SSCF UNI Design
	===============

SAP_SSCF_UNI Interface
----------------------
This is the stack SAP interface between the UNI signalling layer (eg. Q.2931)
and the SSCF module.  The stack commands defined for this interface are modeled
after the SSCF protocol specification primitives AAL-xxx.  See the protocol
specification documents referenced below for full descriptions of the SSCF UNI
interface presented to the signalling user.


o The following stack commands are sent from the signalling module to SSCF:

Stack Command:	SSCF_UNI_INIT
Description:	Initialize a SAP instance.  This should be the first stack
		command issued across the SAP instance after the service stack
		has been successfully instantiated.
Argument 1:	Specifies the UNI version to be used for this stack instance.
		(enum uni_vers)
Argument 2:	Not used.


Stack Command:	SSCF_UNI_TERM
Description:	Terminate a SAP instance.  This must be the last stack command
		issued across the SAP instance.  The stack instance will be
		deleted upon completion of this command.
Argument 1:	Not used.
Argument 2:	Not used.


Stack Command:	SSCF_UNI_ESTABLISH_REQ
Description:	Request the establishment of an assured SAAL connection to the
		SAAL peer entity.
Argument 1:	Not used.
Argument 2:	Not used.


Stack Command:	SSCF_UNI_RELEASE_REQ
Description:	Request the termination of an assured SAAL connection to the
		SAAL peer entity.
Argument 1:	Specifies whether future session establishment indications from
		the SAAL peer should be processed.  Valid values are 
		SSCF_UNI_ESTIND_YES or SSCF_UNI_ESTIND_NO. (int)
		Note that this is a local implementation parameter only.
Argument 2:	Not used.


Stack Command:	SSCF_UNI_DATA_REQ
Description:	Request that an assured SDU be sent to the SAAL peer.
Argument 1:	Pointer to an mbuf chain containing the user SDU.
		(struct mbuf *)
Argument 2:	Not used.


Stack Command:	SSCF_UNI_UNITDATA_REQ
Description:	Request that an unacknowledged SDU be sent to the SAAL peer.
Argument 1:	Pointer to an mbuf chain containing the user SDU.
		(struct mbuf *)
Argument 2:	Not used.


o The following stack commands are sent from SSCF to the signalling module:

Stack Command:	SSCF_UNI_ESTABLISH_IND
Description:	Indication that an assured SAAL connection has been established
		by the SAAL peer entity.
Argument 1:	Not used.
Argument 2:	Not used.


Stack Command:	SSCF_UNI_ESTABLISH_CNF
Description:	Confirmation of an assured SAAL connection establishment,
		previously requested via an SSCF_UNI_ESTABLISH_REQ command.
Argument 1:	Not used.
Argument 2:	Not used.


Stack Command:	SSCF_UNI_RELEASE_IND
Description:	Indication that an assured SAAL connection has been terminated
		by the SAAL peer entity.
Argument 1:	Not used.
Argument 2:	Not used.


Stack Command:	SSCF_UNI_RELEASE_CNF
Description:	Confirmation of an assured SAAL connection termination,
		previously requested via an SSCF_UNI_RELEASE_REQ command.
Argument 1:	Not used.
Argument 2:	Not used.


Stack Command:	SSCF_UNI_DATA_IND
Description:	Indication that an assured SDU has been received from the 
		SAAL peer.
Argument 1:	Pointer to an mbuf chain containing the peer's SDU.
		(struct mbuf *)
Argument 2:	Not used.


Stack Command:	SSCF_UNI_UNITDATA_IND
Description:	Indication that an unacknowledged SDU has been received from 
		the SAAL peer.
Argument 1:	Pointer to an mbuf chain containing the peer's SDU.
		(struct mbuf *)
Argument 2:	Not used.



Protocol Specifications
-----------------------
For UNI_VERS_3_0, see Q.SAAL2.
For UNI_VERS_3_1, see Q.2130.



Implementation Limitations
--------------------------
o The Parameter Data parameter is not supported for the following primitives:
	AAL-ESTABLISH request
	AAL-ESTABLISH indication
	AAL-ESTABLISH confirm
	AAL-RELEASE request
	AAL-RELEASE indication


	@(#) $Id: sscf.design,v 1.1.1.1 1996/12/04 20:48:17 mks Exp $