Background technology
The application of traditional private network, has promoted the growing of the performance of enterprises, but traditional private network is difficult to meet enterprise to netRequirement in terms of the flexibility of network, security, economy, autgmentability.This promotes a kind of generation of new alternative scheme,Traditional private network, that is, VPN (Virtual Private Network, Virtual Private Network) are simulated i.e. on existing IP network.
MPLS (Multi-Protocol Label Switch, multiprotocol label switching) is used as a kind of cost performance height and industryThe strong switching technology of business ability, can very easily realize the virtual private network business based on IP technologies, meet virtual specialWith net scalability and the demand of management.MPLS VPN have two ways：L2VPN and L3VPN.Wherein L2VPN is in MPLS netsThe Layer 2 data of transparent transmission user in network, L2VPN application technologies include VPWS (Virtual Private WireService, VLL service) and two kinds of VPLS (Virtual Private Lan Service, virtual privately owned LAN services).It is general to realize service bearer using VPWS in the Access Layer of wireless backhaul network.PW (Pseudowire, pseudo-wire) is operator's netNetwork provides the user a kind of implementation of VPWS services, in PE (Provider Edge, operator edge device) between PEA PW can be set up as public network tunnel, CE (customer edge) can so be connected with CE by PE, passed throughA plurality of PW, forms a LAN, so as to form a L2VPN to client.
The networking mode of PWE3 technologies be broadly divided into SS-PW (Single Segment Pseudowire, single hop pseudo-wire) andMS-PW (Multi-Segment Pseudowire, multi-segment pseudo-wires).SS-PW refers to the emulation end directly set up between two PETo end pseudo-wire, and MS-PW allows there is a plurality of PW between source PE and purpose PE, by SPE (switching equipment) by the SSPW of both sidesConnect, and on SPE complete PW aspects Tag switching.MS-PW meet network hierarchy, across LAN, cross operator,The application demand of trans-sectoral business control plane, lifts the expansibility of network.
SS-PW is that PW connections end to end are directly set up between two PE, directly passes through PW arrival pair during data forwardingPE is held, detection and positioning SS-PW are easier to realize.Equivalent to two PE of MS-PW are respectively created SS-PW with SPE and are connected, SS-By SPE realization order bearer connections between PW, it is also required to create SS-PW connections between multiple SPE, every two SPE if centre has.ButOn the PE of source, its SS-PW information between SPE is only known, it is not known that SS-PW relevant information behind SPE, so traditionalMode can not carry out detection of connectivity to MS-PW.
The content of the invention
For defect present in prior art, it is an object of the invention to provide a kind of inspection of multi-segment pseudo-wires network connectivtySurvey method, can realize MS-PW detection of connectivity using existing means.
To achieve the above objectives, the present invention takes a kind of multi-segment pseudo-wires network connectivty detection method, multi-segment pseudo-wires MS-PWNetwork includes the first operator edge device PE1 and the second operator edge device PE2, therebetween provided with multiple intermediate stationsPoint, at least one intermediate stations are switching equipment SPE, and methods described includes：
PE1 sends Ping detection messages, and its purpose PW-ID is final stage single hop pseudo-wire ss-pw in MS-PW network pathsID, is transmitted to PE2 successively through intermediate stations, and PE2, which is received, replys message to PE1 after Ping detection messages, PE1 is at the appointed timeThe message for receiving PE2 replies shows that MS-PW network paths are connected, otherwise path failure；
PE1 sends Tracert detection messages, and its purpose PW-ID is first paragraph ss-pw ID in MS-PW network paths, firstSecondary setting life span ttl value is that 1, Tracert detection messages often subtract 1 by an intermediate stations ttl value, when intermediate stations connectMessage is responded immediately to PE1 during to the Tracert detection messages that ttl value is 1, if intermediate stations now are SPE, according to previousSection single hop pseudo-wire ss-pw information finds out next section of ss-pw information, and renewal replies to PE1, and PE1 sends Tracert inspections next timeIt is next section of ss-pw ID to observe and predict literary purpose PW-ID, and ttl value setting Jia 1；If intermediate stations now are Tag switching routesP, P reply current site information and next hop information to PE1, and PE1 sends Tracert detection messages purposes PW-ID and is next timeCurrent ss-pw ID, and ttl value setting Jia 1.
