Patent Description:
One critical problem in network switches, routers and gateways may be the overload of the internal queues/first-in first-out (FIFO) memories required to buffer (or momentarily store) network frames that flow from ingress ports to egress ports.

<FIG> and <FIG> both show an example of a set of queues, which can be found in the frame dispatching stage of the Time-Sensitive Networking (TSN) standard <NUM>. TSN is a set of standard-defined mechanisms for the time-sensitive transmission of data over deterministic Ethernet networks. The IEEE <NUM> Qbv time-aware scheduler (TAS) is designed to separate the communication on the Ethernet network into fixed length, and repeating time cycles. According to <NUM>. 1Qbv, frames to be transferred can be allocated to one of two or more types of traffic classes (priorities). As shown in <FIG> or <FIG>, traffic classes may comprise traffic classes from #<NUM> to #<NUM>. Frames are transferred in cycles corresponding to the traffic class, as defined in a gate control list (GCL), to where the data is allocated. Notably, "o" shown in the GCL indicates that a transmission gate corresponding to a particular traffic class is open, and "C" shown in the GCL indicates that a transmission gate corresponding to a particular traffic class is closed.

Especially during moments of network overload and traffic burst, it is important that network nodes (e.g., switches/routers/gateways) withstand such peaks of traffic by buffering/storing the frames in internal queues to avoid unexpected frame drops due to lack of capacity, which would degrade the quality of service (QoS) of networks.

Most of existing solutions synthesized today in network nodes implement queues of a fixed depth and queue management algorithms per queue. However, given a gateway with N ingress ports and M egress ports, it can occur that, at one particular point in time, some of these ports have low activity (i.e., are quite empty) while other ports are overstressed (i.e., are nearly full). In such conditions, queues of the low activity ports may be unused while queues of other ports are collapsed. This can result in unwanted frame drops.

<CIT> Al discloses a packet transfer device including a first queue to store a first packet classified into a high priority class and a second queue to store a second packet classified into a low priority class. <CIT> Al discloses a method of performing dynamic arbitration in hardware.

In view of the above-mentioned deficiencies, embodiments of the present disclosure aim to introduce devices and methods to overcome typical instantaneous network overload conditions. In particular, an objective is to avoid frame drops, particularly, the drop of high priority packets, and thus to improve QoS in critical network scenarios. One aim is also to optimize the usage of the total amount of memory devoted to queues.

These and other objectives are achieved by embodiments as provided in the enclosed independent claims. Advantageous implementations of the embodiments are further defined in the dependent claims.

A first aspect of the disclosure provides a controller being configured to: obtain a state of each of a plurality of queues of a network node, wherein the state of a queue is indicative of a utilization of the queue, and wherein each queue is associated with a priority entry; determine, based on the states of the queues, whether the utilization of one or more queues exceeds one or more thresholds, wherein one threshold is associated with each of the plurality of queues, wherein the one or more thresholds comprises a first threshold indicative of a nearly full state of a queue; generate one or more new entries for a GCL of the network node that controls the plurality of queues, if one or more thresholds are exceeded; and provide the one or more new entries to the network node.

The controller is further configured to: determine that the utilization of one or more queues exceeds the one or more thresholds, if a quantity of frames in the queue exceeds the first threshold; and determine one or more first queues from the plurality of queues, wherein for each of the one or more first queues the quantity of frames exceeds the first threshold. The controller is further configured to determine one or more second queues from the plurality of queues, based on one or more default priority entries of the one or more second queues, wherein a default priority entry of each of the one or more second queues is lower than a respective default priority entry of one of the one or more first queues.

The GCL is responsible for a traffic shaping of frames in each queue, wherein the controller is further configured to generate the one or more new entries for the GCL, wherein a gate for each of the one or more first queues is set to open, and a gate for each of the one or more second queues is set to closed, for the one or more new entries.

Embodiments of this disclosure accordingly propose a controller for controlling GCL of queues based on the network queues status. The controller may be implemented directly in hardware (like a co-processor or peripheral of a Microcontroller or System-on-Chip (SoC) device, as a part of the network node or the like), and/or in software (as executable code running on a central processing unit (CPU) of that Microcontroller or SoC as a part of the network node or the like).

