CN101904139A

CN101904139A - Adaptation scheme for communications traffic

Info

Publication number: CN101904139A
Application number: CN2008801220957A
Authority: CN
Inventors: 尼尔·哈里森; 艾伦·麦奎尔
Original assignee: British Telecommunications PLC
Current assignee: British Telecommunications PLC
Priority date: 2007-12-20
Filing date: 2008-12-19
Publication date: 2010-12-01
Anticipated expiration: 2028-12-19
Also published as: EP2232786A1; WO2009081128A1; EP2232785A1; WO2009081139A1; CN101904139B; CN101926131A

Abstract

A method of generating a generic framing procedure hierarchy comprising processing a first generic framing procedure frame to determine the overall length of the generic framing procedure frame, mapping the frame into the generic framing procedure payload area of a second generic framing procedure frame at the next level of the generic framing procedure hierarchy, whereby information enabling the size of the generic framing procedure payload remaining after that frame has been extracted is captured in the header fields of the generic framing procedure frame into which the first frame is encapsulated, and wherein the generic framing procedure header indicates whether there are more frames left in the mapping hierarchy when de-encapsulating (i.e., running down) the generic framing procedure frame stack by providing an indicator at level N of the hierarchy that at the level N-1 there is a generic framing procedure frame to extract.

Description

The adaptation scheme of communication service

Technical field

The present invention relates to form the method for stack Generic Framing Procedure (generic framing procedure) frame staging hierarchy (hierarchy).

Specifically but not exclusively, the GFP staging hierarchy can provide adaptation layer (adaption layer) for ethernet communication protocol.It is professional and need not client's business of every type of in ethernet frame header indication that the GFP adaptation layer makes it possible on the carrying ethernet network a plurality of clients of carrying.

Specifically but not exclusively, the present invention relates to a kind of GFP of making can carry with the control domain of the different operators of isolating communication network on GFP and/or can to carry out GFP multiplexing.

Background technology

The European patent application EP 181068 of by name " Method and Device for Generic Framing Procedure Encapsulation " has been described how with a plurality of protocol Data Units (protocol dataunit, PDU) be cascaded as the cascade bag, this cascade bag is encapsulated in the gfp frame subsequently.Also described a kind of device of the GFP of being used for encapsulation, this device comprises the cascade module of a plurality of PDU of cascade with formation cascade bag, and encapsulation cascade bag is to obtain the GFP package module of GFP bag.Thereby the technology that EP 181068 proposes has increased the occupation rate of payload in the single gfp frame and has improved transmission efficiency.

Yet in EP 181068, in order to extract bag from the cascade bag, whole cascade bag must be separated cascade.

U.S. publication application US2004/0252720 has described a kind of the transmission in the frame at a frame mapping G FP who follows the GFP agreement many fiber channels (Fibre Channel is provided, FC) technology of frame only will be come each FC frame of mark with distributed delimiter in the payload of this GFP transmission frame.

U.S. publication application US2005/0169275 has described a kind of method that transmits high-level PDU on the low level agreement, has specifically described how can to transmit multiprotocol label switching (MPLS) PDU by following steps: add unsettled (pending) MPLS PDU to the payload information district of GFP Frame (PIA); Via transmit network the GFP Frame is sent to the destination node; And from the PIA field of GFP Frame, obtain MPLS PDU at this destination node.

Yet, extract the business unit of single encapsulation a plurality of business unit that people expectation can be carried and need not from gfp frame, to extract every other business unit in the carrying gfp frame.

Summary of the invention

One aspect of the present invention seeks to provide a kind of method that makes customer data be suitable for transmitting in communication system, this method may further comprise the steps:

Client's frame of Generic Framing Procedure communication protocol is followed in reception; And

Described client's frame is mapped to the payload zone of one or more load carrying frame, and each load carrying frame is all followed Generic Framing Procedure communication protocol.

Described carrying general framing procedure frame can be mapped to the payload zone of protocol Data Unit of the employed communication protocol of bearer network of described communication system.

Described bearer network communication protocol can comprise ethernet communication protocol.Alternatively, described bearer network communication protocol comprises MPLS communication protocol.

General framing procedure frame can comprise header, and this header has the extended field of the sequence number of the fragmentation state that is configured to indicate its payload and payload section.

General framing procedure frame can comprise header, and this header has the extended field of the channel logo that is configured to indicate its payload.

Another aspect of the present invention seeks to provide a kind of method that makes customer data be suitable for transmitting in communication system, this method may further comprise the steps: receive client's frame of following Generic Framing Procedure communication protocol; Described client's frame is mapped to the payload zone of a plurality of load carrying frames, and each load carrying frame is all followed Generic Framing Procedure communication protocol and is had the fragmentation state that is configured to indicate its payload and the extended field of the sequence number of payload section.

Recombinate client's method of the segment data that a kind of basis transmits on communication system, this method may further comprise the steps: receive a plurality of load carrying frames of following Generic Framing Procedure communication protocol; The extended field of the header of each in described a plurality of load carrying frames is handled to determine whether it has indicated the fragmentation state of its payload and the sequence number of payload section; If detect a plurality of sections of same client's frame, then handle described a plurality of frame to extract each payload section; According to the described payload section described client's frame of recombinating.

This method can be implemented on the node that is configured to provide in the communication network of assembling service, wherein this gathering service is used for the bearer network that visits to one or more higher rate port by this node from the client's service integration that receives than the low rate port, and this method may further comprise the steps: receive a plurality of client's frames from a plurality of than the low rate port; Client's business is mapped to the payload zone of one or more described client's Generic Framing Procedure communication protocol frame; Wherein when each client's general framing procedure frame being mapped to the payload information zone of load carrying frame, each load carrying frame of following Generic Framing Procedure communication protocol all has the extended field of the channel number that is configured to indicate its payload, and wherein each carrying general framing procedure frame all is mapped to the payload zone of the protocol Data Unit of bearer network communication protocol.

Can be provided with being provided for from than the gathering service to the higher rate port of the service integration of low rate port this method, this method may further comprise the steps: from a plurality of a plurality of client's frames of following Generic Framing Procedure communication protocol that receive than the low rate port; Each client's frame is mapped to the payload information zone of load carrying frame, and each load carrying frame is all followed Generic Framing Procedure communication protocol and is had the extended field of the channel number that is configured to indicate its payload.

