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Cabletron Systems 802.1Q manual 8 Bridge 1 Broadcasts Frames

Models: 802.1Q

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Figure 4-8 Bridge 1 Broadcasts Frames

Chapter 4: Examples

2.Switch 4 receives the frame and classifies this new untagged frame as belonging to the Red VLAN. Since the frame is a broadcast, it is forwarded to any ports that are classified as eligible to receive Red VLAN frames. Switch 4 also updates its Source Address Table for FID 1, identifying User B as being located out Port 1.

On Switch 4, the only port eligible to receive Red VLAN frames is Port 4, the 1Q Trunk. The frame is forwarded out Port 4 with the Red VLAN Tag header being added, as shown in Figure 4-8.

User B

Bridge 1		2
Bridge 1
Red VLAN	1	4 3
		4

Bridge 2

Blue VLAN

Floor 4

2263_18

Figure 4-8 Bridge 1 Broadcasts Frames

3.Switch 2 receives the tagged Red VLAN frame on Port 2, as shown in Figure 4-9. The VLAN Tag in the frame is maintained, classifying the frame as belonging to the Red VLAN. The switch forwards the broadcast frame out all the eligible ports, Ports 3 and 4. Switch 2 simultaneously updates its Source Address Table for FID 1 to reflect the location of User B (Port 2).

The frame forwarded out Port 3 has its VLAN Tag stripped before transmission, and it is passed to Bridge 4 as a normal broadcast frame. The frame that is transmitted out Port 4, the 1Q Trunk, retains its VLAN tag.

4-14	802.1Q VLAN User’s Guide

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Cabletron Systems 802.1Q manual 8 Bridge 1 Broadcasts Frames

