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
Resiliency and Redundancy
A CDS that is designed with full redundancy and no single point of failure includes redundant Internet
Streaming CDSMs and Service Routers. The redundancy mechanisms for the Content Acquirer and
Internet Streamer applications running on the Service Engines operate differently.
Content Acquirer Redundancy
In the event of a primary failure on the Content Acquirer, the failover mechanism supports the election
of a backup Content Acquirer. A failover requires that both the primary and backup Content Acquirer
be located in the root location of the delivery service.
Live Programs
If the Content Acquirer receives a live program as a multicast stream from the origin server, upon failure
of the primary, the backup Content Acquirer assumes control of that program’s streaming and the
program continues without interruption. This process is transparent to the end user. When the primary
Content Acquirer comes back online, it receives the live stream from the active secondary Content
Acquirer and does not fall back (regain its primary status) until the live program has finished or has been
restarted.
If the Content Acquirer receives the program as a unicast stream from the origin server, the failover
mechanism is not supported. If the primary Content Acquirer fails while a program is playing, the person
viewing the program must re-request the program.
Internet Streamer Redundancy
If a Service Engine running the Internet Streamer application fails, the Service Router stops receiving
keep-alive messages from that Service Engine. When a new request comes in, the Service Router does
not redirect the request to that Service Engine; instead, it redirects the request to other Service Engines
within the same delivery service. All the existing sessions on the failed Service Engine terminate and the
affected end users must re-request the content.
Service Router Redundancy
If the CDS network is designed with multiple Service Routers, all Service Routers are aware of all
Service Engines in the CDS. The DNS servers must be configured with multiple Service Routers and the
failover is handled by the DNS servers.
Internet Streaming CDSM Redundancy
The Internet Streaming CDSM can operate in two different roles: primary and standby. The primary role
is the default. There can only be one primary active in the CDS network; however, you can have any
number of Internet Streaming CDSMs operating in standby to provide redundancy and failover
capability.
Primary and standby CDSMs must be running the same version of software. We recommend that the
standby CDSM be upgraded first, followed by the primary CDSM.
The Internet Streaming CDSM design principle is that the management device is never in the service
delivery path. When the CDSM fails, the rest of the CDS continues to operate. A CDSM failure does not
affect any services delivered to end users, and all content ingest continues. The only negative effect is