WO2014000181A1

WO2014000181A1 - Open shortest path first based neighbor establishing method, node, and system

Info

Publication number: WO2014000181A1
Application number: PCT/CN2012/077627
Authority: WO
Inventors: 赵敏; 杨婷
Original assignee: 华为技术有限公司
Priority date: 2012-06-27
Filing date: 2012-06-27
Publication date: 2014-01-03
Also published as: CN103004150B; CN103004150A

Abstract

The present invention is applicable in the field of communications, and provides an open shortest path first (OSPF) based neighbor establishing method. The method comprises: under the OSPF protocol, a node sending a hello packet to all interfaces of the other nodes in a region to perform neighbor synchronization; the node obtaining an interface being the first to reach a 2Way state among the interfaces, initiating link-state database (LSDB) synchronization to the interface being the first to reach the 2Way state, and suspending synchronization of a subsequent state of the remaining interfaces except the interface that the LSDB synchronization is initiated to, the subsequent state being a state following the 2Way state; after the state of the interface being the first to reach the 2Way state reaches a full state, the node sending a link-related LSA to the remaining interfaces to perform synchronization with the remaining interfaces and perform neighbor establishing, the other nodes in the region being synchronized to each other. The method provided by the present invention has the advantage of the small amount of transmitted data.

Description

Shortest path first neighbor establishment method, node and system

Technical field

The present invention belongs to the field of communications, and in particular, to a shortest path first neighbor establishment technique.

Background technique

Shortest path first (Open Shortest Path First) (OSPF) is an internal gateway protocol. It is a link-state-based routing protocol. When the OSPF interface status is available, the two interfaces (the two interfaces on the peer end) send hello packets at intervals, and then establish two. Two-way communication between two interfaces. After two-way communication is established, a series of packets are exchanged between the two interfaces to achieve database synchronization. At this point, the two interfaces form an immediate relationship. This process is generally called the OSPF neighbor establishment process.

However, OSPF is based on the interface to synchronize, that is, each interface initiates the process of establishing a neighbor to the peer interface, even if there are multiple parallel links between two network elements; for example, in two network elements (for the purpose of description) Conveniently, there are two parallel links in the network element 1 and the network element 2, respectively, which are link 1 and link 2, and the interface corresponding to link 1 is interface 1 and interface 2, and link 2 corresponds. The interface is interface 3 and interface 4. At this time, after the network element 1 or the network element 2 is reset, the network element 1 requests a link state advertisement (Link-State) to the interface 2 of the network element 2 through the interface 1. Advertisement After LSA, if interface L does not receive LSA, interface 3 and interface 4 have started LSA synchronization, so that the LSA is synchronized again between interface 3 and interface 4. This causes the same LSA to be sent multiple times, which is a lot of neighbors, the link state database (Link-State) Database, LSDB) Under a large network, all neighbors must reach the FULL state (the state where the two neighboring NEs are completely in close proximity). A large number of packets need to be transmitted, and the amount of data transmission is large.

technical problem

The purpose of the embodiments of the present invention is to provide a method for establishing a shortest path first neighbor, which aims to solve the problem that the prior art solution has a large number of transmission messages and a large amount of data transmission.

Technical solution

In one aspect, the embodiment of the present invention provides an OSPF neighbor establishment method, where the method includes:

In the shortest path first OSPF protocol, the node sends hello packets to all interfaces of other nodes in the area that are connected to the local node to perform neighbor synchronization, and synchronization is completed between other nodes in the area.

The node obtains the interface that first reaches the 2Way state of all the interfaces, initiates the link state database LSDB synchronization for the interface that first reaches the 2Way state, and suspends the synchronization of the subsequent states of the remaining interfaces except the initiated LSDB synchronization, the subsequent state. Is: the state after the 2Way state;

After the state of the interface that first reaches the 2Way state reaches the full state, the node sends a link-related link state announcement LSA to the remaining interfaces to implement synchronization with the remaining interfaces and implement neighbor establishment.

An embodiment of the present invention provides a node, where the node includes:

a sending unit, configured to send a hello message to the interface connected to the local node of the other node in the area to perform neighbor synchronization, and synchronization is completed between other nodes in the area;

Obtaining a suspending unit, which is used to obtain an interface that reaches the 2Way state in the interface of the other node, initiates LSDB synchronization on the interface that first reaches the 2Way state, and suspends subsequent state synchronization of the remaining interfaces except the initiated LSDB synchronization. The subsequent state is: the state after the 2Way state;

The remaining synchronization unit is configured to: after the state of the interface that first reaches the 2Way state reaches the full state, the node sends the link-related link state announcement LSA to the remaining interface to implement synchronization with the remaining interfaces and implement neighbor establishment.

