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RUGGEDCOM WIN
User Guide
Separate service flows can be established for uplink and downlink traffic, where each service flow is assigned
a unique service level category and separate QoS settings. This feature allows segregation of high-speed/high-
priority traffic from less time-critical flows.
CONTENTS
•
Section 1.8.1, "Service Flow Classification"
•
Section 1.8.2, "Default Service Flows"
•
Section 1.8.3, "Scheduling"
Section 1.8.1
Service Flow Classification
Data packets are forwarded based on classification rules. Classification rules examine each packet for pattern
matches such as destination address, source address, IP TOS, or VLAN tag. All classification is defined at the base
station and the classification parameters are downloaded to the subscriber.
Section 1.8.2
Default Service Flows
Default uplink and downlink service flows are created automatically for each registered subscriber. These service
flows are used to pass all traffic not matching any user-defined service flow (such as broadcast ARP) between the
base station and subscribers. The default service flow capacity is limited for each subscriber.
Section 1.8.3
Scheduling
The base station enforces QoS settings for each service flow by controlling all uplink and downlink traffic
scheduling. This provides a non-contention based traffic model with predictable transmission characteristics. By
analyzing the total of all requests from all subscribers, the base station ensures that uplink and downlink traffic
conforms to the current service level agreements (SLAs). Centralized scheduling increases predictability of traffic,
eliminates contention, and provides the maximum opportunity for reducing overhead.
A regular period is scheduled for subscribers to register with the base station. These subscribers may be newly
commissioned or have been deregistered due to service outage or interference on the wireless interface. This is
the only opportunity for multiple subscribers to transmit simultaneously.
• Real-Time Polling Service (rt-PS)
The base station schedules a continuous regular series of transmit opportunities for the subscriber to send
variable size data packets. The grant size is based on the current data transfer requirement. Typical applications
include streaming MPEG video or VOIP with silence suppression. This is efficient for applications that have a
real-time component and continuously changing bandwidth requirements.
• Extended Real-Time Polling Service (ert-PS)
The base station schedules a continuous series of transmit opportunities for the subscriber to send variable
size data packets. This schedule supports real-time applications including VoIP with silence suppression. The
dynamically scheduled grants guarantee reserved bandwidth and reduce latency introduced by repetitive grant
requests. The service flow will not transmit packets larger than the nominal grant interval.
Service Flow Classification
Chapter 1
Introduction
7
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