Service rate control method and device for control plane time synchronization queue
Technical Field
The invention relates to the technical field of communication, in particular to a service rate control method and a service rate control device for a control plane time synchronization queue.
Background
SDN (Software Defined Network), which is a novel Network innovation architecture of the Emulex Network, is an implementation manner of Network virtualization, and its core technology OpenFlow separates a control plane and a data plane of a Network device, thereby implementing flexible control of Network traffic and making the Network become more intelligent as a pipeline.
The network time synchronization protocol has the problem of asymmetric round-trip ranging delay of synchronization messages, which is particularly shown in that ① the uncertainty of the time delay of switching nodes of the synchronization messages in a network, round-trip path delay of the synchronization messages is generated when the synchronization messages pass through network switching equipment such as transmission media, repeaters, switches and routers, when network load changes, the synchronization ranging messages need to be queued together with other types of messages in a cache of the network switching equipment, so that the node time delay is unstable, even conflict and packet loss can occur, which can influence the establishment of the hypothesis premise, ② the uncertainty of the round-trip propagation path of the synchronization messages in the network, when the synchronization messages pass through the network switching nodes, the round-trip path of the synchronization ranging messages is inconsistent due to the free routing, and the ranging synchronization is also inaccurate.
At present, the IEEE1588 protocol can provide the highest time synchronization precision, and for the time synchronization problem in the 61850 protocol followed by the smart grid in the future, an IEEE1588 solution is provided and introduced into the power industry to form an IEEE61588 protocol.
The improvement measures proposed for the asymmetry of the delay in the IEEE1588 protocol adopt a hardware support scheme, and a boundary clock and a transparent clock mechanism are introduced in the IEEE1588 protocol to reduce the delay jitter caused by a complex network, which all need special hardware support. The IEEE1588 protocol was originally proposed and mainly applied to clock synchronization with a measurement and control system of a local network. The IEEE1588v introduces a boundary clock to realize step-by-step synchronization with a synchronous terminal node, so that delay jitter caused by synchronous message crossing is reduced, and the boundary clock is also used for dividing a synchronous sub-domain and connecting domains with different underlying communication technologies, but the accumulation of time errors is easy to generate. The transparent clock additionally introduced in the second version IEEE1588v2 of the invention based on the v1 version is modified by measuring the residence time of the sync message (the time required for the sync message to pass through the transparent clock) and the transmission delay between the corresponding ports of the two transparent clocks, and writing the corresponding field of Follow _ Up to be transmitted to the slave clock. At present, based on IEEE1588 protocol software algorithm improvement research, asymmetric link time delay is mainly considered as interference noise, and a corresponding filtering algorithm is designed; the articles adopting the idea of fixed time delay can be realized under the support of hardware TC equipment.
How to overcome the phenomenon of delay jitter caused by asymmetric round-trip ranging delay of the synchronous message becomes a technical problem to be solved urgently.
Disclosure of Invention
Therefore, the technical problem to be solved by the present invention is that in the prior art, a phenomenon of time delay jitter occurs due to asymmetric round trip ranging delay of a sync message. Thereby providing a service rate control method and device for a control plane time synchronization queue.
In view of this, a first aspect of the embodiments of the present invention provides a method for controlling a service rate of a control plane time synchronization queue, including: establishing a time synchronization queue according to a preset identifier; acquiring a current first reservation service rate and a first actual service rate of the time synchronization queue; judging whether the first actual service rate is greater than the first reserved service rate; and if the first actual service rate is greater than the first reserved service rate, reducing the first reserved service rate.
Preferably, the method further comprises the following steps: and if the first actual service rate is less than the first reserved service rate, increasing the first reserved service rate.
Preferably, the reducing the first subscribed service rate comprises: acquiring a preset fixed delay of a head synchronous message of the time synchronization queue; calculating according to the preset fixed delay to obtain an appointed service rate adjustment amount; and reducing the first reserved service rate according to the reserved service rate adjustment amount.
Preferably, the increasing the first subscribed service rate comprises: acquiring a preset fixed delay of a head synchronous message of the time synchronization queue; calculating according to the preset fixed delay to obtain an appointed service rate adjustment amount; and increasing the first reserved service rate according to the reserved service rate adjustment amount.
