CN105897451B

CN105897451B - OTN dispatching system and fault processing method

Info

Publication number: CN105897451B
Application number: CN201510038907.1A
Authority: CN
Inventors: 吴满全; 边德明; 毕胜; 敖萨日娜
Original assignee: China Mobile Group Inner Mongolia Co Ltd
Current assignee: China Mobile Group Inner Mongolia Co Ltd
Priority date: 2015-01-26
Filing date: 2015-01-26
Publication date: 2019-12-06
Anticipated expiration: 2035-01-26
Also published as: CN105897451A

Abstract

The invention discloses an OTN dispatching system and a fault processing method; the method comprises the following steps: detecting links between core layer core nodes carrying the PTN; wherein, the link between the core and the node is carried by at least two routing optical cables in the OTN; and when detecting that the link between the core nodes has a fault, switching the routing optical cable bearing the fault link. The invention can solve the problem that service protection can not be carried out when the L2VPN and the L3VPN simultaneously fail or the L3VPN fails in double points.

Description

OTN dispatching system and fault processing method

Technical Field

The present invention relates to communications technologies, and in particular, to an OTN scheduling system and a fault handling method.

background

when a Packet Transport Network (PTN) Network is used to carry a Long Term Evolution (LTE) service, a common networking topology of the PTN Network is a networking topology in a dual-uplink form, such as the networking topology in the dual-uplink shown in fig. 1, a core Layer PTN device, such as a signaling GateWay (sGW), and a backbone convergence device, such as an operator Edge device (PE), starts a three-Layer Virtual Private Network (L3VPN, Layer 3 Virtual Private Network), configures a two-Layer Virtual Private Network (L2VPN, Layer 2 Virtual Private Network) in an access convergence Layer, and carries and schedules the LTE service in a manner of L2VPN + L3 VPN; however, because the L2VPN and the L3VPN have different protection modes, there is no coordinated switching mechanism, and it is impossible to protect the service when the L2VPN and the L3VPN fail simultaneously or when the L3VPN fails in two-point.

Disclosure of Invention

the embodiment of the invention provides an OTN dispatching system and a fault processing method, which solve the problem that service protection cannot be carried out when an L2VPN and an L3VPN simultaneously fail or a double-point failure occurs in the L3 VPN.

the technical scheme of the embodiment of the invention is realized as follows:

the embodiment of the invention provides a fault processing method, which comprises the following steps:

detecting links between core nodes of a core layer carrying a Packet Transport Network (PTN); wherein links between the core nodes are carried by at least two routing optical cables in an Optical Transport Network (OTN);

and when detecting that the link between the core nodes has a fault, switching the routing optical cable bearing the fault link.

preferably, when detecting that a link between core nodes fails, the switching a routing optical cable carrying the failed link includes:

and when detecting that the common route or the overlapped route of the optical cable of the convergence layer of the PTN and the optical cable carrying the route of the link between the core nodes fails, switching the optical cable carrying the link between the core nodes from the optical cable carrying the failed common route or the overlapped route to the standby optical cable carrying the link between the core nodes.

when detecting that the links between a plurality of core nodes of the bearing core layer in the OTN simultaneously have faults, switching the fault links between the core nodes from the routing optical cable bearing the current fault links to the standby routing optical cable bearing the links between the core nodes.

preferably, the original protection set in the second layer virtual private network (L2VPN) and the third layer virtual private network (L3VPN) of the PTN is set with a switching delay; the method further comprises the following steps:

and when detecting that the link between the core nodes fails, triggering and switching the routing optical cable bearing the failed link prior to the original protection.

Preferably, links in two different directions corresponding to the core node are correspondingly carried by OTNs in two different planes, and power supplies of the OTNs are independently set;

the method further comprises the following steps:

and when detecting that the link corresponding to the core node in the first direction has a fault, scheduling the link using the core node in the second direction to transmit services.

The embodiment of the present invention further provides an OTN scheduling system, where the system includes:

A detection unit, configured to detect a link between core nodes of a core layer carrying a PTN; wherein links between the core nodes are carried by at least two routing optical cables in the OTN;

And the switching scheduling unit is used for switching the routing optical cable bearing the fault link when the link between the core nodes is detected to have the fault.

preferably, the detecting unit is further configured to detect that a common route or an overlapping route of a convergence layer optical cable of the PTN and a routing optical cable carrying a link between the core nodes fails;

the switching scheduling unit is further configured to switch the optical cable carrying the link between the core nodes from the routing optical cable to which the failed common route or the overlapped route belongs to the standby routing optical cable carrying the link between the core nodes.

preferably, the detecting unit is further configured to detect that links between multiple core nodes of a bearer core layer in the OTN simultaneously fail;

the switching scheduling unit is further configured to switch the faulty link between the core nodes from the routing optical cable carrying the current faulty link to the standby routing optical cable carrying the link between the core nodes.

