WO2021051418A1

WO2021051418A1 - Methods and network nodes for reliability measurement

Info

Publication number: WO2021051418A1
Application number: PCT/CN2019/107128
Authority: WO
Inventors: Tal Mizrahi; Feili QIAN; Xiaoping Zhu; Dani LIU; Ronen Hyatt
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2019-09-21
Filing date: 2019-09-21
Publication date: 2021-03-25
Also published as: CN114073049A; CN114073049B

Abstract

The present disclosure relates to the field of computer networks. More specifically, the present disclosure relates to packet loss detection in such networks. The present disclosure provides a network node for reliability measurement of a network, wherein the network node is configured to obtain a packet, wherein the packet relates to a flow being transferred in the network and comprises a reliability measurement field; to obtain packet count information of the network node, wherein the packet count information represents a number of packets of the flow forwarded by the network node; to insert the packet count information of the network node to the reliability measurement field; and to forward the packet to a next hop of the network node.

Description

METHODS AND NETWORK NODES FOR RELIABILITY MEASUREMENT

TECHNICAL FIELD

The present disclosure relates to the field of computer networks. More specifically, the present disclosure relates to packet loss detection in such networks. A network node is provided, which allows for in-band packet loss measurement across multiple hops. The present disclosure also relates to an evaluation device, and an ingress as well as an egress node, which assist the above network node.

BACKGROUND

Performance measurement and network telemetry are critical capabilities in communication networks. One of the most important aspects of performance monitoring is packet loss measurement, i.e. the ability to detect and measure the number of packets that are dropped by network devices. Specifically, it is important to be able to detect the precise location (the specific network device or node) , in which packets are dropped.

Existing solutions for loss measurement use a point-to-point approach, such that the number of dropped packets is measured between two specific devices or endpoints in the network. The problem that such a solution faces, is that it is difficult to determine a precise location where a packet is dropped.

SUMMARY

In view of the above-mentioned problem, embodiments of the present invention aim to improve the conventional solutions for loss measurement.

It is an objective to allow for measurement of packet loss along a network path on a hop-by-hop basis, and specifically to enable a detection of the location of packet drops.

The objective is achieved by the embodiments of the invention as described in the enclosed independent claims. Advantageous implementations of the embodiments of the invention are further defined in the dependent claims.

A first aspect of the present invention provides a network node for reliability measurement of a network, wherein the network node is configured to obtain a packet, wherein the packet relates to a flow being transferred in the network and comprises a reliability measurement field; obtain packet count information of the network node, wherein the packet count information represents a number of packets of the flow forwarded by the network node; insert the packet count information of the network node to the reliability measurement field; forward the packet to a next hop of the network node.

This is beneficial as the packet includes a reliability measurement field, packet count information of the network node is obtained for the packet and inserted to the reliability measurement field, this reliability measurement field allows for determining the position of packet loss in a network.

In particular, the network node for reliability measurement may also be called transit node, or forwarding node.

In particular, the forwarding node is a switch, a router, a middle box, a network interface controller, NIC, or any device that can send, receive, and/or forward packets.

In particular, the reliability measurement field is a field that includes an entry with reliability information (that is packet count information) for each node along a path of the network. In particular, the reliability measurement field may be updated by each node along the path.

In particular, the packet count information includes a count value of the total number of packets of the common flow which were forwarded by the network node.

In particular, the next hop of the network node is a network node to which the packet is forwarded.

In an implementation form of the first aspect, the packet is obtained from a last hop of the network node.

In particular, the last hop of the network node is a network node that forwarded the packet to the network node for reliability measurement.

In a further implementation form of the first aspect, the obtained packet count information further comprises a first identifier, wherein the first identifier is obtained by increasing, by 1, an identifier of packet count information of the network node of the last hop.

This is beneficial as it allows for determining the position of packet loss in a network based on the above identifier.

In particular, the identifier of packet count information of the network node of the last hop is already present in packet count information in the packet obtained by the network node.

In particular, the identifier is greater than a largest identifier of packet count information that is included in the reliability measurement field of the obtained packet.

In particular, the identifier is an integer. In particular, the identifier of the obtained packet count information is larger, by the numerical value of 1, compared to the largest identifier of packet count information that is already present in the obtained packet.

In particular, the flow comprises a set of packets with common characteristics.

