CN101316272A - Multi-protocol layer interpretation method for constructing hybrid network of internet protocol version four and version six - Google Patents

Abstract

The invention discloses a multiple protocol layer translation method for establishing a hybrid network of Internet protocol versions 4 and 6 to solve the communication problem of the transition of the Internet towards an IPV6 network, which can effectively reduce capital input, improve information transmission efficiency, realize seamless exchange visits and smooth transition and establish the multiple protocol layer translation technique of the hybrid network. The MPLT technique consists of three basic constituent parts, namely, an address/port translation and conversion module at the lowest layer, protocol translation and conversion modules PT64 and PT46 at the middle layer, and an translation module of an application layer at the top layer, and through applying the multiple protocol layer translation technique MPLT in a proxy server that connects two types of networks, IPv4 and IPv6 and under the condition of not changing the original network topology, the three big problems of the network interconnection of different internetwork protocols are solved skillfully. The technique is characterized by fulfillment by layering, adding the flexibility and adjustability of a system through decomposing the function of translating two different network protocol data packets to various layers, and carrying out address/port conversion, protocol conversion and application layer conversion separately to extend flexibility.

Description

Make up the multi-protocol layer interpretation method of internet protocol version four and 6 hybrid networks

Technical field

Employing solves the communication issue of present the Internet to the IPV6 network transition based on IPV4 and IPV6 hybrid network construction method, can reduce capital invested effectively, improves information transfer efficiency, realizes seamless exchanging visit and seamlessly transits, and belongs to the network transition technical field.

Background technology

Internet protocol version four and 6 hybrid networks

Along with Internet develops rapidly, the network equipment and the operation application program thereon that insert Internet sharply increase, and have brought exhausting rapidly and problem such as routing table expansion of IP address thus, and be also extremely urgent to the expansion of IP address range.At the problem of IP address, IETF (Internet engineering duty group) has proposed iso-ip Internetworking protocol ISO-IP of new generation---and IPv6 agreement (IPv6 protocol), it has not only solved the address problem of IPv4, and has improved the performance of IP agreement.And in present stage, because Internet is based upon on the architecture of IPv4, all application programs are also according to the IPv4 format writing.Therefore how to become a new research focus to the transit mechanism of IPv6 transition and generation therefrom by IPv4.But since the successful use of IPv4 agreement nearly 20 years, quite ripe and have suitable scale based on the application program of IPv4 and equipment, all can not finish all overnight and upgrade and change.And on the other hand, that is that all right is ripe complete for the application program of IPv6 and equipment, will inevitably occur many isolated IPv6 networks like this.So how finishing the transition to IPv6 from IPv4, is the primary problem that solves of development IPv6.Thus in the long duration, communication between the IPv6 node also will depend on the facility of original IPv4 network, simultaneously the IPv6 node also must be indispensable will with the IPv4 node communication, so transition is inevitably, and transition will be distributed, progressive carrying out.

Following three phases will appear in the IPv6 at transition initial stage and IPv4 hybrid network: early stage, at this moment the IPv4 network accounts for main body, and the equipment of backbone network and the software of operation all are based on IPv4, and IPv6 is in initial launch and experimental stage.In mid-term, because the every performance of IPv6 is better than the IPv4 network, people begin to pay close attention to new technology, and adopt the new generation network architecture.In the later stage, every superior function of IPv6 network is known by people, and Large scale construction and superseded IPv4 network, makes the IPv6 network become the main body of the Internet.As shown in Figure 1.

The construction method general introduction

Construction method research will be found the communication issue way that solves between the hybrid network in transition period exactly, because IPv4 and IPv6 network are different network protocol layer, a series of network interconnection problems of being brought are as the datagram format problem of communicating by letter between hybrid network distributing IP address problem, addressing issue, domain name mapping problem, the hybrid network, packet crossing problem between heterogeneous networks etc.

