Trunking between 2 3550's

Damienm30

Guys,

I am trying to set up a trunk link between 2 3550 switches but cannot get the trunk link to form. I am connecting port f0/1 on the access switch to port f0/1 on the distribution switch. I have run the following commands under f0/1 on each switch:

interface FastEthernet0/1
switchport trunk encapsulation dot1q
switchport trunk native vlan 99
switchport mode trunk
switchport nonegotiate
logging event trunk-status
no shut

The output from sh int f0/1 switchport on both switches is as follows:

Access Switch

Name: Fa0/1
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: down
Administrative Trunking Encapsulation: dot1q
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 99 (Inactive)
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled

Distribution Switch

Name: Fa0/1
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: down
Administrative Trunking Encapsulation: dot1q
Negotiation of Trunking: Off
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 99 (Inactive)
Administrative Native VLAN tagging: enabled
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk Native VLAN tagging: enabled
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk associations: none
Administrative private-vlan trunk mappings: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
--More--

Notce that the operational Mode is DOWN. I have tried lots of different things but cannot get this trunk to form. I will be eternally grateful to anyone who cna help.

Thanks a million
Damien

wastedtime

You may want to make sure the cable is a crossover cable and double check there isn't a problem with the cable.

accely

wastedtime wrote: »

You may want to make sure the cable is a crossover cable and double check there isn't a problem with the cable.

I agree here. I've mistakenly had a ST cable plugged many times! Make sure it's a cross over

Damienm30

Guys,

Thank you so much for saving me! I have spent some much time inspecting configs and reading Cisco docs that I overlooked the cabling. I am indeed using the wrong cable. dooooh!! Guess I learned lots about Trunking as a result. Thanks again for the prompt replies.

Damien

sides14

I always use different color cables to prevent this type of situation.

wastedtime

I was figuring that most people now a day’s use auto sensing mdi/mdi-x devices that they sometimes forget when a device isn't. I think I still got a switch (switching hub I believe is what they called it) somewhere that has a dedicated uplink port.