In particular, the characteristics include at least one of: a source IP, a destination IP, a source port, a destination port, a protocol type, a multi-cast group, a broadcast domain.

In a further implementation form of the first aspect, the network node is further configured to provide the obtained packet count information to an evaluation node.

A second aspect of the present invention provides a network node for preparing a packet for reliability measurement of the network, wherein the network node is configured to obtain the packet from a source node; add a reliability measurement field to the packet, wherein the reliability measurement field comprises initial packet count information; and forward the packet to a network node for reliability measurement.

This is beneficial as it supports determining the position of packet loss in a network.

In particular, the network node for preparing the packet for performance measurement may also be called ingress node.

In particular, the ingress node is a switch, a router, a middle box, a network interface controller, NIC, or any device that can send, receive, and/or forward packets.

In an implementation form of the second aspect, the initial packet count information further comprises a second identifier, wherein the second identifier specifies an order number of the network node for preparing a packet for reliability measurement among hops in the network.

This is beneficial as it supports determining the position of packet loss in a network, based on the second identifier.

In particular, the second identifier e.g. is 0 or 1. In particular, the second identifier indicates a starting point of a network path for which reliability is measured.

In particular, the second identifier of the network node for preparing a packet for reliability measurement is the first identifier of the network node for reliability measurement.

A third aspect of the present invention provides a network node for completing reliability measurement of a network, wherein the network node is configured to obtain a packet from a network node for reliability measurement, wherein the packet comprises a reliability measurement field comprising packet count information of one or more network nodes by which the packet was passed in the network; remove the reliability measurement field from the packet; provide the reliability measurement field to an evaluation node, and forward the packet to a destination node.

In particular, the network node for completing performance measurement may also be called egress node.

In particular, the egress node is a switch, a router, a middle box, a network interface controller, NIC, or any device that can send, receive, and/or forward packets.

In particular, the network node is configured to provide the reliability measurement field to the evaluation node together with the packet.

In particular, the network node is configured to provide the reliability measurement field to the evaluation node together with a truncated part of the packet.

In particular, the packet is forwarded to a destination indicated in the packet.

In an implementation form of the third aspect, the obtained packet count information further comprises an identifier of the obtained packet count information.

This is beneficial as it supports determining the position of packet loss in a network, based on the above identifier.

In particular, the identifier of the obtained packet count information corresponds to the above the first identifier, or the above second identifier.

A fourth aspect of the present invention provides an evaluation node for reliability measurement of a flow in a network, wherein the evaluation node is configured to: obtain a first reliability measurement field relating to a first packet and a second reliability measurement field relating to a second packet from an egress network node, wherein the first reliability measurement field comprises a first packet count information and wherein the second reliability measurement field comprises a second packet count information; and evaluate a reliability of the flow, based on the first packet count information and the second packet count information.

This is beneficial as it determining the position of packet loss in a network.

In particular, the egress network node is the network node for completing reliability measurement.

In an implementation form of the fourth aspect, an identifier of the second packet count information is identical to an identifier to the first packet count information and the evaluation node is further configured to detect packet loss based on a difference of a count value of the second packet count information and a count value of the first packet count information.

This is beneficial as it supports determining the position of packet loss in a network, based on the above identifiers.

In particular, the second packet is immediately subsequent to the first packet.

In particular, the second packet count information entry relates to a node that is immediately subsequent to a node to which the first packet count information entry relates. Both nodes are located along a common network path.

In particular, packet loss is detected if the difference of the count value of the second packet count information entry and the count value of the first packet count information entry is greater than 1.

A fifth aspect of the present invention provides a method for reliability measurement, wherein the method comprises: obtaining, by a network node, a packet, wherein the packet relates to a flow being transferred in the network and comprises a reliability measurement field; obtaining, by the network node, packet count information of the network node, wherein the packet count information represents a number of packets of the flow forwarded by the network node ; inserting, by the network node, the packet count information of the network node to the reliability measurement field; forwarding, by the network node, the packet to a next hop of the forwarding network node.

In particular, the packet is obtained from a network node for preparing a packet for reliability measurement. In particular, the packet is forwarded to a network node for completing reliability measurement.

In an implementation form of the fifth aspect, the packet is obtained from a last hop of the network node.

In a further implementation form of the fifth aspect, the obtained packet count information further comprises a first identifier, wherein the first identifier is obtained by increasing by 1 an identifier of packet count information of the network node of the last hop.

