Question about Port-Channel configuration.

[helloworld.dreamer]

interface Port-channel100
 switchport
 switchport access vlan 1
 switchport access vlan 1
 ip address 1.1.1.1 255.255.255.254

 Have you met this kind of configuration in Cisco Switch- 15.2? I don't think that is right configuration, because "switchport" and "IP address" appear at the same time under one interface. I also tried many device. Sounds like this kind of configuration can not be accepted by Cisco switch. But, we do see this configuration sending from customer. Do you know why it is?

[MHM Cisco World]

Friend 

Swithcport command use only for l2 interface (including port channel)

Here I see you assign IP to l2 port that not work

So you need to decided this port will be l2 or l3 

To make port l3 and assign IP you need to use no switchport 

MHM

[Torbjørn]

That configuration is indeed odd. My guess would be that the "ip address" line is a remnant after converting the interface from a routed port to a switchport, and that it doesn't actually do anything in its current state(switchport mode). Also note that portchannel interfaces can't be converted from switched to routed without recreating it.

[David Ruess]

You can in fact have all kinds of configurations on a port. What is actually active and functional is a result of the command that takes precedence...in this case the IP address command. While it does leave clutter and confusion only some of those commands are actually working.

Edited: IP took precedence, not switchport

-David

[Joseph W. Doherty]

As @David Ruess notes, interfaces often allow configuration statements to remain that are not being used.  As he also describes it does make for clutter and might cause confusion.

Personally, I don't know why Cisco allows this, perhaps either devs too "lazy" to remove inactive config statements or it's a feature to make it easy to switch a port between specific role usage minimizing port config changes.

[helloworld.dreamer]

Based on the routing table, this interface is used as L3 forwarding....... Sounds like Device treats this as L3 interface, instead of L2 interface. REALLY ODD! It is the first time for me to see the interface with "switchport" command to be treated as L3 interface! Ohh.

[MHM Cisco World]

Can I know your SW IOS XE ver.

I think it is bug

MHM

[MHM Cisco World]

Friend if the port is l2 then it never accept any command of l3. What ever the order 

You need always no switchport the  port start accept l3 command.

Share ios xe ver. Let me check if Port-channel pass above step and there is bug 

MHM

[Torbjørn]

WOW! That's a surprise. I have incorrectly assumed that the "switchport" command was the absolute method of selecting interface mode. You live you learn. Thank you for checking

EDIT: I am unable to replicate this on IOSvL2, how did you achieve this?

[helloworld.dreamer]

I don't think your statement is wrong. Based on my knowledge, when interface is set as "switchport", it should be treated as L2 interface. I am with you. To be frank, I am also feeling surprise about this customer's configuration. We have asked for customer meeting to take a look this device. Will update here later.  

[MHM Cisco World]

Totally agree with You

Again I need to notice you we don't talk about physical port we talk about port-channel.

So there is additional check here 

If you can check port member of this port-channel is it l2 or l3.

MHM

[Filip Po]

This configuration should be achieved by creating an SVI L3 VLAN 1 interface with IP address 1.1.1.1/31.
The Portchannel should be connected to an L3 device on the other end.
But the provived config is not possible. If there is an intent, you have to listen to the customer and provide them with the right solution.