KR20040023303A - Method for Controling data transmit on wavelength Division Muliplexing ring network having channel inspection function - Google Patents

Abstract

PURPOSE: A method for controlling data transmission in a WDM ring network having a channel inspection function is provided to transmit packets, in consideration of the priority order, using a MAC protocol to control the resource access of a WDM ring network so as to ensure fairness with a stable throughput. CONSTITUTION: A packet is received to a specific node(S10), a priority detector extracts a priority code value from the priority type field of the packet outputted from a receiver and transfers it to a queue control part(S12). The queue control part compares the priority of the received packet with the priority of a packet stored in a queue using the queue information stored in a queue storage part(S14). In case that the priority of the received packet is larger than the priority of the stored packet(S16), the queue control part transmits the received packet to a transmitter(S18). The transmitter extracts the information of a receiving node and judges whether the wavelength of the receiving node is usable(S20,S22). If it is judged that the wavelength of the receiving node is usable, the queue control part tunes to the wavelength of the receiving node and transmits the received packet to the receiving node(S24).

Description

Method for Controlling data transmit on wavelength Division Muliplexing ring network having channel inspection function

The present invention relates to an apparatus and method for controlling data transmission in a WDM (Wavelenth Division Multiplexing) ring network having a channel inspection function. More particularly, the present invention relates to a packet prioritization using a MAC protocol in a WDM ring network. After marking, each node can transmit data in consideration of packet priority.

WDM is emerging as a technology that can accommodate the exponentially increasing Internet traffic. WDM is a mature technology compared to OTDM (Optical Time Division Multiplexer) or OCDM (Optical Code Division Multiplexing), and it is currently gaining the most attention as a future technology because it is easy to transfer technology from equipment and expects the lowest cost when replacing equipment. .

In addition, efforts are being made to simplify the protocol stack as much as possible, and research on a ring network with excellent fault response at the WDM layer is actively underway for use in IP over WDM, which is a final destination. Therefore, the WDM ring network is likely to play a role as the core of information communication network construction in the future.

WDM ring networks, known as resilient packet rings (RPRs), use channel monitoring to drive higher throughput. This means that each node monitors the use of the wavelength before sending the packet so that packets from the ring network do not collide with each other and transmits the packet only when the wavelength is empty. Although highly efficient, there is a fairness problem in which WDM resource usage rights are concentrated in some components (eg, nodes) constituting the network.

Meanwhile, in the WDM ring network having a channel monitoring function, a MAC protocol capable of ensuring fairness and processing efficiency has been proposed.

First, the MAC protocol uses tokens, which specifies how many packets each node can send to the other nodes, and the node that receives the token can send only this maximum packet until it receives the token again. The disadvantage is that the protocol becomes too complex to ensure fairness.

Second, the MAC protocol gives a certain amount of delay before transmitting the packet to the wavelength channel, which has the advantage of guaranteeing fairness and fairness. It has the disadvantage of being reduced.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and controls resource access of the WDM ring network to ensure fairness while maintaining a throughput in the WDM ring network. It is an object of the present invention to transmit a packet in consideration of priority using a MAC protocol.

1 is a WDM ring network structure diagram.

2 is a token ring frame structure diagram used in the MAC protocol applied in the present invention.

3 is a detailed structural diagram of a protocol data unit (PDU) of FIG.

4 is a detailed block diagram of each node shown in FIG. 1;

5 is a flowchart illustrating a data transmission control method in a WDM ring network having a channel monitoring function according to an embodiment of the present invention.

In order to achieve the above object, a data transmission control method in a WDM ring network having a channel monitoring function according to a preferred embodiment of the present invention,

A method of controlling data transmission in a WDM ring network having a channel monitoring function using a MAC protocol for performing network resource access control of a data link layer using a token ring frame,

A first step of marking a priority of a corresponding packet by adding a priority field to the token ring frame;

When the packet Qn is received, a second process of comparing the priority of the packet Qn received in the queue with the packet Qn and transmitting the high priority packet to the destination node is performed. It is done.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail.

In the WDM ring network configured as shown in FIG. 1, there are various methods of transmitting data using wavelengths, but a representative method includes one tunable transmitter and one fixed wavelength for selecting a wavelength at each node. It uses a fixed receiver tuned to the channel and a function of channel inspection for channel usage.

In other words, in order to transmit a packet from a transmitting node to a receiving node of a WDM ring network, the transmitter transmits a packet by tuning the transmitter to the receiving node's inherent wavelength when not using the receiving node's inherent wavelength.

At this time, the protocol for performing network resource access control of the used data link layer is MAC, and the structure of the token ring frame applied thereto is shown in FIG.

Referring to FIG. 2, the token ring frame structure includes one byte of a start delimiter (SD) field, one byte of an access control (AC) field, one byte of a frame control (FC) field, and six bytes of a destination node address (Dest. Address) field. 6 bytes of source address field, Protocol Data Unit (PDU), 4 bytes of cyclicredundancy checking (CRC) field for error detection, 1 byte of END delimiter (ED) field, Frame Status (FS) The field consists of 1 byte.

As shown in FIG. 3, the PDU includes 8 bits of a destination service access point (DSAP) field in which transmission service access point information is stored, and 8 bits of a source service access point (SSAP) field in which reception service access point information is stored. And 8 bits of a control field consisting of a priority type field and a message type field, and a data field in which pure data is stored.

The priority type field and the message type field are composed of 4 bits, as shown in FIG. 3, and codes stored in the priority type field are shown in Table 1.