In a further implementation form of the fifth aspect, the network node provides the obtained packet count information to an evaluation node.

The fifth aspect and its implementation forms include the same advantages as the first aspect and its respective implementation forms.

A sixth aspect of the present invention provides a method for preparing a packet for reliability measurement, wherein the method comprises obtaining, by a network node, the packet from a source node; adding, by the network node, a reliability measurement field to the packet, wherein the reliability measurement field comprises initial packet count information; and forwarding, by the network node, the packet to a network node for reliability measurement.

In particular, the packet is forwarded to a network node for reliability measurement. In particular, the network node for reliability measurement obtains the packet count information and adds the packet count information as an entry to the reliability measurement field.

In an implementation form of the sixth aspect, the initial packet count information further comprises a second identifier, wherein the second identifier specifies an order number of the network node for preparing a packet for reliability measurement among hops in the network.

The sixth aspect and its implementation forms include the same advantages as the second aspect and its respective implementation forms.

A seventh aspect of the present invention provides a method for completing reliability measurement, wherein the method comprises obtaining, by a network node, a packet from a network node, wherein the packet comprises a reliability measurement field comprising packet count information of one or more network nodes by which the packet was passed in the network; removing, by the network node, the reliability measurement field from the packet; providing, by the network node, the reliability measurement field to an evaluation node; and forwarding, by the network node, the packet to a destination node.

In particular, the packet is obtained from a network node for reliability measurement. In particular, the network node for reliability measurement obtains the packet count information and adds the packet count information as an entry to the reliability measurement field.

In an implementation form of the seventh aspect, the obtained packet count information further comprises an identifier of the obtained packet count information.

The seventh aspect and its implementation forms include the same advantages as the third aspect and its respective implementation forms.

An eighth aspect of the present invention provides a method for reliability measurement of a flow in a network, wherein the method comprises: obtaining, by an evaluation node, a first reliability measurement field relating to a first packet and a second reliability measurement field relating to a second packet from an egress network node, wherein the first reliability measurement field comprises a first packet count information and wherein the second reliability measurement field comprises a second packet count information; and evaluating, by the evaluation node, a reliability of the flow, based on the first packet count information and the second packet count information.

In particular, the packet is obtained from a network node for completing reliability measurement.

In an implementation form of the eighth aspect, an identifier of the second packet count information is identical to an identifier to the first packet count information and the evaluation node is further configured to detect packet loss based on a difference of a count value of the second packet count information and a count value of the first packet count information.

The eighth aspect and its implementation forms include the same advantages as the fourth aspect and its respective implementation forms.

A ninth aspect of the invention suggests a computer program product comprising computer readable code instructions which, when run in a computer will cause the computer to perform the method according to any one of the embodiments of the fifth aspect, the sixth aspect, the seventh aspect, or the eighth aspect of the invention.

A tenth aspect of the invention suggests a computer readable storage medium comprising computer program code instructions, being executable by a computer, for performing a method according to any one of the embodiments of the fifth aspect, the sixth aspect, the seventh aspect, or the eighth aspect of the invention when the computer program code instructions runs on a computer. The computer readable storage medium, comprises of one or more from the group: ROM (Read-Only Memory) , PROM (Programmable ROM) , EPROM (Erasable PROM) , Flash memory, EEPROM (Electrically EPROM) and hard disk drive.

An eleventh aspect of the invention suggests an apparatus for reliability measurement of a network includes a processor and a memory. The memory is storing instructions that cause the processor to perform the method according to the fifth aspect of the invention.

A twelveth aspect of the invention suggests an apparatus for reliability measurement of a network includes a processor and a memory. The memory is storing instructions that cause the processor to perform the method according to the sixth aspect of the invention.

A thirteenth aspect of the invention suggests an apparatus for reliability measurement of a network includes a processor and a memory. The memory is storing instructions that cause the processor to perform the method according to the seventh aspect of the invention.

A fourteenth aspect of the invention suggests an apparatus for reliability measurement of a network includes a processor and a memory. The memory is storing instructions that cause the processor to perform the method according to the eighth aspect of the invention.

