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Chapter 16

Connecting LANs,Backbone Networks,

and Virtual LANs

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16.1 Connecting Devices16.1 Connecting Devices

Repeaters

Hubs

Bridges

Two-Layer Switches

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Figure 16.1 Connecting devices

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Figure 16.2 Repeater

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A repeater connects segments of a LAN.

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A repeater forwards every frame; it has no filtering capability.

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A repeater is a regenerator, not an amplifier.

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Figure 16.3 Function of a repeater

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Figure 16.4 Hubs

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A bridge has a table used in filtering decisions.

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Figure 16.5 Bridge

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A bridge does not change the physical (MAC) addresses in a frame.

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Figure 16.6 Learning bridge

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Figure 16.7 Loop problem

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Figure 16.8 Prior to spanning tree application

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Figure 16.9 Applying spanning tree

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Figure 16.10 Forwarding ports and blocking ports

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16.2 Backbone Networks16.2 Backbone Networks

Bus Backbone

Star Backbone

Connecting Remote LANs

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In a bus backbone, the topology of the backbone is a bus.

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Figure 16.11 Bus backbone

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In a star backbone, the topology of the backbone is a star; the backbone is

just one switch.

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Figure 16.12 Star backbone

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Figure 16.13 Connecting remote LANs

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A point-to-point link acts as a LAN in a remote backbone connected by

remote bridges.

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16.3 Virtual LANs16.3 Virtual LANs

Membership

Configuration

IEEE Standard

Advantages

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Figure 16.14 A switch connecting three LANs

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Figure 16.15 A switch using VLAN software

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Figure 16.16 Two switches in a backbone using VLAN software

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VLANs create broadcast domains.

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