Q-Logic 8100 SERIES manual Vlan Configuration, Vlan Prerequisites

6–Configuring NIC Functionality in the Converged Network Adapter Configuring the NIC in a Linux Environment

VLAN Configuration

A virtual LAN (VLAN) is a logical grouping of network hosts connected to a switch to achieve a logical segmentation of a physical network. By default, all switches make up a broadcast domain in the layer-2 switched network. Creating a VLAN breaks up a broadcast domain into smaller domains within a switch by assigning different ports to different subnets. The benefits of using VLANs include broadcast control, security, flexibility, and scalability.

VLAN configuration assigns a VLAN ID to a NIC interface. The protocol most commonly used to configure VLANs is Virtual LANs IEEE 802.1Q. Using this protocol, the QLogic adapter NIC function assigns a VLAN ID to each frame that it transmits. The connected switch interprets the tag, and packets are switched only within the VLAN. Communication across VLANs requires a layer-3 router.

NOTE:

The VLAN ID is set for the entire team and not for individual ports in the team.

VLAN Prerequisites

The following software components are required to configure VLANs on Linux systems with network interface bonding.

VLAN 802.1q kernel module (8021q)—Linux kernel module that provides the VLAN 802.1q support for network interfaces. The Linux 8021q VLAN driver creates VLANs on Linux network interfaces over both physical and bonded interfaces. The VLAN 802.1q driver is a kernel-loadable module (8021q.ko) that resides in the

/lib/modules/2.6.18-164.el5/kernel/net/8021q/ directory on RHEL 5-based distributions.

vconfig utility—A user-level control program for managing VLANs in Linux. vconfig is a VLAN (802.1q) configuration program that creates and removes VLAN devices on a VLAN-enabled kernel (such asRHEL 5). VLAN devices are virtual Ethernet devices that represent the VLANs on the physical LAN. For information about the vconfig command, enter the man vconfig command to display the manual page.

The VLAN 802.1q kernel module and the vconfig utility are available by default in all RHEL 5 installations.

NOTE:

To enable all VLAN capabilities in Linux, you must configure VLANs on the attached Ethernet switch. For information about configuring VLANs on the switch, refer to the Ethernet switch vendor documentation.

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