Spectrum 24 AP-4111 DS Installation and operation manual

www.symbol.com
Spectrum24
AP-4111DS Access Point
Product Reference Guide
70-20688-01
Revision A
November 1999

ii Spectrum24 Access Point AP-3020 Product Reference Guide
Copyright
Copyright © 1999 by Symbol Technologies, Inc. All rights reserved.
No part of this publication may be modified or adapted in any way, for any purposes without permission in writing from Symbol. The material in this manual
is subject to change without notice.
Symbol reserves the right to make changes to any product to improve reliability, function, or design.
No license is granted, either expressly or by implication, estoppel, or otherwise under any Symbol Technologies, Inc., intellectual property rights. An implied
license only exists for equipment, circuits, and subsystems contained in Symbol products.
Symbol, the Symbol logo and Spectrum24 are registered trademarks of Symbol Technologies, Inc.
Other product names mentioned in this manual may be trademarks or registered trademarks of their respective companies and are hereby acknowledged.
IBM is a registered trademark of International Business Machine Corporation.
Microsoft, Windows, and Windows NT are registered trademarks of Microsoft Corporation.
Novell and LAN Workplace are registered trademarks of Novell Inc.
Toshiba is a trademark of Toshiba Corporation.
Patents
This product is covered by one or more of the following U.S. and foreign Patents:
U.S. Patent No.
4,360,798; 4,369,361; 4,387,297; 4,460,120; 4,496,831; 4,593,186; 4,603,262; 4,607,156; 4,652,750; 4,673,805;
4,736,095; 4,758,717; 4,816,660; 4,845,350; 4,896,026; 4,897,532; 4,923,281; 4,933,538; 4,992,717; 5,015,833;
5,017,765; 5,021,641; 5,029,183; 5,047,617; 5,103,461; 5,113,445; 5,130,520; 5,140,144; 5,142,550; 5,149,950;
5,157,687; 5,168,148; 5,168,149; 5,180,904; 5,216,232; 5,229,591; 5,230,088; 5,235,167; 5,243,655; 5,247,162;
5,250,791; 5,250,792; 5,260,553; 5,262,627; 5,262,628; 5,266,787; 5,278,398; 5,280,162; 5,280,163; 5,280,164;
5,280,498; 5,304,786; 5,304,788; 5,306,900; 5,321,246; 5,324,924; 5,337,361; 5,367,151; 5,373,148; 5,378,882;
5,396,053; 5,396,055; 5,399,846; 5,408,081; 5,410,139; 5,410,140; 5,412,198; 5,418,812; 5,420,411; 5,436,440;
5,444,231; 5,449,891; 5,449,893; 5,468,949; 5,471,042; 5,478,998; 5,479,000; 5,479,002; 5,479,441; 5,504,322;
5,519,577; 5,528,621; 5,532,469; 5,543,610; 5,545,889; 5,552,592; 5,557,093; 5,578,810; 5,581,070; 5,589,679;
5,589,680; 5,608,202; 5,612,531; 5,619,028; 5,627,359; 5,637,852; 5,664,229; 5,668,803; 5,675,139; 5,693,929;
5,698,835; 5,705,800; 5,714,746; 5,723,851; 5,734,152; 5,734,153; 5,742,043; 5,745,794; 5,754,587; 5,762,516;
5,763,863; 5,767,500; 5,789,728; 5,789,731; 5,808,287; 5,811,785; 5,811,787; 5,815,811; 5,821,519; 5,821,520;
5,823,812; 5,828,050; 5,850,078; 5,861,615; 5,874,720; 5,875,415; 5,900,617; 5,902,989; 5,907,146; 5,912,450;
5,914,478; 5,917,173; 5,920,059; 5,923,025; 5,929,420; 5,945,658; 5,945,659; 5,946,194; 5,959,285; D305,885;
D341,584; D344,501; D359,483; D362,453; D363,700; D363,918; D370,478; D383,124; D391,250; D405,077;
D406,581; D414,171; D414,172
Invention No. 55,358; 62,539; 69,060; 69,187 (Taiwan); No. 1,601,796; 1,907,875; 1,955,269 (Japan); European Patent 367,299; 414,281;
367,300; 367,298; UK 2,072,832; France 81/03938; Italy 1,138,713
Symbol Technologies, Inc.
One Symbol Plaza
Holtsville, N.Y. 11742-1300
Telephone:(800)SCAN234, [phone], TLX:6711519
www.symbol.com

