SMC Networks Barricade SMC7401BRA User manual

2-Port Broadband Router
with Built-in ADSL Modem
◆ Compatible with all leading DSLAMs
◆ Supports DMT line modulation
◆ Supports full-rate ADSL (G.992.1 & T1.413, Issue 2)
- Up to 8 Mbps downstream and 640 Kbps upstream
◆ Supports G.lite ADSL (G.992.2)
- Up to 1.5 Mbps downstream and 512 Kbps upstream
◆ Supports DSL handshaking (G.994.1)
◆ Multiple user Internet access with a single user account
◆ Plug & Play installation
◆ Web-based management
User Guide
SMC7401BRA

ADSL Router
User Guide
From SMC’s Barricade line of award-winning connectivity solutions
May 2002
PartNo: EU 750.7582, UK 750.7595
Pub No: 150000013600E R02

SMC's Limited Warranty Statement
Limited Warranty Statement: SMC Networks Europe ("SMC") warrants its
products to be free from defects in workmanship and materials, under
normal use and service, for the applicable warranty term. All SMC products
carry a standard 2 year limited warranty from the date of purchase from SMC
or its Authorised Reseller. SMC may, at its own discretion, repair or replace
any product not operating as warranted with a similar or functionally
equivalent product, during the applicable warranty term. SMC will endeavour
to repair or replace any product returned under warranty within 30 days of
receipt of the product. As new technologies emerge, older technologies
become obsolete and SMC will, at its discretion, replace an older product in
its product line with one that incorporates these newer technologies
The standard limited warranty can be upgraded to a 5 year Limited
Lifetime * warranty by registering new products within 30 days of
purchase from SMC or its Authorised Reseller. Registration can be
accomplished via the enclosed product registration card or online via the
SMC web site. Failure to register will not affect the standard limited
warranty. The Limited Lifetime warranty covers a product during the Life
of that Product, which is defined as a period of 5 years from the date of
purchase of the product from SMC or its authorised reseller.
All products that are replaced become the property of SMC. Replacement
products may be either new or reconditioned. Any replaced or repaired
product carries, either a 30-day limited warranty or the remainder of the
initial warranty, whichever is longer. SMC is not responsible for any
custom software or firmware, configuration information, or memory data
of Customer contained in, stored on, or integrated with any products
returned to SMC pursuant to any warranty. Products returned to SMC
should have any customer-installed accessory or add-on components, such
as expansion modules, removed prior to returning the product for
replacement. SMC is not responsible for these items if they are returned
with the product.
Customers must contact SMC for a Return Material Authorisation number
prior to returning any product to SMC. Proof of purchase may be
required. Any product returned to SMC without a valid Return Material
Authorisation (RMA) number clearly marked on the outside of the
package will be returned to customer at customer’s expense. Customers
are responsible for all shipping charges from their facility to SMC. SMC is
responsible for return shipping charges from SMC to customer.
LIMITED WARRANTY
i

WARRANTIES EXCLUSIVE: IF A SMC PRODUCT DOES NOT OPERATE
AS WARRANTED ABOVE, CUSTOMER'S SOLE REMEDY SHALL BE REPAIR
OR REPLACEMENT OF THE PRODUCT IN QUESTION, AT SMC’S
OPTION. THE FOREGOING WARRANTIES AND REMEDIES ARE
EXCLUSIVE AND ARE IN LIEU OF ALL OTHER WARRANTIES OR
CONDITIONS, EXPRESSED OR IMPLIED, EITHER IN FACT OR BY
OPERATION OF LAW, STATUTORY OR OTHERWISE, INCLUDING
WARRANTIES OR CONDITIONS OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE. SMC NEITHER ASSUMES NOR
AUTHORISES ANY OTHER PERSON TO ASSUME FOR IT ANY OTHER
LIABILITY IN CONNECTION WITH THE SALE, INSTALLATION,
MAINTENANCE OR USE OF ITS PRODUCTS. SMC SHALL NOT BE LIABLE
UNDER THIS WARRANTY IF ITS TESTING AND EXAMINATION
DISCLOSE THE ALLEGED DEFECT IN THE PRODUCT DOES NOT EXIST
OR WAS CAUSED BY CUSTOMER'S OR ANY THIRD PERSON'S MISUSE,
NEGLECT, IMPROPER INSTALLATION OR TESTING, UNAUTHORISED
ATTEMPTS TO REPAIR, OR ANY OTHER CAUSE BEYOND THE RANGE
OF THE INTENDED USE, OR BY ACCIDENT, FIRE, LIGHTNING, OR
OTHER HAZARD.
LIMITATION OF LIABILITY: IN NO EVENT, WHETHER BASED IN
CONTRACT OR TORT (INCLUDING NEGLIGENCE), SHALL SMC BE
LIABLE FOR INCIDENTAL, CONSEQUENTIAL, INDIRECT, SPECIAL, OR
PUNITIVE DAMAGES OF ANY KIND, OR FOR LOSS OF REVENUE, LOSS
OF BUSINESS, OR OTHER FINANCIAL LOSS ARISING OUT OF OR IN
CONNECTION WITH THE SALE, INSTALLATION, MAINTENANCE, USE,
PERFORMANCE, FAILURE, OR INTERRUPTION OF ITS PRODUCTS, EVEN
IF SMC OR ITS AUTHORISED RESELLER HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.
SOME COUNTRIES DO NOT ALLOW THE EXCLUSION OF IMPLIED
WARRANTIES OR THE LIMITATION OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES FOR CONSUMER PRODUCTS, SO THE
ABOVE LIMITATIONS AND EXCLUSIONS MAY NOT APPLY TO YOU.
THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY
VARY FROM COUNTRY TO COUNTRY. NOTHING IN THIS WARRANTY
SHALL BE TAKEN TO AFFECT YOUR STATUTORY RIGHTS.
* Under the limited lifetime warranty, internal and external power
supplies, fans, and cables are covered by a standard one-year warranty
from date of purchase.
LIMITED WARRANTY
ii