Prior art scheme and defective thereof

1. dual-stack network

The dual-stack network technology is one of main method of hybrid network use in transition period.Move the main frame or the router of IPv4 and IPv6 protocol stack simultaneously as one in figure, support the network layer protocol of two versions of one-port.Router and main frame can obtain the communication capacity of node on IPv4 and the IPv6 network by the seamless link of two stacks, as shown in Figure 2.

The dual-stack network scheme is upgraded to the existing route node device, makes it become the IPv4/IPv6 router, and like this, the connection of IPv6 is a link-local just, is equivalent to IPv4/IPv6 and is present on the identical physical network.Two stack schemes need be distributed an IPv4 and an IPv6 address for each node on the network (comprising main frame and router).Dual-stack network does not need to purchase special IPv6 router and link, has saved hardware investment; Adopt special-purpose link-local between the core I Pv6 router, overcome many shortcomings of other modes.

The shortcoming of dual-stack network scheme is: can fight for bandwidth and router resource between the flow of IPv6 and the original IPv4 flow, thereby influence the performance of IPv4 network; Upgrading and maintenance cost are big, do not meet the strategy that begins evolution from network edge.At the initial stage of IPv6 networking, because the IPv4 address is sufficient relatively, the enforcement of this scheme has feasibility.Arriving certain phase when the IPv6 network development, is that each node distributes two overall situations

2. tunnel style

Tunnel style utilizes the tunnel to construct large-scale IPv6 network, and it is a kind of transition method commonly used at present.In essence, tunnel style is as a kind of transmission medium the IPv4 network.The scheme of utilizing tunnel style to realize is a lot, as manual configuration tunnel, auto-configured tunnel, 6to4,6over4, Tunnel broker and BGP tunnel etc.Tunnel style does not need a large amount of IPv6 dedicated router equipment and dedicated link, can reduce investment significantly, as shown in Figure 3.

The tunnel style shortcoming is: configuration of IP v6 tunnel is a cumbersome process on the IPv4 network, particularly when the tunnel number is increased to a certain degree, therefore, must carry out detailed document record when adopting the particularly manual tunnel of tunnel scheme; When fighting for bandwidth and router resource (CPU, buffering and routing table) between the flow of IPv6 and original IPv4 flow, the flow of IPv6 is less, and this problem is not clearly, but very outstanding in the future; The situation that has alternate route for entire I Pv4 network performance, is undoubtedly a kind of ill effect.At the initial stage of IPv6 networking, its network size and traffic carrying capacity are all less, and this is the connected mode that often adopts.

Summary of the invention

Technical problem: the purpose of this invention is to provide a kind of multi-protocol layer interpretation method that makes up internet protocol version four and 6 hybrid networks, mainly solve the technical problem of the connection between IPv4 and the IPv6 network.

Technical scheme: the constructing plan of hybrid network should be economical and practical, do not need the equipment of the new and old IPv4 network of great amount of investment, can be suitable for the general purpose conversion of IPv6/IPv4 again.There is the connection between connection between three phases problem: IPv6 and the IPv6 network, IPv4 and the IPv4 network in the present hybrid network, and the connection between IPv4 and the IPv6 network.The above two connection can realize by dedicated router, so the connection between IPv4 and the IPv6 network is the technical problem that we consider, as shown in Figure 4.

In view of hybrid network is formed in the network interconnection of two kinds of different networkings layer protocols, if will realize that transparent seamless link must solve: 1. domain name mapping problem; 2. map addresses problem; 3 header translation problems; This three classes problem.Multi-protocol layer translation technology MPLT is by three elements, and respectively at above problem, they are the address translation modular converter of the bottom, protocol translation modular converter PT64 and the PT46 and the top position application level translation module in intermediate layer.As shown in Figure 5.

Wherein the effect of address translation modular converter APT is the conversion that realizes source and destination address form in the IPv4 IPv6 packet header, the effect of two protocol converters, PT64 is converted to IPv4 with IPv6, PT46 is converted to IPv6 with IPv4, and the application level translation module realizes application such as hybrid network domain name mapping.Multi-protocol layer translation technology MPLT realizes by layering, two kinds of different network protocol packet Function Decomposition of translation increased the flexibility and the adjustability of system to each layer of agreement, so that address conversion, protocol conversion and application layer conversion are separately carried out.

