KR20200068417A - Method for scheduling data traffic cyclic switch - Google Patents

Abstract

According to the present invention, disclosed is a method of scheduling traffic on a cyclic switch. A cyclic switch includes: a plurality of ports, each of which is operated as a starting point port, a stop port and a destination port; and a switch fabric connecting the plurality of ports with each other in accordance with a plurality of connection states repeated periodically. The traffic scheduling method for the cyclic switch includes: a step in which a scheduler provided in each of the ports stores inputted traffic in a buffer memory by classifying the traffic by destination; and a step in which the scheduler determines traffic of the input traffic stored in the buffer memory, which is going to be transmitted to another port in the current connection state of the switch fabric, by referring to a connection state table in which the connection state of the switch fabric is preset in accordance with a destination of each piece of the traffic to prevent the input order of the traffic from being changed on the destination port.

Description

Cyclic Switch and Traffic Scheduling Method in the Cyclic Switch {METHOD FOR SCHEDULING DATA TRAFFIC CYCLIC SWITCH}

The present invention relates to a traffic scheduling method for improving throughput of a cyclic switch.

The network switch is a communication device connecting communication nodes, and includes a switching fabric connecting multiple ports and multiple ports connected to the communication nodes and a central scheduler controlling the switching fabric.

As the processing capacity of the network switch increases, the processing capacity of the central scheduler and thus the complexity of the central scheduler is increasing. To solve this problem, a network switch has been developed to manage traffic without a central scheduler, and the network switch is called a cyclic switch.

Cyclic switches consist only of multiple ports and a switch fabric connecting them. That is, there is no central scheduler inside the cyclic switch. The switching fabric in the cyclic switch connects multiple ports in a predetermined manner (predetermined connection scheme).

As such, since the cyclic switch does not have a central scheduler having a function of optimizing and connecting connections between ports according to the distribution of traffic, throughput increases or decreases according to the distribution of traffic.

In addition, since the switch fabric in the cyclic switch connects a plurality of ports according to a predetermined method, the input order of traffic input to the source port in the process of forwarding traffic input to the source port to the destination port is the above. The input order of the traffics entering the destination port may not match.

As described above, in order to solve the problem that the input order does not match, it is necessary to further rearrange the input order of traffic input to the destination port. This rearrangement is a factor that increases the latency and complexity of the cyclic switch.

An object of the present invention is to provide a cyclic switch and a method for scheduling traffic in a cyclic switch that improves throughput and does not require reordering of traffic.

The traffic scheduling method in the cyclic switch of the present invention for achieving the above object is a plurality of ports, wherein each port operates at any one of a source port, a destination port, and a destination port, and the multiple ports are periodically repeated. A scheduling method of a cyclic switch including a switch fabric that connects the plurality of ports to each other according to a plurality of connection states, wherein the scheduler provided in each port classifies incoming traffic according to a destination and stores it in a buffer memory ; And a connection state table in which connection state of the switch fabric that can be transmitted according to a destination of each traffic is set in advance to prevent an order of input of traffic from being changed at the destination port, a plurality of input traffic stored in the buffer memory Among them, a step of determining traffic to be transmitted to another port in a current connection state of the switch fabric is performed.

The cyclic switch of the present invention includes a plurality of ports, wherein the plurality of ports each port operates as one of a source port, a destination port, and a destination port; And a switch fabric that connects the plurality of ports to each other according to a plurality of connection states that periodically circulate, and the scheduler provided in each port indicates that the input order of the input multiple traffics is changed at the destination port. In order to prevent, a memory storing a connection state table in which at least one connection state of the switch fabric that can be transmitted according to the destination of each traffic is preset; A buffer memory for classifying and storing a plurality of traffic currently input according to a destination; And a processor for determining traffic to be transmitted to another port in a current connection state of the switch fabric among a plurality of input traffics stored in the buffer memory according to the connection state table.

According to the present invention, by scheduling traffic based on a connection state of a preset switching fabric for each destination of traffic, improving throughput reduction, which is a weakness of a cyclic switch, and rearranging the input order of traffic input to a destination port As this is unnecessary, the latency and complexity of the cyclic switch can be reduced.

