Title of Invention	METHOD OF GLOBAL TRAFFIC POLICING AND PACKET TRAFFIC TRANSPORT APPARATUS
Abstract	An apparatus and a method are described in which a flow of packets is distributed in several separate flows over several links (12) forming a logically aggregated link (11). The flow outgoing from each physical link is sent to its own policer (18) which applies to said flow a traffic policing algorithm with the policers being interconnected to exchange algorithm control parameter modification information to fit them in among the various policers while allowing for the control parameters of the others so that a distributed policer (15) is realized.

Title of Invention

METHOD OF GLOBAL TRAFFIC POLICING AND PACKET TRAFFIC TRANSPORT APPARATUS

Abstract

An apparatus and a method are described in which a flow of packets is distributed in several separate flows over several links (12) forming a logically aggregated link (11). The flow outgoing from each physical link is sent to its own policer (18) which applies to said flow a traffic policing algorithm with the policers being interconnected to exchange algorithm control parameter modification information to fit them in among the various policers while allowing for the control parameters of the others so that a distributed policer (15) is realized.

Full Text	FORM 2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See section 10, rule 13) " TRAFFIC POLICING " ERICSSON AB, S-16480 Stockholm, Sweden. The following specification particularly describes the invention and the manner in which it is to be performed. WO 2007/060191 PCT/EP2006/068798 This invention relates to a packet transport method and apparatus for traffic policing. 5 Telecommunication networks carrying multiple different services, such as triple-play traffic, are necessarily required to support services with different requirements. 10 A network whose nodes have traffic control functionality allows sizing of transport services with a certain flow granularity. For this purpose a service contract (or Service Level Agreement (SLA)) is established between the users of the traffic and the network operator who provides 15 the transport service. One of the important aspects of the contract is the specification of the make up of the traffic that will benefit from the service and how the service itself is to be performed; this is the traffic contract (or Service Level Specification (SLS)). The traffic contract 20 provides a description of the traffic that will be served (or 'traffic description' ) and a description of the transport service (or Quality of Service (QoS) specification). 25 The purpose of the traffic contract in the preliminary step is to establish whether the service requirement can be met by the network, while in the delivery step that of operating an application of the served traffic contract (or 'traffic policing') depending on the description given by - 2 - WO 2007/060191 PCT/EP2006/068798 the user. Depending on the traffic contract, as long as the traffic sent in the network conforms to the description given, it has the right to the level of service required and granted. 5 Traffic policing is usually configured on the input interfaces of a network and allows evaluation of the conformity of the traffic received over an interface and partitioning of a network into multiple levels of priority 10 or Class of Service (CoS). In addition, traffic policing performs measurement of the traffic profile (or 'metering') and possibly marking of the traffic packets so that the subsequent dropping of the traffic not conforming .can be done on the basis of this marking. 15 In the most common traffic policing configurations, conforming traffic is transmitted and excess traffic is sent with decreasing priority or dropped. Users can change these configuration options to satisfy their network 20 necessities. Traffic transport utilizing logically aggregated links is well known. For example, standard IEEE802.3-2002 defines a functionality termed Link Aggregation (LA) where a 25 logically aggregated link is made up of a number of physical links (for example, over Ethernet network links) . This functionality can be used for a number of reasons, the most important of which are a functionality simplified from the viewpoint of the upper layers, logical bandwidth - 3- WO 2007/060191 PCT/EP2006/068798 increase and a greater traffic protection capability. More generally, link aggregation falls within the use of individual logical traffic entities, that is to say, the 5 use of entities which for the upper layers of the network appear as a single entity, but which in reality use different physical ports (generically M in number) which reside on different traffic cards (generically N in number) which can also be supplied on different systems not even 10 necessarily located in the same site. in the prior art under these conditions traffic policing is performed on the individual traffic cards. This has been found to be unsatisfactory, especially when it is desired to 15 observe an established QoS and/or utilize protection functionality on logically aggregated links. The general purpose of this invention is to remedy the above-mentioned shortcomings by making available a packet 20 transport method and apparatus with adaptive traffic policing more aware of the QoS and allowing realizing protection over logically aggregated links in an effective manner. 25 In view of this purpose it was sought to provide in accordance with this invention a method for application of global traffic policing for a flow of packets distributed in several separate flows over several links making up a logically aggregated link in which each separate flow is WO 2007/060191 PCT/EP2006/068798 processed after classification by a policer of its own which applies to said flow a traffic policing algorithm exchanging information with the other policers in such a manner that the control parameters of the algorithm fit in 5 among the various policers while allowing for the control parameters of the others. Again in view of said purpose, it was sought to realized a traffic packet transport scheme in which a flow of packets 10 is distributed in several separate flows over several links that form a logically aggregated link and in which the outgoing flow from each physical link is sent to a policer of its own that processes said flow with a traffic policing algorithm in accordance with this invention. 