Submodule and key technology

1. address is translated modular converter APT

Address transducer APT is a multi-protocol layer translation technology MPLT most important component, because it is responsible for the conversion of the network address and port.APT contains the information of active traffic.When packet arrived, its traffic authentication system of APT use found the map addresses of coupling, and map addresses is converted to corresponding address and port.If do not find the mapping that is complementary, APT can produce a new mapping according to corresponding rule.APT always changes in two different IPv6 address categories.

2. protocol translation modular converter

Two protocol translation modular converters---PT64 and the PT46 of multi-protocol layer translation technology MPLT are responsible for the address transition that realizes that between IPv4 and IPv6 packet and ICMP wrap.The packet header form of IPv6 and IPv4 data is closely similar, but and not quite identical.In another kind of version conversion process, need carry out certain adjustment at a kind of IP or ICMP version like this.IPv4 IPv6 heading is to such as Fig. 6, shown in Figure 7.

PT64 receives only the IPv6 packet that contains the IPv6/IPv4 mapping relations, and is similar with it, and PT46 then receives only corresponding IPv4 packet.Owing to being one to one between IPv6 address with mapping relations and the IPv4 address, protocol converter only need be set up a kind of mutual mapping for packet header and get final product between two kinds of agreements.When an IPv6 or the arrival of ICMPv6 packet, PT64 only need take out 32 minimum in IPv6 source of packets/destination address field (DAF) source/destination addresses that promptly can be used as corresponding IPv4 grouping.Equally, when an IPv4 or ICMPv4 packet arrived, PT46 only needs that the address field of grouping is added 96 locative preposition data can finish conversion from IPv4 to IPv6.

3. application level translation module

Because being based upon to connect between two main frames in the hybrid network, some application programs such as FTP etc. need know the other side IP address in advance, but what IPv4 node main frame sent to the IPv6 network all is " A " record, what the IPv6 node sent to the IPv4 network all is " AAAA " record, the application level translation module of MPLT is responsible for utilizing the IPv4 in self the reused address pool, IPv6 shines upon the address IPv6 that sends service request, the IPv4 address, give dns server then, realize the address lookup of spanning network, dns server feeds back to the middle-agent of operation MPLT with Query Result, is shone upon once more and is returned the requesting party by the MPLT middle-agent.

In the specific implementation process, on the boundary transition gateway of operation MPLS multilevel translation technology, safeguard a corresponding states table of depositing the right address pool of assignable IPv4, IPv6 address, port and IPv4, IPv6 address, port,

A. when the main frame of main frame in the IPV6 net and IPV4 network communicates:

1) datagram is sent to the gateway server that moves MPLS by the IPV6 network router, and MPLS receives

The IPv6 datagram, the address modular converter APT of MPLS checks at first whether its destination address is the IPv6 address of compatible IPv4, otherwise dropping packets; The IPv6 heading that with purpose is the IPv4 network then is converted to the IPv4 heading according to SIIT (Stateless IP/ICMP Translator),

The above bag payload of its transport layer remains unchanged,

2) search state table, if existing corresponding list item, the PT64 module is according to its mapping relations, IPv6 address and the port of replacing former message with IPv4 address in showing and port; Otherwise, from the IPv4 address pool of transfer gateway, distribute an IPv4 address and port, replace source messages IPv6 address and port, be the IPv4 address with the compatible IPv6 address transition of the IPv4 of source messages, finish the protocol conversion of IP layer message,

3) when the returned packet of IPv4 main frame arrives, table look-up, find corresponding IPv6 address and port, PT46 replaces its destination address and port, and its source address is converted to the compatible IPv6 of IPv4 address; If do not have corresponding list item, then dropping packets; So just finished whole transfer process,

B. when the main frame of main frame in the IPV4 net and IPV6 network communicates:

1) datagram is sent to the gateway server that moves MPLS by the IPV4 network router, and MPLS receives the IPv4 datagram, and the address modular converter APT of same MPLS checks at first whether its destination address is the IPv6 address of compatible IPv4, otherwise dropping packets; The IPv4 heading that with purpose is the IPv6 network then is converted to the IPv6 heading, and the above bag payload of its transport layer remains unchanged,