Another aspect of the present invention seeks to provide a kind of method that produces the Generic Framing Procedure staging hierarchy, and this method may further comprise the steps: first general framing procedure frame is handled to determine the total length of this general framing procedure frame; This frame is mapped to the Generic Framing Procedure payload zone of other second general framing procedure frame of next stage that is positioned at described Generic Framing Procedure staging hierarchy, wherein catches the information that makes that the size of Generic Framing Procedure payload can remain unchanged after this frame is extracted in one or more field in the header of the general framing procedure frame that described first frame is packaged into.

Whether the Generic Framing Procedure header indicator can indicate also to remain in the mapping staging hierarchy when the general framing procedure frame stack is carried out decapsulation frame.

Header indicator can be provided at the indication that there is the general framing procedure frame that will extract in the N-1 level at the level n place of staging hierarchy.

Another designator in the payload header can be indicated and be no longer included the general framing procedure frame that will extract, and the staging hierarchy of general framing procedure frame stops.

Another aspect of the present invention seeks to provide a kind of method of using the customer data that above any means is suitable for transmitting in communication system that recovers, this method may further comprise the steps: the node place in described communication system handles the frame that receives, to determine whether its payload comprises the frame of following Generic Framing Procedure communication protocol; And if payload is Generic Framing Procedure communication protocol frame, then:

I) described payload is carried out decapsulation;

Ii) the header fields of the general framing procedure frame that deblocking is taken on is handled; And

Determine iii) whether described payload also comprises one or more Generic Framing Procedure communication protocol frame, if then repeat above step I) arrive iii).

This method can also may further comprise the steps: one or more extended field of the header of the general framing procedure frame that each deblocking is taken on is handled, to determine whether to exist the Channel Identifier of the channel logo of indicating the client signal that described payload was derived from.

This method can also may further comprise the steps:

One or more extended field to the header of each general framing procedure frame is handled, with one or more value of the described extended field of the sequence number that determines whether to exist the fragmentation state of indicating its payload and payload section.

This method can also comprise: if detected a plurality of sections of same client's frame, then

Described a plurality of frames are handled to extract each payload section;

According to the described payload section original payload of recombinating.

Another aspect of the present invention seeks to provide a kind of equipment that comprises one or more parts of the step in any method that is provided to realize above method aspect.

One aspect of the present invention seeks to provide a kind of equipment, and this equipment comprises:

Processor, it is set to first general framing procedure frame is handled to determine the total length of this general framing procedure frame;

Mapper, it is set to first frame is encapsulated into the Generic Framing Procedure payload zone of other second general framing procedure frame of next stage that is positioned at described Generic Framing Procedure staging hierarchy,

Wherein in the header fields of the general framing procedure frame that described first frame is packaged into, catch the information make that the size of Generic Framing Procedure payload can remain unchanged after this frame is extracted.

Whether the Generic Framing Procedure header indicator has indicated also to remain in the mapping staging hierarchy when the general framing procedure frame stack is carried out decapsulation frame.

One aspect of the present invention seeks to provide a kind of method that produces the Generic Framing Procedure staging hierarchy, and this method may further comprise the steps:

First general framing procedure frame is handled to determine the total length of this general framing procedure frame; And

This frame is mapped to the Generic Framing Procedure payload zone of other second general framing procedure frame of next stage that is positioned at described Generic Framing Procedure staging hierarchy,

If there is the general framing procedure frame that will extract in the more rudimentary other places at this stack, then by each level in this stack staging hierarchy designator is set, whether the Generic Framing Procedure header can indicate also to remain in the mapping staging hierarchy when the general framing procedure frame stack is carried out decapsulation frame.

Another aspect of the present invention seeks to provide a kind of method that produces the Generic Framing Procedure staging hierarchy, and this method may further comprise the steps:

First general framing procedure frame is handled to determine the total length of this general framing procedure frame;

Wherein in the header fields of the general framing procedure frame that described first frame is packaged into, catch the information make that the size of Generic Framing Procedure payload can remain unchanged after this frame is extracted, and wherein be provided at the designator that there is the general framing procedure frame that will extract in the N-1 level by the level n place in described staging hierarchy, whether described Generic Framing Procedure header indicator has indicated also to remain in the mapping staging hierarchy when the general framing procedure frame stack is carried out decapsulation frame.Decapsulation is handled and is comprised the described general framing procedure frame stack of dismounting (run down).

In one embodiment, another designator in the described payload header has been indicated and has been no longer included the general framing procedure frame that will extract, and the staging hierarchy of described general framing procedure frame is terminated.

Another aspect of the present invention seeks to provide a kind of equipment, and this equipment is provided to realize this method aspect, and this equipment comprises:

Wherein in the header fields of the general framing procedure frame that described first frame is packaged into, catch the information make that the size of Generic Framing Procedure payload can remain unchanged after this frame is extracted, and wherein be provided at the designator that there is the general framing procedure frame that will extract in the N-1 level by the level n place in staging hierarchy, whether the Generic Framing Procedure header indicator has indicated also to remain in the mapping staging hierarchy when the general framing procedure frame stack being carried out decapsulation (promptly removing) frame.

One aspect of the present invention seeks to provide a kind of adaptation layer that is used for the bearer network service, it makes a plurality of client's business unit (for example protocol Data Unit PDU) can be encapsulated in the single adaptation layer business unit, is encapsulated in then in the payload zone (being also referred to as service data unit) of described bearer network.

When network node received carrying PDU, it can be handled the PDU header and whether comprise the adaptation layer signal with the payload zone of determining the bearing protocol data cell.If there is adaptation layer signal according to embodiment of the present invention, then it to be handled, this makes it possible to obtain each client signal PDU and is encapsulated in the interior position of described adaptation layer signal payload.This makes it possible to extract each client PDU the adaptation payload zone in load carrying frame payload zone, and does not need to be extracted in together any other client PDU that carries in same load carrying frame payload the zone in.This make load carrying frame can with than mode as known in the art more flexible way carry various client signals.

More than and claims set forth aspect of the present invention, more than and claims also set forth preferred implementation.

Those skilled in the art obviously can find, the present invention can comprise herein with claim in the aspect set forth and any appropriate combination of preferred implementation.