15 To clarify the explanation of the innovative principles of this invention and its advantages compared with the prior art there is described below with the aid of the annexed drawings a possible embodiment thereof by way of non-20 limiting example applying said principles. In the drawings: FIG 1 shows diagrammatically a point of arrival in a node of a logically aggregated link, 25 FIG 2 shows a functional scheme of the node of FIG 1, and FIG 3 shows a graph of the recalculation time of a possible policing algorithm. - 5- WO 2007/060191 PCT/EP2006/068798 5 With reference to the figures, FIG 1 shows a reference scheme 10 of this invention. This scheme shows a logically aggregated link 11 (coming from the left-hand side of the figure), with the traffic being carried by the link needing 5 to be classified and subjected to traffic policing. The logical link is made up of a plurality of mutually aggregated links 12 and connected to different physical ports which belong to different traffic cards 13 grouped in the more general case on different systems (in the example 10 two systems designated by A and B). In accordance with one aspect of this invention it is wished to provide a classifier 14 and a policer 15 on the flow arriving from the logically aggregated link. In accordance 15 with the principles of this invention it is desired that there be awareness of the QoS and protection mechanisms aware of the QoS on the logically aggregated link. There must therefore be provided a traffic policing 20 function referred to the aggregated link 11 as a whole. But in reality each of the physical links forming the aggregated link arrives at its own separate interface port on a different card and it is therefore not possible to really realize a policer dealing with the logically 25 aggregated link as a whole. FIG 2 shows the functional scheme applying the principles of this invention to obtain a distributed traffic policing on the cards. In accordance with this invention, the - 6- WO 2007/060191 PCT/EP2006/068798 traffic policing is performed by the network processors on different cards. Each of the input links 12 reaches its respective interface 16 and the flows are then sent to corresponding policers 18 after being appropriately 5 classified by means of classifiers 17. The policers do not apply only rules based on local data but exchange information with each other in order to realize a self-adapting distributed policer as a whole. 10 This distributed policer (made up of all the policers 18 with the appropriate information exchange connections 19) allows having a traffic policing that behaves like a single entity while adjusting parameters and behaviour depending on actual conditions (class of services, failure 15 conditions, number of physical gates in the aggregated link, number of different cards et cetera). FIG 2 shows for the sake of simplicity two input flows 12 and. two policers and reference is made below to this 20 situation. But it is clear from the description given below of an application example of this invention how to apply this invention to a larger number of flows each with its own policer with information exchanges for realization of the distributed policer. 25 The two policers 18 are distinguished below by reference letters a and b. The_ policing algorithm selected is for example the known - 7- WO 2007/060191 PCT/EP2006/068798 Two Rate Three Color Marker. This is described by Internet RFC4115, available from http://www.ietf.org/rfc.html. In such a system, two leaky buckets are simulated. One bucket fills with "tokens" at a "committed information rate" (CIR) 5 and the other at an "excess information rate" (EIR) . The buckets each hold a limited number of tokens; in the case of the CIR bucket, this is the "committed burst size" (CBS) and for the EIR bucket the "excess burst size" limit. The buckets start full (i.e. with CBS/EBS tokens) but cannot 10 hold more than their limits; no further tokens will be added over the relevant limit. Each of the EIR, CIR, EBS and CBS can be set for a given flow as desired. Every time a packet is received, the size of the packet is 15 determined and compared against the number of tokens in the buckets. In one implementation, if the packet size in bytes B is less than the number of tokens in the CIR bucket, then the packet is labelled green and B tokens are taken from the CIR bucket. If not, then B is compared to the number of 20 tokens in the EIR bucket; if B is less than this number, the packet is labelled yellow and B tokens are taken from the EIR bucket. If neither bucket has sufficient tokens, then the packet is labelled red. Green packets are generally considered to comply with the user's bandwidth level, whilst 25 yellow and red indicate increasing contravention; packets labelled such may be subject to delay or being dropped. In the general case considered, the traffic parameters associated with the policer and derived from the SLS are WO 2007/060191 PCT/EP2006/068798 indicated here by pl=CIR, p2=EIR, 8l=CBS, 82=EBS. In accordance with this algorithm, a flow of packets is measured and the various packets are marked green, yellow or red depending on whether they conform or not to the 5 bandwidth profile established by the SLS. However, in the case of a logical link, the flow is divided over the various aggregated physical links and the packets should therefore be marked in accordance with said rule while allowing for the flows over the various physical links. 