2) search state table, if existing corresponding list item, the PT46 module is according to its mapping relations, IPv4 address and the port of replacing former message with IPv6 address in showing and port; Otherwise, from the IPv6 address pool of transfer gateway, distribute an IPv6 address and port, replace source messages IPv4 address and port, be the IPv6 address with the IPv4 address transition of source messages, finish the protocol conversion of IP layer message,

3) when the returned packet of IPv6 main frame arrives, table look-up, find corresponding IPv4 address and port, PT64 replaces its destination address and port, and its source address is converted to the IPv4 address; If there is not corresponding list item, then dropping packets is finished transfer process,

C. the domain name mapping process in the hybrid network

1) the IPv6 main frame proposes the domain name mapping request to the IPv6 dns server;

2) the IPv6 dns server returns destination host IPv6 address to it, if the IPv4 network host then returns the compatible IPv6 of IPv4 address;

3) message received of IPv6 router parses is that the message of the compatible IPv6 of IPv4 address is routed to the MPLS gateway with destination address;

4) the MPLS gateway is finished the protocol headers conversion and the address change of IP message, and the message after the conversion is sent to the IPv4 network;

5) the IPv4 message that returns is routed to the MPLS gateway, revises and address transition through header, is routed to purpose IPv6 main frame.

Beneficial effect: the multi-protocol layer translation technology MPLT based on IPv4, IPv6 hybrid network is a kind of simply and efficiently hybrid network connectivity scenario.It can and only support to finish communication between the node of IPv4 at the node of only supporting IPv6, do not need to carry out any change on information source main frame and destination host, use simply, and the expense that drops into upgrading is low, and the legacy network topological structure be need not to change.MPLT can be by simple configuration to be used for finishing different conversions at different IPv4 with IPv6 address and protocol layer.Modular design and configuration expansion conveniently make the MPLT translation technology become the instrument of powerful network service.

Description of drawings

Fig. 1 hybrid network evolution figure,

The two stack mechanism figure of Fig. 2,

Fig. 3 tunnel model figure,

Fig. 4 MPLT application model figure,

Fig. 5 MPLT principle analysis figure,

Fig. 6 IPv4 heading figure,

Fig. 7 IPv6 heading figure,

Fig. 8 MPLT application level translation module map.

Embodiment

One, the design of address modular converter (APT)

1.APT function design

When a main frame need be got in touch with the external world, multi-protocol layer translation technology MPLT middle-agent server must be distributed to one in this main frame temporarily can be by the global address of outside identification.If when having a more than inner node that a global address need only be arranged with external relation simultaneously, then each independently connects and is all distributed a distinctive address binding temporarily, so that these internal nodes can be shared a global address.As for the IPv4 external network communication, IPv6 local area network (LAN) is assigned with some IPv6 addresses that can be mapped as effective IPv4 address (but need with the host number of external network communication often greatly more than these available address quantity) usually.The APT ways of addressing this issue is to make the multiple host in the IPv6 local area network (LAN) share an IPv6 address that comprises effective mapping relations.This is actually a kind of multiplexing of transmission identifier.During communication, the source address field of data packet header and port numbers are replaced by a special address binding, and this special binding relationship distributes by APT is interim.

With external network communication the time, APT not only will be responsible for using original address binding in the new address binding relationship alternate data grouping, and needs this substitutional relation of memory.When external network sends grouping, source address in APT will divide into groups and port numbers replace with new address binding; When receiving grouping, APT need replace the address field in the grouping return with the address binding of local area network (LAN) inside again.When APT receives an IPv6 packet, it comes primary flow ID in the alternate data bag with a stream ID that address mapping relation arranged, and the stream ID that shone upon binds source or destination address/port binding in the alternate data bag with other address.The config string of APT has determined the concrete processing procedure of this substitutional relation.Except that the dynamic assignment of above-mentioned discussion, APT also can handle the address conversion of some other simple form, as static address conversion and dynamic single address transition.