An embodiment of the present invention provides an OSPF neighbor establishment system, where the system includes: a first node and other nodes;

The first node is configured to send a hello packet to all interfaces of the other nodes in the area that are connected to the first node to perform neighbor synchronization under the shortest path first OSPF protocol, and perform other node synchronization in the area. Synchronization has been completed;

The first node is further configured to obtain an interface that first reaches the 2Way state of all the interfaces, initiates a link state database LSDB synchronization for the interface that first reaches the 2Way state, and suspends the subsequent state of the remaining interfaces except the initiated LSDB synchronization. Synchronization, the subsequent state is: a state after the 2Way state;

After the state of the interface that reaches the 2Way state reaches the full state, the node to which the interface that reaches the full state belongs is used to flood the remaining LSAs to the nodes to which the remaining interfaces belong.

The first node is configured to send a link state advertisement LSA associated with the link to the remaining interface to implement synchronization with the remaining interfaces and implement neighbor establishment.

Beneficial effect

In the embodiment of the present invention, the technical solution provided by the present invention has the advantages of less transmission packets and small data transmission amount.

DRAWINGS

1 is a flowchart of an OSPF establishment method according to an embodiment of the present invention;

2 is a structural diagram of a node according to an embodiment of the present invention;

3 is a network structure diagram according to an embodiment of the present invention;

FIG. 4 is a flowchart of a method for establishing a shortest path first neighbor according to an embodiment of the present invention.

Embodiments of the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The embodiment of the present invention provides an OSPF neighbor establishment method, which is completed by a network side node. The method is implemented in OSPF. The method is as shown in FIG. 1 and includes the following steps:

S11. The node sends a hello packet to all interfaces of the other nodes in the area that are connected to the node to perform neighbor synchronization.

S12. The node that obtains the first 2Way state (a synchronous state, when the state is completed, the network elements of the interfaces at both ends can communicate with each other) initiates LSDB synchronization on the interface that first reaches the 2Way state. Suspending synchronization of subsequent states except the LSDB synchronization has been initiated, and the subsequent state is: the state after the 2Way state;

S13. After the state of the interface that first reaches the 2Way state reaches the full state, the node sends a link-related LSA to the remaining interface to implement synchronization with the remaining interfaces and implement neighbor establishment.

It should be noted that the link-related LSAs may include: LSA No. 1 and LSA No. 9; and, in addition, in the Ethernet link, the link-related LSA may further include: LSA.

It should be noted that, according to the provisions of RFC 2328, for each link in the area, the LSA number 1 needs to be refreshed once, so the LSA No. 1 needs to be carried in the neighbor establishment and flooding.

It should be noted that the synchronization is completed between other nodes in the foregoing area. In addition, the interface that first reaches the 2Way state may be multiple interfaces. When the interface that first reaches the 2Way state is multiple, Select one of the multiple interfaces that first reached the 2Way state to perform LSDB synchronization.

Optionally, the foregoing method may further include: before S13:

The node to which the interface in the full state belongs is flooded with the remaining LSAs to the node to which the remaining interfaces belong; the remaining LSAs include: LSAs other than the LSA No. 9.

Optionally, the implementation method of the foregoing S11 specifically includes:

When detecting a new link in the area, the node sends a hello packet to all interfaces of other nodes in the area to perform neighbor synchronization.

Optionally, after the step S13, the foregoing method may include: when all the links of the node are started at the same time or the node is restarted, all the interfaces receive the Hello packet sent by the neighboring node.

After the method of the present invention sends a hello message to all the nodes in the area, the LSDB is synchronized only to the state of the interface that first reaches the 2Way state, and the subsequent state synchronization of the remaining interfaces is suspended. When the interface reaches the full state (a type of synchronization) The state, when the state is completed, the synchronization has been completed, can be synchronized by sending the link-related LSA to the remaining interfaces. Since the synchronization of the remaining interfaces only needs to transmit the LSA associated with the link, other LSAs (LSAs other than the LSA No. 9, such as LSA No. 10) do not need to be transmitted (because other LSAs are required according to RFC2328 and the extended protocol). Both of them are flooded to the remaining interfaces by the interface that first reaches the full state, so it has the advantages of less transmission packets and small data transmission.

A specific embodiment of the present invention further provides a node, as shown in FIG. 2, including:

The sending unit 21 is configured to send a hello packet to the interface connected to the local node of the other nodes in the area to perform neighbor synchronization.

The obtaining and suspending unit 22 is configured to obtain an interface that reaches the 2Way state in the interface of the other node, initiates LSDB synchronization on the interface that first reaches the 2Way state, and suspends subsequent state synchronization of the remaining interfaces except the initiated LSDB synchronization. The subsequent state is: the state after the 2Way state;

The remaining synchronization unit 23 is configured to: after the state of the interface that first reaches the 2Way state reaches the full state, the node sends the link-related LSA to the remaining interface to implement synchronization with the remaining interfaces and implement neighbor establishment; The synchronization has been completed between the other nodes.