1 is a view showing the internal configuration of a typical network switch.
2 is a view showing the internal configuration of a cyclic switch to which the present invention is applied.
FIG. 3 is a rearranged view of each port shown in FIG. 2 to describe connection states provided by the cyclic switching fabric shown in FIG. 2.
FIG. 4 is a view showing connection states provided by the cyclic switching fabric shown in FIG. 3.
5 is a view for explaining a method of improving throughput using a stop port in a cyclic switch to which the present invention is applied.
6 is a diagram for explaining a traffic scheduling concept according to the present invention.
7 and 8 are flowcharts showing a method of determining a connection state in which an input order of traffic is not changed in a destination port according to an embodiment of the present invention in the form of an algorithm.
9 is a view showing the internal configuration of a cyclic switch according to an embodiment of the present invention.
10 is a view showing in detail the internal configuration of each port shown in FIG.
11 is a flowchart illustrating a traffic scheduling method in a cyclic switch according to an embodiment of the present invention.

Expressions such as “comprises” or “can include” that may be used in various embodiments of the present invention indicate the existence of a corresponding function, operation, or component disclosed, and additional one or more functions, operations, or The components and the like are not limited. In addition, in various embodiments of the present invention, terms such as “include” or “have” are intended to designate the existence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification. Or other features or numbers, steps, actions, components, parts, or combinations thereof, should not be excluded in advance.

In various embodiments of the present invention, expressions such as “or” include any and all combinations of words listed together. For example, "A or B" may include A, may include B, or may include both A and B.

When a component is said to be "connected" to or "connected" to another component, the component may be directly connected to or connected to the other component, but may not be connected to the component. It will be understood that other new components may exist between the other components. On the other hand, when it is mentioned that a component is "directly connected" or "directly connected" to another component, it will be understood that no other new component exists between the component and the other components. You should be able to.

Hereinafter, in order to help understanding of the present invention, some technical terms used throughout the specification will be described, and then an embodiment of the present invention will be described in detail.

Network switch

1 is a view showing the internal configuration of a typical network switch.

Referring to Figure 1, a typical network switch consists of a number of ports, a switching fabric 10 and a central scheduler 12.

Each port is composed of a transmission port (TX) and a reception port (RX).

The switching fabric 10 routes (routes) the traffic (data traffic, data frame, packet, data packet, traffic) received from the communication node to the destination port among the multiple ports under the control of the central scheduler 12. .

Cyclic switch

2 is a view showing the internal configuration of a cyclic switch to which the present invention is applied.

Referring to FIG. 2, the cyclic switch to which the present invention is applied includes N ports and a cyclic switching fabric 25 connected to a communication node, and each port has a transmission port (TX) and traffic for transmitting traffic. It includes a receiving port (TX) to receive.

The cyclic switch illustrated in FIG. 2 is an example configured to include four ports, ??port 1 (21) connected to new node 1, port 2 (22) connected to communication node 2, connected to communication node 3 Port 3 (23) and port 4 (24) connected to communication node 4.

The cyclic switching fabric 25 of the cyclic switch to which the present invention is applied, unlike the network switch shown in FIG. 1, ensures that all ports 21, 22, 23, and 24 are connected to each other without control of a central scheduler. Should be.

To this end, the cyclic switching fabric 25 is pre-configured to have multiple connection states, in order to connect all the ports 21, 22, 23, 24 to each other.

FIG. 3 is a rearranged view of each port shown in FIG. 2 to describe connection states provided by the cyclic switching fabric shown in FIG. 2, and FIG. 4 is a connection provided by the cyclic switching fabric shown in FIG. 3 It is a diagram showing states.

For an accurate understanding of the connection states provided by the cyclic switching fabric, as shown in FIG. 3, the reception ports RX1, RX2, RX3, RX4 of each port shown in FIG. 2 are cyclic switching fabric 25 ), and the transmission ports TX1, TX2, TX3, TX4 of each port are arranged on the right side of the cyclic switching fabric 25. According to this arrangement, the cyclic switch illustrated in FIGS. 2 and 3 may be referred to as a '4 × 4 cyclic switch'.

The cyclic switch fabric 25 of the 4×4 cyclic switch provides three connection states, as shown in FIG. 4. Although four connection states are shown in FIG. 4, since connection state 4 is the same as connection state 1, connection state 4 and connection state 1 are regarded as one connection state.

As such, in the 4x4 cyclic switch, the connection between all ports is completed by the three connection states provided by the cyclic switch fabric 25. Thus, without periodic repetition of the three connection states of the cyclic switch fabric 25, without the control of the central scheduler, connection between all ports is ensured. By generalizing this, all ports (N ports) may be connected to each other by N-1 connection states in an N×N cyclic switch. At this time, the time until the internal connection state of the cyclic switch fabric 25 is switched from the first connection state to the N-1th connection state is defined as one cycle.

As described above, since the cyclic switch does not have a central scheduler that controls the connection of ports in a manner optimized according to the traffic distribution, the throughput increases or decreases according to the input traffic distribution.

