Cabletron Systems CyberSWITCH HSIM-W6 User manual

HSIM-W6
Installation Guide
WIDE AREA1 WIDE AREA2 HSIM-W6
TELCO
TELCO
CPU
LNK
STS
LNK
STS
LNK
STS
ASYNC
9032694

HSIM-W6 Installation Guide i
Notice
Cabletron Systems reserves the right to make changes in specifications and other information contained in this document without prior
notice. The reader should in all cases consult Cabletron Systems to determine whether any such changes have been made.
The hardware, firmware, or software described in this manual is subject to change without notice.
IN NO EVENT SHALL CABLETRON SYSTEMS BE LIABLE FOR ANY INCIDENTAL, INDIRECT, SPECIAL, OR
CONSEQUENTIAL DAMAGESWHATSOEVER (INCLUDING BUT NOT LIMITED TO LOST PROFITS)ARISING OUT OF OR
RELATED TO THIS MANUAL OR THE INFORMATION CONTAINED IN IT, EVEN IF CABLETRON SYSTEMS HAS BEEN
ADVISED OF, KNOWN, OR SHOULD HAVE KNOWN, THE POSSIBILITY OF SUCH DAMAGES.
 1998 by Cabletron Systems, Inc., P.O. Box 5005, Rochester, NH 03866-5005
All Rights Reserved
Printed in the United States of America
Part Number: 9032694 June 1998
Cabletron Systems , LANVIEW , QuickSET , and SPECTRUM are registered trademarks, and HSIM is a trademark of
Cabletron Systems, Inc.
All other product names mentioned in this manual may be trademarks or registered trademarks of their respective companies.
FCC Notice
This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) this device may not cause
harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired
operation.
NOTE: This equipment has been tested and found to comply with the limits for a Class A 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 uses, generates, and can radiate radio frequency energy and if not installed in accordance
with the operator’s manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area
is likely to cause interference in which case the user will be required to correct the interference at his own expense.
WARNING: Changes or modifications made to this device which are not expressly approved by the party responsible for compliance
could void the user’s authority to operate the equipment.
Only qualified personnel should perform installation procedures.

Notice
ii HSIM-W6 Installation Guide
Industry Canada Notice
This digital apparatus does not exceed the ClassA limits for radio noise emissions from digital apparatus set out in the Radio
Interference Regulations of the Canadian Department of Communications.
Le présent appareil numérique n’émet pas de bruits radioélectriques dépassant les limites applicables aux appareils numériques de la
class A prescrites dans le Règlement sur le brouillage radioélectrique édicté par le ministère des Communications du Canada.
VCCI Notice
This is a Class A product based on the standard of the Voluntary Control Council for Interference by Information Technology
Equipment (VCCI). If this equipment is used in a domestic environment, radio disturbance may arise. When such trouble occurs, the
user may be required to take corrective actions.
Cabletron Systems, Inc. Program License Agreement
IMPORTANT: Before utilizing this product, carefully read this License Agreement.
This document is an agreement between you, the end user, and Cabletron Systems, Inc. (“Cabletron”) that sets forth your rights and
obligations with respect to the Cabletron software program (the “Program”) contained in this package. The Program may be contained
in firmware, chips or other media. BY UTILIZING THE ENCLOSED PRODUCT,YOUAREAGREEINGTO BECOME BOUND BY
THE TERMS OF THIS AGREEMENT, WHICH INCLUDES THE LICENSE AND THE LIMITATION OF WARRANTY AND
DISCLAIMER OF LIABILITY. IFYOU DO NOT AGREE TO THE TERMS OF THIS AGREEMENT, PROMPTLY RETURN THE
UNUSED PRODUCT TO THE PLACE OF PURCHASE FOR A FULL REFUND.
Cabletron Software Program License
1. LICENSE. You have the right to use only the one (1) copy of the Program provided in this package subject to the terms and
conditions of this License Agreement.
You may not copy, reproduce or transmit any part of the Program except as permitted by the CopyrightAct of the United States or
as authorized in writing by Cabletron.
2. OTHER RESTRICTIONS. You may not reverse engineer, decompile, or disassemble the Program.
3. APPLICABLE LAW. This License Agreement shall be interpreted and governed under the laws and in the state and federal courts
of New Hampshire. You accept the personal jurisdiction and venue of the New Hampshire courts.