10 The recalculation time of the algorithm is shown in FIG 3. The measured values for each integration time T are the following: MIRa=Mean Information Rate classified by the classifier 'a' 15 MIRb=Mean Information Rate classified by the classifier 'b'. By exchange of the information, weights Wa and Wb are calculated and defined thereby as: Wa=MIRa/(MIRa+MIRb) 20 Wb=MIRb/(MIRa+MIRb). For each policer there are the conditions that: δla≥MTU_size; δ2a≥MTU_size δlb≥MTU_size; δ2b≥MTU_size 25 where MTU size is the Maximum Transfer Unit Size. In the algorithm for exchange ■ of information between policers, various behaviours can be held. If a conservative initial approach towards the equipment is preferred (that WO 2007/060191 PCT/EP2006/068798 10 20 is to say, to save resources at the expense of maximum performance) it will be defined as initial parameters of the policers: v policer policer and the updating of the parameters after each integration time will be: policer 'a': pla=plxWa; p2a=p2xWa; policer 'b': plb=plxWb; p2b=p2xWb; But if an initial approach that wastes equipment but respects in any case the client's requirements, the following will be defined as initial parameters of the policers: policer 'a': pla=pl; p2a=p2; policer 'b': plb=pl; p2b=p2; and the updating of the parameters after each integration time will be: policer 'a': pla=plxWa; p2a=p2xWa; policer 'b': plb=plxWb; p2b=p2xWb; The whole can be generalized for N policers as follows. The weight Wn for the nth policer will be: indicating with MIRn the MIR measured at each integration time for the nth policer (flow) and the summation being the sum of the MIR measured at each integration time for all WO 2007/060191 PCT/EP2006/068798 the policers. In the conservative approach, for the nth policer the initial parameters of pi, p2, 81 and 52 will be pln=pl/N, 5 (that is to say, equally distributed among the policers) while the updating of the parameters after each integration time will be 10 In the approach regarding the client in any case, for the nth policer the initial parameters of p1, p2, δ1 and δ2 will be pln=pl, p2n=p2, S2n=S2 and 82r=82, while the updating of the parameters after each integration time will be plr=plxWn, p2n=p2xWn, 15 It is now clear that the preset purposes have been achieved. Basically, information is exchanged between the policers so that the control parameters for the algorithm that manages the local traffic policing of each policer 20 fits in among the various policers while allowing for the control parameters of the other policers. The information exchange mechanism among policers is described below. 25 After each integration period T (possibly reduced because of an event, as may be seen in FIG 3) each policer sends to all the other policers involved in the aggregation a message containing its own MIRn. The integration period T WO 2007/060191 PCT/EP2006/068798 must be as short as possible but long enough to allow sending and receiving of all the messages between one period and the next. In the case where a policer does not receive within the integration period the MIRn figure of 5 one or more of the other policers involved in the aggregation, it will consider these values equal to zero (this approach, given as an example, is conservative; other approaches can be defined). The transmission of electronic messages between the policers uses control channels 10 designed purposely and realizable either inside one apparatus or between different apparatus, channels that are not subject to further definition within the scope of the patent right claimed here. 15 Said scheme adjusts to various policing algorithms as for example the known Two Rate Three Color Marker as defined by the Internet Engineering Task Force (IETF) , in which case the traffic parameters become pl=PIR (Peak Information Rate), p2=CIR (Committed Information Rate), 5l=PBS (Peak 20 Burst Size), 52=CBS (Committed Burst Size), or to the algorithm as defined by the MEF (Metro Ethernet Forum), in which case the traffic parameters become pl=CIR, p2=EIR (Excess Information Rate) , and 5l=CBS, 82=EBS (Excess Burst Size). 25 In this manner, the traffic policing function, which is performed by the network processors on different cards, behaves like a single entity, satisfying through information exchange in the algorithm the need to adjust -12.- WO 2007/060191 PCT/EP2006/068798 parameters and behaviour depending on the real conditions (class of services., failure conditions, number of physical gates in the aggregated link, number of different cards et cetera). There is thus awareness of the QoS and protection mechanisms aware of the QoS on the logically aggregated link. Naturally the above description of an embodiment applying the innovative principles of this invention is given by way of non-limiting example of said principles within the scope of the exclusive right claimed here. For example, as mentioned above, from the example given, application of this invention to any number of flows and policers is immediate. WO 2007/060191 PCT/EP2006/068798 We CLAIM: 1. Method for application of global traffic policing to a flow of packets distributed in several separate flows on several links maKing up a logically aggregated link in which each separate flow is processed after classification toy a policer of "its own "which applies to said, flow a traffic policing algorithm exchanging information with the other policers in such a manner that the control parameters of the algorithm fit in among the various policers while allowing for the control parameters of the others. 2. Method in accordance with claim 1 in which the information exchanged by the policers includes at least on of the overall data rate through a given policer and the data rate for a given class of service through a given policer. 3. Method in accordance with claim 1 in which the policing algorithm is the Two Rate Three Color Marker. 