CN1384618A - Optical path establishing method for automatically exchanging optical network - Google Patents

Abstract

The invention relates to a method for establishing an optical channel in an automatic switching optical network, belonging to the technical field of optical communication. In this method, client device node 1 sends out a request for establishing an optical channel, and the optical cross-connection device node calculates the route according to the request, and forwards the request to the next client device node 2, and at the same time, the local network management system checks the status of optical resources, and the client device After receiving the request for establishing an optical channel, node 2 sends an establishment response, and transmits this information to client device node 1. When the client device node 1 receives the resource allocation confirmation message, the optical channel is established successfully. The method of the present invention can quickly establish an optical channel when network resources are tight, so the method of the present invention is completely applicable to the establishment of an optical channel in the next generation automatic switching optical network.

Description

Optical channel establishment method in automatic switching optical network

technical field

The invention relates to a method for establishing an optical channel in an automatic switching optical network, belonging to the technical field of optical communication.

Background technique

Compared with the traditional optical network, the automatically switched optical network (hereinafter referred to as ASON) has the advantages that it can flexibly and dynamically allocate optical bandwidth resources according to business needs; it can realize rapid network restoration and protection; it has stronger operability . It represents the direction of optical network development.

In the public proposal of the International Telecommunication Union, a framework definition is given to the automatic establishment of an optical path, and a basic process is given. The Optical Internet Forum once proposed corresponding methods for the establishment of optical channels, mainly using CR-LDP or RSVP-TE protocols to realize dynamic management of optical channels. The establishment of an optical channel includes the following processes:

1. The customer equipment node 1 sends a request to the customer equipment node 2 to establish an optical channel to the optical cross-connect equipment node 1 connected thereto.

2. The optical cross-connect device node 1 calculates a route according to the request of the client device node 1, and forwards the request for establishing an optical channel to the client device node 2 in sequence according to the route. After receiving the above request, the intermediate optical cross-connection equipment node involved in the forwarding process checks its optical resource status through the local network management system, including whether the wavelength of the priority level of the above request is free or can be preempted. It can be preempted if it is used by priority users. If the resource condition can satisfy the above-mentioned request for establishing an optical channel, then request the local network management system to mark this optical resource (that is, the optical wavelength and the input/output port number of the optical cross-connect device node occupied by it) as having been reserved for the above-mentioned optical channel , cannot continue to be allocated to other optical channel establishment requests.

3. After receiving and agreeing to the request for establishing an optical channel, the client device node 2 sends an optical channel establishment response, and transmits it to the client device node 1 in the reverse order of request information transfer. After receiving the response, each intermediate optical cross-connect device node allocates resources to the optical resources marked as "reserved" in the above step 2, and establishes the connection relationship between wavelengths and ports required for optical channel establishment. After the process is successful, the response information is forwarded to the client device node 1 .

4. After client device node 1 receives the above response, the optical channel is established successfully. At the same time, the customer equipment node 1 sends confirmation information for establishing an optical channel to the intermediate optical cross-connect equipment node and the customer equipment node 2 .

By adopting the above process, an optical channel can be automatically established for the optical network. However, the transmission and processing of signaling messages and the allocation of network resources in this process are completely a serial process, that is, each node device must ensure that the local node resource allocation is successful before it can transmit information. The speed at which channels are established will decrease as the size of the network increases. This obviously cannot meet the requirement of ASON to dynamically establish optical channels.

To solve the time problem, some organizations have proposed a typical parallel method. When each intermediate node receives a request to establish an optical channel, it first transmits the message to the next node device, and then allocates resources. In this way, each node allocates resources in parallel, and the time for establishing an optical channel is greatly shortened. However, since this method does not perform resource reservation, when network resources are tight, the possibility of optical channel establishment failure increases sharply, and the rapid establishment of optical channel cannot be guaranteed.

Contents of the invention

The purpose of the invention is to overcome the shortcomings of the existing optical network to quickly establish the optical channel protocol, propose a method for establishing the optical channel in the automatic switching optical network, and overcome the long time of the serial method optical channel in the prior art on the one hand. Problems, but also to overcome the shortcomings of the parallel method, when the network resources are tight, the optical channel can be quickly established.

The optical channel establishment method in the automatic switching optical network proposed by the present invention comprises the following steps:

1. The customer equipment node 1 sends a request for establishing an optical channel with the customer equipment node 2 to the optical cross-connect equipment node connected to it.

2. The optical cross-connect device node 1 calculates a route according to the request of the client device node 1, and forwards the request for establishing an optical channel to the client device node 2 in sequence according to the route. After receiving the above request, each optical cross-connect device node involved in the forwarding process checks the optical resource status through its local network management system. If the local resource status can meet the above optical channel establishment request, it requests the local network management to transfer the optical resource Marked as reserved for the above optical channel.

3. After receiving and agreeing to the request for establishing an optical channel, the client device node 2 sends an optical channel establishment response, and transmits it to the client device node 1 in the reverse order of request message delivery.