Information furnished is believed to be accurate and reliable. However, no responsibility is assumed by our
company for its use, nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of our
company. We reserve the right to change specifications at any time without notice.
Copyright © 2002 by SMC
All rights reserved. Printed in Taiwan
Trademarks:
Product and company names are trademarks or registered trademarks of their respective holders.

iii
C OMPLIANCES
FCC - Class B
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 in a residential installation. This equipment generates,
uses and can radiate radio frequency energy and, if not installed and used in accordance with
instructions, may cause harmful interference to radio communications. However, there is no
guarantee that the 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 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
Note: In order to maintain compliance with the limits for a Class B digital device, you are
required to use a quality interface cable when connecting to this device. Changes or
modifications not expressly approved by our company could void the user’s
authority to operate this equipment.
Attach unshielded twisted-pair (UTP) to the RJ-45 port and shielded USB cable to
the USB port.
FCC - Part 68
This equipment complies with Part 68 of the FCC rules. This equipment comes with a label
attached to it that contains, among other information, the FCC registration number and
ringer equivalence number (REN) for this equipment. If requested, this information must be
provided to the telephone company.
This equipment uses the following USOC jacks: RJ11C
The REN is used to determine the quantity of devices that may be connected to the
telephone line. Excessive RENs on the telephone line may result in the devices not ringing in
response to an incoming call. In most, but not all areas, the sum of the RENs should not
exceed five (5.0). To be certain of the number of devices that may be connected to the line, as
determined by the total RENs, contact the telephone company to determine the maximum
REN for the calling area.
If this equipment causes harm to the telephone network, the telephone company will notify
you in advance that temporary discontinuance of service may be required. If advance notice is
not practical, the telephone company will notify the customer as soon as possible. Also, you
will be advised of your right to file a complaint with the FCC if you believe it is necessary.

C OMPLIANCES
iv
The telephone company may make changes in its facilities, equipment, operations, or
procedures that will provide advance notice in order for you to make the necessary
modifications in order to maintain uninterrupted service.
If trouble is experienced with this equipment, please contact our company at the numbers
shown on back of this manual for repair and warranty information. If the trouble is causing
harm to the telephone network, the telephone company may request you to remove the
equipment from the network until the problem is resolved.
No repairs may be done by the customer.
This equipment cannot be used on telephone company-provided coin service. Connection to
Party Line Service is subject to state tariffs.
When programming and/or making test calls to emergency numbers:
• Remain on the line and briefly explain to the dispatcher the reason for the call.
• Perform such activities in off-peak hours such as early morning or late evenings.
The Telephone Consumer Protection Act of 1991 makes it unlawful for any person to use a
computer or other electronic device to send any message via a telephone facsimile machine
unless such message clearly contains, in a margin at the top or bottom of each transmitted
page or on the first page of the transmission the date and time it is sent and an identification
of the business, other entity, or individual sending the message and the telephone number of
the sending machine or such business, other entity, or individual.
In order to program this information into your facsimile, refer to your communications
software user manual.
Industry Canada - Class B
This digital apparatus does not exceed the Class B limits for radio noise emissions from
digital apparatus as set out in the interference-causing equipment standard entitled “Digital
Apparatus,” ICES-003 of Industry Canada.
Cet appareil numérique respecte les limites de bruits radioélectriques applicables aux appareils
numériques de Classe B prescrites dans la norme sur le matérial brouilleur: “Appareils
Numériques,” NMB-003 édictée par l’Industrie.