Preferably, the original protection set in the L2VPN and the L3VPN of the PTN is provided with a switching delay;

the switching scheduling unit is further configured to switch the routing optical cable carrying the failed link prior to the original protection trigger when the detection unit detects that the link between the core nodes fails.

The detecting unit is further configured to detect that a link in a first direction corresponding to the core node fails;

The switching scheduling unit is further configured to schedule a link transmission service in the second direction using the core node.

In summary, in the embodiment of the present invention, to solve the problem that service cannot be protected in a multi-point failure scenario due to different protection manners in the L2VPN and the L3VPN without a coordinated switching mechanism, a core link of the PTN system that carries the LTE service is carried on the OTN, and at least two optical routing cable carrying links are arranged between core layer core nodes; therefore, when the link between the core nodes fails, the OLP switching process can be scheduled, that is, the link is switched from the failed routing optical cable to the non-failed standby routing optical cable, so that the OLP switching process is realized, and the normal transmission of the service is ensured.

Drawings

fig. 1 is a first scenario diagram illustrating a link failure according to an embodiment of the present invention;

FIG. 2 is a diagram illustrating a second scenario of a link failure according to an embodiment of the present invention;

fig. 3 is a third schematic view of a link failure in the embodiment of the present invention;

fig. 4 is a schematic diagram illustrating a routing optical cable configured to implement OLP switching processing in an embodiment of the present invention;

FIG. 5 is a schematic flow chart illustrating an implementation of a fault handling method according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of an OTN scheduling system in the embodiment of the present invention.

Detailed Description

The inventor finds out in the process of implementing the invention that: when a PTN network is adopted to bear LTE service, how to protect the service when the L2VPN and the L3VPN simultaneously fail or the L3VPN has double-point failure, and an effective solution is not available in the related technology; the following is a detailed description of the above problems:

as shown in fig. 1, at the boundary between an L2VPN and an L3VPN (corresponding to PE 1-PE 8 in fig. 1), the device is a PTN network core layer or backbone convergence layer device, the device terminates L2VPN traffic from a PTN network convergence ring, an L3 interface is set inside the device (an IP address corresponding to an L3VPN is configured on an L3 interface), and a bridging relationship between an L2 interface and an L3 interface is established, so as to implement forwarding of traffic between the L2VPN and the L3VPN, and a device that completes a forwarding function is called an L2-L3 bridging node;

in order to realize service Protection when L2-L3 bridge Node fails (i.e. multi-point failure occurs), a Dual-hanging form as shown in fig. 1 is usually adopted, in the L2VPN Network shown in fig. 1, Pseudo Wire (PW) Dual-homing Protection or PW Automatic Protection Switching-Dual Node Interconnection (APS-D NI, Automatic Protection Switching-Dual Node Interconnection) Protection is adopted, such PW Dual-homing Protection corresponding to Dual-homing nodes PE3/PE4, PE5/PE6, and PE7/PE8 each form a Virtual Router Redundancy Protocol (VRRP) of a host and backup gateway facing a base station, and simultaneously a Virtual Private Network (Virtual Network) Fast reroute (FRR, Fast-Re-Route) Protection Instance is configured inside the L3VPN, and a Forwarding Instance (PN) of the Virtual Private Network is configured by a backup VPN Forwarding Router (PN & backup PN) Node under the primary and backup VPN, the fault detection between the PE nodes is realized by using an Operation, administration, and Maintenance (OAM) function of an LSP layer.

In the existing networking protection technology for the LTE service carried by the PTN, due to the difference of protocols and protection modes of the L2VPN and the L3VPN, the linkage switching of the L2VPN and the L3VPN protection cannot be realized, faults often occur in a transmission network as shown in figure 2, namely, the core layer optical cable and the convergence layer optical cable simultaneously fail, and the reasons of the faults may be caused by the condition that the convergence layer optical cable and the core layer optical cable have the same route or the same well, or caused by the condition that the core layer optical cable and the convergence layer simultaneously fail; when a fault as shown in fig. 2 occurs, in the L2VPN, the host bridging node PE3 cannot forward the downlink traffic of the LTE network to the LTE base station eNB-1, but cannot sense the fault occurring in the L2VPN in the L3VPN range, and the downlink traffic is still sent to the PE3, which may cause interruption of the downlink traffic;

