Frame Relay Local Management Interface (LMI)

The Frame Relay has many different types of interface to monitor it and handle the situations. The management interface is the further extension of the protocols that are included in the Frame Relay. These extensions help us to monitor the status of the Frame Relay network and keeping the future in the mind these protocols are set for increasing the capabilities of the systems. Local management interface is concerned with the transfer of data and keeping the router intact with the network so that the data can be sent and received. The Local Management Interface extensions also allow DLCI values to be given the global importance and can be used for data transfer by using these figures.

There are two main companies that have developed the local management interface standards that are followed all over the world. They are ANSI and the ITU-T. A Cisco router interface that is using the Frame Relay encapsulation will automatically sense the type of LMI and will run according to it. Sometimes it is also possible that you might have to set the interface manually.

The following are the LMI types supported on the Frame Relay interface:

•    Cisco. This is the “Group of Four” LMI type, and is the default used on Frame Relay interfaces prior to IOS version 11.2. It uses DLCI 1023 to exchange status information.
•    ANSI. This is the LMI type defined by ANSI. It uses DLCI 0 to exchange status information.
•    Q.933a. this is the LMI type defined by the ITU-T. It uses DLCI 0 to exchange status information.

It is very important that the working router and its local Frame Relay switch must have the similar kind of local management interface to generate the diagnostic messages between them. Otherwise this would create problems and also make the network disable.