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
Note In Release 2.2, the keepalive messages between the Service Router and Service Engine are transmitted
and received on port 2323. However, the Release 2.2 software interoperates with older software releases
that do not use port 2323 for keepalive messages. If a firewall is configured between the Service Engine
and the Service Router, port 2323 (UDP) must be opened for the keepalive message to go through.
Simplified Hybrid Routing
Note This feature is supported only in Releases 2.0 and 2.1.
The Service Router uses simplified hybrid routing to route requests to Service Engines. In simplified
hybrid routing, the Service Engines are chosen in a round-robin fashion if multiple Service Engines are
serving the client network region.
Load-Based Routing
Note This is a Release 2.0 and Release 2.1 feature. In Release 2.2 and later, load-based routing is enabled by
default and cannot be disabled.
If load-based routing is enabled, the routing decision is made according to the capacity and load of the
Service Engines instead of selecting the Service Engines in a round-robin fashion. This routing method
is enabled by default.
The load of the Service Engine is determined by different parameters, such as processor use, memory
usage, disk usage, the number of current Windows Media streams being served, and so on. The current
load is compared with the thresholds configured for the Service Engine. If a threshold has been exceeded
for a Service Engine it is excluded from the routing table.
Last-Resort Routing
Last-resort routing is applicable when load-based routing is enabled and all Service Engines have
exceeded their thresholds or all Service Engines in the domain are offline. The Service Router can
redirect requests to a configurable alternate domain when all Service Engines serving a client network
region are overloaded.
Last-resort routing works dynamically when Service Engines are overloaded or deactivated. When the
load of one or more Service Engines in the original host domain is reduced below threshold limits or the
Service Engines are reactivated, new requests are routed to the original host domain automatically.
If a last-resort domain is not configured and the Service Engine thresholds are exceeded, requests are
redirected to the origin server.
Last-resort routing supports requests from RTSP, HTTP (including MMS-over-HTTP), and RTMP
clients.
Location-Based Routing
Location-based routing is used for off-net clients. Off-net clients are clients that are not directly
connected to the service provider’s network. Location-based routing is designed to work with load-based
routing. When both are enabled, the Service Router first looks up the client’s IP address in the Coverage
Zone file. Then, if there is no subnet match, the client’s geographical location is compared to the