CN101057459B - Handoff supports for networks having different link establishment protocols - Google Patents

Abstract

In a communication system in which a roaming node seeking network access among different networks which are implemented with different network interface layer protocols, handoff schemes are instituted whereby the node may freely move from one network to another with reduced levels of interruptions with respect to the network access. Prior to and at the onset of a handoff, the node receives an indication for the handoff. The indication may be embodied in various forms such as a signal message indicating a change of the SID (System Identification), NID (Network Identification), or PZID (Packet Zone Identification). Alternatively, the indication can be in the form of information straightforwardly included in a data packet sent to the roaming node prior to the handoff. As another alternative, the indication can be implemented as distinguishable message patterns sent to the node in which different message patterns can be sent by different networks supporting different network interface layer protocols.

Description

To thering is the handover support of network of different link establishment protocols

Require the priority of 35 U.S.C. § 119

The present invention requires on September 28th, 2004 to submit to, title is the U.S. Provisional Application the 60/614th of " A Method andApparatus for Handoff Support Fast Link Establishment Protocol ", the priority of No. 215, this provisional application has been transferred to its assignee, and is explicitly recited in this as a reference.

Technical field

The present invention relates in general to block data communication, more specifically, relates to the handover support of the network to having different link establishment protocols, wherein in each network, carries out conventionally need to carrying out these different link establishment protocols before any block data communication.

Background technology

No matter the worldwide interconnection of network makes geographic distance how can have access to quickly information.Fig. 1 shows the rough schematic view of the global link of the network representing with Reference numeral 20 that is commonly referred to internet.Internet 20 is a lot of networks with different hierarchical levels that link together in essence.IP (Internet Protocol) work that Internet 20 is issued according to IETF (internet engineering task group).The details of IP can find in the RFC being announced by IETF (internet draft) 791.

Being connected on Internet 20 is various independent networks, is sometimes called as LAN (local area network (LAN)) or WAN (wide area network) according to network size.Shown in Fig. 1 is some in such network 22,24,26 and 28.

In each network 22,24,26 and 28, can there is the various device that interconnects and intercom mutually.Example has the computer, printer and the server that are commonly referred to node, this be only list several.In the time that node exceeds himself network and communicates by letter via Internet 20, need to give this node distributing IP address.The distribution of IP address can be manual or automatic.The manual allocation of IP address can be carried out by for example network manager.More at large, IP address is distributed automatically by the private server in for example LAN or WAN.

Bright for instance.Suppose that node 30 in network 22 attempts to send packet to another node 37 in network 24.According to IP, each packet needs to have source address and destination address.In this case, source address is the address of the node 30 in network 22.Destination address is the address of the node 37 in network 24.

Very at large, before the network insertion such as such via Internet 20 other network of access, need to carry out point-to-point communication.Lifting another example illustrates.Suppose that the node 30 in network 22 is laptop computers.Laptop computer node 30 is access network 22 directly.For example, but laptop computer node 30 can arrive the NAS (network access server) 32 in network 22 via some other means,, by telephone line, wire modem is dialled.In this case, node 30 typically with network 22 in NAS (network access server) 32 set up PPP (point-to-point protocol) session.After this block data communication of setting up between node 30 and network 22, or the block data communication of setting up between node 30 and any other network via Internet 20, will be by wire modem and telephone line and exchanged.If modulator-demodulator continuously non-synchronously by telephone line sending and receiving signal, also must be by point framing correspondingly to be applicable to continuous asynchronous modem link in the cocommutative packet of telephone line.

The appearance of wireless technology allows node to leave the network of their initial registration and arrive another network.For example, return with reference to figure 1, node 30 can be wireless device, such as, PDA (personal device assistant), cell phone or mobile computer, instead of be for good and all wiredly connected to network 22.Radio node 30 can move to outside the border of its home network (home network) 22.Like this, node 30 can roam to field network (foreign network) 28 from its home network 22.For access network 28, or be connected to other network via Internet 20, typically, node 30 also with network 28 in NAS 33 set up PPP session.Communicating by letter between node 30 in this case and NAS 33 undertaken by airlink.And the cocommutative packet of link aloft also must be divided into frame, to meet the form of consulting during the PPP session between node 30 and NAS 33.

The major part of PPP is all described in the RFC 1661 and 1662 being announced by IETF.In fact, PPP is the consulting session of internodal a kind of exploration, during this session, before any network service flow, one group of mutual acceptable parameter options is found out and be finally concentrated into node according to authority (capability) and availability from resource each other.Because PPP session need to be set up conventionally before network insertion, so PPP is called as " network interface layer protocol " sometimes.But, conventionally also use other similar terms, comprise " link establishment protocols " and " layer 2 protocol ".Hereinafter, term " network interface layer protocol ", " link establishment protocols " and " layer 2 protocol " use interchangeably.

Fig. 2 shows the sequential flowchart of exemplary PPP communication session 34, and in this PPP communication session 34, the node 30 in network 28 is attempted to set up communication link with NAS 33, to can enter the Internet 20.

PPP has many agreement parts.In the exemplary PPP session shown in Fig. 2, PPP has LCP (LCP) 36, CHAP (challenge/Challenge-Handshake Authentication Protocol (Challenge/Handshake Authentication Protocol)) 38 and the IPCP (Internet Protocol configuration protocol) 40 as part.

First, completing after physical link, that is to say, can, after hardware layer arrives the other side, for example, need to experience LCP 36 at node 30 and NAS 33.LCP 36 for setting up basic communication link between node 30 and NAS 33.During LCP 36, node 30 and NAS33 exchange and consult necessary messaging parameter option mutually.These options can comprise, the largest amount of the packet by link, about whether being ready certified in the parameter of quality control, the HDLC using (control of a high level data link) field compression scheme and equity side.

The processing of LCP 36 is more or less to carry out according to the code of shaking hands.First, requesting party proposes one or more parameters by sending configuration request message.If recipient does not approve any parameter, recipient back makes response by configure-reject message.If unaccepted parameter plays a decisive role for the link of attempt foundation, requesting party has to stop PPP session.