C OMPLIANCES
v
EC Conformance Declaration - Class B
This information technology equipment complies with the requirements of the Council
Directive 89/336/EEC on the Approximation of the laws of the Member States relating to
Electromagnetic Compatibility and 73/23/EEC for electrical equipment used within certain
voltage limits and the Amendment Directive 93/68/EEC. For the evaluation of the
compliance with these Directives, the following standards were applied:
RFI Emission: • Limit class B according to EN 55022:1998
• Limit class B for harmonic current emission according to
EN 61000-3-2/1995
• Limitation of voltage fluctuation and flicker in low-voltage supply
system according to EN 61000-3-3/1995
Immunity: • Product family standard according to EN 55024:1998
• Electrostatic Discharge according to EN 61000-4-2:1995
(Contact Discharge: ±4 kV, Air Discharge: ±8 kV)
• Radio-frequency electromagnetic field according to EN 61000-4-3:1996
(80 - 1000 MHz with 1 kHz AM 80% Modulation: 3 V/m)
• Electrical fast transient/burst according to EN 61000-4-4:1995 (AC/
DC power supply: ±1 kV, Data/Signal lines: ±0.5 kV)
• Surge immunity test according to EN 61000-4-5:1995
(AC/DC Line to Line: ±1 kV, AC/DC Line to Earth: ±2 kV)
• Immunity to conducted disturbances, Induced by radio-frequency
fields: EN 61000-4-6:1996 (0.15 - 80 MHz with
1 kHz AM 80% Modulation: 3 V/m)
• Power frequency magnetic field immunity test according to
EN 61000-4-8:1993 (1 A/m at frequency 50 Hz)
• Voltage dips, short interruptions and voltage variations immunity test
according to EN 61000-4-11:1994 (>95% Reduction @10 ms, 30%
Reduction @500 ms, >95% Reduction @5000 ms)
LVD: • EN 60950 (A1/1992; A2/1993; A3/1993; A4/1995; A11/1997)

vii
T ABLE OF C ONTENTS
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-1
Features and Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Networking Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
ADSL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
ATM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Route Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Bridging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Network Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Accessing a Remote Site . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Accessing the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
2 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Package Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Hardware Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
LED Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
System Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Connect the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Phone Line Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Installing a Full-rate Connection . . . . . . . . . . . . . . . . . . . . . 2-4
Installing a Splitterless Connection . . . . . . . . . . . . . . . . . . . 2-5
Connect the ADSL Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Connect the Power Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Connect to the Barricade’s Ethernet Port . . . . . . . . . . . . . . . . . . 2-6
Connect to the Barricade’s USB Port . . . . . . . . . . . . . . . . . . . . . 2-7
3 Web-Based Management . . . . . . . . . . . . . . . . . . . . . . 3-1
Web-Based Configuration and Monitoring . . . . . . . . . . . . . . . . . . . . . . . 3-1
Logging into the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Navigating the Web Browser Interface . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Making Configuration Changes . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Setup Wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Advanced Setup Menu Overview . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Status (Toolbar Button) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

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viii
Advanced Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
WAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Asynchronous Transfer Mode (ATM) . . . . . . . . . . . . . . . . . 3-9
Protocol Encapsulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Protocol Multiplexing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
LAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
Session Name Configuration . . . . . . . . . . . . . . . . . . . . . . . 3-17
Virtual Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
Bridge Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-19
DNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
WAN Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
PPP Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22
Route Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23
Learned MAC Addr. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24
ADSL Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
RIP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-26
Password Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
Misc Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-27
Other Miscellaneous Functions . . . . . . . . . . . . . . . . . . . . . . . . . 3-31
Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-32
ADSL .. . . . . .... . . . . .... . . . . .... . . . . .... . . . . ... . . . . .3-34
LAN ... . . . . .... . . . . .... . . . . .... . . . . .... . . . . ... . . . . .3-36
WAN Status. . . . .... . . . . .... . . . . .... . . . . .... . . . . . . . .3-37
PPP Status.. . . . . . . . . .... . . . . .... . . . . .... . . . . .... . . . .3-38
TCP Status .. . . . . . . . . .... . . . . .... . . . . .... . . . . .... . . . .3-39
4 Configuring Client TCP/IP . . . . . . . . . . . . . . . . . . . . . 4-1
Windows 95/98/Me . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Configure TCP/IP Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Disable HTTP Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Internet Explorer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Netscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Obtain IP Settings from Your ADSL Router . . . . . . . . . . . . . . . 4-5
Windows 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Configure TCP/IP Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Disable HTTP Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9

