Abstract:
A mapping method, an apparatus, and a system for data transmission are provided, so as to solve a problem that mapping between a Passive Optical Network (PON) service transmission path and a Pseudo Wire (PW) and/or a Packet Switched Network (PSN) tunnel cannot be realized on a premise of ensuring Quality of Service (QoS) of data transmission. Data packets are classified according to own attribute information in PSN tunnel information and/or PW information. When Multi Protocol Label Switch (MPLS) tunnel information carried in the data packets includes the PSN tunnel information or the PW information, the data packets are classified according to Class of Service (CoS) information, and/or label information in the PSN tunnel information or the PW information; and then the classified data packets are respectively mapped to service transmission paths of different PONs. The invention is applied to a PON to support packet switching technology.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/CN2009/073806, filed on Sep. 8, 2009, which claims priority to Chinese Patent Application No. 200810222778.1, filed on Sep. 24, 2008, both of which are hereby incorporated by reference in their entireties. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of communication technology, and in particular, to a mapping method, an apparatus, and a system for data transmission. 
     BACKGROUND OF THE INVENTION 
     Passive Optical Network (PON), as a bandwidth optical access technology, employs a point-to-multipoint topological structure, and as shown in  FIG. 1 , the PON includes an Optical Network Terminal (OLT), a passive Optical Distribution Network (ODN), and an Optical Network Unit (ONU). The OLT provides a network side interface, and is connected to at least one ODN; the ONU provides a user side interface, and is connected to an ODN; and the ODN transmits downlink data of the OLT to each ONU through optical distribution, and transmits uplink data of ONU to the OLT through convergence. 
     Ethernet Passive Optical Network (EPON) and Gigabit Passive Optical Network (GPON) are two newest PON technologies. 
     In the EPON, the OLT directly allocates a transmission time window to an ONU; and an identifier of a service transmission path allocated by the OLT to the ONU is called as a Logical Link Identifier (LLID). 
     In the GPON, the service transmission path is called as a GPON Encapsulation Method PORT (GEM PORT); and the ONU supports at least one Transmission Container (T-CONT), and the T-CONT supports at least one GEM PORT. 
     A Packet Switch Network (PSN) tunnel is a data transfer path formed by spanning a PSN from a Provider Edge (PE) to an opposite PE. A Pseudo Wire (PW) is a kind of PSN tunnel. Multiple PWs may be multiplexed in one PSN tunnel. As shown in  FIG. 2 , two PEs being PE 1  and PE 2  provide at least one PW for Customer Edges (CEs) being CE 1  and CE 2  connected thereto, to enable the corresponding CEs to communicate with each other on the PSN. PE 1  encapsulates a local data unit sent from CE 1  into a PW Protocol Data Unit (PW-PDU), and transfers the PW-PDU to PE 2  through the PSN tunnel; and PE 2  decapsulates the received PW-PDU, to obtain the local data unit; and sends the local data unit to CE 2 . 
     At present, the PSN tunnel and the PW are generally encapsulated in a Multi Protocol Label Switch (MPLS) encapsulation mode. 
     MPLS message is 32 Bit, in which 20 Bit is used as MPLS label information, in which the MPLS label information is configured to identify a path forwarding destination address; and another 3 Bit in the message is generally used as Class of Service (CoS) information, in which the CoS information is configured to identify CoS of forwarded data packets. 
     In the implementation of the present invention, the inventor finds that the prior art at least has the following problems. When a network employs both a PON mode and a PSN mode, the data transmission path is not only a PON service transmission path, but also a PW and/or a PSN tunnel. All the PON service transmission path, the PW, and/or the PSN tunnel provide different Quality of Services (QoSs) for data transmission; however, in the prior art, mapping between the PON service transmission path and the PW and/or the PSN tunnel cannot be realized on a premise of ensuring QoS of data transmission. 
     SUMMARY OF THE INVENTION 
     In an aspect, the present invention is directed to a mapping method for data transmission, so as to ensure QoS of data transmission after mapping between a PON service transmission path and a PW and/or a PSN tunnel. 
     In order to achieve the above objective, the present invention employs the following technical solution. 
     A mapping method for data transmission is provided, where the method includes: 
     receiving a service stream, in which the service stream includes at least two data packets; 
     acquiring MPLS tunnel information in the data packets, in which the MPLS tunnel information includes own attribute information, CoS information, and/or label information in PSN tunnel information and/or PW information; and 
     classifying the data packets according to the MPLS tunnel information, and mapping the classified data packets respectively to service transmission paths of different PONs. 
     In an aspect, the present invention is directed to a mapping apparatus for data transmission, so as to ensure QoS of data transmission after mapping between a PON service transmission path and a PW and/or a PSN tunnel. 
     In order to achieve the above objective, the present invention employs the following technical solution. 