On the other hand, if parameter approved, but the relevant option of this parameter is unacceptable, responder sends it back to configure and denies message (Configure Nak Message).Equally, requesting party can stop PPP session, or can send another configuration request message with the different options of same parameters.

As described above, all must be consulted in the above described manner and be determined with all parameters of relevant option.As shown in Figure 2, may need some negotiations of taking turns.If requesting party determines that all required parameters can be accepted for responder, final configure-ack message (Configure Ack Message) is sent to responder by requesting party.Once both sides have sent configure-ack message, they just forward authentication phase to.

All be authorized in order to ensure both sides, must carry out certification.A kind of mode of carrying out certification is to use another PPP part CHAP 38.Be typically, start CHAP38 and verify the identity of node 30 by NAS 33.During CHAP 38, NAS 33 sends to node 30 message that is called challenge message (challenge message).Under CHAP, exist a kind of shared secret using together with challenge message, it is used to carry out calculated response message with the algorithm of deciding through consultation in advance.Then, node 30 sends the response message generating by secret algorithm to NAS 33.After this, NAS 33 compares the response message receiving and the message of oneself being calculated by NAS 33.If comparative result mates, node 30 is called as and has passed through CHAP38, and wherein NAS 33 sends CHAP success message to node 30.Otherwise NAS 33 sends CHAP failed message.

Alternatively, can complete certification by PAP (Password Authentication Protocol (Password AuthenticationProtocol)) instead of CHAP 38.In PAP, node 30 only sends the user name and password for verifying to NAS33.If the verification passes, node 30 is called as and has passed through PAP.

If node 30 needs IP access, the informational needs of relevant IP exchanged and negotiation again.For example, especially, node 30 can need to be assigned to IP address, so that according to IP access 20 (Fig. 1).In order to realize this object, start to carry out negotiation and the exchange of parameter options according to IPCP 40.In exemplary PPP session 34, node 30 is at first to NAS 33 IP address requesting 0.0.0.0.As response, NAS 33 sends configuration and denies message, and suggested node 30 is used IP address a.b.c.d.If accepted, node 30 is confirmed the use of IP address a.b.c.d for the message of confirming by sending another to NAS 33.

Finally, during node 30 is agreed to IPCP 40 consult all parameters time, node 30 sends acknowledge message to NAS 33.After this, the user data of network insertion session is exchanged.The parameter that the IP packet utilization of Network had previously been consulted during LCP 36 is packaged in PPP frame.

In the time that network insertion finishes, node 30 or NAS 33 can send termination request message to the other side, and after this recipient makes and returns to response terminate communication sessions by terminate-ack message.

Can find out, during PPP session 34, between node 30 and NAS33, have considerable message exchanged from Fig. 2 and above description.So, the quite long duration will be there is.Consult PPP session 34 on the very large slow speed link of data delay time, especially such.

Set up processing for the initial link circuit accelerating between node 30 and NAS 33, proposed to be different from the variety of protocol of PPP.The title of submitting on July 28th, 2005 is the U.S. Patent application the 11/193rd of " Fast LinkEstablishment for Network Access ", in No. 068 (hereinafter referred to " ' 068 " patent application), announce the example of a this agreement.At this, quote clearly the whole content of ' 068 patent application that has transferred its assignee as a reference.Hereinafter, the link establishment protocols of any PPP of being different from is called as non-PPP.

But, in communication system, there is the non-PPP of some network supports and other networks are not supported the problem of non-PPP.When mobile node is in the time having the heterogeneous networks internetwork roaming of different link establishment protocols, this problem may be further complicated.

Lifting another example illustrates.Now directly referring back to Fig. 1.Suppose that node 30 is after moving to network 28, set up communication link via non-ppp session and NAS 33.Thereafter exchanging user data between node 30 and NAS 33.Further hypothesis is in the pilot process of exchanging user data, and node 30 moves to another network such as network 26.If in the various aspects that realize about physics and agreement, comprising network interface layer protocol, realizes on network 26, similar with network 28, and handoff scheme that can design flow line style.After arriving the field of network 26, network 28 can be by data processing transfer of responsibilities to network 26, and then network 26 can be taken over the block data communication function of previously being born by network 28.

But network 28 is conventionally different aspect realizing at hardware and link layer with 26.For example, hypothetical network 28 is not only supported PPP but also is supported another non-PPP as network interface layer protocol.On the other hand, network 26 only supports PPP as network interface layer protocol, and does not support other agreement.After network 28 is transferred to network 26, in order to continue network insertion, first node 30 need to set up another network interface layer protocol conversation with NAS 35 in network 26, like this, thereafter the block data communication of setting up meets the physical link of setting up between the NAS 35 in node 30 and network 26.If node 30 is not suitable for calling reposefully the required conventional P PP of network 26, node 30 may be completely severed network insertion.

Therefore, need to seek in the heterogeneous networks of supporting heterogeneous networks interface layer agreement for migration the node of network insertion, a kind of handover processing is reliably provided.

Summary of the invention

In the communication system with multiple networks, the node of seeking network insertion in communication system need to come from a Network Mobility to another network by handover processing.When different networks be realize with different network interface layer protocol time, there will be special problem.According to exemplary embodiment of the present invention, formulate handoff scheme, node can be in the case of less to the interruption of network insertion, from a netsurfing to another network thus.Before handover, node receives the instruction of handover.This instruction can be taked SID (system banner), NID (network identity) or PZID (packet zone mark) or their combination, the form of variant.Alternately, this instruction sends in the packet of node during can being directly included in handover.In addition alternately, this instruction can be taked the form of the massage pattern that sends to node, and wherein different massage patterns is sent by the heterogeneous networks of supporting heterogeneous networks interface layer agreement.

According to an aspect of the present invention, a kind of method is disclosed, wherein, the node of seeking network insertion passes through equipment, the method comprises the following steps: set up the first network interface layer agreement with service node, receive the instruction of handover, and the second network interface layer agreement of foundation and destination node.

