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PT-7528-8MST-16TX-4GSFP-WV-WV
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Moxa PT-7528-8MST-16TX-4GSFP-WV-WV [55/116] Ieee 802 d traffic marking

PT-7528 Series Advanced Settings

4-35

measured power of PDs, Sum of allocated power (in blue color) indicates total allocated power, and Max of

allocated power (in red color) indicates the threshold of total PoE power output. The graph displays these

powers by showing Current (mA) versus Sec. (second), and it is refreshed frequently by the Refresh Rate.

Using Traffic Prioritization

The Moxa switch’s traffic prioritization capability provides Quality of Service (QoS) to your network by making

data delivery more reliable. You can prioritize traffic on your network to ensure that high priority data is

transmitted with minimum delay. Traffic can be controlled by a set of rules to obtain the required Quality of

Service for your network. The rules define different types of traffic and specify how each type should be treated

as it passes through the switch. The Moxa switch can inspect both IEEE 802.1p/1Q layer 2 CoS tags, and even

layer 3 TOS information to provide consistent classification of the entire network. The Moxa switch’s QoS

capability improves the performance and determinism of industrial networks for mission critical applications.

The Traffic Prioritization Concept

Traffic prioritization allows you to prioritize data so that time-sensitive and system-critical data can be

transferred smoothly and with minimal delay over a network. The benefits of using traffic prioritization are:

• Improve network performance by controlling a wide variety of traffic and managing congestion.

• Assign priorities to different categories of traffic. For example, set higher priorities for time-critical or

business-critical applications.

• Provide predictable throughput for multimedia applications, such as video conferencing or voice over IP,

and minimize traffic delay and jitter.

• Improve network performance as the amount of traffic grows. Doing so will reduce costs since it will not be

necessary to keep adding bandwidth to the network.

Traffic prioritization uses the four traffic queues that are present in your Moxa switch to ensure that high

priority traffic is forwarded on a different queue from lower priority traffic. Traffic prioritization provides Quality

of Service (QoS) to your network.

Moxa switch traffic prioritization depends on two industry-standard methods:

• IEEE 802.1D—a layer 2 marking scheme.

• Differentiated Services (DiffServ)—a layer 3 marking scheme.

IEEE 802.1D Traffic Marking

The IEEE Std 802.1D, 1998 Edition marking scheme, which is an enhancement to IEEE Std 802.1D, enables

Quality of Service on the LAN. Traffic service levels are defined in the IEEE 802.1Q 4-byte tag, which is used to

carry VLAN identification as well as IEEE 802.1p priority information. The 4-byte tag immediately follows the

destination MAC address and Source MAC address.

The IEEE Std 802.1D, 1998 Edition priority marking scheme assigns an IEEE 802.1p priority level between 0

and 7 to each frame. The priority marking scheme determines the level of service that this type of traffic should

receive. Refer to the table below for an example of how different traffic types can be mapped to the eight IEEE

802.1p priority levels.

IEEE 802.1p Priority Level IEEE 802.1D Traffic Type

0 Best Effort (default)

1 Background

2 Standard (spare)

3 Excellent Effort (business critical)

4 Controlled Load (streaming multimedia)

5 Video (interactive media); less than 100 milliseconds of latency and jitter

6 Voice (interactive voice); less than 10 milliseconds of latency and jitter

7 Network Control Reserved traffic

Moxa PT-7528-8MST-16TX-4GSFP-WV-WV [55/116] Ieee 802 d traffic marking

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