     A mapping apparatus for data transmission is provided, where the apparatus includes: 
     a service interface unit, configured to receive a service stream, in which the service stream includes at least two data packets; 
     a tunnel information unit, configured to acquire MPLS tunnel information in the data packets, in which the MPLS tunnel information includes own attribute information, CoS information, and/or label information in PSN tunnel information and/or PW information; 
     a QoS mapping unit, configured to classify the data packets according to the MPLS tunnel information, and map the classified data packets respectively to service transmission paths of different PONs; and 
     a PON sending unit, configured to send the data packets through the service transmission paths to which the data packets are mapped. 
     In an aspect, the present invention is directed to a mapping system for data transmission, so as to ensure QoS of data transmission after mapping between a PON service transmission path and a PW and/or a PSN tunnel. 
     In order to achieve the above objective, the present invention employs the following technical solution. 
     A mapping system for data transmission is provided, which includes an ONU and an OLT, in which the ONU and the OLT have at least one service transmission path. 
     The ONU receives a service stream including at least two data packets, and acquires MPLS tunnel information in the data packets; and classifies the data packets according to the MPLS tunnel information, maps the classified data packets respectively to service transmission paths of different PONs, and sends the data packets to the OLT. 
     Alternatively, the OLT receives a service stream including at least two data packets, acquires MPLS tunnel information in the data packets; and classifies the data packets according to the MPLS tunnel information, maps the classified data packets respectively to service transmission paths of different PONs, and sends the data packets to the ONU. 
     The MPLS tunnel information includes own attribute information, CoS information, and/or label information in PSN tunnel information and/or PW information. 
     According to the mapping method, the apparatus, and the system for data transmission according to the present invention, data packets are respectively mapped to service transmission paths of different PONs according to MPLS tunnel information, so as to solve a problem that mapping between a PON service transmission path and a PW and/or a PSN tunnel cannot be realized on a premise of ensuring QoS of data transmission, such that the QoS of the data transmission is ensured after mapping between the PON service transmission path and the PW and/or the PSN tunnel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       To illustrate the technical solutions according to the embodiments of the present invention or in the prior art more clearly, the accompanying drawings for describing the embodiments or the prior art are introduced briefly in the following. Apparently, the accompanying drawings in the following description are only some embodiments of the present invention, and persons of ordinary skill in the art can derive other drawings from the accompanying drawings without creative efforts. 
         FIG. 1  is a network architecture diagram of a PON in the prior art; 
         FIG. 2  is a diagram of a reference model of a Pseudo-Wire Emulation Edge to Edge (PWE3) network in the prior art; 
         FIG. 3  is a schematic view of a mapping method for data transmission according to an embodiment of the present invention; 
         FIG. 4  is a schematic view of another mapping method for data transmission according to an embodiment of the present invention; 
         FIG. 5  is a structural view of a mapping apparatus for data transmission according to an embodiment of the present invention; 
         FIG. 6  is a structural view of an OLT for data transmission according to an embodiment of the present invention; 
         FIG. 7  is a structural view of an ONU for data transmission according to an embodiment of the present invention; 
         FIG. 8  is a structural view of a mapping system for data transmission according to an embodiment of the present invention; 
         FIG. 9(   a ) is a principle diagram of mapping data packets of the same PSN tunnels and the same PWs by an ONU or an OLT to a same GEM PORT in an embodiment of the present invention; (b) is a principle diagram of mapping data packets of all PWs of same PSN tunnel by an ONU or an OLT to the same GEM PORT in case that one user is corresponding to one external layer PSN tunnel, in an embodiment of the present invention; and (c) is a principle diagram of mapping data packets of all PWs of same PSN tunnel by an ONU or an OLT to the same GEM PORT in case that one user is corresponding to multiple external layer PSN tunnels, in an embodiment of the present invention; and 
         FIG. 10(   a ) is a principle diagram of mapping data packets of the same CoS and the same label by an ONU or an OLT to the same GEM PORT in case that one user is corresponding to one MPLS label, in an embodiment of the present invention; (b) is a principle diagram of mapping data packets of the same CoS and the same label by an ONU or an OLT to the same GEM PORT in case that one user is corresponding to one CoS, in an embodiment of the present invention; (c) is a principle diagram of mapping data packets of all CoSs having the same label by an ONU or an OLT to the same GEM PORT in case that one user is corresponding to one MPLS label, in an embodiment of the present invention; (d) is a principle diagram of mapping data packets of all CoSs having the same label by an ONU or an OLT to the same GEM PORT in case that one user is corresponding to one CoS, in an embodiment of the present invention; (e) is a principle diagram of mapping data packets of all labels having the same label by an ONU or an OLT to the same GEM PORT in case that one user is corresponding to one MPLS label, in an embodiment of the present invention; and (f) is a principle diagram of mapping data packets of all labels having the same label by an ONU or an OLT to the same GEM PORT in case that one user is corresponding to one CoS, in an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The technical solution of the present invention will be clearly and completely described in the following with reference to the accompanying drawings. It is obvious that the embodiments to be described are only a part rather than all of the embodiments of the present invention. All other embodiments acquired by persons skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. 