Notice
HSIM-W6 Installation Guide iii
Exclusion of Warranty and Disclaimer of Liability
1. EXCLUSION OF WARRANTY. Except as may be specifically provided by Cabletron in writing, Cabletron makes no warranty,
expressed or implied, concerning the Program (including its documentation and media).
CABLETRON DISCLAIMS ALL WARRANTIES, OTHER THAN THOSE SUPPLIED TOYOU BY CABLETRON IN
WRITING, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, WITH RESPECT TO THE PROGRAM, THE
ACCOMPANYING WRITTEN MATERIALS, AND ANY ACCOMPANYING HARDWARE.
2. NO LIABILITY FOR CONSEQUENTIAL DAMAGES. IN NO EVENT SHALL CABLETRON OR ITS SUPPLIERS BE
LIABLE FOR ANY DAMAGES WHATSOEVER (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF
BUSINESS, PROFITS, BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, SPECIAL, INCIDENTAL,
CONSEQUENTIAL, OR RELIANCE DAMAGES, OR OTHER LOSS) ARISING OUT OF THE USE OR INABILITY TO USE
THIS CABLETRON PRODUCT, EVEN IF CABLETRON HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES. BECAUSE SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR
CONSEQUENTIAL OR INCIDENTAL DAMAGES, OR ON THE DURATION OR LIMITATION OF IMPLIED
WARRANTIES, IN SOME INSTANCES THE ABOVE LIMITATIONS AND EXCLUSIONS MAY NOT APPLY TO YOU.
United States Government Restricted Rights
The enclosed product (a) was developed solely at private expense; (b) contains “restricted computer software” submitted with restricted
rights in accordance with Section 52227-19 (a) through (d) of the Commercial Computer Software - Restricted Rights Clause and its
successors, and (c) in all respects is proprietary data belonging to Cabletron and/or its suppliers.
For Department of Defense units, the product is licensed with “Restricted Rights” as defined in the DoD Supplement to the Federal
Acquisition Regulations, Section 52.227-7013 (c) (1) (ii) and its successors, and use, duplication, disclosure by the Government is
subject to restrictions as set forth in subparagraph (c) (1) (ii) of the Rights in Technical Data and Computer Software clause at
252.227-7013. Cabletron Systems, Inc., 35 Industrial Way, Rochester, New Hampshire 03867-0505.

Notice
iv HSIM-W6 Installation Guide
Declaration of Conformity
Application of Council Directive(s): 89/336/EEC
73/23/EEC
91/263/EEC
Manufacturer’s Name: Cabletron Systems, Inc.
Manufacturer’s Address: 35 Industrial Way
PO Box 5005
Rochester, NH 03867
European Representative Name: Mr. J. Solari
European Representative Address: Cabletron Systems Limited
Nexus House, Newbury Business Park
London Road, Newbury
Berkshire RG13 2PZ, England
Conformance to Directive(s)/Product Standards: EC Directive 89/336/EEC
EC Directive 73/23/EEC
EC Directive 91/263/EEC
EN 55022
EN 50082-1
EN 60950
Equipment Type/Environment: Networking Equipment, for use in a Commercial or Light Industrial
Environment.
We the undersigned, hereby declare, under our sole responsibility, that the equipment packaged with this notice conforms to the
above directives.
Manufacturer Legal Representative in Europe
Mr. Ronald Fotino Mr. J. Solari
___________________________________ ___________________________________
Full Name Full Name
Principal Compliance Engineer Managing Director - E.M.E.A.
___________________________________ ___________________________________
Title Title
Rochester, NH, USA Newbury, Berkshire, England
___________________________________ ___________________________________
Location Location

HSIM-W6 Installation Guide v
Contents
CHAPTER 1 INTRODUCTION
Structure of this Guide.....................................................................................1-1
Related Documents..........................................................................................1-2
Document Conventions...................................................................................1-2
Getting Help......................................................................................................1-3
CHAPTER 2 ABOUT THE HSIM-W6
HSIM-W6 Hardware...........................................................................................2-1
WAN Connection........................................................................................2-1
Additional Features ...................................................................................2-3
Remote Management Capabilities..................................................................2-3
Optional Feature...............................................................................................2-4
HSIM-W6 Firmware Support............................................................................2-4
WAN Protocols...........................................................................................2-4
Inverse Multiplexing ..................................................................................2-6
Firmware Data Compression ....................................................................2-6
HDLC...........................................................................................................2-7
DHCP and NAT...........................................................................................2-7
Frame Relay Protocol................................................................................2-8
Point-to-Point Protocol..............................................................................2-9
PAP and CHAP Security............................................................................2-9
LQM...........................................................................................................2-10
Multilink Protocol.....................................................................................2-10
ISDN ..........................................................................................................2-11
ISDN Back-up ...........................................................................................2-12
The IP-OSPF Routing Protocol...............................................................2-12
IP-OSPF Hierarchy...................................................................................2-13
HDSL .........................................................................................................2-15
Bridging and Routing ..............................................................................2-15
Bridging and Routing Protocol Filtering................................................2-17

