Enterasys Networks 802.1Q VLAN Operation

VLAN Operation 2-1

2

VLAN Operation

This chapter describes the operation of a VLAN switch and discusses the operations that a VLAN

switch performs in response to both normal and VLAN-originated network traffic.

2.1 DESCRIPTION

The 802.1Q VLAN operation is slightly different than the operation of traditional switched

networking systems. These differences are due to the importance of keeping track of each frame

and its VLAN association as it passes from switch to switch or from port to port within a switch.

2.2 VLAN COMPONENTS

Before describing the operation of an 802.1Q VLAN, it is important to understand the basic

elements that are combined to make up an 802.1Q VLAN.

Stations

A station is any end unit that belongs to a network. In the vast majority of cases, stations are the

computers through which the users access the network.

Switches

In order to configure a group of stations into a VLAN, the stations must be connected to VLAN

aware switches. It is the job of the switch to classify received frames into VLAN memberships and

transmit frames, according to VLAN membership, with or without a VLAN Tag Header.

Contents

Main Page NOTICE Page Contents PREFACE 1 2 3 4 Figures Tab le s Preface USING THIS GUIDE STRUCTURE OF THIS GUIDE IMPORTANT NOTICE RELATED DOCUMENTS DOCUMENT CONVENTIONS Virtual Local Area Networks 1.1 DEFININ G VLANs A B 1.2 TYPES OF VLANs 1.2.1 802.1Q VLANs 1.2.2 SecureFast VLANs 1.2.3 Other VLAN Strategies 1.3 BENEFITS AND RESTRICTIONS 1.4 VLAN TERMS Page 1.5 GETTING HELP VLAN Operation 2.1 DESCRIPTION 2.2 VLAN COMPONENTS 2.3 CONFIGURATION PROCESS 2.3.1 Defining a VLAN 2.3.2 Classifying Frames to a VLAN 2.3.3 Customizing the VLAN Forwarding List 2.4 VLAN SWITCH OPERATION 2.4.1 Receiving Frames from VLAN Ports 2.4.2 Forwarding Decisions 2.4.2.1 Broadcasts, Multicasts, and Unknown Unicasts 2.4.2.2 Known Unicasts 2.5 GARP SWITCH OPERATION Page VLAN Configuration 3.1 MANAGING THE SWITCH 3.1.1 Switch Without VLANs Page 1 3 6 2 7 4 5 802.1Q Switch 3.2 SUMMARY OF VLAN LOCAL MANAGEMENT 3.3 802.1Q VLAN CONFIGURATION MENU SCREEN Menu Definitions 3.4 DEVICE VLAN CONFIGURATION SCREEN Device VLAN Configuration Screen 3-8 VLAN Configuration Figure 3-5 Device VLAN Configuration Screen Page 3.4.1 Defining a VLAN 3.4.2 Changing the VLAN to FID Association 3.4.3 Renaming a VLAN 3.4.4 Deleting a VLAN 3.4.5 Enabling VLANs 3.4.6 Disabling VLANs 3.4.7 Changing the Forwarding Mode 3.4.8 Paging Through the VLAN List Port Assignment Configuration Screen 3-14 VLAN Configuration 3.5 PORT ASSIGNMENT CONFIGURATION SCREEN Figure 3-6 Port Assignment Configuration Screen 3.5.1 Changing the Port Mode 3.5.2 Assigning a VLAN ID 3.5.3 Paging Through the Port List 3.6 PORT FILTERING CONFIGURATION SCREEN Page 3.6.1 Displaying VLAN IDs Associated with a Port 3.6.2 Selecting the Type of Filtering for a Port 3.7 VLAN FORWARDING CONFIGURATION SCREEN Page 3.7.1 Viewing Current VLAN Ports 3.7.2 Paging Through VLAN Forwarding List Entries 3.7.3 Adding Forwarding List Entries 3.7.4 Deleting Forwarding List Entries 3.7.5 Changing the Frame Format 3.8 PROTOCOL VLAN CONFIGURATION SCREEN Page Page 3.8.1 Displaying the Current Protocol, VLAN ID, and Port Assignments 3.8.2 Assigning a Protocol Family to a VLAN ID Page 3.8.3 Displaying the Protocol Types on Current Ports 3.9 PROTOCOL PORTS CONFIGURATION SCREEN Page 3.9.1 Adding/Deleting Ports Associated with a VLAN ID 3.10 QUICK VLAN WALKTHROUGH Page Quick VLAN Walkthrough 3-34 VLAN Configuration Figure 3-12 Walkthrough Stage Two NOTE: For the purposes of this walkthrough, port 10 will be configured as the trunk port. Quick VLAN Walkthrough VLAN Configuration 3-35 Figure 3-13 Walkthrough Stage Three Page Page Page Examples 4.1.1 Solving the Problem 3 6 B1 2 4 5 4.1.2 Frame Handling 4.2 EXAMPLE 2, VLANs ACROSS MULTIPLE SWITCHES Example 2, VLANs Across Multiple Switches 4-4 Examples Figure 4-3 Example 2, VLANs Across Multiple Switches 4.2.1 Solving the Problem Page 4.2.2 Frame Handling Page 4.3 EXAMPLE 3, 1D TRUNK CONNECTION TO 802.1Q VLAN NETWORK Example 3, 1D Trunk Connection to 802.1Q VLAN Network Examples 4-9 Figure 4-7 Example 3, 1D Trunk Connection to 802.1Q VLAN Network 4.3.1 Solving the Problem 4.3.2 Frame Handling Page Page 4.4 EXAMPLE 4, ISOLATING NETWORK TRAFFIC ACCORDING TO PROTOCOL Example 4, Isolating Network Traffic According to Protocol Examples 4-15 Figure 4-11 Example 4, Isolating Traffic According to Protocol 4.4.1 Solving the Problem Page Page Index Numerics C D E N O P R S