On the basis of above-mentioned technical proposal, the PE1 fills Ping according to FEC 128 FEC-Target-TLV formsDetection messages.
On the basis of above-mentioned technical proposal, the Ping detection messages reach PE2, and PE2 is according in Ping detection messagesPW information find corresponding PW examples, then construct message reply to PE1.
On the basis of above-mentioned technical proposal, the ttl value of Ping detection messages is set to be more than all transmission roads of MS-PW networksFootpath hop count, often subtracts 1 by an intermediate stations ttl value.
On the basis of above-mentioned technical proposal, the Ping detection messages that the PE1 is sent include tunnel label and pseudo-wire markLabel, if the intermediate stations that Ping detection messages are passed through route equipment P for Tag switching, are replaced by after current tunnel label and turnHair；If the intermediate stations that Ping detection messages are passed through are SPE, more current changing after tunnel label and pseudo line tag is forwarded.
On the basis of above-mentioned technical proposal, if ttl value is more than 1 when intermediate stations are connected to Tracert detection messages, pass throughCross the intermediate stations and be forwarded to next intermediate stations, while ttl value subtracts 1.
On the basis of above-mentioned technical proposal, the PE1 is filled according to FEC 128 FEC-Target-TLV formsTracert detection messages.
On the basis of above-mentioned technical proposal, when SPE receives Tracert detection messages, according to purpose PW- thereinID finds current ss-pw information, and next section of ss-pw information is found out with this, and next section of ss-pw information includes ss-pw ID withTrip mapping downstream mapping.
On the basis of above-mentioned technical proposal, if PE2 receives the Tracert detection messages after intermediate stations forwarding, and rootJudge that PE2 is purpose website according to information is carried, then need not find out next hop information, directly reply message to PE1.
On the basis of above-mentioned technical proposal, if PE1 does not receive the reply message of some intermediate stations, or receive backMultiple message content mistake, then judge ss-pw failures residing for the intermediate stations.
The beneficial effects of the present invention are：It is MS-PW Ping and MS-PW that common pw ping/trace, which are expanded,Two parts of Tracert.It by Ping detection messages, can detect whether PW paths connect, help network engineering personnel analysisWith judge whether PW path failures.Pass through Tracert detection messages, it may be determined that packet each jump on PW pathsRouting information, can help network engineering personnel to analyze path and the positioning MS-PW failure websites of MS-PW networks；With reference to MS-PWThe two parts of Ping and MS-PW Tracert, can realize MS-PW detection of connectivity with existing means.
Embodiment
The present invention is described in further detail below in conjunction with drawings and Examples.
Multi-segment pseudo-wires network connectivty detection method of the present invention, is applied in MS-PW networks, including the first operator edge is setStandby PE1 and the second operator edge device PE2, therebetween provided with multiple intermediate stations, wherein at least one intermediate stations areSPE, it is preferred that PE1 is the start site of path detection, PE2 is the termination website of path detection.In order to clearly describe, thisTtl value is represented with ttl in invention, and the single hop pseudo-wire being referred to as in implication is expressed as in SS-PW, embodiment specific single hop pseudo-wire tableIt is shown as ss-pw.Multi-segment pseudo-wires network connectivty detection method includes two parts of MS-PW Ping and MS-PW Tracert, toolBody comprises the following steps：
MS-PW Ping parts, PE1 sends Ping detection messages, specifically, PE1 is according to FEC (ForwardingEquivalence Class, forwarding equivalence class) 128 FEC-Target-TLV forms filling Ping detection messages.Such as Fig. 1 institutesShow, be Target-FEC-TLV structural representations, wherein purpose PW-ID fillings are final stage lists in MS-PW network pathsActual section pseudo-wire ss-pw ID, Ping detection messages are mpls-echo-request detection messages.Ping detection messages are inBetween website transmit successively to PE2, it is preferred that set Ping detection messages TTL (Time To Live, life span) value be more thanAll transmission path hop counts of MS-PW networks, often subtract 1, i.e. ttl-1, ttl value by ttl value while an intermediate stations forwardingThe maximum hop count that really message can be forwarded in a network, intermediate stations receive the Ping detection messages that ttl value is 1, needMessage is responded immediately to PE1.PE2 is received after Ping detection messages, and the PW information in FEC-Target-TLV forms is looked forTo corresponding PW examples, then construct message and reply to PE1.