In summary, the embodiments of the invention provide a solution for packet loss measurement, measuring the number of dropped packets in each hop along a network path of a given traffic flow. The measurement solution may require each network device along a network path to maintain a packet counter of a given traffic flow that is measured. When a data packet traverses the network path, each device may push the value of its counter into the header of the data packet. At the end of the path, all the counters of the network devices along the path may be available to an evaluation solution that analyzes the counters. These per-hop counters then allow for measuring the number of lost packets in each hop since a previously received packet.

It has to be noted that all devices, elements, units and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application as well as the functionalities described to be performed by the various entities are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity which performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof.

BRIEF DESCRIPTION OF DRAWINGS

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

FIG. 1 shows a schematic view of a network node for reliability measurement according to an embodiment of the present invention.

FIG. 2 shows a schematic view of a network node for reliability measurement according to an embodiment of the present invention in more detail.

FIG. 3 shows a schematic view of a network node for preparing a packet for reliability measurement according to an embodiment of the present invention.

FIG. 4 shows a schematic view of a network node for preparing a packet for reliability measurement according to an embodiment of the present invention in more detail.

FIG. 5 shows a schematic view of a network node for completing reliability measurement according to an embodiment of the present invention.

FIG. 6 shows a schematic view of a network node for completing reliability measurement according to an embodiment of the present invention in more detail.

FIG. 7 shows a schematic view of an evaluation node for reliability measurement according to an embodiment of the present invention.

FIG. 8 shows a schematic view of an evaluation node for reliability measurement according to an embodiment of the present invention in more detail.

FIG. 9 shows an operating example according to the present invention.

FIG. 10 shows a schematic view of a packet according to the present invention.

FIG. 11 shows a schematic view of packets according to the present invention.

FIG. 12 shows a schematic view of a method according to an embodiment of the present invention.

FIG. 13 shows a schematic view of a method according to an embodiment of the present invention.

FIG. 14 shows a schematic view of a method according to an embodiment of the present invention.

FIG. 15 shows a schematic view of a method according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Illustrative embodiments of method, and apparatus for managing data of a plurality of files within one or more file-systems 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.

FIG. 1 shows a schematic view of a network node 100 according to an embodiment of the present invention. The network node 100 is for reliability measurement of a network, in particular for packet loss detection in the network.

To this end, the network node 100 is configured to obtain a packet 101, which relates to a specific flow that is forwarded in the network. The packet 101 that is obtained comprises a reliability measurement field 102. The reliability measurement field 102 can e.g. be inserted in the packet by a previous node in the path, as e.g. the ingress node, which is going to be described below.

The network node 100 is further configured to obtain packet count information 103 of the network node 100, wherein the packet count information 103 represents a number of packets of the flow forwarded by the network node 100. That is, the network node 100 counts the forwarded packets relating to the flow.

Then, the packet count information 103 of the network node 100 (that is, the counted number of packets) is inserted to the reliability measurement field 102. In turn, the packet 101 is forwarded to a next hop of the network node 100. The next hop of the network node 100 can e.g. be a network node following in the network path of the flow. A final hop of the flow which is to be monitored can e.g. be an egress node, as it is also going to be described below.

FIG. 2 shows a schematic view of a network node 100 according to an embodiment of the present invention in more detail. The network node 100 of FIG. 2 builds on the network node 100 of FIG. 1 and therefore includes all of its features and functions.

As it is illustrated in FIG. 2, when obtaining the packet count information 103, the network node 100 can also obtain a first identifier 201. The first identifier can be regarded as an index value, or simply a numbering of the packet count information 103. To obtain the first identifier 201, the network node 100 looks for other identifiers (that is, for other index numbers of packet count information 103 in the reliability measurement field 102) in the reliability measurement field 102, which relate to previous nodes of the path of the packet 101. The value of the first identifier 201 is then obtained by adding 1 to the largest identifier that is found.

Optionally, the network node 100 also can directly provide the obtained packet count information 103 to an evaluation node (which is going to be described below) for evaluation of network reliability.

FIG. 3 shows a network node 300 according to an embodiment of the present invention. The network node 300 is for preparing a packet 301 for reliability measurement.

The network node 300 may also be called ingress node. The network node 300 obtains a packet 301 from a source node. The network node 300 then adds a reliability measurement field 302 to the packet 301. The reliability measurement field 302 comprises initial packet count information 303. The initial packet count information is e.g. the packet count information 303 which was counted by the network node 300. Then, the packet 301 is forwarded to a network node 100 for reliability measurement. The packet 301 which is forwarded to the network node 100 is the packet 101 which is obtained by the network node 100 in FIG. 1.

