Cisco 7246VXR - uBR Router Software Configuration Manual page 162

DOCSIS and CMTS Interoperability
Parameters to determine the over-subscription level include:
Peak percentage of simultaneous users—Not all subscribers access the network at the same time.
•
Subscribers have different access patterns that vary based on profiles; working hours; family
demographics; type of user—telecommuter or residential Internet access customer. Only a portion
of subscribers are active at a given time. This number serves as the "peak percentage of simultaneous
users parameter"— busy hour number of subscribers.
Average data rate per subscriber—Not only are all subscribers not active at the same time, but they
•
do not continuously operate at peak rate. Using basic Internet access as an application, data that
subscribers request and send downstream and upstream is burst-intensive. A group of subscribers,
therefore, has an average data rate less than the maximum rate defined by the service.
Note For some services, the average value might be the maximum rate. VoIP is such an application.
How bandwidth contention is handled depends on the mix of services defined and individual service
definitions.
Percentage of homes passed subscribing to the service is another factor to consider. If this parameter is set too
conservatively, the network is under-engineered and requires modification to grow the service. If set too
aggressively, the network is over-engineered and costs for services are higher than they should be.
Full implementation of service levels requires additional higher layer items including scheduling,
queuing priorities, bandwidth allocation. These items are addressed in DOCSIS 1.0 extensions. Refer to
the "This section summarizes Cisco uBR7200 series router software features for all supported Cisco
IOS Release trains, and directs you to additional configuration information for each feature."
follows and respective chapters of this guide for additional information.
Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide
1-144
Chapter 1 Overview of Cisco uBR7200 Series Software
section that
OL-2239-05