According to a further aspect in the invention, a kind of hard-wired equipment with the step for carrying out above-mentioned disclosed method is disclosed.

According to another aspect of the invention, disclose a kind of computer-readable medium, this computer-readable medium has the computer-readable instruction of the step for carrying out above-mentioned disclosed method.

By reading following detail specifications by reference to the accompanying drawings, concerning professional and technical personnel in the field, these and further feature and advantage will be clearly, and the identical Reference numeral in accompanying drawing represents identical part.

Brief description of the drawings

Fig. 1 is the schematic diagram of the global link of network;

Fig. 2 is the communication sequence figure of the communication session of legacy network interface layer agreement;

Fig. 3 is the node that relates in general embodiment of the present invention and the schematic diagram of network;

Fig. 4 supports the node that relates in the exemplary embodiment of the present invention of wireless technology and the schematic diagram of network;

Fig. 5 is according to the schematic diagram of the protocol stack of hierarchical sequence;

Fig. 6 is the communication sequence figure of the communication session of the example networks interface layer agreement different from the legacy network interface layer agreement shown in Fig. 2;

Fig. 7 is the communication sequence figure of the step that in representing according to an exemplary embodiment of the present, the first handoff scheme of use relates to;

Fig. 8 is the flow chart of the handoff scheme of the communication sequence figure shown in Fig. 7;

Fig. 9 is the communication sequence figure of the step that in representing according to an exemplary embodiment of the present, the second handoff scheme of use relates to;

Figure 10 is the schematic diagram of the data frame format that uses in the network interface layer protocol of Fig. 2 and 6;

Figure 11 is the flow chart of the handoff scheme of the communication sequence figure shown in Fig. 9;

Figure 11 A is the flow chart of a variant of the handoff scheme of the communication sequence figure shown in Fig. 7;

Figure 12 is the communication sequence figure of the step that in representing according to an exemplary embodiment of the present, the 3rd handoff scheme of use relates to;

Figure 13 is the flow chart of the handoff scheme of the communication sequence figure shown in Figure 12;

Figure 14 is the schematic diagram of seeking according to an exemplary embodiment of the present invention the partial circuit of the node of network insertion;

Figure 15 is illustrated in service network to set up the communication sequence figure to the related step of objective network handover occurring in the process of network interface layer protocol conversation; With

Figure 16 is the flow chart of the handover processing shown in the communication sequence figure shown in Figure 15.

Embodiment

Below describe and be provided to make any professional and technical personnel of this area can both realize and use the present invention.Set forth for purposes of illustration in the following description details.Should be appreciated that, the those of ordinary skill of this area can be appreciated that, does not use these details still can realize the present invention.In other example, for fear of the details with unnecessary fuzzy description of the invention, will not describe known structure and processing in detail.Like this, the present invention and without wishing to be held to shown in embodiment, but consistent with the wide region that meets principle disclosed herein and feature.

Fig. 3 shows the node that relates in a general embodiment of the present invention and the rough schematic view of network.Whole communication system represents with Reference numeral 42, and communication system 42 comprises the network 45 and 47 that is connected to backbone network 49.Backbone network 49 can be Intranet or internet.Also can there is other network to be connected to backbone network 49, but brief for the sake of simplicity, also not shown in Fig. 3.

In network 45 and 47, be respectively arranged with NAS (network access server) 51 and 53, and they serve as the gateway of any node of seeking network insertion.Suppose to exist in system 42 and wish access network 45 or wish this node 55 via backbone network 49 other networks of access.Node 55 is access network 45 directly, but can communicate by letter with NAS 51 by communication link 57.Between node 55 and NAS 51, the preparation of communication is to carry out via the processing that is called as " link establishment ".

Suppose that node 55 is not limited in its primitive network such as network 45, and can be displaced to other network, such as network 47.

In this case, when node 55 deviated from network 45 and while moving on to network 57, for access network, node 55 must set up another link establishment session with NAS51 via another communication link equally in network 47.

Link 57 between NAS 51 and node 55 can be to take various forms of links.For example, link 57 can be wire link, and such as the connection of routine call line, coaxial cable link or cable link, this is only to enumerate several examples.In addition, link 57 can also be wireless link, for example, can deliver the air interface of electromagnetic signal or acoustical signal etc.

Fig. 4 shows a more concrete realization of the communication system 42 of supporting wireless technology.In this case, whole system briefly represents with Reference numeral 44.Internodal radio communication can be carried out via the link of air interface form, such as, the air interface links 58 and 90 shown in Fig. 4.In this embodiment, brief and concise for what illustrate, network 44 is illustrated as supporting the such wireless technology of cdma2000 standard such as being proposed by 3GPP2 (third generation partner program 2), and 3GPP2 is the alliance of several International Standards Organization of the TIA/EIA (telecommunications industry association/electronic industries association) that comprises the U.S..

In system 44, the node 56 that can roam into other network can be embodied as various forms, such as, PDA (personal digital assistant), mobile computer or cell phone, be only to enumerate several examples.

In network 46, realize PDSN (packet data serving node) 60, it carries out the function of NAS52.Node 58 is communicated by letter with PDSN 60 by RAN (Radio Access Network), and RAN wherein briefly represents with Reference numeral 62.RAN 62 comprises the BSC/PCF (base station controller/packet data control function) 64 that is connected to multiple BS (base station) 65A-65N.

Equally, in network 48, be furnished with another PDSN (packet data serving node) 66, it bears the responsibility of another NAS 54.Seeking the arbitrary node of network insertion communicates by letter with PDSN 66 by another RAN 68.RAN 68 comprises the BSC/PCF 70 that is connected to multiple BS72A-72M.

Network 46 and 48 can be processed the packet of delivery voice or data message.The title of announcing at 3GPP2 is " Interoperability Specification (IOS) for CDMA2000 Access Network Interfaces ", TIA-2001-D, can find the CONSTRUCTED SPECIFICATION of network 46 and 48 of supporting radio function in the document in February, 2005.