4. Method in accordance with claim 1 in which, for information exchange, at each integration time T each policer sends to all the other policers involved in the aggregation a message containing its own MIRn equal to the Mean Information Rate measured at each integration time. 5. Method in accordance with claim 4 in which if a policer does not receive within the integration period T the figure -14- WO 2007/060191 PCT/EP2006/068798 MIRn of another policer it assigns to said policer MIRn=0. 6. Method in accordance with claim 1 in which for each flow separated by the nth policer of N policers a weight is calculated as follows: with MIRn equal to Mean Information Rate measured at each integration time for the nth policer and the summation being the sum of the MIR measured at each integration time for all the N policers. 7. Method in accordance with claim 6 in which are defined traffic parameters associated with the policers, derived from the SLS, indicated by p1, p2, δ1, δ2 and that are figures to be observed globally for the distributed flow and the initial parameters of the algorithm for each policer are defined as pln=pl/N, p2r=p2/N, δln=δl/N, δ2„=δ2/N and the updating of the parameters after each integration time is pln=plxWn, p2n=p2xWn, δln=δl and δ2n=δ2 . 8. Method in accordance with claim 6 in v/hich are defined traffic parameters associated with the policers, derived from the SLS, indicated by p1, p2, δ1, δ2 and that are figures to be observed globally for the distributed flow and the initial parameter of the algorithm for each policer are defined as pln=pl, p2n=p2, δln=δl, δ2n=82 and the updating of the parameters after each integration time is -15- WO 2007/060191 PCT/EP2006/068798 pln=plxWn, p2n=p2xWn, δln=δl and δ2n=δ2. 9. Method in accordance with claims 7 or 8 in which the figures to be observed globally for the distributed flow are pl=Peak Information Rate, p2=Committed Information Rate, 8l=Peak Burst Size, 82=Committed Burst Size. 10. Method in accordance with claims 7 or 8 in which the figures to be observed globally for the distributed flow are pl=Committed Information Rate, p2=Excess Information Rate, 8l=Committed Burst Size, 82=Excess Burst Size. 11. Packet traffic transport apparatus comprising a logically aggregated link in which a flow of packets is distributed in several separate flows over several physical links that make up the logically aggregated link, ' in use, and a policer for each of the separate flows in which the apparatus is arranged such that, in use, the flow outgoing from each physical link is sent the relevant policer which processes said flow with a traffic policing algorithm having control parameters with the policers being interconnected with each other so as to, in use, exchange information so as to each modify their relevant traffic policing algorithm control parameters dependent upon the information received from the other policers. 12. Apparatus in accordance with claim 11 in which the information exchanged in use by the policers includes at least on of the overall data rate through a given policer - 16 - WO 2007/060191 PCT/EP2006/068798 and the data rate for a given class of service through a given policer. 13. Apparatus in accordance with claim 11 or claim 12 characterized in that for exchange of information, at each integration T each policer sends to all the other policers involved in the aggregation a message containing its own MIRn equal to the Mean Information Rate measured at each integration time. 14. Apparatus in accordance with claim 13 characterized in that if a policer does not receive within the integration period T the figure MIRn of another policer it assigns to said policer MIRn=0. 15. Apparatus in accordance with any of claims 11 to 14 characterized in that for each separate flow incoming to the nth policer a weight is calculated as follows: with MIRn equal to Mean Information Rate measured at each integration time for the nth policer and the summation being the sum of the MIR measured at each integration time for all the N policers. 16. Apparatus in accordance with claim 15 characterized in that traffic parameters associated "with the policers are defined, derived from the SLS, indicated by p1, p2, δ1, δ2 WO 2007/060191 PCT/EP2006/068798 and that they are figures to be observed globally for the distributed flow and the initial parameters of the algorithm for each policer are defined as pln=pl/N, p2n=p2/N, δln=δl/N, δ2n=δ2/N, and updating of the parameters after each integration time is pln=plxWn, p2n=p2xWn, δln=δl and δ2n=δ2. 17. Apparatus in accordance with claim 15 characterized in that traffic parameters associated with the policers are defined, derived from the SLS, indicated by p1, p2, 51, 82 and that they are figures to be observed globally for the distributed flow and the initial parameters of the algorithm for each policer are defined as pln=pl, p2,-=p2, δln=δl, δ2n=δ2, and updating of the parameter after each integration time is pln=plxWn, p2n=p2xWn, δln=δl and δ2n=δ2. 18. Apparatus in accordance with any of claims 11 to 17 characterized in that the policing algorithm applied in the policer is the Two Rate Three Color Marker. 19. Apparatus in accordance with claims 16 or 17 characterized in that the figures to be observed globally for the distributed flow are pl=Peak Information Rate, p2=Committed Information Rate, 8l=Peak Burst Size, 82=Committed Burst Size. 20. Apparatus in accordance with claims 16 or 17 characterized in that the figures to be observed globally for the distributed flow are pl=Committed Information Rate, WO 2007/060191 PCT/EP2006/068798 18 p2=Excess Information. Rate, 8l=Committed Burst Size, 52=Excess Burst Size. 21. Apparatus in accordance with any of claims 11 to 21 characterized in that between incoming flow and policer there is a packet classifier. 22. Apparatus in accordance with any of claims 11 to 21 characterized in that the policers are realized on separate cards each with incoming flow of a physical link. 23. Apparatus in accordance with claim 22 characterized in that the cards are fitted out on distinct network equipment that can also be located in physically remote nodes. Dated this 21st day of May 2008 (G.DEEPAK SR1NIWAS) Of K & S PARTNERS ATTORNEY FOR THE APPLICANTS 19

