ALFA Network AP51 User Manual

User Guide

AP51

IEEE 802.11b/g High-Power Wireless AP/Router

Table of Contents

Chapter 1: Introduction 1-1

Package Checklist 1-1
Hardware Description 1-2

LED Indicators 1-3
Ethernet RJ-45 Ports 1-3
Power Socket 1-4
Reset Button 1-4
WPS SET Button 1-4

Chapter 2: Installation 2-1

WISP Mode 2-1
Home Bridge Mode 2-2
Home Router Mode 2-2

Chapter 3: Network Planning 3-1

Internet Gateway Router 3-1
LAN Acce ss Point 3-2
Wireless Client 3-2
Wireless Bridge 3-3

Appendix A: Troubleshooting A-1

Appendix B: Specifications B-1

Glossary

Chapter 1: Introduction

The AP51 is an IEEE 802.11b/g wireless High-Power
Internet access device (cable or ADSL modem) to your PC or local area network, or to
its own secure wireless network.

AP/

Route that connects your

Package Checklist

The AP51 AP/Router package includes:

1.

2.

3.
Inform your dealer if there are any incorrect, missing or damaged parts. If possible,

retain the carton, including the original packing materials. Use them again to repack
the product in case there is a need to return it.

AP51
AC power adapter
User Manual CD

1-1

1

Introduction

Hardware Description

Wall Mount Slots

LED

Power Socket

Ethernet RJ-45 Port

Detachable
Antenna

Reset But t on

1-2

LED Indicators

The AP51 includes three status LED indicators, as described in the following figure and
table.

Wireless Link/Activity

Ethernet Link

Power

LED Status Description

Power On Indicates AP51 is power on
Ethernet

WLAN

Hardware Description

1

On Indicates a valid link on Ethernet

Port

Off The Ethernet port has no valid

link

On/Flashing Indicates the 802.11b/g radio is

enabled. Flashing indicates
wireless network activity

Off Indicates the 802.11b/g radio is

disabled

Ethernet RJ-45 Ports

The AP51 has the following RJ-45 ports:

z
z

The Ethernet RJ-45 port auto-negotiate the operating speed to 10/100 Mbps, the
mode to half/full duplex, and the pin signals to MDI/MDI-X. Automatic MDI/MDI-X
support enables you to use straight-through cables for all network connections to PCs,
switches, or hubs.

As Ethernet RJ-45 LAN port is for connection to a PC or to a 10/100 Mbps.
As Ethernet RJ-45 WAN port is for connection to a DSL or cable modem, or to a

LAN or other device that provides your Internet access.

1-3

1

Introduction

Power Socket

The AP51 does not have a power switch. It is powered on when connected to the AC
power adapter, and the power adapter is connected to a power source.
The power adapter automatically adjusts to any voltage between 100-240 volts at 50
or 60 Hz. No voltage range settings are required.

Reset Button

The Reset button can be used to restart the AP51 or restore the factory default
configuration. If you press the button for less than 5 seconds, the AP51 will restart. If
you press and hold down the button for 5 seconds or more, any configuration changes
you may have made are removed and the AP51 is restored to its factory default
configuration.

1-4

Chapter 2: Installation

The AP51 has four basic operating modes that can be set through the web
management interface:







WISP Mode –

interface as Client to access the WISP Station

Home Bridge Mode –

one SSID as Reapter

Home Router Mode – work as AP+Router, Ethernet port become WAN

port to connect to cable or ADSL modem

WISP Mode

WISP Base Station

IP:192.168.1.2
SSID: WISP

work as AP+Client, one interface as AP and the other

work as AP+WDS Reapter, one SSID as AP and

WLAN 1 connect to
SSID: WISP

WLAN 2
IP: 10.0.0.2
SSID: Home

IP:10.0.0.25

IP: 10.0.0.23

2-1

2

ge Mode

Installation

Home Bridge Mode

Home Router Mode

IP: 10.0.0.23

IP: 10.0.0.26

IP: 10.0.0.2
SSID: Home

Cable or ADSL modem

Internet

Chapter 3: Network Planning

The AP51 is designed to be very flexible in its deployment options. It can be used as

Internet gateway for a small network, or as an access point to extend an

an
existing wired network to support wireless users. It also supports use as a
wireless client to connect to another wireless network, or a wireless bridge to
connect two wired LANs.

This chapter explains some of the basic features of the AP51 and shows some
network topology examples in which the device is implement ed.

Internet Gateway Router

The AP51 can connect directly to a cable or DSL modem to provide an Internet
connection for multiple users through a single service provider account. Users
connect to the AP51 either through a wired connection to the LAN port, or though the
deviceís own wireless network. The AP51 functions as an Internet gateway when set
to Router Mode.

