iuwne10 s01 l09

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-1

Wireless Fundamentals

Reviewing the Wireless Frame Journey: End-to-End

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-2

Discovering the Network

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-3

Getting Connected

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-4

Clients in Cells

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-5

Sending in the Cell

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-6

Creating the 802.11 Frame

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-7

Acknowledging the Frame

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-8

AP Forwarding to Network

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-9

AP Forwarding to Controller

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-10

In the Controller, Header Is Rewritten

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-11

Wired Segment

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-12

In the Controller, on the Way Back

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-13

The AP Forwards the Answer

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-14

Using the Optimal Speed

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-15

The Right Client Processes the Frame

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-16

All Frames Are Sent to the Same AP Radio

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-17

Controller Needs to Keep SSIDs Separated

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-18

VLANs

VLAN = Broadcast Domain = Logical Network (Subnet)

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-19

VLAN Operation

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-20

802.1Q Trunking

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-21

Understanding Native VLANs

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-22

Mapping SSIDs to VLANs

Each SSID is mapped to a VLAN:1 SSID => 1 subnet and 1 VLAN tag

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-23

Configuring VLANs and Trunks

1. Create or modify a VLAN on the switch.2. Assign switch ports to a VLAN and verify.3. Save the VLAN configuration.4. Configure and verify 802.1Q trunks, and save.

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-24

The maximum number of VLANs is switch-dependent. VLAN 1 is the factory default Ethernet VLAN. Cisco Discovery Protocol is sent on native untagged VLAN. The Cisco Catalyst switch IP address is in the management

VLAN (VLAN 1 by default).

VLAN Creation Guidelines

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-25

Adding a VLAN

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-26

Assigning Switch Ports to a VLAN

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-27

Verifying VLAN Membership

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-28

Verifying VLAN Membership (Cont.)

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-29

802.1Q Trunking

Make sure that the native VLAN for an 802.1Q trunk is the same on both ends of the trunk link.Note that native VLAN frames are untagged.

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-30

Configuring 802.1Q Trunking

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-31

Verifying a Trunk

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-32

Summary

When wireless frames transit to the wired side of the network, the body is unchanged but the header is transformed to a 802.3 header.

VLANs provide on Ethernet segments the segmentation that SSIDs bring to the wireless side.

VLANs create tags on frames, and trunks carry these framed tags from switch to switch.

VLAN membership can be static or dynamic. Controllers tag frames, and the other end, which is a switch, has

to be in trunk mode. A switch has a “native VLAN,” which is usually not tagged on a

trunk. Configuring static VLANs consists of creating them and assigning

a port to them.

© 2008 Cisco Systems, Inc. All rights reserved. IUWNE v1.0—1-33