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Introduction to Oracle Solaris 11 Networking     Oracle Solaris 11.1 Information Library
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1.  Networking on Oracle Solaris 11 Systems

Network Configuration Profiles

Reactive Network Configuration

Fixed Network Configuration

System-Generated Profiles

Network Stack in Oracle Solaris

Previous Oracle Solaris Releases

Oracle Solaris 11 Implementation

Network Devices and Datalink Names

Default Generic Link Names

Assignment of Generic Names to Datalinks

Customizing How Generic Link Names Are Assigned By the Operating System

Link Names on Upgraded Systems

Replacing Hardware-Based Link Names

Caution About Changing Link Names

Rules for Valid Link Names


Network Devices and Datalink Names

From an administrative perspective, administrators create IP interfaces on top of datalinks. The datalink represents a link object in the second layer of the Open Systems Interconnection (OSI) model. The physical link is directly associated with a device and possesses a device name. The device name is essentially the device instance name, which contains the driver name and the device instance number. The instance number can have a value from zero to n-1, depending on how many NICs use that driver on the system.

For example, consider a Gigabit Ethernet card, which is often used as the primary NIC on both host systems and server systems. Some typical driver names for this NIC are bge and e1000g. When used as the primary NIC, the Gigabit Ethernet interface has a device name such as bge0 or e1000g0. Other driver names are nge, nxge, and so on.

In this Oracle Solaris release, the device instance name continues to depend on the underlying hardware. However, as a consequence of the separation between hardware and software layers, datalinks on top of these devices are not similarly bound. Thus these datalinks can be given names other than the device names on which they are configured.

Default Generic Link Names

In Oracle Solaris 11, datalinks are automatically provided with generic names by default. This name assignment uses the net# naming convention, where # is the instance number. This instance number increments for each device, for example, net0, net1, net2, and so on.

Generic or flexible link names provide advantages in network configuration, as shown in the following examples:

To display the mapping between the datalinks with their generic names and the corresponding device instances, you use the dladm show-phys subcommand. For example:

# dladm show-phys
net2     Ethernet     up        1000      full       bge2
net0     Ethernet     up        1000      full       e1000g0
net3     Ethernet     up        1000      full       nge3
net1     Ethernet     up        1000      full       e1000g1

Assignment of Generic Names to Datalinks

In Oracle Solaris, the OS provides the generic names for all the datalinks based on specific criteria. All devices share the same prefix net. However, the instance numbers are assigned based on the following:

Based on the criteria, Ethernet devices on a lower motherboard or IO board, host bridge, PCIe root complex, bus, device, and function are ranked ahead of the other devices.

To display the correspondences of link names, devices, and locations, use the dladm show-phys command, as follows:

# dladm show-phys -L
net0         e1000g0       MB
net1         e1000g1       MB
net2         e1000g2       MB
net3         e1000g3       MB
net4         ibp0          MB/RISER0/PCIE0/PORT1
net5         ibp1          MB/RISER0/PCIE0/PORT2
net6         eoib2         MB/RISER0/PCIE0/PORT1/cloud-nm2gw-2/1A-ETH-2
net7         eoib4         MB/RISER0/PCIE0/PORT2/cloud-nm2gw-2/1A-ETH-2

Customizing How Generic Link Names Are Assigned By the Operating System

Oracle Solaris uses the prefix net when assigning link names. However, any custom prefix can be used instead, such as eth. If you prefer, you can also disable the automatic assignment of neutral link names.


Caution - You must customize how generic link names are automatically assigned before you install Oracle Solaris. After installation, you cannot customize the default link names without removing existing configurations.

To disable automatic link naming, or to customize the prefix of link names, set the following property in the System Configuration (SC) manifests. The SC manifests are used by the Automated Installer (AI) feature of Oracle Solaris.

<service name="network/datalink-management"
   version="1" type="service">
      <instance name="default enabled="true">
         <property_group name='linkname-policy'
               <propval name='phys-prefix' type='astring'

By default, the value for phys-prefix is set to net, as shown in bold.

If the value that is provided to phys-prefix is invalid, then that value is ignored. The datalinks are then named according to their associated hardware drivers, such as bge0, e1000g0, and so on. For rules about valid link names, see Rules for Valid Link Names.

Link Names on Upgraded Systems

On systems where the Oracle Solaris 11 release is freshly installed, datalinks are automatically named net0 through netN-1, where N represents the total number of network devices.

On the contrary, if you upgrade from Oracle Solaris 11 Express, the datalinks retain their names that were established prior to the upgrade. These names are either be the default hardware-based names or customized names that the administrator assigned to the datalinks before the upgrade. Further, on these upgraded systems, new network devices that are subsequently added also retain the default hardware-based names rather than receive generic names. This behavior for upgraded systems ensures that no generic names assigned by the OS become mixed with other hardware-based names or customized names assigned by the administrator before the upgrade.

On any system with Oracle Solaris 11, both hardware-based names as well as OS-supplied link names can be replaced by other names that you prefer to use. Typically, the default link names that are assigned by the OS suffice for creating the system's network configuration. However, to change link names, note the important considerations discussed in the following sections.

Replacing Hardware-Based Link Names

If your system's links have hardware-based names, rename these links with at least generic names. If you retain the hardware-based names, confusion might arise later when these physical devices are removed or replaced.

For example, you retain the link name bge0 that is associated with the device bge0. All link configurations are performed by referring to the link name. Later, you might replace the NIC bge with the NIC e1000g. To reapply the former device's link configuration to the new NIC e1000g0, you would need to reassign the link name bge0 to e1000g0. The combination of a hardware-based link name bge0 with a different associated NIC e1000g0 can cause confusion. By using names that are not hardware-based, you can better distinguish the links from the associated devices.

Caution About Changing Link Names

Although replacing hardware-based link names is a best practice, you must still plan carefully before you rename links. Changing a device's link name does not automatically propagate the new name to all existing associated configurations. The following examples illustrate the risks when you change link names:

Thus, as a general rule, do not rename datalinks randomly. When renaming datalinks, ensure that all of the link's associated configurations continue to apply after the link name is changed. Some of the configurations that might be affected by renaming links are as follows:

Rules for Valid Link Names

When you assign link names, observe the following rules:

Note - As an added restriction, you cannot use lo0 as a flexible link name. This name is reserved to identify the IP loopback interface.

The function of the link within your network setup can be a useful reference when you assign link names. For example, netmgt0 can be a link that is dedicated to network management. Upstream2 can be the link that connects to the ISP. As a general rule to avoid confusion, do not assign names of known devices to your links.