Configuring a Layer 3 dynamic aggregation group

Prerequisites

You must be in the global configuration context: switch(config)#

Procedure

Create a Layer 3 aggregate interface and access the Layer 3 aggregate interface view by entering:
```
switch(config)# interface lag <ID>
```
The range of the LAG interface ID is 1 to 256.

While creating the Layer 3 aggregate interface, the system automatically creates a Layer 3 dynamic aggregation group numbered the same.
Set the operational state of every interface in the LAG to up by entering:
```
switch(config-lag-if)# no shutdown
```
NOTE:
This command does not impact the administrative state of the member interfaces because the command was entered at the level of the LAG. To change the administrative state of a member interface, enter the command at the interface level. For example:
```
switch(config)# interface 1/1/2
switch(config-if)# no shutdown
```

Configure the aggregation group to operate in dynamic mode by entering:

switch(config-lag-if)# lacp mode {active | passive}

For example:

switch(config-lag-if)# lacp mode active

Configure the aggregation group to operate in fast or slow mode by entering:
```
switch(config-lag-if)# lacp rate {fast | slow}
```
For example:
```
switch(config-lag-if)# lacp rate fast
```

Set the IP address on the LAG interface by entering:

switch(config-lag-if)# ip address <IPV4-ADDR>/<MASK>

For example:

switch(config-lag-if)# ip address 192.0.3.1/30

Use the following steps to add a maximum of eight interfaces to the LAG:
1. To assign an interface to the LAG:
```
switch(config-lag-if)# interface <PORT-ID>
```
  To assign a range of interfaces to a LAG:
```
switch(config-lag-if)# interface <PORT-ID>-<PORT-ID>
```
  For example:
```
switch(config-lag-if)# interface 1/1/1-1/1/4
```
  See the Command-Line Interface Guide for your switch and software version for more information about the interface <PORT-ID> command.
2. Assign an ID to the LAG:
```
switch(config-if)# lag <ID>
```
  For example:
```
switch(-<1/1/1-1/1/4>)# lag 100
```
3. Set the administrative state of the member interface to up:
```
switch(-<1/1/1-1/1/4>)# no shutdown
```

View the configuration by entering:

switch(config-if-<1/1/1-1/1/4>)# show running-config

Current configuration: 
!
vlan 1
interface lag 100
    no shutdown
    ip address 192.0.3.1/30
    lacp mode active
interface 1/1/1
    no shutdown
    lag 100
interface 1/1/2
    no shutdown
    lag 100
interface 1/1/3
    no shutdown
    lag 100
interface 1/1/4
    no shutdown
    lag 100

switch(config-if-<1/1/1-1/1/4>)# show lacp aggregates

Aggregate name   : lag100
Interfaces       : 1/1/3 1/1/1 1/1/4 1/1/2
Heartbeat rate   : Fast
Hash             : l3-src-dst
Aggregate mode   : Active