KR20070102318A - Protection scheme using partial double reservation for optical burst switching network - Google Patents

Abstract

A method for preventing a fault using a partial double reservation for an optical burst switching network is provided to improve a usability of network resources by quickly generating a substitute path, when a fault occurs in the optical burst switching network. A BCP(Burst Control Packet) is simultaneously transmitted to both a main path and a substitute path, and the BCP on the substitute path is reserved for an arbitrary intermediate node, rather than a destination node. When an error occurs and a fault informing message is received, resources are reserved in a reverse direction from the destination node to the substitute path. When no fault occurs on the main path, a resource release message is delivered in the reverse direction on the substitute path.

Description

Protection Scheme using Partial Double Reservation for Optical Burst Switching Network

1 is a network diagram for fault protection in an optical burst switching network

FIG. 2 is a diagram illustrating a proposed partial double reservation process when establishing a path in an optical burst switching network. FIG.

3 is a diagram for setting an alternate path using a reverse reservation proposed in case of failure in an optical burst switching network;

4 shows successful data transmission in an optical burst switching network.

The present invention relates to a fault protection scheme in an optical burst switching (OBS) network using wavelength division multiplexing, and to a fault protection scheme using a partial double reservation scheme.

OBS is proposed as an alternative to the construction of the optical Internet using only the advantages of the optical line switching method and the optical packet switching method, and an effective protection and recovery technique for this is very important for the construction of the OBS network. However, the technology of protection and recovery in the OBS network is insufficient.

Of the path-based protection schemes possible in OBS networks, the 1 + 1 protection scheme pre-configures the primary and alternate paths corresponding to the source and destination pairs so that the same burst control packet (BCP) and data bursts It is a technique of transmitting at the same time. In case of a failure on the main path, this protection scheme can be used to quickly recover the traffic caused by the failure by switching the switching to receive the BCP and data bursts that are being transferred to the alternate path. However, this method has a disadvantage in that the efficiency of resources is extremely reduced by wasting 50% of the total network resources. As such, the 1 + 1 protection scheme allows for quick recovery at the time of failure, but by reserving a lot of resources in advance, it causes a waste of resources if failure does not occur.

The present invention has been invented in view of the above-described conventional circumstances, and is effective in an optical burst switching network that not only increases the efficiency of resources through partial double reservation but also improves the reliability of the network to provide a stable service. It is an object of the invention to provide a fault protection function.

The present invention for achieving the above technical problem is a partial double reservation step of setting an alternative path for protecting the path, when a failure occurs, transmitting a data burst on the alternative path using the reverse reservation, data transmission is successful In this case, the step of releasing alternative paths increases resource utilization.

1 relates to a network configuration for fault protection in an optical burst switching network. The network consists of a main path used to transmit data bursts between the optical burst switching nodes and two end nodes, and an alternative path used in the event of a failure. The offset-time applied on the alternate path has a longer offset time than the value applied to the main path. And both end nodes must maintain information about alternate paths. This information is information to be used when establishing a partial double reservation, which is the core of the present invention, and when performing a reverse reservation when a failure occurs.

2 illustrates a process of introducing a partial double reservation when setting a path in an optical burst switching network. In the figure, paths 1-2-3-4-5 are main paths for delivering traffic during normal operation, and paths 1-6-7-8-5 are alternative paths used in case of failure. In FIG. 2, the BCP is transmitted along the main path and on the alternate path. Here, the BCP transmitted to the main path is sent toward the destination with information on the alternate route. BCPs sent on alternate paths are not delivered continuously, and the value of x determines the point at which they are sent. FIG. 2 is a case where x is 0.5, and only up to node 7, which is the middle point of the alternate path, waits until a deconfiguration packet or a failure notification message arrives from the destination. As a result, the remaining links in the alternate path can be used by other nodes, thereby increasing resource utilization.

3 shows a conceptual diagram for using an alternative path when a failure occurs in accordance with the present invention. In the figure, node 4 detects a failure when a failure occurs and transmits a failure notification message (FIS) to a destination. Since the destination node that received the failure notification message already knows the alternate route, it sends a message to reserve the resource in the reverse direction of the alternate route. If you continue with the reverse reservation and arrive at Node 7, which was already reserving a portion of the alternate route through double booking, the alternate route is fully booked. Therefore, after the preset offset-time, the source node transmits the data burst through the alternate path. The offset-time applied to the alternate path is larger than the offset-time of the main path, and thus the function of calculating the optimum offset-time is a field to be developed later, which is beyond the scope of the present invention.

FIG. 4 is a diagram for releasing and reconfiguring an alternate path when data transmission provided by the present invention is successful. Referring to FIG. 4, when the BCP on the main path successfully arrives at the destination node Node 5, the node 5 transmits an alternative path release message along the alternative path. When the alternate route release message arrives at node 7, node 7 releases the reservation of route 1-6-7, which was set during partial double reservation. Therefore, the alternate path is quickly released so that other nodes can reuse it.

As described above, the use of the " fault protection scheme using the partial double reservation scheme in the optical burst switching network " of the present invention can increase the efficiency of resources compared to the techniques of simply applying the double reservation scheme, and when no failure occurs. This has the advantage of increasing the reuse rate of resources by fast alternate path release. Therefore, the reliability of the failure can be ensured in the optical burst switching network, and the resource efficiency can be provided in ordinary times, thus greatly contributing to the effective use of the optical network.

Claims (1)

Transmit burst control packet (BCP) on the main path and alternate path at the same time when data transmission is decided, and reserve the burst control packet on the alternate path only to any intermediate node according to the value of x , if failure occurs. Reservation of resources in the reverse direction of the alternate path at the destination node receiving the failure notification message (FIS), and if the failure of the main path occurs, transmitting the resource release message in the reverse direction of the alternate path; How to protect against failure in the network.

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