Contents
vi HSIM-W6 Installation Guide
System Passwords ..................................................................................2-17
Simple Network Management Protocol (SNMP)....................................2-18
Software and Firmware Upgrades..........................................................2-21
CHAPTER 3 INSTALLATION
Unpacking the HSIM-W6 ..................................................................................3-1
Guidelines for Installations .............................................................................3-1
Installing Interface Modules ............................................................................3-2
Installing WAN Port Interface Modules (WPIMs) ...........................................3-2
CSX-COMP/ENCR Installation.........................................................................3-4
Installing an HSIM.............................................................................................3-6
Installing an HSIM in an Interface Module...............................................3-6
Installing an HSIM in a SmartSWITCH Chassis.......................................3-9
CHAPTER 4 TROUBLESHOOTING
Troubleshooting HSIM-W6 Hardware .............................................................4-5
Power (PWR) LED is OFF..........................................................................4-5
Processor (CPU) LED is OFF....................................................................4-5
Processor (CPU) LED is RED....................................................................4-6
ASYNC Console Connection...........................................................................4-6
Link (LNK) LED is OFF...............................................................................4-6
Link (LNK) LED is RED or GREEN............................................................4-6
Link (LNK) LED is AMBER.........................................................................4-6
Status (STS) LED is OFF ...........................................................................4-6
Status (STS) LED is AMBER .....................................................................4-6
Status (STS) LED is GREEN or GREEN (Blinking)..................................4-6
Status (STS) LED is AMBER (Blinking)....................................................4-7
Troubleshooting the WAN ...............................................................................4-7
Link (LNK) LED is OFF...............................................................................4-7
Link (LNK) LED is RED..............................................................................4-7
Link (LNK) LED is AMBER.........................................................................4-7
Status (STS) LED is OFF ...........................................................................4-8

Contents
HSIM-W6 Installation Guide vii
Status (STS) LED is RED...........................................................................4-9
Status (STS) LED is AMBER .....................................................................4-9
Status (STS) LED is AMBER (blinking)..................................................4-10
Status (STS) LED is GREEN....................................................................4-10
Investigating Software Configuration Problems .........................................4-11
Connection to Device Fails During Software Configuration................4-11
User Cannot Communicate with Remote Network Station..................4-11
Troubleshooting the Frame Relay Connection.....................................4-12
APPENDIX A WPIM CABLE SPECIFICATIONS
WPIM-T1 ...........................................................................................................A-1
WPIM-SY...........................................................................................................A-3
EIA-449.......................................................................................................A-4
V.35.............................................................................................................A-5
EIA-232.......................................................................................................A-7
X.21.............................................................................................................A-8
EIA-530, EIA-530 ALT A, EIA-530 A, and EIA-530 A ALT A.................... A-9
WPIM-DDS...................................................................................................... A-11
WPIM-E1 .........................................................................................................A-12
WPIM-DI.......................................................................................................... A-14
WPIM-HDSL....................................................................................................A-15
WPIM-S/T........................................................................................................ A-16
APPENDIX B SPECIFICATIONS AND STANDARDS COMPLIANCE
Regulatory Compliance .................................................................................. B-1
Individual WPIM Regulatory Compliance......................................................B-2
WPIM-TI......................................................................................................B-2
WPIM-SY ....................................................................................................B-2
WPIM-DDS..................................................................................................B-3
WPIM-E1.....................................................................................................B-3
WPIM-DI......................................................................................................B-3
WPIM-S/T....................................................................................................B-4
WPIM-HDSL ...............................................................................................B-4

Contents
viii HSIM-W6 Installation Guide
APPENDIX C NETWORK INFORMATION WORKSHEETS
APPENDIX D FCC PART 68 - USER’S INFORMATION FOR HSIM-W6
APPENDIX E GLOSSARY
INDEX