In other words, the ingress node pushes the following measurement-related data into all or a subset of the data packets that are forwarded through it: a measurement-related header (e.g. the reliability measurement field 302) . A counter (e.g. the initial packet count information 303) , in particular a packet counter that represents the number of data packets belonging to the current traffic flow. This counter is incremented for each data packet that traverses the network node 100. Optionally other measurement-related fields.

FIG. 4 shows a schematic view of a network node 300 according to an embodiment of the present invention in more detail. The network node 300 of FIG. 4 builds on the network node 300 of FIG. 3 and therefore includes all of its features and functions.

As shown in FIG. 4, the initial packet count information 303 further can comprise a second identifier 401. The second identifier 401 of FIG. 4 in particular is the first identifier 201 of FIG. 2. The second identifier 401 may be regarded as the initial counter index of the initial packet count information 303. That is, if the initial counter index (that is, the second identifier 401) is 1, than the next hop along the path may add a packet count information 103 entry in the reliability measurement field 102 whose first identifier 201 (i.e. whose count index) is 2. The next node along the path adds a packet count information 103 entry whose first identifier 201 (i.e. whose count index) is 3, and so on.

FIG. 5 shows a network node 500 according to an embodiment of the present invention. The network node 500 is for completing reliability measurement.

To this end, the network node 500 obtains a packet 501 from the network node 100. The packet 501 which is obtained in particular is the packet 101 which is forwarded by the network node 100 of FIG. 1. The packet 501 comprises a reliability measurement field 502 with packet count information 503 of one or more network nodes by which the packet was forwarded in the network. These field and information also relate to the corresponding entities of FIG. 1.

To complete reliability measurement, the network node 500 removes the reliability measurement field 502 from the packet and provides the reliability measurement field 502 to an evaluation node 700, which is going to be described below. In turn, the packet 501 is forwarded to a destination node. That is that packet according to the above figures in sent from a source node to a destination node (that is, along a specific network path) , wherein the reliability measurement takes place between an ingress node 300 and an egress node 500 (this measurement path partially overlaps with the above mentioned specific network path) .

In other words, the egress node, performs the following: exporting the measurement data to a detection module. Removing the measurement data from the packet and forwarding the packet towards its destination. The egress node optionally can also push a counter into the measurement data, that is, can perform the function of the network node 100 (which is also called the transit node) .

FIG. 6 shows a schematic view of a network node 500 according to an embodiment of the present invention in more detail. The network node 500 of FIG. 6 builds on the network node 500 of FIG. 5 and therefore includes all of its features and functions.

As it is shown in FIG. 6, also the packet count information 503 obtained by the network node 500 comprises an identifier 601. This identifier 601 is the identifier 201 of the network node 100 of FIG. 2.

FIG. 7 shows an evaluation node 700 according to an embodiment of the present invention. The evaluation node 700 is reliability measurement, which is for determining and measuring packet loss along the network path of the packet of the flow.

To this end, the evaluation node 700 obtains a first reliability measurement field 701. This field relates to a packet which was e.. forwarded by the network node 100. The evaluation node 700 also obtains a second reliability measurement field 702, which e.g. relates to a packet, which was e.g. forwarded by another instance of a network node 100. The first and second reliability measurement fields 701, 702 are in particular provided by the egress node, which is by the network node 500.

The first reliability measurement field 701 comprises a first packet count information 703 and the second reliability measurement field 702 comprises a second packet count information 704. The evaluation node 700 then evaluates a reliability of the flow to which the packets below, based on the first packet count information 703 and the second packet count information 704.

The evaluation module 700 can also be called detection module, which is used for detecting and locating packet drops. The detection module may be an external node, or may be an internal module in the egress node. The detection module may be used for detecting per-hop packet loss by comparing the counter value of hop m along the path with the counter value of the same hop m from the previous packet. If no packets were lost the difference should be one. The difference is the number of packets that were lost plus one. By repeating the process for each hop along the path, the detection module can compute the number of dropped packets in each hop along the path.

Upon detecting packet loss, the detection module can report to a user or to a management system, or can trigger fine-grained measurement to detect the location of the problem, e.g. In situ Operations, Administration and Maintenance (IOAM) , or can take a corrective action, such as reconfiguration of a network path.

