1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-1000645.1995(R2013) B-ISDN Signaling ATM Adaptation Layer Service Specific Coordination Function for Support of Signaling at the Network Node Interface (SSCF at the NNI) As a leading technology and solutions development organization, ATIS bring
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5、 a member of the Inter-American Telecommunication Commission (CITEL). For more information, visit. AMERICAN NATIONAL STANDARD Approval of an American National Standard requires review by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the stand
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11、writing the American National Standards Institute. Notice of Disclaimer any distribution of information associated with one AAL-connection within the AAL has tobe made based on PDU type (bottom up direction) or primitive type (top down direction); the connection is available to the AAL user as a poi
12、nt-to-point connection and providesassured information transfer based on AAL-primitives for assured information transfer.ANSI T1.645-19958ANSI T1.645-19959P o i n t - t o - p o i n t S i g n a l l i n g V i r t u a l C h a n n e l V i r t u a l P a t h A T M - S A P S S C O P S A R - s i g n a l S A
13、 R C P C S C P C S - s i g n a l A A - s i g n a l S S C F V C I C E S ( P b ) A T M - p r i m i t i v e * * C E S ( P a ) A T M - S A P S S C O P S A R - s i g n a l S A R C P C S C P C S - s i g n a l A A - s i g n a l S S C F V C I A T M - p r i m i t i v e * * A A L - p r i m i t i v e A A L - S
14、 A P M T P - S A P C E S ( P b ) * M T P - p r i m i t i v e C E S ( P b ) B - I S D N c a l l c o n t r o l n e t w o r k C E S ( P a ) C E S ( P a ) A A L - p r i m i t i v e A A L - S A P M T P - S A P * M T P - p r i m i t i v e B - I S D N c a l l c o n t r o l n e t w o r k M T P - 3 s i g n a
15、 l l i n g n e t w o r k f u n c t i o n P o i n t - t o - p o i n t S i g n a l l i n g V i r t u a l C h a n n e l V i r t u a l P a t h M A A - s i g n a l M A A L - s i g n a l M A A L - s i g n a l M A A - s i g n a l M T P - 3 s i g n a l l i n g n e t w o r k f u n c t i o n LayermanagementLa
16、yermanagementSystemmanagementSystemmanagementCES(Pb)CES(Pb)CES(Pa)CES(Pa)Figure 2 Signaling protocol stack for NNI7 Definition of the boundary between the SSCF and Layer 3 at the NNI7.1 PrimitivesThese primitives required to support the SAAL user at the NNI are shown in table 1. Their names are con-
17、sistent with the names of the messages which are exchanged between MTP level 2 and MTP level 3.ANSI T1.645-199510Table 1 Primitives between SAAL and MTP 3Type ParametersMessage Generic nameRequestIndica-tion ResponseConfirmMessageUnit FSNC BSNTCongestionParameterunit contentsAAL-MESSAGE_FOR_TRANSMIS
18、SIONX X L3 peer-peermessageAAL-RECEIVED_MESSAGEX X L3 peer-peermessageAAL-LINK_CONGESTEDX X(See note 1)AAL-LINK_CONGESTION_CEASED (See note 2)XAAL-EMERGENCY XAAL-EMERGENCY_CEASESXAAL-STOP XAAL-START XAAL-IN_SERVICE XAAL-OUT_OF_SERVICEXAAL-RETRIEVE_BSNTXAAL-RETRIEVAL_REQUEST_AND_FSNCX XAAL-RETRIEVED_
19、MESSAGESX X Message to beretrievedAAL-RETRIEVAL_COMPLETEXAAL-BSNT X XAAL-FLUSH_BUFFERS(See note 3)XAAL-CONTINUE(See note 3)XAAL-BSNT_NOT_RETRIEVABLEXNOTES 1 In North American networks, the AAL-LINK_CONGESTED primitive must indicate one of four levelsof congestion, levels 0 through 3, with 0 meaning
20、no congestion.2 The AAL-LINK_CONGESTION_CEASED primitive is not used in North American networks.3 If these primitives occur they must be ignored.ANSI T1.645-1995The primitives defined in table 1 are used as indicated in table 2.11Table 2 Use of NNI primitivesPrimitive OperationAAL-MESSAGE_FOR_TRANSM
21、ISSION Used by AAL user to send dataAAL-RECEIVED_MESSAGE Used by the AAL to deliver dataAAL-LINK_CONGESTED Indicates transmitter congestionAAL-LINK_CONGESTION_CEASED Indicates congestion has ceasedAAL-EMERGENCY Request reduction of link provingAAL-EMERGENCY_CEASES Return to normal link provingAAL-ST
22、OP Inhibits peer-to-peer communicationAAL-START Used to establish communicationsAAL-IN_SERVICE Link availableAAL-OUT_OF_SERVICE Link not usableAAL-FLUSH_BUFFERS IgnoredAAL-CONTINUE IgnoredAAL-RETRIEVE_BSNT Requests BSNT to be retrievedAAL-RETRIEVAL_REQUEST_AND_FSNC Requests non-acknowledged messages
