1 © 2003, Cisco Systems, Inc. All rights reserved. CCNA 3 v3.0 Module 9 VLAN Trunking Protocol Cisco Networking Academy

222 © 2003, Cisco Systems, Inc. All rights reserved. Objectives Trunking VTP Inter-VLAN routing

333 © 2003, Cisco Systems, Inc. All rights reserved. Trunking Concepts Trunking links between switches allow for the sharing of VLAN information.

444 © 2003, Cisco Systems, Inc. All rights reserved. Frame Filtering

555 © 2003, Cisco Systems, Inc. All rights reserved. Frame Tagging

666 © 2003, Cisco Systems, Inc. All rights reserved. VLANs and Trunking “Multi-colored link”

777 © 2003, Cisco Systems, Inc. All rights reserved. Inter-Switch Link Protocol – Cisco

888 © 2003, Cisco Systems, Inc. All rights reserved. Frame Tagging and Encapsulation Methods Cisco IEEE

999 © 2003, Cisco Systems, Inc. All rights reserved. VLAN Trunking Protocol (VTP) The role of VTP is to maintain VLAN configuration consistency across a common network administration domain.

10 © 2003, Cisco Systems, Inc. All rights reserved. VTP Mode Comparison A transparent switch will not modify its database when updates are received, nor will the switch send out an update indicating a change in its VLAN status. Except for forwarding VTP advertisements, VTP is disabled on a transparent switch.

11 © 2003, Cisco Systems, Inc. All rights reserved. VTP Operation

12 © 2003, Cisco Systems, Inc. All rights reserved. VTP Implementation There are two types of VTP advertisements: 1.Requests from clients that want information at bootup 2.Responses from servers There are three types of VTP messages: 1.Advertisement requests 2.Summary advertisements 3.Subset advertisements

13 © 2003, Cisco Systems, Inc. All rights reserved. VTP and Trunk Links VTP messages are encapsulated in either ISL or IEEE 802.1Q protocol frames, and passed across trunk links to other devices.

14 © 2003, Cisco Systems, Inc. All rights reserved. VTP Basic Configuration Steps 1.Determine the version number 2.Choose the domain 3.Choose the VTP mode Server or Client or Transparent Default is Server 4.Password protect the domain

15 © 2003, Cisco Systems, Inc. All rights reserved. VTP Server vs. VTP Client VLANs can only be created or deleted on a VTP Server switch. VTP Client switches cannot create or delete VLANs. –However, VTP Clients can update VTP Servers if they have a higher revision number Transparent Switches can add and delete VLANs but this information is not passed to the other switches in the VTP Domain.

16 © 2003, Cisco Systems, Inc. All rights reserved. Inter-VLAN Routing

17 © 2003, Cisco Systems, Inc. All rights reserved. Inter-VLAN Issues and Solutions Two of the most common issues that arise in a multiple-VLAN environment are as follows: 1.The need for end-user devices to reach nonlocal hosts 2.The need for hosts on different VLANs to communicate

18 © 2003, Cisco Systems, Inc. All rights reserved. “Router-on-a-Stick” I’m like a lollipop!

19 © 2003, Cisco Systems, Inc. All rights reserved. Physical and Logical Interfaces IEEE 802.1q is more common

20 © 2003, Cisco Systems, Inc. All rights reserved. Dividing Physical Interfaces into Subinterfaces

21 © 2003, Cisco Systems, Inc. All rights reserved. Configuring Inter-VLAN Routing

22 © 2003, Cisco Systems, Inc. All rights reserved. Two Options for Inter-VLAN Routing If "native" command is NOT supported: interface Fastethernet0/0 description Dot1q Trunk to Switch-2950 ip address speed 100 full-duplex ! interface Fastethernet0/0.10 encapsulation dot1q 10 ip address ! interface Fastethernet0/0.20 encapsulation dot1q 20 ip address If "native" command IS supported: interface Fastethernet0/0 description Dot1q Trunk to Switch-2950 no ip address speed 100 full-duplex ! interface Fastethernet0/0.1 encapsulation dot1q 1 native ip address ! interface Fastethernet0/0.10 encapsulation dot1q 10 ip address ! interface Fastethernet0/0.20 encapsulation dot1q 20 ip address

23 © 2003, Cisco Systems, Inc. All rights reserved. The ‘native’ Command The ‘encapsulation dot1Q 1 native’ command was added in Cisco IOS version 12.1(3)T. If you are using an earlier version of Cisco IOS, refer to the 802.1Q configuration on the previous slide. The minimum IOS release required to support 802.1Q trunking on a 2620 or 2621 router is 12.0(1)T. The native VLAN is used for untagged traffic when the port is in 802.1Q trunking mode. –While configuring 802.1Q trunking, it is very important to keep in mind that the native VLAN must be configured the same on each side of the trunk link.