Preferably, the calculating the reserved service rate adjustment amount according to the preset fixed delay time includes: acquiring the maximum service rate, the residual service rate, the preset fixed delay, the first length of each sync message before the head sync message, the second length of a dummy message inserted before each sync message before the head sync message, the third length of each service message contained in a first service queue with a priority higher than that of the time sync queue, the second actual service rate of the first service queue, the fourth length of each service message contained in a second service queue with a priority lower than that of the time sync queue, and the third actual service rate of the second service queue; calculating a target actual service rate of the time synchronization queue according to the preset fixed delay, the first length, the second length, the third length, the fourth length, the second actual service rate and the third actual service rate; and calculating the adjustment quantity of the reserved service rate according to the first reserved service rate, the maximum service rate, the residual service rate and the target actual service rate.
Preferably, the target actual service rate is calculated by using the following formula:
wherein r is
i-real' is the target actual service rate of time synchronization queue i,
is the preset fixed delay of the head synchronization packet k of the time synchronization queue i,
is the first length of the kth sync packet of the time sync queue i,
is the second length of a dummy packet inserted before the k' th sync packet,
is the third length of the kth traffic packet contained in the first traffic queue j,
is the fourth length, r, of the kth service packet contained in the second service queue h
j-realIs the first industrySaid second actual service rate, r, of service queue j
h-realIs the third actual service rate of the second traffic queue h, k is a positive integer greater than 1, k' is a positive integer greater than 0 and less than k, i is a positive integer greater than 0, j is a positive integer greater than 0 and less than M, h is a positive integer greater than 0 and less than S.
Preferably, the reserved service rate adjustment amount is calculated by using the following formula:
wherein, Δ riThe reserved service rate adjustment, r, of a time synchronization queue, iiIs the first reservation service rate, r, of the time synchronization queue, imaxIs the maximum service rate, rremainIs the residual rate, ri-real' is the target actual service rate of the time synchronization queue i, i being a positive integer greater than 0.
A second aspect of an embodiment of the present invention provides a service rate control apparatus for controlling a plane time synchronization queue, including: the establishing module is used for establishing a time synchronization queue according to a preset identifier; an obtaining module, configured to obtain a current first reservation service rate and a first actual service rate of the time synchronization queue; the judging module is used for judging whether the first actual service rate is greater than the first reserved service rate or not; a decreasing module, configured to decrease the first subscribed service rate if the first actual service rate is greater than the first subscribed service rate.
Preferably, the method further comprises the following steps: and the increasing module is used for increasing the first reserved service rate if the first actual service rate is less than the first reserved service rate.
Preferably, the reducing module comprises: a first obtaining unit, configured to obtain a preset fixed delay of a head synchronization packet of the time synchronization queue; the first calculating unit is used for calculating to obtain the adjustment quantity of the reserved service rate according to the preset fixed delay; a reducing unit configured to reduce the first subscribed service rate according to the subscribed service rate adjustment amount.
Preferably, the increasing module includes: a second obtaining unit, configured to obtain a preset fixed delay of the head synchronization packet of the time synchronization queue; the second calculating unit is used for calculating to obtain the adjustment quantity of the reserved service rate according to the preset fixed delay; and the increasing unit is used for increasing the first reserved service rate according to the reserved service rate adjustment amount.
Preferably, the calculating the reserved service rate adjustment amount according to the preset fixed delay time includes: acquiring the maximum service rate, the residual service rate, the preset fixed delay, the first length of each sync message before the head sync message, the second length of a dummy message inserted before each sync message before the head sync message, the third length of each service message contained in a first service queue with a priority higher than that of the time sync queue, the second actual service rate of the first service queue, the fourth length of each service message contained in a second service queue with a priority lower than that of the time sync queue, and the third actual service rate of the second service queue; calculating a target actual service rate of the time synchronization queue according to the preset fixed delay, the first length, the second length, the third length, the fourth length, the second actual service rate and the third actual service rate; and calculating the adjustment quantity of the reserved service rate according to the first reserved service rate, the maximum service rate, the residual service rate and the target actual service rate.
