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downstream for each computer in LAN.
Allow auto adjustment
.- Check this box to make the
best utilization of available bandwidth.
Limitation List
Display a list of specific limitations that you set on this web
page.
Specific Limitation
Start IP -
Define the start IP address for limit bandwidth.
End IP -
Define the end IP address for limit bandwidth.
Each /Shared -
Select
Each
to make each IP within the
range of Start IP and End IP having the same speed defined
in TX limit and RX limit fields; select
Shared
to make all
the IPs within the range of Start IP and End IP share the
speed defined in TX limit and RX limit fields.
TX limit -
Define the limitation for the speed of the
upstream. If you do not set the limit in this field, the system
will use the default speed for the specific limitation you set
for each index.
RX limit -
Define the limitation for the speed of the
downstream. If you do not set the limit in this field, the
system will use the default speed for the specific limitation
you set for each index.
Add -
Add the specific speed limitation onto the list above.
Edit -
Allow you to edit the settings for the selected
limitation.
Delete -
Remove the selected settings existing on the
limitation list.
Smart Bandwidth Limit
Check this box to have the bandwidth limit determined by
the system automatically.
TX limit -
Define the limitation for the speed of the
upstream. If you do not set the limit in this field, the system
will use the default speed for the specific limitation you set
for each index.
RX limit -
Define the limitation for the speed of the
downstream. If you do not set the limit in this field, the
system will use the default speed for the specific limitation
you set for each index.
Time Schedule
Index (1-15) in Schedule Setup -
You can type in four sets
of time schedule for your request. All the schedules can be
set previously in
Application >> Schedule
web page and
you can use the number that you have set in that web page.
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3.9.3 Quality of Service
Deploying QoS (Quality of Service) management to guarantee that all applications receive the
service levels required and sufficient bandwidth to meet performance expectations is indeed
one important aspect of modern enterprise network.
One reason for QoS is that numerous TCP-based applications tend to continually increase their
transmission rate and consume all available bandwidth, which is called TCP slow start. If
other applications are not protected by QoS, it will detract much from their performance in the
overcrowded network. This is especially essential to those are low tolerant of loss, delay or
jitter (delay variation).
Another reason is due to congestions at network intersections where speeds of interconnected
circuits mismatch or traffic aggregates, packets will queue up and traffic can be throttled back
to a lower speed. If there’s no defined priority to specify which packets should be discarded
(or in another term “dropped”) from an overflowing queue, packets of sensitive applications
mentioned above might be the ones to drop off. How this will affect application performance?
There are two components within Primary configuration of QoS deployment:
Classification: Identifying low-latency or crucial applications and marking them for
high-priority service level enforcement throughout the network.
Scheduling: Based on classification of service level to assign packets to queues and
associated service types
The basic QoS implementation in Vigor routers is to classify and schedule packets based on
the service type information in the IP header. For instance, to ensure the connection with the
headquarter, a teleworker may enforce an index of QoS Control to reserve bandwidth for
HTTPS connection while using lots of application at the same time.
One more larger-scale implementation of QoS network is to apply DSCP (Differentiated
Service Code Point) and IP Precedence disciplines at Layer 3. Compared with legacy IP
Precedence that uses Type of Service (ToS) field in the IP header to define 8 service classes,
DSCP is a successor creating 64 classes possible with backward IP Precedence compatibility.
In a QoS-enabled network, or Differentiated Service (DiffServ or DS) framework, a DS
domain owner should sign a Service License Agreement (SLA) with other DS domain owners
to define the service level provided toward traffic from different domains. Then each DS node
in these domains will perform the priority treatment. This is called per-hop-behavior (PHB).
The definition of PHB includes Expedited Forwarding (EF), Assured Forwarding (AF), and
Best Effort (BE). AF defines the four classes of delivery (or forwarding) classes and three
levels of drop precedence in each class.
Vigor routers as edge routers of DS domain shall check the marked DSCP value in the IP
header of bypassing traffic, to allocate certain amount of resource execute appropriate policing,
classification or scheduling. The core routers in the backbone will do the same checking
before executing treatments in order to ensure service-level consistency throughout the whole
QoS-enabled network.
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However, each node may take different attitude toward packets with high priority marking
since it may bind with the business deal of SLA among different DS domain owners. It’s not
easy to achieve deterministic and consistent high-priority QoS traffic throughout the whole
network with merely Vigor router’s effort.
In the
Bandwidth Management
menu, click
Quality of Service
to open the web page.
Available settings are explained as follows:
Item
Description
General Setup
Index
Display the WAN interface number that you can edit.
Status
Display if the WAN interface is available for such
function or not.
Bandwidth
Display the inbound and outbound bandwidth
setting for the WAN interface.
Direction
Display which direction that such function will
influence.
Class 1/Class2/Class 3/Others
Display the bandwidth
percentage for each class.
UDP Bandwidth Control
Display the UDP bandwidth
control is enabled or not.
Online Statistics
Display an online statistics for quality of
service for your reference
Setup
Allow to configure general QoS setting for WAN
interface.
Class Rule
Index
Display the class number that you can edit.
Name
Display the name of the class.
Rule
Allow to configure detailed settings for the selected
Class.
Service Type
Allow to configure detailed settings for the
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Item
Description
service type.
Enable the First Priority
for VoIP SIP/RTP
When this feature is enabled, the VoIP SIP/UDP packets will
be sent with highest priority.
SIP UDP Port
Set a port number used for SIP.
This page displays the QoS settings result of the WAN interface. Click the
Setup
link to
access into next page for the general setup of WAN interface. As to class rule, simply click the
Edit
link to access into next for configuration.
You can configure general setup for the WAN interface, edit the Class Rule, and edit the
Service Type for the Class Rule for your request.
Online Statistics
Display an online statistics for quality of service for your reference. This feature is available
only when the Quality of Service for WAN interface is enabled.
General Setup for WAN Interface
When you click
Setup
, you can configure the bandwidth ratio for QoS of the WAN interface.
There are four queues allowed for QoS control. The first three (Class 1 to Class 3) class rules
can be adjusted for your necessity. Yet, the last one is reserved for the packets which are not
suitable for the user-defined class rules.
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Available settings are explained as follows:
Item
Description
Enable the QoS Control
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.
WAN Inbound
Bandwidth
It allows you to set the connecting rate of data input for
WAN2/WAN3. For example, if your ADSL supports 1M of
downstream and 256K upstream, please set 1000kbps for
this box. The default value is 10000kbps.
WAN Outbound
Bandwidth
It allows you to set the connecting rate of data output for
WAN2/WAN3. For example, if your ADSL supports 1M of
downstream and 256K upstream, please set 256kbps for this
box. The default value is 10000kbps.
Reserved Bandwidth
Ratio
It is reserved for the group index in the form of ratio of
reserved bandwidth to upstream speed
and
reserved
bandwidth to downstream speed
.
Enable UDP Bandwidth
Control
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.
Outbound TCP ACK
Prioritize
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

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