Ch. 8: Implementing Ethernet Virtual LANs

Question 1

802.1Q

Answer 1

The IEEE standardized protocol for VLAN trunking, which also includes RSTP details.

Question 2

trunk

Answer 2

In campus LANs, an Ethernet segment over which the devices add a VLAN header that identifies the VLAN in which the frame exists.

Question 3

trunking administrative mode

Answer 3

The configured trunking setting on a Cisco switch interface, as configured with the switchport mode command.

Question 4

trunking operational mode

Answer 4

The current behavior of a Cisco switch interface for VLAN trunking.

Question 5

virtual LAN (VLAN)

Answer 5

A group of devices, connected to one or more switches, with the devices grouped into a single broadcast domain through switch configuration. VLANs allow switch administrators to separate the devices connected to the switches into separate VLANs without requiring separate physical switches, gaining design advantages of separating the traffic without the expense of buying additional hardware.

Question 6

VLAN Trunking Protocol (VTP)

Answer 6

A Cisco-proprietary messaging protocol used between Cisco switches to communicate configuration information about the existence of VLANs, including the VLAN ID and VLAN name.

Question 7

VTP transparent mode

Answer 7

One of three VTP operational modes. Switches in transparent mode can configure VLANs, but they do not tell other switches about the changes, and they do not learn about VLAN changes from other switches.

Question 8

multilayer switch

Answer 8

A LAN switch that can also perform Layer 3 routing functions. The name comes from the fact that this device makes forwarding decisions based on logic from multiple OSI layers (Layers 2 and 3).

Question 9

access interface

Answer 9

A LAN network design term that refers to a switch interface connected to end-user devices, configured so that it does not use VLAN trunking.

Question 10

trunk interface

Answer 10

A switch interface configured so that it operates using VLAN trunking (either 802.1Q or ISL).

Question 11

data VLAN

Answer 11

A VLAN used by typical data devices connected to an Ethernet, like PCs and servers. Used in comparison to a voice VLAN.

Question 12

voice VLAN

Answer 12

A VLAN defined for use by IP Phones, with the Cisco switch notifying the phone about the voice VLAN ID so that the phone can use 802.1Q frames to support traffic for the phone and the attached PC (which uses a data VLAN).

Question 13

native VLAN

Answer 13

The one VLAN ID on any 802.1Q VLAN trunk for which the trunk forwards frames without an 802.1Q header.

Question 14

default VLAN

Answer 14

A reference to the default setting of 1 (meaning VLAN ID 1) on the switchport access vlan vlan-id interface subcommand on Cisco switches, meaning that by default, a port will be assigned to VLAN 1 if acting as an access port.

Question 15

static access interface

Answer 15

A LAN network design term, synonymous with the term access interface, but emphasizing that the port is assigned to one VLAN as a result of static configuration rather than through some dynamic process.

Question 16

vlan (vlan-id)

Answer 16

Global config command that both creates the VLAN and puts the CLI into VLAN configuration mode

Question 17

name (vlan-name)

Answer 17

VLAN subcommand that names the VLAN

Question 18

[no] shutdown

Answer 18

VLAN mode subcommand that enables (no shutdown) or disables (shutdown) the VLAN

Question 19

[no] shutdown vlan (vlan-id)

Answer 19

Global config command that has the same effect as the [no] shutdown VLAN mode subcommands

Question 20

vtp mod {server | client | transparent | off}

Answer 20

Global config command that defines the VTP mode

Question 21

switchport mode {access | dynamic {auto | desirable} | trunk}

Answer 21

Interface subcommand that configures the trunking administrative mode on the interface

Question 22

switchport access vlan (vlan-id)

Answer 22

Interface subcommand that statically configures the interface into that one VLAN

Question 23

switchport trunk encapsulation {dot1q | isl | negotiate}

Answer 23

Interface subcommand that defines which type of trunking to use, assuming that trunking is configured or negotiated

Question 24

switchport trunk native vlan (vlan-id)

Answer 24

Interface subcommand that defines the native VLAN for a trunk port

Question 25

switchport nonegotiate

Answer 25

Interface subcommand that disables the negotiation of VLAN trunking

Question 26

switchport voice vlan (vlan-id)

Answer 26

Interface subcommand that defines the voice VLAN on a port, meaning that the switch uses 802.1Q tagging for frames in this VLAN

Question 27

switchport trunk allowed vlan {add | all | except | remove} (vlan-list)

Answer 27

Interface subcommand that defines the list of allowed VLANs

Question 28

show interfaces (interface-id) switchport

Answer 28

Lists information about any interface regarding administrative settings and operational state

Question 29

show interfaces (interface-id) trunk

Answer 29

Lists information about all operational trunks (but no other interfaces), including the list of VLANs that can be forwarded over the trunk

Question 30

show vlan [brief | id (vlan-id)| name (vlan-name) | summary]

Answer 30

Lists information about the VLAN

Question 31

show vlan (vlan)

Answer 31

Displays VLAN information

Question 32

show vtp status

Answer 32

Lists VTP configuration and status information