Chapter 5 Wireless LAN

NBG334W User’s Guide

76

5.2.3

User Authentication

You can make every user log in to the wireless network before they can use it. This is called

user authentication. However, every wireless client in the wireless network has to support

IEEE 802.1x to do this.

For wireless networks, there are two typical places to store the user names and passwords for

each user.

•

In the AP: this feature is called a local user database or a local database.

•

In a RADIUS server: this is a server used in businesses more than in homes.

If your AP does not provide a local user database and if you do not have a RADIUS server,

you cannot set up user names and passwords for your users.

Unauthorized devices can still see the information that is sent in the wireless network, even if

they cannot use the wireless network. Furthermore, there are ways for unauthorized wireless

users to get a valid user name and password. Then, they can use that user name and password

to use the wireless network.

Local user databases also have an additional limitation that is explained in the next section.

5.2.4

Encryption

Wireless networks can use encryption to protect the information that is sent in the wireless

network. Encryption is like a secret code. If you do not know the secret code, you cannot

understand the message.

The types of encryption you can choose depend on the type of user authentication. (See

Section 5.2.3 on page 76

for information about this.)

For example, if the wireless network has a RADIUS server, you can choose

WPA

or

WPA2

. If

users do not log in to the wireless network, you can choose no encryption,

Static WEP

,

WPA-

PSK

, or

WPA2-PSK

.

Usually, you should set up the strongest encryption that every wireless client in the wireless

network supports. For example, suppose the AP does not have a local user database, and you

do not have a RADIUS server. Therefore, there is no user authentication. Suppose the wireless

network has two wireless clients. Device A only supports WEP, and device B supports WEP

and WPA. Therefore, you should set up

Static WEP

in the wireless network.

Table 25

Types of Encryption for Each Type of Authentication

NO AUTHENTICATION

RADIUS SERVER

Weakest

No Security

WPA

Static WEP

WPA-PSK

Strongest

WPA2-PSK

WPA2

Chapter 5 Wireless LAN

NBG334W User’s Guide

77

"

It is recommended that wireless networks use

WPA-PSK

,

WPA

, or stronger

encryption. IEEE 802.1x and WEP encryption are better than none at all, but it

is still possible for unauthorized devices to figure out the original information

pretty quickly.

It is not possible to use

WPA-PSK

,

WPA

or stronger encryption with a local

user database. In this case, it is better to set up stronger encryption with no

authentication than to set up weaker encryption with the local user database.

When you select

WPA2

or

WPA2-PSK

in your NBG334W, you can also select an option

(

WPA Compatible

) to support WPA as well. In this case, if some wireless clients support

WPA and some support WPA2, you should set up

WPA2-PSK

or

WPA2

(depending on the

type of wireless network login) and select the

WPA Compatible

option in the NBG334W.

Many types of encryption use a key to protect the information in the wireless network. The

longer the key, the stronger the encryption. Every wireless client in the wireless network must

have the same key.

5.3

Roaming

A wireless station is a device with an IEEE 802.11a/b/g compliant wireless interface. An

access point (AP) acts as a bridge between the wireless and wired networks. An AP creates its

own wireless coverage area. A wireless station can associate with a particular access point

only if it is within the access point’s coverage area.

In a network environment with multiple access points, wireless stations are able to switch from

one access point to another as they move between the coverage areas. This is known as

roaming. As the wireless station moves from place to place, it is responsible for choosing the

most appropriate access point depending on the signal strength, network utilization or other

factors.

The roaming feature on the access points allows the access points to relay information about

the wireless stations to each other. When a wireless station moves from a coverage area to

another, it scans and uses the channel of a new access point, which then informs the other

access points on the LAN about the change. An example is shown in

Figure 34 on page 78

.

With roaming, a wireless LAN mobile user enjoys a continuous connection to the wired

network through an access point while moving around the wireless LAN.

Enable roaming to exchange the latest bridge information of all wireless stations between APs

when a wireless station moves between coverage areas. Wireless stations can still associate

with other APs even if you disable roaming. Enabling roaming ensures correct traffic

forwarding (bridge tables are updated) and maximum AP efficiency. The AP deletes records of

wireless stations that associate with other APs (Non-ZyXEL APs may not be able to perform

this). 802.1x authentication information is not exchanged (at the time of writing).

Chapter 5 Wireless LAN

NBG334W User’s Guide

78

Figure 34

Roaming Example

The steps below describe the roaming process.

1

Wireless station

Y

moves from the coverage area of access point

AP 1

to that of access

point

AP 2

.

2

Wireless station

Y

scans and detects the signal of access point

AP 2

.

3

Wireless station

Y

sends an association request to access point

AP 2

.

4

Access point

AP 2

acknowledges the presence of wireless station

Y

and relays this

information to access point

AP 1

through the wired LAN.

