Different Types of Interfaces on Cisco Routers

The auxiliary port as well as console ports are used for router management. Routers also have ports for LAN and WAN connectivity. The LAN interfaces usually include Ethernet, Fast Ethernet, Giga Ethernet, Fiber Distributed Data Interface (FDDI), and Token Ring. Following is the detail of all types of interfaces of Cisco routers.


Ethernet is typically IEEE 802.3 standard based physical interface of the router. The operating speed of the port is 10 Mbps. The media standard for this interface is 10BaseT.

Fast Ethernet

The Fast Ethernet also is known is the FE interface. It is IEEE 802.3u standard based physical interface. The operating speed of Fast Ethernet is 100 Mbps. The media standard used for Fast Ethernet interface is 100BaseT.

Gigabit Ethernet

Gigabit Ethernet is also known as GE interface. This ports standard is Ethernet IEEE 802.3ab. Gigabit Ethernet can connect at the remarkable speed of 1000mb/s. The media standard used is1000BASE-T

Serial interfaces

A serial interface is a communication interface between two digital systems that transmit data as a series of voltage pulses down a wire. Serial interfaces typically used for WAN connections from ISP  to host. the serial interface provides connectivity types like Frame Relay, T1, T3, etc


Fiber Distributed Data Interface is a set of ANSI and ISO standards for data transmission on fibre optic lines in a local area network (LAN). The range of FDDI can extend in range up to 200 km. FDDI networks operate at 100 Mbps speed and use a token-passing mechanism to prevent collisions.


Token Ring

A token ring network is a local area network (LAN) in which all computers connected in a ring or star topology and pass one or more logical tokens from host to host. Only a host that holds a token can send data, and tokens released when receipt of the data confirmed. Token Ring interfaces can operate at either 4 Mbps or 16 Mbps. Token Ring networks missing from networking industry long way back. New Cisco routers do not have a Token Ring interface.

Loopback interface

A loopback interface is a logical, virtual interface in a Cisco Router. This is not a physical interface like Fast Ethernet interface or Gigabit Ethernet interface. A loopback interface has important uses, for example, as an OSPF Router ID.

Null Interface

A null interface is a virtual interface that discards IP packets. It is to prevent routing loops from occurring in the network. We do not assign the IP address to a null interface.