Before describing the details of operation of communication system 42, explain that first in general manner the correlation between processing and each agreement of the packet during the agreement of the various ranks via different layerings is carried out block data communication is helpful.

In network communications technology field, according to OSI (open system interconnection) model, by protocol hierarchy, osi model is to be proposed by ISO (International Organization for standardization) and ITU-T (International Telecommunication Union-telecommunication standard department).Target is the collaborative work ability that promotes multi-vendor equipment.That is to say, the protocol hierarchy of each rank has the specification of himself.Therefore, as long as meet the specification of particular hierarchical rank, the product of developing in this rank with regard to one surely with other rank in other products compatibility.

Suppose that the system 44 in Fig. 4 supports IP (Internet Protocol).Fig. 5 schematically shows according to the storehouse of multiple agreements of hierarchical sequence, is referred to as " protocol stack ", and briefly represents with Reference numeral 74.IP protocol stack 74 is configured to meet IETF (internet engineering task group) model, and this IETF model class is similar to osi model but is not identical.According to IETF model, IP protocol stack 74 has five layers, from layer 1 to layer 5.Like this, the packet that the each node in all nodes 56,60 and 66 as shown in Figure 4 sends out, must be through the processing of protocol stack 74.Protocol stack 74 is built in node with the form of software or hardware or the two combination.Equally, the packet that same node receives must, through the processing of same protocol stack 74, still be carried out according to contrary order.

Bright for instance.Tentation data grouping, through processing, sends from for example node of node 56 (Fig. 4), and first packet is to be that one of each agreement in layer 5 is created according to application layer.Layer 5 comprises HTTP (HTML (Hypertext Markup Language)), SMTP (service mail host-host protocol), FTP (file transfer protocol (FTP)) and RTP (RTP).Further tentation data grouping is the product of VoIP (internet protocol voice transmission) session.Therefore must be according to the RTP in layer 5 by data packet format.

The packet of time-sensitive, such as the packet producing according to the RTP in layer 5, need to process in real time.Particularly, conventionally do not resend the grouping of damage, but abandoned simply, to can not hinder the transmission of other packet on the horizon.Therefore, RTP packet is delivered via the UDP (user data packets agreement) in layer 4 (, transport layer) conventionally.

On the other hand, if packet comes from other agreement in layer 5, such as FTP, packet is sent out via the TCP in layer 4 (transmission control protocol) conventionally.In the situation that using TCP, the accurate transmission of packet is very important.Like this, although may reduce the speed of whole data sending processing, the grouping damaging is always resend.

Packet afterwards, is being added the information such as source port number and destination slogan through this transport layer (i.e. layer 4).

Packet, through transport layer (i.e. layer 4) afterwards, is then passed to network layer (i.e. layer 3) and processes.In this particular case, the packet generating in layer 4 must be formatd again according to IP, for example, and the source address of packet and destination address in interpolation.

Should be noted that for brevity, in Fig. 5, only show the IP in layer 3.In layer 3, also exist other agreement of IP being carried out to supplementary functions.An example is used to the ICMP (Internet Control Message Protocol) of the packet transmission error message that cannot transmit.

After this, packet must be divided into frame to meet the i.e. applicable any agreement in layer 2 of link layer.Previously described PPP (point-to-point protocol) is classified as layer 2 protocol.As previously mentioned, network can replace PPP as network interface layer protocol with other non-PPP.

The bottom of the protocol stack 74 in Fig. 5 is the i.e. layers 1 of physical layer, the physics realization of the transmission of its process data packets.For example, in Fig. 3, if communication link 57 is conventional wire links, physical layer layer 1 relate to node 55 and 51 that wire by forming link 57 the drives signal hardware circuit on the two.As another example, in Fig. 4, communication link 58 is air interfaces, and physical layer i.e. layer 1 and air space (air space) and relevant via the hardware circuit of the RAN 62 of air space receiving and transmitting signal.

Now return to Fig. 4 and with reference to this figure, the packet receiving for the node 56 by exemplary, packet must come by identical protocol stack 72 (Fig. 5) processed, but will be in reverse order, that is, processed to the order of layer 5 from layer 1.

Suppose in this example, originally node 56 is sought network insertion via PDSN 60.Further directly access network 46 of supposition node 56.

Traditionally, node 56 can start network insertion processing by first setting up PPP session with PDSN 60.But, as previously explained, in order to make link processing become pipeline-type, other network interface layer protocol is proposed before network insertion.Open in ' 068 patent application that one of this agreement exists, also as previously described.

In the following description, for convenience of explanation, describe to explain disclosed agreement in the patent application of ' 068 in conjunction with the operation of exemplary embodiment.But, should be noted that realization of the present invention does not need and should not be restricted to this situation.Can certainly apply other network interface layer protocol different from disclosed agreement in the patent application of ' 068.

Return to Fig. 4, before any message of exchange, physical link 58 must be ready to deliver signal.In other words, the physical layer of node 56 and BS 65A i.e. layer 1, must be first that physics exists and establishes.

Once physical layer is established, that is to say, the two detects that via RAN 62 the other side is that physics exists mutually node 56 and PDSN 60, PDSN 60 sends the first message to node 56 immediately.

Fig. 6 is the flow chart that represents the communication sequence of the message of transmitting between node 56 and PDSN 60.Whole flow processing represents with Reference numeral 75.In the patent application of ' 068, describe flow processing 75 in detail, and briefly this processing is summarized below.

PDSN 60 only accepts the network insertion of authorized node.The first message is sent by PDSN 60, and is called as synchronization message, represents with Reference numeral 76.Synchronization message 76 comprises all possible authentication option that can select for node 56.These options can comprise the challenge message according to CHAP (challenge authentication agreement), and for the required password of PAP (Password Authentication Protocol) and the request of user name, and applicable any other authentication protocol.

Receive after synchronization message 76, node 56 use request messages 78 respond, as shown in Figure 6.

