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Quality of Service (QoS) Setup

In the pages of Quality of Service (QoS), parameters can be set in many queues in order to guarantee the high performance of the discriminated radio traffic such as Voice-over-IP (VoIP), audio, vedio, and streaming media.

QoS Setup

The Quality of Service (QoS) setup at SMT-R2000 means the parameters setup to the various categories of radio traffic and the efficient setup of maximum/minimum transmission wait time via Contention Windows. The setup items descirbed here affect the AP data transmission.

Notes

  • In case of Guest Interface, QoS Queue setup affects the whole AP load (Both of BSS).
  • Dual Band  AP의 경우, 이 설정들은 In case of Dual Band AP, these setups are applied to all 2.4GHz and 5hz radio. However, each radio traffic uses queues independently. (Guest traffic is an exception.)
  • The traffics of Internal network and Guest network always use the same queue. This is the same as the case in Dual Band.

QoS of AP uses the Type of Service (ToS) information of IP packet header. AP inspects the ToS area of IP header for all packets that pass through AP. The priorities of the packets are determined by the allocation of the packets into one of many queues according to the values of ToS area. The parameters that you will set determines how each queue processes the data packet.

The following menus are contained in the page of Quality of Service setup.

  • AP EDCA Parameter Setup
  • Wi-Fi Multimedia
  • Station EDCA Parameter Setup
  • Retry Number Setup
  • Priority Setup
  • Setup Update

    • AP EDCA Parameter Setup

    AP Enhanced Distributed Channel Access (EDCA) parameter affects the traffic that is transmitted from AP into the client.

    Item
    Description
    Queue
    Queue is defined according to the data types that are to be transmitted from AP into the clients.
    Data 0 (Voice)
    This data needs the high priority and little delay time. The data affected by time, such as VoIP and streaming, is transmitted into this queue.
    Data 1(Video)
    This data is a video data that needs the high priority and little delay time. The video data affected by time is transmitted into this queue.
    Data 2 (best effort)
    This data needs the middle-level priority, performance, and delay time. Most IP data are transmitted into this queue.
    Data 3 (Background)
    This data needs the lowest priority and the high performance. The bulk data that needs the maximized performance and that are little affected by time (Such as FTP data) are transmitted into this queue.
    For more information, refer to QoS Queues and Parameters to Coordinate Traffic Flow of IEEE 802.11e.
     
    AIFS
    (Inter-Frame Space)
    Arbitration Inter-Frame Spacing (AIFS) means the wait time (ms) for the data frame.
    AIFS is the value between 1 and 255.
    For more information, refer to DCF Control of Data Frames and Interfame Spaces of IEEE802.11.
     
    cwMin
    (Minimum Contention Window)
    This parameter is the input value of the algorithm that determines the early random backoff wait time ("window") value.
    The value designated at the Minimum Contention Window item is the maximum value of the initial random backoff wait time that is to be determined by the algorithm.
    The random figure that is firstly generated will be the one between 0 and the value defined at this item.
    When the random backoff wait time firstly generated before the transmission of the data frame expires, the retry counter increases, and the random backoff (window) value doubles. This process will be repeated until the size of the random backoff value reaches the value defined at the Maximum Contention Window item.
    The valid "cwmin" values are 1, 3, 7, 15, 31, 63, 127, 255, 511, or 1024. The value of "cwmin" should be less than that of "cwmin".
    For more information, refer to IEEE802.11 Random Backoff and Minimum / Maximum Contention Windows.
     
    cwMax
    (Maximum Contention Window)
    The value appointed by the Maximum Contention Window item is the maximum value that the random backoff value is multiplied. The random backoff value increases by double until the data frame is transmitted or the value reaches the Maximum value of Contention Window.
    Once the random backoff value reaches the Maximum Contention Window value, the retry will be repeated until it reaches the maximum retry number.
    The valid "cwmax" value is 1, 3, 7, 15, 31, 63, 127, 255, 511, or 1024. The value of "cwmax" should be larger than that of "cwmin".
    For more information, refer to Random Backoff and Minimum / Maximum Contention Windows of IEEE 802.11.
     
    Max. Burst Length
    AP EDCA Parameter Only (Max. Burst Length option is applied only to the traffic that is transmitted from AP into the client.)
    This value means the Maximum Burst Length (ms) that will be permitted for the burst packet to the radio network. Packet Burst is the set of the frames that are transmitted without the header information. By using the burst packet, the overhead can decrease, and the higher performance can be obtained as its result.
    The valid Max. Burst Length values are the ones between 0.0 and 999.9.
     