     In order to ensure QoS of data transmission after mapping between a PON service transmission path and a PW and/or a PSN tunnel, in an embodiment, the present invention provides a mapping method for data transmission. Hereinafter, the mapping method for data transmission is described respectively in an uplink direction and a downlink direction. 
     As shown in  FIG. 3 , in the uplink direction, the mapping method for data transmission according to the embodiment of the present invention includes the following steps. 
     In Step  301 , an ONU receives a service stream, in which the service stream includes at least two data packets. 
     In an uplink direction from the ONU to an OLT, the ONU receives a service stream transferred from a user side, in which the service stream includes at least two data packets. 
     In Step  302 , the ONU acquires MPLS tunnel information in the data packets, in which the MPLS tunnel information includes own attribute information, CoS information, and/or label information in PSN tunnel information and/or PW information. 
     In the uplink direction from the ONU to the OLT, the data packets received by the ONU do not carry MPLS tunnel information; and thus the ONU adds the MPLS tunnel information to the data packets. The MPLS tunnel information includes own attribute information, CoS information, and/or label information in PSN tunnel information and/or PW information; and the own attribute information in the PSN tunnel information and/or the PW information includes attribute identifiers that distinguish different PSN tunnel information and/or PW information. 
     In Step  303 , the ONU classifies the data packets according to the MPLS tunnel information, and maps the classified data packets respectively to service transmission paths of different PONs. 
     The MPLS tunnel information includes the PSN tunnel information and/or the PW information; the PSN tunnel information includes the own attribute information; and the PW information includes the own attribute information. The ONU can distinguish PSN tunnels or PWs according to the own attribute information in the PSN tunnel information and/or the PW information. The ONU classifies the data packets according to the own attribute information, and maps the classified data packets respectively to service transmission paths of different PONs, through methods including the following. 
     1. The ONU classifies data packets having the same own attribute information in the PSN tunnel information and the same own attribute information in the PW information into one type according to the own attribute information in the PSN tunnel information and the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of the same PSN tunnel and the same PW are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIG. 9(   a ), in case that a user  11  is corresponding to PSN tunnel  1 , and a user  12  is corresponding to PSN tunnel  2 , the ONU maps data packets of PSN tunnel  1  and PW 101  to GEM PORT 11  for transmission, maps data packets of PSN tunnel  1 , and PW 102  to GEM PORT 12  for transmission, . . . , and maps data packets of PSN tunnel  2  and PW 102  to GEM PORT 15  for transmission. 
     2. The ONU classifies data packets having the same own attribute information in the PSN tunnel information into one type according to the own attribute information in the PSN tunnel information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all PWs of the same PSN tunnel are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIGS. 9(   b ) and ( c ), in  FIG. 9(   b ), in case that the user  11  is corresponding to PSN tunnel  1 , and the user  12  is corresponding to PSN tunnel  2 , the ONU maps data packets of all PWs (PW 101 , PW 102 , and PW 103 ) of PSN tunnel  1  to GEM PORT 11  for transmission, and maps data packets of all PWs (PW 101  and PW 102 ) of PSN tunnel  2  to GEM PORT 12  for transmission. In  FIG. 9(   c ), in case that the user  11  is corresponding to PW 101 , and the user  12  is corresponding to PW 102 , the ONU maps data packets of all PWs (PW 101  and PW 102 ) of PSN tunnel  1  to GEM PORT 12  for transmission, maps data packets of all PWs (PW 101  and PW 102 ) of PSN tunnel  2  to GEM PORT 13  for transmission, and maps data packets of all PWs (PW 101 ) of PSN tunnel  3  to GEM PORT 11  for transmission. 
     In the embodiment of the present invention, after receiving the data packets, the ONU adds the PSN tunnel information and/or the PW information to the data packets; and classifies the data packets according to the own attribute information in the PSN tunnel information and/or the PW information, and maps the data packets of the same type to a service transmission path of the same PON. Different PWs and/or PSN tunnels provide different QoSs for data transmission, and classification and mapping are performed according to the own attribute information in the PSN tunnel information and/or the PW information, so as to achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on a premise of ensuring QoS of data transmission. 
     In addition, the PSN tunnel information further includes CoS information and label information; and the PW information further includes CoS information and label information. 
     The ONU may further classify the data packets according to the CoS information and/or the label information in the PSN tunnel information or the PW information, and map the classified data packets respectively to service transmission paths of different PONs, through methods including the following. 
     A. The ONU classifies data packets having the same CoS information and the same label information into one type according to the CoS information and the label information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets having the same CoS and the same label are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIGS. 10(   a ) and ( b ), in  FIG. 10(   a ), in case that a user  11  is corresponding to MPLS label  101 , and a user  12  is corresponding to MPLS label  102 , the ONU maps data packets of CoS 1  and MPLS label  101  to GEM PORT 11  for transmission, maps data packets of CoS 2  and MPLS label  101  to GEM PORT 12  for transmission, . . . , and maps data packets of CoS 2  and MPLS label  102  to GEM PORT 15  for transmission. In  FIG. 10(   b ), in case that the user  11  is corresponding to CoS 1 , and the user  12  is corresponding to CoS 2 , the ONU maps data packets of CoS 1  and MPLS label  101  to GEM PORT 11  for transmission, maps data packets of CoS 1  and MPLS label  102  to GEM PORT 12  for transmission, . . . , and maps data packets of CoS 2  and MPLS label  102  to GEM PORT 15  for transmission. 