5

Access point

AP 1

updates the new position of wireless station

Y

.

5.3.1

Requirements for Roaming

The following requirements must be met in order for wireless stations to roam between the

coverage areas.

1

All the access points must be on the same subnet and configured with the same ESSID.

2

If IEEE 802.1x user authentication is enabled and to be done locally on the access point,

the new access point must have the user profile for the wireless station.

3

The adjacent access points should use different radio channels when their coverage areas

overlap.

4

All access points must use the same port number to relay roaming information.

5

The access points must be connected to the Ethernet and be able to get IP addresses from

a DHCP server if using dynamic IP address assignment.

5.4

Quality of Service

This section discusses the Quality of Service (QoS) features available on the NBG334W.

Chapter 5 Wireless LAN

NBG334W User’s Guide

79

5.4.1

WMM QoS

WMM (Wi-Fi MultiMedia) QoS (Quality of Service) ensures quality of service in wireless

networks. It controls WLAN transmission priority on packets to be transmitted over the

wireless network.

WMM QoS prioritizes wireless traffic according to delivery requirements. WMM QoS is a

part of the IEEE 802.11e QoS enhancement to certified Wi-Fi wireless networks.

On APs without WMM QoS, all traffic streams are given the same access priority to the

wireless network. If the introduction of another traffic stream creates a data transmission

demand that exceeds the current network capacity, then the new traffic stream reduces the

throughput of the other traffic streams.

The NBG334W uses WMM QoS to prioritize traffic streams according to the IEEE 802.1q tag

or DSCP information in each packet’s header. The NBG334W automatically determines the

priority to use for an individual traffic stream. This prevents reductions in data transmission

for applications that are sensitive to latency (delay) and jitter (variations in delay).

5.4.1.1

WMM QoS Priorities

The following table describes the WMM QoS priority levels that the NBG334W uses.

5.5

General Wireless LAN Screen

"

If you are configuring the NBG334W from a computer connected to the

wireless LAN and you change the NBG334W’s SSID, channel or security

settings, you will lose your wireless connection when you press

Apply

to

confirm. You must then change the wireless settings of your computer to

match the NBG334W’s new settings.

Click

Network

>

Wireless LAN

to open the

General

screen.

Table 26

WMM QoS Priorities

PRIORITY LEVEL

DESCRIPTION

voice

(WMM_VOICE)

Typically used for traffic that is especially sensitive to jitter. Use this priority

to reduce latency for improved voice quality.

video

(WMM_VIDEO)

Typically used for traffic which has some tolerance for jitter but needs to be

prioritized over other data traffic.

best effort

(WMM_BEST_EFFORT)

Typically used for traffic from applications or devices that lack QoS

capabilities. Use best effort priority for traffic that is less sensitive to latency,

but is affected by long delays, such as Internet surfing.

background

(WMM_BACKGROUND)

This is typically used for non-critical traffic such as bulk transfers and print

jobs that are allowed but that should not affect other applications and users.

Use background priority for applications that do not have strict latency and

throughput requirements.

Chapter 5 Wireless LAN

NBG334W User’s Guide

80

Figure 35

Network > Wireless LAN > General

The following table describes the general wireless LAN labels in this screen.

See the rest of this chapter for information on the other labels in this screen.

Table 27

Network > Wireless LAN > General

LABEL

DESCRIPTION

Enable

Wireless LAN

Click the check box to activate wireless LAN.

Name(SSID)

(Service Set IDentity) The SSID identifies the Service Set with which a wireless

station is associated. Wireless stations associating to the access point (AP) must

have the same SSID. Enter a descriptive name (up to 32 printable 7-bit ASCII

characters) for the wireless LAN.

Hide SSID

Select this check box to hide the SSID in the outgoing beacon frame so a station

cannot obtain the SSID through scanning using a site survey tool.

Channel

Selection

Set the operating frequency/channel depending on your particular region.

Select a channel from the drop-down list box. The options vary depending on

whether you are using A or B/G frequency band and the country you are in.

Refer to the Connection Wizard chapter for more information on channels.

Operating

Channel

This displays the channel the NBG334W is currently using.

Security Mode

Select

Static-WEP

,

WPA-PSK

,

WPA

,

WPA2-PSK

, or

WPA2

to add security on this

wireless network. The wireless clients which want to associate to this network must

have same wireless security settings as this device. After you select to use a

security, addional options appears in this screen. See

5.5.2

,

5.5.3

,

5.5.4

sections. Or

you can select

No Security

to allow any client to associate this network without

authentication.

Note: If you enable the WPS function, only

No Security

,

WPA-PSK

and

WPA2-PSK

are available in this option.

Apply

Click

Apply

to save your changes back to the NBG334W.

Reset

Click

Reset

to reload the previous configuration for this screen.