throbber
l12)UK Patent Application (19)GB (m2 338 372 (13)A
`
`(43) Date of A Publication 15.12.1999
`
`
`
` Application No 93127391
`(51)
`INT CL6
`H04L 12/56
`
`
`
`(52) UK CL (Edition 0)
`H4K KTK
`
`(56) Documents Cited
`EP 0814632 A2
`
`(58)
`
`Field of Search
`UK CL (Edition P) H4K KTl(
`INT CL5 HML
`ONUNE: WPI
`
`Date of Filing 12.05.1993
`
`
`
`(71) Applicantls)
`Telefonaktiebolaget L M Ericsson
`(Incorporated in Sweden)
`S-126 25, Stockholm, Sweden
`
`(72)
`
`lnventor(s)
`Andras Veres
`Zolta'n Turanyi
`
`
`
`
`(74) Agent and/or Address for Service
`Haseltine Lake & 00
`Imperial House, 15-19 Kingsway, LONDON,
`WCZB SUD, United Kingdom
`
`
`
`
`
`(54) Abstract Title
`Packet-switched networks
`
`(57) A switching node 3 for providing admission control in a network comprises a number of separate priority
`queues 6 for receiving packets having different priority levels. Priority levels 1 to n provide guaranteed delay
`services, priority levels n+1 to m provide guaranteed loss services, and priority level Pm,,1 provides best effort
`service. Measuring means 51 to 5m continually measure the average bit rate entering each priority level buffer
`P1 to Pm, except the lowest Pm.-,. When a request arrives with a kth priority level, the network capacities for
`priority levels £’=k..Pm are calculated. For all choices of E, the measurements oftraffic loads of levels Z and
`higher are taken into account. These capacity requirements are necessary to guarantee the quality of service
`for all flows already admitted to the lower priority queues. These capacities are compared to the network
`capacity, and if there is sufficient capacity, the request is accepted. Otherwise, the request is rejected.
`
`VZL88S8Z85)
`
`
`J|MEASURER
`
`‘ MBASURER
`
`BEST EFFORT b1
`
`
`
`
`
`
`
`PRIORITY
`QUEUES
`
`FIG. 4
`
`51
`MESURER
`
`PRl0RlTY
`
`SCHEDULER
`
`
`
`
`PRIORITY
`CLASSIFIER
`
`
`
`At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.
`
`ERICSSON EXHIBIT 1010
`ERICSSON V. IV
`
`IPR2015—01872
`
`

`
`1/3
`
`CLASS|F|ER
`
`ADM|SSS|ON
`CONTROL
`
`12
`
`
` PACKET
`
`
`SCHEDULER
`
`PACKETS
`
`N QUEUES (SEPARATE
`QUEUE FOR EACH FLOW)
`
`FIG. 1
`PRIOR ART
`
`
`
`DYNAMIC
`QUEUE/MEMORY
`HANDLER
`
`
`
`13
`
`18
`
`15
`
`PACKET
`
`CLASSIFIER
`
`17
`
`SCHEDULER
`
`PACKETS
`
`ADMISSSION
`CONTROL
`
`P333. 2
`
`
`
`PRIOR ART
`
`N QUEUES (SEPARATE
`QUEUE FOR EACH Q08 CLASS)
`
`PACKETS
`
`FLOW SETUP
`SIGNALLING
`MESSAGES
`
`PACKETS
`
`FLOW SETUP
`SIGNALLING
`MESSAGES
`
`

`
`2/3
`
`1
`
`2
`
`2
`
`1
`
`END
`
`SYSTEM
`
`EDGE
`DEVICE
`
`SWITCHING
`ELEMENT
`
`
`
`EDGE
`DEVICE
`
`
`
`END
`SYSTEM
`
`
`
`SWITCHING
`ELEMENT
`
`
`
`FIG. 3
`
`MEASURER
`
`PRIORITY
`CLASSIFIER
`
`
`
`
`
`51
`
`EASURER
`i
`
`\ MEASURER
`
`FIG. 4
`
` PRIORITY
`
`QUEUES
`
`SCHEDULER
`
`PRIORITY
`
`BEST EFFORT b1
`
`