     B. The ONU classifies data packets having the same label information into one type, according to the label information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all CoSs having the same label are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIGS. 10(   c ) and ( d ), in  FIG. 10(   c ), in case that the user  11  is corresponding to MPLS label  101 , and the user  12  is corresponding to MPLS label  102 , the ONU maps data packets of all CoSs (CoS 1 , CoS 2 , and CoS 3 ) having MPLS label  101  to GEM PORT 11  for transmission, and maps data packets of all CoSs (CoS 1  and CoS 2 ) having MPLS label  102  to GEM PORT 12  for transmission. In  FIG. 10(   d ), in case that the user  11  is corresponding to CoS 1 , and the user  12  is corresponding to CoS 2 , the ONU maps data packets of all CoSs (CoS 1  and CoS 2 ) having MPLS label  101  to GEM PORT 12  for transmission, maps data packets of all CoSs (CoS 1  and CoS 2 ) having MPLS label  102  to GEM PORT 13  for transmission, and maps data packets of all CoSs (CoS 1 ) having MPLS label  103  to GEM PORT 11  for transmission. 
     C. The ONU classifies data packets having the same CoS information into one type according to the CoS information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all labels having the same CoS are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIGS. 10(   e ) and ( f ), in  FIG. 10(   e ), in case that the user  11  is corresponding to MPLS label  101 , and the user  12  is corresponding to MPLS label  102 , the ONU maps data packets with all MPLS labels (label  101  and label  102 ) of CoS 1  to GEM PORT 12  for transmission, maps data packets with all MPLS labels (label  101  and label  102 ) of CoS 2  to GEM PORT 13  for transmission, and maps data packets with all MPLS labels (label  101 ) of CoS 3  to GEM PORT 11  for transmission. In  FIG. 10(   f ), in case that the user  11  is corresponding to CoS 1 , and the user  12  is corresponding to CoS 2 , the ONU maps data packets with all MPLS labels (label  101 , label  102 , and label  103 ) of CoS 1  to GEM PORT 11  for transmission, and maps data packets with all MPLS labels (label  101  and label  102 ) of CoS 2  to GEM PORT 12  for transmission. 
     In addition, when the PON is a GPON, the ONU further needs to map the GEM PORT to a T-CONT in one of the following manners. 
     1. Different GEM PORTs are respectively mapped to different T-CONTs at 1:1. 
     2. Different GEM PORTs are mapped to different T-CONTs at N:1. 
     3. The ONU maps GEM PORTs of the same CoS to the same T-CONT according to the CoS information in the PSN tunnel information or the PW information. 
     In the embodiment of the present invention, the ONU may further classify the data packets according to the CoS information and/or the label information in the PSN tunnel information or the PW information, and maps the data packets of the same type to the service transmission path of the same PON. The CoS information and/or the label information in the PSN tunnel information or the PW information further identifies transmission QoS requirements of the data packets in detail, and classification and mapping are performed according to the CoS information and/or the label information in the PSN tunnel information or the PW information, so as to further achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on the premise of ensuring QoS of data transmission. 
     As shown in  FIG. 4 , in the downlink direction, the mapping method for data transmission according to the embodiment of the present invention includes the following steps. 
     In Step  401 , an OLT receives a service stream, in which the service stream includes at least two data packets. 
     In an uplink direction from the OLT to an ONU, the OLT receives a service stream transferred from a network side, in which the service stream includes at least two data packets. 
     In Step  402 , the OLT acquires MPLS tunnel information in the data packets, in which the MPLS tunnel information includes own attribute information, CoS information, and/or label information in PSN tunnel information and/or PW information. 
     In the downlink direction from the OLT to the ONU, the data packets received by the OLT carry MPLS tunnel information; and the OLT switches the MPLS tunnel information carried in the data packets. The MPLS tunnel information includes own attribute information, CoS information, and/or label information in PSN tunnel information and/or PW information; and the own attribute information in the PSN tunnel information and/or the PW information includes attribute identifiers that distinguish different PSN tunnel information and/or PW information. 
     In Step  403 , the OLT classifies the data packets according to the MPLS tunnel information, and maps the classified data packets respectively to service transmission paths of different PONs. 
     The MPLS tunnel information includes the PSN tunnel information and/or the PW information; the PSN tunnel information includes the own attribute information; and the PW information includes the own attribute information. The OLT can distinguish PSN tunnels or PWs according to the own attribute information in the PSN tunnel information and/or the PW information. The OLT classifies the data packets according to the own attribute information, and maps the classified data packets respectively to service transmission paths of different PONs, through methods including the following. 