Specifically, pre-setting the stipulated time, if PE1 receives the message of PE2 replies at the appointed time, show MS-PW network paths are connections；If PE1 does not receive the message of PE2 replies at the appointed time, illustrate that MS-PW network paths go outExisting failure, will now be reminded in PE1 equipment to outbound path time-out.Wherein, Ping detection messages include tunnel label (outer layer markLabel) and pseudo line tag (vpn label), if the intermediate stations that Ping detection messages are passed through are P (Tag switching route equipment),It is replaced by after current tunnel label and forwards；If the intermediate stations that Ping detection messages are passed through are SPE, more current changes tunnelForwarded after road label and pseudo line tag.
MS-PW Tracert parts, PE1 sends Tracert detection messages, also according to FEC128 FEC-Target-TLV forms fill Tracert detection messages, and its purpose PW-ID fillings are first paragraph ss-pw ID in MS-PW network paths,Actual Tracert detection messages are also mpls-echo-request detection messages.Tracert detection messages are successively on MS-PW roadsTransmitted on footpath, often subtract 1 by ttl value while an intermediate stations forwarding.
If the intermediate stations for now receiving Tracert detection messages are SPE, according to previous in FEC-Target-TLV formsSection ss-pw information finds out next section of ss-pw information (including ss-pw ID and downstream mapping downstream mapping), andBy next section of ss-pw information solicitations FEC-Target-TLV and reply to PE1；PE1 is received with the message updated, you can to knowRoad ss-pw front and rear continuous relationship, also can be to detect next section of ss-pw using next section of ss-pw ID.PE1 is sent againPurpose PW-ID in Tracert detection messages, FEC-Target-TLV forms is next section of ss-pw ID, and the Tracert is examinedObserving and predicting text sets ttl value plus 1.
If the intermediate stations for now receiving Tracert detection messages are P (Tag switching routes), P is according to FEC-Target-Content in TLV forms, replys current site information and next-hop relevant information (downstream-mappingInformation PE1) is given, information of the PE1 in the message of reply describes all paths of MS-PW, and PE1 sends next timeTracert detection messages purposes PW-ID is current ss-pw ID, and ttl value adds 1.
In whole process, PE1 sends Tracert detection messages successively, and Tracert detection messages ttl values are set firstFor 1, i.e. ttl=1, it is 2,3,4 ... that Tracert detection messages ttl value is then sent every time, if what intermediate stations were receivedWhen Tracert detection messages ttl value is more than 1, then next intermediate stations are forwarded to by the intermediate stations, forwarding is while TTLValue subtracts 1；If the Tracert detection messages ttl value that intermediate stations are received is equal to 1, the intermediate stations need to respond immediately to reportText gives PE1.If PE2 receives the Tracert detection messages after intermediate stations forwarding, and is directly taken by Tracert detection messagesThe information of band judges that PE2 is purpose website, then need not find out next hop information, directly replys message to PE1.If PE1 does not haveThe reply message of some intermediate stations is received, or receives the message content mistake of reply, then judges ss- residing for the intermediate stationsPw failures.
As shown in Fig. 2 by taking a network topology as an example, including start site PE1 (Site IP is 1.1.1.9), termination stationPoint PE2 (Site IP is 5.5.5.9), intermediate node include P1 (Site IP is 2.2.2.9), SPE (Site IP is 3.3.3.9) andP2 (Site IP is 4.4.4.9).First paragraph path ss-pw ID are 100, and final stage path ss-pw ID are 200.P1 and SPEBetween path be ss-pw-01, between SPE and P1 path be ss-pw-02.
As shown in figure 3, MS-PW Ping parts comprise the following steps：
A101.PE1 sends Ping detection messages, and wherein purpose Site IP is to fill last in 5.5.5.9, purpose PW-IDOne section of ss-pw ID is 200, and the message content between PE1 and P1 is：Ttl value is ttl, and outer layer label is tunnel-01, interiorLayer label is ss-pw-01.