FIG. 8 shows a schematic view of an evaluation node 700 according to an embodiment of the present invention in more detail. The evaluation node 700 of FIG. 8 builds on the evaluation node 700 of FIG. 7 and therefore includes all of its features and functions.

As shown in FIG. 8, both the first packet count information 703 and the second packet count information 704 can include an

identifier

801, 802 each. During evaluation, an identifier 801 of the second packet count information 704 is identical to an identifier 802 to the first packet count information 703. That is, the packet count information obtained at one specific node is compared for two different packets. E. g. if values of the

identifiers

801 and 802 both are “3” , than the third hop between the ingress node and the egress node is looked at.

Packet loss is in particular detected based on a difference of a count value of the second packet count information 704 and a count value of the first packet count information 703.

For example, if at the third hop between the ingress node the difference between the second packet count information 704 and the first packet count information 703 of two immediately subsequent packets of the same flow is larger than “1” , then packet loss occurred.

FIG. 9 shows an example scenario of operating the network node 100 for reliability measurement, network node 300 for preparing a packet 301 for reliability measurement, the network node 500 for completing reliability measurement, and the evaluation node 700 for reliability measurement.

As shown in FIG. 9, performance measurement is performed between a network node 300 for preparing a packet 301 for reliability measurement (which can also be called ingress node) and a network node 500 for completing reliability measurement (which can also be called egress node) . The ingress node is the first node along the path that takes part in the measurement method, and the egress node is the last node along the path that takes part in the measurement method.

The present invention generally works with packets, in particular with data packets and/or control packets. Data packets are packets that are sent from a source host to a destination host, as opposed to control packets, which are sent between network devices.

The ingress node may push counters (that is, the initial packet count information 303) and possibly other measurement data into data packets.

The egress node may remove the measurement data pushed by the ingress node, and forwards data packets towards their destination.

Transit nodes (such as the network node 100 for reliability measurement) are nodes along the path that may push additional data or update the existing data (that is, the packet count information 103) .

The detection module (which can also be called evaluation node 700) is a module that is used for detecting performance degradation. It may run on a remote server, or may run locally as a module inside the egress node.

Network devices which can implement the above nodes may be switches, routers, middle boxes, NICs, or any device that forwards packets.

Although this is not shown in FIG. 9, optionally, each node along the path, upon receiving a packet with a reliability measurement field can exports the packet count information to the detection module. The detection module can receive the packet count information from each device and can compare it to the previously received packet count information of the same flow from the same device. Thereby, packet loss can be determined.

Although there is only one network device 100 along the path between the ingress node 300 and the egress node 500, there can however be multiple instance of such network device 100 along multiple nodes of the path.

In other words, the present invention provides a counter update procedure, according to which each network node 100 updates the counter of each traffic flow. It is however also possible that an ingress node or an egress node implements this update procedure. For each packet that traverses a traffic flow and belongs to a flow that is under measurement, the corresponding counter is incremented.

To classify packets into a traffic flow, the present invention also implements a classification method. A flow consists of a set of packets with common characteristics, such as source and destination IP addresses, ports, or protocols. The present invention also implements a classification method that determines which traffic flows are currently being measured (maybe a subset of existing flows in the network) .

By implementing the solution as shown in FIG. 9, the current invention provides per-hop loss measurement using single in-band measurement for each traffic flow. Conversely, prior art solutions require the loss measurement procedure to be invoked for each hop along the path in order to provide the same information about the location of dropped packets. The present invention uses an innovative combination of per-hop per-flow counters with existing in-band telemetry approaches (IOAM or In-band Network Telemetry (INT) ) .

FIG. 10 shows a packet 101 with a reliability measurement field 102 (i.e. the “Measurement Data” in FIG. 2) , wherein the reliability measurement field 102 in particular comprises several entries of packet count information 103 (i.e. the entries labelled with “Counter” ) , all of which are obtained at different instance of the network node 100. Each entry comprises an identifier 201, that is, an index number of the counter. In other words, FIG. 10 shows counters pushed into packets.

FIG. 11 shows reliability measurement fields 102 (i.e. “Measurement Data” ) that are pushed by the ingress node. This data may be pushed with a tunnel header (such as VXLAN-GPE) , as shown in the second line in the figure, or can be pushed as an extension to an existing header in the packet, such as an IPv6 extension header, as shown in the third line. The first line shows a regular packet without the reliability measurement field 102.