Spectrum24 Access Point AP-3020 Product Reference Guide iii
About This Document
Reference Documents
This reference guide refers to the following documents:
Conventions
Keystrokes are indicated as follows:
Typeface conventions used include.
Part Number Document Title
70-20706-01 Wireless LAN Adapter Models LA-4111 PC Card & LA-4113 PCI Adapter
Product Reference Guide
70-20709-01 Spectrum24 Plus Pack Users Guide
70-20708-01 Spectrum24 Site Survey System Administrators Guide
ENTER identifies a key.
FUNC, CTRL, C identifies a key sequence. Press and release each key in turn.
Press A+B press the indicated keys simultaneously.
Hold A+B press and hold the indicated keys while performing or waiting for another
function. Used in combination with another keystroke.
<angles> indicates mandatory parameters in syntax.
[brackets] for command line, indicates available parameters; in configuration files,
brackets act as separators for options.
GUI Screen text indicates the name of a control in a GUI-based application.
Italics indicates the first use of a term, book title, variable or menu title.
Screen indicates monitor screen dialog. Also indicates user input. A screen is
the hardware device on which data appears. A display is data arranged
on a screen.
Terminal indicates text shown on a radio terminal screen.
URL indicates Uniform Resource Locator.

iv Spectrum24 Access Point AP-3020 Product Reference Guide
This document uses the following for certain conditions or information:
Indicates tips or special requirements.
Indicates conditions that can cause equipment damage or data loss.
Indicates a potentially dangerous condition or procedure that only Symbol-
trained personnel should attempt to correct or perform.

Contents
Spectrum24 AP-4111 DS Access Point Product Reference Guide v
Chapter 1 Introduction...................................................................................1
1.1 Access Point (AP)...........................................................................2
1.2 Radio Basics .................................................................................4
1.2.1 S24 Network Topology........................................................4
1.2.2 Cellular Coverage ..............................................................7
1.2.3 Site Topography .................................................................8
1.3 Advanced Radio Theory.................................................................9
1.3.1 MAC Layer Bridging............................................................9
1.3.2 DHCP Support..................................................................11
1.3.3 Media Types.....................................................................12
1.3.4 Bridging Support ..............................................................13
1.3.5 Direct-Sequence Spread Spectrum......................................17
1.3.6 MU Association Process .....................................................19
1.3.7 Mobile IP .........................................................................20
1.3.8 Supporting CAM and PSP Stations ......................................23
1.3.9 Data Encryption................................................................24
1.3.10 HTTP, HTML Web Server Support .....................................25
1.3.11 Management Options .....................................................26
Chapter 2 Configuring the AP ....................................................................29
2.1 Gaining Access to the UI .............................................................29
2.1.1 Using Telnet .....................................................................29
2.1.2 Using a Direct Serial Connection........................................31
2.1.3 Using a Dial-Up Connection..............................................32
2.1.4 Using a Web Browser........................................................33
2.2 Navigating the UI .......................................................................39
2.2.1 Entering Admin Mode .......................................................41
2.2.2 Changing the Access to the UI ...........................................42
2.2.3 Configuring for Dial-Up to the UI.......................................43