For example, assuming a situation in which uniform traffic is inputted to all ports and uniform traffic is inputted to ports serving as a destination, traffic having such a distribution is called uniform traffic. For Uniform traffic, the throughput of the cyclic switch will be 1 (or 100%).

On the other hand, it is assumed that all the traffic input to the network switch is inputted to only one port, and the destination of the input traffic is also one. In this specification, traffic having such a distribution is referred to as sparse traffic.

If all traffic is input to port 1 and the destination is port 4, the transmission port of port 1 and the reception port of port 4 are connected only in connection state 3, so traffic is transmitted and received only in one connection state among total 3 connection states. This is possible. In this case, the throughput is reduced to 1/3.

For N × N cyclic switches, it provides 1/N for sparse traffic and 1 for uniform traffic. In this way, the N × N cyclic switch decreases in inverse proportion to the increase in N. Therefore, in the case of an N×N cyclic switch, an improvement in throughput is required for sparse traffic.

By using some ports of the remaining ports other than the source port to which the traffic is input and the destination port corresponding to the destination of the traffic as a stop port, throughput can be improved for sparse traffic.

5 is a view for explaining a scheduling method for improving throughput using a stop port in a cyclic switch to which the present invention is applied.

First, it is assumed that all traffic is inputted to the port 1 (RX1), and the traffic inputted to the port 1 is input to the sparse traffic output through the port 4 (TX4) through the cyclic switch. In this case, port 1 acts as a source port and port 4 acts as a destination port. In each connection state, ①, ②, ③, ④, ⑤, ⑥ indicate the incoming traffic.

In connection state 1, port 1 (RX1) is connected to port 2 (TX2), so traffic 1 input to port 1 is input to port 2 (TX2). According to the above case, since port 2 is not the destination port (port 4), it is used as a stopover port.

When the cyclic switching fabric is switched from the connection state 1 to the connection state 2, in the connection state 2, the port 2 (RX2) is connected to the port 4 (TX4), so the traffic ① input to the port 2 is the final destination port in the connection state 2 It is delivered to port 4 (TX4) operating as.

Meanwhile, in the connection state 2, the port 1 (RX1) is connected to the port 3 (TX3), so the traffic ② is transmitted to the port 3 (TX3) in the connection state 2. According to the above case, since port 3 (TX3) is not a destination port, it is used as a stopover port.

When the cyclic switching fabric transitions from link state 2 to link state 3, port 3 (RX3) is connected to port 2 (TX2). In the above case, since the destination of the traffic ② is port 4, it is not delivered to port 2, but waits in the buffer memory of port 3 (RX3) until it is switched to the next connection state (connection state 4 = connection state 1).

When the cyclic switching fabric is switched from the connection state 3 to the connection state 4 (connection state 1), in the connection state 4 (connection state 1), since the port 3 (RX3) is connected to the port 4 (TX4), the cyclic switching fabric The traffic ② waiting in the buffer memory of the port 3 (RX3) at the time of transition to the connection state 4 (connection state 1) is transferred to the port 4 (TX4) operating as the final destination.

Similarly, traffic ③, ④, ⑤, and ⑥ are delivered to the final destination port 4 along the route set in each connection state. The process in which traffic ③, ④, ⑤, and ⑥ are delivered to port 4 operating as the destination port is replaced by the description of the process in which traffic ①, ② is delivered to port 4 operating as the destination port.

As described above, all traffic inputted to port 1 ①, ②, ③, ④, ⑤, and ⑥ are delivered to the final destination port 4 without loss, so it can be seen that the throughput is 100% under the above traffic conditions. This method is called a 2-hop method because the traffic is transmitted up to two times before reaching the destination.

The 2-hop method has 100% throughput for sparse traffic. However, since one traffic has to be transmitted up to twice, the resources required for transmission and reception are doubled.

In the situation where the sparse traffic is input to the cyclic switch, there is no problem in the process of delivering sparse traffic to the destination port because there are ports that can be used as idle ports (stop ports).

However, for uniform traffic, in which traffic is input to all ports, throughput is reduced to about 50% because twice the resources are required to transmit and receive traffic.

In addition, as illustrated in FIG. 5, there is a problem in that the input order of traffic input to the source port and the input order of traffic input to the destination port are different.

That is, as shown in FIG. 5, the input order of traffic input to port 1 acting as a source port is ①→②→③→④→⑤→⑥, but traffic input to port 4 acting as a destination port The input order (or reception order) is ①→③→②→④→⑥→⑤.

The changed input order needs to be corrected. In order to correct the changed input order, it is necessary to rearrange the input order of traffic. This reordering operation, as described above, increases the latency and complexity of the cyclic switch.