This disclosure relies on the state of each queue. In particular, when a queue reaches a defined threshold (i.e., implying that this queue is full or nearly full), such information may be sent to the controller in order to modify the GCL entries. As previously mentioned, frames are transferred in cycles corresponding to the traffic class as defined in the GCL. In particular, a gate (also named as transmission gate) corresponding to a particular traffic class is controlled to be open or closed, according to the GCL. By modifying the GCL on the fly, gates for overloaded queues (e.g., with high priority) can be set to open, and gates for less loaded or empty queues (e.g., with low priority) can be set to closed. Thus, GCL entries may be modified at runtime, depending on the traffic needs.

Notably, the one or more thresholds may be configured for instance based on specific requirements. In particular, the mechanism of the adaptive and dynamic GCL may be triggered based on a flag or an event called Queue Nearly Full Alert (QNFA). This may be implemented using the first threshold defined in this implementation. Notably, Queue Full Alert (QFA) may be not used because it is desired to not wait until the queue is full, otherwise this may lead to packets (frames) drop before the mechanism is applied. Each of the first queues may be a queue with a higher priority. If a QNFA event is detected by the high priority queue, it may request for more buffer. Accordingly, the controller would thus search for one or more queues with a lower priority. Such low priority queue may need to give its buffer to the high priority queue, When the nearly full high priority queue, e.g., queue <NUM> (priority = <NUM>), requires buffer and the controller finds a nearly empty or empty low priority queue, e.g., queue <NUM>, (priority = <NUM>), a new GCL entry will be generated for queue <NUM> and queue <NUM>. In particular, a gate for queue <NUM> is set to closed, while a gate for queue <NUM> is set to open.

In an implementation form of the first aspect, the state of the queue is indicative of a quantity of frames in the queue.

In an implementation form of the first aspect, the one or more thresholds comprises a second threshold indicative of a nearly empty state of a queue, and/or a third threshold indicative of an empty state of a queue.

The one or more thresholds may be designed to be able to trigger a Queue Nearly Empty Alert (QNEA) event, and/or a Queue empty Alert (QEA) event.

In an implementation form of the first aspect, the controller is further configured to determine the one or more second queues from the plurality of queues, based on the one or more default priority entries of the one or more second queues, a state of each of the one or more second queues, and the second threshold or the third threshold, wherein a quantity of frames in each second queue does not exceed the second threshold or the third threshold.

For instance, if the state of a queue with a lower priority shows that this queue is empty or nearly empty, this may imply that this queue may have free space in the buffer to be given up (e.g., it may be given to a nearly full high priority queue).

In an implementation form of the first aspect, the generated one or more new entries indicates the network node to open a gate for each of the one or more first queues, and to close a gate for each of the one or more second queues.

Notably, the GCL determines which traffic queue is permitted to transmit at a specific point in time within the cycle. In particular, after the new GCL entries applied, the high priority queue (e.g., queue <NUM>) is permitted to transmit its frames at a time period that was assigned to queue <NUM>, and thus avoid dropping arriving frames.

In an implementation form of the first aspect, the controller is further configured to set a timer for the generated one or more new entries, wherein the generated one or more new entries are active before the timer expires.

In particular, the generated one or more new entries of the GCL may be active for a controllable period of time.

In an implementation form of the first aspect, the controller is further configured to obtain an updated state of each of the plurality of queues from the network node.

In an implementation form of the first aspect, the controller is further configured to set each of the one or more generated GCL entries back to the default GCL entry, if it is determined that the utilization of no queue exceeds the one or more thresholds.

Notably, after the high priority queue (queue <NUM>) transmits its burst packets at the time period that was assigned to queue <NUM>, the level in queue <NUM> (i.e., the utilization of queue <NUM>) may be decreased. If the level is below the QNFA, it means no need to continue to apply this new GCL entry. Thus, the GCL configuration may be set back to the default configuration.