Node 56 is put into the request that synchronization message 76 is proposed and is responded necessary authentication information in request message 78.In addition, node 56 is also put into and is set up node 56 and carry out subsequent network via PDSN 60 and access the required all parameter options of link used in request message 78.With the parameter of the option that is associated whether relevant with link configuration, certification or Network access control be do not have influential.That is to say, in request message 78, how all parameter functions with option are all placed into wherein, instead of according to about the function of the agreement part such as LCP (LCP), CHAP (challenge handshake authentication protocol) and IPCP (internet protocol control protocol) described in PPP, parameter being classified above.More specifically, those parameters with option in request message 78 can comprise the response to challenge message, or the user name and password (if applicable words), such as the link configuration parameter of the link 58 of datagram size and HDLC (High-Level Data Link Control) field compression scheme, and for the parameter of network insertion, such as IP address, DNS (domain name system) configuration and IP compression protocol (if applicable words) etc.Request message 78 is formatted as with intentional substantially in the redundancy aspect selection, so that the option that allows PDSN 60 to select node 56 and 60 all to support, thereby the promptly whole processing of end layer 2 links of permission node 56 and 60.In various selections, in order to increase the chance of successfully setting up link, PDSN 60 can optionally select the parameter with the relevant option being obviously supported, thereby shortens the whole link time.

As shown in Figure 6, be response request message 78, PDSN 60 sends response message 80.In response message 80, PDSN 60 selects option from various selections.Response message 80 comprises the parameter options of selecting with its relevant configuration value.Very at large, response message 80 is required last message before node 56 starts with the Network of the form of user data 82.In the time that network insertion finishes, node 56 or PDSN 60 can send and stop request message 84 to the other side, and then the other side goes back with 86 responses of terminate-ack message, and terminate communication sessions.

Different from other protocol method (all ppp protocols described above), before user data 82 starts exchange, what link processing 75 related in fact exchange messages negligible amounts.Thereby therefore the link layer i.e. link establishment of layer 2 can be completed more quickly.

Suppose in this example, with network 46 in the process of PDSN 60 exchanging user datas 82 in, node 56 starts to move to another network, such as network 48.Mobile route represents with the Reference numeral 88 shown in Fig. 4.

Under this sight, node 56 is substantially through being commonly referred to the processing of " handover ".More particularly, node 56 switches to from the PDSN60 connecting by RAN 62 network 46 PDSN 66 connecting by RAN 68 in network 48 by communication party.According to this embodiment, before handover, first node 56 needs to receive handover instruction.The various forms that handover instruction can be implemented with different schemes occurs.

Fig. 7 shows a kind of such scheme, briefly represents with Reference numeral 92.Refer now to Fig. 7, and in conjunction with Fig. 4.

Before handover, suppose that first node 56 carried out non-ppp link session 94 via RAN62 and PDSN 60 before any network of access.Session 94 can be the link establishment processing 75 that goes out as shown in Figure 6 and describe.The time period that non-ppp link is set up session 94 is for example, to last till t4 from t1.

It should be noted that PDSN 60 sends out LCP configuration request message 96 in the process of the non-ppp link session at time period t 2 places, this message 96 is PPP message.Its reason is, originally PDSN 60 does not know that node 56 is support conventional P PP or support non-PPP.In order to increase the chance that chains node 56, process 75 corresponding synchronization messages 76 (Fig. 6) and be sent out away according to the LCP configuration request message 96 of PPP with link establishment.In this case, node 56 supports link establishment to process 75.So, network interface layer protocol conversation 94 is carried out according to link establishment processing 75.

After network interface layer protocol conversation 94 is successfully set up, subsequently, can be at time period t 5 exchanging user datas 82.Suppose in this moment, node 56 starts to remove to network 48 from network 46.

According to cdma2000 standard, there is the network of radio function, such as network 46 and 48, constantly broadcast is to show their identity.Broadcast can be taked the form of " system parameters message ", sometimes also takes the form of " Extended System Parameters Message " of the upper delivery of F-BCCH (forward broadcast control channel), and wherein F-BCCH is one of forward control channel of network.So, such as the node of node 56, carry out the broadcast of automatic network by detection, always can find out its whereabouts.

In system parameters message, especially can find SID (system banner) and NID (network identity).SID is the number that is assigned to the specific wireless operator of network (such as, network 46 or 48).On the other hand, NID is the number that identifies uniquely the particular network in communication system (such as system 44).

In Extended System Parameters Message, comprise the PZID (packet zone mark) of the overlay area of mark PCF (such as, the BSC/PCF 64 or 70 shown in Fig. 4).If the communication system such as system 44 is supported HRPD (High Rate Packet Data), HRPD is wherein commonly called 1xEV-DO and is the wireless data technologies based on CDMA (code division multiple access), can find subnet ID (mark) instead of PZID from the subnet mask and the sector ID that are called as another broadcast of " Sector Parameter Message ".

Now return to Fig. 4 and 7, suppose that, in the time that node 56 arrives the field of network 58, node 56 receives the broadcast of automatic network 58.Wherein, broadcast shows new NID.New NID is different from previous NID.According to the change of NID, node 56 knows that it has moved to another network.Suppose in this example, network 48 does not support any non-PPP as its layer 2 protocol.So, the PDSN 66 in network 48 sends out LCP configuration request message 98.Now node 56 is made response to LCP configuration request message 98.Its reason is, because the change of NID, node 56 can reasonably suppose that it enters into new network, but does not also receive the non-PPP message such as synchronization message 76.On the contrary, received the LCP configuration request message 98 as PPP message.Node 56 is known newly arrived network immediately, such as network 48, does not support any unconventional layer 2 protocol.Thereby in time period t 8, node 56 makes rapidly himself to be oriented via ppp negotiation session 100 and holds consultation with PDSN 66.If success, subsequently at time t9 place exchanging user data 102, as shown in Figure 7.

It should be noted that node 56 makes response to the LCP configuration request message 98 of carrying out automatic network 48 in time period t 7, and the LCP configuration request message 96 of carrying out automatic network 46 in time period t 2 is not made to response.As mentioned above, this is because the time period t 6 of node 56 before time period t 7 learnt SID, the change of NID or PZID.