A102.Ping detection messages pass through P1, and the ttl value of Ping detection messages subtracts 1, i.e. ttl-1, due to being intermediate stationsP1, outer layer label is replaced by after outer layer label tunnel-02 by tunnel-01, and P1 continues to forward.
A103.Ping detection messages pass through SPE, and the ttl value of Ping detection messages subtracts 1 again, i.e. ttl-2, due to being middleWebsite SPE, behind will be continued by ss-pw-02 carrying, so outer layer label tunnel-02 is replaced by outer layer label tunnel-03, vpn label is replaced by ss-pw-02 by ss-pw-01, and SPE continues to forward.
A104.Ping detection messages pass through P2, and the ttl value of Ping detection messages subtracts 1 again, i.e. ttl-3 is intermediate stationsP2, therefore outer layer label is replaced by tunnel-04 by tunnel-03, P2 continues to forward.
A105.Ping detection messages reach PE2, checking prediction message, the SS-PW information in Target-FEC-TLV formsCorresponding PW examples are found, message is then constructed and replies to PE1.
A106.PE1 is received after reply at the appointed time, is illustrated all path connections of MS-PW, is echoed two-way time, returnsThe information such as multiple IP.
As shown in figure 4, MS-PW Tracert parts comprise the following steps：
B101.PE1 sends Tracert detection messages, and wherein purpose Site IP is that the is filled in 5.5.5.9, purpose PW-IDOne section of ss-pw ID is that the ttl value of 100, Tracert detection messages is 1, i.e. ttl=1.
P1 receives the detection messages that ttl value is 1, due to ttl=1, and current site is needed to respond immediately to, therefore P1 is found out downOne information jumped, i.e. downstream mapping (downstream mapping) reply message to PE1, and PE1 is received after the message of reply, returnAobvious first jumps routing information.
B102.PE1 continues to send Tracert detection messages, and wherein purpose Site IP is 5.5.5.9, filling ss-pw IDBe 2, i.e. ttl=2 for the ttl value of 100, Tracert detection messages, more than 1, therefore Tracert detection messages need by P1 afterContinuous forwarding, while ttl value subtracts 1, i.e. ttl-1=1.
SPE receives ttl=1 Tracert detection messages, the information such as PW-ID in Target-FEC-TLV forms,Current ss-pw is found, and then finds out next section of ss-pw information (ss-pw ID, downstream mapping), due toTtl value is 1, and current site SPE responds immediately to message to PE1, and PE1 receives echo second after SPE is replied and jumps routing information, especiallyNeed to echo SS-PW continuous relationships.
B103.PE1 continues to send Tracert detection messages, and wherein purpose Site IP is to fill out in 5.5.5.9, purpose PW-IDIt is 3, i.e. ttl=3 to fill the ttl value that second segment ss-pw ID are 200, Tracert detection messages, and P2 is transmitted to by P1, SPE,After forwarding that ttl value subtracts 1 every time, now ttl=1, P2 needs to find out the information (downstream mapping) of next-hop and returnedMultiple message is to PE1, and PE1 is received after P2 is replied and echoed three-hop path information.
B104.PE1 continues to send Tracert detection messages, and wherein purpose Site IP is to fill out in 5.5.5.9, purpose PW-IDIt is 4, i.e. ttl=4 to fill the ttl value that second segment ss-pw ID are 200, Tracert detection messages, is transmitted to by P1, SPE, P2PE2, after forwarding that ttl value subtracts 1 every time, now ttl value is that the information that 1, PE2 is directly carried according to FEC judges that our station is point of destinationPoint, the information (downstream mapping) without finding out next-hop, and message is directly replied to PE1, PE1 receives P2 repliesThe forth jump routing information is echoed afterwards, and terminates test, this time tests connective good.
The present invention is not limited to the above-described embodiments, for those skilled in the art, is not departing fromOn the premise of the principle of the invention, some improvements and modifications can also be made, these improvements and modifications are also considered as the protection of the present inventionWithin the scope of.The content not being described in detail in this specification belongs to prior art known to professional and technical personnel in the field.