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Link Aggregation

Link aggregation combines multiple physical interfaces into a single aggregated (or, logical) interface, providing increased bandwidth as well as link redundancy. Traffic is distributed evenly over the physical links of the aggregation group; and, if one of the links in the aggregated interface becomes unavailable, traffic will continue to flow over the available interfaces in the group.

Link Aggregation Protocol (LACP)

LACP is a protocol used between network devices to automatically bundle links between the devices, and is supported by link aggregation. Once you configure an aggregated interface with LACP enabled, LACP packets are broadcast to other directly connected devices (such as switches and routers), which will create the necessary aggregated links (if they are also enabled for LACP).

Aggregated links on other network devices must be manually created on those devices if either LACP is disabled on the aggregated interface you create, or if a network device does not support LACP.

LACP supports active mode only; passive mode LACP is not supported.

General Process for Creating Aggregated Interfaces

1. Configuration of aggregated interfaces via the CLI/GUI by specifying:
   
   
   1. A unique aggregated interface name.
   2. The physical interfaces (ports) to be configured as members of the aggregated interface.
   3. A flag indicating whether LACP is to be enabled or disabled (it is enabled by default).

2. Assign the aggregated interface to a VLAN by adding an interface instance of the aggregation group to the VLAN

Limitations

1. A maximum of 4 physical interfaces may be combined into one aggregated interface.

2. A physical interface may belong to no more than 1 aggregated interface.

3. An aggregated interface may be specified as an untagged interface in no more than one VLAN. (There are no limitations for aggregated interfaces used as tagged interfaces; in other words, an aggregated interface may be specified as a tagged interface in multiple VLANs).

4. When assigning interfaces (physical or aggregated) to a VLAN, only one interface (physical or aggregated) can be assigned to a VLAN. In other words, if you want to assign two physical interfaces to the same VLAN, you must first create an aggregated interface containing those two physical interfaces, and then assign the aggregated interface to the VLAN.

Configuring Link Aggregation using the CLI

To create a link aggregation group and assign it to a VLAN using the CLI, do the following:

1. Create an aggregation group as follows.

eqcli > agr agr00

2. Specify the physical interfaces to be added to the aggregation group:

eqcli > agr agr00 ifi ge01,ge02

In the command line above, agr00 is the name assigned to the aggregation group; ge01 and ge01 are the physical interfaces (front panel ports) assigned as interfaces instances (ifi) to the group.

3. Verify the aggregation configuration by entering:

eqcli > show agr agr00   AGR Name   : agr00 Flags      : lacp Interfaces   :   eqcli >

Note - The LACP flag is enabled by default.

4. If you have not done so already, create a VLAN and do not assign any interfaces to it. See Configuring VLANs for how to create a VLAN.

5. Add an instance of the new link aggregation group created above. In the example below, an interface instance of the agr00 aggregated link created above is added to the VLAN vl00 as a tagged interface.

eqcli > vlan vl00 ifi agr00 type tagged

6. Verify the new VLAN configuration and associated interfaces by entering:

eqcli > show vlan v100   VLAN Name    : v100 VID          : 1 MTU          : 1500 Subnets      : sn02 Interfaces   : agr00

Removing an Aggregated Interface from a VLAN using the CLI:

eqcli > no vlan vl00 ifi agrname

Removing an Aggregated Interface from the System using the CLI:

eqcli > no agr agrname

Configuring Link Aggregation using the GUI:

To create a link aggregation group and assign it to a VLAN using the GUI, do the following:

1. Click on the System configuration tab on the left pane of the GUI if it is not already selected.
2. Click on the arrow (u) beside Network to expand the branch.
3. Click on Aggregation to display the Aggregation configuration screen. The screen features accordian tabs that will display the configured Aggregated Interfaces when clicked. The example below shows E670LX/E970LX.

4. Click on on the Aggregated Interfaces configuration screen. The Add Aggregated Interfaces dialogue shown below will be displayed. (E670LX/E970LX shown)

5. Enter a name in the Aggregated Interface Name field and select the assigned radio button on ports to be included in the aggregated interface.

Note - The Link Aggregation Control Protocol (LACP) flag is enabled by default.

6. Click on Commit to save the new aggregated interface.
7. Click on a VLAN on the left navigational pane and the aggregated interfaces that have been created will be displayed as shown below on the VLAN Configuration screen. Add Aggregated interfaces to the VLAN by selecting radio buttons . VLANs can either be tagged or untagged. tagged ports can be assigned to more than one VLAN. untagged interfaces can be assigned to exactly one VLAN. Select an appropriate radio button in Type. (E670LX/E970LX shown)

8. Click on Commit to save assignments.

Removing an Aggregated Interface from a VLAN using the GUI:

To remove an aggregated interface from a VLAN:

1. Select a VLAN from the left navigational pane to display the VLAN Configuration screen.
2. Select the unassigned radio button from the Aggregated Interfaces pane at the bottom of the screen.
3. Click on Commit to complete the process.

Removing an Aggregated Interface from the system using the GUI:

1. Click on the System configuration tab on the left pane of the GUI if it is not already selected.
2. Click on the arrow (u) beside Network to expand the branch.
3. Click on Aggregation to display the Aggregated Interfaces screen.
4. Select the Aggregated Interfaces accordian tab that you want to remove from the system.
5. Click on to remove the interface.
6. Click on Commit to complete the process.