CN102256236A

CN102256236A - System and method for mobility management under separate mapping mechanism

Info

Publication number: CN102256236A
Application number: CN2011101527314A
Authority: CN
Inventors: 周华春; 易李; 洪毅清; 任飞; 张宏科
Original assignee: Beijing Jiaotong University
Current assignee: Beijing Jiaotong University
Priority date: 2011-06-08
Filing date: 2011-06-08
Publication date: 2011-11-23
Anticipated expiration: 2031-06-08
Also published as: CN102256236B

Abstract

The invention relates to a mobility management system and method under a separation mapping mechanism, which combines the network-based mobility protocol PMIPv6 with the separation mapping mechanism. In the access network of the separation and mapping network, the scheme has greatly improved the PMIPv6 protocol, and designed three functional entities: the access gateway, the control gateway and the data gateway, thereby realizing the separation of data forwarding and control signaling and the identity and location of the host Separation: By combining with the separation mapping mechanism, the separation of the access network and the core network is realized.

Description

Mobility management systems under a kind of separate mapping mechanism and method

Technical field

The present invention relates to the mobile management problem of network, particularly relate to mobility management systems and method under a kind of separate mapping mechanism.

Background technology

In early days in the Internet, the mainframe that communication node is fixed more often and places, main frame need not and can not move, this has also just caused, and the IP address is endowed dual semanteme when the traditional Internet architecture of design, the IP address is the identifier of host identities, and it is again the finger URL of expression mainframe network topology location simultaneously.

(Mobile IPv6 is current commonplace MIPv6) to mobile IP v 6, also is the internet mobility rwan management solution RWAN that comes into question maximum.Its design original intention is not change existing network infrastructure, supports for main frame provides to move.This characteristics that do not change network configuration make MIPv6 need main frame to participate in mobile management, MIPv6 and its network mobility agreement of deriving, two stack mobility protocols, many Care-of Address mobility protocol, and every kind of agreement corresponding security mechanisms is given mobile node (Mobile Node, MN) brought very big burden, the mobility signaling has taken finite wireless resources, (IP Security and Internet Key Exchange, IPSec/IKE) mode also is a kind of test to power consumption and the disposal ability of MN for the safety of MIPv6 acquiescence and cipher key change.

There are all drawbacks in actual applications in Host Based mobility management protocol, the researcher wants to give network side mobile management urgently, in August, 2005 internet engineering task group (Internet Engineering Task Force, IETF) NETLMM of Cheng Liing (Network-based Localized Mobility Management) working group has carried out comprehensive discussion for based on network mobility management mechanism, and in August, 2008 formally proposed proxy mobile IPv 6 (Proxy Mobile IPv6, PMIPv6).PMIPv6 is a kind of based on network mobility protocol, and not needing MN to make any change just can provide the mobility support for it.

The dual semanteme of internet-ip address is unfavorable for mobile management, and more corresponding for this reason agreements are devised to strengthen the mobile management of network.The identity of main frame and position separation mechanism are the research focuses in current internet field, can solve the dual semanteme of the IP address of the Internet preferably.Internet in 2005 the research task IRTF of working group (Internet Research Task Force) set up the RRG of route seminar (Routing Research Group) inquire into interconnection path by and address problem.Some famous schools and research institution have carried out a large amount of research and have proposed some tentative programmes in succession on separation mechanism in the world, and more famous scheme has: the LISP that the HIP that the HLP that the LANI that the eFIT that University of California in Los Angeles proposes, Massachusetts Polytechnics propose, University of California Berkeley propose, Ericsson propose, Cisco System Co. propose etc.

Prior art one related to the present invention

The network model of PMIPv6 agreement as shown in Figure 1.Agreement has been introduced two new functional entitys: Mobile Access Gateway (Mobile Access Gateway, MAG) and local mobile anchor (Local Mobility Anchor, LMA).MAG is at couple in router (Access Router, AR) go up realization, its major function is the access of detection MN and leaves, when MAG detects MN mobile, replace MN to carry out mobility management process, LMA with MN carries out the mutual of the relevant signaling of mobility, sets up or delete the communication tunnel between MAG and the LMA.(Home Agent, HA) similar, its major function is to safeguard the binding information of MN, guarantees the route accessibility of MN for the effect of LMA and the home agent among the MIPv6.

PMIPv6 is based on the mobility management protocol of network, does not need MN to participate in mobile management, can reduce to the complexity of portable terminal minimum.PMIPv6 allows the MN that mobility protocol is not installed to insert, and replaces MN to finish the process of mobile management by a MAG in the network.Because MN does not need to participate in to switch the Signalling exchange with the Binding Update process, thereby reduce the complexity of MN protocol stack, reduced the signaling consumption of air interface, the Radio Resource of preciousness when having saved the MN access network.