Description of drawings

Preferred implementation of the present invention is only described below with reference to accompanying drawings by way of example, wherein:

Fig. 1 has schematically shown standard gfp frame form in more detail;

Fig. 2 A schematically shows the staging hierarchy rank according to the gfp frame stack of embodiment of the present invention;

The staging hierarchy rank that Fig. 2 B schematically shows the gfp frame stack shown in Fig. 2 A is used for comparing with Fig. 2 C;

Fig. 2 C schematically shows the staging hierarchy rank of gfp frame stack, and wherein the client of stack comprises a plurality of gfp frames according to embodiment of the present invention;

Fig. 2 D schematically shows three grades of classification system gfp frame stacks, and wherein the middle rank of stack and client comprise a plurality of gfp frames according to embodiment of the present invention;

Fig. 2 E shows and can be how the frame at level n place be segmented into a plurality of frames according to embodiment of the present invention;

Fig. 3 schematically has been shown in further detail the GFP stack according to embodiment of the present invention;

Fig. 4 shows the GFP header extension field according to embodiment of the present invention, and it provides the data transfer scheme of client's business being carried out segmentation;

Fig. 5 A shows the GFP header extension field according to embodiment of the present invention, and it provides GFP client's business is carried out multiplexing data transfer scheme;

Fig. 5 B shows the GFP header extension field according to embodiment of the present invention, and it provides and has carried out multiplexing and data transfer scheme segmentation to client's business;

How Fig. 6 schematically shows according to embodiment of the present invention is single carrying GFP data channel with a plurality of client GFP channel multiplexings;

Fig. 7 schematically shows according to embodiment of the present invention how unsegmented client GFP Frame is segmented into a plurality of carrying gfp frames;

Fig. 8 A schematically shows the encapsulation node according to embodiment of the present invention;

Fig. 8 B schematically shows the decapsulation node according to embodiment of the present invention;

Fig. 9 A shows the step according to the method that the client is encapsulated of embodiment of the present invention; And

Fig. 9 B shows and according to embodiment of the present invention the payload of load carrying frame is carried out the step of the method for decapsulation.

Embodiment

The various details preferred forms.It will be appreciated by those skilled in the art that, for the sake of clarity specification of the present invention is simplified, no longer explicitly is mentioned the feature that those skilled in the art can expect or know, because its enforcement is very basic, these features will implicitly be included in the specification of the present invention.Specification can also omit mentions alternate feature, and it is equivalent to the feature of mentioning herein on function.

Fig. 1 of accompanying drawing shows gfp frame form known in the art, can change it, comes as the adaptation layer according to embodiment of the present invention.The gfp frame form has the feature of the agreement defined in the G.7041 standard of being set up by international telecommunication union telecommunication standardization (ITU-T), incorporates the content of this standard by reference at this.

One of skill in the art will appreciate that the GFP agreement is designed to a kind of general mapping mechanism of the TDM of bag technology.GFP supports multi-protocols, and can expand.Preferred implementation of the present invention is used the GFP based on frame, but in alternative embodiment of the present invention, has used transparent GFP (GFP-T).GFP-T is the expansion to GFP, and being provides effective low latency support for the high speed WAN that comprises storage area network is used.The character stream of GFP-T processing block coding (for example 8B/10B), rather than deal with data (packet-by-packet) frame by frame.

In an embodiment of the invention, layering GFP mapping scheme provides adaptation layer to the service of Ethernet bearing network.Layering GFP mapping scheme adaptation layer makes it possible to a plurality of client signals of carrying in ethernet frame, following description, and for example, as what in the common pending application application of " the CLIENT/SERVERADAPTATION SCHEME FOR COMMUNICATIONSTRAFFIC " by name that require priority GB0724936.0, describe, incorporate the full content of this application by reference at this.

As Fig. 1 schematically illustrated, the structure of GFP client's frame comprised core header, payload header, optional extension header and optional payload Frame Check Sequence (FCS).One of skill in the art will appreciate that for clarity sake, can be from figure and the following description book in omit gfp frame and the incoherent field of context herein.

Core header has the field of having indicated payload length, and it is to have indicated 2 bytes (8 eight bits) field that what bytes (bit eight hytes) are arranged in the GFP payload zone.By the payload FCS expense that deducts follow-up payload header and exist alternatively from the payload zone, the payload length value has also been indicated the size of actual customer payload information.Payload header is a variable-length zone, comprises two essential fields and some optional extension headers.Two essential type fields are payload type fields, its PT Payload Type most significant byte (MSB) and PT Payload Type least significant byte (LSB) are shown in Figure 1, and header error correction (HEC) field, its type HEC MSB and type HEC LSB are shown in Figure 1.

Payload type field has a plurality of son fields.Payload type identifier (PTI) has identified the type of frame, can get two values: user data frame and customer account management frame.Payload FCS designator (PFI) son field has indicated whether there is payload FCS.Extension header designator (EXI) has been indicated the type of the extension header in the gfp frame.Be known in the art three types of extension headers, that is, and empty extension header, at the linear expansion header of point to point network, and at the annular expansion header of loop network.Also show user's payload identifier (UPI) son field in addition, it has identified the type of the payload in the gfp frame.Set UPI according to the client signal type that transmits, had a plurality of definition value at communication protocol such as Ethernet, PPP, IP, MPLS, fiber channel, FICON, ESCON and G bit Ethernet.

The payload information field has comprised customer data.As mentioned above, the client who has defined two kinds of patterns at GFP adapts to, that is, and and frame mapping G FP and transparent mapped GFP.Frame mapping G FP payload is made up of the bag of variable-length, and client's frame integrally is mapped to a gfp frame.In transparent mapped GFP, many customer data characters (being mapped as block code) have been carried in the gfp frame.

According to the embodiment of the present invention, layering GFP mapping is to use PTI, EXI and UPI field to realize.

Fig. 2 A, Fig. 2 B, Fig. 2 C, Fig. 2 D, Fig. 2 E and Fig. 3 schematically show and how one or more gfp frame can be mapped in another gfp frame.It is recursive creating staging hierarchy that mapping is handled, if at each level mapping bigger frame in next rank of this staging hierarchy always.If not, then frame is segmented into a plurality of small fragments, and these small pieces are mapped in a plurality of frames.

