QoS and QoS Policies
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Quality of Service Guide
3HE 11014 AAAC TQZZA Edition: 01
• 7705 SAR-M
All Ethernet access ports except those on the following modules:
− 8-port xDSL module
− GPON module
− 6-port DSL Combination module (SHDSL ports)
• 7705 SAR-H
− All Ethernet access ports except those on the 4-port SAR-H Fast Ethernet
module
• 7705 SAR-Hc
• 7705 SAR-W
• 7705 SAR-Wx
• 7705 SAR-X
3.1.7.2 H-QoS Example
A typical example in which H-QoS is used is where a transport provider uses a
7705 SAR as a PE device and sells 100 Mb/s of fixed bandwidth for point-to-point
Internet access, and offers premium treatment to 10% of the traffic. A customer can
mark up to 10% of their critical traffic such that it is classified into high-priority queues
and serviced prior to low-priority traffic.
Without H-QoS, there is no way to enforce a limit to ensure that the customer does
not exceed the leased 100 Mb/s bandwidth, as illustrated in the following two
scenarios.
• If a queue hosting high-priority traffic is serviced at 10 Mb/s and the low-priority
queue is serviced at 90 Mb/s, then at a moment when the customer transmits
less than 10 Mb/s of high-priority traffic, the customer bandwidth requirement is
not met (the transport provider transports less traffic than the contracted rate).
• If the scheduling rate for the high-priority queue is set to 10 Mb/s and the rate for
low-priority traffic is set to 100 Mb/s, then when the customer transmits both
high- and low-priority traffic, the aggregate amount of bandwidth consumed by
customer traffic exceeds the contracted rate of 100 Mb/s and the transport
provider transports more traffic than the contracted rate.
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