System Overview MP.11-R Installation and Management
Quality of Service (QoS)
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Type: BE or RtPS. Best Effort (BE) is the default scheduler which follows the FIFO queuing. Real time Polling
Scheduler (RtPS) is the advanced scheduler for time sensitive traffic like VoIP, Video traffic.
• Maximum Latency – specified in increments of 5 ms steps from a minimum of 5 ms up to a maximum of 100 ms
• Tolerable Jitter – specified in increments of 5 ms steps from a minimum of 0 ms up to the Maximum Latency (in ms)
• Traffic priority – zero (0) to seven (7), 0 being the lowest, 7 being the highest
• Maximum number of data messages in a burst – one (1) to four (4), which affects the percentage of the maximum
throughput of the system
• Activation state – Active; Inactive
Note that traffic priority refers to the prioritization of this specific Service Flow.
The software tries to deliver the packets within the specified latency and jitter requirements, relative to the moment of
receiving the packets in the unit. For delay-sensitive traffic the jitter must be equal to or less than the latency. A packet is
buffered until an interval of time equal to the difference between Latency and Jitter (Latency – Jitter) has elapsed. The
software will attempt to deliver the packet within a time window starting at (Latency – Jitter) until the maximum Latency
time is reached. If the SFC’s scheduling type is real-time polling (rtPS), and the packet is not delivered by that time, it will
be discarded. This can lead to loss of packets without reaching the maximum throughput of the wireless link. For
example, when the packets arrive in bursts on the Ethernet interface and the wireless interface is momentarily maxed
out, then the packets at the “end” of the burst may be timed out before they can be sent.
Users are able to set up their own traffic characteristics (MIR, CIR, latency, jitter, etc.) per service flow class to meet their
unique requirements. A good example is provided by the seven predefined SFCs:
1. UL-Unlimited BE
a. Scheduling Type = Best Effort
b. Service Flow Direction = Uplink
c. Initialization State = Active
d. Maximum Sustained Data Rate = 108000 Kbps
e. Minimum Reserved Traffic Rate= 0 Kbps
f. Traffic Priority = 0
2. DL-Unlimited BE (same as UL-Unlimited BE, except Service Flow Direction = Downlink)
3. UL-G711 20 ms VoIP rtPS
a. Schedule type = Real time Polling
b. Service Flow Direction = Uplink
c. Initialization State = Active
d. Maximum Sustained Data Rate = 88 Kbps
e. Minimum Reserved Traffic Rate = 88 Kbps
f. Maximum Latency = 20 milliseconds
g. Maximum Jitter = 20 milliseconds
h. Traffic Priority = 1
4. DL-G711 20 ms VoIP rtPS (same as UL-G711 20ms VoIP rtPS, except Service Flow Direction = Downlink)
5. UL-G729 20 ms VoIP rtPS (same as UL-G711 20ms VoIP rtPS, except Maximum Sustained Data Rate and Maximum
Reserved Traffic Rate = 64 Kbps)
6. DL-G729 20 ms VoIP rtPS (same as UL-G729 20ms VoIP rtPS, except Service Flow Direction = Downlink)
7. DL-2Mbps Video
a. Schedule type = Real time Polling
b. Service Flow Direction = Downlink
c. Initialization State = Active
d. Maximum Sustained Data Rate = 2 Mbps
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