HSIM-W6 Installation Guide 1-1
1
Introduction
Welcome to the Cabletron Systems HSIM-W6 Installation Guide . This guide provides basic
configuration information, hardware specifications and troubleshooting tips for the HSIM-W6.
This document also provides guidelines for routing and bridging over Wide Area Networks
(WANs).
Structure of this Guide
This guide is organized as follows:
Chapter 1 , Introduction , details document conventions and provides information on getting help.
Chapter 2 , About the HSIM-W6 , describes the hardware components and software protocols
and features.
Chapter 3 , Installation , provides detailed installation instructions.
Chapter 4 , Troubleshooting , provides detailed troubleshooting tips using the LANVIEW LEDs
on the HSIM-W6.
Appendix A , WPIM Cable Specifications , provides part number and connector information for
WPIMs.
Appendix B , Specifications and Standards Compliance , provides hardware specifications and
safety and compliance information.
Appendix , Network Information Worksheets , provides blank network information worksheets.
Appendix D , FCC Part 68 - User’s Information For HSIM-W6 , provides instructions required
to comply with FCC Rules, Part 68.
Appendix E , Glossary , defines commonly used terms.

Chapter 1: Introduction
1-2 HSIM-W6 Installation Guide
Related Documents
Use the READ ME FIRST! document included with the HSIM-W6 to set up a computer before
beginning configuration.
Use the Cabletron Systems QuickSET Configuration Guide to configure the HSIM-W6.
Use the Cabletron Systems CyberMONITOR User’s Guide to monitor the WAN using the
CyberMONITOR graphical user interface.
Use the appropriate Cabletron Systems WPIM Local Management Guide to connect your HSIM
to a WAN using a TELNET connection.
Document Conventions
The following conventions are used throughout this guide:
NOTE
Note symbol. Calls the reader’s attention to any item of information that may be of
special importance.
TIP
Tip symbol. Conveys helpful hints concerning procedures or actions.
!
CAUTION
Caution symbol. Contains information essential to avoid damage to the equipment.
Electrical Hazard Warning symbol.Warns against an action that could result in
personal injury or death due to an electrical hazard.
WARNING
Warning symbol.Warns against an action that could result in personal injury or death.

Getting Help
HSIM-W6 Installation Guide 1-3
Getting Help
If you need additional support related to this device, or if you have any questions, comments, or
suggestions concerning this manual, contact the Cabletron Systems Global Call Center:
Before calling the Cabletron Systems Global Call Center, have the following information ready:
• Your Cabletron Systems service contract number
• A description of the failure
• A description of any action(s) already taken to resolve the problem (e.g., changing mode
switches, rebooting the unit, etc.)
• A description of your network environment (layout, cable type, etc.)
• Network load and frame size at the time of trouble (if known)
• The serial and revision numbers of all involved Cabletron Systems products in the network
• The device history (i.e., have you returned the device before, is this a recurring problem, etc.)
• Any previous Return Material Authorization (RMA) numbers
Phone [phone]
Internet mail suppor[email protected]
FTP ctron.com (134.141.197.25)
Login anonymous
Password your email address
BBS [phone]
Modem setting 8N1: 8 data bits, No parity, 1 stop bit
For additional information about Cabletron Systems or our products,
visit our World Wide Web site: http://www.cabletron.com/
For technical support, select Service and Support .

Chapter 1: Introduction
1-4 HSIM-W6 Installation Guide

HSIM-W6 Installation Guide 2-1
2
About the HSIM-W6
The HSIM-W6 ( Figure 2-1 ) offers high-speed Wide Area Network (WAN) access to remote sites
via two WAN Port Interface Modules (WPIMs) to the device into which it is installed. The
HSIM-W6 supports IEEE 802.1d transparent bridging, IP routing, IPX routing between the host
device and the two WAN connections, ISDN, Dynamic Host Configuration Protocol (DHCP),
Network Address Translation (NAT), and Inverse Multiplexing (IMUX) between Ethernet LANs
across a WAN resource. In addition, the ASYNC port connector can be used as a local console
connection.
Figure 2-1 The HSIM-W6
HSIM-W6 Hardware
This section details the HSIM-W6 hardware capabilities.
WAN Connection
The HSIM-W6 supports Point-to-Point Protocol (PPP) including: Link Control Protocol (LCP),
BNCP, IPCP, IPXCP, LQM, Multilink Protocol (MP) and CHAP and PAP, ISDN-BRI and Frame
Relay protocols through one of the following WAN port interface modules (WPIMs):
• The WPIM-T1 provides a T1 interface through a front panel RJ45 port and includes a built-in
Channel Service Unit/Digital Service Unit (CSU/DSU) for direct connection to a T1 line. The
WPIM-T1 provides both Full T1 or Fractional T1 using 56 or 64 Kbps timeslots, with a total
throughput of up to 1.544 Mbps.
WIDE AREA1 WIDE AREA2 HSIM-W6
225700
TELCO
TELCO
CPU
LNK
STS
LNK
STS
LNK
STS
ASYNC