     1. The OLT classifies data packets having the same own attribute information in the PSN tunnel information and the same own attribute information in the PW information into one type according to the own attribute information in the PSN tunnel information and the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of the same PSN tunnel and the same PW are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIG. 9(   a ), in case that a user  11  is corresponding to PSN tunnel  1 , and a user  12  is corresponding to PSN tunnel  2 , the OLT maps data packets of PSN tunnel  1  and PW 101  to GEM PORT 11  for transmission, maps data packets of PSN tunnel  1  and PW 102  to GEM PORT 12  for transmission, . . . , and maps data packets of PSN tunnel  2  and PW 102  to GEM PORT 15  for transmission. 
     2. The OLT classifies data packets having the same own attribute information in the PSN tunnel information into one type according to the own attribute information in the PSN tunnel information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all PWs of the same PSN tunnel are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIGS. 9(   b ) and ( c ), in  FIG. 9(   b ), in case that the user  11  is corresponding to PSN tunnel  1 , and the user  12  is corresponding to PSN tunnel  2 , the OLT maps data packets of all PWs (PW 101 , PW 102 , and PW 103 ) of PSN tunnel  1  to GEM PORT 11  for transmission, and maps data packets of all PWs (PW 101  and PW 102 ) of PSN tunnel  2  to GEM PORT 12  for transmission. In  FIG. 9(   c ), in case that the user  11  is corresponding to PW 101 , and the user  12  is corresponding to PW 102 , the OLT maps data packets of all PWs (PW 101  and PW 102 ) of PSN tunnel  1  to GEM PORT 12  for transmission, maps data packets of all PWs (PW 101  and PW 102 ) of PSN tunnel  2  to GEM PORT 13  for transmission, and maps data packets of all PWs (PW 101 ) of PSN tunnel  3  to GEM PORT 11  for transmission. In the embodiment of the present invention, after receiving the data packets, the OLT switches the PSN tunnel information and/or the PW information carried in the data packets; and classifies the data packets according to the own attribute information in the PSN tunnel information and/or the PW information, and maps the data packets of the same type to a service transmission path of the same PON. Different PWs and/or PSN tunnels provide different QoSs for data transmission, and classification and mapping are performed according to the own attribute information in the PSN tunnel information and/or the PW information, so as to achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on the premise of ensuring QoS of data transmission. 
     In addition, the PSN tunnel information further includes CoS information and label information; and the PW information further includes CoS information and label information. 
     The OLT may further classify the data packets according to the CoS information and/or the label information in the PSN tunnel information or the PW information, and map the classified data packets respectively to service transmission paths of different PONs, through methods including the following. 
     A. The OLT classifies data packets having the same CoS information and the same label information into one type according to the CoS information and the label information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets having the same CoS and the same label are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIGS. 10(   a ) and ( b ), in  FIG. 10(   a ), in case that a user  11  is corresponding to MPLS label  101 , and a user  12  is corresponding to MPLS label  102 , the OLT maps data packets of CoS 1  and MPLS label  101  to GEM PORT 11  for transmission, maps data packets of CoS 2  and MPLS label  101  to GEM PORT 12  for transmission, . . . , and maps data packets of CoS 2  and MPLS label  102  to GEM PORT 15  for transmission. In  FIG. 10(   b ), in case that the user  11  is corresponding to CoS 1 , and the user  12  is corresponding to CoS 2 , the OLT maps data packets of CoS 1  and MPLS label  101  to GEM PORT 11  for transmission, maps data packets of CoS 1  and MPLS label  102  to GEM PORT 12  for transmission, . . . , and maps data packets of CoS 2  and MPLS label  102  to GEM PORT 15  for transmission. 
     B. The OLT classifies data packets having the same label information into one type, according to the label information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all CoSs having the same label are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIGS. 10(   c ) and ( d ), in  FIG. 10(   c ), in case that the user  11  is corresponding to MPLS label  101 , and the user  12  is corresponding to MPLS label  102 , the OLT maps data packets of all CoSs (CoS 1 , CoS 2 , and CoS 3 ) having MPLS label  101  to GEM PORT 11  for transmission, and maps data packets of all CoSs (CoS 1  and CoS 2 ) having MPLS label  102  to GEM PORT 12  for transmission. In  FIG. 10(   d ), in case that the user  11  is corresponding to CoS 1 , and the user  12  is corresponding to CoS 2 , the OLT maps data packets of all CoSs (CoS 1  and CoS 2 ) having MPLS label  101  to GEM PORT 12  for transmission, maps data packets of all CoSs (CoS 1  and CoS 2 ) having MPLS label  102  to GEM PORT 13  for transmission, and maps data packets of all CoSs (CoS 1 ) having MPLS label  103  to GEM PORT 11  for transmission. 
     C. The OLT classifies data packets having the same CoS information into one type according to the CoS information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all labels having the same CoS are classified into one type, and mapped to the same GEM PORT/LLID. 
