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
• Maintenance of information about the entire CDS topology and all the delivery services. This
includes upkeep of a list of Service Engines in the same delivery service that is used for distributing
prefetched, dynamic, and live stream content.
• Maintenance of the database that stores and distributes metadata about the content, and the topology
and delivery service information.
• Distribution of content on a per-delivery service basis, where the flow path of content could differ
from one delivery service to another.
Content Acquirer
Every delivery service requires a Content Acquirer, which is a CDA that resides on every Service
Engine. The Content Acquirer CDA becomes active when the Service Engine is designated as the
Content Acquirer in a delivery service. The Content Acquirer has the following functions and
capabilities:
• Fetches content from origin servers using HTTP, HTTPS, FTP, or CIFS (Dynamic ingest supports
HTTP only).
• Supports the NT LAN Manager (NTLM) and basic authentication for ingesting content from the
origin servers.
• Creates and distributes the metadata for each of the prefetched contents according to the Manifest
file and the information returned by the origin server.
Once the Content Acquirer has ingested the content and distributed the metadata, it creates a database
record for the metadata and marks the content ready for distribution. All other types of ingest (dynamic,
hybrid, and live stream) are handled by the Content Acquirer as well.
Internet Streamer
All Internet Streamers participating in a delivery service pull the metadata from a peer Internet Streamer
called a forwarder, which is selected by the internal routing module. Each Internet Streamer
participating in a delivery service has a forwarder Internet Streamer. The Content Acquirer is the
top-most forwarder in the distribution hierarchy. In the case of prefetched ingest, each Internet Streamer
in the delivery service looks up the metadata record and fetches the content from its forwarder. For live
or cached content metadata, only the metadata is distributed.
The content associated with the metadata for live and cached content is fetched by the specified protocol
engine, which uses the dynamic ingest mechanism. When a request for a non-prefetched content arrives
at an Internet Streamer, the protocol engine application gets the information about the set of upstream
Internet Streamers through which the content can be acquired. In the case of dynamic ingest, the Internet
Streamer uses the cache routing function to organize itself as a hierarchy of caching proxies and
performs a native protocol cache fill. Live stream splitting is used to organize the Internet Streamers into
a live streaming hierarchy to split a single incoming live stream to multiple clients. The live stream can
originate from external servers or from ingested content. Windows Media Engine, Movie Streamer
Engine, and Flash Media Streaming Engine support live stream splitting.
The Internet Streamers use service control to filter and control incoming requests for content. The
service rules and the PacketCable Multimedia (PCMM) Quality of Service (QoS) control are some of the
functions that are encapsulated under the Service Control option in the Internet Streaming CDSM.
The Internet Streamers send keep-alive and load information to the Service Router that is participating
in the same delivery service. This information is used by the Service Router to choose the most
appropriate Internet Streamer to handle the request.