Chapter 2: About the HSIM-W6
2-2 HSIM-W6 Installation Guide
• The WPIM-SY provides a synchronous serial connection of up to 2.048 Mbps to external
communications equipment (e.g., a multiplexer or CSU/DSU). The WPIM-Sync uses a
subminiature 26-pin connector that supports the following electrical signal interfaces:
•EIA-RS449
•V.35
•EIA-RS232D
•X.21
•EIA-RS530
•EIA-530A
•RS530 ALT A
•RS530A ALT A
•The WPIM-DDS provides a 56 Kbps or 64 Kbps Digital Data Service (DDS) connection. The
WPIM-DDS supports remote CSU diagnostic or 64 Kbps clear channel loopback and
non-latching remote DSU diagnostic loopback.
•The WPIM-E1 provides an E1 interface through a front panel RJ45 port and includes a built-in
CSU/DSU for direct connection to an E1 line. The WPIM-E1 provides both Full E1 or
Fractional E1 using 56 or 64 Kbps timeslots with a total throughput of up to 2 Mbps.
•The WPIM-DI provides a T1 interface through a front panel RJ45 port and includes a built-in
CSU/DSU for direct connection to a T1 line.TheWPIM-DI provides both FullT1 or Fractional
T1 using 56 or 64 Kbps timeslots and also provides a second Drop-and-Insert interface, which
allows more than one device to share a single T1 connection.
•The WPIM-S/T provides an Integrated Services Digital Network (ISDN) 128 Kbps Basic Rate
Interface (BRI) for the HSIM-W6.The WPIM-S/T provides an ISDN back-up link for a remote
site or branch office when the main WPIM for a frame relay or leased line loses a connection
or becomes disabled. An NT-1 adapter is necessary for this interface in the United States.
•The WPIM-HDSL provides a connection for users in a campus environment, or have access to
local subscriber loops, who want to send their data over their existing telephone lines, that may
run between floors, buildings, or other physical structures, at rates of up to 1.544 Mbps. HDSL
supports line lengths of up to 3, 657 meters (12,000 feet) over 24AWG (American Wire Gauge)
Unshielded Twisted Pair (UTP) cabling.

Remote Management Capabilities
HSIM-W6 Installation Guide 2-3
•The WPIM-T1/DDS provides both a T1 and DDS interface that allows changing between the
two interfaces by switching the physical cabling and reconfiguring QuickSET for the desired
interface. The WPIM-T1/DDS has the capabilities of both the WPIM-T1 and WPIM-DDS.
Additional Features
FLASH EEPROMs — The HSIM-W6 uses FLASH Electrically Erasable Programmable
Read-Only Memory (EEPROM) that allows the downloading of new and updated firmware in
conjunction with Cabletron Systems QuickSET or any device using BootP or TFTP protocols.
LANVIEW LEDs — Cabletron Systems LANVIEW Status Monitoring and Diagnostics System is
a troubleshooting tool that helps in the diagnosing of power failures, collisions, cable faults, and
link problems. The LANVIEW LEDs are located on the HSIM-W6 front panel.
Remote Management Capabilities
The HSIM-W6 can be remotely managed with any SNMP network management system including
the following:
•Cabletron Systems SPECTRUM for Open Systems Suite of Network Management Products
•Cabletron Systems QuickSET
•Third Party SNMP compliant Network Management Packages

