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Configuring QoS settings

To configure Quality of Service (QoS) on the IP VCR for audio and video, go to Network > QoS.

QoS is a term that refers to a network's ability to customize the treatment of specific classes of data. For example, QoS can be used to prioritize audio transmissions and video transmissions over HTTP traffic. These settings affect all audio and video packets to H.323 and SIP endpoints, and to streaming viewers. All other packets are sent with a QoS of 0.

The IP VCR allows you to set six bits that can be interpreted by networks as either Type of Service (ToS) or Differentiated Services (DiffServ).

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Note: Do not alter the QoS settings unless you need to do so.

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To configure the QoS settings you need to enter a six bit binary value.

Further information about QoS, including values for ToS and DiffServ, can be found in the following RFCs, available on the Internet Engineering Task Force web site www.ietf.org:

• RFC 791
• RFC 2474
• RFC 2597
• RFC 3246

On this page:

• About QoS configuration settings
• ToS configuration
• DiffServ configuration
• Default settings

About QoS configuration settings

The table below describes the settings on the Network > QoS page.

Click Update QoS settings after making any changes.

Field	Field description	Usage tips
Audio	Six bit binary field for prioritizing audio data packets on the network.	Do not alter this setting unless you need to.
Video	Six bit binary field for prioritizing video data packets on the network.	Do not alter this setting unless you need to.

ToS configuration

ToS configuration represents a tradeoff between the abstract parameters of precedence, delay, throughput, and reliability.

ToS uses six out of a possible eight bits. The IP VCR allows you to set bits 0 to 5, and will place zeros for bits 6 and 7.

• Bits 0-2 set IP precedence (the priority of the packet).
• Bit 3 sets delay: 0 = normal delay, 1 = low delay.
• Bit 4 sets throughput: 0 = normal throughput, 1 = high throughput.
• Bit 5 sets reliability: 0 = normal reliability, 1 = high reliability.
• Bits 6-7 are reserved for future use and cannot be set using the IP VCR interface.

You need to create a balance by assigning priority to audio and video packets whilst not causing undue delay to other packets on the network. For example, do not set every value to 1.

DiffServ configuration

DiffServ uses six out of a possible eight bits to set a codepoint. (There are 64 possible codepoints.) The IP VCR allows you to set bits 0 to 5, and will place zeros for bits 6 and 7. The codepoint is interpreted by DiffServ nodes to determine how the packet is treated.

Default settings

The default settings for QoS are:

• Audio 101110:
  • For ToS, this means IP precedence is set to 5 giving relatively high priority. Delay is set to low, throughput is set to high, and reliability is set to normal.
  • For Diff Serv, this means expedited forwarding.
• Video 100010:
  • For ToS, this means IP precedence is set to 4 giving quite high priority (but not quite as high as the audio precedence). Delay is set to normal, throughput is set to high, and reliability is set to normal.
  • For DiffServ, this means assured forwarding (codepoint 41).

To return the settings to the default settings, click Reset to default.

Related topics

• Configuring network settings