阅读说明：本技术 一种确定性时延业务智能调度与控制实施方法 (Deterministic time delay service intelligent scheduling and control implementation method ) 是由 汪勤思 于 2020-04-19 设计创作，主要内容包括：针对现有网络不能实现确定性时延业务传输,不能满足协作性应用对确定性时延抖动上界的要求,本发明提供一种确定性时延业务智能调度与控制实施方法。该方法通过网络中转发设备管理平面配置确定时延业务以及端到端时延需求,定义传输时确定性时延业务的标识和时间戳信息,网络节点对确定性业务基于时延需求和时钟戳选择转发路径和发送时间片,实现端到端确定性时延。网络节点根据确定性时延业务转发状况,调整转发队列数和调度周期参数,适配确定性时延业务的传输,提高整体传输性能。另外,通过数据包系列号,实现对确定时延业务实现可靠和按序传输机制,通过逐包确认和丢包及超时反馈机制实现可靠传输,并实现确定性时延业务的复制和消除。(The invention provides an intelligent scheduling and control implementation method for deterministic delay service, aiming at the problems that the existing network can not realize deterministic delay service transmission and can not meet the requirement of cooperative application on the upper bound of deterministic delay jitter. The method determines a time delay service and an end-to-end time delay requirement through the configuration of a forwarding device management plane in a network, defines identification and timestamp information of the deterministic time delay service during transmission, and realizes end-to-end deterministic time delay by selecting a forwarding path and sending a time slice for the deterministic service through a network node based on the time delay requirement and a clock stamp. The network node adjusts the number of the forwarding queues and the scheduling period parameter according to the forwarding condition of the deterministic delay service, adapts to the transmission of the deterministic delay service, and improves the overall transmission performance. In addition, a reliable and sequential transmission mechanism for the determined delay service is realized through a data packet serial number, reliable transmission is realized through packet-by-packet confirmation and packet loss and overtime feedback mechanisms, and the copying and elimination of the determined delay service are realized.)

1. A deterministic delay service intelligent scheduling and control implementation method is characterized in that:

defining a deterministic delay service identifier: defining a deterministic time delay service data packet format and adding a service identifier;

and (3) deterministic delay service scheduling and control: the network node selects a forwarding path and a sending time slice for the deterministic service based on the time delay requirement and the clock stamp, so that end-to-end deterministic time delay is realized;

the network node intelligently adjusts transmission scheduling parameters: the network node adjusts the number of forwarding queues and scheduling period parameters according to the forwarding condition of the deterministic delay service, adapts to the transmission of the deterministic delay service and improves the overall transmission performance;

the reliable and sequential transmission mechanism of the determined delay service is realized.

2. The method of claim 1, wherein information of a deterministic latency traffic flow ID, a serial number and a time stamp is recorded by defining an optional T L V of an SRH in SRv 6.

3. The deterministic latency service scheduling and controlling method of claim 1, wherein a deterministic latency service information table is generated by the control plane, the table includes a data stream ID, a fast path latency from the node to the destination node, another slow path latency from the node to the destination node, an end-to-end latency requirement, etc.; and when the forwarding plane receives the data packet, entering a corresponding queue according to the deterministic delay service information table and the timestamp information.

4. The method as claimed in claim 1, wherein the forwarding node control plane reads the statistical information of deterministic service data packets in each queue, performs intelligent dynamic adjustment on the scheduling period and the number of queues according to the statistical result, adjusts the number of queues according to the deviation ratio of the expected forwarding delay, and adjusts the scheduling period value of the queues according to the maximum deterministic service duty ratio.

5. The method according to claim 1, wherein the reliable and sequential transmission mechanism for the deterministic latency services is implemented by a serial number of data packets, the reliable transmission is implemented by a packet-by-packet acknowledgement and packet loss and timeout feedback mechanism, and the duplication and elimination of the deterministic latency services are implemented.

6. The method according to claim 3, wherein the network node calculates the longest and shortest delays for locally forwarding different paths according to the service end-to-end delay requirement, selects an appropriate queue and path according to the remaining delay information, transmits the packet when the time slice arrives, selects the closest time slice queue for transmission if the end-to-end delay requirement cannot be met, and sends feedback information to the source end.

Technical Field

The invention relates to the technical field of network service transmission in communication, in particular to a method for realizing the transmission of deterministic delay service through a router and providing dynamic transmission capability adjustment in network transmission.