After successful execution ppp negotiation session 100, can set up user data 102.In the ending of user data 102, node 30 or NAS 33 can send and stop request message 104 to the other side, and the other side goes back with 106 responses of terminate-ack message in time period t 10 and t11 respectively subsequently, and terminate communication sessions 92.

The flow process of Fig. 8 there is shown according to the relevant step of the first handoff scheme of this embodiment.

Fig. 9 shows the alternative plan briefly representing with Reference numeral 108.Refer now to Fig. 4, and in conjunction with Fig. 9.Described in example above, node 56, via before serving PDSN 60 access networks, first passes through link protocol session 94.And larger in order to ensure the chance of hinged node 56, as previously described, during session 94, in time period t 2, PDSN 60 also sends LCP configuration request message 96.After the non-PPP network interface layer of successful execution protocol conversation 94, at time period t 4 exchanging user datas 82, as shown in Figure 9.And, suppose that, in user data 82 flow process, node 56 starts to move over to network 48 from network 46.In this example, node 56 receives handover instruction, and this instruction is different from the handover instruction of previous example.

Particularly, in the time that node 56 arrives the field of network 48, in the time period t 5 shown in Fig. 9, node 56 receives another LCP configuration request message 110.Now, the different messages ID (mark) that node 56 can be based in message 110 and 96, distinguishes the source of LCP configuration request message 110 with the LCP configuration request message 96 of time period t 2 of time period t 5, and this will below make an explanation.

At this moment, the data frame format that temporarily digresses from the subject to explain PPP message is helpful.

Figure 10 shows the have HDLC data frame format of (High-Level Data Link Control),---be similar to the framing format using in PPP.

Briefly represent with Reference numeral 112 for the frame template of packet, it is the grouping template specifying for 1662 times about the RFC of PPP substantially.More particularly, Frame 112 comprises tag field 114, address field 116, control field 118, protocol number field 120, data field 122, and FCS (Frame Check Sequence) field 124.

For back compatible PPP, want to replace most of network interface layer protocols of PPP to be also designed to have more or less and the similar frame format of frame format 112 of PPP.For example, in ' 068 patent application shown in Fig. 6, disclosed link protocol 75 can adopt and the similar frame format of frame format of PPP.

Now referring back to Figure 10.

Tag field 114 is a byte long, and the beginning of designation data packet frames.Tag field 114 is got hexadecimal value 7E always, and this same value is used to link processing 54 and PPP, as desired in RFC 1662.

Address field 116 is also a byte long, and is configured to hexadecimal value FF always, also described in RFC 1662.

Control field 118 is also a byte long, and is fixed to hexadecimal value 03, also as RFC 1662 defineds.

In protocol number field 120, what the value designation data grouping 112 in this field is.Protocol number field 120 is two byte longs.For example, as defined in RFC 1661 and 1662, the each message in LCP message, such as LCP configuration request message (Fig. 2), all has hexadecimal value C021.In order to distinguish between PPP message, deny message (Fig. 2) such as LCP configuration request message and LCP configuration, different messages ID is placed in data field 122, and this will make an explanation in the back.For other link protocol that is designed to replace PPP, disclosed agreement 75 in all ' 068 patent applications as shown in Figure 6, is used different protocol number 120, to separate with other PPP message area.For example, in the link processing 75 shown in Fig. 6, synchronization message 76, request message 78 or the response message 80 (Fig. 6) using in link processing 75 has and all different unique protocol values of any protocol value using in PPP.So, can easily distinguish packet 112 is that PPP grouping is also non-PPP grouping.

The length of data field 122 from zero in the scope of the more multibyte payload that comprises data or control information.For example, if the value in protocol number field 120 is values of LCP configuration request message 96 or 110 (Fig. 9) with designation data grouping 112, data field 122 comprises respectively and the messaging parameter option being necessary of setting up link 58 or 90 and being associated.As another example, if the value in protocol number field 120 has the value that designation data grouping 112 is user data 82 or 100 (Fig. 9), the IP packet generating from layer 3 by overall package to data field 122.

The length range of FCS field 124 is from two to four bytes, and comprises the code such as CRC (cyclic redundancy code), for frame 112 provides the basic protection that can avoid occurring between transmission period mistake.

Now return to Fig. 9 and with reference to this figure.As described above, data field 122 comprises message id, is called " code " under RFC 1661, and it distinguishes PPP type of message mutually, such as, between LCP configuring request and LCP configure-ack message (Fig. 2), distinguish.In identical type of message, also can further distinguish message id, for example, by the sub-ID of affix (being called " identifier " 1661 times at RFC).For example, can implement LCP configuration request message 96 and the LCP configuration request message 110 in the processing 108 shown in Fig. 9 with different code, or alternately, implement with identical code but by the different identifier characteristic of network.So, network 48 and 46 can be designed to, and by comprising different code or the identifier in the data field 122 (Figure 10) that is embedded in packet 112, sends out respectively different LCP configuration messages 96 and 110.Therefore, in this example, when node 56 moves past tense from network 46 to network 48, by recognize LCP configuration request message with identifier and network 48 different, node 56 is learnt in the field that lays oneself open to network 48.

In network 48 time, node 56 does not receive non-PPP message, but contrary, receives the LCP configuration request message 110 into PPP message, and according to the identifier different from LCP configuration request message 96, node 56 learns that network 48 do not support any non-PPP as its link establishment protocols.Node 56 makes rapidly oneself to be oriented response LCP configuration request message 110.Carry out as shown in Figure 9 subsequently ppp negotiation 100.Processing 92 shown in remainder and the earlier figures 7 of processing 108 is basic identical, no longer repeats here.

The flow process of Figure 11 there is shown according to the relevant step of the second handoff scheme of this embodiment.

