What firmware release are you running? Perhaps the following is your problem (taken from
S2700 and S3700 Product Documentation :.. > Maintenance and Troubleshooting > FAQs (Applicable to Multiple Versions) > Interface Management:
Can I Assign an IP Address to a Physical Interface?
Physical interfaces are categorized as management interfaces and service interfaces. An MEth management interface is a Layer 3 interface that can be assigned an IP address. A management interface cannot work in Layer 2 mode.
A service interface is a Layer 2 interface and cannot be assigned an IP address. You can configure a VLANIF interface and assign an IP address to the VLANIF interface. The following configuration is an example:
<Quidway> system-view
[Quidway] vlan 10
[Quidway-vlan10] quit
[Quidway] interface vlanif 10
[Quidway-Vlanif10] ip address 192.168.1.10 24
For switches in V200R005C00 and later versions, running the undo portswitch command can switch an Ethernet interface to a Layer 3 interface, and then you can assign an IP address to the interface.