Background

With the deployment of 5G, the network bandwidth is no longer a bottleneck, and a large number of collaborative service applications (such as industrial internet, 5G slices, etc.) require to guarantee the worst delay or delay jitter, i.e., deterministic delay.

A deterministic latency network refers to a single domain network with three features: 1) a large number of network devices, 2) a long distance between two network devices, 3) a large number of deterministic data flows in the network.

These features will cause the following problems:

(1) IEEE TSN issued a series of deterministic standards applicable to L AN, most of these standards required L AN for time synchronization between all devices, due to the large number of heterogeneous devices in large-scale networks, maintaining accurate time synchronization between all devices is difficult and costly, so TSN technology cannot be directly applied to large-scale networks, resulting in deterministic delay network architectures that cannot provide bounded delay;

(2) satisfy fast convergence after new service creation: application scenarios such as VR communication may require deterministic communication connections to be established or broken very frequently. Mechanisms that require global recalculation when adding new data streams, such as IEEE 802.1Qbv, are not suitable for large-scale networks;

(3) fine-grained extensible resource reservation: to guarantee the QoS of deterministic flows, the network must make resource reservations for each deterministic flow. All devices on the path should maintain a resource reservation state for each independent deterministic flow. This resource reservation approach is not scalable due to the large number of deterministic flows present on large scale networks;

(4) ignoring long link transmission delay tolerance: IEEE 802.1 Qch proposes a typical and efficient cycle forwarding mechanism that enables end-to-end jitter of less than 2 x T (T being one cycle). But the length of the period T cannot be too large and the link propagation delay cannot be too large. This limitation is not friendly to long haul links in large scale networks.

Therefore, how to implement deterministic delay service transmission based on the existing network technology and ensure an upper bound for deterministic delay jitter is a problem to be urgently solved by those skilled in the art.

Disclosure of Invention

The technical problem to be solved is as follows:

the present invention is directed to overcome the above drawbacks of the background art, and to provide a method for transmitting deterministic delay traffic. Mainly solves the following technical problems: (1) according to the requirement of the service, identifying and marking the deterministic service, and adding timestamp information so as to identify the deterministic delay service in network transmission; (2) the end-to-end transmission delay control of the deterministic delay service is realized; (3) a reliable transmission mechanism is realized for the determined time delay service, and reliable transmission is realized through packet-by-packet confirmation, packet loss and a time delay feedback mechanism; (4) by avoiding out-of-order for in-order transmission, and implementing duplication and elimination of deterministic delay traffic.

The technical scheme for solving the technical problem is as follows:

a management plane of forwarding equipment in a network is configured with a deterministic delay service and an end-to-end delay requirement, the deterministic delay service is defined and identified, and a network node selects a forwarding path and sends a time slice to the deterministic service based on the delay requirement and a clock stamp to realize end-to-end deterministic delay. In addition, the network node adjusts the number of forwarding queues and scheduling period parameters according to the forwarding condition of the deterministic delay service, adapts to the transmission of the deterministic delay service, and improves the overall transmission performance. In addition, a reliable and sequential transmission mechanism for the determined delay service is realized through a data packet serial number, reliable transmission is realized through packet-by-packet confirmation and packet loss and overtime feedback mechanisms, and the copying and elimination of the determined delay service are realized.

And the deterministic delay service identifier is defined, and information such as an ID, a serial number, a timestamp and the like of the deterministic delay service flow is recorded through an optional T L V of the SRH in the definition SRv 6.

The network node schedules and controls the deterministic delay service, and generates a deterministic delay service information table through a control plane, wherein the table comprises a data flow ID, a faster path delay from the node to a destination node, another slower path delay from the node to the destination node, an end-to-end delay requirement and the like. And when the forwarding plane receives the data packet, entering a corresponding queue according to the deterministic delay service information table and the timestamp information.

The data packet enters a corresponding queue according to a deterministic delay service information table and timestamp information, the network node calculates the longest and shortest delays of different local forwarding paths according to the service end-to-end delay requirement, selects a proper queue and path according to the residual delay information, transmits the data packet when a time slice arrives, selects the closest time slice queue for transmission if the end-to-end delay requirement cannot be met, and sends feedback information to a source end.

The network node intelligently adjusts transmission scheduling parameters, namely a forwarding node control plane reads statistical information of deterministic service data packets of each queue, intelligently and dynamically adjusts a scheduling period and the number of the queues according to a statistical result, adjusts the number of the queues according to a deviation ratio of expected forwarding time delay, and adjusts a scheduling period value of the queues according to a maximum deterministic service occupation ratio.

