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Virtual LANs and VLAN Trunking

Dec 25, 2009

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This chapter is from the book 

CCIE Routing and Switching Certification Guide, 4th Edition

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Foundation Summary

This section lists additional details and facts to round out the coverage of the topics in this chapter. Unlike most of the Cisco Press Exam Certification Guides, this "Foundation Summary" does not repeat information presented in the "Foundation Topics" section of the chapter. Please take the time to read and study the details in the "Foundation Topics" section of the chapter, as well as review items noted with a Key Topic icon.

Table 2-10 lists some of the most popular IOS commands related to the topics in this chapter. (The command syntax was copied from the Catalyst 3550 Multilayer Switch Command Reference, 12.1(20)EA2. Note that some switch platforms may have differences in the command syntax.)

Table 2-10. Catalyst IOS Commands Related to Chapter 2

Command	Description
show mac address-table [aging-time \| count \| dynamic \| static] [address hw-addr] [interface interface-id] [vlan vlan-id]	Displays the MAC address table; the security option displays information about the restricted or static settings
show interfaces [interface-id \| vlan vlan-id] switchport \| trunk]	Displays detailed information about an interface operating as an access port or a trunk
show vlan [brief \| id vlan-id \| name vlan-name \| summary]	EXEC command that lists information about VLAN
show vlan [vlan]	Displays VLAN information
show vtp status	Lists VTP configuration and status information
switchport mode {access \| dot1q-tunnel \| dynamic {auto \| desirable} \| trunk}	Configuration command setting nontrunking (access), trunking, and dynamic trunking (auto and desirable) parameters
switchport nonegotiate	Interface subcommand that disables DTP messages; interface must be configured as trunk or access port
switchport trunk {allowed vlan vlan-list} \| {encapsulation {dot1q \| isl \| negotiate}} \| {native vlan vlan-id} \| {pruning vlan vlan-list}	Interface subcommand used to set parameters used when the port is trunking
switchport access vlan vlan-id	Interface subcommand that statically configures the interface as a member of that one VLAN

Table 2-11 lists the commands related to VLAN creation—both the VLAN database mode configuration commands (reached with the vlan database privileged mode command) and the normal configuration mode commands.

Table 2-11. Catalyst 3550 VLAN Database and Configuration Mode Command List

VLAN Database	Configuration
vtp {domain domain-name \| password password \| pruning \| v2-mode \| {server \| client \| transparent}}	vtp {domain domain-name \| file filename \| interface name \| mode {client \| server \| transparent} \| password password \| pruning \| version number}
vlan vlan-id [backupcrf {enable \| disable}] [mtu mtu-size] [name vlan-name] [parent parent-vlan-id] [state {suspend \| active}]	vlan vlan-id¹
show {current \| proposed \| difference}	No equivalent
apply \| abort \| reset	No equivalent

Table 2-12. Cisco IOS PPPoE Client Commands

Command	Description
pppoe enable	Enables PPPoE operation on an Ethernet interface or subinterface
pppoe-client dial-pool-number number	Configures the outside Ethernet interface on a router for PPPoE operation and ties it to a dialer interface
debug pppoe [data \| errors \| events \| packets]	Enables debugging for PPPoE troubleshooting

Memory Builders

The CCIE Routing and Switching written exam, like all Cisco CCIE written exams, covers a fairly broad set of topics. This section provides some basic tools to help you exercise your memory about some of the broader topics covered in this chapter.

Fill In Key Tables from Memory

Appendix G, "Key Tables for CCIE Study," on the CD in the back of this book contains empty sets of some of the key summary tables in each chapter. Print Appendix G, refer to this chapter's tables in it, and fill in the tables from memory. Refer to Appendix H, "Solutions for Key Tables for CCIE Study," on the CD to check your answers.

Definitions

Next, take a few moments to write down the definitions for the following terms:

VLAN, broadcast domain, DTP, VTP pruning, 802.1Q, ISL, native VLAN, encapsulation, private VLAN, promiscuous port, community VLAN, isolated VLAN, 802.1Q-in-Q, Layer 2 protocol tunneling, PPPoE, DSL.

Refer to the glossary to check your answers.

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