CN104518911A - MPLS (multi-protocol label switching)-TP (transport profile)-based PTN (packet transport network) fault detection method - Google Patents

Abstract

The invention discloses an MPLS (multi-protocol label switching)-TP (transport profile)-based PTN (packet transport network) fault detection method. On the basis of an MPLS-TP transmission architecture, loss of continuity of any pair of MEPs in one MEG is periodically monitored by means of initiative sending of CV packets to detect out unplanned connectivity among the MEGs, and the method is applied to error detection and protection switch. After one MEP receives a CCM message, whether information is correct or not is judged according to functional fields in the message so as to judge whether faults occur or not. IP (internet protocol)-based forwarding is omitted, an end-to-end OAM (operation administration and maintenance) function is added, unnecessary processing of three-layer IP is avoided, and improvement of MPLS-TP-based PTN fault treatment ability can be significantly facilitated.

Description

A kind of PTN fault detection method based on MPLS-TP

Technical field

The present invention relates to a kind of PTN fault detection method based on MPLS-TP, belong to data communication field.

Background technology

Along with the capacity of data service is increasing, the business granule exchanged in network is also increasing, circuit switching can not meet the needs of business development gradually, circuit switching is more and more obvious to the trend of packet switching, PTN (Packet Transport Network, Packet Transport Network) is exactly that realizing circuit exchanges to the good solution of packet switching.PTN(Packet Transport Network, Packet Transport Network) refer to a kind of optical transport network framework and concrete technology, the requirement of transport network for aspects such as operation maintenance management (OAM), protection and webmasters can be met.Technology common in PTN: MPLS (Multi-protocol Label Switching is called for short transport MPLS); it is a most important technology of current Packet Transport Network; at present by point-to-point develop into point-to-multipoint; if the technology of complexity like this is for carrier class network; need to supplement powerful OAM(Operation Administration Maintenance) in MPLS; the SLA crossed over cannot be realized, error protection and diagnosis.MPLS-TP and T-MPLS compares has larger change in OMA.T-MPLS reason ITU-T issues with G series standard form, such as, G.8114 define function and the mechanism of OAM.But due to the otherness of this standard and MPLS, not by IETF and conventional router manufacturer are accepted, and the MPLS of IETF is not suitable for again the requirement of transmission network really, therefore in use fault is more, relevant fault detection method must be proposed.

Summary of the invention

The technical problem that the present invention solves, by a kind of PTN fault detection method based on MPLS-TP, overcomes the deficiencies in the prior art.

Technical scheme of the present invention is: based on the PTN fault detection method of MPLS-TP; the method is transmitted on framework basis at MPLS-TP; CV bag initiatively sends; periodically monitor successional loss situation between any a pair MEP in a MEG; detect the connectedness of unplanned property between MEG, be applied to error detection occurs and protection conversion, object is that MEP is after receiving a CCM message; judge that whether information is correct by the function field in plan message, determine whether to break down with this.

Described detects that the connectedness of unplanned property between MEG refers to that the mistake detected between MEG is mixed into.

Described fault comprises following situations, and different defect situation can be distinguished by fields such as the MEG ID in PDU message, MEP ID and MEL:

1) connectivity is lost: similar and AIS, loses with object MEG and be connected;

2) connect fault: between reciprocity MEG, there is the cross interconnected of mistake, in transmitting terminal CC message, comprise MEG and No. MEP by mistake, if when receiving terminal MEG does not conform to MEP number, be judged as connecting fault;

3) unexpected MEP: the link that there is mistake between two MEP of same MEG inside, is judged to be unexpected MEP when No. MEP of the MEP received and setting is not identical;

4) the unexpected cycle: the PDU Priod field cycle received does not mate;

5) unexpected MEG grade: the MEG Level that the MEG Level information in the PDU received is expected with transmission is inconsistent.

Compared with the existing PTN fault detection method based on T-MPLS, MPLS-TP distinguishes maintenance entity ME, Maintenance Entity MEG, Maintenance Entity end points and Maintenance Entity intermediate point MIP in failure diagnosis, there is provided global function nested simultaneously, each intermediate node in LSP can be managed independently and safeguarded, also can process maintenance field nested with MEG, realize TCM function.The method eliminates IP-based forwarding, increases OAM(Operation Administration Maintenance) end to end, avoids the unnecessary process of three layers of IP, and this is very meaningful based on the PTN troubleshooting capability of MPLS-TP to lifting.

Accompanying drawing explanation

Fig. 1 is detection procedure figure of the present invention;

Fig. 2 is that MPLS-TP remote loopback performs schematic diagram.

Embodiment

Continuity detects and Connectivity Verification (CC/CV)

Initiatively sent by CV bag, periodically monitor successional loss situation (LOC) between any a pair MEP in a MEG, the connectedness (mistake is mixed into) of unplanned property between MEG can be detected, be applied to error detection occurs and protection conversion.Object MEP is after receiving a CCM message, judge that whether information is correct by the function field in plan message, determine whether to break down with this, can judge to comprise following several defect situation, different defect situation can be distinguished by fields such as the MEG ID in PDU message, MEP ID and MEL:

1) connectivity is lost: similar and AIS, loses with object MEG and be connected.