vi Spectrum24 AP-4111 DS Access Point Product Reference Guide
2.2.4 Navigating the UI Via a Web Browser .................................44
2.3 Access Point Installation...............................................................45
2.4 Configuring System Parameters....................................................47
2.5 Configuring Radio Parameters .....................................................50
2.6 Configuring PPP..........................................................................54
2.6.1 PPP Direct ........................................................................54
2.6.2 Establishing Connection ....................................................55
2.6.3 PPP with Modems..............................................................55
2.6.4 Originating AP .................................................................55
2.6.5 Answering AP ...................................................................56
2.6.6 Initiating Modem Connection.............................................57
2.7 Configuring the SNMP Agent .......................................................57
2.8 Configuring the ACL ...................................................................61
2.8.1 Range of MUs ..................................................................61
2.8.2 Adding Allowed MUs ........................................................63
2.8.3 Removing Allowed MUs.....................................................63
2.8.4 Enable/Disable the ACL ....................................................64
2.8.5 Removing All Allowed MUs ................................................64
2.8.6 Load ACL from MU List .....................................................64
2.9 Configuring Address Filtering.......................................................65
2.9.1 Adding Disallowed MUs ....................................................66
2.9.2 Removing Disallowed MUs ................................................66
2.10 Configuring Type Filtering .........................................................66
2.10.1 Adding Filter Types .........................................................66
2.10.2 Removing Filter Types......................................................66
2.10.3 Controlling Type Filters....................................................67
2.11 Clearing MUs from the AP .........................................................67
2.12 Setting Logging Options ............................................................68
2.13 Manually Updating AP Firmware ................................................70
2.13.1 Update using TFTP..........................................................70
2.13.2 Updating using Xmodem .................................................72

Spectrum24 AP-4111 DS Access Point Product Reference Guide vii
2.14 Auto Upgrade all APs Via Messaging..........................................75
2.15 Performing Pings ......................................................................77
2.16 Mobile IP Using MD5 Authentication...........................................80
2.17 Saving the Configuration ...........................................................80
2.18 Resetting the AP ........................................................................82
2.19 Restoring the Factory Configuration ............................................82
Chapter 3 Monitoring Statistics ..................................................................83
3.1 System Summary ........................................................................83
3.2 Interface Statistics........................................................................85
3.3 Forwarding Counts .....................................................................86
3.4 Mobile Units...............................................................................87
3.5 Mobile IP....................................................................................91
3.6 Known APs .................................................................................92
3.7 Ethernet Statistics ........................................................................93
3.8 Radio Statistics............................................................................95
3.9 Miscellaneous Statistics................................................................98
3.9.1 Analyzing Frequency Use.................................................100
3.9.2 Analyzing Retries ............................................................101
3.10 Event History ..........................................................................102
3.11 Clearing Statistics....................................................................103
Chapter 4 Hardware Installation..............................................................105
4.1 Precautions ..............................................................................105
4.2 Package Contents .....................................................................105
4.3 Requirements ...........................................................................106
4.3.1 Network Connection .......................................................106
4.3.2 10Base-T UTP ................................................................106
4.3.3 Single Cell .....................................................................107
4.4 Placing the AP ..........................................................................107
4.5 Power Options..........................................................................107
4.6 Mounting the AP .......................................................................108
4.7 Connecting the Power Adapter...................................................108

viii Spectrum24 AP-4111 DS Access Point Product Reference Guide
4.8 LED Indicators ..........................................................................109
4.9 Troubleshooting........................................................................110
4.9.1 Ensure wired network is operating ....................................110
4.10 Setting Up MUs.......................................................................111
Appendix A Specifications ............................................................................ A-1
A.1 Physical Characteristics ............................................................. A-1
A.2 Radio Characteristics................................................................. A-2
A.3 Network Characteristics............................................................ A-3
Appendix B Supported Modems ................................................................. B-1
Appendix C Customer Support....................................................................C-1
Appendix D Regulatory Addendum ............................................................D-1
Index............................................................................................................. Index-1