A second aspect of the disclosure provides a method performed by the controller of the first aspect, wherein the method comprises: obtaining a state of each of a plurality of queues of a network node, wherein the state of a queue is indicative of a utilization of the queue, and wherein each queue is associated with a priority entry; determining, based on the states of the queues, whether the utilization of one or more queues exceeds one or more thresholds, wherein one threshold is associated with each of the plurality of queues; generating one or more new entries for a GCL of the network node that controls the plurality of queues, if one or more thresholds are exceeded; and providing the one or more new entries to the network node.

The determining based on the states of the queues, whether the utilization of one or more queues exceeds one or more thresholds comprises: determining that the utilization of one or more queues exceeds the one or more thresholds, if a quantity of frames in the queue exceeds the first threshold.

Before generating one or more new entries for a gate control list of the network node that controls the plurality of queues, the method further comprises: determining one or more first queues from the plurality of queues, wherein for each of the one or more first queues the quantity of frames exceeds the first threshold, and determining one or more second queues from the plurality of queues, based on one or more default priority entries of the one or more second queues, wherein a default priority entry of each of the one or more second queues is lower than a respective default priority entry of one of the one or more first queues.

The gate control list is responsible for a traffic shaping of frames in each queue, wherein the generating one or more new entries for a gate control list of the network node that controls the plurality of queues comprises: generating the one or more new entries for the gate control list, wherein a gate for each of the one or more first queues is set to open, and a gate for each of the one or more second queues is set to closed, for the one or more new entries.

Implementation forms of the method of the third aspect may correspond to the implementation forms of the controller of the first aspect described above. The method of the third aspect and its implementation forms achieve the same advantages and effects as described above for the controller of the first aspect and its implementation forms.

A third aspect of the disclosure provides a computer program product comprising a program code for carrying out, when implemented on a processor, the method according to the second aspect and any implementation forms of the second aspect.

It has to be noted that all devices, elements, units and means described in the present application could be implemented in software or hardware elements or any kind of combination thereof.

The above described aspects and implementation forms of the present disclosure will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which:.

Illustrative embodiments of a method, device, and program product for controlling release of queues in a network node are described with reference to the figures. Although this description provides a detailed example of possible implementations, it should be noted that the details are intended to be exemplary and in no way limit the scope of the application.

Moreover, an embodiment/example may refer to other embodiments/examples. For example, any description including but not limited to terminology, element, process, explanation and/or technical advantage mentioned in one embodiment/example is applicative to the other embodiments/examples.

As previously discussed, in an existing solution that implements fixed depth queues and a queue management algorithm per queue, it may happen that queues of the inactive ports are unused (i.e., empty) while queues of other ports are collapsed (i.e., full).

<FIG> shows an example of an instantaneous status of queues in such a situation. Queue #<NUM> and queue #N both have incoming frames. At time t, frames drop is about to happen in queue #N, due to a lack of space in the queue, even though there is enough empty space in the total queue memory. This may degrade the network QoS. It can be seen that, although the implementation strategy of queue management algorithms per queue and fixed depth queues is quite simple, it is unable to self-adapt to changing traffic conditions.

In order to overcome typical instantaneous network overload conditions, this disclosure proposes to implement an adaptive and dynamic GCL based on the status of the network queues.

<FIG> shows a controller <NUM> according to an embodiment of the disclosure. The controller <NUM> may comprise processing circuitry (not shown) configured to perform, conduct or initiate the various operations of the controller <NUM> described herein. The processing circuitry may comprise hardware and software. The hardware may comprise analog circuitry or digital circuitry, or both analog and digital circuitry. The digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), digital signal processors (DSPs), or multi-purpose processors. The controller <NUM> may further comprise memory circuitry, which stores one or more instruction(s) that can be executed by the processor or by the processing circuitry, in particular under control of the software. For instance, the memory circuitry may comprise a non-transitory storage medium storing executable software code which, when executed by the processor or the processing circuitry, causes the various operations of the controller <NUM> to be performed. In one embodiment, the processing circuitry comprises one or more processors and a non-transitory memory connected to the one or more processors. The non-transitory memory may carry executable program code which, when executed by the one or more processors, causes the controller <NUM> to perform, conduct or initiate the operations or methods described herein.