<Table 1> Configuration and function of priority type field

Code value function Priority 0000 Waiting / Default State 0 0001 Delayed <m slot One 0010 Delayed> m slot 2 0011-1111 Pending state

The m value is set to increase in proportion to the total number of nodes in the WDM ring network to which it is applied.

Meanwhile, the detailed configuration of each node shown in FIG. 1 is the same as that of FIG. 4, and each part will be described in detail below.

The receiver 2 receives a packet by tuning to a fixed wavelength.

The priority detector 2 extracts a priority code value from the priority type field of the packet output from the receiver 2.

The queue information storage unit 6 stores information on the priority type of the packets stored in the queue 10. A plurality of packets can be stored in the queue 10, and the packet information is stored in the queue information storage unit 6. The order stored in this queue 10 and the priority type of each packet are stored.

The queue control unit 8 compares the priority type of the received packet transmitted from the priority detector 4 with the priority type of the packet stored in the queue 10 and transmits the packet storage having a higher priority to the transmitter.

The transmitter 12 transmits the packet to the receiving node by tuning to a wavelength corresponding to the receiving node of the packet transmitted by the queue control unit 8.

The node configured as described above has one receiving end because the reception wavelength is fixed as shown in FIG. 1, and transmits a packet to the transmitting node by tuning to different wavelengths. It has three transmitters. The number of receivers and transmitters can be appropriately adjusted according to the number of nodes and the design method.

Hereinafter, a method of controlling data transmission in a WDM ring network having a channel monitoring function according to an embodiment of the present invention will be described in detail with reference to the flowchart shown in FIG. 5.

When the packet Qn is received at a specific node (S10), the priority detector 2 extracts a priority code value (hereinafter, priority P2) from the priority type field of the packet output from the receiver 2. The controller transmits the data to the queue controller 8 (S12).

Subsequently, the queue control unit 8 uses the queue information stored in the queue information storage unit 6 to prioritize P2 of the received packet Qn and prioritize P1 of the packet Q1 stored in the queue 10. ), And determines whether the priority P2 of the received packet Qn is greater than or equal to the priority P1 of the packet Q1 stored in the queue 10 (S16).

As a result of the determination, when the priority P2 of the received packet Qn is greater than the priority P1 of the packet Q1 stored in the queue 10 (Yes), the transmitter 12 transmits the received packet Qn. To transmit (S18).

After extracting the reception node information from the packet Qn, the transmitter 12 determines whether to use a channel (wavelength) of the reception node using a channel monitoring function (S20 and S22).

As a result of the determination, if it is determined that the channel of the receiving node is idle and available (Yes), the wavelength is tuned to the wavelength of the receiving node to transmit the packet Qn to the receiving node (S24).

On the contrary, if it is determined that the channel of the receiving node is not available because the channel of the receiving node is busy (No), the priority code value of the packet Qn is increased by 1 and stored and stored in the queue 10. When storing the packet Qn in the queue 10, it is preferable to compare the priority of the packet Qn with the priority of the prestored packet so that the packets stored in the queue 10 are stored in order of priority. (S26).

When the priority code value of the packet Qn is adjusted upward, if the priority code value is "0010", it is preferable to maintain the state without adjusting the priority code value.

On the other hand, unlike the case described above, if the priority P2 of the packet Qn received as a result of the determination in step S16 is smaller than the priority P1 of the packet Q1 stored in the queue 10 (No), The received packet Qn is stored in the queue 10 (S28), and the packet Q1 stored in the queue 10 is transmitted to the transmitter (S30).

When storing the packet Qn in the queue 10 in step S28, the received packet Qn is stored in the queue 10 according to the same procedure as described in step S26, and after S30 is performed, the transmitter 12 ) Enables data transmission according to priority by performing the operation from step S20 described above.

According to the present invention as described above, by not only forwarding packets in accordance with the priority, but also by increasing the priority of packets that have been delayed for a long time, it is possible to solve the HOL (Head of Line blocking) problem, and automatically for a specific node. It is possible to control the packet priorities so that nodes with high priority cannot take over the channel.

In addition, the present invention has the effect of improving the utilization efficiency of the WDM ring network by ensuring a high processing efficiency and fairness in the WDM ring network having a channel monitoring function through a simple MAC algorithm.

On the other hand, the present invention is not limited to the above-described embodiments, but can be modified and modified within the scope not departing from the gist of the present invention, such modifications and changes should be regarded as belonging to the following claims. will be.

Claims (4)

A method of controlling data transmission in a WDM ring network having a channel monitoring function using a MAC protocol for performing network resource access control of a data link layer using a token ring frame, A first step of marking a priority of a corresponding packet by adding a priority field to the token ring frame; When the packet Qn is received, a second process of comparing the priority of the packet Qn received in the queue with the packet Qn and transmitting the high priority packet to the destination node is performed. A data transmission control method in a WDM ring network having a channel monitoring function. The method of claim 1, In the second process The priority of the packet Qn is lower than the priority of the packet Q1 stored in the queue, so that when the packet Q1 is transmitted to the destination node, the method further includes storing the packet Qn in the queue. Method of controlling data transmission in a WDM ring network having a channel monitoring function characterized in that made. The method of claim 2, When the packet Qn is stored in a queue, a WDM having a channel monitoring function is configured to sequentially store the packets according to priorities by comparing the priorities of previously stored packets with the priorities of the packets Qn. Method of controlling data transmission in a ring network. The method of claim 1, In the first process The priority type field added to the token frame is configured in a control field configured in the token frame.