Allied Telesis AT-WR4662n Operating manual

PN 613-001765 Rev.A 1
Introduction
This How to Note provides a brief description of the Wireless Distribution System (WDS)
technology along with a simple configuration example.
WDSs are flexible and scalable, therefore, the simple configuration example provided could
easily be extended to cover a wider range of installation scenarios.
For a complete description of the commands used in this configuration, please refer to the
document titled:
“AT-WR4600 Series –Command Reference Guide”.
What information will you find in this document?
This document provides information about how to configure:
Wireless LANs
Wired LAN interconnection via WDS
Cell size expansion via WDS
Which products and software version does it apply to?
This document applies to the following Allied Telesis products and software versions:
Product
Software Version
Description and Notes
AT-WR4662n
1.1-b254 onward
High-Speed Mobility –Wireless base router
IEEE 802.11 a/b/g/n dual radio, 2x2 MIMO
AT-WR4652-80
1.1-b254 onward
High-Speed Mobility –Wireless mobile router
IEEE 802.11 a/b/g/n dual radio, 1x1 MIMO
AT-TQ00xx
Cables and accessories
Note: Selection is application dependent
AT-6101G
IEEE 802.3af Gigabit Ethernet PoE Injector
Note: Use it to connect an AT-WR4662n
How To | Configure a Wireless Distribution System

PN 613-001765 Rev.A 2
Contents
Introduction ...........................................................................................................................................1
What information will you find in this document?................................................................................1
Which products and software version does it apply to? .....................................................................1
Overview ................................................................................................................................................3
What is a Wireless Distribution System?............................................................................................3
Why use a Wireless Distribution System?..........................................................................................3
How do the nodes in a Wireless Distribution System work? ..............................................................4
Configuring a Wireless Distribution System......................................................................................5
Connecting AT-WR4600 products.......................................................................................................7
Accessing the device via SSH............................................................................................................7
Accessing the device via RS-232.......................................................................................................7
Configuration examples .......................................................................................................................9
Wireless LAN.........................................................................................................................................9
Common setup..................................................................................................................................10
[P1] station role: root access-point ...................................................................................................10
[STA1] station role: workgroup-bridge..............................................................................................10
[STA2] station role: workgroup-bridge..............................................................................................10
Wired LAN interconnection via WDS ................................................................................................11
Common setup..................................................................................................................................12
[Bridge0] station role: root bridge......................................................................................................12
[Repeater] station role: repeater.......................................................................................................12
[Bridge1] station role: non-root bridge ..............................................................................................13
[Bridge2] station role: non-root bridge ..............................................................................................13
Cell size expansion via WDS .............................................................................................................14
Common setup..................................................................................................................................14
[Bridge0] station role: root bridge......................................................................................................14
[Repeater] station role: repeater.......................................................................................................15
[Bridge1] station role: non-root bridge ..............................................................................................15
[Bridge2] station role: non-root bridge ..............................................................................................16

PN 613-001765 Rev.A 3
Overview
What is a Wireless Distribution System?
A Wireless Distribution System (WDS) is the use of wireless repeating and bridging to
interconnect Access Points (APs) in an IEEE 802.11 Ethernet network.
A WDS can expand a wireless network without the traditional requirement for a wired
backbone. As long as the APs are on the same channel, WDSs provide a seamless
experience for roaming clients and for managing multiple wireless networks. The most
common use of a wireless distribution system is to bridge a WLAN spanning two buildings.
APs (such as routers or standalone devices) interconnect using radio frequency links using
the following modes:
Wireless bridging –where one AP acts as the common link between multiple APs.
The common AP communicates with other clients and repeaters.
Wireless repeating –where APs communicate with each other that are far apart, by
repeating signals using a wireless connection. This is similar to a regular Ethernet
bridge operation, and works best when APs have the same Service Set Identifier
(SSID).
Why use a Wireless Distribution System?
WDSs offer flexibility at low cost and are used in many situations where interconnectivity is
required without the use of physical connections.
WDSs have the advantage of being:
Cost effective –they reduce the need for cabling to inaccesible locations, and allow a
device to roam among several APs without having to rejoin networks. Network
design is a trade-off between investment cost of infrastructure and the efficiency of
RF cells. CAPEX increases due to the many cells required to cover a wide area, so
cost reduction may be accomplished by deploying big sized cells, but to the detriment
of available bandwidth.
Flexible and scalable –they extend existing WDSs easily, through the addition of
access points without the need for a backbone to link them.

PN 613-001765 Rev.A 4
How do the nodes in a Wireless Distribution System work?
The WLAN nodes may be classified as “root”, “non-root” and “repeater” nodes.
A “root” node is connected to the core network via either wired lines or a wireless link on a
different channel.
“non-root” nodes are connected to the core network via the “root” node and optionally
through the agency of a “repeater” via wireless multi-hop relay.
Note: Any wireless node halves the effective throughput, because all nodes share the same wireless
medium and the access point has to retransmit the information between the client side and the root
access point. Do not deploy WDS with more than two hops (“repeater” + “non-root bridge”).
All wireless nodes in the WDS must have the same authentication and encryption methods.
The “root” node is the master device and it selects the designated channel. All the other
nodes will hook on to the designated channel using RF scanning.

