CN101888339A - MPLS-TP-based looped network steering protection method - Google Patents

Abstract

The invention discloses an MPLS-TP-based looped network steering protection method, which comprises: 1) configuring the forwarding entries of an LSP; and 2) clearing of looped network faults. The method does not need support from a topology discovery protocol and can realize quick switching, which has a great significance for the improvement on the performance of MPLS-TP-based looped networks.

Description

A kind of looped network based on MPLS-TP is copied nearly guard method

Technical field

The present invention relates to data communication field, relate more specifically to a kind of looped network and copy closely (Steering) guard method based on MPLS-TP.

Background technology

MPLS (Multi-protocol Label Switching, be called for short multiprotocol label switching) be a most important technology of the current packet switching network, develop into a little to multiple spot at present by point-to-point, if so complicated technology is used for carrier class network, need in MPLS, replenish powerful OAM (operation and management) function, MPLS-TP (MPLS TransportProfile, that is: MPLS transport frame) under this background, propose just, it is the protocol suite of joint working group (JWT) exploitation of ITU-T and IETF composition, relate to OAM, survivability, multinomial technology such as webmaster and chain of command, purpose are to improve function and the interoperability characteristic that transmits net.IETF is mainly finished jointly by these working groups of MPLS, CCAMP, PWE3 and L2VPN, and ITU-T has also formulated some standards, as: G.8110.1, G.8121, G.8131, G.8132, G.8113 and G.8114 wait.

At present, in the standard formulation process of MPLS-TP, the referred important agenda at aspects such as reliability and survivabilities, wherein for the linear protection of MPLS-TP, the expert that attends a meeting does not have too big objection, reaches an agreement substantially.But for the looped network protection scheme, the existing protection scheme that proposes has a variety ofly, and more representational have: the bypass guard method of FRR, the Detour guard method of FRR and based on G.8132 guard method.Wherein, APS message is not adopted in the bypass guard method of FRR, the Detour guard method of FRR; they need be at the two ends configuration management entity (MEP) (that is: dispose a large amount of management entities) in every protection path; whether to judge protection path intact, these CCM messages have been wasted a large amount of Internet resources if will send the CCM message between the paired MEP.Therefore, everybody scheme G.8132 that is based on APS message of relatively paying close attention at present.

At IETF similar working group draft (that is: draft-weingarten-mpls-tp-ring-protection) has been arranged based on ITU-T scheme G.8132, this draft has two kinds of schemes, that is: Wrapping protected mode and Steering protection scheme.Wherein the Wrapping protection scheme is a kind of quick protection scheme, and the Steering scheme is a kind of protection scheme at a slow speed, is mainly used to optimize the protection path.This patent relates generally to copies nearly (Steering) protection scheme, therefore, below we at first introduce Steering guard method in the draft.

As shown in Figure 1a, under the situation of using the Wrapping protected mode, when the looped network fault-free, LISP1 is that its operating path and work tap are described as by the label switched path of A to D:

A{W1}→B{W2}→C{W3}→D；

Protection path and protection label are:

A{P1}→F{P2}→E{P3}→D

What specify is: 1) using of label exchange: be example with Node B, when Node B when node A receives the grouping that has " label W1 ", this node is tabled look-up, the outgoing label that inquires in " label W1 " corresponding clauses and subclauses is " label W2 ", this node replaces with " label W2 " with " the label W1 " in the packets headers of receiving, will dividing into groups simultaneously, corresponding output port forwards from the clauses and subclauses that inquire;

Shown in Fig. 1 b,, C as＜B〉during link occurs fault, Node B and node C send APS (protection automatically) message along last two ports of ring to the other side respectively.After node A receives fault notification message (APS message); the topological database that node A preserves according to this locality judges which goes up ring and the following LSP that encircles is affected; for example node A judge the ring LSP 1 be affected; { W1} switches on the related protection label { P1 ' } node A with the work tap of LISP1; the data flow of LSP1 will transmit along the protection path, and the use of this protection path and label is as follows:

A{P1’}→F{P2’}→E{P3’}→D；

Such scheme is a kind of Steering based on topological database protection scheme at a slow speed, has the shortcoming of the slow and agreement complexity of the convergence rate of protection.The present invention will design a kind of novel protection scheme and address this problem.

ITU-T G.8132 with working group's draft " draft-weingarten-mpls-tp-ring-protection " of IETF in the Steering guard method mentioned exist the problem that needs complicated topological agreement to support.

Shown in Fig. 1 b; when＜B; C〉during link occurs fault; after node A receives the signalling trouble message; whether need judge the LSP 1 that encircles according to the situation of change of topological database is affected; node A could { W1} switches on the related protection label { P1 ' }, and the data flow of LSP1 will transmit along the protection path with the work tap of LISP1 then.

The main problem of this scheme is to need to introduce the Topology Discovery agreement, and introducing topology more New Deal will be brought following shortcoming.

