CCNA Cisco Certified Network Associate Study Guide - FTP Server

Local Management Interface (LMI)
Frame Relay 493
The Local Management Interface (LMI) was developed in 1990 by Cisco
Systems, StrataCom, Northern Telecom, and Digital Equipment Corporation
and became known as the Gang-of-Four LMI or Cisco LMI. This gang
took the basic Frame Relay protocol from the CCIT and added extensions
onto the protocol features that allow internetworking devices to communicate
easily with a Frame Relay network.
The LMI is a signaling standard between a CPE device (router) and a frame
switch. The LMI is responsible for managing and maintaining status between
these devices. LMI messages provide information about the following:
Keepalives Verify data is flowing
Multicasting Provides a local DLCI PVC
Multicast addressing Provides global significance
Status of virtual circuits Provides DLCI status
Beginning with IOS version 11.2, the LMI type is auto-sensed. This enables the
interface to determine the LMI type supported by the switch.
If you’re not going to use the auto-sense feature, you’ll need to check with
your Frame Relay provider to find out which type to use instead. The default
type is Cisco, but you may need to change to ANSI or Q.933A. The three different
LMI types are depicted in the router output below.
RouterA(config-if)#frame-relay lmi-type ?
cisco
ansi
q933a
As seen in the output, all three standard LMI signaling formats are
supported:
Cisco LMI defined by the Gang of Four (default)
ANSI Annex D defined by ANSI standard T1.617
ITU-T (q933a) Annex A defined by Q.933