The present invention proposes a traffic scheduling method that can increase the throughput of a cyclic switch by using a stopover port, but solve a problem in which an input order of traffic input to a source port and an input order of traffic input to a destination port are different.

6 is a diagram for explaining a traffic scheduling concept according to the present invention.

Referring to FIG. 6, it is assumed that the source port is port 1 and the destination port is port 4. In addition, it is assumed that traffic input to port 1 is ① and ②. In this case, when traffic ① is input to port 1 and traffic ② is input, and port 4 receives traffic ① and then traffic ②, there is no need to rearrange the order of traffic input.

In order for port 4 to receive traffic in the order of ①→②, it is necessary to set the traffic input to port 1 to start transmission only in connection states 1 and 3. In this case, since the transmission of traffic starts only in two of the three connection states, the throughput for sparse traffic is reduced to 2/3. However, the input order of the traffic input to the destination port, port 4, maintains the input order of the traffic input to the port 1.

In summary, in the case of a 4x4 cyclic switch, port 1 is set as a source, traffic set to port 4 as a destination is preset to be transmitted only in connection states 1 and 3, port 1 as a source, and port 2 as a destination. If traffic is set to be transmitted only in connection status 1 and 2, and traffic set to port 1 as the destination and traffic set to port 3 is set to be transmitted only in connection status 2, the order of traffic input at the destination port (reception order) ) Can be fixed.

Based on this concept, in the present invention, in order to prevent an input order of traffic input to a source port from being changed at a destination port, a connection state in which an input order of traffic is not changed according to a destination port is determined in advance, and The connection status determined in the data is pre-stored in the memory in each port.

By doing so, each port can be scheduled to transmit the currently input traffic to the destination port only in a pre-stored connection state, thereby preventing the traffic input order from being changed at the destination port.

According to one aspect of the invention traffic Scheduling Policy 1

The traffic scheduling policy 1 of the present invention is to predetermine a connection state for each destination port in order to prevent the input order of traffic from being changed at the destination port. This connection state can be determined through a process of finding a waypoint port through which traffic passes until it reaches a destination port.

The waypoint port can be calculated in the following way.

Looking carefully at each connection state in FIG. 4, first, the traffic transmitted from port k in connection state 1 is delivered to port k+1, and the traffic transmitted from port k in connection state 2 is delivered to port k+2. Able to know. To generalize this, in the connection state s, the traffic transmitted on the port k is delivered to the k+s port. At this time, if the port k+s is greater than N, it is transferred to the port having the remainder divided by k+s by N. For convenience of explanation, when k+s is divided by N, the operation to find the remainder is expressed by mod(k+s, N). Here, N is the total number of ports provided in the cyclic switch.

When traffic passes through one waypoint port, traffic transmitted from port k in connection state s (sth connection state) is mod((k+s)+() through port mod(k+s, N) s+1), N). Generalizing this, if the traffic passes through n waypoint ports, the traffic sent from port k in connection state s is the waypoint port mod(k+s, N), waypoint port mod(k+2s+1, N). , Via the stopover port mod(k+3s+3, N), to the final stopover port mod(k+(n+1)s+(1+2+3+…+n), N).

Using the well-known relation (1+2+3+… +n) = n×(n+1)/2, mod(k+(n+1)s+(1+2+3+…+n), N) can be expressed as mod(k+(n+1)×(s+n/2), N). At this time, considering the periodicity of the cyclic switch, k is an integer from 1 to N, s is an integer from 1 to N-1, and n is an integer from 0 to N-1. n = 0 if there is no waypoint port.

As described above, when all n stop ports are calculated, a connection state may be determined based on the n stop ports. For example, if three waypoint ports are counted, the connection state connecting the destination port and the first waypoint port among the total connection states of the switch fabric, the connection state connecting the first waypoint port and the second waypoint port, two You can select the connection status connecting the third stop port and the third stop port, and the connection status connecting the third stop port and the destination port. At this time, it is possible to data the selected connection states in such a way that an identifiable indicator is given to the selected connection states.

When the above process is implemented in the form of an algorithm, it is as shown in FIGS. 7 and 8.

7 and 8 are flowcharts showing a method of determining a connection state in which an input order of traffic is not changed in a destination port according to an embodiment of the present invention in the form of an algorithm.

First, referring to FIG. 8, in step S810, variables (N, K, L, n, s, s_tx) are defined and initial conditions are input to the defined variables. Here, N is the total number of ports inside the cyclic switch, k is the port number of the source port, L is the port number of the destination port, and n is the number of the destination port that passes through until traffic reaches the destination port after transmission. The number, s is an identification number of the connection state of the cyclic switching fabric, and s_tx is a set of elements whose connection state can be set so that the input order of traffic does not change.

