Ccna routing and Switching Complete Study Guide

switchport mode dynamic desirable

23:11:37:%LINEPROTO-5-UPDOWN:Line protocol on Interface GigabitEthernet0/13, 

changed state to down

23:11:37:%LINEPROTO-5-UPDOWN:Line protocol on Interface Vlan1, changed state to 

down

23:11:40:%LINEPROTO-5-UPDOWN:Line protocol on Interface GigabitEthernet0/13, 

changed state to up

23:12:10:%LINEPROTO-5-UPDOWN:Line protocol on Interface Vlan1, changed state to 

up

S2(config-if)#

do show int trunk

 

Port        Mode         Encapsulation  Status        Native vlan

Gi0/13      desirable    n-isl          trunking      1

[output cut]

Nice—it worked! With one side in 

Auto

 and the other now in 

Desirable

, DTPs will be 

exchanged and they will trunk. Notice in the preceding output that the mode of S2’s Gi0/13 

link is desirable and that the switches actually negotiated ISL as a trunk encapsulation—

go figure! But don’t forget to notice the native VLAN. We’ll work on the frame-tagging 

method and native VLAN in a minute, but first, let’s configure our other link:

S2(config-if)#

int gi0/14

S2(config-if)#