PairGain CRA-C Manuale utente
Megabit Modem CRA-C
User Manual
Power
10BASE-TADSL
Manual Number: 425-613-150-02
ii Megabit Modem CRA-C User Manual
Megabit Modem CRA-C User Manual
P/N 425-613-150-02
Revision 02
May 1998
Copyright © 1998. PairGain Technologies, Inc. All rights reserved.
This document contains proprietary information which is protected by
copyright.
Information contained in this document is company private to PairGain
Technologies, Inc. and shall not be modified, used, copied, reproduced or
disclosed in whole or in part without the written consent of PairGain.
PairGain is a registered trademark, and Megabit Modem is a trademark of
PairGain Technologies, Inc.
Other product names mentioned in this manual are used for identification
purposes only and may be trademarks and/or registered trademarks of their
respective companies.
The information in this publication is believed to be accurate in all respects.
However, PairGain Technologies cannot assume responsibility for any
consequences resulting from the use thereof. The information contained herein
is subject to change. Revision to this publication or new additions to it may be
issued to incorporate such changes.
Megabit Modem CRA-C User Manual iii
FCC NOTICE
This equipment has been tested and found to comply with the limits for a
Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference when
the equipment is operated in a commercial environment. This equipment
generates, uses, and can radiate radio frequency energy and, if not installed and
used in accordance with this instruction manual, may cause harmful
interference to radio communication.
However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off
and on, the user is encouraged to try to correct the interference by one or more
of the following measures:
•Reorient or relocate the receiving antenna.
•Increase the separation between the equipment and receiver.
•Connect the equipment into an outlet on a circuit different from that
to which the receiver is connected.
•Consult the dealer or an experienced radio/TV technician for help.
Any changes or modifications not expressly
approved by the grantee of this device voids
the user’s authority to operate the equipment.
iv Megabit Modem CRA-C User Manual
DECLARATION OF CONFORMITY
Manufacturer’s name PairGain Technologies, Inc.
and address: 14402 Franklin Ave
Tustin, CA 92780-7013
U.S.A.
declares that
Product name: Megabit Modem CRA-C
conforms to the following
Standards: EN55022 (1987), EN50082-1 (1992),
EN60950 (1994)
Application of Council Directives: 89/336/EEC, 73/23/EEC
I, the undersigned, hereby declare that the equipment specfied above conforms
to the above directives and standards.
Signature:
Roy Stephens,
Director of Quality Assurance
Place: Tustin, CA, U.S.A.
Date: March 16, 1998
Megabit Modem CRA-C User Manual v
USING THIS MANUAL
This manual helps you:
•understand the features of the PairGain®Megabit Modem™ CRA-C
and how the unit operates as a component within a network
•install the Megabit Modem CRA-C
•configure your unit to operate within the network
•contact PairGain if you need additional help
Three types of messages with icons appear in the text:
Notes inform you of special circumstances.
Cautions indicate the possibility of damage to equipment.
Warnings indicate the possibility of personal injury.
Using This Manual
vi Megabit Modem CRA-C User Manual
Megabit Modem CRA-C User Manual vii
CONTENTS
ABOUT THE MEGABIT MODEM CRA-C __________________ 1
About Rate Adaptive Transmission.....................................2
Rate Adaptation..............................................................2
Reach, Data Rate, SNR Margin,
and Noise Environment............................................ 4
INSTALL THE MEGABIT MODEM CRA-C_________________ 7
Unpack and Inspect the Shipment.......................................7
Identify LEDs and Connectors............................................ 9
Front Panel..................................................................... 9
Rear Panel.................................................................... 11
Install the Megabit Modem CRA-C .................................. 12
Connect to the ADSL Line ...........................................12
Connect to the Data Network........................................ 13
Power Up and Check LEDs ..............................................16
CONFIGURE AND VIEW STATUS________________________ 17
Connect to an ASCII Terminal.......................................... 17
How to Log On and Navigate the Menus .......................... 19
How to Configure a Remote Unit...................................... 23
Configure System Settings................................................ 24
Configure ADSL Transceiver ...........................................26
Configuration ............................................................... 26
Reset ADSL Transceiver .............................................. 29
Configure the Bridge/Router............................................. 30
Configure as a Bridge................................................... 31
Configure as a Router................................................... 34
Configure SNMP.......................................................... 38
Reset the Ethernet Bridge............................................. 40
View Status ...................................................................... 41
