Obihai OBi110, Administration Manual

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Copyright 2010-2012 Obihai Technology, Inc. 70
on the WAN side within the port range in this rule with matching transport
protocol
QoS Settings
QoS only applies to upstream traffic to the WAN side. The QoS settings described here takes effect in router mode only. It is
based on Traffic Control(TC) and Hierarchy Token Bucket (HTB). Refer to the HTB home pages for details on TC and HTB
(
http://luxik.cdi.cz/~devik/qos/htb/ ).
Four priority classes of upstream traffic are defined in the OBi QoS policy: The Restricted class has the highest priority,
followed by the High, the Medium, and the Low classes. To fully utilize the upstream bandwidth, it is important to have a
relatively accurate upstream bandwidth estimation configured in the UpStreamBandwidth parameter; this tells the OBi the
total upstream bandwidth to allocate to the four priority classes.
The guaranteed uplink bandwidth for Restricted class traffic is configured in the RestrictedBandwidth parameter. The rest
of the upstream bandwidth (the UpStreamBandWidth less the RestrictedBandwidth) is divided among the High,
Medium,and Low classes proportionally according to the assigned weighting factor for each class in the configuration. Let
W
high
, W
medium
, and W
low
be the respective weight assigned to the High, Low, and Medium classes, the corresponding
guaranteed uplink bandwidth for each class is calculated using the following formulae:
BW
high
= (UpstreamBandwidth – RestrictedBandwidth) * W
high
/ (W
high
+ W
medium
+ W
low
) (Kbps)
BW
medium
= (UpstreamBandwidth – RestrictedBandwidth) * W
medium
/ (W
high
+ W
medium
+ W
low
) (Kbps)
BW
low
= (UpstreamBandwidth – RestrictedBandwidth) * W
low
/ (W
high
+ W
medium
+ W
low
) (Kbps)
The native voice related traffic is always classified as Restricted. Other network packets are classified based on the
Differentiated Service Code Point (DSCP) in their IP headers. The 64 possible DSCP codes (0 – 63) can be mapped into one
of the four priority classes using the configurable DSCP to Priority Class Mapping table.
Below is a screen shot of the QoS Settings web page.