Full Text

FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)

"

TRAFFIC POLICING

"

ERICSSON AB, S-16480 Stockholm, Sweden.
The following specification particularly describes the invention and the manner in which it is to be performed.

WO 2007/060191

PCT/EP2006/068798

This invention relates to a packet transport method and apparatus for traffic policing. 5
Telecommunication networks carrying multiple different services, such as triple-play traffic, are necessarily required to support services with different requirements.
10 A network whose nodes have traffic control functionality allows sizing of transport services with a certain flow granularity. For this purpose a service contract (or Service Level Agreement (SLA)) is established between the users of the traffic and the network operator who provides
15 the transport service. One of the important aspects of the contract is the specification of the make up of the traffic that will benefit from the service and how the service itself is to be performed; this is the traffic contract (or Service Level Specification (SLS)). The traffic contract
20 provides a description of the traffic that will be served (or 'traffic description' ) and a description of the transport service (or Quality of Service (QoS) specification).
25 The purpose of the traffic contract in the preliminary step is to establish whether the service requirement can be met by the network, while in the delivery step that of operating an application of the served traffic contract (or 'traffic policing') depending on the description given by
- 2 -

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the user. Depending on the traffic contract, as long as the traffic sent in the network conforms to the description given, it has the right to the level of service required and granted. 5
Traffic policing is usually configured on the input interfaces of a network and allows evaluation of the conformity of the traffic received over an interface and partitioning of a network into multiple levels of priority
10 or Class of Service (CoS). In addition, traffic policing performs measurement of the traffic profile (or 'metering') and possibly marking of the traffic packets so that the subsequent dropping of the traffic not conforming .can be done on the basis of this marking.
15
In the most common traffic policing configurations, conforming traffic is transmitted and excess traffic is sent with decreasing priority or dropped. Users can change these configuration options to satisfy their network
20 necessities.
Traffic transport utilizing logically aggregated links is well known. For example, standard IEEE802.3-2002 defines a functionality termed Link Aggregation (LA) where a 25 logically aggregated link is made up of a number of physical links (for example, over Ethernet network links) . This functionality can be used for a number of reasons, the most important of which are a functionality simplified from the viewpoint of the upper layers, logical bandwidth
- 3-

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increase and a greater traffic protection capability.
More generally, link aggregation falls within the use of individual logical traffic entities, that is to say, the 5 use of entities which for the upper layers of the network appear as a single entity, but which in reality use different physical ports (generically M in number) which reside on different traffic cards (generically N in number) which can also be supplied on different systems not even 10 necessarily located in the same site.
in the prior art under these conditions traffic policing is performed on the individual traffic cards. This has been found to be unsatisfactory, especially when it is desired to 15 observe an established QoS and/or utilize protection functionality on logically aggregated links.
The general purpose of this invention is to remedy the above-mentioned shortcomings by making available a packet 20 transport method and apparatus with adaptive traffic policing more aware of the QoS and allowing realizing protection over logically aggregated links in an effective manner.
25 In view of this purpose it was sought to provide in accordance with this invention a method for application of global traffic policing for a flow of packets distributed in several separate flows over several links making up a logically aggregated link in which each separate flow is

WO 2007/060191

PCT/EP2006/068798

processed after classification by a policer of its own which applies to said flow a traffic policing algorithm exchanging information with the other policers in such a manner that the control parameters of the algorithm fit in 5 among the various policers while allowing for the control parameters of the others.
Again in view of said purpose, it was sought to realized a traffic packet transport scheme in which a flow of packets 10 is distributed in several separate flows over several links that form a logically aggregated link and in which the outgoing flow from each physical link is sent to a policer of its own that processes said flow with a traffic policing algorithm in accordance with this invention. 15
To clarify the explanation of the innovative principles of this invention and its advantages compared with the prior art there is described below with the aid of the annexed drawings a possible embodiment thereof by way of non-20 limiting example applying said principles. In the drawings:
FIG 1 shows diagrammatically a point of arrival in a node of a logically aggregated link,
25 FIG 2 shows a functional scheme of the node of FIG 1, and
FIG 3 shows a graph of the recalculation time of a possible policing algorithm.
- 5-

