8 - Implementing Ethernet Virtual LANS

Question 1

802.1Q

Answer 1

802.1Q is the standard protocol for this tag. The most critical piece of information (for this discussion) in this tag is the VLAN ID.

Question 2

access interface

Answer 2

access interface
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 3

data VLAN

Answer 3

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

Question 4

broadcast domain

Answer 4

A set of all devices that receive broadcast frames originating from any device within the set. Devices in the same VLAN are in the same broadcast domain.

Question 5

IEEE 802.1Q

Answer 5

The IEEE standard VLAN trunking protocol. 802.1Q includes the concept of a native VLAN, for which no VLAN header is added, and a 4-byte VLAN header is inserted after the original frame’s Type/Length field.

Question 5

native VLAN

Answer 5

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

Question 5

static access interface

Answer 5

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 5

trunk

Answer 5

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

Question 5

trunk interface

Answer 5

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

Question 6

trunking

Answer 6

trunking
Also called VLAN trunking. A method (using either the Cisco ISL protocol or the IEEE 802.1Q protocol) to support multiple VLANs, allowing traffic from those VLANs to cross a single link.

Question 7

trunking administrative mode

Answer 7

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

Question 7

trunking operational mode

Answer 7

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

Question 7

virtual LAN (VLAN)

Answer 7

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 8

VLAN Trunking Protocol (VTP)

Answer 8

VLAN Trunking Protocol (VTP)
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 9

VTP transparent mode

Answer 9

VTP transparent mode
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 10

voice VLAN

Answer 10

voice VLAN
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 11

default VLAN

Answer 11

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.