation Partnership
Project (3GPP) streaming files (.3gp). Support of 3GPP provides for the rich multimedia content over
broadband mobile networks to multimedia-enabled cellular phones.
Note The streaming capability of Movie Streamer Engine only depends on the movie file format or stream
transport type. It is independent of codec types. Movie Streamer supports any client player that can fetch
media streams by way of RTSP or RTP. However, the client player must have the correct codec in order
to render the stream correctly.
The Movie Streamer Engine can act as both a server and a proxy. It streams prefetched or RTSP-cached
content to RTSP clients, acts as a proxy for client requests, splits a live stream into multiple live streams,
and caches content requested from remote servers.
After the RTSP request comes into the Movie Streamer, the URI in the RTSP request is modified to
reflect the result of the mobile capability exchange. The Movie Streamer checks with the storage
function on the Service Engine to see whether the content is stored locally. If the content is not found or
if an RTSP-cached content version needs freshness validation, the Movie Streamer engages the Movie
Streamer proxy.
In the case of an RTSP-cached content version verification, the Movie Streamer proxy forwards the
DESCRIBE request to the origin server for a response containing the Last-Modified-Time header in the
response. If the Last-Modified-Time matches the cached version, the Movie Streamer streams the cached
content; otherwise, the Movie Streamer proxy forwards the request to the origin server for RTSP
negotiation. Then, a client session and a server session are created.
• The server session is responsible for connecting to the origin server to fetch the content and cache
it locally. The server session generates the media cache file and the linear hint files.
• The client session is responsible for streaming the locally cached file to the client.
• The client and server sessions are separated so that multiple server sessions can be spawned for the
same URL to cache content from different starting points or at faster speeds, or both. This increases
the speed of fetching the content. The client session starts to stream from the cached content that the
server session is writing.
The Movie Streamer proxy works like the cache fill operation in the Web Engine and the Windows Media
Engine. There are two options:
1. Hierarchical Caching Proxy—If content is not found locally, the Movie Streamer checks the
upstream Service Engines first before pulling the content from origin server.
2. Static Caching Proxy—The administrator statically configures Service Engines as upstream proxies.
The Movie Streamer supports basic pass-through proxy mode for certain conditions where caching
cannot be performed. Such conditions include, but are not limited to, the Service Engine running out of
disk space.
Transport Types
Prefetched content can be delivered by the non-accelerated method or the accelerated method.
Non-prefetched content (proxied or cached content) is always delivered by the accelerated method. The
content is delivered to the client device by means of one of the following mechanisms:
• Non-Accelerated—This method has limited concurrent streams and total throughput, but supports
many transport formats. The non-accelerated method supports the following transport formats:
–
RTP over UDP
–
Reliable UDP