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Smart Bandwidth Limit

Click this radio button to configure the default limitation for

bandwidth.

When session number exceeds –

type the value here as a

threshold to apply the smart bandwidth limit.

TX limit

- Define the default speed of the upstream for

each computer in LAN.

RX limit

- Define the default speed of the downstream for

each computer in LAN.

User-defined Bandwidth

Limit

Click this radio button to configure the user-defined

limitation for bandwidth.

Limitation List

- Display a list of specific limitations that

you set on this web page.

Start IP

- Bandwidth limit can be applied on certain IP

range. That’s, only the PCs within the range will be

influenced by the bandwidth limitation set here. Please

define the start IP address for the specific limitation.

End IP

- Define the end IP address for the specific

limitation.

TX Limit

- Define the limitation for the speed of the

upstream to be applied as specific limitation. 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 to be applied as specific limitation. 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

- Allows you to edit the settings for the selected

limitation.

Delete

- Remove the selected settings existing on the

limitation list.

When you finish adding a new bandwidth limit, simply click

OK

.

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3.4.3 Port Rate Control

A policer can limit the bandwidth of received frames. It is located in front of the ingress queue.

And a shaper can limit the bandwidth of transmitted frames. It is located after the ingress

queues. This page allows you to configure the switch port rate limit for Policers and Shapers.

Port

Represent LAN or WAN interface.

Policer Enabled

Check this box to enable policer function.

Policer Rate(Rx)

Type the number for policer function. The default value is 500.

It is restricted to 500-1000000 when the Policer Unit is set in

kbps, and it is restricted to 1-1000 when the Policer Unit is set

in Mbps.

Policer Unit

Determine the unit (kbps/Mbps) for policer.

Shaper Enabled

Check this box to enable shaper function.

Shaper Rate (Tx)

Type the number for shaper function. The default value is 500.

It is restricted to 500-1000000 when the Shaper Unit is set in

kbps, and it is restricted to 1-1000 when the Shaper Unit is set

in Mbps.

Shaper Unit

Determine the unit (kbps/Mbps) for shaper function.

3.4.4 QoS Control List

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.

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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.

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

QoS Control List

(QCL) to open the web page.

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QCE Type

Display the type of that QCE (QoS Control Entries).

Type Value

Display the value specified for the QCE.

Traffic Class

Display the class of the data transmission for the QCE.

QoS Control List allows users to set up to

five

groups of QCL. Each QCL group can contain

12 QCE settings.

Adding a New QCE

Click

to add a new QCE onto this page. Different QCE type will bring out different web

settings.

z

If you choose

Ethernet Type

as QCE Type, you have to type value for it and specify

traffic class from Low, Normal, Medium and High.

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Ethernet Type Value

Either

8~63

ASCII characters, such as 012345678(or 64

Hexadecimal digits leading by 0x, such as "0x321253abcde...").

z

If you choose

VLAN ID

as QCE Type, you have to type the ID number for it and specify

traffic class from Low, Normal, Medium and High.

z

If you choose

TCP/UDP Port

as QCE Type, you have to type the port number for it and

specify traffic class from Low, Normal, Medium and High.

TCP/UDP Port

Click

Single

or

Range

. If you select Range, you have to type

in the starting port number and the end porting number on

the boxes below.

TCP/UDP Port Range

Type in the starting port number and the end porting number

here if you choose Range as the type.

z

If you choose

DSCP

as QCE Type, you have to type value for it and specify traffic class

from Low, Normal, Medium and High.