Shown in Fig. 2 A and 2B, each gfp frame all is stacked in the payload of this gfp frame in the more rudimentary other places of this staging hierarchy.As shown in the execution mode of Fig. 1 and 2 A, rank than first rank (payload will comprise customer data) more the payload of each gfp frame of eminence all comprise the content of another gfp frame.The rank of GFP staging hierarchy is low more, and rank is more near client layer.In some embodiments of the present invention, client layer can have the rank higher than the GFP in the open system interconnection communication protocol stack, but in other execution modes of the present invention not necessarily this situation.For example, levels of clients can comprise GFP once more, or Internet Protocol or asynchronous transfer mode, for example the client layer communication protocol of embodiment of the present invention.Similarly, the rank of GFP staging hierarchy is high more, the approaching more carrying of staging hierarchy rank (or ground of equal value, server) layer.The highest level of the frame in the GFP staging hierarchy will by 1:1 be mapped to the payload of the frame in the bearer network, making payload in each highest level frame (level n among Fig. 2 B) then be mapped to follow provides the payload of frame of communication protocol of the network of carrying service to the network that sends client signal.In some embodiments of the present invention, network has than other communication protocol of GFP even lower level in the OSI communication protocol stack in carrying (ground of equal value, server), but situation is really not so in other execution modes of the present invention.For example, bearer network can use possible bearer network tranmission techniques, for example GFP or Ethernet or MPLS or one of ATM communication protocol and variant thereof.

Fig. 2 C shows in the single rank of GFP staging hierarchy and how a plurality of gfp frames can be cascaded.In Fig. 2 C, at level n-1 place, two gfp frames are disposed in the payload zone of other single gfp frame of even lower level of this staging hierarchy.Rank N-1 frame has carried identical client signal in Fig. 2 C, but alternatively, in other execution modes of the present invention, the payload of some N-1 level frame can derive from one or more different client signal.In another embodiment of the present invention, two or more level ns-1 frame has carried the section (or alternatively, level n-2 frame is seen Fig. 2 D) of same client frame, and their header also will the section of comprising designator and sequence information in the case.

Fig. 2 D schematically shows other GFP staging hierarchy of 3 levels, and wherein at rank 1 place, 4 frames are connected on together in the payload of the single frame at rank 2 places of this frame staging hierarchy.The payload of each rank 2 frame can both have the internal data structure of the internal data structure that is independent of any other frame in the payload that also is mapped to rank 3GPF frame.Therefore, shown in Fig. 2 D, left-hand side rank 2 frames have the payload that comprises 4 rank 1 frames.Right-hand side rank 2 frames except customer data without any extra internal data structure.Two rank 2 frames all are mapped in the payload zone of rank 1GFP frame.The payload zone that rank 1GFP frame can be mapped to bearer network PDU subsequently is so that transmit on bearer network.

Fig. 2 E shows in embodiments of the present invention, how the gfp frame in the arbitrary number of level other places of GFP staging hierarchy is segmented into a plurality of gfp frames of the same levels that occupies this GFP staging hierarchy.Each gfp frame header is made amendment to indicate its payload with segmentation and be provided with sequence indicators in its extended field, such as described in more detail below.This makes the client signal with big PDU or data structure can at first be mapped as gfp frame, and then gfp frame is segmented into a plurality of littler gfp frames.These littler gfp frames can be mapped as the bearer network frame of equal amount subsequently.

Fig. 3 shows from the information of each grade of gfp frame stack and how to be carried by other gfp frame of the next stage of GFP stack.As shown in Figure 3, the PDU length indicator of the gfp frame in first order other places is processed will occupy what bits eight hytes (being byte) with the encapsulation fields in the GFP payload zone in the next stage other places of determining to be mapped to this staging hierarchy.This information makes it possible to extract the tunneling data cell at client's service signal (is another gfp frame) in Fig. 2 and embodiment of the present invention shown in Figure 3, be extracted afterwards that the size of GFP payload remains unchanged because it allows to determine this frame in " separating mapping " handles.Also make the node of any this signal of reception can both determine whether other gfp frames will be by decapsulation in addition in the payload zone.For example, in Fig. 2 C, after level n frame packaging area deblocking takes on the other N-1 frame of the first order, if the total length of level n frame payload is not carried out decapsulation as yet, the node that then carries out decapsulation will continue to handle the bit stream that is received based on another N-1 rank gfp frame in N rank GFP payload zone.

In addition, the payload header information that encapsulates the gfp frame of another gfp frame has been indicated anything to be carried and has been gfp frame or other guide.In order to realize layering GFP mapping, the GFP header indicator has indicated when decapsulation (being stepping) gfp frame stack whether remain more frame in the mapping staging hierarchy.Be arranged on designator indication in the header of gfp frame at level n place of frame stack staging hierarchy understand encapsulation process will be overlapped generation (re-iterated) with decapsulation from just by the gfp frame in the payload of the gfp frame of decapsulation, that is, exist one or more gfp frame to extract in next rank.Any other designator in the payload header has been indicated and has been no longer included the gfp frame that will extract, and the staging hierarchy of gfp frame is terminated.In an embodiment of the invention, when will being used GFP mapping scheme according to the present invention to go up when transmitting as the carrying communication network (for example wide area network or WAN) that adapts to agreement from the data of client communication network (for example local area network (LAN) or LAN), the payload of the frame in the GFP staging hierarchy in the minimum rank comprises the data of following the communication protocol that customer network supports.

In an embodiment of the invention, the GFP business that produces in first network domains is encapsulated in the GFP that other network domains provide.This can carry business that the bearer network of winning provides with transparent mode and need not the example of public control plane on second bearer network.

GFP generally has proprietary expansion and/or mapping, otherwise comes in the past can throw into question between network domains when professional.In an embodiment of the invention, because the GFP protocol stack comes it is isolated by the proprietary field of carrying a network domains in the next frame rank of gfp frame staging hierarchy, encapsulate proprietary field with the gfp frame payload zone on other network domains thus, be removed so each boundary node between network domains always will be checked the requirement of client's business.

Other execution modes of the present invention have realized (no matter whether they have carried the section from same client's frame individually for the segmentation of client's frame in the bearer network and a plurality of gfp frame, as long as can be jointly in route at least a portion of bearer network) series connection in another gfp frame, another gfp frame can be mapped to load carrying frame payload zone subsequently.

Thus, embodiments of the present invention provide a kind of data transfer scheme, wherein payload header and/or optional extension header are adjusted so that client's frame can carry in load carrying frame, all the other all affairs can both be incorporated their content at this by reference to handle such as the normal mode of describing in the various GFP standards G.7041.

In an embodiment of the invention, the GFP stack is arranged that GFP is multiplexing frame by frame in greater detail below supporting.Another embodiment of the present invention uses the GFP extension header of gfp frame to indicate the segmentation or the series connection of the gfp frame that carries in its payload.

