Trunk interface

[Steve Coady]

Hello

I am in process of bringing up new trunk link on a Cisco 3750-48 port switch and see the following:

interface GigabitEthernet1/0/52
 description DMZ_Eth9/31
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 2,3,5,10
 switchport mode trunk
end

Gi1/0/52  DMZ_ Eth9/31  notconnect   1     auto   auto 1000BaseSX SFP

The config shows a trunk config, but the status does not.

I am not ready to bring this link up so the other end is Admin down.

Shouldn't this show the status as TRUNK?

[Steve Coady]

I am expecting this to show "Trunk" but in notconnect status

[Jon Marshall · Accepted solution]

Steve

From memory (so I could be wrong) I don't think it will show as a trunk until you connect it up ie. what you are seeing is normal.

Hopefully if I am misremembering someone else will come along and correct me :-)

Jon

[Steve Coady]

John

Thank you for the response.

I thought that may be the case. I was hoping that was the case, but could not remember for sure.

[InayathUlla Sharieff]

Stee,

Sorry for late answer as Jon said this is expected behaviour the trunk only shown when the negotiation has been completed.

I have connected 3850---3850 box.

CAT3850#show int g2/0/1 status

Port      Name               Status       Vlan       Duplex  Speed Type
Gi2/0/1   connected    notconnect   1            auto   auto 10/100/1000Ba

I have Shutdown one of the link which means the negotiation has been stopped or you can say that there is nothing flowing across this link hence the status would be notconnect which means there is nothing connected to this link though you have the link connected.

Most Cisco switches default to having a port in the notconnect state. This means it is currently not connected to anything, but it will connect if it has a good connection to another operational device. If you connect a good cable to two switch ports in the notconnect state, the link light must become green for both ports, and the port status must indicate connected. This means that the port is up as far as Layer 1 (L1) is concerned.

For CatOS, you can use the show port command to verify whether the port has a connected or notconnect status, or whether it is another state that would cause connectivity to fail, like disabled or errdisable.

Only when I unshut the port at the other end the port would come up.

HTH