`
`3/3
`
`START
`
`
`
`
`
`RECEIVE A NEW REQUEST TO ADMIT
`FLOW HAVING KTH PRIORITY LEVEL
`
`
`
`CALCULATE REQUIRED CAPACITIES
`
`FOR THE KTH LEVEL AND ALL LOWER
`LEVELS AS WELL
`
`
`
`SUFFICIENT
`CAPACITY FOR ALL
`LEVELS CALCULATED
`ABOVE ?
`
`
`
`
`
`
`
`REJECT
`
`ADMIT REQUEST
`
`
`
`FIG. 5
`
`

`
`-1-
`
`2338372
`
`ARCHITECTURE FOR INTEGRATED SERVICES PACKET—SWITCHED
`
`NETWORKS
`
`TECHNICAL FIELD
`
`The invention relates to a service architecture
`
`for a telecommunication network,
`
`in particular, an
`
`Integrated Services Packet-Switched Networks which
`
`makes it possible to support different applications
`
`requiring different levels of quality-of-service (Qos).
`TECHNICAL BACKGROUND
`
`The current
`
`trend of integrating communication
`
`networks requires the development of network
`
`architectures that are capable of supporting the
`
`diverse range of quality—of-service needs that are
`
`required for a diverse range of different applications.
`
`Applications differ in the traffic they generate and
`
`the level of data loss and delay they can tolerate.
`
`For example, audio data does not require the packet-
`
`error reliability required of data services, but audio
`
`data cannot tolerate excessive delays. Other
`
`applications can be sensitive to both data loss and
`
`delay.
`
`The network architectures under consideration are
`
`based on the packet
`
`(or cell) switching paradigm, for
`
`example Transmission Control Protocol/Internet Protocol
`
`(TCP/IP) or Asynchronous Transfer Mode
`
`(ATM).
`
`The
`
`basic idea behind integrated services packet—switched
`
`networks is that all traffic is carried over the same
`
`physical network but the packets belonging to flows
`
`with different Qos requirements receive different
`
`treatment
`
`in the network.
`
`A flow represents a stream
`
`of packets having a common traffic (e.g. peak rate) and
`
`loss) description, and also having the same
`QoS (e.g.
`source and destination.
`
`This differentiation in treatment is generally
`
`implemented by a switch mechanism that first classifies
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`

`
`-2-
`
`packets arriving at a Switching Node
`
`(SN) according to
`
`their QOS commitment, and then schedules packets for
`
`transmission based on the result of the classification.
`
`Ideally,
`
`the classifier and scheduler in each switching
`
`node should be simple, fast, scalable and cheap.
`
`In order to protect existing commitments,
`
`the
`
`network must be able to refuse any new request. This
`
`is accomplished using Admission Control
`
`(AC) during
`
`which some mechanism (usually distributed) decides
`
`whether the new request can be admitted or not.
`
`Among the several proposed solutions to the
`
`problem,
`
`they can be categorised into two main groups
`
`depending upon whether or not they have what is known
`
`as "per-flow“ scheduling.
`
`Figure 1 shows a known solution based on per-flow
`
`scheduling. This type of system has a scheduling
`
`algorithm which maintains a per-flow state, and the
`
`amount of work to be done depends on the number of the
`
`flows.
`
`A dynamic queue/memory handler 13 assigns a
`
`separate buffer Q1 to Q“ for each flow.
`
`Each different
`
`source provides a descriptor of its traffic in advance,
`
`limiting the amount of load sent into the network.
`
`The
`
`network decides using admission control 12 whether it
`
`should accept a new request. After admission, an edge
`
`device,
`
`(being a function on the boundary of a trusted
`
`region of a service provider which acts as a checking
`
`point towards another service provider or subscriber).
`
`polices the traffic of the source.
`
`A typical example
`
`of the policing used is Weighted Fair Queuing (WFQ) or
`
`10
`
`15
`
`2O
`
`25
`
`30
`
`similar variants.
`
`Solutions which use this form of per-flow
`
`scheduling have the disadvantage of requiring complex
`
`queue handlers and classifying/scheduling hardware.
`
`For each packet,
`
`the classifier 10 must determine the
`
`corresponding buffer Q; to Q“ that the packet should be
`
`

