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ng_sscfu(4)

NAME

     ng_sscfu -- netgraph SSCF at the UNI node type

SYNOPSIS

     #include <netnatm/saal/sscopdef.h>
     #include <netnatm/saal/sscfudef.h>
     #include <netgraph/atm/ng_sscfu.h>

DESCRIPTION

     The sscfu netgraph node type implements ITU-T recommendation Q.2130.
     This recommendation specifies the Service Specific Coordination Function
     at the UNI.  This is a thin sub-layer between the SSCOP (see ng_sscop(4))
     and the UNI signalling.  This node does not really implement a protocol
     but provides a mapping between the signals at the upper layer of the
     SSCOP and the signals the UNI expects at its lower layer.	It also pro-
     vides default values for the parameters of the SSCOP.

     After creation of the node, the SSCF instance must be created by sending
     an ``enable'' message to the node.  If the node is enabled, default SSCOP
     parameters can be retrieved and set in the corresponding SSCOP instance.

     The node is shut down either by a NGM_SHUTDOWN message, or when all hooks
     are disconnected.

HOOKS

     Each sscfu node has two hooks with fixed names:

     lower  This hook is the interface to the SSCOP.  The interface expected
	    here is exactly that which is exported by the ng_sscop(4) node
	    type.

     upper  This is the interface to the UNI.  It uses the following message
	    format:

	    struct sscfu_arg {
		    uint32_t sig;
		    u_char   data[];
	    };

	    The sig field is one of the following signals:

	    enum saal_sig {
		SAAL_ESTABLISH_request,     /* U -> SAAL: (UU) */
		SAAL_ESTABLISH_indication,  /* SAAL -> U: (UU) */
		SAAL_ESTABLISH_confirm,     /* SAAL -> U: (UU) */
		SAAL_RELEASE_request,	    /* U -> SAAL: (UU) */
		SAAL_RELEASE_confirm,	    /* SAAL -> U: */
		SAAL_RELEASE_indication,    /* SAAL -> U: (UU) */
		SAAL_DATA_request,	    /* U -> SAAL: (DATA) */
		SAAL_DATA_indication,	    /* SAAL -> U: (DATA) */
		SAAL_UDATA_request,	    /* U -> SAAL: (UDATA) */
		SAAL_UDATA_indication,	    /* SAAL -> U: (UDATA) */
	    };

	    The arrows in the comment show the direction of the signal,
	    whether it is a signal that comes out of the node (`->'), or is
	    sent by the node user to the node (`<-').  The type of the data

     NGM_SSCFU_GETDEFPARAM
	     This message returns a sscop_param structure, which contains the
	     default parameters for the SSCOP at the UNI.  This structure
	     should be used for a NGM_SSCOP_SETPARAM message to the SSCOP node
	     below the SSCF.

     NGM_SSCFU_ENABLE
	     This message creates the actual SSCF instance and initializes it.
	     Until this is done, parameters may neither be retrieved nor set,
	     and all messages received on any hook are discarded.

     NGM_SSCFU_DISABLE
	     Destroy the SSCF instance.  After this, all messages on any hooks
	     are discarded.

     NGM_SSCFU_GETDEBUG
	     Retrieve the debugging flags in a uint32_t.

     NGM_SSCFU_SETDEBUG
	     Set debugging flags.  The argument must be a uint32_t.

     NGM_SSCFU_GETSTATE
	     Retrieve the current state of the SSCFU instance in a uint32_t.
	     If the node has not been enabled, 0 is returned.

SEE ALSO

     netgraph(4), ng_atm(4), ng_sscop(4), ngctl(8)

AUTHORS

     Harti Brandt <harti@FreeBSD.org>

FreeBSD 5.4		       October 24, 2003 		   FreeBSD 5.4

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