An Internet gateway employs serveral functions that essentially creates two
separate Internet Protocol (IP) subnetworks; a private internal network with wired
and wireless users and a public external network that connects to the Internet.
Network traffic is forwarded, or routed, between the two subnetworks.

Internet
Service
Provider

Cable/DSL

The private local network, connected to the LAN port or wireless interface, provides
a Dynamic Host Configurati on Protocol (DHCP) server for allocating IP addresses to
local PCs and wireless clients, and Network Address Translation (NAT) for mapping
the multiple "internal" IP addresses to one "external" IP address.

Modem

LAN Switch

AP51

Desktop PC

(IP: 192.168.1.x)

Notebook PC

(IP: 192.168.1.x)

Server

(IP: 192.168.1.x)

3-1

3

Network Planning

The public external network, connected to the WAN port, supports DHCP client and
Point-to-Point Protocol over Ethernet (PPPoE) for connection to an Internet service
provider (ISP) through a cable or DSL modem:

LAN Access Point

The AP51 can provide an access point service for an existing wired LAN, creating a
wireless extension to the local network. The AP51 functions as purely an access
point when set to Bridge Mode. When used in this mode, there are no gateway
functions between the WAN port and the LAN and wireless interface.

A Wi-Fi wireless network is defined by its Service Set Identifier (SSID) or network

name. Wireless clients that want to connect to a network must set their SSID to the

same SSID of the network service. The AP51 supports two separate wireless
interfaces, that is two SSIDs or Virtual Access Points (VAPs). The two VAP interfaces
can be configured separately to support different security settings or other wireless
functions.

Server
(IP: 192.168.1.x)

Desktop PC

(IP: 192.168.1.x)

LAN Switch

Notebook PC

(IP: 192.168.1.x)

AP51

SSID 1

(public)

Notebook PC

(IP: 192.168.1.x)

SSID 2

(private)

Wireless Client

The AP51 can operate as a wireless client on one VAP interface, which enables a
connection to another wireless network.

The wireless client option requires the unit to be set to Router Mode. When the
wireless client option is enabled, the client VAP interface functions as the external
gateway interface instead of the WAN port. The other VAP interface, LAN port, and
WAN port all function as the local network within the same IP subnet.

3-2

Wireless Bridge

Wireless Bridge

The IEEE 802.11 standard defines a WIreless Distribution System (WDS) for bridge
connections between access points. The AP51 can use WDS to forward traffic on
links between units.

3

A single WDS bridge link can be specified for each VAP interface. One end of a link
must be configured as the ì
interface can be configured as a WDS Parent when the AP51 is set to either Router
Mode or Bridge Mode, but to be configured to WDS child the unit must be set to Bridge
Mode.

WDS Parentî

and the other as the ì

WDS Child.î A

VAP

Internet
Service
Provider

Cable/DSL

Modem

WDS Parent

AP51

(Router Mode)

AP51

(Bridge Mode)

WDS Child

LAN Switch

Server

(IP: 192.168.1.x)

Desktop PC

(IP: 192.168.1.x)

Desktop PC

(IP: 192.168.1.x)

3-3

Chapter 4: Initial Configuration

The AP51 offers a user-friendly web-based management interface for the
configuration of all the unit’s features. Any PC directly attached to the unit can access
the management interface using a web browser, such as Internet Explorer
(version 6.0 or above).

The initial configuration steps can be made through the web browser interface using
the Setup Wizard. It is recommended to make the initial changes by connecting a
PC directly to the AP51 before installing it in its intended location. The AP51 has a

default IP address of 10.0.0.1 and a subnet mask of

"Obtain an IP address automatically" (that is, set

immediately to the web interface. Otherwise, you must set your PC IP address to be
on the same subnet as the AP51 (that is, the PC and AP51 addresses must both start

10.0.0.x).

255.0.0.0. If your PC is set to

as a DHCP client), you can connect

4-1

4

Logging into the Web Interface

In the web browser’s address bar, type the default IP address: http://10.0.0.1. The
web browser displays the home page.

The default Username is “admin” with a default Password of “admin” Click OK to
access the web management interface.

Note: It is strongly recommen ded that you change the default user name and password.

If the default values are not changed, the management interface is not protected
and anyone that can connect to the access point may be able to compromise your
network security.

** All general function description is on the right of setup each page, will

no descript in this user Guide. **

4-2

Appendix A: Troubleshooting

Check the following items before you contact local Technical Support.

1. If wireless clients cannot access the network, check the following:
I.

II.