`
`-3-
`
`put into.
`
`The large and variable number of queues
`
`means that the queue handler's function is complex.
`
`When the next packet is to be sent,
`
`the scheduler 14
`
`must select the appropriate buffer to send from.
`
`The
`
`scheduler 14 can also be a bottleneck due to the large
`
`number of queues it must service.
`
`The per—packet
`
`processing cost can be very high and increases with the
`
`number of flows.
`
`In addition,
`
`the algorithms are not
`
`scalable, which means that as the volume and the number
`
`the processing complexity increases
`of flows increases,
`beyond what can be handled.
`I
`
`Figure 2 shows another known solution based on a
`
`system where there is no per-flow scheduling. This
`
`type of solution provides some fixed, predefined QoS
`
`classes.
`
`The scheduling is not based upon the
`
`individual flows but on the QoS class of the packets.
`
`This type of method requires simpler hardware.
`
`A
`
`separate queue Q1 to Q“ is provided for each QoS class.
`
`The packet classifier 15 classifies the incoming
`
`packets into the appropriate Qos queue, Q1 to Q“. This
`
`solution either tries to ensure better service to
`
`premium users, or explicit deterministic guarantees.
`
`Proposed solutions which do not use per-flow
`
`scheduling have one of two limitations. First,
`
`they
`
`are able to provide only very loose Qos guarantees.
`
`In
`
`addition,
`
`the Q03 metric values are not explicitly
`
`defined,
`
`(e.g. differential services architectures).
`
`Secondly,
`
`the provided guarantees are deterministic,
`
`which means that no statistical multiplexing gain can
`
`be exploited. As a result,
`
`the network utilisation is
`
`very low.
`
`The aim of the present invention is to overcome
`
`the disadvantages of the prior art listed above by
`
`providing a service architecture having a simple and
`
`scalable way to guarantee different levels of quality-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`

`
`-4-
`
`of—service in an integrated services packet—switched
`
`network. This is achieved using switching nodes that
`
`combine simple packet scheduling and measurement based
`
`admission control to provide explicit quality-of-
`
`service guarantees.
`
`SUMMARY OF THE INVENTION
`
`According to a first aspect of the present
`
`invention,
`
`there is provided an admission control
`
`method for a switching node of an integrated services
`
`packet—switched network,
`steps of:
`
`the method comprising the
`V
`
`allocating each incoming flow to a respective
`
`selected one of the plurality of priority levels, based
`
`on service guarantees required by said flow;
`
`determining whether,
`
`if the incoming flow is
`
`admitted,
`
`the service guarantees can be met for the
`
`incoming flow and all previously admitted flows; and,
`
`if so,
`
`admitting the incoming flow.
`
`According to another aspect of the invention, a
`
`switching node comprises:
`
`means for allocating each incoming flow to a
`
`respective one of the priority levels, based on service
`
`guarantees required by said flow;
`
`admission control means for determining whether,
`
`if the incoming flow is admitted,
`
`the service
`
`guarantees can be met for the incoming flow and all
`
`previously admitted flows; and,
`
`means for admitting the incoming flow if this is
`
`so.
`
`According to a further aspect of the invention, an
`
`integrated services packet switched network comprises a
`
`plurality of switching nodes, wherein at least one
`
`switching node comprises:
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`

`
`_b_
`
`means for allocating each incoming flow to a
`
`respective one of the priority levels, based on service
`
`guarantees required by said flow;
`
`admission control means for determining whether,
`
`if the incoming flow is admitted,
`
`the service
`
`guarantees can be met for the incoming flow and all
`
`previously admitted flows; and,
`
`means for admitting the incoming flow if this is
`
`so.
`
`10
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`For a better understanding of the present
`
`invention reference will now be made, by way of
`
`example,
`
`to the accompanying drawings,
`
`in which:
`
`Figure 1 shows an admission control system based
`
`on per—flow scheduling according to the prior art,
`
`Figure 2 shows an admission control system having
`
`no per—flow scheduling according to the prior art,
`
`Figure 3 shows a block diagram of the network
`
`entities constituting the service architecture
`
`according to an embodiment of the present
`
`invention,
`
`Figure 4 shows a switching node having admission
`
`control according to the present
`
`invention,
`
`Figure 5 is a flow diagram illustrating the steps
`
`involved in admitting a new call request
`
`in the
`
`admission control method according to the present
`invention.
`
`15
`
`20
`
`25
`
`30
`
`DETAILED_DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
`
`INVENTION
`
`The integrated services packed—switched network of
`
`the preferred embodiment offers three service
`
`categories.
`
`These are:
`
`35
`
`i.
`
`maximum delay guaranteed,
`
`