Next, in step S812, '0 (zero)' is input to the variable n. In this case, the element included in the set s_tx (the connection state that can be set so that the input order of traffic is not changed) does not exist.

Next, in step S814, all s satisfying mod(k+(n+1)×(s+n/2), N) = L are found and stored in the temporary variable s_temp.

Next, in step S816, it is determined whether there is an element (configurable connection state) belonging to s_tx among the elements stored in s_temp.

In step S818, among elements stored in s_temp, there is an element belonging to s_tx (configurable connection state), and elements that overlap with elements belonging to s_tx from elements stored in s_temp are deleted, and the process performed in step S816 is repeated.

In step S820, if there is no element belonging to s_tx (configurable connection state) among the elements stored in s_temp, it is assumed that the traffic is transmitted in the configurable connection state stored in s_tx and s_temp, and the time that the traffic receives to the destination port is calculated. do.

Referring to FIG. 8, in step S822, it is determined whether an order of traffic is changed based on a time (hereinafter, a reception time) received at the destination port.

In step S824, when the order of traffic is changed at the reception time, in the element (configurable connection state) stored in s_temp, an element that causes the order of traffic to be changed at the reception time of the destination port is found and deleted.

In step S826, the order of traffic is not changed at the reception time, and the element (configurable connection state) stored in s_temp is added to s_tx, and the number of stop ports n is increased by one.

In step S828, it is determined whether the number n of stop ports where 1 is increased is less than the total number N of ports in the cyclic switch.

If the number n of the waypoint ports where 1 is increased is less than the total number N of ports in the cyclic switch, steps S814 to S826 are repeatedly performed.

If the number n of the via ports increased by 1 is equal to or greater than the total number N of the internal ports of the cyclic switch, in step S830, the elements (configurable connection state) included in all s_tx and the port numbers of the via ports are Store in memory.

According to another feature of the invention traffic Scheduling Policy 2

In the traffic scheduling policy 2 of the present invention, all ports analyze the destination of the input (or received) traffic in the current connection state of the cyclic switch fabric, check whether the destination is it or not, and if not, the traffic When the connection state of the cyclic fabric is switched to the next connection state, it is scheduled to transmit immediately when the connection state is changed to the next connection state.

For example, in the buffer memory of itself, traffic that should be transmitted when it is operating as a way-over port (traffic passing through itself) and traffic that must be transmitted when it is operating as a source or destination port (external communication node) When traffic directly received from or traffic to be transmitted to an external communication node) is accumulated, it transmits when it operates as a destination port in preference to the traffic to be transmitted when it operates as a source port or a destination port. Schedule the traffic to be sent first.

Scheduling policy 3 according to another feature of the present invention

When there is a contention between the traffic to be transmitted when the user is operating as the waypoint port and the traffic to be transmitted when the user is acting as the source port or the destination port, when the traffic is to be used as the waypoint port according to the aforementioned traffic scheduling policy When priority is given to traffic to be transmitted, transmission of traffic to be transmitted may be significantly delayed when the user operates as a source port or a destination port.

Accordingly, another feature of the present invention is that the source port monitors in real time the amount of traffic that the destination port should transmit, and when the amount of traffic that the destination port needs to transmit exceeds a certain level, the source port is the corresponding destination in the current connection state. It does not send traffic to the port, but stops sending traffic until the current connection status of the next cycle arrives.

For example, it is assumed that port 1 transmits traffic 1 and traffic 2 in connection state 1 to port 4 operating as a destination port via port 2 operating as a destination port.

Port 1 monitors the amount of traffic stored in port 2 (the amount of traffic waiting on port 2), so that if the traffic to be sent to port 2 exceeds the reference traffic amount, port 1 is connected to traffic 1 and traffic in connection state 1 Do not send 2 to port 2.

Conversely, port 1 monitors the amount of traffic stored in port 2 (the amount of traffic waiting on port 2), so that if the traffic to be sent to port 2 is less than or equal to the reference traffic, port 1 is traffic 1 and traffic in connection state 1 Send 2 to port 2.

By doing this, the waypoint port can smoothly transmit traffic that needs to be transmitted when it operates as a source port or a destination port.

On the other hand, the traffic to be transmitted to port 2 exceeds the reference traffic amount, and traffic not transmitted from port 1 may transmit traffic to port 2 in connection state 1 of the next cycle. Alternatively, the port 1 may transmit traffic to the port 4 in the state where the port 4 operating as the destination port is directly connected rather than transmitting the traffic to the port 2 in the connection state 1 of the next cycle. In this case, the waypoint port is not utilized at all.