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5
With reference to the figures, FIG 1 shows a reference scheme 10 of this invention. This scheme shows a logically aggregated link 11 (coming from the left-hand side of the figure), with the traffic being carried by the link needing 5 to be classified and subjected to traffic policing. The logical link is made up of a plurality of mutually aggregated links 12 and connected to different physical ports which belong to different traffic cards 13 grouped in the more general case on different systems (in the example 10 two systems designated by A and B).
In accordance with one aspect of this invention it is wished to provide a classifier 14 and a policer 15 on the flow arriving from the logically aggregated link. In accordance 15 with the principles of this invention it is desired that there be awareness of the QoS and protection mechanisms aware of the QoS on the logically aggregated link.
There must therefore be provided a traffic policing 20 function referred to the aggregated link 11 as a whole. But in reality each of the physical links forming the aggregated link arrives at its own separate interface port on a different card and it is therefore not possible to really realize a policer dealing with the logically 25 aggregated link as a whole.
FIG 2 shows the functional scheme applying the principles of this invention to obtain a distributed traffic policing on the cards. In accordance with this invention, the
- 6-

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traffic policing is performed by the network processors on different cards. Each of the input links 12 reaches its respective interface 16 and the flows are then sent to corresponding policers 18 after being appropriately 5 classified by means of classifiers 17.
The policers do not apply only rules based on local data
but exchange information with each other in order to
realize a self-adapting distributed policer as a whole.
10 This distributed policer (made up of all the policers 18
with the appropriate information exchange connections 19) allows having a traffic policing that behaves like a single entity while adjusting parameters and behaviour depending on actual conditions (class of services, failure 15 conditions, number of physical gates in the aggregated link, number of different cards et cetera).
FIG 2 shows for the sake of simplicity two input flows 12 and. two policers and reference is made below to this
20 situation. But it is clear from the description given below of an application example of this invention how to apply this invention to a larger number of flows each with its own policer with information exchanges for realization of the distributed policer.
25
The two policers 18 are distinguished below by reference letters a and b.
The_ policing algorithm selected is for example the known
- 7-

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Two Rate Three Color Marker. This is described by Internet RFC4115, available from http://www.ietf.org/rfc.html. In such a system, two leaky buckets are simulated. One bucket fills with "tokens" at a "committed information rate" (CIR) 5 and the other at an "excess information rate" (EIR) . The buckets each hold a limited number of tokens; in the case of the CIR bucket, this is the "committed burst size" (CBS) and for the EIR bucket the "excess burst size" limit. The buckets start full (i.e. with CBS/EBS tokens) but cannot 10 hold more than their limits; no further tokens will be added over the relevant limit. Each of the EIR, CIR, EBS and CBS can be set for a given flow as desired.
Every time a packet is received, the size of the packet is
15 determined and compared against the number of tokens in the
buckets. In one implementation, if the packet size in bytes
B is less than the number of tokens in the CIR bucket, then
the packet is labelled green and B tokens are taken from the
CIR bucket. If not, then B is compared to the number of
20 tokens in the EIR bucket; if B is less than this number, the
packet is labelled yellow and B tokens are taken from the
EIR bucket. If neither bucket has sufficient tokens, then
the packet is labelled red. Green packets are generally
considered to comply with the user's bandwidth level, whilst
25 yellow and red indicate increasing contravention; packets
labelled such may be subject to delay or being dropped.
In the general case considered, the traffic parameters associated with the policer and derived from the SLS are

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indicated here by pl=CIR, p2=EIR, 8l=CBS, 82=EBS. In accordance with this algorithm, a flow of packets is measured and the various packets are marked green, yellow or red depending on whether they conform or not to the
5 bandwidth profile established by the SLS. However, in the case of a logical link, the flow is divided over the various aggregated physical links and the packets should therefore be marked in accordance with said rule while allowing for the flows over the various physical links.
10
The recalculation time of the algorithm is shown in FIG 3. The measured values for each integration time T are the following:
MIRa=Mean Information Rate classified by the classifier 'a'
15 MIRb=Mean Information Rate classified by the classifier 'b'.
By exchange of the information, weights Wa and Wb are calculated and defined thereby as: Wa=MIRa/(MIRa+MIRb) 20 Wb=MIRb/(MIRa+MIRb).
For each policer there are the conditions that: δla≥MTU_size; δ2a≥MTU_size δlb≥MTU_size; δ2b≥MTU_size 25 where MTU size is the Maximum Transfer Unit Size.
In the algorithm for exchange ■ of information between policers, various behaviours can be held. If a conservative initial approach towards the equipment is preferred (that

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10

20

is to say, to save resources at the expense of maximum
performance) it will be defined as initial parameters of
the policers: v
policer
policer
and the updating of the parameters after each integration time will be:
policer 'a': pla=plxWa; p2a=p2xWa;
policer 'b': plb=plxWb; p2b=p2xWb;
But if an initial approach that wastes equipment but respects in any case the client's requirements, the following will be defined as initial parameters of the policers:
policer 'a': pla=pl; p2a=p2;
policer 'b': plb=pl; p2b=p2; and the updating of the parameters after each integration time will be:
policer 'a': pla=plxWa; p2a=p2xWa;
policer 'b': plb=plxWb; p2b=p2xWb;
The whole can be generalized for N policers as follows. The weight Wn for the nth policer will be:

indicating with MIRn the MIR measured at each integration time for the nth policer (flow) and the summation being the sum of the MIR measured at each integration time for all