2) connect fault: between reciprocity MEG, there is the cross interconnected of mistake, in transmitting terminal CC message, comprise MEG and No. MEP by mistake, if when receiving terminal MEG does not conform to MEP number, be judged as connecting fault.

3) unexpected MEP: the link that there is mistake between two MEP of same MEG inside, is judged to be unexpected MEP when No. MEP of the MEP received and setting is not identical.

4) the unexpected cycle: the PDU Priod field cycle received does not mate.

5) unexpected MEG grade: the MEG Level that the MEG Level information in the PDU received is expected with transmission is inconsistent.

The PTN fault detect that the present invention is based on MPLS-TP can be divided into initiatively and passive two kinds of OAM patterns.

1. active OAM pattern

As shown in Figure 1, initiatively sent by CV bag, periodically monitor successional loss situation (LOC) between any a pair MEP in a MEG, the connectedness (mistake is mixed into) of unplanned property between MEG can be detected.Object MEP is after receiving a CCM message, judge that whether information is correct by the function field in plan message, determine whether to break down with this, can judge to comprise following several defect situation, different defect situation can be distinguished by fields such as the MEG ID in PDU message, MEP ID and MEL:

1) connectivity is lost: similar and AIS, loses with object MEG and be connected.

2) connect fault: between reciprocity MEG, there is the cross interconnected of mistake, in transmitting terminal CC message, comprise MEG and No. MEP by mistake, if when receiving terminal MEG does not conform to MEP number, be judged as connecting fault.

3) unexpected MEP: the link that there is mistake between two MEP of same MEG inside, is judged to be unexpected MEP when No. MEP of the MEP received and setting is not identical.

4) the unexpected cycle: the PDU Priod field cycle received does not mate.

5) unexpected MEG grade: the MEG Level that the MEG Level information in the PDU received is expected with transmission is inconsistent.

Generally detecting transmission cycle is 1 second, and performance monitoring transmission cycle is 100 milliseconds, and pretection switch transmission cycle is 3.33 milliseconds.When MEP does not receive the CC message of the other side in 3.5 cycles, regard as the other side MEP and lose continuity.Network management personnel is in service source and destination node energy CC function, and CV frame message just regularly can send between business two end node.

As shown in Figure 2, in the stream processing procedure that CCM frame is general, CCM frame is initiated by the CCM configuration module of MEP, and MEP initiatively OAM sending module generates and terminad transmission, and MIP forwards CCM.

2. passive OAM pattern, is realized by LBM and LBR message.After introducing loopback detection, the connected state of virtual Tunnel can be judged in the MEP of same levels.After being introduced into packet network, strengthening the function of ping, initiated as required by network management personnel, the connectedness between test MEP, bandwidth are handled up or detect bit-errors etc.Meanwhile, loopback detection can be used for multicast LSP, raises to multicast ETH-LB function at MEP, sends detect frame to all terminal MEP, and when promoter receives, to return frame be the basic connection situation judging multicast system.Internuncial detection can be carried out by the mode of loopback in an existing LSP.When connection establishment, source MEP initiates remote loopback order, and opposite end MEP is responded this LBM by LBR.Under far-end is in loopback mode, all messages except LBM all will return according to former road, and LBM continuation be delivered to by the CPU process of loopback MEP.Can Timeliness coverage network failure by carrying out loopback detection, sectional loop-back detects the concrete region that effective location fault can be helped to occur.

LT function is used for neighbours and detects or Topology Discovery, and after manager sends request message, all adjacent MEP return back message, plays identifications, judges whether online, the function such as retrieval, and maintaining adjacent relation table, obtains MIP or MEP sequence.Meanwhile, also can be used for the location of fault, when breaking down or produce Forwarding plane loop, MIP or MEP ordinal relation is different from expection, and the change of position relationship can provide essential information for fault location.

Claims (3)

1. the PTN fault detection method based on MPLS-TP; it is characterized in that: the method is transmitted on framework basis at MPLS-TP; CV bag initiatively sends; periodically monitor successional loss situation between any a pair MEP in a MEG; detect the connectedness of unplanned property between MEG, be applied to error detection occurs and protection conversion, object is that MEP is after receiving a CCM message; judge that whether information is correct by the function field in plan message, determine whether to break down with this.

2. the PTN fault detection method based on MPLS-TP according to claim 1, is characterized in that: the connectedness of unplanned property between MEG refers to that the mistake detected between MEG is mixed in described detecting.

3. the PTN fault detection method based on MPLS-TP according to claim 1, is characterized in that: described fault comprises following situations, and different defect situation can be distinguished by fields such as the MEG ID in PDU message, MEP ID and MEL:

1) connectivity is lost: similar and AIS, loses with object MEG and be connected;

2) connect fault: between reciprocity MEG, there is the cross interconnected of mistake, in transmitting terminal CC message, comprise MEG and No. MEP by mistake, if when receiving terminal MEG does not conform to MEP number, be judged as connecting fault;

3) unexpected MEP: the link that there is mistake between two MEP of same MEG inside, is judged to be unexpected MEP when No. MEP of the MEP received and setting is not identical;

4) the unexpected cycle: the PDU Priod field cycle received does not mate;

5) unexpected MEG grade: the MEG Level that the MEG Level information in the PDU received is expected with transmission is inconsistent.