NAME
ng_lmi —
frame relay LMI protocol netgraph node
type
SYNOPSIS
#include
<netgraph/lmi/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]; /* bitmap DLCIs seen */ u_char up[NGM_LMI_STAT_ARYSIZE]; /* bitmap DLCIs 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>