Itself is also embodying the thought that identity is separated with the position PMIPv6 agreement, in whole mobility management process, MN utilizes home network prefix (the Home Network Prefix of MAG clean culture, HNP), adopt the home address of the IPv6 form of IPv6 stateless configuration mode generation, in the PMIPv6 territory that MN inserts, this home address is used to unique sign MN identity.And the MAG that MN inserts is used to identify the current on-position of MN at the access address that Care-of Address is used as MN of acting on behalf of of network side.When MN switched to different MAG, its home address was constant, but variation has taken place in the current on-position of MN, and access address is also along with changing, and then mobile signaling protocol and user data will carry out addressing to MN by the new access address of MN.

The shortcoming of prior art one

PMIPv6 can only realize in the PMIPv6 territory that limited identity separates with the position, when the overseas main frame of MN and PMIPv6 communicates, packet from MN is sent to core net at the LMA place by decapsulation, packet is that home address with MN carries out route in fact in core net, rather than MN act on behalf of Care-of Address.This makes the position that the network attack person is easy to utilize the home address of MN to orient MN.

Side by side, the LMA of PMIPv6 is to handle the control gateway that moves the control signaling in mobility management process, is again the data gateway of transmitting the MN data, such design causes LMA to become single fault node in the PMIPv6 network configuration extremely easily, and reliability can't ensure.Though the NETEXT working group of IETF also has some draft discussion that the security mechanism of LMA is discussed, these schemes all can not fundamentally solve control gateway and the data gateway two-fold identity characteristic of LMA.

Prior art two related to the present invention

In order to solve the mobile management problem under the separation mechanism, the foreign scholar has proposed some its corresponding theory and specific design, and paper has proposed a kind of PMIPv6 and realized separating the mobile management of shining upon on the basis with the scheme of hostid agreement (HIP) combination.Also have relevant draft that PMIPv6 is discussed among the IETF and separate the scheme that mapping combines, individual draft has proposed a kind of PMIPv6 and position to be separated method that (LISP) combine and solves mobile management problem under the separation mechanism with identity.

The shortcoming of prior art two

Though these schemes are studied respectively with the mobile management problem under PMIPv6 combines separate mapping network, paper and draft all are from the angle of expansion PMIPv6, PMIPv6 has been discussed how has expanded to realize overall ambulant problem.Existing scheme is not all considered LMA data forwarding and the problem of controlling the signaling management multiplexing functions in the PMIPv6 framework.Paper is introduced the HIP structure, the more complicated of HIP agreement own, and need main frame that the HIP agreement is installed.Draft utilizes LISP to provide overall mobility for PMIPv6, but the LISP agreement adopts packaged type to handle from the user's data bag in core net, and does not consider data forwarding and control signaling management function separation mechanism.

Summary of the invention

For fear of above the deficiencies in the prior art, the present invention proposes mobility management systems and the method under a kind of separate mapping mechanism.Based on network mobility protocol PMIPv6 is combined with separate mapping mechanism, make full use of the advantage of separation mechanism and PMIPv6, redesigned a kind of separate mapping network that is fit to carry out mobile management more, new network has been realized three kinds of separation mechanisms simultaneously: promptly identity is separated with the position, data forwarding is separated with the control signaling, Access Network separates with core net.At above three kinds of separation mechanisms, the present invention introduced IAD (Access GateWay, AGW), control gateway (Control GateWay, CGW) and data gateway (Data GateWay, DGW).It is to realize that in Access Network (what be equal to PMIPv6 acts on behalf of Care-of Address Proxy-CoA, PCoA) mapping between for the home address of sign host identities and the access address that routable is used for identifying the MN current location that identity is separated with the position.Data forwarding is separated promptly by data gateway and control gateway with the control signaling, realizes data are transmitted and moved the management of control signaling respectively.Access Network separates with core net then to use for reference and separates mapping thought, and the home address of MN in the Access Network is mapped as in core net overall situation routable core address by address rewrite mechanism.Access Network is realized the access of various types of terminals; Core net then solves location management and route technology.

Purpose of the present invention is achieved through the following technical solutions:

Mobility management systems under a kind of separate mapping mechanism comprises in the Access Network:

At least one mobile node MN is used to connect access gateway AG W, and is registered to control gateway CGW, obtains mobility service;

At least one access gateway AG W is arranged at the Access Network edge, is used to monitor the access of mobile node MN and leave, and replaces MN and control gateway CGW to carry out the mutual of mobile signaling protocol, sets up the tunnel with data gateway DGW simultaneously, is responsible for the data forwarding of MN;

At least one control gateway CGW is used to realize the function of local mobile anchor LMA control plane, and carries out Signalling exchange between the AGW, and MN is carried out mobile management;

At least one data gateway DGW, on the one hand DGW is used for finishing the data forwarding function of the LMA of PMIPv6, is responsible for setting up communication tunnel with AGW, and DGW finishes the couple in router function of separate mapping network simultaneously;

Global map server GMS mainly finishes the core address of the overall situation and the map locating function between the home address of MN.

