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
geographical location of the Service Engines listed in the Coverage Zone file, and the closest and
least-loaded Service Engine is selected. Geographically locating a client is used when users roam outside
of their home network.
In order to provide routing to off-net clients, the Service Router communicates with a Geo-Location
server, which maps IP addresses to a geographic location. For redundancy, the Internet Streaming CDSM
can be configured with a primary and secondary Geo-Location server.
The Geo-Location Server identifies the geographical location of an off-net client by the latitude and
longitude of the client. The Service Router compares the client’s location with the location of the Service
Engines participating in that delivery service and chooses the best Service Engine to serve the content.
Service Aware Routing
Note This is a Release 2.2 feature. Service aware routing is always enabled and is not configurable.
In service aware routing, the Service Router redirects the request to the Service Engine that has the
required protocol engine enabled, the required protocol engine is functioning properly and has not
exceeded its threshold, and the SE has not exceeded its thresholds as configured. See the “Setting Service
Monitor Thresholds” section on page 4-77 for more information.
When a request reaches the Service Router, the Service Router generates a hash from the URI. The
Service Router first generates a list of Service Engines to best serve the request based on service aware
routing. The Service Router then reorders the list based on the hash and selects the best Service Engine.
Because the hash generated for the same URI is equal, typically the same Service Engine is selected. If
the Service Engine is overloaded, the next Service Engine in the list is selected.
Note For service aware routing, some of the services running on a Service Engine are protocol based. When
protocol-based services associated with a protocol engine are stopped on a Service Engine, the Service
Router excludes this Service Engine from the list of possible Service Engines that can serve requests for
this type of content. The Service Router identifies the protocol engine that will serve the request based
on the user-agent in the request. For example, if some Windows Media Engine-related services are
stopped, the Service Engine can still serve Web Engine requests. However, if the request for Web Engine
content is sent from a Windows Media Player, the Service Router excludes the Service Engine from the
list of possible Service Engines that can serve the request.
Note For service aware routing, when a threshold is exceeded for all Service Engines, the Service Engine
redirects the client request to the origin server if an alternate domain is not configured. If an alternate
domain is configured, the alternate domain takes precedence. For a managed-live URL, if the origin
server does not match the source of the live program, the above case fails. For the above case to work,
the origin server host must be configured to match the live program source. In addition, the origin server
stream name must be the same as the live program name.
Content-Based Routing
Note This is a Release 2.2 feature.