In these execution modes, term " carrying " gfp frame is represented such frame, its effectively with middle encapsulated client's gfp frame partly or entirely; Frame or frame section that term " client " expression is packed, that is, and the relation of each frame in the frame staging hierarchy.Thus, in three layers of staging hierarchy, the frame in the intermediate layer is the carrying of ground floor, and is the 3rd layer client.No matter each gfp frame is that standard GFP communication protocol (for example GFP-T, GFP-F and other variants) is all followed in client or carrying, therefore comprises: core header, payload header, payload zone, optional extension header and optional payload Frame Check Sequence.In fact, in a plurality of execution modes of the present invention, " client " GFP self will comprise the data that derive from client signal, and the carrying gfp frame is mapped to payload or the service data unit of the PDU of bearer network.

The carrying gfp frame has payload header, it is the 4-64 byte long, comprise: be used to realize 2 bytes of the present invention type field, guarantee the header error control (HEC), the optional extension header of 0 to 58 byte long of 2 bytes that are called as tHEC (using) of the integrality of type field, and the optional 2 byte header mistakes controls (HEC) that are called as eHEC (if exist then use) of guaranteeing the integrality of optional extension header with canonical form with its canonical form.

In the carrying gfp frame, indicate the existence of the gfp frame in the payload that is encapsulated in gfp frame by the GFP type field in payload header and/or the optional extension header.

The payload header support is for the distinctive data link management rules of client signal (in other words, payload) of being carried.The payload header type field is subdivided into following a plurality of field:

I) payload type identifier of 3 bits (PTI).It has identified the type of GFP client's frame.Below the current definition: 000 to have identified these frames be customer data (user data frame), and 100 at the customer account management frame, and other values are reserved so that further research.The GFP client data frame is used to send the data from client signal.GFP customer account management frame is used to transmit the information that the management that is connected with client signal or GFP is associated.

The ii) payload FCS of 1 bit (Frame Check Sequence) designator (PFI).It has been indicated and has had (being set at 1) or do not have (being set at 0) payload FCS field.

The iii) extension header designator of 4 bits.

Iv) user's payload identifier (UPI) of 8 bits is used to indicate the type of the payload of carrying in the GFP payload information field.

An execution mode according to the method for transmission data of the present invention is set at a class value with type field and son field thereof.In this execution mode, customer data is used client data frame and transmits on GFP.GFP client's frame that these frames are made up of core header and payload zone.The type field of client data frame is set to subsequently:

PTI＝000

The PFI=payload is peculiar

The EXI=payload is peculiar

The UPI=payload is peculiar

Whether allow Frame Check Sequence (FCS) will determine the value of payload FCS designator (PFI) to be set to 1 or 0.UPI has indicated what client's payload is.For example, the frame that is mapped to Ethernet has and is set to 00000001 UPI.At present, 00010011 to 11101111 be reserved so that carry out standardization from now on.Therefore in order on GFP-F, to transmit GFP-F, select to give in advance the value (11110000 to 11111110) or the unappropriated value of special purpose and its branch be equipped with the GFP that represents the frame mapping just enough, else if GFP client be GFP-T and carry the service be GFP-F, then need another UPI at least.

The payload extension header is intended to the distinctive data link header of supporting technology, such as virtual link identifier, source/address, place, port numbers, service type, the control of extension header mistake etc.The type of extension header is decided by the content of EXI bit.It will be apparent to those skilled in the art that in invention day and defined following three kinds of extension header variants:

When EXI=0000, extension header is empty.There is not independent extension header in the case, and do not have eHEC.This is applicable to point-to-point situation, wherein is intended to transfer path is exclusively used in a client signal.In this embodiment, the transfer scheme with two-stage gfp frame staging hierarchy comprises the single GFP stream of being supported by encapsulation GFP.This can for example take place to allow professional packed so that going out to transmit on the port on port in point-to-point configuration.In this embodiment, if there is no segmentation then in extended field carrying gfp frame header will have the EXI=0000 value.

When EXI=0001, extension header is linear header.It is intended to the application of linearity (promptly point-to-point), and requires to use adaptation layer to carry out the gathering of client signal.This GFP that is used in embodiments of the present invention in the designation data transfer scheme is multiplexing, has wherein supported more than one client GFP signal by encapsulation GFP.In the case, the initial form field of carrying GFP header will comprise:

PTI＝000；

PFI=0 or 1;

EXI＝0001；

The UPI=payload is peculiar

In one embodiment, carrying GFP (rank 2 frames) payload has the length restriction of N eight hytes.Have M GFP encapsulation client's frame (rank 1 frame), each is N eight hytes.If realize the 1:1 mapping between carrying (N=2) payload and client GFP (N=1) frame business, the payload of then each carrying (rank 2) gfp frame has been carried single client's gfp frame (rank 1).Amount to, will need M carrying gfp frame to carry M client signal.Yet, if require frame to share, if for example single carrying gfp frame is shared between a plurality of client's frames, promptly, implement the mapping of M:1 client to carrying, then each load carrying frame payload has all been carried M different client's payload section, and wherein each payload section all comprises N/M eight hytes.Yet, will need to amount to M load carrying frame and send each client N eight hytes (seeing Fig. 7 described below).

In the case, if gfp frame is mapped to the maximum sized payload information zone greater than the payload zone, then need to provide Segmentation and Reassembly (reassembly) mechanism of some form.

This in according to an execution mode of data transfer scheme of the present invention by for the carrying gfp frame provide new extension header to provide.In this embodiment, it is point-to-point that communication system is considered to, and do not have the multiplexing of a plurality of streams.Data transfer scheme mapping some of them frames (but not necessarily whole) have the stream of the size bigger than the effective load region of encapsulation.If all client's frame is all less, then certain such extension header does not realize required for the present invention wanting.

In the case, need to be defined as can be the value of extracting from one of them present untapped extension header to the EXI value.The extension header that provides has spare field and header error verification, and whether the frame that comprises the data of 4 bytes now and definite encapsulation is provided by segmentation, if be first section, interlude or last device that falls, and sequence number is provided.

Fig. 4 illustrates in greater detail the exemplary internal structure according to this GFP extension header of the present invention.In Fig. 4, the header fields of 4 bytes is segmented into the header field of extension header error checking least significant byte (eHEC LSB) field of 8 bits, extension header error checking most significant byte (eHEC MSB) field of 8 bits, idle 8 bits, sequence number field and 2 single bit field, E-field and the B-field of 6 bits.Shown E-field and B-field have fully been indicated the situation that takes place in the segment processing or the fragmentation state of payload in other words.Sequence number has indicated the order of section to help its reorganization when recovering from the carrying service.For example, the starting point that E=1 and B=1 indicate a series of segments can be set, the terminal point that E=0 and B=0 indicate a series of segments is set, E=1 and the B=0 section (this may need sequence number to indicate its tram) in the middle of indicating is set, E=0 and B=0 are set indicate and do not have segmentation.