Alternately, can be by the data field 122 of version/authority (version/capability) identification packet data inserting grouping 112.Under the cdma2000 standard of issuing at 3GPP2, can comprise version/authority identification packet, if the title at 3GPP2 is " Wireless IP NetworkStandard ", defined in the document of TIA-835D.Version/authority identification packet is the grouping of particular vendors substantially, and as implied in this title, the particular vendors of its mark manufacture node (all nodes as shown in Figure 4 56 or PDSN 60 or 66) for information about.Version/authority identification packet is mainly exchanged during the LCP stage of PPP session.The object of switch version/authority identification packet is, once each node of consulting has just been pointed out their version and authority in early days handling device through consultation, avoids during PPP session the unnecessary negotiation step about the not supported feature of both sides' node.

For instance, suppose that the node 56 in Fig. 9 receives the LCP configuration request message 96 with version/authority identification packet in time period t 2, version/authority identification packet wherein comprises the information of not getting rid of the possibility that uses non-PPP, thereby, node 56 time period t 3 not immediate recovery use PPP carry out link establishment.On the contrary, node 56 is proceeded non-ppp link in time period t 3 and is set up processing 94.On the other hand, if node 56 receives with the LCP configuration request message 110 of version/authority identification packet that only allows the information that uses PPP in time period t 5, then node 56 makes immediately oneself to be oriented at time period t 6 and consults via PPP and destination node 66.

Alternately, independently version/authority identification packet can be sent out away before LCP configuration request message 96 or 110.Like this, for example, can be sent by target P DSN 66 in 5, two message of time period t.As mentioned above, first message is the version/authority identification packet that includes particular vendor information in the data field 122 of packet 112 (Figure 10).Second message can be conventional LCP configuration request message, the LCP configuration request message during the LCP negotiation phase 36 of all PPP sessions 34 as shown in Figure 2.

The flow chart of Figure 11 A shows the relevant step of the handoff scheme of just having explained in the above.

Figure 12 shows another handoff scheme, briefly represents with Reference numeral 130.Refer now to Figure 12, and in conjunction with Fig. 4.The same with former scheme, when in network 46, node 56 need to carry out the link establishment session 94 with PDSN 60 before access network.And, larger in order to ensure the chance of hinged node 56, the time period t 2 during session 94, the PDSN 60 in network 46 also sends LCP configuration request message 96, as previously explained.It should be noted that now, LCP configuration request message 96 is to send in the centre of other non-PPP message of link establishment session 94.Successfully carrying out after non-PPP network interface layer protocol conversation 94, in time period t 4 to be similar to mode exchanging user data 82 aforementioned and as shown in figure 12.And, to suppose in the process of exchanging user data 82, node 56 starts from network 46 to network 48 roamings in the past.

In the time that node 56 arrives the field of network 48, now, as shown in figure 12, node 56 receives multiple LCP configuration request message 132A-132N in time period t 7.In this example, node 56 can be based on message sending mode, distinguishes in time period t 2 and comes the LCP configuration request message 96 of automatic network 46 and the source of carrying out the LCP configuration request message 132A-132N of automatic network 48 in time period t 7.More specifically, in time period t 2, node 56 receives a LCP configuration messages 96 among other non-PPP message of link establishment session 94.On the contrary, in time period t 7, node 56 receives multiple LCP configuration messages 132A-132N.

Like this, according to the receiving mode of LCP configuration request message, node 56 learns whether the network at node 56 current places supports non-PPP.For example, node 56 can be programmed to only the second continuous LCP configuration request message be responded.Like this, in this case, in time period t 2, in the time that node 56 receives LCP configuration request message 96, node 56 is waited for next message on the horizon.If next message on the horizon is not the repetition of LCP configuration request message 96, node 56 knows that network 46 supports are different from other non-PPP of PPP, and ignore simply LCP configuration request message 96 in time period t 2, and proceed as described above non-ppp link session 94.

On the other hand, if node 56 for example receives more than one continuous LCP configuration request message 132A-132N during time period t 7, node 56 is known the network that sends out message,, network 48, only supports PPP in the case and does not support other network interface layer protocol.Node 56 immediate recoveries become to communicate by letter with target P DSN 66 by the RAN 68 in network 48 via PPP, as shown in figure 12.The remainder of processing 130 is similar to aforesaid respectively in the processing 92 and 108 shown in Fig. 7 and Fig. 9 substantially, therefore no longer repeats here.

The quantity that it should be noted that the response to LCP configuration request message 132A-132N of being sent by node 56 is configurable.For example, replace as above embodiment described in the 2nd LCP configuration request message 132B after started to carry out ppp negotiation 100 with target P DSN 66 by node 56, node 56 also can start ppp negotiation 100 after i LCP configuration request message 132i, wherein the scope of i is from 2 to N, and N is greater than 2 integer.

The flow process of Figure 13 there is shown according to the relevant step of the 3rd handoff scheme of this embodiment.

Figure 14 schematically shows the hardware of the such equipment of all according to an exemplary embodiment of the present invention nodes 56 as shown in Figure 4 and realizes part, represents with Reference numeral 140.Equipment 140 can various forms structure and installment, such as, kneetop computer, PDA or cell phone, only give some instances.

Equipment 140 comprises the central data bus 142 that some electrical chains are connected together.These circuit comprise CPU (CPU) or controller 144, receiving circuit 146, radiating circuit 148 and memory cell 150.

If equipment 140 is parts of wireless device, reception and radiating circuit 146 and 148 can be connected to RF (less radio-frequency) circuit (not shown).The signal respectively receiving is processed and cushioned to receiving circuit 146, before the signal receiving is sent to data/address bus 142.On the other hand, radiating circuit 148, by before sending out equipment 140 from the data of data/address bus 142, is processed gentle data of bringing from data/address bus 142.The responsibility of the data management of CPU/ controller 144 executing data buses 142, also carries out the function of conventional data processing, comprises the command content of execute store unit 140.

Alternately, radiating circuit 148 and receiving circuit 146 can be parts for CPU/ controller 144, instead of arrange separately as shown in Figure 14.