Spectrum24 AP-4111 DS Access Point Product Reference Guide 1
Chapter 1 Introduction
Spectrum24 is a spread spectrum cellular network that operates between
2.4 and 2.5 GHz (gigahertz). This technology provides a high-capacity
network using multiple access points within any environment.
The Symbol AP-4111 access point (AP) is a Spectrum24 direct-sequence (DS)
product. Spectrum24 DS products use direct-sequence technology to provide
a high-capacity, high-data-rate wireless network.
Spectrum24 DS infrastructure products include:
• bridging architecture to provide communication between radio and
wired multiple network segments
• a design based on the IEEE 802.11 standard
• an 11 Mbps data rate for fast operation
• seamless roaming for mobile users with devices such as laptops, wireless
PCs, scanning terminals and other computers with PCMCIA slots.

Introduction
2 Spectrum24 AP-4111 DS Access Point Product Reference Guide
1.1 Access Point (AP)
The Access Point (AP) provides a bridge between Ethernet wired LANs and
Spectrum24 wireless networks. It provides connectivity between Ethernet
wired networks and radio-equipped mobile units (MUs). MUs include the full
line of Symbol Spectrum24 terminals, PC Cards and PCI adapters, bar-code
scanners, third-party devices and other devices.
The AP provides an 11 Mbps data transfer rate on the radio network.
It monitors Ethernet traffic and forwards appropriate Ethernet messages to
MUs over the Spectrum24 network. It also monitors MU radio traffic and
forwards MU packets to the Ethernet LAN.
The AP meets the following:
•the regulatory requirements for Europe and many other areas of
the world
•FCC part 15, class A with no external shielding
•FCC part 15 class B, ETS 300-339 compliance, including CE mark.

Introduction
Spectrum24 AP-4111 DS Access Point Product Reference Guide 3
The AP has the following features:
•built-in diagnostics including a power-up self-check
•built-in dual antenna assembly with optional diversity
•wireless MAC interface
•field upgradable Firmware
•10baseT Ethernet port interface with full-speed filtering
•power supply IEC connector and a country-specific AC power cable
•PC/AT Serial Port Interface
•support for up to 127 MUs
•data encryption
•increased MIB support
•SNMP support
•Mobile IP support
•DHCP support
•HTTP Web server support.
When properly configured, an MU communicating with an AP appears on
the network as a peer to other network devices. The AP receives data from its
wired interfaces and forwards the data to the proper interface.
The AP has connections for the wired network and power supply. The AP
attaches to a wall or ceiling depending on installation-site requirements.

Introduction
4 Spectrum24 AP-4111 DS Access Point Product Reference Guide
1.2 Radio Basics
Spectrum24 devices use both electromagnetic waves to transmit and receive
electric signals without wires. Users communicate with the network by
establishing radio links between terminals and APs.
Spectrum24 uses FM (frequency modulation) to transmit digital data from
one device to another. Using FM, a radio signal begins with a carrier signal
that provides the base or center frequency. The digital data signal is
superimposed on the carrier signal (modulation). The radio signal
propagates into the air as electromagnetic waves. A receiving antenna in the
path of the waves absorbs the waves as electrical signals. The receiving
device demodulates the signal by removing the carrier signal. This
demodulation results in the original digital data.
Spectrum24 uses the environment (the air and certain objects) as the
transmission medium. Spectrum24 radio devices transmit in the 2.4 to
2.5-GHz frequency range, a license-free range throughout most of the
world. The actual range is country-dependent.
Spectrum24 devices, like other Ethernet devices, have unique, hardware-
encoded Media Access Control (MAC) or IEEE addresses. MAC addresses
determine the device sending or receiving data. A MAC address is a 48-bit
number written as six hexadecimal bytes separated by colons. For example:
00:A0:F8:24:9A:C8
To locate the AP MAC address see the bottom of the unit.
1.2.1 S24 Network Topology
The variations possible in Spectrum24 network topologies depend on the
following factors:
•the AP function in the network
•the data transfer rate

Introduction
Spectrum24 AP-4111 DS Access Point Product Reference Guide 5
Select from the following topologies:
•A single AP used without the wired network provides a single-cell wireless
network for peer-to-peer MUs.
•A single AP can bridge the Ethernet and radio networks.