2. If the AP51 cannot be configured using a web browser:
I.

II.

Be sure the access point and the wireless clients are configured with the
same Service Set ID (SSID).

If authentication or encryption are enabled, ensure that the wireless clients
are properly configured with the appropriate authentication or encryption
keys.

Be sure to have configured the access point with a valid IP address,
subnet mask and default gateway.

If you are connecting to the AP51 through the wired Ethernet interface,
check the network cabling between the management station and the
AP51. If you are connecting to AP51 from a wireless client, ensure that
you have a valid connection to the AP51.

3. If you forgot or lost the password:
I.

4. If all other recovery measure fail, and the AP51 is still not functioning
properly, take any of these steps:

I

II

Set the AP51 to its default configuration by pressing the reset button on the
bottom panel for 5 seconds or more. Connect to the web management
interface using the default IP address 192.168.1.1. Then set up a new
user name and passward to access the management interface.

Reset the AP51 hardware using the web interface or through a power
reset.

Reset the AP51 to its default configuration by pressing the reset button on
the back panel for 5 seconds or more. Connect to the web management
interface using the default IP address 192.168.1.1, then setup a user
name and password.

Appendix B: Specifications

Wireless Receive Sensitivity

802.11b: -90 dBm @ 1 Mbps, -84 dBm @ 11 Mbps

802.11g: -86 dBm @ 6 Mbps, -68 dBm @ 54 Mbps

Operating Frequency

802.11g:

2.4 ~ 2.4835 GHz (US, Canada)

2.4 ~ 2.4835 GHz (ETSI, Japan)

802.11b:

2.4 ~ 2.4835 GHz (US, Canada)

2.4 ~ 2.4835 GHz (ETSI)

2.4 ~ 2.497 GHz (Japan)

Data Rate

802.11g: 6, 9, 12, 18, 24, 36, 48, 54 Mbps per channel

802.11b: 1, 2, 5.5, 11 Mbps per channel

Operating Channels

802.11g:

11 channels in base mode (US, Canada)
13 channels (ETSI, Japan)

802.11b:

11 channels in base mode (US, Canada)
13 channels (ETSI)
14 channels (Japan)

Modulation Type

802.11g: CCK, BPSK, QPSK, OFDM

802.11b: CCK, BPSK, QPSK

AC Power Adapter

Input: 100-240 VAC, 50-60 Hz
Output: 12 VDC, 1 A

LED Indicators

POWER, LAN (Ethernet Link/Activity), WLAN (Wireless Link/ Activity)

B-1

B

Specifications

Network Management

Web-browser

Temperature

Operating: 0 to 40 °C (32 to 104 °F)
Storage: -20 to 70 °C (32 to 158 °F)

Humidity

15% to 95% (non-condensing)

Compliances

FCC Part 15B Class B
EN 55022B
EN 55024
EN61000-3-2
EN61000-3-3
VCCI Class B

Radio Signal Certification

FCC Part 15C 15.247, 15.207 (2.4 GHz)
EN 300 328
EN 301 489-1
EN 301 489-17
ARIB STD-T66
IC RSS-210

Standards

IEEE 802.1 x
IEEE 802.11b, g
IEEE 802.3
Wi-Fi 11b/g, WPA, WPA2, WMM

Physical Size

12.5 x 7 x 2.7 cm (4.92 x 2.76 x 1.06 in)

Weight

170 g (6 oz)

B-2

Glossary

10BASE-T

IEEE 802.3 specification for 10 Mbps Ethernet over two pairs of Category 3 or better
UTP cable.

100BASE-TX

IEEE 802.3u specification for 100 Mbps Fast Ethernet over two pairs of Category 5
or better UTP cable.

Access Point

An internetworking device that seamlessly connects wired and wireless networks.
Access points attached to a wired network, support the creation of multiple radio
cells that enable roaming throughout a facility.

Advanced Encryption Standard (AES)

An encryption algorithm that implements symmetric key cryptography. AES provides
very strong encryption using a completely different ciphering algorithm to TKIP and
WEP.

Authentication

The process to verify the identity of a client requesting network access. IEEE 802.11
specifies two forms of authentication: open system and shared key.

Backbone

The core infrastructure of a network. The portion of the network that transports
information from one central location to another central location where it is unloaded
onto a local system.

Beacon

A signal periodically transmitted from the access point that is used to identify the
service set, and to maintain contact with wireless clients.

Broadcast Key

Broadcast keys are sent to stations using dynamic keying. Dynamic broadcast key
rotation is often used to allow the access point to generate a random group key and
periodically update all key-management capable wireless clients.

