show int fas 0/14 switchport question

szmarcek

Hi,
While preparing for BCMSN, I practiced using bpdu filter on one of switch's interfaces

R6A2950_0x2(config)#int fas 0/14
R6A2950_0x2(config-if)#spanning-tree bpdufilter enable

after that I connected the port 0/14 to a different switch which was sending BPDUs to test how will the port behave.

00:12:04: %LINK-3-UPDOWN: Interface FastEthernet0/14, changed state to down
R6A2950_0x2(config)#
00:12:07: %LINK-3-UPDOWN: Interface FastEthernet0/14, changed state to up
R6A2950_0x2(config)#

Everything went as described in the book. However, I noticed a strange thing (at least for me:). Although the port was previously hardcoded with switchport access vlan 30 (see running-config below)

R6A2950_0x2#show running-config
Building configuration...

Current configuration : 2819 bytes
!
spanning-tree mode pvst
no spanning-tree optimize bpdu transmission
spanning-tree extend system-id
!

!
interface FastEthernet0/14
description Dell
switchport access vlan 30
spanning-tree portfast
spanning-tree bpdufilter enable

when you check it with show int fas 0/14 switchport command the administrative mode shows as Administrative Mode: dynamic desirable

R6A2950_0x2#show int fas 0/14 switchport
Name: Fa0/14
Switchport: Enabled
Administrative Mode: dynamic desirable
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 30 (VLAN0030)
Trunking Native Mode VLAN: 1 (default)
Voice VLAN: none


My question is why do administrative mode in show int fas 0/14 switchport shows Administrative Mode:dynamic desirable while the show running config shows switchport access vlan 30 (I configured this port earlier using switchport access vlan 30)?

What am I missing ?

nel

i dont think you understand the output correctly. You state you have used switch access vlan 30 - this defined the data vlan the port will be in. This can be seen by the output:

Access Mode VLAN: 30 (VLAN0030)

You are referring to the mode of the port. By default on your switch it is dyanmic desirable. This can be seen in:

Administrative mode: dynamic desirable

If you looked in your config for port 14 you have not defined the mode of the port using switch mode parameter command. This will then be reflected in the output for the administrative mode. So if you wanted an access port you would use switch mode access under int fa0/14. If you wanted a trunk then use switch mode trunk and so on.

The operational mode displays the current mode the port is operating in. At the moment yours is a trunk as defined by:

Operational Mode: trunk

if you go into the port interface and use something like switch mode trunk the admin mode will then change to and admin state of trunk.

I hope i make some sense there, im still hungover

szmarcek

Thanks for help. I must have forgot to change the interface mode to trunk, I guess.

I have tried switchport mode trunk and it worked as you described.