In order to implement the above-described scheduling policy 3 smoothly, all ports in the cyclic switch must share the amount of traffic accumulated in their buffer memory. To this end, in the present invention, each port transfers the amount of traffic accumulated in its buffer memory to another port. In addition, each port is configured to deliver the amount of traffic accumulated in the buffer memory of another port received from the other port to another port.

Hereinafter, the hardware configuration of the cyclic switch to which the scheduling policies 1, 2, and 3 of the present invention are applied will be described in detail.

9 is a view showing the internal configuration of a cyclic switch according to an embodiment of the present invention.

Referring to FIG. 9, the cyclic switch 100 according to an embodiment of the present invention includes a plurality of ports 110_1,… 110_N-1, 110_N and a cyclic switching fabric 120 connected to a communication node. .

Each port includes a reception port RX for receiving traffic and a transmission port TX for transmitting traffic. Each port acts as either a source port, a destination port, or a destination port.

Additionally, each port includes a scheduler 130. Each port is different from the cyclic switch shown in FIG. 2 in that it includes an independent scheduler 130. Each scheduler 130 schedules traffic according to the aforementioned traffic scheduler policies 1, 2, and 3. The internal configuration of the scheduler 130 will be described in detail with reference to FIG. 10.

The cyclic switching fabric 130 connects N ports to each other according to a plurality of connection states that periodically repeat.

10 is a view showing in detail the internal configuration of each port shown in FIG.

In FIG. 10, the internal configuration of the port N-1 (110_N-1) is illustrated, and the internal configuration of each of the other ports is replaced with a description of the internal configuration of the port N-1 (110_N-1).

Referring to FIG. 10, the port N-1 (110_N-1) includes a reception port (RX), a transmission port (TX), a classifier 111, a buffer memory 113, a scheduler 115, and a communication unit 117 do.

The receiving port RX receives multiple traffics from a communication node or other port (a port acting as a destination port or a transit port).

The transmission port (TX) is a communication port that transfers (inputs) a number of traffic transmitted from another port (a port acting as a destination port or a destination port) to another port (a port acting as a destination port or a port acting as a destination port) or a communication node. To send.

The classifier 111 classifies a plurality of traffic input through the reception port RX according to a destination. For example, the destination of each traffic can be known through analysis of destination information recorded in the header area of each traffic. The destination information includes a port number of the destination port and address information of a communication node connected to the destination port.

The buffer memory 113 is configured to store traffic classified for each destination by the classifier 111 and may be referred to as a virtual output queue (VOQ).

The scheduler 115 transfers the traffic stored in the buffer memory 113 to another port (a port acting as a destination port or a destination port) through the cyclic switch fabric 130 according to the traffic scheduling policies according to the features of the present invention described above. Send (deliver) to.

To this end, the scheduler 115 includes a processor 115A, a first memory 115B, and a second memory 115C.

The processor 115A may be implemented as a system on chip (SoC) or a system in package (SiP). The processor 115A, for example, may drive an operating system or an application program to perform various data processing and operations according to traffic scheduling policies according to the characteristics of the present invention. The processor 115A loads and processes instructions, data, or information received from other ports into a volatile memory and stores the result data in a nonvolatile memory.

In the first memory 115B, a connection state table including at least one connection state set in advance according to a destination of each traffic is stored so that an input order of traffic at a destination port is not changed. In this case, the first memory 115B may be a non-volatile memory.

The connection status table includes an indicator indicating at least one connection status indicating a port number of a source port, a port number of a destination port, a port number of a destination port, and a path through a destination port.

When the waypoint port includes the first to third waypoint ports, the indicator connects the first waypoint, the first waypoint port, and the second waypoint port indicating the connection state of the switch fabric connecting the source port and the first waypoint port The second indicator indicating the connection state of the switch fabric, the third indicator indicating the connection state of the switch fabric connecting the second stop port and the third stop port, and the connection status of the switch fabric connecting the third stop port and the destination port. It includes a fourth indicator.

If there is no waypoint port, the indicator includes a fifth indicator indicating the connection state of the switch fabric that directly connects the source port and the destination port.

It is important to note that regardless of the presence or absence of a stopover port, the indicator is data indicating a connection state set in advance so that traffic inputted to the source port does not change the input order at the destination port.

Traffic condition information of other ports transmitted through the communication unit 117 is stored in the second memory 115C. Hereinafter, traffic situation information is referred to as VOQ situation information. The VOQ status information may be information indicating the amount of traffic accumulated in the buffer memory of each of the other ports.

