Cabletron Systems 802.1Q manual Data frame that does not have a Tag Header

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VLAN Terms

The configuration is accomplished using the Local Management VLAN Forwarding Configuration screen. By default a VLAN is assigned to the FID that matches its VLAN ID.

Tag Header (VLAN Tag)

Four bytes of data inserted in a frame that identifies the VLAN/frame classification. The Tag Header is inserted into the frame directly after the Source MAC address field. Twelve bits of the Tag Header represent the VLAN ID. The remaining bits are other control information.

Tagged Frame

A data frame that contains a Tag Header. A VLAN aware device can add the Tag Header to any frame it transmits.

Untagged Frame

A data frame that does not have a Tag Header.

Default VLAN

The VLAN to which all ports are assigned upon initialization. The Default VLAN has a VLAN ID of 1 and cannot be deleted or renamed.

Forwarding List

A list of the ports on a particular device that are eligible to transmit frames for a selected VLAN.

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 switch makes a forwarding decision on a frame.

1Q Trunk

A connection between 802.1Q switches that passes only traffic with a VLAN Tag Header inserted in the frame. By default, a port designated as a 1Q Trunk port has all VLANs in its Port VLAN List and is configured to transmit all frames as tagged frames. A 1Q Trunk drops all incoming frames that do not have a VLAN tag.

802.1Q VLAN User’s Guide

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Contents 802.1Q Vlan User’s Guide Page 802.1Q Vlan User’s Guide 802.1Q Vlan User’s Guide Contents Contents Contents Contents 802.1Q Vlan User’s Guide Figures Tables Structure of this Guide Using this GuideDocument Conventions Related DocumentsDefining VLANs Chapter Virtual Local Area NetworksBuilding One Building Two 1 802.1Q VLANs Types of VLANsSecureFast VLANs Other Vlan StrategiesVlan Terms Benefits and RestrictionsData frame that does not have a Tag Header 1D Trunk Your email address Getting Help802.1Q Vlan User’s Guide Vlan Components DescriptionClassifying Frames to a Vlan Configuration Process1 Defining a Vlan Customizing the Vlan Forwarding List Vlan Switch OperationReceiving Frames from Vlan Ports Inside the SwitchKnown Unicasts Forwarding DecisionsBroadcasts, Multicasts, and Unknown Unicasts Garp Switch Operation Switch Without VLANs Managing the SwitchSwitch Management with VLANs Switch with VLANsManaging the Switch Preparing for Vlan Configuration Summary of Vlan Local ManagementWhen to Use 802.1Q Vlan Configuration Menu ScreenHow to Access Menu Definitions Device Vlan Configuration Screen Device Vlan Configuration ScreenField Definitions 1 Defining a Vlan Renaming a Vlan Changing the Vlan to FID AssociationDisabling VLANs Deleting a VlanEnabling VLANs Paging Through the Vlan List Changing the Forwarding ModePort Assignment Configuration Screen Port Assignment Configuration ScreenPort Mode Changing the Port ModeAssigning a Vlan ID Paging Through the Port List Port Filtering Configuration ScreenPort Filtering Configuration Screen Vlan Lists Displaying Vlan IDs Associated with a PortSelecting the Type of Filtering for a Port Vlan Forwarding Configuration Screen Vlan Forwarding Configuration ScreenFrame Format Viewing Current Vlan PortsDeleting Forwarding List Entries Paging Through Vlan Forwarding List EntriesAdding Forwarding List Entries Changing the Frame Format Protocol Vlan Configuration ScreenProtocol Vlan Configuration Screen Selectable Feature Status Ether type Assigning a Protocol Family to a Vlan IDProtocol Vlan Configuration Screen Displaying the Protocol Types on Current Ports 10 Protocol Ports Configuration Screen Protocol Ports Configuration ScreenDelete ALL Quick Vlan Walkthrough Adding/Deleting Ports Associated with a Vlan ID802.1Q Vlan User’s Guide Hybrid 12 Walkthrough Stage Two 13 Walkthrough Stage Three 14 Walkthrough Stage Four Quick Vlan Walkthrough 15 Final Walkthrough Stage Chapter Examples Example 1, Single Switch OperationSwitch Configured for VLANs Solving the ProblemFrame Handling Example 2, Vlans Across Multiple Switches Example 2, VLANs Across Multiple Switches Switch Example 2, VLANs Across Multiple Switches Bridge 1 Broadcasts Frames Transmitting to Switch Transmitting to Bridge Example 3, 1D Trunk Connection to 802.1Q Vlan NetworkExample 3, 1D Trunk Connection to 802.1Q Vlan Network Solving the Problem Frame Handling 226318 Switch 2 Forwards to 1Q Trunk Examples Example 4, Isolating Network Traffic According to Protocol 11 Example 4, Isolating Traffic According to Protocol Switch Examples Example 4, Isolating Network Traffic According to Protocol Examples 802.1Q Vlan User’s Guide Numerics IndexIndex-2 802.1Q Vlan User’s Guide 802.1Q Vlan User’s Guide Index-3 Index Index-4 802.1Q Vlan User’s Guide