FIG. 12 shows a method 1200 according to an embodiment of the present invention. The method 1200 is for reliability measurement and comprises a step of obtaining 1201, by a network node 100, a packet 101, wherein the packet 101 relates to a flow being transferred in the network and comprises a reliability measurement field 102. The method 1200 also comprises a step of obtaining 1202, by the network node 100, packet count information 103 of the network node 100, wherein the packet count information 103 represents a number of packets of the flow forwarded by the network node 100. The method 1200 also comprises a step of inserting 1203, by the network node 100, the packet count information 103 of the network node 100 to the reliability measurement field 102. The method 1200 also comprises a step of forwarding 1204, by the network node 100, the packet 101 to a next hop of the forwarding network node 100.

FIG. 13 shows a method 1300 according to an embodiment of the present invention. The method 1300 is for preparing a packet 301 for reliability measurement and comprises a step of obtaining 1301, by a network node 300, the packet 301 from a source node. The method 1300 also comprises a step of adding 1302, by the network node 300, a reliability measurement field 302 to the packet 301, wherein the reliability measurement field 302 comprises initial packet count information 303. The method 1300 also comprises a step of forwarding 1303, by the network node 300, the packet 301 to a network node 300 for reliability measurement.

FIG. 14 shows a method 1400 according to an embodiment of the present invention. The method 1400 is for completing reliability measurement and comprises a step of obtaining 1401, by a network node 500, a packet 501 from a network node 100, wherein the packet 501 comprises a reliability measurement field 502 comprising packet count information 503 of one or more network nodes by which the packet was passed in the network. The method 1400 also comprises a step of removing 1402, by the network node 500, the reliability measurement field 502 from the packet. The method 1400 also comprises a step of providing 1403, by the network node 500, the reliability measurement field 502 to an evaluation node 700. The method 1400 also comprises a step of forwarding 1404, by the network node 500, the packet 501 to a destination node.

FIG. 15 shows a method 1500 according to an embodiment of the present invention. The method 1500 is for reliability measurement of a flow in a network and comprises a step of obtaining 1501, by an evaluation node 700, a first reliability measurement field 701 relating to a first packet and a second reliability measurement field 702 relating to a second packet from an egress network node 500, wherein the first reliability measurement field 701 comprises a first packet count information 703 and wherein the second reliability measurement field 702 comprises a second packet count information 704. The method 1400 also comprises a step of evaluating 1502, by the evaluation node 700, a reliability of the flow, based on the first packet count information 703 and the second packet count information 704.

Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims.

The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

It is expected that during the life of a patent maturing from this application many relevant keys will be developed and the scope of the term key is intended to include all such new technologies a priori.

The terms "comprises" , "comprising" , "includes" , "including" , “having” and their conjugates mean "including but not limited to" . This term encompasses the terms "consisting of" and "consisting essentially of" .

The phrase "consisting essentially of" means that the composition or method may include additional ingredients and/or steps, but only if the additional ingredients and/or steps do not materially alter the basic and novel characteristics of the claimed composition or method.

As used herein, the singular form "a" , "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

The word “exemplary” is used herein to mean “serving as an example, instance or illustration” . Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments.

The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments” . Any particular embodiment of the invention may include a plurality of “optional” features unless such features conflict.

Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

A network node (100) for reliability measurement of a network, wherein the network node (100) is configured to:

- obtain a packet (101) , wherein the packet (101) relates to a flow being transferred in the network and comprises a reliability measurement field (102) ;

- obtain packet count information (103) of the network node (100) , wherein the packet count information (103) represents the number of packets of the flow forwarded by the network node (100) ;

- insert the packet count information (103) of the network node (100) to the reliability measurement field (102) ;

- forward the packet (101) to a next hop of the network node (100) .
The network node (100) according to claim 1, wherein the packet (101) is obtained from a last hop of the network node (100) .
The network node (100) according to claim 1 or 2, wherein the obtained packet count information (103) further comprises a first identifier (201) , wherein the first identifier (201) is obtained by increasing by 1 an identifier of the packet count information of the network node of the last hop.
The network node (100) according to any one of the preceding claims, further configured to provide the obtained packet count information (103) to an evaluation node.
A network node (300) for preparing a packet (301) for reliability measurement of the network, wherein the network node (300) is configured to:

