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maximum number of Internet sessions permitted.
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.
4.8.2 Bandwidth Limit
The downstream or upstream from FTP, HTTP or some P2P applications will occupy large of
bandwidth and affect the applications for other programs. Please use Limit Bandwidth to make
the bandwidth usage more efficient.
In the
Bandwidth Management
menu, click
Bandwidth Limit
to open the web page.
To activate the function of limit bandwidth, simply click
Enable
and set the default upstream
and downstream limit.
Enable
Click this button to activate the function of limit bandwidth.
Apply to 2
nd
Subnet
Check this box to apply the bandwidth
limit to the second subnet specified in
LAN>>General Setup
.
Disable
Click this button to close the function of limit bandwidth.
Default TX limit
Define the default speed of the upstream for each computer in
LAN.
Default RX limit
Define the default speed of the downstream for each computer
in LAN.
Limitation List
Display a list of specific limitations that you set on this web
page.
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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.
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.
4.8.3 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:
z
Classification: Identifying low-latency or crucial applications and marking them for
high-priority service level enforcement throughout the network.
z
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.
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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, thus 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.
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.
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.
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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.
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.
Enable the QoS Control
The factory default for this setting is checked.
Please also define which traffic the QoS Control settings will
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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 WAN.
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
WAN. For example, if your ADSL supports 1M of
downstream and 256K upstream, please set 256kbps for this
box. The default value is 10000kbps.
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.
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 check this
box to push ACK of upload faster to speed the network traffic.
Limited_bandwidth Ratio
The ratio typed here is reserved for limited bandwidth of UDP
application.

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