`
`-5-
`
`ii. maximum guaranteed packet loss, and
`
`iii. best effort.
`
`Within the delay and loss categories there are a
`
`fixed number of services.
`
`For services in the delay
`
`category the network provides different levels of
`
`maximum guaranteed delay (d1, d2,
`
`...) and strict loss
`
`guarantee, while for services in the loss category
`
`different levels of maximum guaranteed loss (ll, 12,
`
`..) are provided, but no explicit delay.
`
`For the best
`
`effort service no guarantees are given at all, but no
`admission control is performed either. This means that
`
`all bandwidth left unused by the other services can be
`
`exploited.
`
`Figure 3 shows the network elements forming the
`
`network architecture of the present
`
`invention.
`
`The
`
`network consists of end systems 1 that are connected to
`
`edge devices 2.
`
`Each end system 1 signals with its
`
`associated edge device to set up and tear down packet
`
`flows, and to generate the traffic for the admitted
`
`10
`
`15
`
`20
`
`flows.
`
`The edge devices are in turn connected to
`
`switching nodes 3.
`
`The purpose of each edge device 2
`
`is to police the traffic of the admitted connections,
`
`and ensure that the service fields in the packet
`
`headers are set to the service class of the connection.
`
`The operation of the network relies on a
`
`signalling protocol which communicates a new request
`
`from the end system to the network and among network
`
`nodes.
`
`The signalling protocol also signals the
`
`acceptance or rejection of a request, and the
`
`termination of the request from the end system.
`
`The
`
`exact protocol
`
`to be used does not
`
`form part of this
`
`invention,
`above.
`
`so long as it meets the criteria set out
`
`In operation, an end system 1 signals a request
`
`25
`
`30
`
`35
`
`

`
`_'7_
`
`for a new flow to an edge device 2.
`
`The signalling
`
`message contains the service descriptor and the traffic
`
`descriptor.
`
`The traffic descriptor may contain a peak
`
`rate or a leaky bucket descriptor, or both.
`
`The edge
`
`device 2 passes the request along the path of the flow
`
`and each switching node 3 makes an admission control
`
`decision locally. Rejection or acceptance of a request
`
`is signalled back to the end system 1.
`
`If the flow was accepted the end system 1 starts
`
`to transmit data to the edge device 2.
`
`The edge device
`
`2 is responsible for identifying the flow which the
`
`packet belongs to.
`
`It checks if the packet conforms to
`
`the flow's traffic descriptor.
`
`If not,
`
`the edge device
`
`2 drops the packet.
`
`If the packet conforms,
`
`the edge
`
`device assigns a priority level to the packet based on
`
`the QoS requirements of the flow.
`
`The priority level
`
`is stored in the packet header (for example,
`
`the TOS
`
`field in IP packets or the VPI/VCI field in ATM cells).
`
`The packet travels along the path to its destination.
`
`In each switching node 3
`
`the packet is sent to the
`
`queue corresponding to the value in the packet header.
`
`Queues are serviced on a strict priority basis,
`
`thereby
`
`conserving the work of the scheduler.
`
`Figure 4 shows a preferred embodiment of a
`
`switching node providing admission control according to
`
`the present invention.
`
`A priority classifier 4 assigns priorities based
`
`on the service request of the flow, which is
`
`communicated in the service descriptor in the
`
`signalling messages. Admitted packets are sent
`
`to a
`
`number of separate priority queues 6 depending upon the
`
`value contained in the packet header.
`
`The services
`
`within the "delay" service category always receive
`
`higher priority than services in the "loss" service
`
`category.
`
`Priority levels 1 to n provide guaranteed
`
`10
`
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`25
`
`3O
`
`35
`
`