The processor 115A takes the connection status table stored in the first memory, VOQ status information of other ports stored in the second memory, and the VOQ status of the port containing it into the other port from the current connection status of the switch fabric 130. Decide which traffic to send.

For example, the processor 115A may send traffic from another port to the buffer memory 113 (traffic that should be transmitted when it is operating as a stopover port) and traffic delivered from a communication node (which itself acts as a source port). Traffic that needs to be transmitted) is stored, priority is given to traffic transmitted from a communication node, and traffic transmitted from another port is determined as traffic to be transmitted in the current connection state of the switch fabric 130.

In addition, before transmitting, the processor 115A considers its VOQ status and VOQ status information transmitted from other ports, and finally determines as traffic to be transmitted in the current connection status of the switch fabric 130.

In addition, the processor 115A stores the current VOQ status information transmitted from other ports in the second memory 115C, and updates the previous VOQ status information stored in the second memory in real time.

As described above, the scheduler determines the input traffic to be transmitted to the other port in the current connection state of the switch fabric among the input traffic stored in the buffer memory by referring to the connection state table, and the VOQ status information transmitted from the other ports Finally, the input traffic to be transmitted to another port in the current connection state of the switch fabric is finally determined, and the finally determined traffic is transmitted to the external communication node.

11 is a flowchart illustrating a traffic scheduling method in a cyclic switch according to an embodiment of the present invention. For understanding, FIGS. 9 and 10 may be referred together.

Referring to FIG. 11, in step S1110, the classifier 111 classifies traffic inputted to a port including itself according to a destination. This classification process may be performed based on destination information (port number of the destination port, address information of a communication node connected to the destination port) recorded in the header area of each traffic. Traffic classified by destination is stored in the buffer memory 113.

Subsequently, in step S1120, the scheduler 115 or the processor 115A refers to the connection state table pre-stored in the first memory 115B to determine the connection state of the switch fabric that can be transmitted at the time of transmitting the input traffic to the destination. The decision-making process is performed. The connection status table includes the port number of the source port, the port number of the destination port, the port number of the destination port and the source port, the destination port, and the source port of the destination port on the route that prevents the input order of traffic input to the source port from being changed. And an indicator indicating at least one connection status of the switching fabric connecting the destination port.

Subsequently, in step S1130, a process in which the scheduler 115 or the processor 115A determines whether the connection state determined in step S1120 and the current connection state of the switch fabric are the same. If they are not the same, step S1120 is performed again for other input traffic.

Subsequently, in step S1140, if the connection state determined in step S1120 and the current connection state of the switch fabric are the same, the scheduler 115 or the processor 115A sends another port's VOQ status (different from the other port). Considering the amount of traffic waiting to be transmitted in the buffer memory of the port, a process of determining whether to transmit the input traffic to the other port is performed.

For example, if the VOQ situation of the other port, that is, the amount of traffic waiting to be transmitted in the buffer memory of the other port exceeds the reference traffic amount, the current connection state of the next cycle is not transmitted without input traffic in the current connection state. It transmits the traffic input from or schedules to transmit the input traffic in the connection state that directly connects the port (destination of the input traffic) and the port containing itself (the scheduler 115).

As described above, even if the connection state determined in step S1120 and the current connection state of the switch fabric are the same, the traffic is not determined as traffic to be transmitted to another port corresponding to the destination in the current connection state of the switch fabric. Considering both the VOQ status of the included port (the amount of traffic waiting to be transmitted in its buffer memory) and the VOQ status of the other port (destination port or destination port) delivered from the other port, the current connection status is transmitted to another port. Decide what traffic to do.

In the above, the present invention has been mainly described with reference to examples, but this is merely an example, and is not intended to limit the present invention, and those of ordinary skill in the art to which the present invention pertains are not limited to the essential characteristics of the present invention. It will be appreciated that various modifications and applications not illustrated in the examples are possible. For example, each component specifically shown in the embodiments of the present invention can be implemented by modification. And differences related to these modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

Claims (13)