23、 to bedeliveredAAL-RETRIEVED_MESSAGES Delivery of non-acknowledged messagesAAL-RETRIEVAL_COMPLETE Delivery of non-acknowledged messagescompletedAAL-BSNT Delivery of BSNT valueAAL-BSNT_NOT_RETRIEVABLE Notifies user that BSNT can not be retrievedNOTE In North American networks,the AAL-LINK_CONGESTED p
24、rimitive must indicate one of four levels ofcongestion, levels 0 through 3, with 0 meaning no congestion. TheAAL-LINK_CONGESTION_CEASED prim-itive is not used. 7.2 State transition diagramThe NNI-SSCF state transition diagram as seen by the SAAL user is shown in figure 3.ANSI T1.645-199512Figure 3 -
25、 NNI-SSCF state transition diagram as seen by SAAL userOut OfService1Alignment2InService3AAl_IN_SERVICE.indicationAAL-MESSAGE_FOR_TRANSMISSION.requestAAL-RECEIVED_MESSAGE.indicationAAL-LINK_CONGESTED.indicationAAL-LINK_CONGESTION_CEASED.indicationAAL-EMERGENCY.requestAAL-EMERGENCY_CEASES.requestAAL-
26、LINK_CONGESTED.indicationAAL-LINK_CONGESTION_CEASED.indicationAAL-START.requestAAL-STOP.requestAAL-OUT_OF_SERVICE.indicationAAL-STOP.requestAAL-OUT_OF_SERVICE.indicationAAL-RETRIEVE_BSNT.requestAAL-RETRIEVAL_REQUEST_AND_FSNC.requestAAL-RETRIEVED_MESSAGES.indicationAAL-RETRIEVAL_COMPLETE.indicationAA
27、L-BSNT.confirmAAL-BSNT_NOT_RETRIEVABLE.confirmAAL-EMERGENCY.requestAAL-EMERGENCY_CEASES.requestAAL-FLUSH_BUFFERS.requestAAL-CONTINUE.requestANSI T1.645-19958 Definition of the boundary between the SSCF at the NNI and the SSCOP8.1 Repertoire of signals between SSCF and SSCOPIn order to specify the SS
28、CF for the NNI, the signals between SSCF and SSCOP have to bedefined. The term “signal” is used instead of “primitive” to reflect the fact that there is no serviceaccess point defined between SSCF and SSCOP.The AA-signals between SSCF and SSCOP at the NNI are defined in table 3:The definition of the
29、se signals is as follows:a) The AA-ESTABLISH signals are used to establish a point-to-point connection for assuredinformation transfer between peer user entities;b) The AA-RELEASE signals are used to terminate a point-to-point connection for assuredinformation transfer between peer user entities;c)
30、The AA-DATA signals are used for the assured point-to-point transfer of SDUs betweenpeer user entities;d) The AA-RESYNC.indication signal notifies that the peer users invoked resynchronization ofthe SSCOP connection. This service is not supported at the NNI;e) The AA-RECOVER signals are used during
31、recovery from protocol errors;f) The AA-UNITDATA.indication signal notifies that the peer users invoked point-to-point, unas-sured transfer of SDUs between peer user entities. This service is not supported at the NNI;g) AA-RETRIEVE signals are used to retrieve SDUs submitted by the user for transmis
32、sionbut not yet released by the transmitter;h) AA-RETRIEVE_COMPLETE signal is used to indicate that there are no additional SDUs tobe returned to the SSCOP user.13Table 3 Signals between SSCF and SSCOPFunctionality Signal issued by SSCF Signal issued by SSCOPEstablishment AA-ESTABLISH.request(SSCOP-
33、UU, BR)AA-ESTABLISH.response(SSCOP-UU, BR)AA-ESTABLISH.indication(SSCOP-UU)AA-ESTABLISH.confirm(SSCOP-UU)Assured Data Transfer AA-DATA.request (MU) AA-DATA.indication (MU, SN)Release AA-RELEASE.request(SSCOP-UU)AA-RELEASE.indication(SSCOP-UU, Source)AA-RELEASE.confirm (-)Resynchronisation (See note)
34、AA-RESYNC.indication(SSCOP-UU)Data Retrieve AA-RETRIEVE.request (RN) AA-RETRIEVE.indication (MU)AA-RETRIEVE_COMPLETE.confirm (-)Error Recovery AA-RECOVER.response (-) AA-RECOVER.indication (-)Unassured Data Transfer(See note)AA-UNITDATA.indication (MU)- : The signal has no parameter.NOTE These are v
35、alid signals issued by SSCOP; however, they should never occur in practice.Table 3 Signals between SSCF and SSCOPThe parameters of the signals between SSCF and SSCOP are also defined in ANSI T1.637; ifthere is any difference between the two definitions, the one in ANSI T1.637 is definitive. The defi
36、-nition of the parameters is as follows: the Message Unit (MU) parameter is used during information transfer to convey a variable-length message. In an AA-DATA.request signal, this parameter is mapped transparently intothe Information field of an SSCOP PDU. For AA-DATA.indication and AA-UNITDATA.ind