- obtain the packet (301) from a source node;

- add a reliability measurement field (302) to the packet (301) , wherein the reliability measurement field (302) comprises initial packet count information (303) ; and

- forward the packet (301) to a network node (100) for reliability measurement.
The network node (300) according to claim 5, wherein the initial packet count information (303) further comprises a second identifier (401) , wherein the second identifier (401) specifies an order number of the network node (300) for preparing a packet for reliability measurement among hops in the network.
A network node (500) for completing reliability measurement of a network, wherein the network node (500) is configured to:

- obtain a packet (501) from a network node (100) for reliability measurement, wherein the packet (501) comprises a reliability measurement field (502) comprising packet count information (503) of one or more network nodes by which the packet was passed in the network;

- remove the reliability measurement field (502) from the packet;

- provide the reliability measurement field (502) to an evaluation node (700) , and

- forward the packet (501) to a destination node.
The network node (500) according to claim 7, wherein the obtained packet count information (503) further comprises an identifier (601) of the obtained packet count information (503) .
An evaluation node (700) for reliability measurement of a flow in a network, wherein the evaluation node (700) is configured to:

- obtain a first reliability measurement field (701) relating to a first packet and a second reliability measurement field (702) relating to a second packet from an egress network node (500) , wherein the first reliability measurement field (701) comprises a first packet count information (703) and wherein the second reliability measurement field (702) comprises a second packet count information (704) ; and

- evaluate a reliability of the flow, based on the first packet count information (703) and the second packet count information (704) .
The evaluation node (700) according to claim 9, wherein an identifier (801) of the second packet count information (704) is identical to an identifier (802) to the first packet count information (703) and wherein the evaluation node (700) is further configured to detect packet loss based on a difference of a count value of the second packet count information (704) and a count value of the first packet count information (703) .
A method (1200) for reliability measurement, wherein the method (1200) comprises:

- obtaining (1201) , by a network node (100) , a packet (101) , wherein the packet (101) relates to a flow being transferred in the network and comprises a reliability measurement field (102) ;

- obtaining (1202) , by the network node (100) , packet count information (103) of the network node (100) , wherein the packet count information (103) represents the number of packets of the flow forwarded by the network node (100) ;

- inserting (1203) , by the network node (100) , the packet count information (103) of the network node (100) to the reliability measurement field (102) ;

- forwarding (1204) , by the network node (100) , the packet (101) to a next hop of the forwarding network node (100) .
A method (1300) for preparing a packet (301) for reliability measurement, wherein the method (1300) comprises:

- obtaining (1301) , by a network node (300) , the packet (301) from a source node;

- adding (1302) , by the network node (300) , a reliability measurement field (302) to the packet (301) , wherein the reliability measurement field (302) comprises initial packet count information (303) ; and

- forwarding (1303) , by the network node (300) , the packet (301) to a network node (300) for reliability measurement.
A method (1400) for completing reliability measurement, wherein the method (1400) comprises:

- obtaining (1401) , by a network node (500) , a packet (501) from a network node (100) , wherein the packet (501) comprises a reliability measurement field (502) comprising packet count information (503) of one or more network nodes by which the packet was passed in the network;

- removing (1402) , by the network node (500) , the reliability measurement field (502) from the packet;

- providing (1403) , by the network node (500) , the reliability measurement field (502) to an evaluation node (700) ; and

- forwarding (1404) , by the network node (500) , the packet (501) to a destination node.
A method (1500) for reliability measurement of a flow in a network, wherein the method (1500) comprises:

- obtaining (1501) , by an evaluation node (700) , a first reliability measurement field (701) relating to a first packet and a second reliability measurement field (702) relating to a second packet from an egress network node (500) , wherein the first reliability measurement field (701) comprises a first packet count information (703) and wherein the second reliability measurement field (702) comprises a second packet count information (704) ; and

- evaluating (1502) , by the evaluation node (700) , a reliability of the flow, based on the first packet count information (703) and the second packet count information (704) .
A computer program product comprising computer readable code instructions which, when run in a computer will cause the computer to perform the method according to any one of claims 11-14.
A computer readable storage medium comprising computer program code instructions, being executable by a computer, for performing a method according to any one of claims 11-14 when the computer program code instructions runs on a computer.