D-Link DES-1218R [26/38] Flow control

DES-1218R/DES-1226R 10/100/1000 Mbps Ethernet Switch User’s Guide

When Auto is chosen, NWay will negotiate three settings:

♦ Speed – 10/100/1000

♦ Duplex - Full/Half

♦ IEEE 802.3x Flow Control – Enable/Disable

Flow Control

Toggles flow control Enable or Disable. It is useful during periods of heavy network activity when

the Switch’s buffers can receive too much traffic and fill up faster than the Switch can forward the

information. In such cases, the Switch will intervene and tell the transmitting device to pause to

allow the information in the port buffer to be sent. The flow control default setting is Enable.

Port Trunk Groups

The Switch supports the use of port trunk groups. Each trunk group may contain 2 to 4 ports as

members for a potential bit rate of up to 800 Mbps per trunk group. See the discussion of Port

Trunk Groups in Chapter 6 for more detailed information about port trunk groups.

Port Mirroring

Allows you to select a port to monitor activity for analysis. The monitored port will mirror all

activity to that port. This feature is useful for analyzing traffic in ports where acute traffic

congestion or other problems may exist.

Priority Queues

This feature allows you to customize packet traffic handling to the particular needs of your network.

Configure this setting for packets passing through the port, using IEEE 802.1p priority tagging.

These settings are universal, that is, they are for all ports on the Switch. Four priority levels may be

assigned with Queue 3 being the highest priority queue, and Queue 0 being the lowest priority queue.

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.

The highest priority queue, Queue 3, should reserved for data in which latency can have adverse

affects on the function of an application, such as video or audio data, where latency can produce

distorted sounds and images. Packets in the lower priority queues will be processed with less

urgency. See the discussion on IEEE 802.1p Priority and management of priority queues in

Chapter 6.

Figure 5-2 shows how priority queues might be assigned. Access the Priority Queue settings on the

third page of the console management screen