In particular, the controller <NUM> is configured to obtain a state <NUM> of each of a plurality of queues of a network node <NUM>. The state <NUM> of a queue is indicative of a utilization of the queue, and wherein each queue is associated with a priority entry. The controller <NUM> is further configured to determine, based on the states <NUM> of the queues, whether the utilization of one or more queues exceeds one or more thresholds, wherein one threshold is associated with each of the plurality of queues. Then, the controller <NUM> is configured to generate one or more new entries <NUM> for a GCL of the network node <NUM> that controls the plurality of queues, if one or more thresholds are exceeded. Further, the controller <NUM> is configured to provide the one or more new entries <NUM> to the network node <NUM>.

The network device <NUM> may be a switch, a router, a gateway or the like. The plurality of queues may be implemented on an egress port of the network device <NUM>. Typically, each queue is configured with an individual transmission class, which represents an internal priority among all queues. For instance, a transmission class #N has a higher priority than a transmission class #N-<NUM>, where N being a positive integer.

The controller <NUM> may be implemented directly in hardware (like a coprocessor or peripheral of a Microcontroller or SoC device as a part of the network node <NUM>). Optionally, the controller <NUM> may be implemented in software (as executable code running on a central processing unit or CPU of that Microcontroller or SoC as a part of the network node <NUM>).

<FIG> shows an example of status of queues in the network node <NUM>, according to an embodiment of the disclosure. In particular, the GCL controller shown in <FIG> may be the controller <NUM> shown in <FIG>. Possibly, the GCL controller may be a finite state machine (FSM) or an arithmetic logic unit (ALU).

The controller <NUM> as proposed in embodiments of this disclosure relies on the state <NUM> of each queue. When a queue reaches or exceeds a defined threshold, an event may be triggered and this information is sent to the controller <NUM>, which allows the controller <NUM> to modify the entries <NUM> associated with queues, and thus to modify traffic of outgoing frames.

One or more configurable thresholds may be set for triggering different events. The one or more thresholds comprises a first threshold indicative of a nearly full state of a queue. In particular, the event triggered by the first threshold may be called QNFA. The dash line shown in <FIG> may indicate the first threshold.

Possibly, another threshold may be set to trigger a Queue Full Alert (QFA) event, i.e., for indicating that the queue is full. However, this event may not be used because it is desired to not wait until the queue is full, otherwise this may lead to frames drop before the mechanism for adapting GCL is applied.

Notably, the state <NUM> of a queue may be indicative of a quantity of frames in the queue.

According to an embodiment of this disclosure, the controller <NUM> is configured to determine that the utilization of one or more queues exceeds the one or more thresholds, if a quantity of frames in the queue exceeds the first threshold. Notably, if the quantity of frames in the queue exceeds the first threshold, the QNFA event is triggered.

Further, the controller <NUM> is configured to determine one or more first queues from the plurality of queues, wherein for each of the one or more first queues the quantity of frames exceeds the first threshold. That is, if a QNFA event is triggered in one queue, this queue will be identified by the controller <NUM>, here for example it is named as a first queue. Notably, there are be more than one queue that the quantity of frames in the queue exceeds the first threshold. Knowing that there are queues requesting more buffer (i.e., the one or more first queues, since they are nearly full), the controller <NUM> would accordingly search for one or more other queues with a lower priority. Such low priority queue may need to give its buffer to the high priority queue.

The controller <NUM> is further configured to determine one or more second queues from the plurality of queues, based on one or more default priority entries of the one or more second queues, wherein a default priority entry of each of the one or more second queues is lower than a respective default priority entry of one of the one or more first queues. Notably, a second queue should not have a priority or a transmission class higher than a first queue.