    Wi-Fi Multimedia

    In default setup, AP is set by using Wi-Fi MultiMedia (WMM). If WMM option is activated, the controlling function of the QoS priority and the access to the radio media are activated. By using WMM, QoS setup of SMT-R2000 controls the downstream traffic (AP ED A parameter) that is transmitted from AP into the client and the upstream traffic (station EDCA parameter) that is trasmitted from the client into AP.

    If WMM is set as 'non-used', the station EDCA parameter option will be released.

    Even though WMM is set as 'non-used', you can stil set some of the AP EDCA parameter options.

    Station EDCA Parameter Setup

    Station Enhanced Distributed Channel Access (EDCA) parameter affects the traffic transmitted from the client into AP.

    Item
    Description
    Queue
    Queue is defined according to the data types transmitted from the client into AP.
    Data 0 (Voice)
    This data needs the high priority and little delay time. The data affected by time, such as VoIP and streaming, is transmitted into this queue.
    Data 1(Video)
    This data is the video data that needs the high priority and little delay time. The video data affected by time is transmitted into this queue.
    Data 2 (best effort)
    This data needs the intermediate level priority, performance, and delay time. Most IP data are transmitted into this queue.
    Data 3 (Background)
    This data needs the lowest priority and the high performance. The bulk data that need the maximum performance and that are little affected by time, such as FTP data, are transmitted into this queue.
    For more information, refer to QoS Queues and Parameters to Coordinate Traffic Flow of IEEE 802.11e.
     
    AIFS
    (Inter-Frame Space)
    Arbitration Inter-Frame Spacing (AIFS) means the wait time (ms) for the data frame.
    For more information, refer to DCF Control of Data Frames and Interfame spaces of IEEE802.11.
     
    cwMin
    (Minimum Contention Window)
    This parameter is the input value of the algorithm that determines the early random backoff wait time ("window") value.
    The value designated at the Minimum Contention Window item is the maximum one of the early random backoff wait time that is to be determined by the algorithm.
    The random figure firstly generated will be the ones between 0 and the value defined at this item.
    If the random backoff wait time firstly generated before the transmission of the data frame expires, the retry counter increases, and the value of the random backoff (window) doubles. This process will be repeated until the value reaches the value defined at the Maximum Contention Window item.
    For more information, refer to Random Backoff and Minimum / Maximum Contention Windows of IEEE 802.11.
     
    cwMax
    (Maximum Contention Window)
    The value appointed by the Maximum Contention Window item is the maximum value that the random backoff value is multiplied. The random backoff value increases by doubles until the random backoff value reaches the maximum value of the Contention Window.
    Once the random backoff value reaches the one of Maximum Contention Window, the retries will continue until a maximum number of retries allowed is reached.
    Once the Maximum Contention Window size is reached, retries will continue until a maximum number of retries allowed is reached.
    For more information, refer to Random Backoff and Minimum / Maximum Contention Windows of IEEE 802.11.
     
    TXOP Limit
    Station EDCA Parameter Only (TXOP Limit option is applied only to the traffic transmitted from the client into AP.)
    Transmission Opportunity (TXOP) means the time interval that the WME client becomes to have the right to transmit the data.

    　

    Retry Number Setup

    AP has been set, as its default setup, to peprmit the retransmission number for the IP Data Packets into the determined value (Defalut: Six times). The retransmission packet is limited so that it can be provided only at IP

    The default retransmission value means the application to the IP packets not mentioned in the retry number list by ports.

    Retry Number List by Ports is the one where the protocol type (TCP/UDP) of the IP packet and the destination port no. are selected and the retry number for the relevant transmission packets are allocated. Retransmission List of IP Pakcet by Destination Ports can register up to 16 lists.

    Priority Setup

    Priority Level List by Ports is the one where the protocol types of IP packet and the destination port number are selected and the priority values (Within 0~7) for the relevant transmission packet are allocated. Priority List of IP Packets by Destination Ports can register up to 16 lists.

    Update settings

    The QoS setup can be updated as follows:

    1. Move to Service > QoS.
    2. Set the necessary QoS items.
    3. Click "Update" to apply the changes
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