Chapter 2: About the HSIM-W6
2-4 HSIM-W6 Installation Guide
Optional Feature
Hardware Data Compression Module (CSX-COMP/ENCR) — The same industry standard
STAC Electronics Stacker LZS Compression algorithm supported by HSIM-W6 software is made
available by an optional hardware data compression module that accelerates data compression for
the HSIM-W6 over Nailed-up PPP or ISDN and Frame Relay. Depending on the packet type and
size, hardware data compression provides a minimum of 2:1 data compression, giving 3 Mbps
throughput on each T-1 WPIM interface. To use the hardware data compression module,
compatible equipment (such as the HSIM-W6, CSX200, and CSX400 or other vendors’
equipment which conforms to the applicable standards) must be in use at both ends of the WAN
link. When the hardware data compression module is installed on the board, it automatically
assumes the compression task from software. There is no configuration necessary to prioritize
hardware over software compression.
HSIM-W6 Firmware Support
The HSIM-W6 firmware supports IEEE 802.1d bridging, and IP and IPX routing, and OSI Layer 2
Inverse Multiplexing (IMUX), which allows both WAN channels to be used as a single, high
bandwidth, WAN channel. Wide Area Networking includes Point-to-Point Protocol (PPP), Frame
Relay, and ISDN. Remote access is via Full or Fractional T1, E1, Synchronous, Digital Data
Service, ISDN BRI, or HDSL connections.
This device supports industry-standard protocols, security features, compression algorithms and
network management tools to ensure interoperability with equipment from other vendors.
WAN Protocols
This device supports the following WAN protocols over the WAN port:
•Point-to-Point Compression Control Protocol (CCP) as defined by RFC 1962
•Point-to-Point Protocol (LCP) as defined by RFC 1661
•Point-to-Point Protocol (BNCP) as defined by RFC 1638
•Point-to-Point Protocol (IPCP) as defined by RFC 1473
•Point-to-Point Protocol (IPXCP) as defined by RFC 1552
•Frame Relay as defined by RFC 1490
•Frame Relay Data Compression Protocol (DCP) as defined by FRF.9

HSIM-W6 Firmware Support
HSIM-W6 Installation Guide 2-5
•Inverse Multiplexing (IMUX)
•Dynamic Host Configuration Protocol (DHCP) as defined by RFC 1541
•Network Address Translation (NAT) routing as defined by RFC 1631
•Password Authentication Protocol (PAP) and Challenge Handshake Authentication Protocol
(CHAP) under PPP as defined by RFC 1994
•Point-to-Point Protocol Link Quality Monitoring (LQM) as defined by RFC 1333
•Point-to-Point Protocol Multilink Protocol (MP) as defined by RFC 1990
•Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) as defined by Q.921/
Q.931
•Frame Relay Link Management Interface (LMI) as defined byANSI T1.617Annex D and ITU
Q.933 Annex A
•Frame Relay Data Encapsulation as defined by RFC 1490
•Frame Relay Data Compression Protocol (DCP) as defined by FRF.9
PPP is a data link layer industry standard WAN protocol for transferring multi-protocol data traffic
over point-to-point connections. With this protocol, options such as security, data compression,
and network protocols can be negotiated over the connection.
Frame Relay is a packet-switching data communications protocol that statistically multiplexes
many data conversations over a single transmission link. Data compression allows Frame Relay to
negotiate compression over Frame Relay permanent virtual circuits (PVCs).
ISDN BRI is a switched Data Link layer control protocol which uses digital signaling to place a
call into an ISDN network. Once the call is made, PPP is then used to transfer data.

Chapter 2: About the HSIM-W6
2-6 HSIM-W6 Installation Guide
Inverse Multiplexing
Cabletron Systems Inverse Multiplexing (IMUX) feature provides enhanced throughput for users
by doing each of the following:
•The IMUX function evenly distributes a data packet stream from the LAN interface through the
twoWAN interfaces on the HSIM-W6. Since the data traffic is equally shared between the two
Full T1 interfaces, each with 1.5 Mbps throughput, the total throughput over the logical link is
3 Mbps, or 6 Mbps full-duplex operation with the optional hardware compression module
(CSX-COMP/ENCR) installed in the HSIM-W6.
•TheIMUX function passespacketsequenceinformationovertheWAN usingthePoint-to-Point
Protocol (PPP) to support data coherency on both ends of the link.
•Data packet streams received by the WAN interfaces on the other end of theWAN link are then
recombined, ordered, and transmitted to the LAN interface.
•The IMUX function is fully configurable using QuickSET, which is discussed in the
QuickSet Configuration Guide.
Firmware Data Compression
The STAC Electronics Stacker LZS Compression algorithm provides a minimum of 2:1 firmware
data compression for the HSIM-W6 over PPP and Frame Relay. Firmware data compression is
supported in software on each WAN interface for line speeds of up to 256 Kbps per WPIM, which
is equivalent to four DS0 channels. To use data compression, compatible equipment, (such as the
HSIM-W6, CSX400, and CSX200 or other vendors’equipment which conforms to the applicable
standards), must be in use at both ends of the WAN link. This firmware method of data
compression is used as the default, if the hardware compression module is not installed.
NOTE Cabletron Systems products that support Inverse Multiplexing (IMUX), such as the
HSIM-W6, CSX400, and HSIM-W84, must exist on both ends of the WAN link for the
IMUX function to work.
Both bridging and routing functions are disabled when using the IMUX function.