As a plurality of ports, each port includes a switch fabric that connects the plurality of ports to each other according to the plurality of ports periodically operating as one of a source port, a destination port, and a destination port, and a plurality of periodic connections. In the scheduling method of the click switch,
The scheduler provided in each port classifies the input traffic according to the destination and stores it in a buffer memory; And
The scheduler provided in each port refers to the connection state table in which the connection state of the switch fabric, which can be transmitted according to the destination of each traffic, is set in advance to prevent the input order of traffic from being changed at the destination port, and the buffer Determining traffic to be transmitted to another port in the current connection state of the switch fabric among the input traffic stored in the memory
Traffic scheduling method in a cyclic switch comprising a. The method of claim 1, further comprising generating the connection status table in advance,
The step of generating the connection status table in advance,
Determining at least one stopover port through which each traffic reaches the destination port;
Selecting the at least one connection state indicating a path directly connecting the port including the host (scheduler) and the destination port among a plurality of connection states and a path passing through the determined waypoint port; And
Memory storing the connection status table configured to include a port number of the destination port, a port number of the determined at least one destination port, and an indicator indicating the selected at least one connection status;
Traffic scheduling method in a cyclic switch comprising a. The method of claim 2, wherein the current connection state of the switch fabric is the s (where s is a natural number) th connection state, the total number of ports provided in the cyclic switch is N, and the traffic reaches the destination port. In traffic with n as the number of ports, and the kth port (where k is a natural number, the port number of the source port) as the source port,
Determining the at least one waypoint port,
When determining n stop ports,

It is a step of determining the port having the remainder divided by N as the port number as the n-th port. In claim 1, wherein the determining step,
Analyzing traffic input in a previous connection state of the switch fabric to determine whether a port including itself (scheduler) is a stopover port; And
When the port containing itself (scheduler) is a stopover port, the input traffic is transferred from the current connection state of the switch fabric to another port in preference to traffic stored in the buffer memory to transmit when it operates as a source port. Determining which traffic to send
Traffic scheduling method in a cyclic switch comprising a. In claim 1, wherein the determining step,
Analyzing the amount of traffic stored in the buffer memory before sending the traffic to another port through the switch fabric; And
The result of analyzing the amount of traffic and passing the data to all other ports
Traffic scheduling method in a cyclic switch further comprising a. In claim 1, wherein the determining step,
Monitoring a traffic amount stored in the buffer memory of the other port when the port including itself (scheduler) is a source port and the input traffic needs to be transmitted to another port operating as the stop port; And
When the amount of traffic stored in the buffer memory of the other port is greater than the reference traffic amount, the port including the (scheduler) and the destination port are directly transmitted without transmitting the input traffic through the traffic path according to the current connection state. Transmitting the input traffic to the destination port in a connected state
Traffic scheduling method in a cyclic switch comprising a. A plurality of ports, each port operating as one of a source port, a destination port, and a destination port; And
And a switch fabric connecting the plurality of ports to each other according to a plurality of connection states that periodically circulate,
The scheduler provided in each port,
A memory for storing a connection state table in which at least one connection state of the switch fabric that can be transmitted according to a destination of each traffic is preset in order to prevent an order of input of multiple traffics from being changed at the destination port;
A buffer memory for classifying and storing a plurality of traffic currently input according to a destination; And
A processor for determining traffic to be transmitted to another port in a current connection state of the switch fabric among a plurality of input traffics stored in the buffer memory according to the connection state table;
Cyclic switch comprising a. In claim 7, wherein the processor,
The port number of the port including itself, the port number of the destination port, the port number of the destination port, and the connection status table to which the indicator indicating the at least one connection status is mapped are generated in advance to store the memory Cyclic switch. In claim 7, wherein the processor,
The current connection state of the switch fabric is the s (where s is a natural number) th connection state, the total number of ports provided in the cyclic switch is N, and the currently input traffic passes through to reach the destination port. If the number of ports is n and the port number of the port it contains is k,
Among the plurality of ports, n stop ports are determined,

A cyclic switch that determines a port having a remainder divided by N as a port number as an nth stop port. In claim 7, wherein the processor,
By analyzing the destination information included in the traffic currently input in the previous connection state of the switch fabric, when it is determined that the port containing it is the waypoint port, the traffic to be transmitted when it operates as the source port has priority A cyclic switch that transmits the currently input traffic to the other port in the current connection state of the switch fabric to transmit the input traffic. In claim 7, wherein the processor,
A cyclic switch that analyzes the amount of traffic stored in the buffer memory before transmitting the currently input traffic to the waypoint port or the destination port through the switch fabric. In claim 11, The scheduler,
According to the control of the processor, the cyclic switch further comprises a cyclic switch that further comprises a communication unit for transmitting the result data obtained by analyzing the amount of traffic stored in the buffer memory to all other ports. In claim 7, wherein the processor,
When the traffic amount of the other port is greater than the reference traffic amount, the input traffic does not transmit the input traffic from the current connection state of the switch fabric to the other port. A cyclic switch that transmits the input traffic to the destination port at a point in time when the connection state is directly connected.

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