Introduction
6 Spectrum24 AP-4111 DS Access Point Product Reference Guide
•Multiple APs can coexist as separate, individual networks at the same site
without interference using different Net_IDs.
•Multiple APs wired together provide a network with better coverage area
and performance when using the same Net_IDs.

Introduction
Spectrum24 AP-4111 DS Access Point Product Reference Guide 7
1.2.2 Cellular Coverage
The AP establishes an average communication range with MUs called a
Basic Service Set (BSS) or cell. When in a particular cell the MU associates
and communicates with the AP of that cell. Each cell has a Basic Service Set
Identifier (BSS_ID). In IEEE 802.11, the AP MAC address represents the
BSS_ID. The MU recognizes the AP it associates with using the BSS_ID.
Adding APs to a LAN establishes more cells in an environment, making it an
RF Network using the same Net_ID or Extended Service Set (ESS).
APs with the same Net_ID (ESS) define a coverage area. The MU searches
for APs with a matching Net_ID (ESS) and synchronizes with an AP to
establish communications. This allows MUs within the coverage area to move
about or roam. As the MU roams from cell to cell, it switches APs. The switch
occurs when the MU analyzes the reception quality at a location and decides
the AP to communicate with based on the best signal strength and lowest MU
load distribution.
If the MU does not find an AP with a workable signal, it performs a scan to
find any AP. As MUs switch APs, the AP updates the association table.
BSS_ID
NET_ID

Introduction
8 Spectrum24 AP-4111 DS Access Point Product Reference Guide
The user can configure the Net_ID (ESS). A valid Net_ID (ESS) is an
alphanumeric, case-sensitive identifier up to 32 characters. Ensure all nodes
within one LAN use the same Net_ID (ESS) to communicate on the same
LAN. Multiple wireless LANs can coexist in a single environment by assigning
different Net_IDs (ESS) for APs.
1.2.3 Site Topography
For optimal performance, locate MUs and APs away from transformers,
heavy-duty motors, fluorescent lights, microwave ovens, refrigerators and
other industrial equipment.
Signal loss can occur when metal, concrete, walls or floors block
transmission. Locate APs in open areas or add APs as needed to
improve coverage.
Site Surveys
A site survey analyzes the installation environment and provides users with
recommendations for equipment and its placement. The optimum placement
of 11 Mbps access points differs for 1 or 2 Mbps access points, because the
locations and number of access points required are different.
Symbol recommends conducting a new site survey and developing a new
coverage area floor plan when switching from 1 or 2 Mbps frequency-
hopping access points to 11 Mbps direct-sequence access points.

Introduction
Spectrum24 AP-4111 DS Access Point Product Reference Guide 9
1.3 Advanced Radio Theory
To improve AP management and performance, users need to understand
basic AP functionality and configuration options. The AP includes features for
different interface connections and network management.
The AP provides MAC layer bridging between its interfaces. The AP monitors
traffic from its interfaces and, based on frame address, forwards the frames
to the proper destination. The AP tracks the frames sources and destinations
to provide intelligent bridging as MUs roam or network topologies change.
The AP also handles broadcast and multicast message initiations and
responds to MU association requests.
1.3.1 MAC Layer Bridging
The AP listens to all packets on all interfaces and builds an address database
using the unique IEEE 48-bit address (MAC address). An address in the
database includes the interface media that the device uses to associates with
the AP. The AP uses the database to forward packets from one interface to
another. The bridge forwards packets addressed to unknown systems to the
Default Interface (either Ethernet or PPP).

