Link Aggregation

Link aggregation is an inexpensive way to set up a high-speed backbone network that transfers much more data than any one single port or device can deliver without replacing everything and buying new hardware.

For most backbone installations, it is common to install more cabling or fiber optic pairs than initially necessary, even if there is no immediate need for the additional cabling. This action is taken because labor costs are higher than the cost of the cable and running extra cable reduces future labor costs if networking needs changes. Link aggregation can allow the use of these extra cables to increase backbone speeds with little or no extra cost if ports are available.

This Managed switch supports 2 link aggregation modes: static Port Trunk and dynamic Link Aggregation Control Protocol (LACP) using the IEEE 802.3ad standard. These allow several devices to communicate simultaneously at their full single-port speed while not allowing any one single device to occupy all available backbone capacities.

Click Link Aggregation folder from the Switch Management menu and then three options within this folder will be displayed.

1. Trunk Mode Configuration: Enable or disable Source and Destination MAC address.

2. Port Trunk Configuration: Create, edit or delete port trunking group(s).

3. LACP Port Configuration: Set up the configuration of LACP on all or some ports.

4.4.3.1 Trunk Mode Configuration

Click the option Trunk Mode Configuration from the Link Aggregation menu and then the following screen page appears.

There are two fields for you to set up packets according to operations.

Source MAC Address: Enable or disable packets according to source MAC address.

Destination MAC Address: Enable or disable packets according to Destination MAC address.

4.4.3.2 Port Trunk Configuration

Click the option Port Trunk Configuration from the Link Aggregation menu and then the following screen page appears.

The Managed Switch allows users to create 12 trunking groups. Each group consists of 2 to 16 links (ports).

Click New to add a new trunk group and then the following screen page appears.

Click Delete to remove a current registered trunking group setting.

Click Edit to view and edit a registered trunking group‟s settings.

Group Name: Specify the trunking group name of up to 15 alphanumeric characters.

Port Members: Select ports that belong to the specified trunking group. Please keep the rules below in mind when assign ports to a trunking group.

- Must have 2 to 16 ports in each trunking group.

- Each port can only be grouped in one group.

- If the port is already set On in LACP Port Configuration, it can‟t be grouped anymore.

Click OK to return back to Link Aggregation menu.

NOTE: All trunking ports in the group must be members of the same VLAN and their Spanning Tree Protocol (STP) status and QoS default priority configurations must be identical. Port locking, port mirroring and 802.1X can not be enabled on the trunk group.

Furthermore, the LACP aggregated links must all be of the same speed and should be configured as full duplex.

4.4.3.3 LACP Port Configuration

The Managed Switch supports dynamic Link Aggregation Control Protocol (LACP) which is specified in IEEE 802.3ad. Static trunks have to be manually configured at both ends of the link. In other words, LACP configured ports can automatically negotiate a trunked link with LACP configured ports on another devices. You can configure any number of ports on the Managed Switch as LACP, as long as they are not already configured as part of a static trunk. If ports on other devices are also configured as LACP, the Managed Switch and the other devices will negotiate a trunk link between them. If an LACP trunk consists of more than four ports, all other ports will be placed in a standby mode. Should one link in the trunk fail, one of the standby ports will automatically be activated to replace it.

Configure Port Protocol:

Click the option LACP Port Configuration from the Link Aggregation menu and then select “Protocol” from the pull-down menu of Select Setting. The screen page is shown below.

This allows LACP to be enabled or disabled on each port.

Configure Key Value:

Select “Key Value” from the pull-down menu of Select Setting.

Ports in an aggregated link group must have the same LACP port Key. In order to allow a port to join an aggregated group, the port Key must be set to the same value. The range of key value is between 0 and 255. When key value is set to 0, the port Key is automatically set by the Managed Switch.

Configure Port Role:

Select “Role” from the pull-down menu of Select Setting.

Active – Active LACP ports are capable of processing and sending LACP control frames.

This allows LACP compliant devices to negotiate the aggregated link so that the group may be changed dynamically as required. In order to utilize the ability to change an aggregated port group, that is, to add or remove ports from the group, at least one of the participating devices must designate LACP ports as active. Both devices must support LACP.

Passive –LACP ports that are designated as passive cannot initially send LACP control frames. In order to allow the linked port group to negotiate adjustments and make changes dynamically, one end of the connection must have “active” LACP ports.