Possibly, if one or more low priority queues (i.e., the one or more second queues) are found, the controller <NUM> modifies GCL entries for the high priority queues and the low priority queues (i.e., in this implementation, the one or more first queues and the one or more second queues), in order to make frames in the high priority but overloaded queues to be transmitted first.

As previously discussed, the GCL determines which traffic queue is permitted to transmit at a specific point in time within the cycle. In particular, after the new GCL entries applied, the one or more first queues may be permitted to transmit their frames at time periods that was assigned to the one or more second queues, and thus avoid dropping arriving frames.

Preferably, the controller <NUM> would also check whether the low priority queues are capable of receiving additional frames, to avoid frames loss on the low priority queues as well.

Optionally, the one or more thresholds may further comprise a second threshold indicative of a nearly empty state of a queue, and/or a third threshold indicative of an empty state of a queue. Notably, the second threshold may be set for triggering a QNEA event, and the third threshold may be set for triggering a QEA event.

Accordingly, the controller <NUM> may be further configured to determine the one or more second queues from the plurality of queues, based on the one or more default priority entries of the one or more second queues, a state of each of the one or more second queues, and the second threshold or the third threshold, wherein a quantity of frames in each second queue does not exceed the second threshold or the third threshold.

That is, each of the second queues may be a queue with a priority lower than each of the first queues, and also the state of the second queue should meet certain conditions. In particular, the quantity of frames in each second queue does not trigger a QNFA event or a QFA event. That is, the second queue may have no frame or only a few of frames, thus it is suitable for giving up its chance for transmitting frames (for certain time period).

Accordingly, if a suitable low priority queues (i.e., the one or more second queues) are found, the controller <NUM> generates new GCL entries <NUM> for the high priority queues and the low priority queues (i.e., in this implementation, the one or more first queues and the one or more second queues), in order to make frames in the high priority but overloaded queues to be transmitted first by taking the transmit opportunity of other empty or nearly empty low priority queues.

In particular, a gate for each of the one or more first queues is set to open, while a gate for each of the one or more second queues is set to closed. Optionally, when the nearly full high priority queue, e.g., queue <NUM> (priority = <NUM>), requires buffer and the controller finds a nearly empty or empty low priority queue, e.g., queue <NUM>, (priority = <NUM>), a new GCL entry will be generated for queue <NUM> and queue <NUM>. In particular, a gate for queue <NUM> is set to closed, while a gate for queue <NUM> is set to open.

For instance, as the example shown in <FIG>, QNFA events are triggered in queue <NUM> (i.e., queue for traffic class <NUM>) and queue <NUM> (i.e., queue for traffic class <NUM>) at T05. As default GCL entry for queue <NUM> is "C", and a default GCL entry for queue <NUM> (i.e., queue for traffic class <NUM>) is "o". The controller <NUM> may thus modify the GCL entry for queue <NUM> to be "o", and the GCL entry for queue <NUM> to be "C". In this way, the overloaded queue <NUM> is able to use the transmit opportunity that was assigned to queue <NUM>, thereby avoiding the drop of high priority frames. This thus improves the QoS in critical network scenarios.

Notably, to ensure that the low priority queue that gives up its transmit opportunity also gets a chance to transmit (avoiding a possible frames drop on the low priority), a timer may be set for the new GCL entries. In particular, the new GCL entries may be active for a configurable time period (i.e., before the timer expires). As the example shown in <FIG>, the new GCL entries are only active for T06 and T07.

Further, once the outgoing frames being transmitted, the QNFA event may not be triggered anymore for the first queue. That is, the state of the first queue, i.e., the quantity of frames in the queue, may become below the first threshold.

According to an embodiment of the disclosure, the controller <NUM> may be further configured to obtain an updated state of each of the plurality of queues from the network node <NUM>. Accordingly, the controller <NUM> may be further configured to set each of the one or more generated GCL entries <NUM> back to the default GCL entry, if it is determined that the utilization of no queue exceeds the one or more thresholds.

Embodiments of this disclosure accordingly also propose a network node <NUM>. As previously described, the network device <NUM> may be a switch, a router, a gateway or the like.