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the policers.
In the conservative approach, for the nth policer the initial parameters of pi, p2, 81 and 52 will be pln=pl/N, 5 (that is to say, equally
distributed among the policers) while the updating of the parameters after each integration time will be

10 In the approach regarding the client in any case, for the nth policer the initial parameters of p1, p2, δ1 and δ2 will be pln=pl, p2n=p2, S2n=S2 and 82r=82, while the updating of the parameters after each integration time will be plr=plxWn, p2n=p2xWn,
15
It is now clear that the preset purposes have been achieved. Basically, information is exchanged between the policers so that the control parameters for the algorithm that manages the local traffic policing of each policer
20 fits in among the various policers while allowing for the control parameters of the other policers.
The information exchange mechanism among policers is described below. 25
After each integration period T (possibly reduced because of an event, as may be seen in FIG 3) each policer sends to all the other policers involved in the aggregation a message containing its own MIRn. The integration period T

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must be as short as possible but long enough to allow sending and receiving of all the messages between one period and the next. In the case where a policer does not receive within the integration period the MIRn figure of
5 one or more of the other policers involved in the aggregation, it will consider these values equal to zero (this approach, given as an example, is conservative; other approaches can be defined). The transmission of electronic messages between the policers uses control channels
10 designed purposely and realizable either inside one apparatus or between different apparatus, channels that are not subject to further definition within the scope of the patent right claimed here.
15 Said scheme adjusts to various policing algorithms as for example the known Two Rate Three Color Marker as defined by the Internet Engineering Task Force (IETF) , in which case the traffic parameters become pl=PIR (Peak Information Rate), p2=CIR (Committed Information Rate), 5l=PBS (Peak
20 Burst Size), 52=CBS (Committed Burst Size), or to the
algorithm as defined by the MEF (Metro Ethernet Forum), in
which case the traffic parameters become pl=CIR, p2=EIR
(Excess Information Rate) , and 5l=CBS, 82=EBS (Excess Burst
Size).
25
In this manner, the traffic policing function, which is performed by the network processors on different cards, behaves like a single entity, satisfying through information exchange in the algorithm the need to adjust
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parameters and behaviour depending on the real conditions (class of services., failure conditions, number of physical gates in the aggregated link, number of different cards et cetera). There is thus awareness of the QoS and protection mechanisms aware of the QoS on the logically aggregated link.
Naturally the above description of an embodiment applying the innovative principles of this invention is given by way of non-limiting example of said principles within the scope of the exclusive right claimed here. For example, as mentioned above, from the example given, application of this invention to any number of flows and policers is immediate.

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We CLAIM:
1. Method for application of global traffic policing to a flow of packets distributed in several separate flows on several links maKing up a logically aggregated link in which each separate flow is processed after classification toy a policer of "its own "which applies to said, flow a traffic policing algorithm exchanging information with the other policers in such a manner that the control parameters of the algorithm fit in among the various policers while allowing for the control parameters of the others.
2. Method in accordance with claim 1 in which the information exchanged by the policers includes at least on of the overall data rate through a given policer and the data rate for a given class of service through a given policer.

3. Method in accordance with claim 1 in which the policing algorithm is the Two Rate Three Color Marker.
4. Method in accordance with claim 1 in which, for information exchange, at each integration time T each policer sends to all the other policers involved in the aggregation a message containing its own MIRn equal to the Mean Information Rate measured at each integration time.
5. Method in accordance with claim 4 in which if a policer does not receive within the integration period T the figure
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MIRn of another policer it assigns to said policer MIRn=0.
6. Method in accordance with claim 1 in which for each flow separated by the nth policer of N policers a weight is calculated as follows:
with MIRn equal to Mean Information Rate measured at each integration time for the nth policer and the summation being the sum of the MIR measured at each integration time for all the N policers.
7. Method in accordance with claim 6 in which are defined traffic parameters associated with the policers, derived from the SLS, indicated by p1, p2, δ1, δ2 and that are figures to be observed globally for the distributed flow and the initial parameters of the algorithm for each policer are defined as pln=pl/N, p2r=p2/N, δln=δl/N, δ2„=δ2/N and the updating of the parameters after each integration time is pln=plxWn, p2n=p2xWn, δln=δl and δ2n=δ2 .
8. Method in accordance with claim 6 in v/hich are defined traffic parameters associated with the policers, derived from the SLS, indicated by p1, p2, δ1, δ2 and that are figures to be observed globally for the distributed flow and the initial parameter of the algorithm for each policer are defined as pln=pl, p2n=p2, δln=δl, δ2n=82 and the updating of the parameters after each integration time is
-15-