The method for realizing the reliable and sequential transmission mechanism of the determined time delay service realizes the reliable and sequential transmission mechanism of the determined time delay service through a data packet serial number, realizes the reliable transmission through packet-by-packet confirmation, packet loss and overtime feedback mechanisms, and realizes the copying and elimination of the determined time delay service.

The invention has the beneficial effects that:

compared with the prior art, the method and the device can meet the requirement of the service on the certainty of the time delay. The method comprises the steps that timestamp information, a flow ID and a serial number are added to a deterministic service data packet, when the network transmission equipment forwards the data packet, the data packet enters a corresponding transmission queue according to the timestamp information of the data packet and the time delay requirement of the service, so that the data packet forwarding time delay control is realized, the deterministic time delay transmission requirement is met, the data packet which cannot meet the time delay requirement is transmitted according to the most appropriate queue (time delay) requirement and is fed back upstream and cannot be met, and therefore a whole network controller can adjust according to the network transmission condition. In the transmission process of the deterministic delay service, each key node confirms through a feedback mechanism, the replication and elimination of the deterministic service are realized according to the serial number, and meanwhile, each network node intelligently adjusts the time slice rotation scheduling period and the queue number according to the forwarding condition of the deterministic delay service.

Drawings

Fig. 1 is a schematic diagram of deterministic latency service scheduling and control implementation of the present invention.

Fig. 2 is a schematic diagram of SRv 6-based deterministic latency traffic packets.

Fig. 3 is a flow chart of the deterministic latency scheduling and control implementation of the present invention.

Fig. 4 is a flow chart of the deterministic latency service transmission forwarding plane of the present invention.

FIG. 5 is a flow chart illustrating intelligent adjustment of scheduling and control parameters according to the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and the embodiments.

The invention is a method for realizing deterministic delay service scheduling and control by network equipment in a deterministic network, in the method, each router control plane in the network notifies a deterministic delay service parameter to a router on a transmission path and issues the related parameter to a forwarding plane, and the forwarding plane forwards the deterministic delay service parameter according to the issued parameter. During transmission, the forwarding of a router in the network is divided into transmission periods (such as 200 ns) according to time, and within a fixed time slice (such as 10ns) of the transmission periods, the deterministic delay service is forwarded based on time slice round-robin scheduling.

Referring to fig. 1, a schematic diagram of deterministic delay service scheduling and control implementation is shown, in the method of the present invention, a router control plane includes a network management configuration module, a routing protocol, and a control information processing module. The network management configuration module mainly realizes the configuration of the deterministic delay service, the routing protocol module broadcasts the configuration information of the deterministic service to other equipment in the network, and the control information processing module realizes the intelligent adjustment of the deterministic service queue and the transmission period.

The forwarding plane of the invention comprises a data stream forwarding delay information table, a data stream receiving and sending information table, a scheduling queue, data stream packet receiving information and the like. The data flow forwarding delay information table mainly records and determines delay service related information, and the information is issued by a control plane; the data flow receiving and transmitting information table records the information in the deterministic delay service forwarding process; the scheduling queue realizes data packet forwarding caching, and data packets in different queues are scheduled by a time slice rotation-based scheduling queue for forwarding scheduling; the data flow packet receiving information module is mainly used for processing feedback information sent to an upstream node, wherein the feedback information comprises retransmission, packet receiving confirmation and the like.

Referring to fig. 2, a schematic diagram of a deterministic latency service packet based on SRv6, in order to ensure the transmission of deterministic latency service and to be compatible with existing networks, 16 bytes of option t L V in SRH are modified from optional fields in the SRH field of SRv6 data packet for recording the following information:

type: 8 bits (1 byte) to distinguish this field for deterministic latency traffic;

length L ength is 8bit (1 byte), records the length increased by the determinacy service head field, the unit is byte, and is fixed as 16;

stream ID: 20 bits, representing deterministic traffic;

sequence number: 28 bits, a packet series number representing deterministic traffic;

clock stamping: and 64 bits, which represents time information when the deterministic service packet starts to be transmitted.

When the deterministic service enters the network for transmission, the information is filled when the source end generates a data packet. If the source end does not support the SRH information setting, when the access router receives the deterministic delay service data packet, the SRH of the deterministic service is modified, and the type, the length, the stream ID, the serial number and the clock stamp information are added according to the format.

