D-Link DES-6500 Router Manual PDF (Setup & Configuration Guide)

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D-Link DES-6500 Layer 3 Stackable Gigabit Ethernet Switch

53

down a loop when a storm is formed because a MAC address cannot be located in the

Switch’s forwarding database and it must send a packet to all ports or all ports on a VLAN.

To configure Traffic Control, select the

Unit

(Unit ID of a switch in a switch) you want to

configure.

Broadcast Storm

,

Multicast Storm

and

Destination Unknown

may be

Enabled

or

Disabled

. The

Threshold

value is the upper threshold at which the specified traffic control

is switched on.

This is the number of Broadcast, Multicast or DLF packets, in Kbps, received

by the switch that will trigger the storm traffic control measures. The Threshold value can be

set from 0 to 255 packets. The Default setting is 128.

Configuring Port Security

A given port’s (or a range of ports’) dynamic MAC address learning can be locked such that

the current source MAC addresses entered into the MAC address forwarding table can not be

changed once the port lock is enabled. The port can be locked by using the

Learn <

Disabled

>

pull-down menu to

Enabled

, and clicking

Apply

.

This is a security feature that prevents unauthorized computers (with source MAC addresses

unknown to the switch prior to locking the port (or ports) from connecting to the switch’s

locked ports and gaining access to the network.

Figure 4- 23. Port Security Settings window

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The following parameters can be set:

Parameter

Description

Unit

Allows you to specify a switch in a switch stack using that switch’s Unit ID.

From/To

A consecutive group of ports may be configured starting with the selected

port.

Admin State

This pull-down menu allows you to

Enable

or

Disable

Port Security

(locked MAC address table for the selected ports.)

Max.Addr(0-64)

The number of MAC addresses that will be in the MAC address forwarding

table for the selected switch and group of ports.

Mode

This pull-down menu allows you to select how the MAC address table

locking will be implemented on the switch, for the selected group of ports.

The options are

DeleteOnReset

and

DeleteOnTimeout

.

Configuring QoS

Understanding QoS

The DES-6500 supports 802.1p priority queuing. The switch has two priority queues. These

priority queues are labeled as 0, the high queue, and 6, the low queue. These priority queues,

specified in IEEE 802.1p are mapped to the switch’s priority queues as follows:

•

Priority 0 is assigned to the Switch’s Q2 queue.

•

Priority 1 is assigned to the Switch’s Q0 queue.

•

Priority 2 is assigned to the Switch’s Q1 queue.

•

Priority 3 is assigned to the Switch’s Q3 queue.

•

Priority 4 is assigned to the Switch’s Q4 queue.

•

Priority 5 is assigned to the Switch’s Q5 queue.

•

Priority 6 is assigned to the Switch’s Q6 queue.

•

Priority 7 is assigned to the Switch’s Q6 queue.

For strict priority-based scheduling, any packets residing in the higher priority queues are

transmitted first. Only when these queues are empty, are packets of lower priority transmitted.

For weighted round-robin queuing, the number of packets sent from each priority queue

depends upon the assigned weight.

For a configuration of 8 CoS queues, A~H with their respective weight value: 8~1, the

packets are sent in the following sequence: A1, B1, C1, D1, E1, F1, G1, H1, A2, B2, C2, D2,

E2, F2, G2, A3, B3, C3, D3, E3, F3, A4, B4, C4, D4, E4, A5, B5, C5, D5, A6, B6, C6, A7,

B7, A8, A1, B1, C1, D1, E1, F1, G1, H1.

For weighted round-robin queuing, if each CoS queue has the same weight value, then each

CoS queue has an equal opportunity to send packets just like round-robin queuing.

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For weighted round-robin queuing, if the weight for a CoS is set to 0, then it will continue

processing the packets from this CoS until there are no more packets for this CoS. The other

CoS queues that have been given a nonzero value, and depending upon the weight, will follow

a common weighted round-robin scheme.

Remember that the DES-6500 has 8 priority queues (and seven Classes of Service) for each

port on the switch.

Setting Bandwidth Control

The bandwidth control settings are used to place a ceiling on the transmitting and receiving

data rates for any selected port. In the

Configuration

folder open the

QoS

folder and click

Bandwidth Control

, to view the screen shown below.

Figure 4- 24. Bandwidth Settings window

The following parameters can be set or are displayed:

Parameter

Description

Unit

Allows you to specify a switch in a switch stack using that switch’s Unit ID.

From/To

A consecutive group of ports may be configured starting with the selected

port.

Type

This drop-down menu allows you to select between

RX

(receive,)

TX

(transmit,) and

Both

.

This setting will determine whether the bandwidth

ceiling is applied to receiving, transmitting, or both receiving and

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D-Link DES-6500 Layer 3 Stackable Gigabit Ethernet Switch

56

transmitting packets.

no_limit

This drop-down menu allows you to specify that the selected port will have

no bandwidth limit.

Enabled

disables the limit.

Rate

This field allows you to enter the data rate, in kb/s, that will be the limit for

the selected port.

Results of the

Bandwidth Settings

will be displayed directly below, in the

Port Bandwidth

Table

QoS Scheduling Mechanism Table

This drop-down menu allows you to select between a

Weight Fair

and a

Strict

mechanism

for emptying the priority queues. In the

Configuration

folder open the

QoS

folder and click

QoS Scheduling Mechanism

, to view the screen shown below.

Figure 4- 25. Scheduling Mechanism Configuration window

Click

Apply

to let your changes take effect.

The

Scheduling Mechanism

has the following parameters.

Parameter

Description

Strict

The highest queue is the first to process traffic. That is, the highest

queue should be finished at first.

Weight fair

Use the weight fair algorithm to handle packets in an even distribution

in priority queues.

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QoS Output Scheduling

QoS can be customized by changing the output scheduling used for the hardware queues in

the Switch. As with any changes to QoS implementation, careful consideration should be

given to how network traffic in lower priority queues is affected. Changes in scheduling may

result in unacceptable levels of packet loss or significant transmission delay. If you choose to

customize this setting, it is important to monitor network performance, especially during peak

demand, as bottlenecks can quickly develop if the QoS settings are not suitable. In the

Configuration

folder open the

QoS

folder and click

QoS Output Scheduling

, to view the

screen shown below.

Figure 4- 26. QoS Output Scheduling Configuration window

Once you have assigned a priority to the port groups on the switch, you can then assign this

Class to each of the 7 levels of 802.1p priorities.

Note

: The settings you assign to the queues, numbers 0-7,

represent the IEEE 802.1p priority tag number. Do not

confuse these settings with port numbers.

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