How to Change Link Speed Parameters

Most network setups consist of a combination of systems with varying speed capabilities. For example, the advertised speed between an older system and a newer system might need to be changed to a lower setting to allow communication. By default, all the speed and duplex capabilities of a NIC card are advertised. This procedure shows how to turn off the gigabit capabilities and advertise only the megabit capabilities.

1. On the system that has the NIC whose properties you want to modify, assume the System Administrator role.

   The System Administrator role includes the Network Management profile. To create the role and assign the role to a user, see Chapter 9, Using Role-Based Access Control (Tasks), in System Administration Guide: Security Services.

2. (Optional) Display the current status of the property you want to modify.

   # dladm show-linkprop -p property data-link

3. To advertise lower speed capabilities, turn off the higher speed capabilities to prevent them from being advertised.

   # dladm set-linkprop -p property=value1 data-link

Example 1–2 Disabling Advertisement of a NIC's Gigabit Capabilities

This example shows how you can prevent the link web1 from advertising gigabit capabilities.

# dladm show-linkprop -p adv_1000fdx_cap web1
LINK     PROPERTY             VALUE     DEFAULT     POSSIBLE
web1     adv_1000fdx_cap      1         --          1,0

# dladm show-linkprop -p adv_1000hdx_cap web1
LINK     PROPERTY             VALUE     DEFAULT     POSSIBLE
web1     adv_1000hdx_cap      1         --          1,0

The properties that advertise the link's gigabit capabilities are adv_1000fdx_cap and adv_1000hdx_cap. To disable these properties from being advertised, you would type the following commands:

# dladm set-linkprop -p adv_1000fdx_cap=0 web1
# dladm set-linkprop -p adv_1000hdx_cap=0 web1

Listing the Ethernet parameter settings would display the following output:

# dladm show-ether web1
LINK     PTYPE       STATE    AUTO  SPEED-DUPLEX             PAUSE
web1     current     up       yes   1G-f                     both