Overview of WMM (Wi-Fi Multimedia)

 

Multimedia applications in a Wi-Fi network require Quality of Service (QoS) functionality. QoS enables Wi-Fi access points to prioritize traffic and optimizes the way shared network resources are allocated among different applications. Without QoS, all applications running on different devices have equal opportunity to transmit data frames. That works well for data traffic from applications such as web browsers, file transfers, or email, but it is inadequate for multimedia applications. Voice over Internet Protocol (VoIP), video streaming, and interactive gaming are highly sensitive to latency increases and throughput reductions, and require QoS.

 

To meet this need, the Wi-Fi Alliance started interoperability certification for WMM (Wi-Fi Multimedia) as a profile of the upcoming IEEE 802.11e QoS extensions for 802.11 networks. WMM defines four access categories (voice, video, best effort, and background) that are used to prioritize traffic so that these applications have access to the necessary network resources. Additionally, WMM-enabled Wi-Fi networks concurrently support legacy devices that lack WMM functionality. The WMM best effort access category and legacy devices transmit with the same priority.

 

 

Overview of MBM (Multimedia Bandwidth Management)

Unlike the dial-up connectivity that has bandwidth limit, in today’s application like peer-to-peer file sharing, online game or VoIP services can easily consume the network bandwidth. In order to prevent the saturation of the network, ZyXEL has introduced MBM (Multimedia Bandwidth Management) that allows the users to facilitate dynamic bandwidth control with easy deployment.

In addition to that, the delay, jitter or packet loss when playing the online game with many players may hurt user’s experience. Degraded network QoS will influence online game player’s willingness to continue playing the game as they are less tolerant to any network delay while a few second delays in the FTP transmission will not have any significant negative impact on user’s feeling. The packets from the online game service are normally very delay sensitive compared to packets on FTP or Peer-to-Peer transmission that can tolerate a few seconds of delay. To secure the network QoS, vendors have developed many tools or soft wares; ZyXEL has launched the ATC (Automatic Traffic Classifier) that will automatically classify the outgoing traffic (WAN) into three data stream types--High, Middle, and Low class (Best Effort).

 

ATC (Automatic Traffic Classifier)

 

Let’s take a closer look at what is ATC. ATC by definition will group the traffic into three data streams. Real time packets such as VoIP or online service will be granted a high priority that will be categorized in the high queue and forwarded first. Non-real time packets normally are from applications such as FTP or Bit Torrent applications will be granted a lower priority that will be put in the middle or best-effort queue and forwarded after the real-time traffic.

 

 

Scenario: In the ABC Company’s Lobby, employee using internal VoIP and guests surffing internet

 

 

There are more and more companies provide their guests to surf internet in the lobby area when they visit company and waiting for someone. If this company implement the Wi-Fi SIP phone for their internal communication. How can they set up the wireless environment to let the guest surf internet meanwhile ensure the internal Wi-Fi phone quality.

 

In this scenario, we’ll use one  NWA-3100 to achieve this goal. The configuration in our device is quite easy. Just follow the steps below.

 

Notes: Here we assume both the Wi-Fi SIP phones and guests’ client laptops support Wi-Fi Multimedia(WMM).

 

Step 1

1.          Login NWA-3100 Web Configurator.

2.          Click WIRELESS on the left frame of page.

3.          And then click SSID on the top of this page.

4.          Select the profile “Index 3” and then click the Edit button.

 

Step 2

1.          Input the SSID profile name: Inter-VoIP

2.          Input this profile’s SSID: VoIP

3.          Select WMM_VOICE from the OoS drop-down list.

4.          Click the Apply button

 

 

 

Step 3

1.          Select the SSID profile index 4 same as Step 1’s screen to edit it.

2.          Input the SSID profile name: forGuest

3.          Input this profile’s SSID: Guest

4.          Select WMM_VOICE from the OoS drop-down list.

5.          Click the Apply button

 

 

 

Step 4: Backup to to SSID page, you’ll see the configuration like this.

 

 

 

Step 5: On the Wireless page

1.          Select the MBSSID from the drop-down list on Operation Mode.

2.          Select the SSID profile index 3 and index 4

3.          Click the Apply button

 

 

Now you have done all the setting on  NWA-3100.

 

Step 6: Wi-Fi Phone setting

For the Wi-Fi phone, you need to configure to let the Wi-Fi phone associate with the SSID = “VoIP”. This can make the voice has the high priority then the data transmitted on another SSID ( i.e. Guest)

 

Step 7: Guests’ Laptop Setting

The last thing to is let the vistors’ laptop connect to wireless network by using SSID = “Guest” !

 

Scenario 2: IF my Wi-Fi phone does not support Wi-Fi Multimedia(WMM), how can I configure to allocate the bandwidth with the high priority (QoS) for voice transmit?

 

Although your Wi-Fi devices do not support WMM, our  NWA-3100 provide another feature to achieve the quality of service(QoS) – Automatic Traffic Classfier(ATC).