Fig. 5 A and Fig. 5 B all show in an embodiment of the invention of the multiplexing scheme that realize to require to provide Channel Identifier and how GFP type extension header are configured.Header among Fig. 5 A comprises CID field or channel id field, and it is 1 byte long, thereby can identify 256 different communication channels between the GFP.In the embodiments of the present invention shown in Fig. 5 A, the idle bytes that is not used has been shown, but this byte is used in the embodiments of the present invention shown in Fig. 5 B in extended field, wherein this idle bytes is used to support the segmentation of client's frame.

Embodiments of the present invention use the CID field of gfp frame to come multiplexing a plurality of GFP sessions, and each session identifies with the gfp frame of the CID with different value.The gfp frame header is 8 byte longs, and about 65000 byte longs in payload zone can multiplexing a plurality of GFP sessions in the encapsulation gfp frame.Like this, the maximum quantity of session that can be multiplexing is 256, although this quantity is probably much smaller than 256 in the reality, the physical constraints of the number of sessions that can be re-used depends on the length of the length of packed frame less than encapsulation gfp frame payload information field.By using CID value and predetermined UPI, a plurality of GFP sessions can be carried in same gfp frame in an embodiment of the invention.This makes port that client's business can be from the multiplexed port of low rate more to higher rate so that point-to-point gathering service to be provided.

How Fig. 6 illustrates in greater detail two channel Mapping of client's frame payload to Bearer Channel.In Fig. 6, come client's frame n of self-channel 0, n+1, n+2 and n+3 illustrate in the left side, come client's frame n of self-channel 1, n+1, n+2 and n+3 illustrate on the right side.Each frame all at first is mapped to the payload information of gfp frame, and it is mapped to the payload zone of carrying gfp frame subsequently with payload header, extension header and FCS.Each client's frame all is to use the extension header shown in Fig. 5 A and 5B mapped,, comprises that the extension header of Channel Identifier (CID) value of the payload that has identified the encapsulation gfp frame is associated with concrete channel that is.In the case, CID value that channel 1 is mapped, this value payload that identified the carrying gfp frame is associated with channel 1.Channel 2 similarly is to use and comprises the extension header that identified the payload CID value related with channel 2 and mapped.

In Fig. 6, for carrying stream, the time flatly flows on the direction of arrow that is positioned at the bottom, and frame is made the horizontal frame stream of frame that first frame is shown in the left side come self-channel 0 by the 1:1 mapping, and the next one comes self-channel 1, and the next one comes self-channel 0 again.CID then identifies the channel under certain frame simply.If client's gfp frame is less than or equal to the payload information zone, then can use extension header with form shown in Fig. 5 A.Yet, if not, need to catch extraneous information as mentioned above, and can use the extended field shown in Fig. 5 B.

Being used for client's frame is mapped to the multiplexing process that payload information then is mapped to the payload zone of GFP load carrying frame stream can be any multiplexing process that is applicable to this purpose well known by persons skilled in the art, and can use for the purposes of the present invention similarly and the known solutions multiplexing process suitably adjusted realizes that demultiplexing handles.

Fig. 7 shows the frame segmentation and how to take place.In Fig. 7, comprise that the not segmentation gfp frame of X byte payload is divided into a series of X/n byte payload section.In Fig. 7, first section of the X/n byte will carry in a GFP load carrying frame, and every other carrying gfp frame will carry the section of identical size, and except last carrying gfp frame, it carries remaining payload.If therefore X=10, and X/n=2 byte, then 5 each of carrying in the gfp frame are all carried 2 bytes.Yet, if X=11, and the X/n=2 byte, last (the 6th) carrying gfp frame will carry 1 byte.

The present invention can be used in the multiple network situation.For example, an embodiment of the invention make it possible to realize data transfer scheme in the communication system that comprises single network and GFP carrying service.At this, GFP transfer equipment (for example Line cards) be set at network the edge (for example first and last SDH (Synchronous Digital Hierarchy) interconnection in).The GFP framing only occurs over just the edge of position, promptly at these some places, thereby no longer need carry out any processing in network.

In another embodiment of the present invention, realize data transfer scheme comprising in GFP carrying provides the communication system of the 2nd GFP carrying of service.At this moment in communication network, exist 3 GFP to jump, at first jumping into/going out and mid point between them at the edge of two GFP carrying services.If first jump and final jump on carry out GFP-T, and carry out GFP-F in middle hop, then in each GFP-T frame (because the GFP-T support comprises the line code of intermediate frame gap and lead code and frame) than in each GFP-F frame, having transmitted more information.In order to shine upon line code information, can realize data transfer scheme as shown in Figure 7, the GFP-T frame that it will be bigger is segmented into a plurality of GFP-F frames.Similarly, jump and the 3rd jumping if mapping is exclusively used in first in the network, then in middle hop, mapping need be held, and its data transfer scheme that can reuse according to realization GFP-in-GFP of the present invention (being layering or segmentation GFP) realizes.

In one embodiment, communication system uses GFP as the interface to line system, and it is not supported by TDM communication protocol.In this embodiment, carrying GFP service will have in communication network each jump onto processed GFP business.By realizing the data transfer scheme according to embodiment of the present invention, all special-purpose client GFP is professional then to be transmitted on network pellucidly.

Fig. 8 A and Fig. 8 B schematically show some functional parts that are used for realizing in communication system embodiments of the present invention that need respectively in the boundary node 10,22 between customer network (not shown) and the bearer network (not shown).Fig. 8 A and 8B are greatly simplified.For clear, those skilled in the art think that realization is omitted according to the necessary parts of the adaptation scheme of embodiment of the present invention.Shown in the figure and parts described below be for the example purpose.In other embodiments, they can be removed, make up or be replaced by function equivalent well known by persons skilled in the art.

Fig. 9 A shows the step in the embodiments of the present invention, wherein the node shown in Fig. 8 A with the client signal data encapsulation in the load carrying frame data structure so that on bearer network, propagate.