Dynamic Host Configuration Protocol (DHCP)

Provides a framework for passing configuration information to hosts on a TCP/IP
network. DHCP is based on the Bootstrap Protocol (BOOTP), adding the capability of
automatic allocation of reusable network addresses and additional configuration
options.

Glossary-1

Glossary

Encryption

Data passing between the access point and clients can use encryption to protect
from interception and evesdropping.

Ethernet

A popular local area data communications network, which accepts transmission
from computers and terminals.

File Transfer Protocol (FTP)

A TCP/IP protocol used for file transfer.

Hypertext Transfer Protocol (HTTP)

HTTP is a standard used to transmit and receive all data over the World Wide Web.

IEEE 802.11b

A wireless standard that supports wireless communications in the 2.4 GHz band
using Direct Sequence Spread Sp ectrum (DSSS). The standard provides for data
rates of 1, 2, 5.5, and 11 Mbps.

IEEE 802.11g

A wireless standa rd that supports wireless communications in the 2.4 GHz band using
using Orthogonal Frequency Division Multiplexing (OFDM). The standard provides for
data rates of 6, 9, 11, 12, 18, 24, 36, 48, 54 Mbps. IEEE 802.11g is also backward
compatible with IEEE 802.11b.

Infrastructure

An integrated wireless and wired LAN is called an infrastructure configuration.

Local Area Network (LAN)

A group of interconnected computer and support devices.

MAC Address

The physical layer address used to uniquely identify network nodes.

Network Time Protocol (NTP)

NTP provides the mechanisms to synchronize time across the network. The time
servers operate in a hierarchical-master-slave configuration in order to synchronize
local clocks within the subnet and to national time standards via wire or radio.

Open System

A security option which broadcasts a beacon signal including the access pointís
configur ed SSID. Wireless clients can read the SSID from the beacon, and
automatically reset their SSID to allow immediate connection to the nearest access
point.

Glossary-2

Orthogonal Frequency Division Multiplexing (ODFM)

Glossary

OFDM allows multiple users to transmit in an allocated band by dividing the
bandwidth into many narrow bandwidth carriers.

Repeater and Bridge

Repeater and bridge can provide an extended link to a remote access point from the
wired LAN. Access Point working in this mode could connect to another AP in
Access Point mode or Repeater and Bridge mode. Whenever there are two APs
having wireless link together (one in Access Point or Repeater and Bridge mode,
another using Repeater and Bridge mode), and also have wired link separately,
these two APs are also working as ì

bridgingî

for the two wired links.

Service Set Identifier (SSID)

An identifier that is attached to packets sent over the wireless LAN and functions as
a password for joining a particular radio cell; i.e., Basic Service Set (BSS).

Session Key

Session keys are unique to each client, and are used to authenticate a client
connection, and correlate traffic passing between a specific client and the access
point.

Shared Key

A shared key can be used to authenticate each client attached to a wireless network.
Shared Key authentication must be used along with the 802.11 Wireless Equivalent
Privacy algorithm.

Simple Network Time Protocol (SNTP)

SNTP allows a device to set its internal clock based on periodic updates from a
Network Time Protocol (NTP) server. Updates can be requested from a specific NTP
server, or can be received via broadcasts sent by NTP servers.

Temporal Key Integrity Protocol (TKIP)

A data encryption method designed as a replacement for WEP. TKIP avoids the
problems of WEP static keys by dynamically changing data encryption keys.

Trivial File Transfer Protocol (TFTP)

A TCP/IP protocol commonly used for software downloads.

Virtual Access Point (VAP)

Virtual AP technology multiplies the number of Access Points present within the RF
footprint of a single physical access device. With Virtual AP technology, WLAN users
within the deviceís footprint can associate with what appears to be different access
points and their associated network services. All the services are delivered using a

Glossary-3

Glossary

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 the instructions, may cause
harmful interference to radio communications. 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 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. 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.

You are cautioned that changes or modifications not expressly approved by the party responsible for compliance
could void your authority to operate the equipment.

single radio channel, enabling Virtual AP technology to optimize the use of limited
WLAN radio spectrum.

Wi-Fi Protected Access

WPA employs 802.1X as its basic framework for user authentication and dynamic
key management to provide an enhanced security solution for 802.11 wireless
networks.

Wired Equivalent Privacy (WEP)

WEP is based on the use of security keys and the popular RC4 encryption
algorithm. Wireless devices without a valid WEP key will be excluded from network

traffic.

WPA Pre-shared Key (WPA-PSK)

WPA-PSK can be used for small office networks with a limited number of users that
may not need a high level of security. WPA-PSK provides a simple security
implementation that uses just a pre-shared password for network access.

Glossary-4