Motion management method under a kind of separate mapping mechanism, the concrete steps of this method are as follows:

Step 1:MN1 is connected to the AGW1 of Access Network, and AGW1 inserts detection to MN1, and according to the identity descriptor of MN1 MN1 is authenticated;

Step 2:AGW1 sends the positional information of agent binding update PBU with register update MN1 to CGW1, creates Binding Update list of entries BUL for MN1 simultaneously;

Step 3:CGW1 carries out dissection process to agent binding update messages, the MN1 that CGW1 judges registration whether for register first, Binding Update or separate registration; If registration first, for MN1 sets up the relevant information of a banding cache clauses and subclauses BCE with store M N1, with the source address in the PBU message, the address registration that also is AGW1 is the access address PCoA of MN1 simultaneously, and CGW1 is that MN1 selects a DGW and send the tunnel to set up request message then;

Step 4:DGW1 judges MN1 if insert first, then the core address of address pool dynamic assignment from local mapping server is used for carrying out map operation with the home address HNP of MN1, if home address and core address are mapping relations one to one, the mapping relations of home address and core address are write in the buffer memory of local mapping server; Simultaneously, DGW1 is sending to global map server GMS about the home address of MN1 and the mapping relations of core address in the buffer memory of local mapping server;

Step 5:DGW1 sets up the end of AGW1 to the tunnel of DGW1, and sends the tunnel acknowledge message to CGW1;

Step 6:CGW1 the tunnel of confirming the DGW1 end set up finish after, send agent binding to AGW1 and reply the PBA packet, also comprised home network prefix and mobile option that comprises the DGW address of MN1 among the PBA;

Step 7:AGW1 obtains available data gateway DGW1 address after receiving agent binding reply data bag, the two-way communication tunnel between foundation and the DGW1; AGW1 obtains the home network prefix of MN1 from PBA message, and with the mode of unicast of advertising of route RA home network prefix is announced to MN1, is used to simulate the home link of MN1; MN1 will allow situation according to the interface of MN1 after receiving advertising of route, uses the stateless address configuration mode to dispose the home address HoA1 of MN1;

Step 8:MN1 sends packet to the MNn that is positioned at Access Network 2 after obtaining home address HoA1; Here suppose that MNn has also finished above-mentioned steps 1-7, MNn is HoAn at the home address that Access Network 2 obtains, and packet at first is sent to AGW1;

Step 9:AGW1 encapsulates packet, and packet is sent to DGW1 by tunnel style, wherein the AGW1's of the PCoA1 current access of MN1 just acts on behalf of Care-of Address, DGW1_addr is the address of DGW1 in the Access Network side, encapsulation in this encapsulation process and the PMIPv6 territory is similar, has finished the mapping between home address HoA and the access address PCoA;

After step 10:DGW1 receives packet, at first it is carried out decapsulation, DGW1 carries out the inquiry of mapping relations then, this moment, DGW1 went up the core address of the HNP1 correspondence of having only MN1 of storage, then at first local LML1 is carried out the longest prefix match inquiry according to the source address HoA1 of packet, obtain qualified HNP1, obtain the mapping relations between HNP1 and the core address 1; Because DGW1 is the information of not relevant with HoAn routable core address n at this moment, DGW1 need carry out alternately with the global map server, obtains the core address n of HoAn correspondence by inquiry global map tabulation GML;

Step 11:DGW1 is after obtaining the core map addresses information of all HoA correspondences of packet, source address, destination address to packet shine upon replacement, and packet is sent to DGW2, this address replacement process has been finished home address and core map addresses in the separate mapping network;

After step 12:DGW2 receives packet, and do not know the HoA information of core address 1 correspondence, DGW2 at first to the HoA1 of global map server lookup core address 1 correspondence, separates mapping to source address, the destination address of packet then and replaces;

Step 13:DGW2 because set up and AGWn between the two-way communication tunnel, directly encapsulate packet this moment, and packet is sent to AGWn via the tunnel, DGW2_addr is the address of DGW2 in the Access Network side;

Step 14:AGWn carries out decapsulation to packet, and packet is sent to MNn;

Step 15:MN1 leaves the AGW1 of Access Network, and AGW1 leaves detection to MN1;

Step 16:AGW1 sends the agency to CGW1 and separates Binding Update, and the life span of MN is changed to 0, deletes the Binding Update list of entries of MN simultaneously;

Step 17:CGW1 separates binding update messages to the agency and carries out dissection process, if separate registration, the relevant information of deletion MN1 in banding cache clauses and subclauses BCE, CGW1 is that MN1 sends the tunnel deletion request message afterwards, the content of message comprises the address of MN1 place AGW1, just the home address of PCoA1 and MN1;

