Implementing VLANs Flashcards
Chapter 11
What is VLAN tagging?
When the sending switch adds another header to the frame before sending it over the trunk. This extra trunking header includes a VLAN identifier (VLAN ID) field so that the sending switch can associate the frame with a particular VLAN ID,
What are the two trunking protocols supported by Cisco switches?
ISL and 802.1q
How does 802.1q tag a frame?
It inserts an extra 4-byte 802.1Q VLAN header into the original frame’s Ethernet header
What fields does an 802.1q tag consist of?
Type, Priority, Flag, and 12-bit VLAN ID. It supports maximum 4094 VLANS
Are packets in the native VLAN tagged?
No
What command configures a switchport to always act as a trunk?
switchport mode trunk
What command configures a switchport to initiate trunking negotiation?
switchport mode dynamic desireable
What command configures a switchport to passively wait for trunk negotiation at which point it will negotiate the trunk?
switchport mode dynamic auto
Switch A is switchport mode trunk and Switch B is switchport mode dynamic auto
Trunk
Switch A is switchport mode dynamic auto and Switch B is switchport mode dynamic auto
No Trunk
Switch A is switchport mode dynamic desireable and Switch B is switchport mode dynamic auto
Trunk
Switch A is switchport mode trunk and Switch B is switchport mode dynamic desireable
Trunk
If a switch has VTP disabled what mode is it in?
Transparent
If a switch has VTP disabled and a user goes into configuration mode, enters ‘vlan 22’ and ‘name Hannah’ will the VLAN configuration show up in the running-config?
Yes
Which show commands identify trunking interfaces?
show interfaces trunk
show interfaces switchport