System Information ...................................................... 41
ADSL Transceiver Status.............................................. 42
Ethernet Bridge Statistics.............................................. 48
Log Out............................................................................ 49
Contents
viii Megabit Modem CRA-C User Manual
NETWORK AND MANAGEMENT OVERVIEW____________ 51
MAC Layer Bridging and Spanning Tree Protocol............51
Static IP Routing...............................................................53
Megabit Modem CRA-C IP Addresses..........................59
Management Protocols......................................................61
SNMP...........................................................................61
Megabit Modem CRA-C SNMP Agent .........................62
MIB and Trap Support..................................................63
Network Configuration and Image Code Download ..........64
BOOTP.........................................................................64
TFTP ............................................................................66
Encapsulation Protocols....................................................66
TECHNICAL SPECIFICATIONS _________________________ 67
TECHNICAL ASSISTANCE______________________________ 69
World-Wide Web..............................................................69
FTP ..............................................................................69
LIMITED WARRANTY _________________________________ 71
GLOSSARY____________________________________________ 73
Megabit Modem CRA-C User Manual 1
ABOUT THE MEGABIT MODEM CRA-C
The PairGain®Megabit Modem™ CRA-C uses Asymmetric Digital
Subscriber Line (ADSL) technology to provide, on a single pair telephone line,
a multi-megabit Ethernet connection between the subscriber and the service
provider. The Megabit Modem CRA-C transmits data up to 3.16 Mbps from a
service provider and receives data up to 1.08 Mbps from a subscriber. The
Megabit Modem CRA-C is rate adaptive; its speed is adjusted to the maximum
attainable data rate depending on distance and line condition. Additionally,
ADSL technology allows ordinary telephone service to coexist with the
high-speed data service on the same wire pair.
The rate-adaptive Megabit Modem allows the service provider to deliver the
best possible data rate for any subscriber. Typically, a subscriber closest to the
provider receives the highest data rate available, while subscribers farther
away receive data at a lower transmission rate.
The Megabit Modem CRA-C has field-proven Carrierless
Amplitude-modulation and Phase-modulation (CAP) line coding.
The 2-dimensional, 8-state Trellis coding with Viterbi decoding and
the Reed-Solomon forward-error-correction provide robust transmission
in harsh environments.
Use the Megabit Modem CRA-C for application solutions, particularly those
requiring high-speed transmission to the subscriber, such as:
Internet access
remote Local Area Network (LAN) access
telecommuting
•small office or home office
Other features of the Megabit Modem CRA-C include:
embedded Simple Network Management Protocol (SNMP) agent
IEEE 802.1d transparent MAC level bridging with Spanning Tree
protocol support
static IP routing to provide secure access to the Internet
BOOTP and TFTP to download software
10BASE-T Ethernet port for connection to an Ethernet LAN
line port for Rate-adaptive ADSL single-pair connection
•console port for maintenance and management
About the Megabit Modem CRA-C
2 Megabit Modem CRA-C User Manual
Use the Megabit Modem CRA-C with these other PairGain products:
•Megabit Modem CRA (at subscriber site)
•S1 Network Interface Device (network interface at subscriber site)
About Rate Adaptive Transmission
The following definitions are useful for understanding the operation of the
Megabit Modem:
•Bit Error Rate (BER) is the ratio of received bits that are in error
relative to the total number of bits received, measured over time.
For example, 10-7 BER means that on average one error occurs per
107bits received.
•Signal to Noise Ratio (SNR) is the ratio (typically expressed in dB) of
the received signal power to the received noise power. It is a measure
of the quality of the transmission. The theoretically achievable BER
can be extrapolated from the measured SNR.
•Margin (SNR margin) is the amount of degradation in SNR that the
system can tolerate under the current conditions and still achieve a
10-7 BER. A margin of 6 dB, for example, would mean that the SNR
can degrade by 6 dB and still provide a performance of 10-7 BER. The
PairGain Megabit Modem CRA-C has a margin configuration option
that defaults to 6 dB, but may be set anywhere between -3 dB to 9 dB.
•Reach is the longest loop length that the system can support with
a given margin and a BER of less than 10-7 at the given data rate.
Rate Adaptation
With PairGain's rate adaptive technology, the Megabit Modem CRA-C
can automatically adjust to the fastest speed possible, given the transmission
distance and line conditions. Alternatively, the provider can manually set
the modem to a specific rate. The available data rates are:
•downstream (transmit) rates: 3.168 Mbps, 2.528 Mbps, 2.208 Mbps,
1.888 Mbps, 1.568 Mbps, 1.248 Mbps, 928 Kbps, 608 Kbps
•upstream (receive) rates: 1.080 Mbps, 944 Kbps, 808 Kbps, 672 Kbps,
536 Kbps, 400 Kbps, 264 Kbps, 82.66 Kbps
Indice
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