     For example, as shown in  FIGS. 10(   e ) and ( f ), in  FIG. 10(   e ), in case that the user  11  is corresponding to MPLS label  101 , and the user  12  is corresponding to MPLS label  102 , the OLT maps data packets with all MPLS labels (label  101  and label  102 ) of CoS 1  to GEM PORT 12  for transmission, maps data packets with all MPLS labels (label  101  and label  102 ) of CoS 2  to GEM PORT 13  for transmission, and maps data packets with all MPLS labels (label  101 ) of CoS 3  to GEM PORT 11  for transmission. In  FIG. 10(   f ), in case that the user  11  is corresponding to CoS 1 , and the user  12  is corresponding to CoS 2 , the OLT maps data packets with all MPLS labels (label  101 , label  102 , and label  103 ) of CoS 1  to GEM PORT 11  for transmission, and maps data packets with all MPLS labels (label  101  and label  102 ) of CoS 2  to GEM PORT 12  for transmission. 
     In the embodiment of the present invention, the OLT may further classify the data packets according to the CoS information and/or the label information in the PSN tunnel information or the PW information, and maps the data packets of the same type to the service transmission path of the same PON. The CoS information and/or the label information in the PSN tunnel information or the PW information further identifies transmission QoS requirements of the data packets in detail, and classification and mapping are performed according to the CoS information and/or the label information in the PSN tunnel information or the PW information, so as to further achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on the premise of ensuring QoS of data transmission. 
     In order to ensure QoS of data transmission after mapping between a PON service transmission path and a PW and/or a PSN tunnel, in an embodiment, the present invention provides a mapping apparatus for data transmission. As shown in  FIG. 5 , the mapping apparatus for data transmission according to the embodiment of the present invention includes a QoS mapping unit  503 . 
     The QoS mapping unit  503  is configured to classify data packets according to MPLS tunnel information, and map the classified data packets respectively to service transmission paths of different PONs. 
     The MPLS tunnel information includes PSN tunnel information and/or PW information; the PSN tunnel information includes own attribute information; and the PW information includes own attribute information. The own attribute information in the PSN tunnel information and/or the PW information includes attribute identifiers that distinguish different PSN tunnel information and/or PW information. 
     The QoS mapping unit  503  classifies the data packets according to the own attribute information in the PSN tunnel information and/or the PW information, and maps the classified data packets respectively to service transmission paths of different PONs. 
     In addition, the PSN tunnel information further includes CoS information and label information; and the PW information further includes CoS information and label information. The QoS mapping unit  503  maps the data packets respectively to service transmission paths of different PONs according to the CoS information and/or the label information in the PSN tunnel information or the PW information. 
     Before the classifying and the mapping, the mapping apparatus for data transmission according to the embodiment of the present invention further needs to receive the data packets, and acquire the MPLS tunnel information in the data packets; and further needs to send the data packets after classifying and the mapping. Therefore, the mapping apparatus for data transmission according to the embodiment of the present invention further includes a service interface unit  501 , a tunnel information unit  502 , and a PON sending unit  504 . 
     The service interface unit  501  is configured to receive a service stream, in which the service stream includes at least two data packets. 
     The tunnel information unit  502  is configured to acquire the MPLS tunnel information in the data packets, in which the MPLS tunnel information includes the own attribute information, the CoS information, and/or the label information in the PSN tunnel information and/or the PW information. 
     The PON sending unit  504  is configured to send the data packets through the service transmission paths to which the data packets are mapped. 
     In the embodiment of the present invention, the QoS mapping unit  503  maps the data packets respectively to the service transmission paths of different PONs, according to the MPLS tunnel information, so as to achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on the premise of ensuring QoS of data transmission. The mapping apparatus for data transmission includes an OLT or an ONU. Hereinafter, a specific embodiment of the mapping apparatus for data transmission is described respectively with the OLT and the ONU as examples. 
     As shown in  FIG. 6 , the OLT for data transmission according to an embodiment of the present invention includes a QoS mapping unit  603 . 
     The QoS mapping unit  603  is configured to classify data packets according to MPLS tunnel information, and map the classified data packets respectively to service transmission paths of different PONs. 
     The MPLS tunnel information includes PSN tunnel information and/or PW information; the PSN tunnel information includes own attribute information; and the PW information includes own attribute information. The own attribute information in the PSN tunnel information and/or the PW information includes attribute identifiers that distinguish different PSN tunnel information and/or PW information. 
     The QoS mapping unit  603  classifies the data packets according to the own attribute information in the PSN tunnel information and/or the PW information, and maps the classified data packets respectively to service transmission paths of different PONs, through methods including the following. 
     1. The QoS mapping unit  603  classifies data packets having the same own attribute information in the PSN tunnel information and the same own attribute information in the PW information into one type according to the own attribute information in the PSN tunnel information and the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of the same PSN tunnel and the same PW are classified into one type, and mapped to the same GEM PORT/LLID. 
     2. The QoS mapping unit  603  classifies data packets having the same own attribute information in the PSN tunnel information into one type according to the own attribute information in the PSN tunnel information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all PWs of the same PSN tunnel are classified into one type, and mapped to the same GEM PORT/LLID. 
