VLANs Flashcards
what is a lan
broadcast domain
vlans allow you to
split a a switch into multiple broadcast domains
why have vlans
performance
security
less hosts receive broadcast frames
flexible designs
this is needed to use vlans over multiple switches
trunking
trunking adds this to the frame
header with vlan id
how to configure int with vlan
switchport access vlan 3
set interface to only access
switchport mode access
show vlans, ports status
show vlan brief
configure a range of ints with vlans
int range fa 0/13-14
switchport access vlan 3
enable trunk mode on a port
switchport mode trunk
interface mode table
A Da T Dd A A X A A A T T X T T T A T T T
IP phones have these embedded
mini switch with 2 vlans
2 vlans in an ip phone
data vlan for end device
voice vlan for phone traffic
once in conf t - int gig 0/2, commands to config data and voice vlans
switchport mode access
switchport access vlan 10
switchport voice vlan 11
command to verify interface configs
show interfaces Fa 0/4 switchport
show trunk interfaces
show interfaces trunk
does voice vlan appear as a trunk interface
no
show all vlan and status
show vlan
steps to troubleshoot vlan
check they are allowed, defined,active
check both ends vlan lists
check trunk admin modes
check both ends native vlan settings
what happens when one int is trunk but destination interface isnt
destination drops all non native frames, accepting native because it is untagged
view allowed vlan list
switchport trunk allowed vlan