APT is different to coming from outside processing mode with packet internal network.APT is at the allocation of packets dynamic address mapping of certain orientation.The initialization stream of another direction can not carry out map addresses like this.OUTWARD PACKETS refers to by local network and sends, and purpose is the packet of internet (IPv4 or IPv6) main frame, and INWARD PACKETS is then opposite.APT has two input ports and two delivery outlets, is respectively applied for the reception and the transmission of OUTWARD grouping and INWARD grouping.APT receives packet from different input ports, through it being forwarded from different delivery outlets after the conversion again.

2. realize the APT of IPv4/IPv6 conversion based on IPv6

APT only receives and sends the IPv6 packet that contains the IPv6 address.Be the acting server that makes operation multi-protocol layer translation technology MPLT two kinds of patterns of process IP v4/IPv6 simultaneously, when when only supporting the main-machine communication of IPv4, multi-protocol layer translation technology MPLT server can distribute interim IPv4 address to give its inner IPv6 main frame.APT based on IPv6 supports the IPv6 address of IPv4 mapping to realize this purpose then for its inner IPv6 host assignment.

When multi-protocol layer translation technology MPLT server will be the IPv4 grouping with the IPv6 packet switched, APT was IPv6 address and the port numbers that mapping relations are arranged with the IPv4 address with IPv6 address and port mapping at first.And then this mapping address is converted to real IPv4 address, thereby realize that the IPv6 packet switched is the conversion of IPv4.The transfer process of grouping also similarly from IPv4 to IPv6.Earlier the IPv4 address transition is become the IPv6 address/port number with mapping relations, and then this address binding is converted into real IPv6 address and port numbers.

3. static mappings is shone upon with dynamic

APT can become a global address binding with the actual address and the port numbers of main frame.The static mappings function is meant that the address binding of internal network and the mapping relations between the binding of global address are static.For example, certain external address will be retained to indicate specific home address.Relative with static mappings, dynamically mapping only concerns the data flow reserved mapping of activity.

4. dynamic address mapping and dynamic address/port mapping

The dynamic address mapping is meant that APT only is external address mapping of internal host dynamic assignment, rather than an address binding.APT will directly use the address of shining upon to indicate this inner node, and replace primary flow ID with the stream ID that shone upon, in this mapping process, APT not only wants external address mapping of dynamic assignment, and original port numbers also will be mapped as new port numbers.Different with dynamic address/port mapping is that the dynamic address mapping just substitutes an address field in the packet header, and keeps other three parts among the stream ID.For outside packet, it replaces original source address field with mapping address; For inside packet, it replaces destination address in the grouping with the actual address of inner node, and this destination address is mapping address just.

Two, the design of protocol converter

Very important application of multi-protocol layer translation technology MPLT is to allow the node of IPv6 and the node of IPv4 to communicate.All to relate to the conversion of protocol conversion and address and port to a bag of IPv4 node transmission or its inverse process from the IPv6 node.PT64 is used to be connected based on the APT of IPv6 and to the grouping that needs are changed with PT46 and finishes protocol conversion.PT64 is used for the IPv6 bag of the local node of IPv6 is sent to the Internet nodes of only supporting IPv4.APT with source address and port form socket convert IPv4 mapping type IPv6 socket to.IPv6 head during PT64 will wrap convert the IPv4 head to and with the 32 minimum bits of IPv6 address as effective I Pv4 address.

Equally, IPv4 bag send to a node of only supporting IPv6 from a node of only supporting IPv4 need be through PT46 and APT to finish conversion.The prefix of PT46 by the source and destination address being added 96 bits to be converting IPv4 mapping type IPv6 address to, thereby convert the IPv4 head to the IPv6 head.APT enters the IPv6 address with purpose IPv4 mapping type IPv6 map addresses then.Because APT handles map addresses and distribution, PT64 and PT46 only are responsible for protocol conversion.Because modular design, so the realization of PT64 and PT46 is easily.After carrying out the packet protocol conversion, PT64 and PT46 need the verification of upper-layer protocol (for example TCP, UDP) and recomputate.TCP and UDP according to pseudorandom head calculate they verification and, this pseudorandom head comprises the source address and destination address, high-rise packet length and agreement (next head) field of (IP/IPv6).When from IPv6 when IPv4 changes, PT64 must calculate the needed IP verification of IPv4 head and.Yet, because the IPv6 head do not have verification and this field, PT46 do not need to calculate IPv6 verification and.