Preferably, the target actual service rate is calculated by using the following formula:
wherein r is
i-real' is the target actual service rate of time synchronization queue i,
is the preset fixed delay of the head synchronization packet k of the time synchronization queue i,
is the first length of the kth sync packet of the time sync queue i,
is the second length of a dummy packet inserted before the k' th sync packet,
is the third length of the kth traffic packet contained in the first traffic queue j,
is the fourth length, r, of the kth service packet contained in the second service queue h
j-realIs the second actual service rate, r, of the first traffic queue, j
h-realIs the third actual service rate of the second traffic queue h, k is a positive integer greater than 1, k' is a positive integer greater than 0 and less than k, i is a positive integer greater than 0, j is a positive integer greater than 0 and less than M, h is a positive integer greater than 0 and less than S.
Preferably, the reserved service rate adjustment amount is calculated by using the following formula:
wherein, Δ riThe reserved service rate adjustment, r, of a time synchronization queue, iiIs the first reservation service rate, r, of the time synchronization queue, imaxIs the maximum service rate, rremainIs the residual rate, ri-real' is the target actual service rate of the time synchronization queue i, i being a positive integer greater than 0.
The technical scheme of the invention has the following advantages:
the service rate control method and device for the control plane time synchronization queue provided by the embodiment of the invention, by constructing an independent time synchronization queue and comparing the acquired first actual service rate of the time synchronization queue with the first reserved service rate thereof in real time, when the first actual service rate is not equal to the first subscribed service rate, adjusting the first subscribed service rate in real time according to the requirement to make the first actual service rate approach to the first subscribed service rate, thereby controlling the time of the head synchronous message of the time synchronous queue entering the switching node, so that the synchronous message has a definite preset fixed time delay in the switch, further realizing the effect of preventing time delay jitter, under the condition of not occupying the effective bandwidth of the switch, the aim of consuming the waiting time of the synchronous message is achieved, and the possibility of discarding the synchronous packet at the tail part of the queue is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a flowchart of a service rate control method for a control plane time synchronization queue according to embodiment 1 of the present invention;
fig. 2 is a schematic diagram of a time synchronization queue obtaining an actual service rate according to embodiment 1 of the present invention;
fig. 3 is a schematic diagram of a process of reducing discard of a sync message tail in embodiment 1 of the present invention;
fig. 4 is another flowchart of a method for controlling service rate of a control plane time synchronization queue according to embodiment 1 of the present invention;
fig. 5 is a block diagram of a service rate control apparatus for a control plane time synchronization queue according to embodiment 2 of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Example 1
The embodiment provides a power grid reliability analysis method, which is suitable for analyzing the reliability of a power grid system, and as shown in fig. 1, the method includes the following steps:
s11: establishing a time synchronization queue according to a preset identifier; specifically, an independent virtual time synchronization queue (i.e., a time synchronization queue) with "destination as distinction (i.e., preset identification)" is constructed at the input port of the switch to distinguish traffic queues of other types from the switch, and the destination distinction prevents blocking between different sync message flows in the same switch.
S12: acquiring a current first reservation service rate and a first actual service rate of a time synchronization queue; specifically, as shown in fig. 2, when a sync message enters the sync queue, a virtual time sync queue i e [1, N ] is formed](i.e., time synchronization queue), the working method of the time synchronization queue is as follows: (a) the synchronization message entering the virtual synchronization queue makes the time synchronization queue enter a Backlog state (specifically, the head synchronization message of the time synchronization queue is in a waiting-to-send state, that is, the time synchronization queue already obtains a scheduling service resource and the head synchronization message has a message to be scheduled and forwarded), and the queue controller sends a VTQ reservation rate r in the Backlog state to the queue scheduleri(when it is specifically indicatedA first reserved service rate of the inter-synchronization queue i), wherein the first reserved service rate is equal to the length of the current header synchronization message divided by the waiting time of the synchronization message; the queue scheduler calculates VTSQ actual rate r according to fairness algorithm principlei-real(specifically, the current first actual service rate of the time synchronization queue i), specifically, r can be calculated by the following formulai-real:
Wherein r isremainIs the remaining service rate of the queue scheduler, rmaxIs the maximum service rate of the queue scheduler, and the queue scheduler then returns the VTSQ actual rate to the queue controller.