     In the embodiment of the present invention, the QoS mapping unit  603  classifies the data packets according to the own attribute information in the PSN tunnel information and/or the PW information, and maps the data packets of the same type to a service transmission path of the same PON. Different PWs and/or PSN tunnels provide different QoSs for data transmission, and classification and mapping are performed according to the own attribute information in the PSN tunnel information and/or the PW information, so as to achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on the premise of ensuring QoS of data transmission. 
     In addition, the PSN tunnel information further includes CoS information and label information; and the PW information further includes CoS information and label information. The QoS mapping unit  603  may further classify the data packets according to the CoS information and/or the label information in the PSN tunnel information or the PW information, and map the classified data packets respectively to service transmission paths of different PONs, through methods including the following. 
     A. The QoS mapping unit  603  classifies data packets having the same CoS information and the same label information into one type according to the CoS information and the label information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets having the same CoS, and the same label are classified into one type, and mapped to the same GEM PORT/LLID. 
     B. The QoS mapping unit  603  classifies data packets having the same label information into one type, according to the label information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all CoSs having the same label are classified into one type, and mapped to the same GEM PORT/LLID. 
     C. The QoS mapping unit  603  classifies data packets having the same CoS information into one type according to the CoS information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all labels having the same CoS are classified into one type, and mapped to the same GEM PORT/LLID. 
     In the embodiment of the present invention, the QoS mapping unit  603  may further classify the data packets according to the CoS information and/or the label information in the PSN tunnel information or the PW information, and maps the data packets of the same type to the service transmission path of the same PON. The CoS information and/or the label information in the PSN tunnel information or the PW information further identifies transmission QoS requirements of the data packets in detail, and classification and mapping are performed according to the CoS information and/or the label information in the PSN tunnel information or the PW information, so as to further achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on the premise of ensuring QoS of data transmission. 
     Before the classifying and the mapping, the OLT for data transmission according to the embodiment of the present invention further needs to receive the data packets, and acquire the MPLS tunnel information in the data packets; and further needs to send the data packets after the classifying and the mapping. Therefore, the OLT for data transmission according to the embodiment of the present invention further includes a service interface unit  601 , a tunnel information unit  602 , and a PON sending unit  604 . 
     The service interface unit  601  is configured to receive a service stream, in which the service stream includes at least two data packets. 
     The tunnel information unit  602  is configured to switch M PLS tunnel information carried in the data packets, in which the MPLS tunnel information includes the own attribute information, the CoS information, and/or the label information in the PSN tunnel information and/or the PW information. 
     The PON sending unit  604  is configured to send the data packets through the service transmission paths to which the data packets are mapped. 
     In the embodiment of the present invention, the QoS mapping unit  603  only classifies and maps the data packets in a downlink direction. Hereinafter, a process for forwarding downlink data by an OLT is described in detail, which includes the following steps. 
     The service interface unit  601  receives a service stream from a network side, in which the service stream includes at least two data packets; the tunnel information unit  602  switches MPLS tunnel information carried in the data packets; the QoS mapping unit  603  maps the data packets respectively to GEM PORT/LLIDs of different PONs according to the MPLS tunnel information processed by the tunnel information unit  602 , following the methods as described above; and the PON sending unit  604  sends the data packets through the GEM PORT/LLIDs to which the data packets are mapped. 
     As shown in  FIG. 7 , the ONU for data transmission according to an embodiment of the present invention includes a QoS mapping unit  703 . 
     The QoS mapping unit  703  is configured to classify data packets according to MPLS tunnel information, and map the classified data packets respectively to service transmission paths of different PONs. 
     The MPLS tunnel information includes PSN tunnel information and/or PW information; and the PSN tunnel information includes own attribute information; and the PW information includes own attribute information. The own attribute information in the PSN tunnel information and/or the PW information includes attribute identifiers that distinguish different PSN tunnel information and/or PW information. 
     The QoS mapping unit  703  classifies the data packets according to the own attribute information in the PSN tunnel information and/or the PW information, and maps the classified data packets respectively to service transmission paths of different PONs, through methods including the following. 
     1. The QoS mapping unit  703  classifies data packets having the same own attribute information in the PSN tunnel information and the same own attribute information in the PW information into one type according to the own attribute information in the PSN tunnel information and the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of the same PSN tunnel and the same PW are classified into one type, and mapped to the same GEM PORT/LLID. 
     2. The QoS mapping unit  703  classifies data packets having the same own attribute information in the PSN tunnel information into one type according to the own attribute information in the PSN tunnel information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all PWs of the same PSN tunnel are classified into one type, and mapped to the same GEM PORT/LLID. 
     In the embodiment of the present invention, the QoS mapping unit  703  classifies the data packets according to the own attribute information in the PSN tunnel information and/or the PW information, and maps the data packets of the same type to a service transmission path of the same PON. Different PWs and/or PSN tunnels provide different QoSs for data transmission, and classification and mapping are performed according to the own attribute information in the PSN tunnel information and/or the PW information, so as to achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on the premise of ensuring QoS of data transmission. 