Introduction
10 Spectrum24 AP-4111 DS Access Point Product Reference Guide
The AP internal stack interface handles all messages directed to the AP.
Each AP stores information on destinations and their interfaces to facilitate
forwarding. When a user sends an ARP (Address Resolution Protocol) request
packet, the AP forwards it over all enabled interfaces (Ethernet, PPP and
radio) except over the interface the ARP request packet was received.
On receiving the ARP response packet, the AP database keeps a record
of the destination address along with the receiving interface. With this
information, the AP forwards any directed packet to the correct destination.
The AP forwards packets for unknown destinations to the Ethernet interface.
Transmitted ARP request packets echo back to other MUs.
The AP removes from its database destinations or interfaces not used for a
specified time. The AP refreshes its database when it transmits or receives
data from these destinations and interfaces.
Filtering and Access Control
The AP provides facilities to limit the MUs that associate with it and the data
packets that can forward through it. Filters provide network security or
improve performance by eliminating broadcast/multicast packets from the
radio network.
The ACL (Access Control List) contains MAC addresses for MUs
allowed to associate with the AP. This provides security by preventing
unauthorized access.
The AP uses a disallowed address list of destinations. This feature prevents
the AP from communicating with specified destinations. This can include
network devices that do not require communication with the AP or its MUs.

Introduction
Spectrum24 AP-4111 DS Access Point Product Reference Guide 11
Depending on the setting, the AP can keep a list of frame types that it
forwards or discards. The Type Filtering option prevents specific frames
(indicated by the 16-bit DIX Ethernet Type field) from being processed by the
AP. These include certain broadcast frames from devices unimportant to the
wireless LAN but take up bandwidth. Filtering out unnecessary frames can
also improve performance.
1.3.2 DHCP Support
The AP uses Dynamic Host Configuration Protocol (DHCP) to obtain a leased
IP address and network configuration information from a remote server.
DHCP is based on BOOTP protocol. DHCP can coexist or interoperate with
BOOTP. An AP sends out a DHCP request searching for a DHCP server to
acquire the network configuration and firmware filenames. Because BOOTP
and DHCP interoperate, the one that responds first becomes the server that
allocates information. The DHCP client automatically sends a DHCP request
every XX hours/days to renew the IP address lease as long as the AP is
running. (This parameter is programmed at the DHCP server. Example:
Windows NT servers typically are set for 3 days.)
The AP can optionally download two files when a boot takes place, the
firmware file and an HTML file. Users can program the DHCP or BOOTP
server to transfer these two files when a DHCP request is made.
When the AP receives a network configuration change or is not able to renew
the IP address lease the AP sends out an SNMP trap.
Mobile IP is not available when DHCP is used. Disable DHCP support when
configuring an AP and mobile device for Mobile IP.

Introduction
12 Spectrum24 AP-4111 DS Access Point Product Reference Guide
1.3.3 Media Types
The AP supports bridging between Ethernet, radio and serial media.
The Ethernet interface fully complies with Ethernet Rev. 2 and IEEE 802.3
specifications. The AP supports 10Base-T wired connections and full-speed
filtering. The data transfer rate over radio waves is 11 Mbps. The Ethernet
interface is optional for single-cell or PPP-connected networks.
The radio interface conforms to IEEE 802.11 specifications. The interface
operates at 11 Mbps using direct-sequence radio technology. The AP
supports multiple-cell operations with fast roaming between cells. With the
direct-sequence system, each cell operates independently. Each cell provides
an 11 Mbps bandwidth. Adding cells to the network provides increased
coverage area and total system capacity. The AP supports MUs operating in
Power Save Polling (PSP) mode or Continuously Aware Mode (CAM) without
user intervention.
The DB-9, 9-pin, RS-232 serial port provides a UI (User Interface) or a PPP
(Point to Point Protocol) connection. The UI provides basic management tools
for the AP. The PPP provides a link between APs using a serial connection.
The serial link supports short haul (direct serial) or long haul (telephone-line)
connections. The AP is a DTE (Data Terminal Equipment) device with male
pin connectors for the RS-232 port. Connecting the AP to a PC requires a
null modem cable and connecting the AP to a modem requires a straight-
through cable.