| Sun 10-Gigabit Ethernet PCI-X Adapter Installation and User’s Guide |    
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| C H A P T E R 4 |
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Configuring VLANs |
This chapter explains Virtual Local Area Networks (VLANs) in detail and provides configuration instructions and examples. It contains the following sections:
With multiple VLANs on an adapter, a server with a single adapter can have a logical presence on multiple IP subnets. By default, 128 VLANs can be defined for each VLAN-aware adapter on your server. However, this number can be increased by changing the system parameters.
If your network does not require multiple VLANs, you can use the default configuration, in which case no further configuration is necessary.
VLANs enable you to split your physical LAN into logical subparts, providing an essential tool for increasing the efficiency and flexibility of your network.
VLANs are commonly used to separate groups of network users into manageable broadcast domains, to create logical segmentation of workgroups, and to enforce security policies among each logical segment. Each defined VLAN behaves as its own separate network, with its traffic and broadcasts isolated from the others, increasing the bandwidth efficiency within each logical group.
Although VLANs are commonly used to create individual broadcast domains and/or separate IP subnets, it can be useful for a server to have a presence on more than one VLAN simultaneously. Several Sun products support multiple VLANs on a per port or per interface basis, allowing very flexible network configurations.
FIGURE 4-1 shows an example network that uses VLANs.
FIGURE 4-1 Example of Servers Supporting Multiple VLANs With Tagging Adapters
The example network has the following features:
The physical LAN network consists of a switch, two servers, and five clients. The LAN is logically organized into three different VLANs, each representing a different IP subnet.
The Main Server is a high-use server that needs to be accessed from all VLANs and IP subnets. The server has a Sun 10-Gigabit Ethernet adapter installed. All three IP subnets are accessed by means of the single physical adapter interface. The server is attached to one of the switch’s Gigabit Ethernet ports, which is configured for VLANs 1, 2, and 3. Both the adapter and the connected switch port have tagging turned on. Because of the tagging VLAN capabilities of both devices, the sever is able to communicate on all three IP subnets in this network, but continues to maintain broadcast separation between all of them. The following list describes the components of this network:
VLAN tagging is only required to be enabled on switch ports that create trunk links to other VLAN-aware Ethernet switches, or on ports connected to tag-capable end-stations, such as servers or workstations with VLAN-aware adapters.
VLANs can be created according to various criteria, but each VLAN must be assigned a VLAN tag or VLAN ID (VID). The VID is a 12-bit identifier between 1 and 4094 that identifies a unique VLAN. For each network interface (ixge0, ixge1, ixge2 and so on), 4094 possible VLAN IDs can be selected. Only 512 unique IDs can be used simultaneously. Because IP subnets are commonly used, it is best to use IP subnets when setting up a VLAN network interface. This means that each VID assigned to a VLAN interface of a physical network interface will belong to different subnets.
Tagging an Ethernet frame requires the addition of a tag header to the frame. The header is inserted immediately following the destination MAC address and the Source MAC address. The tag header consists of two bytes of Ethernet Tag Protocol identifier (TPID, 0x8100) and two bytes of Tag Control Information (TCI). FIGURE 4-2 shows the Ethernet Tag Header format.
FIGURE 4-2 Ethernet Tag Header Format
By default, a single VLAN is configured for every port, which groups all ports into the same broadcast domain, just as if there were no VLANs at all, VLAN tagging for the switch port turned off.
| Note - If you configure a VLAN virtual device for an adapter, all traffic sent or received by that adapter must be in VLAN-tagged format. |
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1. Create one hostname6.ixgenumber file for each VLAN that will be configured for each adapter on the server.
Use the following naming format, which includes both the VID and the physical point of attachment (PPA):
VLAN logical PPA = 1000 * VID + Device PPA
ixge123000 = 1000*123 + ixge
This format limits the maximum number of PPAs (instances) you can configure to 1000 in the /etc/path_to_inst file.
For example, on a server with the Sun 10-Gigabit Ethernet adapter having an instance of 0, belonging to a member of two VLANs, with VID 123 and 224, you would use ixge123000 and ixge224000, respectively, as the two VLAN PPAs.
2. Use the ifconfig(1M) to configure a VLAN virtual device, for example:
The output of ifconfig -a on a system having VLAN devices ixge123000 and ixge224000:
3. On the switch, set VLAN tagging and set VLAN ports to coincide with the VLANs you’ve set up on the server.
Using the examples in Step 2, you would set up VLAN ports 123 and 224 on the switch.
Refer to the documentation that came with your switch for specific instructions for setting VLAN tagging and ports.
| Sun 10-Gigabit Ethernet PCI-X Adapter Installation and User’s Guide | 819-0938-13 |
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Copyright © 2008 Sun Microsystems, Inc. All Rights Reserved.
To Configure Static VLANs