S13: and judging whether the first actual service rate is greater than the first reserved service rate, specifically, comparing the first actual service rate returned by the queue scheduler in the step S12 with the first reserved service rate by the queue controller, if the former is greater than the latter, entering the step S14, otherwise, entering the step S15.
S14: if the first actual service rate is greater than the first subscribed service rate, the first subscribed service rate is decreased. If the first actual service rate is greater than the first reserved service rate, it indicates that the first actual service rate is too large, for example, the first reserved service rate is 2M, and the first actual service rate is 3M, which may cause a waste of scheduling resources.
As a preferable scheme, the step S14 may specifically include: acquiring a preset fixed delay of a head synchronous message of a time synchronization queue; calculating according to a preset fixed delay to obtain an adjustment quantity of the rate of the reserved service; the first subscribed service rate is decreased in accordance with the subscribed service rate adjustment. Specifically, the maximum service rate, the residual service rate, the preset fixed delay, the first length of each sync message before the head sync message, the second length of a dummy message inserted before each sync message before the head sync message, the third length of each service message contained in a first service queue with a priority higher than that of a time sync queue, the second actual service rate of the first service queue, the fourth length of each service message contained in a second service queue with a priority lower than that of the time sync queue, and the third actual service rate of the second service queue are obtained; firstly, a target actual service rate of the time synchronization queue is calculated according to a preset fixed delay, a first length, a second length, a third length, a fourth length, a second actual service rate and a third actual service rate, and because the following relations exist among the quantities:
the target actual service rate can therefore be calculated using the following formula:
wherein r is
i-real' is the target actual service rate for time synchronization queue i,
is the preset fixed delay of the head synchronization message k of the time synchronization queue i,
is the first length of the kth sync message of time sync queue i,
is the second length of the dummy packet inserted before the kth sync packet,
is the third length of the kth traffic packet contained in the first traffic queue j,
is the fourth length, r, of the kth service packet contained in the second service queue h
j-realIs the second actual service rate, r, of the first traffic queue, j
h-realIs a third actual service rate of the second traffic queue h, k is a positive integer greater than 1, k' is a positive integer greater than 0 and less than k, i is a positive integer greater than 0, j is a positive integer greater than 0 and less than M, and h is a positive integer greater than 0 and less than S. Then, the adjustment amount of the reserved service rate is calculated according to the first reserved service rate, the maximum service rate, the remaining service rate and the target actual service rate, and the following relationship exists among the above quantities:
therefore, the reserved service rate adjustment amount can be calculated using the following formula:
wherein, Δ riIs the reserved service rate adjustment, r, of the time synchronization queue iiIs the first reservation service rate, r, of the time synchronization queue imaxIs the maximum service rate, rremainIs the residual rate, ri-real' is the target actual service rate of time synchronization queue i, i is a positive integer greater than 0, let ri' is the adjusted subscribed service rate, known as ri′=ri+Δri。
S15: further comprising: if the first actual service rate is less than the first reserved service rate, the first reserved service rate is increased. If the first actual service rate is less than the first reserved service rate, which indicates that the first actual service rate is not enough, the first actual service rate can be made to approach the first reserved service rate by increasing the first reserved service rate, so that the synchronous message is ensured to have a certain preset fixed delay in the switch to prevent delay jitter, meanwhile, data transmission errors are avoided, and the queue transfer work is ensured to be normally carried out.
As a preferable scheme, the step S15 may include: acquiring a preset fixed delay of a head synchronous message of a time synchronization queue; calculating according to a preset fixed delay to obtain an adjustment quantity of the rate of the reserved service; the first subscribed service rate is increased in accordance with the subscribed service rate adjustment. That is, the reserved service rate adjustment amount is determined according to the preset fixed delay time of the header synchronization packet, and specifically, the reserved service rate adjustment amount may be calculated in the same manner as the preferred scheme of step S14 in this embodiment, for specific reference to the detailed description of the preferred scheme of step S14 in this embodiment.