1) at first Topology Discovery protocol convergence speed is slower, and reason is that topological protocol massages need send chain of command to handle on all at each node, can not directly handle at data surface;

2) node need know when network topology restrains;

3) increase the complexity that the Topology Discovery agreement will increase the protection agreement.

By the analysis to the problems referred to above, traditional Steering guard method needs the support of Topology Discovery agreement, exists the slow and agreement of protection speed than complicated problems.

Summary of the invention

Technical problem: the present invention seeks to provides a kind of looped network based on MPLS-TP to copy nearly guard method at the defective that background technology exists.

Technical scheme: the present invention adopts following technical scheme for achieving the above object:

It is as follows that a kind of looped network based on MPLS-TP of the present invention is copied nearly guard method:

1) configuration of the forwarding entry of LSP

The configuration that node only is correlated with to the forwarding entry of the LSP correspondence encircled from this node on the ring that is: adds described forwarding entry described LSP at the node number of link point down;

2) looped network breaks down

When looped network breaks down, the node that detects link failure blocks the message forwarding capability of the adjacent ring upper port of fault, periodically sending the SF message along two ring upper port is fault notification message, will protect the path to send datagram by switching to from operating path of ring and affected label switching path LSP on the described node simultaneously;

When ring go up node receive fault notification message after, if this SF message is up-to-date protocol massages, described node sends along two ring upper port and surveys protocol massages machine DT messages; The DT message comprises Node_ID information, and wherein, Node_ID is the node number of node on the described ring;

After the last node of ring is received the DT message, read the Node_ID information in the DT message, and search relative transferring item according to Node_ID, have only the LSP that encircles from the last node of this ring just the clauses and subclauses of correspondence, Node_ID to be arranged; The described forwarding entry of node analysis on the ring; if it is inconsistent with the port that receives this DT message that the outgoing label that is using in this forwarding entry is promptly using operating path to send the data corresponding output port; this ring is gone up node being switched to from operating path of LSP of described forwarding entry correspondence is protected the path so, otherwise transmits data on the operating path of the LSP that continues in described forwarding entry correspondence.

Beneficial effect:

The present invention is a kind of protection scheme of Steering fast; compare with traditional Steering protection scheme; this scheme does not need the support of Topology Discovery agreement, and can realize switching fast, and this is very significant to the looped network performance that promotes based on the MPLS-TP technology.

Description of drawings

Fig. 1 a is operating path under the Steering protection scheme situation and the configuration of protecting the path;

Fig. 1 b is that break down data flow under the situation of looped network switches to the schematic diagram in protection path;

Fig. 2 is the configuration of the forwarding entry that encircles out on node A of LISP 1;

Fig. 3 is a particular flow sheet of the invention process;

Fig. 4 a, 4b, 4c and 4d are embodiments of the invention.

Embodiment

The present invention proposes a kind of looped network based on MPLS-TP and copies nearly guard method, and its core content is 2 parts:

1) configuration of the forwarding entry of LSP

The configuration that node only is correlated with to the forwarding entry of the LSP correspondence encircled from this node on the ring that is: adds described forwarding entry described LSP at the node number of link point down.

2) looped network breaks down

When looped network breaks down; the node that detects link failure blocks the message forwarding capability of the adjacent ring upper port of fault; periodically send SF message (fault notification message) along two ring upper port, will protect the path to send datagram by switching to of ring and affected LSP (label switched path) on the described node simultaneously from operating path.

When ring go up node receive fault notification message (SF) after, if this SF message is up-to-date protocol massages, described node sends along two ring upper port and surveys protocol massages (DT message).The DT message comprises Node_ID information.Wherein, Node_ID is the node number of node on the described ring.

After the last node of ring is received the DT message; read the Node_ID information in the DT message; and search relative transferring item (annotating: have only the LSP that encircles from this node just the clauses and subclauses of correspondence, Node_ID to be arranged) according to Node_ID; the described clauses and subclauses of node analysis; if the outgoing label that is using in these clauses and subclauses (that is: using operating path to send data) corresponding output port is inconsistent with the port that receives this DT message; this node is protected the path with being switched to from operating path of LSP of described forwarding entry correspondence so, otherwise transmits data on the operating path of the LSP that continues in described forwarding entry correspondence.

Of particular note the structure of LSP forwarding entry at ring place on node specifies as follows shown in Fig. 2 a:

Fig. 2 is the forwarding entry of LSP1 on node A, and the inlet label is S1, and the exit from do label is W1, and the outlet of operating path is the e port, and protection outlet label is P1 ', and the outlet in protection path is the w port, and Node_D is the node number of the following link point of LSP1.