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Obtain IP Settings from Your Barricade . . . . . . . . . . . . . . . . . . . 4-9
Windows NT 4.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Configure TCP/IP Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Disable HTTP Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13
Obtain IP Settings from Your Barricade . . . . . . . . . . . . . . . . . . 4-13
Configuring Your Macintosh Computer . . . . . . . . . . . . . . . . . . . . . . . . 4-14
Configure TCP/IP Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14
Disable HTTP Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Internet Explorer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-16
Netscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17
Obtain IP Settings from Your Barricade . . . . . . . . . . . . . . . . . . 4-18
A Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Diagnosing LED Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1
B Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Ethernet Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Wiring Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
RJ-45 Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
Pin Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
Straight-Through Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
Crossover Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
ADSL Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4
Wiring Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4
C Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Interface Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
ADSL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1
Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2
Advanced Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-2
Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3
Physical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3
D Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1

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1-1
C HAPTER 1
I NTRODUCTION
Congratulations on your purchase of the Barricade 2-Port Broadband
Router with built-in ADSL Modem. We are proud to provide you with a
powerful yet simple communication device for connecting your PC to the
Internet.
The Barricade is an Asynchronous Digital Subscriber Line (ADSL)
network device that provides high-speed Internet access over existing
phone lines. It supports both full-rate Discrete Multi-Tone (G.dmt)
connection (up to 8 Mbps downstream and 640 Kbps upstream), as well as
the more economical splitterless G.lite connection (up to 1.5 Mbps
downstream and 512 Kbps upstream).
The Barricade delivers concurrent data and voice over a single connection
(using a splitter for G.dmt but not G.lite). It also supports a Rate Adaptive
algorithm to maintain data integrity under almost all existing conditions,
including various connection lengths and degraded signal quality. Because
all data crossing the ADSL link is encapsulated in ATM frames, the
Barricade can be connected directly to any standards-compliant DSL
Access Multiplexer (DSLAM) at your service provider’s central office.
Data can then be sent through an ATM backbone, and out to the Internet.
Moreover, there’s no need to install any new lines, nor is there is any need
for a truck roll to the customer’s premises when using splitterless G.lite
ADSL.
The Barricade provides an always-on digital connection that eliminates
dial-up delays, and supports transparent reconnection when initiating a
network request. Full support for Asynchronous Transfer Mode (ATM)
protocol also provides access to a wide range of advanced transport
features, including support for real-time video, and other multimedia

I NTRODUCTION
1-2
services requiring guaranteed Quality of Service (QoS). The Barricade
enables true telecommuting for the first time. It also provides
multiprotocol encapsulation for bridging Windows NetBEUI and Novell’s
IPX protocols directly to a remote site for complete access to corporate
resources, or for routing TCP/IP traffic for Internet connections.
Features and Benefits
• High-speed Internet access over existing phone lines
• Full-rate DMT connection (8 Mbps downstream, 640 Kbps upstream)
and splitterless G.lite connection (1.5 Mbps downstream, 512 Kbps
upstream)
• Multiprotocol encapsulation of Windows NetBEUI, Novell’s IPX and
TCP/IP via bridging for complete access to corporate resources
• TCP/IP routing transport using RIP-2 for Internet access
• Network Address Translation (NAT) and Network Address and Port
Translation (NAPT) enables multiple user Internet access with a single
user account, flexible local IP address administration, and firewall
protection
• Virtual Server allows remote users access to various services at your
site using a constant IP address
• Dynamic Host Configuration Protocol (DHCP) for dynamic IP
address assignment as a server or server relay
• DHCP Relay enables a host to obtain basic TCP/IP configuration
information from a DHCP server, even if the server does not reside on
the local subnet
• IGMP Proxy capability allows users anywhere on a downstream
network to join an upstream sourced multicast group