In addition, when optical cables in different office directions of the core layer are routed in the same way or a multi-point fault occurs in the core layer, a fault as shown in fig. 3 occurs, and in the L2VPN, the traffic to the main bridge node PE3 is not switched, but a double-point fault occurs in the L3VPN (for example, a link between PE1 and PE3 and a link between PE3 and PE4 are disconnected as shown in fig. 3), so that the PE1 sends downlink traffic to PE4, but in the L2VPN network, because a link reaching PE3 still exists, uplink traffic is still sent to PE3, that is, the fault in the L3VPN cannot be sensed in the L2VPN, and the uplink traffic is interrupted.

In view of the above problem, an embodiment of the present invention describes a failure handling method for a link, as shown in fig. 5, in step 101, a link between core layer core nodes carrying a PTN is detected; wherein, the link between the core and the node is carried by at least two routing Optical cables in an Optical Transport Network (OTN); in step 102, when detecting that a link between core nodes fails, switching a routing optical cable carrying the failed link. By arranging Optical Line Protection (OLP) on the links between the core nodes, the routing Optical cable carrying the failed link can be switched when the link between the core nodes is detected to be failed.

It should be noted that the above steps can be performed by the OTN scheduling system, which is described in detail below.

The core layer takes an OTN network architecture as a core, and OTNs are arranged between core nodes (also called core offices), that is, links between the core nodes are borne on the OTNs, and power supply systems of the OTNs of the two planes can be independently arranged (the probability that the OTNs of the two planes have power supply failures at the same time is reduced); correspondingly, the service in the convergence layer may be carried by an optical fiber or an OTE, which is not limited in the embodiment of the present invention;

as shown in fig. 4, two different routing optical cables are arranged between a core node 1 and a core node 2, and two different routing optical cables are arranged between the core node 2 and a core node 3, and between the core node 1 and the core node 3, respectively, so that the link between the core nodes is carried by the two different routing optical cables;

Moreover, the links between the core nodes are provided with OLPs, for example, 10 Gigabit (GE) or 100GE channels may be used to carry the links between the core nodes, and since the links between the core nodes are already provided with OLPs, it is not necessary to additionally set sub-wavelength sub-network Connection Protection (SNCP) 1+1 to protect the links between the core nodes;

the OTN is arranged between the core nodes based on the arrangement, and the link between the core nodes is carried by at least two different routing optical cables (one routing optical cable is used as an active routing optical cable, and the other routing optical cables are used as standby routing optical cables) in the OTN, the OTN dispatching system can realize the link fault processing, when the same route or overlapping (namely, route crossing) exists in the first routing optical cable between the aggregation layer optical cable and the two core nodes, the link carried by the routing optical cable with the fault is switched to the standby routing optical cable carrying the link between the two core nodes through the OLP, so that the link can be quickly recovered from the fault;

For example, when a failure is detected in a common route or an overlapping route of a convergence layer optical cable and a routing optical cable carrying a link between two core nodes (which may also be referred to as an interoffice), and the link between the core nodes fails, the routing optical cable to which the failed route belongs is switched to a standby routing optical cable between the two core nodes, and the standby routing optical cable carries the link between the core nodes, so that the core layer and the convergence layer are ensured not to fail at the same time;

For another example, when it is detected that two links of a bearer core layer in the OTN fail simultaneously (that is, a double-point failure), that is, both the routing optical cables currently carrying the two links fail, for each failed link, the OTN scheduling system may switch the link from the routing optical cable currently failed to the standby routing optical cable, thereby implementing fast recovery of the failed link.

as an embodiment, the original protection set in the L2VPN and the L3VPN has a switching delay, so that when a link between core nodes fails, the OTN scheduling system first triggers the OLP switching process;

For example, in the fault shown in fig. 2, PW dual homing protection or PW APS-DNI protection in L2VPN is provided with a switching delay, for example, the switching delay may be set to 50 milliseconds, and when a link from PE3 to PE4 fails, the OTN scheduling system may schedule OLP switching superimposed on a routing optical cable of an OTN carrying a link from PE3 to PE4, prior to PW dual homing protection or PW APS-DNI protection in the L2VPN layer, so as to recover the link from the fault by using the above OLP switching processing;