Step 18:DGW1 deletion in tunnel cache list TCE about the relevant entry of MN1, and the two-way communication tunnel between deletion AGW1 and the DGW1, unless there are other MN also using this tunnel, simultaneously, DGW1 informs the core address of LMS1 to MN1, the HNP mapping relations are deleted, and simultaneously the deletion of these mapping relations are informed to GMS;

Step 19:CGW1 sends the agency to AGW1 and separates binding response message PBA, and about the binding clauses and subclauses of MN1, and the two-way communication tunnel between deletion AGW1 and the DGW1 is unless there are other MN also using this tunnel among the AGW1 deletion Binding Update tabulation BUL.

The invention has the advantages that:

The present invention combines separate mapping network with based on network mobility protocol PMIPv6, realized three kinds of separation mechanisms: identity is separated with the position, data forwarding is separated with the control signaling and Access Network separates with core net.

Access Network adopts identity to separate with the position and based on network mobility management mechanism, and subscriber's main station does not participate in mobile management, has alleviated burden of main machine, is convenient to the mobile management plan implementation, is easy to realize functions such as many locals, stream mobility.

Dispose data forwarding and control signaling separation mechanism, can realize that Access Network can dispose a plurality of data gateways, control gateway is selected the different pieces of information gateway according to situations such as Access Network traffic load, eliminates data gateway performance bottleneck problem, reaches distributed mobile management purpose.

Access Network uses different addresses at Access Network and core net the user to be carried out route with the mapping mechanism of core net, realized separating fully of Access Network and core net, the user behavior that has guaranteed edge network does not influence core network, and the retractility of core network is strengthened.

Description of drawings

Fig. 1: PMIPv6 protocol theory figure;

Fig. 2: separation mechanism mobility management systems structure chart;

Fig. 3: separate mapping relations;

Fig. 4: mobile signaling protocol reaches data flowchart alternately.

Embodiment

Separation mechanism network of the present invention is divided into Access Network and core net, and the present invention has adopted a kind of improved PMIPv6 agreement at Access Network, has defined three new functional entity: access gateway AG W, control gateway CGW and data gateway DGW.Each Access Network is exactly a PMIPv6 territory.LMA among original PMIPv6 is broken down into two parts: CGW and is responsible for the processing controls signaling on function, DGW is responsible for transmitting user data.MAG function among original PMIPv6 then changes by AGW and realizes.The present invention adopts separate mapping mechanism between Access Network and core net, DGW realizes the mapping function of separating between Access Network and core net.To introduce ins and outs of the present invention from three aspects of mobile messaging form of separating mapping relations, functional entity and redetermination below.

1, separates mapping relations

The present invention is in order to realize the mobile management under the separation mechanism, and packet is separated mapping and realizes route in Access Network and core net, need use three class addresses: be used for unique identification MN identity home address, be used to identify the access address of the current on-position of MN, and be used for core address in the core net route.Three class address mapping relations logically as shown in Figure 3.

Home address is used for the identity of in the whole network unique identification MN.Access address is used to identify the current on-position of MN, and the data that mail to MN in Access Network will be routed to the position at MN place by access address.The core address only appears at core net, is used for to the route in the data realization core net scope of MN.As can be seen from Figure 3, the present invention has mainly adopted twice mapping, is respectively that access address (state step 9) as follows, and home address (is stated step 11) as follows to the mapping of core address to the mapping of address, local.The unique home network prefix HNP that wherein clearly stipulated among the PMIPv6 each MN correspondence among the RFC5213; MN is according to the HNP of correspondence, in conjunction with the stateless configuration mode, the home address of a MN of configuration (Home Address, HoA); Be that HNP acts in PMIPv6 and is equal to HoA, can both represent the uniqueness of MN, so use the HNP of MN to carry out the operations such as interpolation, inquiry, deletion of the mapping relations between home address and the core address in this patent.The result of twice mapping is, can carry out routing addressing at Access Network and core net respectively from the packet of subscriber's main station.

2, functional entity is divided

IAD (Access Gateway, AGW)

AGW is positioned at the Access Network edge, is equivalent to the MAG of PMIPv6 on the function, the access that detects MN with leave, different is that AGW only carries out the mutual of mobility signaling with CGW, the concrete form of signaling is with reference to PMIPv6.AGW needs to set up the tunnel with DGW simultaneously, is responsible for the data forwarding of MN.

Similar with the MAG of PMIPv6, AGW need safeguard the tabulation of Binding Update (Binding Update List, BUL), concrete data structure is shown in the Binding Update tabulation of table 1AGW, wherein PCoA1 is the access address of MN1, that expression inserts is AGW1; PCoA2 is the access address of MN2, and that expression inserts is AGW2; HNP1 is the local prefix of MN1, and HNP2 is the local prefix of MN2; DGW1 is that CGW is the data gateway address that MN1, MN2 distribute.