     In addition, the PSN tunnel information further includes CoS information and label information; and the PW information further includes CoS information and label information. The QoS mapping unit  703  may further classify the data packets according to the CoS information and/or the label information in the PSN tunnel information or the PW information, and map the classified data packets respectively to service transmission paths of different PONs, through methods including the following. 
     A. The QoS mapping unit  703  classifies data packets having the same CoS information and the same label information into one type according to the CoS information and the label information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets having the same CoS and the same label are classified into one type, and mapped to the same GEM PORT/LLID. 
     B. The QoS mapping unit  703  classifies data packets having the same label information into one type, according to the label information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all CoSs having the same label are classified into one type, and mapped to the same GEM PORT/LLID. 
     C. The QoS mapping unit  703  classifies data packets having the same CoS information into one type according to the CoS information in the PSN tunnel information or the PW information, and maps the data packets classified into the same type to a service transmission path of the same PON. That is to say, the data packets of all labels having the same CoS are classified into one type, and mapped to the same GEM PORT/LLID. 
     In addition, when the PON is a GPON, the QoS mapping unit  703  further needs to map the GEM PORT to a T-CONT in one of the following manners. 
     1. Different GEM PORTs are respectively mapped to different T-CONTs at 1:1. 
     2. Different GEM PORTs are mapped to different T-CONTs at N:1. 
     3. The QoS mapping unit  703  maps GEM PORTs of the same CoS information to the same T-CONT according to the CoS information in the PSN tunnel information or the PW information. 
     In the embodiment of the present invention, the QoS mapping unit  703  may further classify the data packets according to the CoS information and/or the label information in the PSN tunnel information or the PW information, and map the data packets of the same type to the service transmission path of the same PON. The CoS information and/or the label information in the PSN tunnel information or the PW information further identifies transmission QoS requirements of the data packets in detail, and classification and mapping are performed according to the CoS information and/or the label information in the PSN tunnel information or the PW information, so as to further achieve mapping between a PON service transmission path and a PW and/or a PSN tunnel on the premise of ensuring QoS of data transmission. 
     Before the classifying and the mapping, the ONU for data transmission according to the embodiment of the present invention further needs to receive the data packets, and acquire the MPLS tunnel information in the data packets; and further needs to send the data packets after the classifying and the mapping. Therefore, the ONU for data transmission according to the embodiment of the present invention further includes a service interface unit  701 , a tunnel information unit  702 , and a PON sending unit  704 . 
     The service interface unit  701  is configured to receive a service stream, in which the service stream includes at least two data packets. 
     The tunnel information unit  702  is configured to add MPLS tunnel information to the data packets, in which the MPLS tunnel information includes the own attribute information, the CoS information, and/or the label information in the PSN tunnel information and/or the PW information. 
     The PON sending unit  704  is configured to send the data packets through the service transmission paths to which the data packets are mapped. 
     In the embodiment of the present invention, the QoS mapping unit  703  only classifies and maps the data packets in an uplink direction. Hereinafter, a process for forwarding downlink data by an ONU is described in detail. The process for forwarding uplink data by the ONU includes the following steps. 
     The service interface unit  701  receives a service stream from a user side, in which the service stream includes at least two data packets; the tunnel information unit  702  adds MPLS tunnel information to the data packets; the QoS mapping unit  703  maps the data packets respectively to GEM PORT/LLIDs of different PONs according to the MPLS tunnel information processed by the tunnel information unit  702 , following the methods as described above; and the PON sending unit  704  sends the data packets through the GEM PORT/LLIDs to which the data packets are mapped. 
     In order to ensure QoS of data transmission after mapping between a PON service transmission path and a PW and/or a PSN tunnel, in an embodiment, the present invention provides a mapping system for data transmission. As shown in  FIG. 8 , the mapping system for data transmission according to the embodiment of the present invention includes an ONU  801  and an OLT  802 , in which the ONU  801  and the OLT  802  have at least one service transmission path. 
     The ONU  801  receives a service stream including at least two data packets, and acquires MPLS tunnel information in the data packets; and classifies the data packets according to the MPLS tunnel information, maps the classified data packets respectively to service transmission paths of different PONs, and sends the data packets to the OLT  802 . 
     Alternatively, the OLT  802  receives a service stream including at least two data packets, and acquires MPLS tunnel information in the data packets; and classifies the data packets according to the MPLS tunnel information, maps the classified data packets respectively to service transmission paths of different PONs, and sends the data packets to the ONU  801 . 
     The MPLS tunnel information includes own attribute information, CoS information, and/or label information in PSN tunnel information and/or PW information. 
     Those of ordinary skill in the art should understand that all or a part of the steps of the method according to the embodiments of the present invention may be implemented by a program instructing relevant hardware. The program may be stored in a computer readable storage medium. When the program is run, the steps of the method according to the embodiments of the present invention are performed. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), and a Random Access Memory (RAM). 
     The above descriptions are merely embodiments of the present invention, but are not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made without departing from the spirit and principle of the present invention should fall within the scope of the present invention as defined by the appended claims.