As a preferred scheme, the working principle of the time synchronization queue established in this embodiment is: taking a virtual time synchronization queue i belonging to [1, N ] as a reference, expressing a high priority queue with a priority higher than that of the virtual time synchronization queue by using a queue j belonging to [1, M ], expressing a low priority queue with a priority lower than that of the virtual time synchronization queue by using a queue h belonging to [1, S ], entering a queue scheduler according to the priority, when a switch sends a synchronization message and other service messages, determining a sending sequence by a fair scheduling algorithm according to the size of a virtual time mark value VC of each message, and taking the message sending completion as a fair principle; when only a sync message exists in the switch, a dummy message with empty content can be inserted into the time synchronization queue, the length of the dummy message is equal to the bandwidth of the switch multiplied by the waiting time of the dummy message, and the length of the dummy message can be corrected by adopting the following formula to more accurately control the waiting time of the sync message in the time synchronization queue:
wherein,
is in a time synchronization queue iThe length of the dummy packet inserted before the header sync packet k in the invention can reduce the problem of discarding the sync packet at the tail, because the scheme adjusts the reserved service rate, as shown in fig. 3, case1 indicates that when the reserved service rate is not adjusted, the sync packet is in the case of no adjustment of the reserved service rate
(i.e. the kth synchronization packet of the time synchronization queue i) before inserting the PSP packet
(i.e., dummy message) condition, there will be a sync packet
(i.e., the kth' sync message of time sync queue i, with a predetermined fixed delay of
) Discarded, and as shown in case2, the case when the subscribed service rate is adjusted is the case when the sync packet that should be discarded
As the subscribed service rate changes and meets the requirement of the preset fixed delay, the subscribed service rate is not discarded, as shown in fig. 4, the specific implementation flow is as follows:
s401: data packet arrival, i.e. arrival of a data packet (message) at the queue controller;
s402: and acquiring header information for classification, wherein the header information of the synchronous message is the preset identifier 'destination is distinguished'.
S403: and updating the virtual time tag, namely updating the corresponding time stamp according to the specific information of the data packet.
S404: and judging whether the packet is a synchronous packet, namely judging the packet in the data packet according to the header information, if so, entering the step S405, and if not, ending the step.
S405: and if the synchronization message is the synchronization message, controlling the synchronization message to enter a virtual time synchronization queue.
S406: and calculating the adjustment amount of the subscribed service rate.
S407: determining the remaining service rate rremainIf it is equal to 0, the process proceeds to step S411, otherwise, the process proceeds to step S408.
S408: judging the length of a pseudo message inserted before a head synchronous message k of a time synchronization queue i
If not, the process proceeds to step S409 if the value is greater than or equal to 0, otherwise, the process proceeds to step S412.
S409: and inserting a PSP packet in front of the synchronous message.
S410: the PSP packet leaves.
S411: the synchronization message leaves.
S412: and the discard synchronization message is discarded.
The service rate control method for the control plane time synchronization queue provided in this embodiment constructs an independent time synchronization queue, and compares the acquired first actual service rate of the time synchronization queue with the first reserved service rate thereof in real time, when the first actual service rate is not equal to the first subscribed service rate, adjusting the first subscribed service rate in real time according to the requirement to make the first actual service rate approach to the first subscribed service rate, thereby controlling the time of the head synchronous message of the time synchronous queue entering the switching node, so that the synchronous message has a definite preset fixed time delay in the switch, further realizing the effect of preventing time delay jitter, under the condition of not occupying the effective bandwidth of the switch, the aim of consuming the waiting time of the synchronous message is achieved, and the possibility of discarding the synchronous packet at the tail part of the queue is reduced.
Example 2
The present embodiment provides an apparatus for controlling service rate of a control plane time synchronization queue, as shown in fig. 5, the apparatus includes: the system comprises a building module 51, an obtaining module 52, a judging module 53, a decreasing module 54 and an increasing module 55, wherein the main functions of the modules are as follows:
the establishing module 51 is configured to establish the time synchronization queue according to the preset identifier, specifically refer to the detailed description of step S11 in embodiment 1.
The obtaining module 52 is configured to obtain a current first reserved service rate and a first actual service rate of the time synchronization queue, which refer to the detailed description of step S12 in embodiment 1.
The determining module 53 is configured to determine whether the first actual service rate is greater than the first reserved service rate, specifically refer to the detailed description of step S13 in embodiment 1.
