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]; /* 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⟩