Summary of the content on the page No. 1
802.1Q VLAN
User’s Guide
9032599-03
Summary of the content on the page No. 2
Summary of the content on the page No. 3
NOTICE Enterasys Networks reserves the right to make changes in specifications and other information contained in this document and its web site without prior notice. The reader should in all cases consult Enterasys Networks to determine whether any such changes have been made. The hardware, firmware, or software described in this document is subject to change without notice. IN NO EVENT SHALL ENTERASYS NETWORKS BE LIABLE FOR ANY INCIDENTAL, INDIRECT, SPECIAL, OR CONSEQUENTIAL DAMAGES WHATSOE
Summary of the content on the page No. 4
Summary of the content on the page No. 5
Contents Figures ............................................................................................................................................ v Tables..............................................................................................................................................vi PREFACE Using This Guide............................................................................................................vii Structure of This Guide .............................
Summary of the content on the page No. 6
3.4.1 Defining a VLAN ...........................................................................3-10 3.4.2 Changing the VLAN to FID Association........................................3-11 3.4.3 Renaming a VLAN ........................................................................3-11 3.4.4 Deleting a VLAN ...........................................................................3-12 3.4.5 Enabling VLANs............................................................................3-12 3.4.6 Dis
Summary of the content on the page No. 7
Figures Figure Page 1-1 Example of a VLAN .........................................................................................................1-2 2-1 Inside the Switch .............................................................................................................2-3 3-1 Switch Management with Only Default VLAN .................................................................3-2 3-2 Switch Management with VLANs ...................................................................
Summary of the content on the page No. 8
Tables Table Page 3-1 802.1Q VLAN Configuration Menu Screen Menu Items ...............................................3-6 3-2 Device VLAN Configuration Screen Field Definitions ...................................................3-9 3-3 Port Assignment Configuration Screen Field Definitions ............................................3-15 3-4 Port Filtering Configuration Screen Field Definitions ..................................................3-18 3-5 VLAN Forwarding Configuration Screen Field
Summary of the content on the page No. 9
Preface Welcome to the Enterasys Networks 802.1Q VLAN User’s Guide. This guide introduces and describes Enterasys Networks’ implementation of the IEEE 802.1Q standard for 802.1Q Virtual Local Area Network (VLAN) technology, and the VLAN Local Management screens used to configure Enterasys Networks products used in 802.1Q VLAN environments. IMPORTANT NOTICE Information in this guide refers to firmware version 3.x and 4.x only. It does not refer to firmware version 5.x. This guide applies to 2
Summary of the content on the page No. 10
Related Documents Chapter 3, VLAN Configuration, describes how to set up the switch for local and remote management, shows the Local Management screens used in 802.1Q VLAN configuration and explains their use. Chapter 4, Examples, offers examples of 802.1Q VLANs and explains how network transmissions are treated by the components of each VLAN. RELATED DOCUMENTS Other Enterasys Networks documents that may be useful for understanding some of the concepts introduced or discussed in this guide
Summary of the content on the page No. 11
1 Virtual Local Area Networks This chapter introduces the concepts of Virtual Local Area Networks (VLANs) and discusses the central concepts of IEEE 802.1Q VLANs. This chapter also contains information on how to contact Enterasys Networks for additional support related to VLANs. 1.1 DEFINING VLANs A Virtual Local Area Network is a group of devices that function as a single Local Area Network segment (broadcast domain). The devices that make up a particular VLAN may be widely separated, both
Summary of the content on the page No. 12
Types of VLANs
! "# !$ # Figure 1-1 Example of a VLAN In this example, the Sales and Finance workstations have been placed on two separate VLANs. In a plain Ethernet environment, the entire network is a broadcast domain, and the SmartSwitches follow the IEEE 802.1D bridging specification to send data between stations. A broadcast or multicast transmissio
Summary of the content on the page No. 13
Benefits and Restrictions 1.2.1 802.1Q VLANs An 802.1Q VLAN switch determines the VLAN membership of a data frame by its Tag Header, described later in this chapter. If the frame received is not tagged, the switch classifies the frame into the VLAN that is assigned as the default VLAN of the switch. Some or all ports on the switch may be configured to operate as GARP VLAN Registration Protocol (GVRP) ports. If a frame received is tagged, the frame is forwarded to the GVRP ports that are con
Summary of the content on the page No. 14
VLAN Terms 1.4 VLAN TERMS To fully understand the operation and configuration of port based VLANs, it is essential to understand the definitions of several key terms. VLAN ID A unique number (between 1 and 4094) that identifies a particular VLAN. VLAN Name A 32-character alphanumeric name associated with a VLAN ID. The VLAN Name is intended to make user-defined VLANs easier to identify and remember. Filtering Database Identifier (FID) Addressing information that the device learns about a VLA
Summary of the content on the page No. 15
VLAN Terms Port VLAN List A per port list of all eligible VLANs whose frames can be forwarded out one specific port and the frame format (tagged or untagged) of transmissions for that port. The Port VLAN List specifies what VLANs are associated with a single port for frame transmission purposes. Filtering Database A database structure within the switch that keeps track of the associations between MAC addresses, VLANs, and interface (port) numbers. The Filtering Database is referred to when a
Summary of the content on the page No. 16
Getting Help 1.5 GETTING HELP For additional support related to this document, contact Enterasys Networks using one of the following methods: World Wide Web http://www.enterasys.com Phone (603) 332-9400 Internet mail support@enterasys.com FTP ftp://ftp.enterasys.com Login anonymous Password your email address To send comments or suggestions concerning this document, contact the Technical Writing Department via the following email address: TechWriting@enterasys.com Make sure to include the docu
Summary of the content on the page No. 17
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 V
Summary of the content on the page No. 18
Configuration Process 2.3 CONFIGURATION PROCESS Before a VLAN can operate, steps must be performed to configure the switch to establish and configure a VLAN. Enterasys Networks VLAN aware SmartSwitches default to operate in the 802.1Q VLAN mode. However, further configuration is necessary to establish multiple logical networks. NOTE: The actual steps involved in VLAN configuration using Local Management are presented in Chapter 3, VLAN Configuration.This brief section describes the actions
Summary of the content on the page No. 19
VLAN Switch Operation 2.4 VLAN SWITCH OPERATION IEEE 802.1Q VLAN switches act on the classification of frames into VLANs. Sometimes, VLAN classification is based on tags in the headers of data frames. These VLAN tags are added to data frames by the switch as the frames are transmitted out certain ports, and are later used to make forwarding decisions by the switch and other VLAN aware switches. In the absence of a VLAN tag header, the classification of a frame into a particular VLAN depends
Summary of the content on the page No. 20
VLAN Switch Operation 2.4.1 Receiving Frames from VLAN Ports When a switch is placed in 802.1Q Operational Mode, every frame received by the switch must belong, or be assigned, to a VLAN. Untagged Frames The switch receives a frame from Port 1 and examines the frame. The switch notices that this frame does not currently have a VLAN tag. The switch recognizes that Port 1 is a member of VLAN A and classifies the frame as such. In this fashion, all untagged frames entering a VLAN switch assume
