Draytek Vigor2120 series User Manual page 237

Available settings are explained as follows:
Item
Enable the QoS Control
WAN Inbound
Bandwidth
WAN Outbound
Bandwidth
Reserved Bandwidth
Ratio
Enable UDP Bandwidth
Control
Outbound TCP ACK
Prioritize
Limited_bandwidth Ratio
Note: The rate of outbound/inbound must be smaller than the real bandwidth to ensure
correct calculation of QoS. It is suggested to set the bandwidth value for inbound/outbound
as 80% - 85% of physical network speed provided by ISP to maximize the QoS
performance.
Description
The factory default for this setting is checked.
Please also define which traffic the QoS Control settings
will apply to.
IN - apply to incoming traffic only.
OUT - apply to outgoing traffic only.
BOTH - apply to both incoming and outgoing traffic.
Check this box and click OK, then click Setup link again.
You will see the Online Statistics link appearing on this
page.
It allows you to set the connecting rate of data input for
WAN interface. For example, if your ADSL supports 1M of
downstream and 256K upstream, please set 1000kbps for
this box. The default value is 10000kbps.
It allows you to set the connecting rate of data output for
WAN interface. For example, if your ADSL supports 1M of
downstream and 256K upstream, please set 256kbps for this
box. The default value is 10000kbps.
It is reserved for the group index in the form of ratio of
reserved bandwidth to upstream speed and reserved
bandwidth to downstream speed.
Check this and set the limited bandwidth ratio on the right
field. This is a protection of TCP application traffic since
UDP application traffic such as streaming video will
exhaust lots of bandwidth.
The difference in bandwidth between download and upload
are great in ADSL2+ environment. For the download speed
might be impacted by the uploading TCP ACK, you can
check this box to push ACK of upload faster to speed the
network traffic.
The ratio typed here is reserved for limited bandwidth of
UDP application.
227
Vigor2120 Series User's Guide