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pln=plxWn, p2n=p2xWn, δln=δl and δ2n=δ2.
9. Method in accordance with claims 7 or 8 in which the figures to be observed globally for the distributed flow are pl=Peak Information Rate, p2=Committed Information Rate, 8l=Peak Burst Size, 82=Committed Burst Size.
10. Method in accordance with claims 7 or 8 in which the figures to be observed globally for the distributed flow are pl=Committed Information Rate, p2=Excess Information Rate, 8l=Committed Burst Size, 82=Excess Burst Size.
11. Packet traffic transport apparatus comprising a
logically aggregated link in which a flow of packets is
distributed in several separate flows over several physical
links that make up the logically aggregated link, ' in use,
and a policer for each of the separate flows in which the
apparatus is arranged such that, in use, the flow outgoing
from each physical link is sent the relevant policer which
processes said flow with a traffic policing algorithm
having control parameters with the policers being
interconnected with each other so as to, in use, exchange
information so as to each modify their relevant traffic
policing algorithm control parameters dependent upon the
information received from the other policers.
12. Apparatus in accordance with claim 11 in which the
information exchanged in use by the policers includes at
least on of the overall data rate through a given policer
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and the data rate for a given class of service through a given policer.
13. Apparatus in accordance with claim 11 or claim 12 characterized in that for exchange of information, at each integration T each policer sends to all the other policers involved in the aggregation a message containing its own MIRn equal to the Mean Information Rate measured at each integration time.
14. Apparatus in accordance with claim 13 characterized in that if a policer does not receive within the integration period T the figure MIRn of another policer it assigns to said policer MIRn=0.
15. Apparatus in accordance with any of claims 11 to 14 characterized in that for each separate flow incoming to the nth policer a weight is calculated as follows:

with MIRn equal to Mean Information Rate measured at each integration time for the nth policer and the summation being the sum of the MIR measured at each integration time for all the N policers.
16. Apparatus in accordance with claim 15 characterized in that traffic parameters associated "with the policers are defined, derived from the SLS, indicated by p1, p2, δ1, δ2

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and that they are figures to be observed globally for the distributed flow and the initial parameters of the algorithm for each policer are defined as pln=pl/N, p2n=p2/N, δln=δl/N, δ2n=δ2/N, and updating of the parameters after each integration time is pln=plxWn, p2n=p2xWn, δln=δl and δ2n=δ2.
17. Apparatus in accordance with claim 15 characterized in
that traffic parameters associated with the policers are
defined, derived from the SLS, indicated by p1, p2, 51, 82
and that they are figures to be observed globally for the distributed flow and the initial parameters of the algorithm for each policer are defined as pln=pl, p2,-=p2, δln=δl, δ2n=δ2, and updating of the parameter after each integration time is pln=plxWn, p2n=p2xWn, δln=δl and δ2n=δ2.
18. Apparatus in accordance with any of claims 11 to 17
characterized in that the policing algorithm applied in the
policer is the Two Rate Three Color Marker.
19. Apparatus in accordance with claims 16 or 17
characterized in that the figures to be observed globally
for the distributed flow are pl=Peak Information Rate,
p2=Committed Information Rate, 8l=Peak Burst Size,
82=Committed Burst Size.
20. Apparatus in accordance with claims 16 or 17
characterized in that the figures to be observed globally
for the distributed flow are pl=Committed Information Rate,

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18
p2=Excess Information. Rate, 8l=Committed Burst Size, 52=Excess Burst Size.
21. Apparatus in accordance with any of claims 11 to 21 characterized in that between incoming flow and policer there is a packet classifier.
22. Apparatus in accordance with any of claims 11 to 21 characterized in that the policers are realized on separate cards each with incoming flow of a physical link.
23. Apparatus in accordance with claim 22 characterized in that the cards are fitted out on distinct network equipment that can also be located in physically remote nodes.
Dated this 21st day of May 2008

(G.DEEPAK SR1NIWAS)
Of K & S PARTNERS
ATTORNEY FOR THE APPLICANTS
19

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=GjUj2h5he4JAL0gxesa2eA==&loc=vsnutRQWHdTHa1EUofPtPQ==

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Patent Number

270349

Indian Patent Application Number

1033/MUMNP/2008

PG Journal Number

51/2015

Publication Date

18-Dec-2015

Grant Date

15-Dec-2015

Date of Filing

23-May-2008

Name of Patentee

ERICSSON AB

Applicant Address

S-16480 STOCKHOLM.

Inventors:

#	Inventor's Name	Inventor's Address
1	MARTINOTTI, RICCARDO	VICO DEI GALLICO, 1/B/4, 1-17100, SAVONA, ITALY
2	CORTI, ANDREA	VIA DEGLI OLEANDRI, 10/2, I-17019 VARAZZE, ITALY.
3	FIORONE, RAOUL	VIALE VILLA GAVOTTI, 140/2,I-13155 GENOA, ITALY.
4	MARTINOTTI,RICCARDO	VICO DEI GALLICO,1/B/4,I-17100 SAVONA

PCT International Classification Number

H04L12/56

PCT International Application Number

PCT/EP2006/068798

PCT International Filing date

2006-11-23

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	MI2005A002238	2005-11-23	Italy