Table 1

Access address	Home address	The data gateway address
			PCoA1	HNP1	DGW1
PCoA2	HNP2	DGW1

Control gateway (Control Gateway, CGW)

CGW mainly finishes the control signaling management function of LMA among the PMIPv6 on function, be responsible for and AGW between Signalling exchange, the operations such as foundation, renewal or deletion of the bidirectional tunnel between AGW and the DGW are managed in the auxiliary mobile management of finishing MN simultaneously.CGW need safeguard the banding cache clauses and subclauses (Binding CacheEntrieCE) of a MN, concrete data structure is shown in the banding cache clauses and subclauses of table 2CGW, wherein MN identity descriptor is 48 bit medium access control address (the Medi a Access Control of AGW according to MN, MAC) length that converts to can reach the variable length string of 576 bits, as " mn1example " and " mn2example ", format character standardization network access identifier (Network Access Identifier, form NAI) of MN identity descriptor.

Table 2

MN identity descriptor	Access address	Home address	The data gateway address
				mn1example	PCoA1	HNP1	DGW1
mn2example	PCoA2	HNP2	DGW1

Data gateway (Data Gateway, DGW)

DGW can be divided into two parts on function: on the one hand, DGW finishes the data forwarding function of the LMA among the PMIPv6, is responsible for setting up communication tunnel with AGW, and the data flow that MN produces finally all is addressed to DGW.DGW therefore need to safeguard a tunnel cache entries tabulation (Tunnel Cache Entries, TCE), concrete data structure is shown in the tunnel cache entries of table 3DGW:

Table 3

On the other hand, DGW finishes the couple in router function of separate mapping network simultaneously, be equivalent to local mapping server (Local Mapping Server, LMS), the home address of local all MN of record, mapping relations between the core address, from the packet of MN when Access Network mails to core net via DGW, all to inquire about local map listing (the Local Mapping List on the LMS, LML), home address is replaced to corresponding core address, the concrete data structure of local map listing shown in the local map listing of table 4DGW, wherein core address 1 for LMS1 be MN1 distribute in core net routable core address; Core address 2 for LMS1 be MN2 distribute in core net routable core address.

Table 4

The core address	Home address
		Core address
1	HNP1
		Core address
2	HNP2

The global map server (Global Mapping Server, GMS)

The global map server of separate mapping network (Global Mapping Server, GMS) be deployed in core network, mainly finish the core address of the overall situation and the map locating function between the home address of MN, when packet mails to core net via DGW, GMS of packets need inquiry, GMS need safeguard a global map tabulation (Global Mapping List who comprises mapping relations between all home address of the overall situation and the core address, GML), concrete data structure shown in the global map tabulation of table 5GMS, wherein core address n be MNn place Access Network LMS be MNn distribute in core net routable core address; HNPn is the home address of MNn.

Table 5

3, mobile messaging formal definition

The new mobile messaging form of mobile management requirements of process definition of the present invention is defined as follows.

The agent binding that CGW sends to AGW in the mobile management is replied and need be carried the DGW address, the address packet of DGW is contained in the mobile option of a redetermination, form is shown in the mobile option of table 6DGW address, and style number wherein is 8 bit unsigned integer, needs IANA to distribute.Reserved field is 24 bit unsigned integer, and this field is initialized as 0 by the sender, and the recipient must ignore this territory.The DGW address field of 128 bits is used to store the DGW address that is used for data forwarding of being distributed to MN by CGW.

Table 6

The new mobile messaging subtype of the action needs such as tunnel foundation, renewal and deletion of mutual AGW and DGW definition between CGW and the DGW, this patent with reference among the PMIPv6 to the description of agent binding update form, defined new tunneled requests message format shown in table 7 tunneled requests message format, the style number of this mobile messaging needs IANA to distribute.Tunnel signaling sub-type field in this message is 8 bit unsigned integer.This patent has distributed following several values to tunnel signaling subtype: on behalf of the tunnel, 0 set up request; 1 represents the tunnel update request; 2 represent the tunnel removal request.Reserved field is 8 bit unsigned integer, and this field is initialized as 0 by the sender, and the recipient must ignore this territory.Identification field is 16 bit unsigned integer, is used to identify the identity of the sender of this tunneled requests signaling.