The reducing module 54 is configured to reduce the first subscribed service rate if the first actual service rate is greater than the first subscribed service rate, which is described in detail in the step S14 in embodiment 1.
As a preferable scheme, the method further comprises the following steps: an increasing module 55, configured to increase the first subscribed service rate if the first actual service rate is smaller than the first subscribed service rate, see the detailed description of step S15 in embodiment 1.
As a preferred solution, the reduction module 54 comprises: a first obtaining unit 541, configured to obtain a preset fixed delay time of a head synchronization packet of a time synchronization queue; a first calculating unit 542, configured to calculate, according to a preset fixed delay, an adjustment amount of a reservation service rate; a reducing unit 543 for reducing the first subscribed service rate according to the subscribed service rate adjustment amount. See in particular the detailed description of the preferred embodiment of step S14 in example 1.
As a preferred solution, the increasing module 55 comprises: a second obtaining unit 551, configured to obtain a preset fixed delay of a head synchronization packet of a time synchronization queue; a second calculating unit 552, configured to calculate, according to a preset fixed delay, an adjustment amount of a reserved service rate; an increasing unit 553, configured to increase the first subscribed service rate according to the subscribed service rate adjustment amount. See in particular the detailed description of the preferred embodiment of step S15 in example 1.
As a preferred scheme, the step of calculating the reserved service rate adjustment amount according to the preset fixed delay includes: acquiring the maximum service rate, the residual service rate, the preset fixed delay, the first length of each synchronous message before the head synchronous message, the second length of a dummy message inserted before each synchronous message before the head synchronous message, the third length of each service message contained in a first service queue with the priority higher than that of the time synchronous queue, the second actual service rate of the first service queue, the fourth length of each service message contained in a second service queue with the priority lower than that of the time synchronous queue and the third actual service rate of the second service queue of the queue scheduler; calculating a target actual service rate of the time synchronization queue according to a preset fixed delay, the first length, the second length, the third length, the fourth length, the second actual service rate and the third actual service rate; and calculating to obtain the adjustment quantity of the reserved service rate according to the first reserved service rate, the maximum service rate, the residual service rate and the target actual service rate. See in particular the relevant detailed description in example 1.
As a preferred scheme, the target actual service rate is calculated by adopting the following formula:
wherein r is
i-real' is the target actual service rate for time synchronization queue i,
is the preset fixed delay of the head synchronization message k of the time synchronization queue i,
is the first length of the kth sync message of time sync queue i,
is the second length of the dummy packet inserted before the kth sync packet,
is the third length of the kth traffic packet contained in the first traffic queue j,
is the fourth length, r, of the kth service packet contained in the second service queue h
j-realIs the second actual service rate, r, of the first traffic queue, j
h-realIs a third actual service rate of the second traffic queue h, k is a positive integer greater than 1, k' is a positive integer greater than 0 and less than k, i is a positive integer greater than 0, j is a positive integer greater than 0 and less than M, and h is a positive integer greater than 0 and less than S. See in particular the relevant detailed description in example 1.
As a preferred scheme, the reserved service rate adjustment amount is calculated by adopting the following formula:
wherein, Δ riIs the reserved service rate adjustment, r, of the time synchronization queue iiIs the first reservation service rate, r, of the time synchronization queue imaxIs the maximum service rate, rremainIs the residual rate, ri-real' is the target actual service rate of time synchronization queue i, i being a positive integer greater than 0. See in particular the relevant detailed description in example 1.
The service rate control device for the control plane time synchronization queue provided in this embodiment constructs an independent time synchronization queue, and compares the acquired first actual service rate of the time synchronization queue with the first reserved service rate thereof in real time, when the first actual service rate is not equal to the first subscribed service rate, adjusting the first subscribed service rate in real time according to the requirement to make the first actual service rate approach to the first subscribed service rate, thereby controlling the time of the head synchronous message of the time synchronous queue entering the switching node, so that the synchronous message has a definite preset fixed time delay in the switch, further realizing the effect of preventing time delay jitter, under the condition of not occupying the effective bandwidth of the switch, the aim of consuming the waiting time of the synchronous message is achieved, and the possibility of discarding the synchronous packet at the tail part of the queue is reduced.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.