Fig. 9 B shows the step in the embodiments of the present invention, wherein the node shown in Fig. 8 B from the load carrying frame data structure decapsulation client signal data so that propagate in customer network.

In Fig. 8 A, node 10 has played the function of the encapsulation point of client's business.The receiver 12 of node 10 receives client's service signal (step 40 shown in Fig. 9 A).Data processor 14 is handled to determine whether needs segmentation (step 42) according to its data structure each client's business unit that receives then.This processing is determined client signal is mapped to one or with one or more feature of the required client signal of a plurality of GFP adaptation layer frames, for example, the size of the type of client signal communication protocol (if for all professional differences that receive), client signal protocol Data Unit (PDU) and/or SDU routing iinformation etc.

If do not need segmentation, then whole client PDU is mapped to the payload of GFP adaptation layer.If the total amount of customer data in each payload zone that is mapped to GFP adaptation layer frame is greater than scheduled volume, for example depend on the amount of the full-size (size by the service data unit SDU of the communication protocol of this bearer network is determined) of the payload that bearer network PDU can support in one embodiment, then carry out segmentation by 16 pairs of client signal payload of data sementation device.

If do not need segmentation, then client signal PDU is directly delivered to data mapper 18 so that be encapsulated in the payload zone of gfp frame, and generates suitable GFP header by data processor 14.If a plurality of different client signals (for example client's channel or data flow) are mapped to single Bearer Channel signal so that transmit in bearer network, then each gfp frame will comprise the indication of client's channel that its payload is derived from its header.

The gfp frame that has encapsulated client signal subsequently by data mapper 18 decapsulations in carrying gfp frame (its payload zone of DPU that is mapped to bearer network subsequently is so that transmitted on bearer network by suitable reflector), or directly deblocking installs in the payload zone of carrying PDU.Like this, when bearer network was Ethernet, the carrying ethernet frame only needed to comprise the GFP ethernet type, and irrelevant with the communication protocol type of client signal.

If carry out segmentation, then the data that form each client PDU payload section are rebuild (step 44).Each client PDU for mapper 18 receptions, client's payload (ground of equal value, client SDU) be mapped to the payload of the first rank gfp frame together with the copy of client's frame header, and the communication protocol type of client signal and/or sequence and/or segment data be written to the header of the first rank gfp frame extended field (among Fig. 9 A step 46 and 48 and abovely describe with reference to Fig. 5 B).Also generated the payload length designator of the first rank gfp frame.

In an embodiment of the invention, be extracted in needed other information of route client signal on the bearer network so that when generating the load carrying frame header information, use.

Be mapped in the payload of load carrying frame if surpass the first rank gfp frame of a carrying client business, then a plurality of first rank gfp frames are mapped in the payload zone of second level gfp frame.This second level gfp frame is mapped to the payload zone of bearer network frame subsequently by the mapper 18 shown in Fig. 8 A.

Segment processing also makes very large client signal and to be mapped in a plurality of gfp frame payload by segmentation, is mapped to load carrying frame payload zone after each gfp frame payload institute.Like this, single client's frame is segmented into a plurality of load carrying frames that are suitable for propagating on bearer network.

No matter whether gfp frame staging hierarchy according to the present invention has a still more a plurality of rank, and all mapped device 18 of the minimum rank of gfp frame staging hierarchy is mapped to the payload zone (step 50) of load carrying frame so that transfer out on bearer network by reflector 20.

A specific embodiment of the present invention uses the gfp frame of 2 grades of classification systems to come to provide adaptation layer to the carrying ethernet network, and it makes a plurality of different client signal payload to carry in carrying ethernet frame payload zone.This hypothesis client signal payload can be routed on the Ethernet bearing network along same paths, makes that it can be by multiplexing in same ethernet frame payload together.The gfp frame of each highest level of carrying in the ethernet frame can both carry follows the different communication type and/or from different clients' client signal, wherein different client signals can transmit in same ethernet frame.This can make that the transmission of little payload signal is more effective, such as the VoIP on the Ethernet.Customer network can be used ethernet communication protocol.In one embodiment, ethernet communication protocol is a Connection-oriented Protocol, and it can provide Ethernet wide area network carrying service.

In Fig. 8 B, node 22 is as the encapsulation point of client's business.Those skilled in the art think can provide one or more parts that comprise the function that encapsulates node 10 also can be used to provide the function of decapsulation node, for example, same the network equipment both can be encapsulated as bearer service with the client's business that enters the GFP adaptation layer, can carry out decapsulation on the contrary again.

In Fig. 8 B, the receiver 24 of node 22 receives bearer service signal (step 60).Each frame of 26 pairs of carrying signals that received of data processor is handled to determine whether its payload comprises the data (step 61 of Fig. 8 B) of following GFP communication protocol.For example, utilize in the execution mode of ethernet communication protocol, the header of each carrying ethernet frame is handled to determine whether the value in the ethernet type header fields has indicated the payload zone to comprise the data of following GFP communication protocol at bearer network.If, de-mapping device 28 decapsulation gfp frame (step 62) from the load carrying frame payload then.

26 pairs of gfp frames of subsequent data processor are handled determining according to the GFP header whether gfp frame comprises any channel, sequence or section designator (step 63), and payload is separated extraction (step 64).

Can handle to determine whether this sequence number has indicated gfp frame to comprise " n " payload section or " n " client's frame (step 68) in 1 to n the gfp frame payload sequence sequence indicators and one or more other gfp frame headers subsequently, if and have a channel indicator, then determine the channel that the client signal data are derived from.

If the payload of deblocking binding and layout is n section in the sequence of n section, then check to check and whether receive every other 1 to n-1 gfp frame payload and be stored in the buffer 30, if then take out other n-1 payload (step 70) from buffer 30 (or other suitable storage arrangements).If do not receive reorganization original series or the required every other frame payload of data structure, then the payload of n gfp frame also stored (step 72) in buffer 30.

If the frame that receives is not a n frame, then check to check whether n frame stored (step 66) in buffer 30.If not, then the frame that receives is stored (step 72) in buffer 30.

If receive the payload of n frame, then further check the payload (step 70) that whether has now received needed all n-1 frame of restore data sequence/reception to check.If then take out all previously stored payload (step 74).The payload back of taking out is by 32 reorganization (step 76) of data assembler.If the data of reorganization have also formed gfp frame, then check to check whether its payload zone also is GFP (step 61).If then handle the data that repeat until final reorganization and form client layer PDU (step 78).

In case recover client PDU from the bearer network signal, just can it be launched on customer network by customer network reflector 34.