Referring to fig. 3, a flowchart of deterministic latency scheduling and control implementation is shown, and a specific process flow is as follows.

Step S1: configuring deterministic delay traffic and related parameters

The method comprises the steps that a network management configures the data flow ID, source and destination addresses, service bandwidth requirements and delay jitter requirements of deterministic delay service on an access router, the end-to-end delay requirements of the service are notified to other routers of a network through a routing protocol, or a cloud management platform issues the data flow ID, the source and destination addresses and the delay requirements of the deterministic service to all routers in the network through an SDN controller.

Step S2: router control plane generates deterministic delay service information table

After receiving the deterministic delay service information, the router node management plane in the network calculates the relevant information of the deterministic delay service and generates the following deterministic delay service forwarding information table: the method comprises the steps of data flow ID, time delay t1 from a source end to a forwarding node, forwarding time delay t2 of the node, time delay t3 of a fast path p1 from the node to a destination node, time delay t4 of another slow path p2 from the node to the destination node and an end-to-end time delay value t.

Step S3: router scheduling of deterministic latency traffic data streams

In a router forwarding plane, an egress direction is scheduled strictly according to a time slice round robin through 4 buffer queues, a data packet in a 1 st queue is forwarded (currently being forwarded) in a 1 st period (T1), a data packet in a 2 nd queue is forwarded in a 2 nd period (T2 =2T 1), a data packet in a 3 rd queue is forwarded in a 3 rd period (T3 =3T 1), a data packet in a 4 th queue has no fixed forwarding period, when no data packet is forwarded in the first three periods, the data packet in the queue is forwarded, and the forwarding time duration is the remaining time slice of the period.

Step S4: router for deterministic delay service transmission

When the router receives the deterministic delay data packet, the method for placing the data packet into the transmission queue comprises the following steps:

calculating the actual time delay t5 from the data packet to the local through the clock information and the local clock information carried in the data packet SRH;

calculating the longest and shortest time delays of local forwarding according to the actual time delay t5, wherein the shortest local time delay t00= (t-t 5-t 4), and the longest local time delay t01= (t-t 5-t 3);

selecting a proper forwarding queue and path, and if the shortest local delay meets T1< T00<3T1, selecting the 2 nd or 3 rd queue, wherein the forwarding path is p 2; if the longest local time delay meets T1< T01<3T1, selecting the 2 nd or 3 rd queue, and the forwarding path is p 1;

if the requirement of the step 5 can not be met, feedback control needs to be sent to the source end; if T00< T1, then select the 2 nd queue (early forwarding) and fast path p 1; if T01>3T1, then select the 3 rd queue (late forwarding) and slow path p 2; other cases select the 2 nd queue (early forwarding) and fast path p 1.

Referring to fig. 4, a flow chart of the deterministic latency service processing by the forwarding plane is shown, and the following contents are described in detail.

Step S5: router intelligent regulation scheduling period and queue number

The statistical information of the deterministic service data packets of each queue is read on the control plane, and the scheduling period and the queue number are intelligently and dynamically adjusted according to the statistical result in a longer time, so that the intelligent queue scheduling based on the time stamp is more reliable, and the accurate forwarding time delay of most deterministic service data packets in the equipment is realized. Referring to fig. 5, a flowchart of the intelligent adjustment of the deterministic latency traffic scheduling period and the number of queues is shown, and the following contents are described in detail.

Referring to fig. 4, which is a flow chart of a deterministic latency service transmission and forwarding plane, a specific processing flow of each router on a deterministic latency service data packet is as follows.

Step S401: and when the data packet is received, judging whether the data packet is a deterministic delay service data packet or not according to the type information in the data packet SRH.

Step S402: if the packet is a deterministic delay service packet, extracting the stream ID and the serial number of the packet, and if the packet is a repeated packet or a disordered packet, discarding the packet and sending a disordered feedback packet.

Step S403: and for the deterministic delay service message, calculating the delay through local clock information and the timestamp in the data packet, and calculating the minimum delay and the maximum delay of the node forwarding according to the data stream forwarding delay information table.

Step S404: judging whether a router forwarding queue meets the delay requirement of a deterministic delay service data packet or not for the deterministic delay service message, if not, putting the router forwarding queue into an earliest forwarding queue if the minimum delay is less than the fastest forwarding queues of all queues; if the minimum time delay is larger than the slowest forwarding queues of all queues, putting the slowest forwarding queue into the time delay latest forwarding queue; and sends feedback information upstream.