ICMPv6 and ICMPv4 verification with calculating on be different equally.PT46 must calculate ICMPv6 according to the pattern of TCP and UDP, because comprised the pseudorandom head in the calculating of ICMPv6.Yet, PT64 can be directly from the ICMPv4 bag calculate ICMPv4 verification and.In the process that ICMPv4IC and MPv6 change mutually, the difference of checksum value must be taken into account.

Three, application level translation Module Design

The application level translation module mainly solves the application software different instruction form at IPv4, IPv6 network two ends and the intercommunication issues for translation of record format, in application layer packet is handled, and finishes the conversion between IPv4 and the IPv6.Its design principle such as Fig. 8.By giving the different interpretive program of application level translation block configuration, can realize different application communicating by letter under IPv4 and IPv6 hybrid network environment in conjunction with the map addresses technology of lowermost layer.Use as common FTP, MPLT can be different with command format in the IPv6 network at IPv4 according to FTP behind the FTP interpretive program of packing into, in the top instruction transformation of finishing.

In the specific implementation process, on the boundary transition gateway of operation MPLS multilevel translation technology, safeguard a corresponding states table of depositing the right address pool of assignable IPv4, IPv6 address, port and IPv4, IPv6 address, port,

A. when the main frame of main frame in the IPV6 net and IPV4 network communicates:

A. datagram is sent to the gateway server that moves MPLS by the IPV6 network router, and MPLS receives the IPv6 datagram, and the address modular converter APT of MPLS checks at first whether its destination address is the IPv6 address of compatible IPv4, otherwise dropping packets; The IPv6 heading that with purpose is the IPv4 network then is converted to the IPv4 heading according to SIIT, and the above bag payload of its transport layer remains unchanged,

B. search state table, if existing corresponding list item, the PT64 module is according to its mapping relations, IPv6 address and the port of replacing former message with IPv4 address in showing and port; Otherwise, from the IPv4 address pool of transfer gateway, distribute an IPv4 address and port, replace source messages IPv6 address and port, be the IPv4 address with the compatible IPv6 address transition of the IPv4 of source messages, finish the protocol conversion of IP layer message,

C. when the returned packet of IPv4 main frame arrives, table look-up, find corresponding IPv6 address and port, PT46 replaces its destination address and port, and its source address is converted to the compatible IPv6 of IPv4 address; If do not have corresponding list item, then dropping packets; So just finished whole transfer process,

B. when the main frame of main frame in the IPV4 net and IPV6 network communicates:

D. datagram is sent to the gateway server that moves MPLS by the IPV4 network router, and MPLS receives the IPv4 datagram, and the address modular converter APT of same MPLS checks at first whether its destination address is the IPv6 address of compatible IPv4, otherwise dropping packets; The IPv4 heading that with purpose is the IPv6 network then is converted to the IPv6 heading, and the above bag payload of its transport layer remains unchanged,

E. search state table, if existing corresponding list item, the PT46 module is according to its mapping relations, IPv4 address and the port of replacing former message with IPv6 address in showing and port; Otherwise, from the IPv6 address pool of transfer gateway, distribute an IPv6 address and port, replace source messages IPv4 address and port, be the IPv6 address with the IPv4 address transition of source messages, finish the protocol conversion of IP layer message,

F. when the returned packet of IPv6 main frame arrives, table look-up, find corresponding IPv4 address and port, PT64 replaces its destination address and port, and its source address is converted to the IPv4 address; If there is not corresponding list item, then dropping packets is finished transfer process,

C. the domain name mapping process in the hybrid network:

The g.IPv6 main frame proposes the domain name mapping request to the IPv6 dns server;

The h.IPv6 dns server returns destination host IPv6 address to it, if the IPv4 network host then returns the compatible IPv6 of IPv4 address;

The message that the i.IPv6 router parses is received is that the message of the compatible IPv6 of IPv4 address is routed to the MPLS gateway with destination address;

The j.MPLS gateway is finished the protocol headers conversion and the address change of IP message, and the message after the conversion is sent to the IPv4 network;

K. the IPv4 message that returns is routed to the MPLS gateway, revises and address transition through header, is routed to purpose IPv6 main frame.