After the node sends a hello packet to all the nodes in the area, the LSDB synchronizes only the state of the interface that first reaches the 2Way state, and the subsequent state synchronization of the remaining interfaces is suspended. When the interface reaches the full state (a type of synchronization) The state, when the state is completed, the synchronization has been completed, can be synchronized by sending the link-related LSA to the remaining interfaces. Since the synchronization of the remaining interfaces only needs to transmit the LSA associated with the link, other LSAs (LSAs other than the LSA No. 9, such as LSA No. 10) do not need to be transmitted (because other LSAs are required according to RFC2328 and the extended protocol). Both of them are flooded to the remaining interfaces by the interface that first reaches the full state, so it has the advantages of less transmission packets and small data transmission.

Optionally, the interface that first reaches the 2Way state is multiple interfaces. When the interface that first reaches the 2Way state is multiple, the obtaining and suspending unit 22 is specifically configured to:

The LSDB synchronization of the remaining interfaces of the other nodes is obtained.

Optionally, the link state declaration LSA associated with the foregoing link specifically includes:

LSA No. 9 and LSA No. 1.

Optionally, the foregoing node further includes:

The detecting unit 24 is configured to detect whether there is a new link in the area. When detecting that there is continuity in the area, the control sending unit 21 sends a hello message to all interfaces of other nodes in the area to perform neighbor synchronization.

The present invention also provides an OSPF neighbor establishment system, which includes: a first node and other nodes;

The first node is configured to send a hello packet to all interfaces connected to the first node of other nodes in the area to perform neighbor synchronization under the shortest path first OSPF protocol, and the other nodes in the area have been Complete synchronization;

After the first node of the system of the present invention sends a hello message to all the nodes in the area, the LSDB is synchronized only to the state of the interface that first reaches the 2Way state, and the synchronization of other interfaces is suspended. When the interface reaches the full state (1) The state of synchronization, when the state is completed, the synchronization has been completed, and synchronization is performed by sending the link-related LSA to the remaining interfaces. Since the synchronization of the remaining interfaces only needs to transmit the LSA associated with the link, the other LSAs do not need to be transmitted (because the other LSAs are flooded to the remaining interfaces by the interface that first reaches the full state according to RFC2328 and the extended protocol. ), so it has the advantage of less transmission messages and a small amount of data transmission.

Example

The present invention provides an embodiment. This embodiment provides an OSPF neighbor establishment method. The network structure diagram implemented in this embodiment is shown in FIG. 3, where area 1 includes RTA, RTB, RTC, and RTD; and area 2 It includes RTE, RTF, RTG and RTA. In addition, LSDB synchronization has been completed between RTB, RTC and RTD. LSDB synchronization has also been completed between RTE, RTF and RTG. It is assumed that RTB, RTC and RTD each have an interface. The method provided in this embodiment is exemplified by the area 1. The method is as shown in FIG. 4, and includes:

S41. The RTA sends hello packets on all interfaces of the RTB, RTC, and RTD for synchronization.

S42. When the interface of the RTB (assuming that it is first reached) reaches the 2Way state, the RTA performs LSDB synchronization on the interface of the RTB, and suspends the synchronization operation of the subsequent states of the interface of the RTC and the RTD;

S43. After the interface of the RTB reaches the full state, the RTA sends a database description message to the RTC interface and the RTD interface (Database Description) After the packet, DD) message, the link-related LSA is then sent to synchronize with the RTC interface and the RTD interface (ie, the remaining interfaces).

The following is a principle implemented in this embodiment. Since the synchronization between the RTB, RTC, and RTD in the area 1 has been completed, the RTA has an interface (RTB interface) in the area 1 when it needs to synchronize with the node in the area 1. When the full state is reached, after the RTB and RTA are synchronized, the information of the existing RTC and RTD on the RTB is flooded to the RTA. Of course, in the actual situation, if there are other synchronization nodes, the RTB will also flood the information of the other synchronization nodes to the RTA; thus, the RTA only needs to send and chain when synchronizing with the RTC and the RTD. Road-related LSAs can reduce the number of LSAs and reduce the amount of data transferred.

It should be noted that the specific definition of the foregoing LSA can be referred to the RFC2328 protocol, RFC3620, and an extension protocol related thereto.

The method of neighbor establishment in area 2 is basically the same as that of area 1, except that the RTB, RTC, and RTD in area 1 are replaced with RTE, RTF, and RTG in area 2.