<FIG> shows a network node <NUM> according to an embodiment of the disclosure. The network node <NUM> may be the network node <NUM> shown in <FIG>. The network node <NUM> may comprise processing circuitry (not shown) configured to perform, conduct or initiate the various operations of the network node <NUM> described herein. The processing circuitry may comprise hardware and software. The hardware may comprise analog circuitry or digital circuitry, or both analog and digital circuitry. The digital circuitry may comprise components such as application-specific integrated circuits (ASICs), field-programmable arrays (FPGAs), digital signal processors (DSPs), or multi-purpose processors. The network node <NUM> may further comprise memory circuitry, which stores one or more instruction(s) that can be executed by the processor or by the processing circuitry, in particular under control of the software. For instance, the memory circuitry may comprise a non-transitory storage medium storing executable software code which, when executed by the processor or the processing circuitry, causes the various operations of the network node <NUM> to be performed. In one embodiment, the processing circuitry comprises one or more processors and a non-transitory memory connected to the one or more processors. The non-transitory memory may carry executable program code which, when executed by the one or more processors, causes the network node <NUM> to perform, conduct or initiate the operations or methods described herein.

In particular, the network node <NUM> is configured to provide a state <NUM> of each of a plurality of queues to a controller <NUM>. Possibly, the controller <NUM> may be the controller <NUM> shown in <FIG>. Notably, the plurality of queues are formed at an egress port of the network node <NUM>, wherein each queue is associated with a priority entry. The network node <NUM> is further configured to obtain one or more new entries <NUM> for a GCL of the network node <NUM> that controls the plurality of queue, from the controller <NUM>.

Notably, traffic needs of the network node <NUM> are provided to the controller <NUM> at runtime. Relying on status of the plurality of queues, the controller <NUM> is able to modify on the fly the GCL entries, and thus optimize the usage of the total amount of memory of the network node <NUM>, which is devoted to queues.

According to an embodiment of the disclosure, the network device <NUM> is configured to replace one or more default entries of the GCL with the obtained one or more new entries. Accordingly, the network device <NUM> may open or close a gate for each of the plurality of queues based on the GCL. Therefore, outgoing frames of an overloaded higher priority queues may be allowed to be transmitted first. This disclosure aims at avoiding the drop of high priority frames / packets, and thus improving the QoS in critical network scenarios.

According to an embodiment of the disclosure, the network device <NUM> may be further configured to provide an updated state of each of the plurality of queues to the controller <NUM>. As previously described, after the high priority queue delivered its burst packets, the level of the high priority queue may become below the QNFA. That means, the modified GCL entries may not be needed anymore. The updated state will be provided to the controller <NUM>, and the controller <NUM> may accordingly set back the default GCL configuration for the network node <NUM>.

<FIG> show a specific example of an IEEE <NUM>. 1Qbv implementation according to an embodiment of this disclosure, each figure showing status of queues in a chronological order.

<FIG> shows eight queues of a network node <NUM>, and status of all the queues. Possibly, the network node <NUM> is a network node shown in <FIG> or <FIG>. It is assumed that a time cycle of <NUM> comprises eight time-slots, i.e., T0, T1,. , T7 as shown in <FIG>. Each time-slot is for a dedicated priority, such as T7 is allocated for the queue with a priority of <NUM>. As previously discussed, each transmission class or traffic class represents a dedicated priority. It is also assumed that a dedicated queue is set for each priority. In this example, the queue for traffic class #<NUM> has the highest priority among all eight queues.

Notably, the time cycle is repeated continuously. Order and status of each transmitting gate is defined in a GCL. In particular, at each time-slot transmission gate for each queue will be open or closed according to the GCL. According to embodiments of this disclosure, the the GCL is fixed.