When having sequence indicators in the extended field of GFP header, the node that its indication receives this gfp frame need recover the gfp frame payload of predetermined sequence to recover original client signal integral body.This or comprise that the once packed node 10 of reorganization is mapped to the original client signal frame sequence of GFP, perhaps recombination data with form another PDU (GFP or client signal, if client signal the encapsulation node or at intermediate node by segmentation).

In Fig. 8 B, if found sequence indicators, but payload is not to form by client layer PDU is carried out segmentation, then the content of decapsulation only needs to be cushioned fully the original PDU sequence that forms client signal to recover, shown in the dotted line between the step 68 among Fig. 9 B and 76.

If had channel indicator in the extension header of the gfp frame of decapsulation, then the data assembler will recover its client's channel that is derived from (being reassembled as the client PDU that is restored to correct client signal channel if all sections have been guaranteed in segmentation) from the payload that this frame is derived.Each client's channel signal is passed to reflector 34 so that transmission (it may relate to different communication protocol in embodiments of the present invention) forward in a suitable manner subsequently.

Client signal directly can be segmented into GFP or then gfp frame be carried out segmentation by whole client signal is mapped to gfp frame indirectly.

Those skilled in the art will recognize that modification and function equivalent that above execution mode of the present invention is described, the scope of claim will be read as and comprise this change to described execution mode, and this it will be apparent to those skilled in the art that.

Although above specific reference GFP communication protocol, any communication protocol that provides for realizing identical functions of the present invention can be provided, no matter whether be the standard variants of current standard GFP communication protocol.

Claims

1. method that makes customer data be suitable in communication system, transmitting, this method may further comprise the steps:

2. method according to claim 1, wherein, described carrying general framing procedure frame is mapped to the payload zone of protocol Data Unit of the employed communication protocol of bearer network of described communication system.

3. according to above any described method of claim, wherein, bearer network communication protocol comprises ethernet communication protocol.

4. according to any described method in the claim 1 to 3, wherein, bearer network communication protocol comprises connection-oriented ethernet communication protocol.

5. according to above any described method of claim, wherein, general framing procedure frame comprises header, and this header has the extended field of the sequence number of the fragmentation state that is configured to indicate its payload and payload section.

6. according to above any described method of claim, wherein, general framing procedure frame comprises header, and this header has the extended field of the channel logo that is configured to indicate its payload.

7. the segment data that on communication system, transmits of basis client's the method for recombinating, this method may further comprise the steps:

A plurality of load carrying frames of Generic Framing Procedure communication protocol are followed in reception;

The extended field of the header of each in described a plurality of load carrying frames is handled to determine whether it has indicated the fragmentation state of its payload and the sequence number of payload section;

If detect a plurality of sections of same client's frame, then

Handle described a plurality of frame to extract each payload section;

According to the described payload section described client's frame of recombinating.

8. method according to claim 7, this method are configured to provide assembles service, and described gathering service is used for and will arrives the higher rate port from the service integration than the low rate port, and this method may further comprise the steps:

From a plurality of a plurality of client's frames of following Generic Framing Procedure communication protocol that receive than the low rate port;

Each client's frame is mapped to the payload information zone of load carrying frame, and each load carrying frame is all followed Generic Framing Procedure communication protocol and is had the extended field of the channel number that is configured to indicate its payload.

9. method according to claim 6, this method is implemented on the node that is set to provide in the communication network of assembling service, described gathering service be used for from client's service integration of receiving than the low rate port to the bearer network of visiting by one or more higher rate port of this node, this method may further comprise the steps:

Receive client's frame from a plurality of than the low rate port;

Described client's business is mapped to the payload zone of one or more described client's Generic Framing Procedure communication protocol frame;

Wherein, when each client's general framing procedure frame being mapped to the payload information zone of load carrying frame, each load carrying frame of following Generic Framing Procedure communication protocol all has the extended field of the channel number that is configured to indicate its payload, and wherein, each carrying general framing procedure frame all is mapped to the payload zone of the protocol Data Unit of bearer network communication protocol.

10. method that produces the Generic Framing Procedure staging hierarchy, this method may further comprise the steps:

Wherein, caught the information that makes that the size of Generic Framing Procedure payload can remain unchanged after this frame is extracted in one or more field in the header of the general framing procedure frame that first frame is packaged into.

11. method according to claim 10, wherein, whether the Generic Framing Procedure header indicator has indicated also to remain in the mapping staging hierarchy when the general framing procedure frame stack is carried out decapsulation frame.

12. according to claim 10 or 11 described methods, wherein, described header indicator is provided at the indication that there is the general framing procedure frame that will extract in the N-1 level at the level n place of described staging hierarchy.

13. according to any described method in the claim 10 to 12, wherein, another designator in the payload header has been indicated and has been no longer included the general framing procedure frame that will extract, and the staging hierarchy of general framing procedure frame stops.

14. a method that recovers the customer data that uses above any one method and be suitable for transmitting in communication system, this method may further comprise the steps:

Node place in described communication system handles the frame that receives, to determine whether its payload comprises the frame of following Generic Framing Procedure communication protocol; And

If described payload is a Generic Framing Procedure communication protocol frame, then:

I) described payload is carried out decapsulation;

15. method according to claim 14, this method is further comprising the steps of:

One or more extended field of the header of the general framing procedure frame that each deblocking is taken on is handled, to determine whether to exist the Channel Identifier of the channel logo of indicating the described client signal that described payload was derived from.

16. according to claim 13 or 14 described methods, this method is further comprising the steps of:

17. method according to claim 16, this method is further comprising the steps of: if detected a plurality of sections of same client's frame, then

Described a plurality of frames are handled to extract each payload section;

According to the described payload section original payload of recombinating.

18. one kind comprises the equipment that is provided to realize one or more parts of the step in any described method in the claim 1 to 17.

19. an equipment, this equipment comprises:

Mapper, it is set to first frame is encapsulated into the Generic Framing Procedure payload zone of other second general framing procedure frame of next stage that is positioned at the Generic Framing Procedure staging hierarchy,

Wherein, in the header fields of the general framing procedure frame that first frame is packaged into, caught the information that makes that the size of Generic Framing Procedure payload can remain unchanged after this frame is extracted.

20. equipment according to claim 19, wherein, whether the Generic Framing Procedure header indicator has indicated also to remain in the mapping staging hierarchy when the general framing procedure frame stack is carried out decapsulation frame.