NAME

       ng_lmi — frame relay LMI protocol netgraph node type

SYNOPSIS

       #include <sys/types.h>
       #include <netgraph/ng_lmi.h>

DESCRIPTION

       The  lmi node type performs the frame relay LMI protocol.  It supports the ITU Annex A, ANSI Annex D, and
       Group-of-four LMI types.  It also supports auto-detection of the LMI type.

       To enable a specific LMI type, connect the corresponding hook (annexA, annexD, or group4) to  DLCI  0  or
       1023  of  a  ng_frame_relay(4)  node.   Typically, Annex A and Annex D live on DLCI 0 while Group-of-four
       lives on DLCI 1023.

       To enable LMI type auto-detection, connect the auto0 hook to DLCI 0 and the auto1023 hook to  DLCI  1023.
       The  node  will  attempt  to automatically determine which LMI type is running at the switch, and go into
       that mode.

       Only one fixed LMI type, or auto-detection, can be active at any given time.

       The NGM_LMI_GET_STATUS control message can be used at any time to query the current  status  of  the  LMI
       protocol and each DLCI channel.  This node also supports the NGM_TEXT_STATUS control message.

HOOKS

       This node type supports the following hooks:

       annexA    ITU Annex A LMI hook.

       annexD    ANSI Annex D LMI hook.

       group4    Group-of-four LMI hook.

       auto0     Auto-detection hook for DLCI 0.

       auto1023  Auto-detection hook for DLCI 1023.

CONTROL MESSAGES

       This node type supports the generic control messages, plus the following:

       NGM_LMI_GET_STATUS
            This command returns status information in a struct nglmistat:

                #define NGM_LMI_STAT_ARYSIZE   (1024/8)

                struct nglmistat {
                  u_char  proto[12];    /* Active proto (same as hook name) */
                  u_char  hook[12];     /* Active hook */
                  u_char  fixed;        /* If set to fixed LMI mode */
                  u_char  autod;        /* If currently auto-detecting */
                  u_char  seen[NGM_LMI_STAT_ARYSIZE];   /* DLCIs ever seen */
                  u_char  up[NGM_LMI_STAT_ARYSIZE];     /* DLCIs currently up */
                };

       NGM_TEXT_STATUS
            This generic message returns is a human-readable version of the node status.

SHUTDOWN

       This  node  shuts  down  upon  receipt  of  a  NGM_SHUTDOWN  control message, or when all hooks have been
       disconnected.

SEE ALSO

       netgraph(4), ng_frame_relay(4), ngctl(8)

       ANSI T1.617-1991 Annex D.

       ITU-T Q.933 Digital Subscriber Signaling System No. 1 - Signaling Specification for Frame Mode Basic Call
       Control, Annex A.

HISTORY

       The ng_lmi node type was implemented in FreeBSD 4.0.

AUTHORS

       Julian Elischer <julian@FreeBSD.org>

Debian                                          November 13, 2012                                      NG_LMI(4)