<FIG> is based on <FIG>, and shows a later time point of all eight queues. Notably, four thresholds for indicating events QFA, QNFA, QNEA and QEA are further illustrated in the figure. It can be seen that a quantity of frames in the queue of traffic class #<NUM> (namely, queue <NUM>) exceeds the threshold for triggering the QNFA event. This indicates a nearly full state of that queue. According to an embodiment of the disclosure, this threshold may be the first threshold defined in the previous embodiments. This information will be provided to a controller <NUM>, particularly the controller <NUM> as shown in <FIG> or <FIG>. Therefore, the controller <NUM> knows that the queue with priority <NUM> is nearly full, i.e., it requests more buffer, otherwise further arriving frames that with high priority may be dropped.

Using the approach defined in the previous embodiments, the controller <NUM> may determine a low priority queue that accept to give from its buffer. Further, the controller <NUM> may generate new GCL entries for that low priority queue and the high priority queue, in order to indicate the network node <NUM> to transmit one or more outgoing frames of queue <NUM> first.

<FIG> is based on <FIG>. At the time point shown in <FIG>, the GCL entry of the queue for traffic class #<NUM> (i.e., queue <NUM>) at T0 has been modified from "C" as shown in <FIG> to "o". That means, a transmission gate for queue <NUM> is set to open. At the meanwhile, the GCL entry of the queue for traffic class #<NUM> (i.e., queue <NUM>) at T0 has been modified from "o" as shown in <FIG> to "C". That means, a transmission gate for queue <NUM> is set to closed.

Accordingly, the network node <NUM> open the gate for queue <NUM>. That is, the first time-slot T0 that was allocated to queue <NUM> is now allocated to queue <NUM> (i.e., a "prio <NUM>" frame is transmitted at T0).

<FIG> is further based on <FIG>. It can be seen that once the outgoing frames being transmitted, the quantity of frames in queue <NUM> no longer exceed the QNFA threshold. That is, for queue <NUM>, the QNFA event is not triggered anymore. In this way, queue <NUM> delivers its overloaded frames and thus avoids dropping arriving frames.

The updated state of queue <NUM> (no longer exceed the QNFA threshold) is provided to the controller <NUM>. Accordingly, the controller <NUM> restores the default GCL entry setting for queue <NUM> and queue <NUM>, i.e., the GCL entry of queue <NUM> at T0 is set back to "C" and the GCL entry of queue <NUM> at T0 is set back to "o". Therefore, the first time-slot T0 sends again frames from queue <NUM> (prio = <NUM>).

<FIG> shows a hardware implementation according to an embodiment of the disclosure. Notably, the different queues will send updates to GCL controller (i.e., the controller <NUM> as shown in <FIG> or <FIG>). The updates may concern the following events: QFA,.

High priority queues may be configured in the system via "qmodenTX", which represents a list of queues requesting more buffer. Low priority queues may be configured in the system via "qmodenRX", which represents a list of queues accepting to be closed. Further, in order to allow a high flexibility of implementation, a plurality of modes of the mechanism may be configured via "GCLmod".

<FIG> shows an algorithm according to an embodiment of the disclosure, based on four different modes:.

Notably, in different modes, the adaptive and dynamic GCL solution can be implemented differently. For mode "D", the adaptive and dynamic GCL is not applied.

<FIG> shows a method <NUM> according to an embodiment of the disclosure. In a particular embodiment, the method <NUM> is performed by a controller <NUM> shown in <FIG> or <FIG>. In particular, the method <NUM> comprises a step <NUM> of obtaining a state <NUM> of each of a plurality of queues of a network node <NUM>. Possibly, the network node <NUM> may be a network node <NUM> shown in <FIG> or <FIG>. In particular, the state <NUM> of a queue is indicative of a utilization of the queue, and wherein each queue is associated with a priority entry. The method further comprises a step <NUM> of determining, based on the states <NUM> of the queues, whether the utilization of one or more queues exceeds one or more thresholds, wherein one threshold is associated with each of the plurality of queues. Further, the method <NUM> comprises a step <NUM> of generating one or more new entries <NUM> for a GCL of the network node <NUM> that controls the plurality of queues, if one or more thresholds are exceeded. Then, the method <NUM> further comprises a step <NUM> of providing the one or more new entries <NUM> to the network node <NUM>.