In order to further specify the solution of the present invention, step of the present invention is set forth as shown in Figure 3:

Fig. 3 is the present invention program's a handling process:

Step 301, all nodes on the ring are configured the forwarding entry of the LSP that encircles from this node, described forwarding entry are added described LSP at the node number of link point down that is:;

Step 302, looped network breaks down, and the adjacent node detection of faulty link is blocked the adjacent port of faulty link after fault;

Step 303, described faulty link adjacent node periodically sends signalling trouble message (SF), and will protect the path to send datagram by switching to from operating path of ring and affected LSP (label switched path) on the described node;

Step 304, node receives protocol massages, analyzes the type of protocol massages;

Step 305 judges that whether protocol massages is the SF message, if change step 306 over to, otherwise changes step 308 over to;

Step 306, described node judge whether the SF message that receives is up-to-date SF message, if change step 307 over to;

Step 307, the described node that receives the SF message sends probe messages DT along two ports on the ring, and DT comprises the Node_ID information of described node.

Step 308, the node of the described DT of receiving message reads the Node_ID in the message, inquires with described Node_ID and transmits middle corresponding clauses and subclauses, and analyze described forwarding entry.

Step 309 judges whether the outgoing label corresponding output port of using is consistent with the port that receives this message, if the consistent step 310 that changes over to, otherwise would change step 311 over to.

Step 310 is not switched to the data on the operating path protection path;

Step 311 is switched to the data on the operating path on the protection path;

The situation that embodiment, looped network break down:

Shown in Fig. 4 a, the node that looped network comprises has A, B, C, D, E, F and G, and the link that comprises has＜G, A 〉,＜A, B 〉,＜B, C 〉,＜C, D 〉,＜D, E〉and＜E, F〉link.LISP1 is by the label switched path of node A to node D, and at this moment, it is the e port at the outbound port of node A, and its operating path and work tap are described as:

A{WI}→B{W2}→C{W3}→D；

Protection path and protection label are:

A{P1’}→F{P2’}→E{P3’}→D；

Shown in Fig. 4 b; link＜the B of looped network; C〉fault taken place; Node B is blocked the forwarding capability of the data message of faulty link adjacent port; to protect the path to send datagram by switching to of ring and affected LSP on the B node simultaneously from operating path; and periodically sending the SF message along intact port, the processing method of node C is identical with Node B.

After the ring upper port of node is received the SF message on the ring, judge at first whether this SF message is up-to-date protocol massages, if described node periodically sends probe messages DT along the ring upper port.For example: shown in Fig. 4 c, after node D received the SF message that Node B or C send, node D sent the DT messages along two ports on the ring, and described DT message carries the node number of node D.(annotate: only identified the situation of node D transmission DT among Fig. 4 c, the ring of each among the figure is gone up node and all can be sent the DT message in fact)

After the last node of ring is received the DT message, read the Node_ID information in the DT message, and search relative transferring item, the described clauses and subclauses of node analysis according to Node_ID.Shown in Fig. 4 d, after node A received DT (D) message from its w port, node A read the node number Node_ID (D) in this message, and searched to transmit with this node number and obtain relative transferring item (annotate: may find a plurality of forwarding entrys).In Fig. 4 d; we have only listed the forwarding entry of LISP 1; node A searches the outbound port that is using in these clauses and subclauses in the forwarding entry of LISP 1 be the e port; and node A is DT (D) message of receiving from the w port; node A learns that LISP 1 has been subjected to influence; node A protects path (as figure D shown in) from operating path from switching to data flow, that is: outgoing label is replaced by P1 ', outbound port is replaced by the w port.The path of LSP 1 becomes so:

A{P1’}→F{P2’}→E{P3’}→D

From last surface analysis as can be known, the present invention can realize the LSP path is protected fast, promptly realizes protection fast in 50ms, and this scheme is compared with traditional loopback protection scheme simultaneously, and this scheme is saved superiority bandwidth in addition.

Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.

Claims (1)

1. the looped network based on MPLS-TP is copied nearly guard method, it is characterized in that described method is as follows:

1) configuration of the forwarding entry of LSP

The configuration that node only is correlated with to the forwarding entry of the LSP correspondence encircled from this node on the ring that is: adds described forwarding entry described LSP at the node number of link point down;

2) looped network breaks down

When looped network breaks down, the node that detects link failure blocks the message forwarding capability of the adjacent ring upper port of fault, periodically sending the SF message along two ring upper port is fault notification message, will protect the path to send datagram by switching to from operating path of ring and affected label switching path LSP on the described node simultaneously;

When ring go up node receive fault notification message after, if this SF message is up-to-date protocol massages, described node sends along two ring upper port and surveys protocol massages machine DT messages; The DT message comprises Node_ID information, and wherein, Node_ID is the node number of node on the described ring;

After the last node of ring is received the DT message, read the Node_ID information in the DT message, and search relative transferring item according to Node_ID, have only the LSP that encircles from the last node of this ring just the clauses and subclauses of correspondence, Node_ID to be arranged; The described forwarding entry of node analysis on the ring; if it is inconsistent with the port that receives this DT message that the outgoing label that is using in this forwarding entry is promptly using operating path to send the data corresponding output port; this ring is gone up node being switched to from operating path of LSP of described forwarding entry correspondence is protected the path so, otherwise transmits data on the operating path of the LSP that continues in described forwarding entry correspondence.

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