F EATURES AND B ENEFITS
1-3
• Supports pass-through for three of the most commonly used Virtual
Private Network (VPN) protocols – PPTP, L2TP, and IPSec
• Security protocols, including Password Authentication Protocol (PAP)
and Challenge Handshake Authentication Protocol (CHAP)
• Always-on digital connection eliminates dial-up delays, and transparent
reconnection when initiating a network request
• Concurrent data and voice over a single connection (needs splitter for
G.dmt but not G.lite)
• Interoperable with T1.413-standard DSLAMs, as well as other central
office equipment manufacturers such as Cisco and Alcatel T1.413-like
DSLAMs
• Compatible with various ISP services, using static or dynamic IP
assignment via the router’s built-in DHCP server
• Web interface for ADSL connection management

I NTRODUCTION
1-4
Networking Concepts
ADSL
Digital Subscriber Line (DSL) technology transmits both data and voice
over ordinary telephone lines. Signals above 4 kHz are cut off in normal
telephone communications as noise, so DSL uses this spectrum to
transmit data.
Since Internet users and people telecommuting from home normally
download more data than they upload, Asymmetric Digital Subscriber Line
(ADSL) is the preferred choice. Full-rate ADSL utilizes Discrete
Multi-Tone (DMT) signaling to transmit data at up to 8 Mbps downstream
and 640 Kbps upstream. While the more economical splitterless G.lite
connection transmits data at up to 1.5 Mbps downstream and 512 Kbps
upstream.
Because the ADSL signal path is always on, you no longer have to wait
each time you want to access the Internet or a remote site. Moreover, with
multiprotocol encapsulation that includes TCP/IP, NetWare IPX, and
Windows NetBEUI, you have instant access to the Internet, as well as all
the networked resources at your office, including file servers, printers, or
multimedia services. The ADSL Router makes telecommuting a real
possibility for the first time.
ATM
This router uses Asynchronous Transfer Mode (ATM) over ADSL since
ATM permits the concurrent transmission of data, voice, and video. ATM
is a transport mechanism that configures a network connection between
two nodes as a Virtual Path (VP) running across a series of routers or
Layer-3 switches. A Virtual Path can contain many different Virtual
Circuits (VC), each of which is set up to transport a unique data flow
between the source and destination node.

N ETWORKING C ONCEPTS
1-5
Data flows are broken up into fixed length cells, each of which contains a
Virtual Path Identifier (VPI) that identifies the path between two nodes,
and a Virtual Circuit Identifier (VCI) that identifies the data channel within
that virtual path. Each virtual circuit maintains a constant flow of cells
between the two end points. When there is no data to transmit, empty cells
are sent; when data needs to be transmitted, it is immediately inserted into
the cell flow.
Route Determination
Depending on the ATM transport protocol used, this router can handle
traffic as a Layer-2 bridge, using only the physical address stored in the
packet’s source and destination address fields. Or it can forward traffic as a
fully functional Layer-3 router, using a specific route (that is, next hop) for
each IP host or subnet that is statically configured or learned through
dynamic routing protocols.
Bridging
If ATM Protocol Encapsulation is set for Ethernet/ATM (RFC 1483), the
router behaves like a wire directly connecting your local network to the
ISP. The router acts as a transparent bridge between a local PC or LAN
attached to the Ethernet port and a remote site across the ADSL link.
Bridging can be used to make two separate networks appear as if they were
part of the same physical network. Bear in mind that compared to routing,
bridging generates a lot more traffic and can significantly slow down the
router.

I NTRODUCTION
1-6
Routing
If ATM Protocol Encapsulation is set for PPP/ATM or IP/ATM, the
router will forward incoming IP packets and use RIP-2 for routing path
management if enabled. The router supports both static routing and
dynamic routing.
• Static routing requires routing information to be stored in the router,
either manually or when a connection is set up, by an application
outside the router.
• Dynamic routing uses a routing protocol to exchange routing
information, calculate routing tables, and respond to changes in the
status or traffic on the network.
Dynamic Routing Protocols - The Barricade supports RIP-2 dynamic
routing protocol. Routing Information Protocol (RIP) is the most widely
used method for dynamically maintaining routing tables. RIP uses a
distance vector-based approach to routing. Routes are chosen to minimize
the distance vector, or hop count, which serves as a rough estimate of
transmission cost. Each router broadcasts its advertisement every 30
seconds, together with any updates to its routing table. This allows all
routers on the network to build consistent tables of next hop links which
lead to relevant subnets.
RIP-2 is a compatible upgrade to RIP. However, RIP-2 adds useful
capabilities for plain text authentication, multiple independent RIP
domains, variable length subnet masks, and multicast transmissions for
route advertising (see RFC 1723).
Note: If the destination route is not found in the routing table, the router simply
transmits the packet to a default router for resolution.