Table 7

Similar with the mobile option in the mobile IP v 6, this patent has defined the tunneled requests mobile option form in the tunneled requests message, shown in table 8 tunneled requests mobile option form.Sequence-number field is 16 bit unsigned integer, is used for judging whether what comprise be up-to-date tunneled requests signaling.The life span field is 16 bit unsigned integer, represents the life span of this tunneled requests signaling.The home network prefix length of MN is 8 bit unsigned integer, the prefix length of the home network of expression MN.Reserved field is 8 bit unsigned integer.The identity descriptor field of MN is 576 bits, is the unique identification of MN in this PMIPv6 territory.The home network prefix field of MN is 128 bits, and being specially and carrying CGW is the IPv6 home network prefix that MN distributes.The care-of address field of acting on behalf of of MN is 128 bits.The AGW that this field is carried the MN agency of trademark registration acts on behalf of the IPv6 address of COA interface index correspondence, with inform data gateway should and which AGW between carry out the associative operation in tunnel.

Table 8

The present invention has defined new tunnel acknowledge message form shown in table 9 tunnel acknowledge message form, and the subclass model of this mobile messaging needs IANA to distribute equally.Mode field is 8 bit unsigned integer, specifically following value can be arranged: 0 representative is asked successfully, if should be worth＞=128, then the mistake of unknown cause has appearred in expression.The tunnel confirms that sub-type field is 8 bit unsigned integer, specifically following value can be arranged: the affirmation that 0 representative is set up request message to the tunnel, 1 representative are to the affirmation of tunnel update inquiry information, and 2 representatives are to the affirmation of tunnel deletion request message.Sequence-number field is 16 bit unsigned integer, is used for judging that whether what comprise be that signaling is confirmed in up-to-date tunnel.The life span field is 16 bit unsigned integer, represents the life span of this tunnel affirmation signaling.MN identify label field is 576 bits, is the unique identification of MN.

Table 9

In conjunction with the mobility management systems Fig. 2 under the separate mapping mechanism, sending packet with the MN1 that is positioned at Access Network 1 to the MNn that is positioned at Access Network 2 is example, enter Access Network 1 from MN, to leaving Access Network 1, the basic procedure that mobile signaling protocol described in the invention reaches datum plane alternately as shown in Figure 4.

The home address of mobile node does not use in core net as overall routing address, can only use in the Access Network of access address PCoA under it and carry out route.When the mobile node MN in the Access Network 11 uses the mobile node MN n of HoA1 in Access Network 2 to initiate communication, signalling interactive process and data transmission procedure as shown in Figure 4, detailed step is as follows:

Step 2:AGW1 to CGW1 send agent binding update (Proxy Binding Update, PBU) with the positional information of register update MN1, for MN1 creates Binding Update list of entries BUL, as shown in table 1 simultaneously;

Step 3:CGW1 carries out dissection process to agent binding update messages, CGW1 judge the MN1 of registration be register first, Binding Update or separate registration.If registration first for MN1 sets up the relevant information of a banding cache clauses and subclauses BCE with store M N1, is registered as the source address in the PBU message (being the address of AGW1) the access address PCoA of MN simultaneously.CGW1 is that MN1 selects a DGW afterwards, is example here with DGW1, and sends the tunnel and set up request message, and concrete form is seen aforesaid mobile messaging formal definition;

Step 4:DGW1 judges MN1 if insert for the first time, then the core address of address pool dynamic assignment from local mapping server is used for carrying out map operation with the home address HNP of MN1, the present invention supposes that home address and core address are mapping relations one to one, and the mapping relations of home address and core address are write in the buffer memory of local mapping server.Simultaneously, DGW1 is sending to global map server GMS about the home address of MN1 and the mapping relations of core address in the buffer memory of local mapping server;

Step 6:CGW1 the tunnel of confirming the DGW1 end set up finish after, send agent binding to AGW1 and reply (Proxy Binding Acknowledgement, PBA) packet, home network prefix and a mobile option that comprises the DGW address of also having comprised MN1 among the PBA, concrete form is seen aforesaid mobile messaging formal definition;

Step 7:AGW1 obtains available data gateway DGW address after receiving agent binding reply data bag, the two-way communication tunnel between foundation and the DGW1.AGW1 obtains the home network prefix of MN1 from PBA message, and (Route Advertisement, mode of unicast RA) announces home network prefix to MN1, is used to simulate the home link of MN1 with advertising of route.MN1 will allow situation according to the interface of MN1 after receiving advertising of route, uses the stateless address configuration mode to dispose the home address HoA1 of MN1;

Step 8:MN1 can send packet to the MNn that is positioned at Access Network 2 after obtaining home address HoA1.Here suppose also completing steps 1-7 of MNn, MNn is HoAn at the home address that Access Network 2 obtains.Packet at first is sent to AGW1, and data packet format is shown in table 10MN1 to AGW1 data packet format;