Similarly, in the fault shown in fig. 3, the FRR protection in the L3VPN is set with a switching delay, for example, the switching delay is set to 50 milliseconds, and when the link from PE1 to PE3 (or the link from PE3 to PE 4) fails, the OTN scheduling system performs switching on the OLP superimposed on the routing optical cable on the link from PE1 to PE3 (or the link from PE3 to PE 4) prior to the FRR protection switching scheduling in the L3VPN layer, so as to recover the link from the fault.

as an embodiment, for each core node, links in two directions of the core node (an active link corresponding to a first direction and a standby link corresponding to a second direction) may be correspondingly carried by OTNs in different planes, so that, when an OTN in one plane fails, an OTN scheduling system may schedule a standby link carried by an OTN in another plane to transmit a service;

taking fig. 1 as an example, the core nodes correspond to PE1 to PE8, and for the core node PE1, links in two directions of PE1, that is, links from PE1 to PE3 (corresponding to the primary link) and links from PE3 to PE4 (corresponding to the backup link), are carried on OTNs in different planes; downlink traffic is transmitted from PE1 to PE3, and when an OTN1 carrying a link between PE1 and PE3 fails, since an OTN2 carrying a link between PE3 and PE4 does not fail (OTN1 and OTN2 are OTNs in different planes), the OTN scheduling system may schedule links in the directions of PE1, PE2, and PE4 to transmit downlink traffic.

taking fig. 2 as an example, in the failure shown in fig. 2, when an optical cable carrying a link from PE3 to PE4 of the core layer and an optical cable from PE3 of the core layer to the convergence layer fail, because the link between PE3 and PE4 is carried on a routing optical cable of an OTN with OLP (that is, a first routing optical cable and a routing optical cable are provided, and an OLP is provided), when the link between PE3 and PE4 fails, the link between PE3 and PE4 is automatically switched to a standby routing optical cable, and the link from PE3 to PE4 is recovered from the failure within 50 milliseconds due to OLP switching, for eNB-1, because 50 millisecond switching time delay of PW dual-home protection is set, when detecting a switching trigger alarm, the link alarm from PE3 to PE4 is recovered to a normal state, so that eNB-1 is not triggered to perform dual-PW protection VPN, that is, whether L2 service and downlink service are forwarded through PE3, since the link from PE1 to PE3 is always normal, LTE traffic (data) in the L3VPN network is still forwarded through PE3, and the traffic of L3VPN and L2VPN is still normal communication of traffic through the original host bridge point PE 3.

taking fig. 3 as an example, as shown in fig. 3, when a failure occurs in a link from core layer PE3 to PE4 and a link from core layer PE1 to PE3 at the same time, that is, a routing optical cable from optical carrier core layer PE3 to PE4 and a routing optical cable from carrier core layer PE1 to PE3, the link between PE3 and PE4 and the link from PE1 to PE3 are both carried on a routing optical cable of an OTN with OLP protection, that is, at least two different routing optical cables are respectively arranged between PE1 and PE3 and between PE3 and PE4, so that when a current routing optical cable carrying the link fails, the link can be dynamically switched to a standby routing optical cable; the link from PE1 to PE3 and the link from PE3 to PE4 recover to a normal link within 50 milliseconds due to OLP switching, for PE1, since 50 millisecond switching delay of FRR protection is set, when detecting a switching trigger alarm, the link alarm from PE1 to PE3 has recovered to a normal state, so that FRR protection switching for PE1 is not triggered, and uplink and downlink data in the L3VPN network are still forwarded through PE 3; in the L2VPN, the traffic to the main bridge node PE3 is not switched, and the traffic in the L2VPN is still forwarded through PE3, that is, the traffic in the L3VPN and the L2VPN still performs normal traffic communication according to the original main bridge point PE 3.

corresponding to the above description, an OTN scheduling system is further described in the embodiment of the present invention, as shown in fig. 6, the system includes:

a detecting unit 10, configured to detect links between core layer core nodes carrying a PTN; at least two routing optical cables in a link OTN between core nodes are loaded;

A switching scheduling unit 20, configured to switch a routing optical cable carrying a failed link when detecting that the link between the core nodes fails.