PN 613-001765 Rev.A 5
Configuring a Wireless Distribution System
Use the station-role command to set the role of the radio interface:
station-role non-root bridge (wireless-clients)
station-role repeater
station-role root [access-point|bridge (wireless-clients)]
station-role workgroup-bridge
no station-role
The available station-role command parameters are:
non-root bridge
Specifies that the access point or bridge operates as a “non-root” bridge and must associate
to a “root” bridge or a repeater to reach the core network. Note, this is the default for “non-
root” mode operations.
non-root bridge wireless-client
Specifies that the “non-root” bridge mode accepts associations from client devices.
repeater
Specifies that the access point is configured for repeating operations; the access point relays
wireless data packets between “root”and “non-root” bridges.
root access-point
Specifies that the access point is connected to a wired LAN and does not perform WDS
operations. Note, this is the default for “root” mode operations.
root bridge
Specifies that the access point or bridge operates as the root bridge in a pair of bridges. This
mode does not support wireless client associations. Note, this option supports point-to-point
and multipoint bridge operations.
root bridge wireless-client
Specifies that the “root” bridge mode accepts associations from client devices.
workgroup-bridge
Specifies that the device operates in workgroup bridge mode, so the device associates to an
access point or bridge as a client and provides a wireless LAN connection for devices
connected to its Ethernet port.

PN 613-001765 Rev.A 6
Figure 1: below, shows the allowed associations among station-roles:
Figure 1: Allowed association among station roles:

PN 613-001765 Rev.A 7
Connecting AT-WR4600 products
There are two options for accessing the Command Line Interface of devices:
1. SSH remote shell, using any text-mode SSH client software.
2. RS-232 DTE console interface; note, this is optional and is not always available.
Accessing the device via SSH
The Secure Shell (SSH) is an encrypted networking protocol, allowing users to configure the
device through an Ethernet network. Microsoft does not supply an SSH tool, you can use an
alternative program such as Tera Term Pro, which is licensed under GPL2. The device is
factory configured with the static IP address 192.168.1.1. If the device is receiving an IP
address from a DHCP server, please check the assigned IP address.
Accessing the device via RS-232
To access the device via RS-232, you can use either the built-in Microsoft HyperTerminal
(note it was removed from Windows Vista and later versions) or an alternative program such
as Tera Term Pro.
RS-232 Option
Setting
Transmission rate
115200bps
Data length
8 bit
Stop bit
1 bit
Parity
None
Flow control
None

PN 613-001765 Rev.A 8
Accessing the CLI
When logging into the device via a terminal console in SSH or RS-232, a login prompt is
displayed.
Note: By default, the login user name is manager and the password is friend.
AT-WR4600 login: manager
Password:
Feb 9 10:35:07 AT-WR4600 auth.info login[6898]: root login on 'ttyS0'
AA TTTTTTTTTTTTTTTTTT ooooo
AAAAA TTTTTTTTTTTTTTT oooooooo
AAAAAAAA TTTTTTTT I oooooo
AAAAAAAAAAA TTTTTTT IIIIIIIIII
AAAAAAA AAAAA TTTT IIIIIIIIII
AAAAAAA AAAAA T IIIIIIIIII
Copyright (C) 2012 Allied Telesis International
All rights reserved.
AT-WR4600> enable
Password:
AT-WR4600#

PN 613-001765 Rev.A 9
Configuration examples
Configuration examples start with the Command Line Interface already set to Global
configuration mode:
AT-WR4600# configure terminal
AT-WR4600(config)#
On setup completion, run the command show running-config to verify the applied
configuration.
Note: This example provides the minimum set of commands that are useful to configure the station
roles and does not include configuratoin for other services like bridging and security etc.
Wireless LAN
This example depicts a simple wireless network without a Wireless Distribution System.
STA
AP
AP1
STA1
STA
STA2
Figure 2: Wireless LAN

PN 613-001765 Rev.A 10
Common setup
Enter the following commands to restore the factory configuration for bridged mode:
AT-WR4600# copy nvram:/factory-config-routed startup-config
AT-WR4600# reload
Configure the common SSID for open authentication:
AT-WR4600(config)# dot11 ssid ATIopen
AT-WR4600(config-ssid)# authentication open
AT-WR4600(config-ssid)# guest-mode
AT-WR4600(config-ssid)# exit
Note: In this example network, each node belongs to a different wired LAN (subnet). You may build
the same wireless service using bridged mode, so that all nodes are all in the same subnet.
[P1] station role: root access-point
Configure the station role; assign the IP address and the SSID to the radio interface:
AT-WR4600(config)# interface dot11radio 0
AT-WR4600(config-if)# station-role root access-point
AT-WR4600(config-if)# ip address 10.0.0.100/24
AT-WR4600(config-if)# ssid ATIopen
AT-WR4600(config-if)# no shutdown
AT-WR4600(config-if)# end
[STA1] station role: workgroup-bridge
Configure the station role; assign the IP address and the SSID to the radio interface:
AT-WR4600(config)# interface dot11radio 0
AT-WR4600(config-if)# station-role workgroup bridge
AT-WR4600(config-if)# ip address 10.0.0.1/24
AT-WR4600(config-if)# ssid ATIopen
AT-WR4600(config-if)# no shutdown
AT-WR4600(config-if)# end
[STA2] station role: workgroup-bridge
Configure the station role; assign the IP address and the SSID to the radio interface:
AT-WR4600(config)# interface dot11radio 0
AT-WR4600(config-if)# station-role workgroup bridge
AT-WR4600(config-if)# ip address 10.0.0.2/24
AT-WR4600(config-if)# ssid ATIopen
AT-WR4600(config-if)# no shutdown
AT-WR4600(config-if)# end