Configuring the MDI Type of an Interface
Context
Twisted pairs used to connect Ethernet devices include:
- Straight-through cable: connects devices of different types, such as a switch and a PC or a switch and a router.
- Crossover cable: connects devices of the same type, such as two PCs, two switches, or two routers.
An interface supports the following medium dependent interface (MDI) types, which determine the cable type allowed on the interface:
- Auto
- Normal
- Across
By default, an interface works in auto mode. When the device fails to identify the network cable type on an interface, set the MDI type manually.
When setting the MDI type on an interface, pay attention to the following points:
- When a straight-through cable is used, the local and remote interfaces must use different MDI types, for example, across mode on one end and normal mode on the other end.
- When a crossover cable is used, the local and remote interfaces must use the same MDI type. For example, both ends must use the across or normal mode, or at least one end uses the auto mode.
Procedure
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The Ethernet interface view is displayed.
- Run mdi { across | auto | normal }
The MDI type is configured for the Ethernet interface.
By default, an Ethernet interface works in auto mode and automatically identifies the network cable type.