(Optional) Configuring an Expected Lease

Context

To enable a DHCP client to determine the lease length, configure an expected lease on the DHCP client. If the expected lease is longer than the global lease, the global lease takes effect.

Procedure

Enter the system view.
```
system-view 
```
Enter the interface view or sub-interface view.
```
interface interface-type interface-number [.subinterface-number ]
```
Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731S-H, S5731-S, S5731S-S, S6720-HI, S5732-H, S6730-H, S6730S-H, S6730-S, S6730S-S, S6720-EI, and S6720S-EI support sub-interfaces.
(Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.

By default, an Ethernet interface works in Layer 2 mode.

Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
Configure the expected lease.
```
dhcp client expected-lease time
```
By default, no expected lease is configured for a DHCP client.
Renew the lease of the DHCP client's IP address.
```
dhcp client renew
```
This command takes effect only if an IP address is already assigned.