Claims (1)

1. multi-protocol layer interpretation method that makes up internet protocol version four and 6 hybrid networks, it is characterized in that multi-protocol layer interpretation method MPLT by three elements, they are the address translation modular converter of the bottom, the protocol translation modular converter and the application level translation module in intermediate layer;

In the specific implementation process, on the boundary transition gateway of operation MPLS multilevel translation technology, safeguard a corresponding states table of depositing the right address pool of assignable IPv4, IPv6 address, port and IPv4, IPv6 address, port,

A. when the main frame of main frame in the IPV6 net and IPV4 network communicates:

A. datagram is sent to the gateway server that moves MPLS by the IPV6 network router, and MPLS receives the IPv6 datagram, and the address modular converter APT of MPLS checks at first whether its destination address is the IPv6 address of compatible IPv4, otherwise dropping packets; The IPv6 heading that with purpose is the IPv4 network then is converted to the IPv4 heading according to SIIT, and the above bag payload of its transport layer remains unchanged,

B. search state table, if existing corresponding list item, the PT64 module is according to its mapping relations, IPv6 address and the port of replacing former message with IPv4 address in showing and port; Otherwise, from the IPv4 address pool of transfer gateway, distribute an IPv4 address and port, replace source messages IPv6 address and port, be the IPv4 address with the compatible IPv6 address transition of the IPv4 of source messages, finish the protocol conversion of IP layer message,

C. when the returned packet of IPv4 main frame arrives, table look-up, find corresponding IPv6 address and port, PT46 replaces its destination address and port, and its source address is converted to the compatible IPv6 of IPv4 address; If do not have corresponding list item, then dropping packets; So just finished whole transfer process,

B. when the main frame of main frame in the IPV4 net and IPV6 network communicates:

D. datagram is sent to the gateway server that moves MPLS by the IPV4 network router, and MPLS receives the IPv4 datagram, and the address modular converter APT of same MPLS checks at first whether its destination address is the IPv6 address of compatible IPv4, otherwise dropping packets; The IPv4 heading that with purpose is the IPv6 network then is converted to the IPv6 heading, and the above bag payload of its transport layer remains unchanged,

E. search state table, if existing corresponding list item, the PT46 module is according to its mapping relations, IPv4 address and the port of replacing former message with IPv6 address in showing and port; Otherwise, from the IPv6 address pool of transfer gateway, distribute an IPv6 address and port, replace source messages IPv4 address and port, be the IPv6 address with the IPv4 address transition of source messages, finish the protocol conversion of IP layer message,

F. when the returned packet of IPv6 main frame arrives, table look-up, find corresponding IPv4 address and port, PT64 replaces its destination address and port, and its source address is converted to the IPv4 address; If there is not corresponding list item, then dropping packets is finished transfer process,

C. the domain name mapping process in the hybrid network:

The g.IPv6 main frame proposes the domain name mapping request to the IPv6 dns server;

The h.IPv6 dns server returns destination host IPv6 address to it, if the IPv4 network host then returns the compatible IPv6 of IPv4 address;

The message that the i.IPv6 router parses is received is that the message of the compatible IPv6 of IPv4 address is routed to the MPLS gateway with destination address;

The j.MPLS gateway is finished the protocol headers conversion and the address change of IP message, and the message after the conversion is sent to the IPv4 network;

K. the IPv4 message that returns is routed to the MPLS gateway, revises and address transition through header, is routed to purpose IPv6 main frame.

Images