Table 10

Destination address	Source address	Content
			HoAn	HoA1	Data

Step 9:AGW1 encapsulates shown in table 11AGW1 to DGW1 data packet format packet, and packet is sent to DGW1 by tunnel style, wherein the AGW1's of the PCoA1 current access of MN1 just acts on behalf of Care-of Address, DGW1_addr is the address of DGW1 in the Access Network side, encapsulation in this encapsulation process and the PMIPv6 territory is similar, has finished the mapping between home address HoA and the access address PCoA;

Table 11

Destination address	Source address	Destination address	Source address	Content
					DGW1_addr	PCoA1	HoAn	HoA1	Data

After step 10:DGW1 receives packet, at first it is carried out decapsulation shown in the packet format after the table 12DGW1 decapsulation.DGW1 carries out the inquiry of mapping relations then, this moment, DGW1 went up the core address of the HNP1 correspondence of having only MN1 of storage, then at first the source address HoA1 of packet is carried out the longest prefix match inquiry to local LML1, obtain qualified HNP1, obtain the mapping relations between HNP1 and the core address 1; Because DGW1 is the information of not relevant with HoAn routable core address n at this moment, DGW1 need carry out alternately with the global map server, obtains the core address n of HoAn correspondence by inquiry global map tabulation GML;

Table 12

Destination address	Source address	Content
			HoAn	HoA1	Data

Step 11:DGW1 is after obtaining the core map addresses information of all HoA correspondences of packet, source address, destination address to packet shine upon replacement shown in the data packet format after the table 13DGW1 mapping, and packet is sent to DGW2, this address replacement process has been finished home address and core map addresses in the separate mapping network;

Table 13

Destination address	Source address	Content
			Core address n	Core address	1	Data

After step 12:DGW2 receives packet, and do not know the HoA information of core address 1 correspondence, DGW2 at first to the HoA1 of global map server lookup core address 1 correspondence, separates mapping to source address, the destination address of packet then and replaces shown in the data packet format after table 14DGW2 separates mapping;

Table 14

Destination address	Source address	Content
			HoAn	HoA1	Data

Step 13:DGW2 since set up and AGWn between the two-way communication tunnel, directly encapsulate shown in the data packet format of table 15DGW2 to AGWn packet this moment, and packet is sent to AGWn via the tunnel, DGW2_addr is the address of DGW2 in the Access Network side;

Table 15

Destination address	Source address	Destination address	Source address	Content
					PCoAn	DGW2_addr	HoAn	HoA1	Data

Step 14:AGWn carries out decapsulation shown in the data packet format of table 16AGWn to MNn to packet, and packet is sent to MNn;

Table 16

Destination address	Source address	Content
			HoAn	HoA1	Data

Step 17:CGW1 separates binding update messages to the agency and carries out dissection process.If separate registration, the relevant information of deletion MN1 in banding cache clauses and subclauses BCE, CGW1 is that MN1 sends the tunnel deletion request message afterwards, and concrete form is seen aforesaid mobile messaging formal definition, and the content of message comprises the address (PCoA1 just) of MN1 place AGW1 and the home address of MN1;

Step 18:DGW1 deletion in tunnel cache list TCE about the relevant entry of MN1, and the two-way communication tunnel between deletion AGW1 and the DGW1, unless there are other MN also using this tunnel, simultaneously, DGW1 inform LMS1 to MN1＜the core address, HNP〉mapping relations delete, simultaneously the deletion of these mapping relations are informed to GMS;

Separation mechanism mobility back-up system as herein described is the major function entity with AGW, CGW, DGW, by a series of interacting messages between them, finishes the effective management to positions of mobile nodes, guarantees the correct foundation that communicates to connect.

Claims

1. A mobility management system under a separate mapping mechanism, characterized in that the access network includes:

At least one mobile node MN is used to connect to the access gateway AGW and register with the control gateway CGW to obtain mobility services;

At least one access gateway AGW, set at the edge of the access network, is used to monitor the access and departure of the mobile node MN, and replaces the MN with the control gateway CGW for mobile signaling interaction, and at the same time establishes a tunnel with the data gateway DGW, responsible for the MN data forwarding;

At least one control gateway CGW is used to implement the function of the local mobility anchor LMA control plane, perform signaling interaction with the AGW, and perform mobility management on the MN;

At least one data gateway DGW. On the one hand, the DGW is used to complete the data forwarding function of the LMA in PMIPv6, and is responsible for establishing a communication tunnel with the AGW. At the same time, the DGW completes the access router function of the separated mapping network;

The global mapping server GMS mainly completes the mapping query function between the global core address and the MN's home address.

