Tài liệu Dynamic Reconfiguration of Indoor Combination Networks Through the Use of Patch Panels pdf

Adding radio-frequency patch panels to combination networks adds a high degree of flexibility and allows for different levels of combination without affecting network service.. Initially

Executive Summary

In terms of flexibility, the traditional combination networks found inside hubs and headends are quite rigid, making it difficult to change combination ratios Adding radio-frequency patch panels

to combination networks adds a high degree of flexibility and allows for different levels of

combination without affecting network service

Issues in Traditional Configuration Networks

Over the past few years, cable operators have encountered an unexpected problem integrating high-speed data and integrated telephony services

Initially, high-speed data and integrated telephony services were deployed using a design that assigned fixed ratios of combination between the number of homes and the controller inputs in hubs and headends For example, operators often assigned 1,000 homes to a DOCSIS upstream input for cable-modem service

As a result, it’s common to find a first splitting stage just after the optical receivers inside the hubs

in an upstream network Following the first splitting stage is a series of combination stages that group the return path of the optical nodes in ratios that vary according to the provided service

Using high-speed data as an example, these stages could result the grouping of a signal coming from eight optical nodes into one CMTS upstream input

This creates a rigid ratio structure with fixed combiners and splitters that condition the service

A clear example can be seen in the following illustration, where the number of cable-modem users has grown and the combination networks limits the number of users that can be served by the network

w w w a d c c o m • + 1 - 9 5 2 - 9 3 8 - 8 0 8 0 • 1 - 8 0 0 - 3 6 6 - 3 8 9 1

Groups of

8 Upstream Signals

Groups of

8 Upstream Signals

Groups of 32 Upstream Signals

Cable Modem Concentration Stage

Distribution Stage

Switch Opt Rec.

Opt Rec.

Opt Rec.

Opt Rec.

Opt Rec.

Opt Rec.

Switch

Switch

Integrated Telephony Concentration Stage

Conditional Access and Monitoring Concentration Stage

Alternative Through the Use of Radiofrequency Patch Panel

Necessary Situation After Growth of Penetration

In this example, subscriber penetration causes the need for change from Initial Situation to Necessary Situation It forces reengineering the network along with adding and removing devices and cabling One solution to this dilemma is to create a more flexible combination network The inclusion of patch panels provides the needed flexibility, providing for growth without negatively affecting existing cabling and devices

The following diagram illustrates how, with the addition of patch panels, an operator can change the ratio of optical nodes attached per upstream input in the CMTS, resulting in the following advantages:

• As the ratio changes, there is no effect on the fixed cabling as all the fixed cabling is on the rear side

of the patch panels

• Changes can be made without affecting service as it’s only necessary to make the change in the CMTS input

• New services and nodes can be added without affecting service

• New CMTS or Integrated Telephony cards can be added to the shelves without affecting service

CMTS Input 1

500 Users Maximum

2000 homes in

4 optical nodes

500 can be served 25% penetration

4:1

CMTS Input 1

500 Users Maximum

2000 homes in

4 optical nodes

1000 can be served 50% penetration

2:1

CMTS Input 2

500 Users Maximum 2:1

Initial Situation

Distribution Stage

Concentration Stage Opt Rec.1

Opt Rec N

Flexible with Patch Panels at Different Stages

It’s important to note that while the diagram shows the return path of the network, the same philosophy should be applied to the downstream path

CMTS 1 CMTS 2

4:1

CMTS 1

CMTS 1 CMTS 2

1 Initial Situation

Combination of 4 Nodes per Upstream Input in the CMTS

2 Temporary Change Without Affecting Service

to a Combination of 2 Nodes per Upstream Input in the CMTS

3 Final Situation

Combination of 2 Nodes per Upstream Input in the CMTS

Patch panels act as the mechanical support for the jacks The two rear connectors are bridged as the jack acts as a loop with the front connectors 75 Ohm-terminated When a jack is inserted into any of the front inputs, the corresponding rear connection is rerouted to the front and goes through the inserted jack Simultaneously, the unconnected connections are grounded to avoid RF interference

ADC Telecommunications, Inc., P.O Box 1101, Minneapolis, Minnesota USA 55440-1101 Specifications published here are current as of the date of publication of this document Because we are continuously improving our products, ADC reserves the right to change specifications without prior notice At any time, you may verify product specifications by contacting our headquarters office in Minneapolis ADC Telecommunications, Inc views its patent portfolio as an important corporate asset and vigorously enforces its patents Products or features contained herein may be covered by one or more U.S or foreign patents An Equal Opportunity Employer

Web Site: www.adc.com

From North America, Call Toll Free: 1-800-366-3891 • Outside of North America: +1-952-938-8080 Fax: +1-952-917-3237 • For a listing of ADC’s global sales office locations, please refer to our web site.

Normal Operation

Loop

Patch Operation

(Reconfiguration)

Routing Through the Front Inserted Jack