Memory cell 150 comprises the one group of instruction briefly representing with Reference numeral 152.In this embodiment, instruction especially comprises the parts such as protocol stack function 154, link establishment client computer 156, link hand-off functionality 158 and ppp feature 160.Protocol stack function 154 operation with previously as shown in Figure 5 with the similar protocol stack of the storehouse 74 of describing.Link establishment client computer 156 comprises the instruction group for setting up the one or more link processing (processing 94 shown in above-mentioned Fig. 7,9 and 12) except ppp link is processed.Ppp feature 160 comprises for permission equipment 140 carries out the instruction group that PPP processes.Link hand-off functionality 158 comprise for carry out handover processing (such as, shown in relevant Fig. 7-13 and describe processing 92,108 and 130) instruction group.Ppp feature 160 can be used to the network of not only supporting PPP but also supporting non-ppp link processing independently, or does not support for subsequent use in the situation of other non-ppp link processing as network and used, also as described above.

In this embodiment, memory cell 150 is RAM (random access storage device) circuit.Exemplary instruction department 154,156,158 and 160 is software routines or module.Memory cell 150 can be bound to another memory circuitry (not shown), this another memory circuitry can be volatibility can be also non-volatile type.Alternately, memory cell 150 can be made up of other circuit types, such as, EEPROM (Electrically Erasable Read Only Memory), EPROM (EPROM), ROM (read-only memory), ASIC (application-specific integrated circuit (ASIC)), disk, CD and other circuit types well known in the art.

It shall yet further be noted that as Fig. 7-13 above, 15 and the 16 shown and processing 92,108 and 130 described, also can be encoded as the computer-readable instruction of carrying out on any computer-readable medium well known in the art.In this specification and claims, term " computer-readable medium " refers to any medium that participates in being provided for to the CPU/ controller 144 going out as shown in Figure 14 and describe the instruction of carrying out.This medium can be storage class, and can take as previously mentioned the volatibility of (for example,, in the explanation of the memory cell 150 in Figure 14) or the form of non-volatile memory medium.This medium can be transport-type, and can comprise can carrying machine coaxial cable, metal wire, optical cable and delivery sound wave or the electromagnetic air interface of readable or computer-readable signal.

Finally, described in this embodiment, handover step is for example shown in, in the process of exchanging user data 82 (, seeing Fig. 7,9 and 12) and carries out.But might not be by carrying out like this.When handover can occur in the process of node 56 in setting up network interface layer protocol conversation 94.Figure 15 shows this situation, wherein, in order to illustrate, go out as shown in Figure 7 and the link processing 92 described highlighted, and some relevant steps are repeated.As shown in the figure, in time period t 4, process before 94 completing link establishment, node 56, in move processing in the past to network 48 in, and is further perceived the change of SID, NID, PZID or subnet ID in time period t 4.So, node 56 may not receive the response message 80 of the PDSN 60 in automatic network 46 in moving process.But when in the time that time period t 5 nodes 56 receive LCP configuration request message 98, node 56 is learnt in the field that lays oneself open to network 48 and can be started immediately ppp negotiation processing 100 to be similar to aforesaid mode.In addition, this sets up equally for the processing 108 and 130 illustrating respectively in Fig. 9 and 12 and describe.That is to say, during not needing necessarily to occur over just exchanging user data according to the handover processing of exemplary embodiment of the present invention.In addition, system 44 has been described to support cdma2000 standard.Obviously other standard also can be applied.An example of other standard is the WCDMA (Wideband Code Division Multiple Access (WCDMA)) that 3GPP (third generation partnership project) issues.In addition, in the exemplary embodiment, layer 3 agreement are described to IP.IP can be different version, such as IPv4 (internet protocol version four) and IPv6 (IPv 6).In addition, it should be noted that and can apply equally other layer 3 agreements.For example, layer 3 agreement can be various other procotols of IPX (Internetwork Packet Exchange), Apple-Talk and different editions.In addition, any logical block, circuit and the algorithm steps described can be realized with hardware, software, firmware or their assembly in conjunction with the embodiments.Professional and technical personnel in the art should be appreciated that, without departing from the scope and spirit of the present invention, can make the change in these and other form and details at this.

Claims (4)

1. in communication system, mobile node is handed over to the method for destination node from service node, comprising:

Access described service node via first network interface layer agreement;

Receive the instruction of described handover, and

In response to the instruction that receives handover, access described destination node via second network interface layer agreement,

Wherein receive described instruction and comprise the multiple request messages that receive described second network interface layer agreement from described destination node, and

Wherein access that described service node comprises that mobile node sends for authenticating in a request message, one group of parameter options of link configuration and network insertion.

2. in the communication system of supporting IP (Internet Protocol), mobile node is handed over to the method for Section Point from first node, comprising:

Access described first node via the network interface layer protocol except PPP (point-to-point protocol);

Receive the instruction of described handover, and

In response to the instruction that receives handover, access described Section Point via described PPP,

Wherein receive described instruction and comprise multiple LCP (LCP) configuration request message that receives described PPP from described Section Point, and

Wherein access that described first node comprises that mobile node sends for authenticating in a request message, one group of parameter options of link configuration and network insertion.

3. the equipment in communication system, comprising:

For access the device of the service node of described communication system via first network interface layer agreement;

Be used for the device of the instruction that receives handover; With

For access the device of destination node via second network interface layer agreement in response to the instruction that receives handover,

Wherein said instruction comprises the multiple request messages from the described second network interface layer agreement of described destination node, and

Wherein access that described service node comprises that described equipment sends for authenticating in a request message, one group of parameter options of link configuration and network insertion.

4. the equipment in the communication system of supporting IP (Internet Protocol), comprising:

Via the device of the network interface layer protocol access first node except PPP (point-to-point protocol);

Receive the device of the instruction of handover, and

In response to receiving the instruction of handover via the device of described PPP access Section Point,

Wherein said instruction comprises multiple LCP (LCP) configuration request message from the described PPP of described Section Point, and

Wherein access that described first node comprises that described equipment sends for authenticating in a request message, one group of parameter options of link configuration and network insertion.