Step S405: for the deterministic delay service message, if a proper forwarding queue meets the requirement of the deterministic delay service, the data packet is put into a corresponding position of a corresponding packet receiving sequence entering queue according to delay information, the message is sent to an output port through a round-robin scheduling queue mechanism, and if a plurality of output ports are provided, the message is sent to each port.

Step S406: and for the non-deterministic delay service message, if the message is not a confirmation message sent by the downstream, putting the data packet into other data packet sending queues, and sending the message to an output port.

Step S407: if the packet is the acknowledgement packet sent by the downstream, for the packet needing to be retransmitted, finding the retransmission packet from the deterministic service unacknowledged packet queue and putting the retransmission packet into the earliest forwarding queue. And deleting the corresponding data packet in the unacknowledged service packet queue for the deterministic service acknowledgement message.

In step 5, the router intelligently adjusts the scheduling period and the number of queues, and referring to fig. 5, a flowchart of intelligently adjusting the scheduling and control parameters is shown, and the specific processing flow is as follows.

Step S501: when the data packet is forwarded, the forwarding time delay tz of the deterministic service data packet in the device is recorded, the deviation ratio of the expected forwarding time delay t2 of the node, namely (tz-t 2)/t 2, is calculated, and the calculation is carried out according to 7 grades of-50%, -30%, -10%,10%,30% and 50%.

Step S502: if the deterministic data packet statistics are mainly concentrated in the area smaller than 0, the fact that the forwarding delay of most data packets is smaller than the expected value is shown, the number of queues can be reduced, and if the deterministic data packet statistics are mainly concentrated in the area larger than 0, the number of queues is increased, and finer deterministic service delay scheduling is carried out.

Step S503: when the data packet is forwarded, the sum of the forwarding time of the deterministic service data packet in one period of each queue is recorded, and the proportion qi (wherein i is a queue number) of the scheduling time occupied by the deterministic service is calculated in a period of time.

Step S504: if the maximum deterministic traffic fraction qi exceeds 90%, indicating that the queue is in a saturated state, and increasing a queue scheduling period value T; if the maximum difference between the different queue deterministic traffic fractions qi exceeds 50%, the queue scheduling period value T is decreased.

In order to further ensure the certainty of the service delay and the sequential transmission, and realize the reliability of the deterministic delay service, in addition to the foregoing, the router needs to perform the following processing:

1: hop-by-hop acknowledgement and packet loss feedback: after receiving and forwarding the deterministic delay service data packet, the segment routing node performs delay confirmation on the sequentially arriving packet, namely, in a period, counting the serial numbers of the received packets of the same flow ID, uniformly performing primary confirmation on the data packets which are transmitted in sequence upstream, and deleting the cache queue after the data packets are received by the upstream. When the scheduling is out of order, immediate confirmation is carried out, namely missing data packets are immediately sent to an upstream node, so that the upstream node can retransmit as soon as possible, and larger time delay jitter caused by packet loss is reduced;

2. time delay feedback: when the deterministic delay service enters a queue, if the queue is full or no proper queue enters the queue, sending back pressure to the initial node of the service flow, and limiting the speed of the service flow or reselecting a path;

3. dithering: when a deterministic delay service data packet enters a queue, recording a sequence number, and inserting according to the sequence number to ensure the sequential transmission of the same service;

4. a feedback mechanism: for the data packet which can not meet the delay requirement, the data packet is sent to the earliest forwarding queue, meanwhile, feedback information is sent to the upstream, after the upstream node receives the feedback information, the service delay requirement is dynamically promoted, and the intermediate node promotes the priority of the service;

5. eliminating: the data packets with the same flow ID are transmitted according to the serial number, only one data packet is forwarded for the data packets with the same serial number, and redundant data packets are discarded;

6. copying: when multiple paths exist for the deterministic delay service with the same ID, the deterministic delay service needs to be copied;

7. and (3) stream bandwidth reservation: for the deterministic delay service needing bandwidth reservation, a packet receiving queue is separately set, but the length of the queue and the requirement are calculated according to the reserved bandwidth.

The present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the principle of the present invention, and such modifications and improvements are also considered to be within the scope of the present invention.

Those not described in detail in this specification are within the skill of the art.