<FIG> shows a method <NUM> according to an embodiment of the disclosure. In a particular embodiment, the method <NUM> is performed by a network device <NUM> shown in <FIG> or <FIG>. In particular, the method <NUM> comprises a step <NUM> of providing a state <NUM> of each of a plurality of queues to a controller <NUM>. Possibly, the controller <NUM> may be a controller <NUM> shown in <FIG> or <FIG>. The plurality of queues are formed at an egress port of the network node <NUM>, wherein each queue is associated with a priority entry. The method <NUM> further comprises a step <NUM> of obtaining one or more new entries <NUM> for a GCL of the network node <NUM> that controls the plurality of queues, from the controller <NUM>.

To summarize, this disclosure proposes to implement adaptive and dynamic GCL based on the network queues status. Accordingly, embodiments of the disclosure provide a controller and a network node. The innovate controller, i.e., the controller <NUM>, brings major level of flexibility to the queues, makes network nodes more robust to changes in traffic load conditions. The controller also optimizes the usage of the total amount of memory devoted to queues by modifying on the fly GCL entries. In particular, the GCL entries will be modified at runtime, depending on the traffic needs. Since outgoing frames with high priority having overloaded queues will be transmitted first, this disclosure is able to prevent the drop of high priority packets and to improve thus the QoS in critical network scenarios.

The present disclosure has been described in conjunction with various embodiments as examples as well as implementations. However, other variations can be understood and effected by those persons skilled in the art and practicing the claimed invention, from the studies of the drawings, this disclosure and the independent claims. In the claims as well as in the description the word "comprising" does not exclude other elements or steps and the indefinite article "a" or "an" does not exclude a plurality. A single element or other unit may fulfill the functions of several entities or items recited in the claims. The mere fact that certain measures are recited in the mutual different dependent claims does not indicate that a combination of these measures cannot be used in an advantageous implementation.

Moreover, it is realized by the skilled person that embodiments of the controller <NUM> and/or the network device <NUM> comprises the necessary communication capabilities in the form of e.g., functions, means, units, elements, etc., for performing the solution. Examples of other such means, units, elements and functions are: processors, memory, buffers, control logic, encoders, decoders, rate matchers, de-rate matchers, mapping units, multipliers, decision units, selecting units, switches, interleavers, de-interleavers, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiver units, transmitter units, DSPs, trellis-coded modulation (TCM) encoder, TCM decoder, power supply units, power feeders, communication interfaces, communication protocols, etc. which are suitably arranged together for performing the solution.

Claim 1:
A controller (<NUM>), configured to:
obtain a state (<NUM>) of each of a plurality of queues of a network node (<NUM>), wherein the state (<NUM>) of a queue is indicative of a utilization of the queue, and wherein each queue is associated with a priority entry;
determine, based on the states (<NUM>) of the queues, whether the utilization of one or more queues exceeds one or more thresholds, wherein one threshold is associated with each of the plurality of queues, wherein the one or more thresholds comprises a first threshold indicative of a nearly full state of a queue;
generate one or more new entries (<NUM>) for a gate control list of the network node (<NUM>) that controls the plurality of queues, if one or more thresholds are exceeded; and
provide the one or more new entries (<NUM>) to the network node (<NUM>),
wherein the controller (<NUM>) is further configured to:
determine that the utilization of one or more queues exceeds the one or more thresholds, if a quantity of frames in the queue exceeds the first threshold;
determine one or more first queues from the plurality of queues, wherein for each of the one or more first queues the quantity of frames exceeds the first threshold;
determine one or more second queues from the plurality of queues, based on one or more default priority entries of the one or more second queues, wherein a default priority entry of each of the one or more second queues is lower than a respective default priority entry of one of the one or more first queues, and
wherein the gate control list is responsible for a traffic shaping of frames in each queue, wherein the controller is further configured to:
generate the one or more new entries (<NUM>) for the gate control list, wherein a gate for each of the one or more first queues is set to open, and a gate for each of the one or more second queues is set to closed, for the one or more new entries (<NUM>).