IBM ATM OC-3c Virtual LAN Concepts, What is a Virtual LAN VLAN?, Creating Inter-switch VLANs

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VIRTUAL LAN CONCEPTS

This chapter provides a brief overview of

Virtual LAN (VLAN) concepts, and describes how to extend VLANs into the ATM network.

This user guide does not describe how to create or configure VLANs. VLAN configuration is described in the user guide that accompanies your Switch.

What is a Virtual LAN (VLAN)?

A Virtual LAN (VLAN) is a flexible, location and topology independent group of end-stations communicating as if they are on a common physical LAN.

You can create VLANs that closely correspond to how your network and business functions. For example, marketing personnel in different physical locations could be part of one VLAN and finance personnel could be in another VLAN.

VLANs provide the following benefits:

■VLANs make moves and changes simple.

■As each VLAN is a common broadcast domain, you can erect firewalls against broadcast storms.

■VLANs improve security.

For a full description of VLAN functionality, refer to the user guide that accompanies your Switch.

Creating Inter-switch VLANs

You can create inter-switch VLANs using Virtual LAN Trunks (VLTs) on Fast Ethernet connections, as shown in Figure 3-1.

Figure 3-1Inter-switch VLANs