In the above unit and system embodiment, each module or unit included is only divided according to functional logic, but is not limited to the above division, as long as the corresponding function can be implemented; in addition, the specific name of each functional module is also They are only used to facilitate mutual differentiation and are not intended to limit the scope of the present invention.

Those skilled in the art can understand that all or part of the technical solutions provided by the embodiments of the present invention can be completed by using related hardware of the program instructions. For example, it can be done by computer running. The program can be stored in a readable storage medium such as a random access memory, a magnetic disk, an optical disk, or the like.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

An OSPF neighbor establishment method, the method includes:

In the shortest path first OSPF protocol, the node sends hello packets to all interfaces of other nodes in the area that are connected to the local node to perform neighbor synchronization, and synchronization is completed between other nodes in the area.

The node obtains the interface that first reaches the 2Way state of all the interfaces, initiates the link state database LSDB synchronization for the interface that first reaches the 2Way state, and suspends the synchronization of the subsequent states of the remaining interfaces except the initiated LSDB synchronization, the subsequent state. Is: the state after the 2Way state;

After the state of the interface that first reaches the 2Way state reaches the full state, the node sends a link-related link state announcement LSA to the remaining interfaces to implement synchronization with the remaining interfaces and implement neighbor establishment.
The method according to claim 1, wherein when the number of interfaces that reach the 2Way state is the first, the initiating the LSDB synchronization for the interface that first reaches the 2Way state includes:

Select one of the multiple interfaces that first reached the 2Way state to perform LSDB synchronization.
The method according to claim 1, wherein the link state advertisement LSA associated with the link specifically includes:

LSA No. 9 and LSA No. 1.
The method according to claim 1, further comprising: before the node sends the link-related link state announcement LSA to the remaining interface to implement synchronization with the remaining interfaces and implement neighbor establishment:

The node to which the interface in the full state belongs is flooded with the remaining LSAs to the node to which the remaining interfaces belong; the remaining LSAs include: LSAs other than the LSA No. 9.
The method according to claim 1, wherein the node sends a hello message to all interfaces of other nodes in the area for neighbor synchronization, including:

When detecting a new link in the area, the node sends a hello packet to all interfaces of other nodes in the area to perform neighbor synchronization.
The method according to claim 1, wherein the method further comprises: when all the links of the node are started at the same time or the node is restarted, all the interfaces receive the Hello message sent by the neighboring node.
A node, wherein the node comprises:

a sending unit, configured to send a hello message to the interface connected to the local node of the other node in the area to perform neighbor synchronization, and synchronization is completed between other nodes in the area;

Obtaining a suspending unit, which is used to obtain an interface that reaches the 2Way state in the interface of the other node, initiates LSDB synchronization on the interface that first reaches the 2Way state, and suspends subsequent state synchronization of the remaining interfaces except the initiated LSDB synchronization. The subsequent state is: the state after the 2Way state;

The remaining synchronization unit is configured to: after the state of the interface that first reaches the 2Way state reaches the full state, the node sends the link-related link state announcement LSA to the remaining interface to implement synchronization with the remaining interfaces and implement neighbor establishment.
The node according to claim 7, wherein when the number of interfaces that first reach the 2Way state is plural, the acquisition suspension unit is specifically configured to:

The interface of the other node that is the first to reach the 2Way state is obtained, and any one of the multiple interfaces is selected to initiate the LSDB synchronization, and the subsequent state synchronization of the remaining interfaces except the initiated LSDB synchronization is suspended.
The node according to claim 7, wherein the link state declaration LSA associated with the link specifically includes:

LSA No. 9 and LSA No. 1.
The node according to claim 7, wherein the node further comprises:

The detecting unit is configured to detect whether there is a new link in the area. When detecting that there is continuity in the area, the sending unit is configured to send a hello message to all interfaces of other nodes in the area to perform neighbor synchronization.
An OSPF neighbor establishment system, where the system includes: a first node and other nodes;

The first node is configured to send a hello packet to all interfaces of the other nodes in the area that are connected to the first node to perform neighbor synchronization under the shortest path first OSPF protocol, and perform other node synchronization in the area. Synchronization has been completed;

The first node is further configured to obtain an interface that first reaches the 2Way state of all the interfaces, initiates a link state database LSDB synchronization for the interface that first reaches the 2Way state, and suspends the subsequent state of the remaining interfaces except the initiated LSDB synchronization. Synchronization, the subsequent state is: a state after the 2Way state;

After the state of the interface that reaches the 2Way state reaches the full state, the node to which the interface that reaches the full state belongs is used to flood the remaining LSAs to the nodes to which the remaining interfaces belong.

The first node is configured to send a link state advertisement LSA associated with the link to the remaining interface to implement synchronization with the remaining interfaces and implement neighbor establishment.