Contents

802.1Q VLAN User’s Guide 9032599-02Page 802.1Q VLAN User’s Guide 802.1Q VLAN User’s Guide CONTENTS PREFACECHAPTER VIRTUAL LOCAL AREA NETWORKSContents VLAN CONFIGURATIONCHAPTER 802.1Q VLAN User’s GuideContents CHAPTEREXAMPLES 802.1Q VLAN User’s GuideContents 802.1Q VLAN User’s GuideFIGURES 802.1Q VLAN User’s GuideTABLES 802.1Q VLAN Configuration Menu Screen Menu Items802.1Q VLAN User’s Guide viiiSTRUCTURE OF THIS GUIDE USING THIS GUIDEPREFACE RELATED DOCUMENTS DOCUMENT CONVENTIONSCHAPTER VIRTUAL LOCAL AREA NETWORKS 1.1 DEFINING VLANsBuilding One Building Two1.2 TYPES OF VLANs 1.2.1 802.1Q VLANs1.2.2 SecureFast VLANs 1.2.3 Other VLAN Strategies1.3 BENEFITS AND RESTRICTIONS 1.4 VLAN TERMSA data frame that does not have a Tag Header 1D Trunk Generic Attribute Registration Protocol GARPGARP VLAN Registration Protocol GVRP GARP Multicast Registration Protocol GMRP1.5 GETTING HELP Chapter 1 Virtual Local Area Networks 802.1Q VLAN User’s Guide2.2 VLAN COMPONENTS CHAPTER VLAN OPERATION2.1 DESCRIPTION 2.3 CONFIGURATION PROCESS 2.3.1 Deﬁning a VLAN2.3.2 Classifying Frames to a VLAN Chapter 2 VLAN Operation2.4 VLAN SWITCH OPERATION 2.3.3 Customizing the VLAN Forwarding List2.4.1 Receiving Frames from VLAN Ports Untagged Frames2.4.2 Forwarding Decisions 2.4.2.1 Broadcasts, Multicasts, and Unknown Unicasts2.4.2.2 Known Unicasts Tagged Frames2.5 GARP SWITCH OPERATION CHAPTER VLAN CONFIGURATION 3.1 MANAGING THE SWITCH3.1.1 Switch Without VLANs 802.1Q Switch3.1.2 Switch with VLANs 802.1Q Switch2. Use the Port Assignment Configuration screen for the following 3.2 SUMMARY OF VLAN LOCAL MANAGEMENT 3.2.1 Preparing for VLAN Conﬁguration3.3 802.1Q VLAN CONFIGURATION MENU SCREEN When to UseFigure 3-4 802.1Q VLAN Conﬁguration Menu Screen How to AccessScreen Example Menu Deﬁnitions 802.1Q VLAN Conﬁguration Menu Screen802.1Q VLAN User’s Guide Table 3-1 802.1Q VLAN Conﬁguration Menu Screen Menu Items3.4 DEVICE VLAN CONFIGURATION SCREEN When to UseHow to Access Screen ExampleField Deﬁnitions Device VLAN Conﬁguration Screen802.1Q VLAN User’s Guide Table 3-2 Device VLAN Conﬁguration Screen Field Deﬁnitions3.4.1 Deﬁning a VLAN 3.4.2 Changing the VLAN to FID Association 3.4.3 Renaming a VLAN3.4.4 Deleting a VLAN 3.4.5 Enabling VLANs3.4.6 Disabling VLANs The default VLAN cannot be deleted from the listThe default VLAN cannot be disabled 3.4.7 Changing the Forwarding Mode3.4.8 Paging Through the VLAN List 3.5 PORT ASSIGNMENT CONFIGURATION SCREEN When to UseHow to Access Screen Example3.5.1 Changing the Port Mode Field Deﬁnitions3.5.2 Assigning a VLAN ID When to Use 3.6 PORT FILTERING CONFIGURATION SCREEN3.5.3 Paging Through the Port List How to Access Screen ExampleChapter 3 VLAN Conﬁguration 3-183.6.1 Displaying VLAN IDs Associated with a Port Field Deﬁnitions3.6.2 Selecting the Type of Filtering for a Port 3.7 VLAN FORWARDING CONFIGURATION SCREEN When to UseHow to Access Screen ExampleSee the frame format Tagged or Untagged for the frames 3.7.1 Viewing Current VLAN PortsField Deﬁnitions 3.7.4 Deleting Forwarding List Entries 3.7.2 Paging Through VLAN Forwarding List Entries3.7.3 Adding Forwarding List Entries When to Use 3.8 PROTOCOL VLAN CONFIGURATION SCREEN3.7.5 Changing the Frame Format How to Access Screen ExampleProtocol VLAN Conﬁguration Screen 802.1Q VLAN User’s GuideField Deﬁnitions Chapter 3 VLAN Conﬁguration3-26 802.1Q VLAN User’s GuideProtocol VLAN Conﬁguration Screen 802.1Q VLAN User’s Guide3-27 Table 3-6 Protocol VLAN Conﬁguration Screen Field Deﬁnitions Cont’d3.8.1 Displaying the Current Protocol, VLAN ID, and Port Assignments 3.8.2 Assigning a Protocol Family to a VLAN IDProtocol VLAN Conﬁguration Screen To see if there are VLANs currently assigned to the ProtocolTIP displayed in the Protocol ﬁeld, press ENTER 802.1Q VLAN User’s Guide3.8.3 Displaying the Protocol Types on Current Ports 3.9 PROTOCOL PORTS CONFIGURATION SCREEN When to UseHow to Access Screen ExampleField Deﬁnitions Chapter 3 VLAN Conﬁguration3-32 802.1Q VLAN User’s Guide3.9.1 Adding/Deleting Ports Associated with a VLAN ID 3.10 QUICK VLAN WALKTHROUGH6. Use the arrow keys to highlight the ADD/DEL field It is now time to assign a port to this new VLAN Figure 3-12 Walkthrough Stage Two Figure 3-13 Walkthrough Stage Three 17. Press the SPACE bar to toggle the field to display Enabled 21. Use the arrow keys to highlight the Port field Chapter 3 VLAN Conﬁguration 3-40802.1Q VLAN User’s Guide Figure 3-15 Final Walkthrough Stage802.1Q Switch 4.1 EXAMPLE 1, SINGLE SWITCH OPERATIONCHAPTER EXAMPLES R1 R2 R3B3 B2 B1 4.1.1 Solving the Problem802.1Q Switch 4.1.2 Frame Handling 4.2 EXAMPLE 2, VLANS ACROSS MULTIPLE SWITCHES 4.2.1 Solving the Problem Figure 4-3 Example 2, VLANs Across Multiple SwitchesSwitch 4 is set as follows Switch 2 is set as follows 4.2.2 Frame Handling Figure 4-4 Bridge 1 Broadcasts FramesFigure 4-5 Transmitting to Switch 4.3 EXAMPLE 3, 1D TRUNK CONNECTION TO 802.1Q VLAN NETWORK Figure 4-6 Transmitting to BridgeGreen Incorporated Figure 4-7 Example 3, 1D Trunk Connection to 802.1Q VLAN NetworkUser B 4.3.1 Solving the Problem 4.3.2 Frame Handling Figure 4-8 Bridge 1 Broadcasts Frames Figure 4-9 Switch 2 Forwards to 1Q Trunk Figure 4-10 Switch 1 Forwards to 1D TrunkSwitch 1 checks the Filtering Database for the MAC address of User B. User B’s MAC address is located, and Port 2 is identified as User B’s location. The frame is then checked for eligibility and frame format for Port 2. Since Port 2 is a 1Q Trunk port, it is eligible to transmit frames for all VLANs. The frame is tagged and transmitted out Port 4.4 EXAMPLE 4, ISOLATING NETWORK TRAFFIC ACCORDING TO PROTOCOL 4.4.1 Solving the Problem Figure 4-11 Example 4, Isolating Trafﬁc According to ProtocolSwitch 3 is set as follows Switch 5 is set as follows Port 2, VLAN ID 6, Protocol AppleTalk 802.1Q VLAN User’s Guide Chapter 4 Examples4-22 INDEX Numerics802.1Q VLAN User’s Guide IndexIndex-2 Index-3 Index802.1Q VLAN User’s Guide 802.1Q VLAN User’s Guide IndexIndex-4