As an embodiment, the detecting unit 10 is further configured to detect that a common route or an overlapping route of a convergence layer optical cable of the PTN and a routing optical cable carrying a link between core nodes fails;

The switching scheduling unit 20 is further configured to switch the optical cable carrying the link between the core nodes from the routing optical cable to which the failed common route or the overlapped route belongs to the standby routing optical cable carrying the link between the core nodes.

as an embodiment, the detecting unit 10 is further configured to detect that links between multiple core nodes of a core layer in an OTN fail simultaneously;

The switching scheduling unit 20 is further configured to switch the faulty link between the core nodes from the routing optical cable carrying the current faulty link to the standby routing optical cable carrying the link between the core nodes.

as an embodiment, the original protection set in the L2VPN and the L3VPN of the PTN is provided with a switching delay;

The switching scheduling unit 20 is further configured to, when the detecting unit 10 detects that a link between the core nodes fails, trigger switching the routing optical cable carrying the failed link before the original protection.

as an embodiment, links in two different directions corresponding to a core node are correspondingly carried by OTNs in two different planes, and power supplies of the OTNs are independently set;

The detecting unit 10 is further configured to detect that a link in a first direction corresponding to the core node fails;

The switching scheduling unit 20 is further configured to schedule the link transmission traffic in the second direction using the core node.

In practical applications, the detecting unit 10 and the switching scheduling unit 20 may be implemented by a Microprocessor (MCU) or a logic programmable gate array (FPGA) in an OTN.

to sum up, in the embodiment of the present invention, for the problem that service cannot be protected in a multi-point fault scenario due to different protection modes in the L2VPN and the L3VPN without a coordinated switching mechanism, a core link of the PTN system carrying the LTE service is carried on the OTN, and a second routing optical cable between core layer core nodes is established and an OLP is set (that is, two routing optical cables and an OLP are set between core layer core nodes); therefore, when the link between the core nodes fails, the OTN scheduling system can schedule the OLP switching process, that is, switch the link from the failed optical cable to the non-failed optical cable, thereby ensuring the transmission of the service;

The original protection of the L3VPN and the L2VPN is provided with switching delay, when a link between core nodes fails, an OTN dispatching system is enabled to dispatch OLP switching preferentially, the original protection switching is prevented from being triggered, and the link is ensured to be recovered from the failure;

links in two directions of the core node are carried by OTNs in different planes (a power supply system can be independently set), and when the OTN carrying the link in one direction fails, the link in the other direction can still work normally, so that normal transmission of services is ensured.

Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media that can store program codes, such as a removable Memory device, a Random Access Memory (RAM), a Read-Only Memory (ROM), a magnetic disk, and an optical disk.

Alternatively, the integrated unit of the present invention may be stored in a computer-readable storage medium if it is implemented in the form of a software functional module and sold or used as a separate product. Based on such understanding, the technical solutions of the embodiments of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the methods described in the embodiments of the present invention. And the aforementioned storage medium includes: a removable storage device, a RAM, a ROM, a magnetic or optical disk, or various other media that can store program code.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. a fault processing method is characterized in that original protection set in a two-layer virtual private network L2VPN and a three-layer virtual private network L3VPN of a packet transport network PTN is provided with switching delay; the method comprises the following steps:

detecting links between core nodes of a core layer carrying a packet transport network PTN; wherein, the link between the core nodes is carried by at least two routing optical cables in an Optical Transport Network (OTN);

when detecting that the links between a plurality of core nodes of a bearing core layer in the OTN simultaneously fail, switching the failed link between the core nodes from a routing optical cable bearing the current failed link to a standby routing optical cable bearing the links between the core nodes prior to the original protection;

The links in two different directions corresponding to the core node are correspondingly carried by OTNs in two different planes, and the power supplies of the OTNs are independently arranged; the method further comprises the following steps:

2. the method of claim 1, wherein the method further comprises:

3. An OTN dispatching system of an optical transport network is characterized in that original protections set in a two-layer virtual private network L2VPN and a three-layer virtual private network L3VPN of a packet transport network PTN are provided with switching delay; the system comprises:

a detection unit, configured to detect a link between core nodes of a core layer of a packet transport network PTN; wherein, the links between the core nodes are carried by at least two routing optical cables in an Optical Transport Network (OTN), and are further configured to detect that the links between a plurality of core nodes of a carrier core layer in the OTN have a fault at the same time;

A switching scheduling unit, configured to switch, when detecting that a link between multiple core nodes of a bearer core layer in the OTN fails simultaneously, a failed link between the core nodes from a routing optical cable carrying a current failed link to a standby routing optical cable carrying a link between the core nodes prior to the original protection, where two links in different directions corresponding to the core nodes are correspondingly carried by OTNs in two different planes, and power supplies of the OTNs are set independently;

4. The system of claim 3,

The detecting unit is further configured to detect that a common route or an overlapped route of a convergence layer optical cable of the PTN and a routing optical cable carrying a link between the core nodes fails;