4. After the optical cross-connect device node device 2 connected to the client device node 2 sends an optical channel establishment response, it immediately performs resource allocation operations on the optical resources marked as "reserved" in process 2, and establishes the optical channel establishment. The connection relationship between wavelength and port is required. After the process is successful, the information confirming the allocation of resources is sent to the previous node.

5. When the client device node 1 receives the resource allocation confirmation message, the optical channel is established successfully. At the same time, the customer equipment node 1 sends an optical channel establishment confirmation to the optical cross-connect equipment node and the customer equipment node 2, and data transmission can be performed.

The optical channel establishment method in the automatic switching optical network proposed by the present invention overcomes the shortcomings of the prior art, and can quickly establish an optical channel when network resources are tight, so the method of the present invention is completely applicable to the next generation automatic switching optical network The establishment of the optical channel.

Description of drawings

Fig. 1 is a comparison of the optical channel establishment time of the present invention with the optical channel establishment time of the existing serial technology and the ideal parallel technology.

Specific implementation method

In the method for establishing an optical channel in an ASON proposed by the present invention, firstly, the customer equipment node 1 sends a request for establishing an optical channel with the customer equipment node 2 to the optical cross-connect equipment node connected thereto. Optical cross-connect device node 1 calculates the route according to the request of client device node 1, and forwards the request for establishing an optical channel to client device node 2 in sequence according to this route, and each optical cross-connect device node involved in the forwarding process receives After the above request, check the optical resource status through its local network management system, including whether the priority wavelength of the above request is idle or whether it can preempt the resources being used by low priority users, if the local resource status can meet the above optical channel establishment request , then request the local network management to mark this optical resource (that is, the optical wavelength and the input/output port number of the optical cross-connect device node it occupies) as reserved for the above-mentioned optical channel, and cannot continue to be allocated to other optical channel establishment requests. After receiving and agreeing to the request for establishing an optical channel, the client device node 2 sends an optical channel establishment response, and transmits it to the client device node 1 in the reverse order of request message delivery. After the optical cross-connect device node device 2 connected to the customer device node 2 sends an optical channel establishment response, it immediately performs resource allocation operations on the optical resources marked as "reserved" in process 2, and establishes the required wavelength for optical channel establishment. connection with the port. After the process is successful, the information confirming the allocation of resources is sent to the previous node. When the client device node 1 receives the resource allocation confirmation message, the optical channel is established successfully. At the same time, the client device node 1 sends an optical channel establishment confirmation message, notifying the optical cross-connect device node through which the established optical channel passes and the client device node 2 that the optical channel has been successfully established and data transmission can be performed.

During the establishment of an optical channel, the most time-consuming resource allocation step is parallel processing. The relationship between the optical channel establishment time and the network node scale is shown in Figure 1. It can be seen from Figure 1 that for the existing serial technology, the optical channel establishment time is about 200 ms when the number of optical cross-connect device nodes is 5; the optical channel establishment time is about 1100 ms when the number of optical cross-connect device nodes is 50. For a typical parallel method, when the number of optical cross-connect device nodes is 5, the optical channel establishment time is about 75ms; when the optical cross-connect device node number is 50, the optical channel establishment time is about 350ms; When the number of nodes is 5, the optical channel establishment time is about 80ms; when the number of optical cross-connect device nodes is 50, the optical channel establishment time is about 400ms. It can be seen that the time of the present invention is far lower than that of the existing serial technology, and is almost the same as that of the typical parallel method. However, because the present invention considers resource reservation, its robustness is much higher than that of typical parallel methods, especially when network resources are tight, the present invention has the characteristic of strong success in establishing optical channels.

Claims (1)

1, the optical passage establishing method in a kind of ASON is characterized in that this method may further comprise the steps:

(1) customer equipment node 1 is issued to the optical channel request of setting up of customer equipment node 2 to coupled optical cross-connection equipment node 1;

(2) optical cross-connection equipment node 1 calculates route according to the request of customer equipment node 1, and according to this route, to set up the optical channel request and be forwarded to customer equipment node 2 in proper order, during forwarding, each intermediate light Cross Connect equipment node is after receiving above-mentioned request, by the local network management system it is carried out the inspection of light resources situation, set up request, then ask the local network management system that this light resources is marked as and reserve for above-mentioned optical channel if satisfy optical channel;

(3) after customer equipment node 2 receives and agrees above-mentioned request of setting up optical channel, send optical channel and set up response, and with its retrograde sequence delivery of transmitting according to solicited message to customer equipment node 1;

(4) the optical cross-connection equipment node that links to each other with customer equipment node 2 is after sending optical channel foundation response, at once the light resources that is labeled as " reservation " state in the process above-mentioned steps 2 is carried out resource allocation, establish optical channel and set up the annexation of required wavelength and port, and will confirm that the information of Resources allocation is sent to a node;

(5) customer equipment node 1 receives the resource allocation confirmation, and then optical channel is set up successfully.

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