2. A mobility management method under a separation mapping mechanism, characterized in that: the specific steps of the method are as follows:

Step 1: MN1 connects to AGW1 of the access network, AGW1 performs access detection on MN1, and authenticates MN1 according to the identity descriptor of MN1;

Step 2: AGW1 sends a proxy binding update PBU to CGW1 to register and update the location information of MN1, and at the same time create a binding update list entry BUL for MN1;

Step 3: CGW1 parses and processes the proxy binding update message, and CGW1 judges whether the registered MN1 is the first registration, binding update or de-registration; if it is the first registration, create a binding cache entry BCE for MN1 to store the relevant information of MN1 At the same time, register the source address in the PBU message, that is, the address of AGW1, as the access address PCoA of MN1, and then CGW1 selects a DGW for MN1 and sends a tunnel establishment request message;

Step 4: DGW1 judges that if MN1 accesses for the first time, it dynamically allocates a core address from the address pool of the local mapping server for mapping operation with MN1's home address HNP. If the home address and core address have a one-to-one mapping relationship, Write the mapping relationship between the home address and the core address into the cache of the local mapping server; meanwhile, DGW1 sends the mapping relationship between the home address and the core address of MN1 in the cache of the local mapping server to the global mapping server GMS;

Step 5: DGW1 establishes one end of the tunnel from AGW1 to DGW1, and sends a tunnel confirmation message to CGW1;

Step 6: After confirming that the tunnel at the DGW1 side has been established, CGW1 sends a proxy binding response PBA packet to AGW1. The PBA also includes the home network prefix of MN1 and a mobility option including the DGW address;

Step 7: AGW1 obtains the available data gateway DGW1 address after receiving the proxy binding response packet, and establishes a two-way communication tunnel with DGW1; AGW1 obtains the home network prefix of MN1 from the PBA message, and notifies RA with the route The unicast method will advertise the home network prefix to MN1, which is used to simulate the home link of MN1; after receiving the route announcement, MN1 will configure the home address HoA1 of MN1 in the stateless address configuration mode according to the interface permission of MN1;

Step 8: After MN1 obtains the home address HoA1, it sends a data packet to the MNn located in the access network 2; here it is assumed that the MNn has also completed the above steps 1-7, and the home address obtained by the MNn in the access network 2 is HoAn, and the data packet First sent to AGW1;

Step 9: AGW1 encapsulates the data packet, and sends the data packet to DGW1 through a tunnel, where PCoA1 is the proxy care-of address of AGW1 currently connected to MN1, and DGW1_addr is the address of DGW1 on the access network side. This encapsulation process Similar to the encapsulation in the PMIPv6 domain, the mapping between the home address HoA and the access address PCoA is completed;

Step 10: After DGW1 receives the data packet, it first decapsulates it, and then DGW1 queries the mapping relationship. At this time, only the core address corresponding to HNP1 of MN1 is stored on DGW1. First, according to the source address HoA1 of the data packet, the local LML1 conducts the longest prefix matching query to obtain qualified HNP1, and obtains the mapping relationship between HNP1 and core address 1; because DGW1 does not have the information of routable core address n related to HoAn at this time, DGW1 needs to communicate with the global mapping server Interact and get the core address n corresponding to HoAn by querying the global mapping list GML;

Step 11: After DGW1 obtains the core address mapping information corresponding to all HoAs of the data packet, it maps and replaces the source address and destination address of the data packet, and sends the data packet to DGW2. This address replacement process completes the separation and mapping of the home address in the network. Address and core address mapping;

Step 12: After receiving the data packet, DGW2 does not know the HoA information corresponding to core address 1. DGW2 first queries the global mapping server for the HoA1 corresponding to core address 1, and then demaps and replaces the source address and destination address of the data packet;

Step 13: Since DGW2 has established a two-way communication tunnel with AGWn, it directly encapsulates the data packet at this time, and sends the data packet to AGWn through the tunnel, and DGW2_addr is the address of DGW2 on the access network side;

Step 14: AGWn decapsulates the data packet, and sends the data packet to MNn;

Step 15: MN1 leaves AGW1 of the access network, and AGW1 performs departure detection on MN1;

Step 16: AGW1 sends a proxy unbinding update to CGW1, sets the MN's lifetime to 0, and deletes the MN's binding update list entry;

Step 17: CGW1 parses and processes the agent unbinding update message. If it is deregistration, delete the relevant information of MN1 in the binding cache entry BCE, and then CGW1 sends a tunnel deletion request message for MN1. The content of the message includes the AGW1 where MN1 is located address, which is the home address of PCoA1 and MN1;

Step 18: DGW1 deletes the relevant entries about MN1 in the tunnel cache list TCE, and deletes the two-way communication tunnel between AGW1 and DGW1, unless there are other MNs still using the tunnel, and at the same time, DGW1 informs LMS1 of the core address of MN1, Delete the HNP mapping relationship, and notify the GMS of the deletion of the mapping relationship;

Step 19: CGW1 sends a proxy unbinding response message PBA to AGW1, and AGW1 deletes the binding entry about MN1 in the binding update list BUL, and deletes the two-way communication tunnel between AGW1 and DGW1, unless other MNs are still using this tunnel.