37、icationsignals, this parameter contains the contents of the Information field of the received SSCOPPDU. The contents of the MU parameter of an AA-UNITDATA.indication are discarded. In AA-RETRIEVE.indication signals, this parameter contains a message unit returned to the SSCFfrom either the transmitt
38、er queue (data not yet sent) or the transmitter buffer. The MU is anintegral multiple of one octet; the SSCOP User-to-User Information (SSCOP-UU) parameter allows the conveyance of avariable-length user-to-user message during connection control. The SSCOP-UU is an integralmultiple of one octet, if i
39、t is present. The SSCOP-UU may be null (no data present); the Source parameter indicates to the SSCOP user whether the SSCOP layer or the peerSSCOP user originated the connection release. This parameter assumes one of the two values:“SSCOP” or “User”. If “SSCOP” is indicated, the SSCF shall discard
40、the content of the SSCOP-UU parameter, if present; the Buffer Release (BR) parameter indicates whether the transmitter may release its buffersupon release of the connection. This parameter also allows for the release of selectivelyacknowledged messages. A value of “Yes” indicates that the transmissi
41、on buffer and transmis-sion queue may be released, and a value of “No” indicates that the transmission buffer andtransmission queue shall not be released; the Sequence Number (SN) parameter indicates the value of the N(S) PDU parameter in anassociated received SD PDU which is delivered to SSCF, and
42、is used to support the dataretrieval operation; the Retrieval Number (RN) is used to support data retrieval. The value RN+1 indicates thevalue of N(S) for the first SD PDU to be retrieved. A value of “Unknown” indicates that only thenot yet transmitted SD PDUs are to be retrieved. A value of “Total”
43、 indicates that all the SDPDUs, in both the transmission buffer and the transmission queue, are to be retrieved.Since the data retrieval service can be utilized by the SAAL user at the NNI, the BR parametershall be always set to the value “No” by the SSCF at the NNI.8.2 Sequences of signals between
44、SSCF and SSCOPThe possible overall sequences of signals between SSCF and SSCOP in relation to a specificconnection are defined in the state transition diagram, figure 4. In the diagram:a) the state numbers and names correspond to SSCOP states;b) any other signal that is not shown as resulting in a t
45、ransition (from one state to the samestate, or from one state to a different state) is not permitted in that state;c) it is assumed that the signals passed between SSCOP and an SSCF are coordinated sothat collisions do not occur;d) the Idle state (state 1) reflects the absence of a connection. It is
46、 the initial and final stateof any sequence, and once it has been re-entered, the connection is released.ANSI T1.645-199514ANSI T1.645-199515AA-ESTABLISH.request AA-ESTABLISH.indicationAA-RELEASE.confirmAA-ESTABLISH.responseAA-RELEASE.indication AA-RESYNC.indicationAA-ESTABLISH.confirmAA-RELEASE.req
47、uest.OutgoingDisconnectionPending4Idle1OutgoingConnectionPending2IncomingConnectionPending3AA-ESTABLISH.request AA-RELEASE.requestIncomingResynchronizationPending6AA-RECOVER.indicationDataTransfer Ready10RecoveryPending (See note)8AA-RETRIEVE.request,AA-RETRIEVE.indication,or AA-RETRIEVE_COMPLETE.in
48、dicationAA-RETRIEVE.request,AA-RETRIEVE.indication,or AA-RETRIEVE_COMPLETE.indicationAA-RELEASE.requestAA-DATA.request or indicationAA-RECOVER.responseNOTE The SSCOP connection endpoint state Recovery Pending (state 8) covers the SSCOP statesRecovery Response Pending (state 8) and Incoming Recovery
49、Pending (state 9). Which one of theseapplies is not visible at the boundary between SSCF and SSCOP. The state Outgoing Recovery Pending(state 7) is never visible at the boundary between SSCF and SSCOP.Figure 4 State transition diagram for sequences of signals between SSCF and SSCOP9 Definition of the boundary between the SSCF and the layer managementThe signals between SSCF and layer management are defined in table 4.The signals are defined as follows:“MAAL-PROVING.indication” is used to initiate connection proving.“MAAL-STOP_PROVING.indica