`
`-8-
`
`delay services, and priority levels n+1 to m provide
`
`guaranteed loss services. Within each type of
`
`category,
`
`the more stringent services receive higher
`
`priority than less stringent ones.
`
`For example, d1 has a more demanding service
`
`guarantee, and hence a higher priority level,
`
`than d2,
`
`which is higher than d3, and so on. Likewise, within
`
`the loss category, ll has a more demanding service
`
`guarantee, and hence a higher priority,
`
`than l2, which
`
`The best
`has a higher priority than 13, and so on.
`effort service is always assigned the lowest priority
`
`level Pml.
`
`The switching node 3 has means 51 to 5m for
`
`continually measuring the average bit rate entering
`
`each priority level buffer P1 to Pm, except the lowest
`
`Pml. These measurements are used to aid the admission
`
`control algorithm of the present invention.
`
`Figure 5 shows the steps involved in the admission
`
`control method of the present invention.
`
`When a request arrives with the kth priority
`
`level,
`
`the network capacities for priority levels
`
`€=k..Pm are calculated, as shown in step S2.
`
`For all
`
`choices of 9,
`
`the measurements of traffic loads of
`
`levels 2 and higher are taken into account. These
`
`capacity requirements are necessary to guarantee the
`quality of service for all flows already admitted to
`
`the lower priority queues.
`
`These capacities are
`
`compared to the network capacity, step S3, and if there
`is sufficient capacity, step S4,
`the request is
`
`accepted, step S5. Otherwise,
`
`the request in rejected,
`
`step S5.
`
`Thus,
`
`for example,
`
`if there are 10 admitted flows
`
`on each priority P1 to Pmg, and a new request arrives
`
`with the 3rd priority level P3,
`
`then the admission
`
`control means determines if all 31 flows,
`
`those in P1 —
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`
`-9-
`
`P3 and the new flow, can be guaranteed d3 delay using
`
`the whole link capacity.
`
`If the request arrives at the
`
`6th priority level and this is the queue for loss
`
`service with guarantee 12,
`
`then the admission control
`
`means determines if l2 loss can be guaranteed to all of
`
`the 61 flows, namely those in P1 — P6 and the new flow.
`
`This guarantees the quality of service for the kth
`
`level. However, it must be assured that the service
`
`guarantees for the lower priority levels can also be
`
`met. Therefore, as stated above, when a request is
`
`received,
`
`the capacity required for the kth level and
`
`lower levels is calculated.
`
`The new request is
`
`admitted if there is sufficient capacity for the kth
`
`level and all lower priority levels.
`
`In this manner,
`
`the disadvantages of prior art
`
`priority scheduling techniques are avoided,
`
`thereby
`
`preventing the higher priority traffic from severely
`
`blocking the lower priority traffic.
`
`Preferably, admission control for the guaranteed
`
`delay services relies on the following condition being
`met:
`
`"
`1
`90+: Mi+—
`1:1
`dk
`
`-Inns)
`2
`d[(O0+p0dk)2+'e_A (°i+p:dk2] <C
`2
`Lk
`
`‘
`
`where:
`
`p3,o°
`
`the token rate and bucket size of the new flow
`
`k
`
`Ed
`
`pi,ai
`
`AL‘,
`
`assigned priority level of the new flow
`
`saturation probability (should be smaller than
`
`the loss values ll,
`
`l2,
`
`l3,
`
`..., e.g. 10“)
`
`token rate and bucket size of flow i
`
`set of flows belonging to the first k (1...k)
`
`priority levels
`
`C
`
`output link rate
`
`10
`
`15
`
`20
`
`25
`
`30
`
`

`
`-10-
`
`M;
`
`dk
`
`measured average rate of priority level i
`
`delay guarantee of priority level k
`
`Preferably, admission control for the guaranteed
`
`loss services relies on the following two conditions
`
`being met:
`
`Condition 1
`
`
`
`Condition 2
`
`
`
`l0
`
`where:
`
`p0,a0
`
`the token rate and bucket size of the new flow
`
`k
`
`11
`
`pi,ai
`
`AL_*
`
`C
`
`Bk
`
`M;
`
`15
`
`20
`
`assigned priority level of the new flow
`
`saturation probability of guaranteed loss
`service i
`
`token rate and bucket size of flow i
`
`set of flows belonging to the first k (1.
`
`.k)
`
`priority levels
`
`output link rate
`
`buffering capacity at queue k
`
`measured average rate of priority level i
`After flows have been admitted according to the
`
`admission control criteria listed above, a priority
`
`scheduler 7
`
`(shown in Figure 4) services the queues on
`
`a strict priority basis to output the packets from the
`
`25
`
`switching node.
`
`The admission control method described above
`
`overcomes the problems of the prior art in that the
`
`

`
`-11-
`
`admission algorithm is scalable,
`
`ie. does not depend
`
`upon the number of different priority levels, and does
`
`not allow the higher priority traffic to severely block
`
`the lower priority traffic.
`
`The invention has the advantage that the amount of
`
`work required per—packet
`
`in the scheduler is minimal.
`
`The architecture is able to admit more flows than
`
`schemes based on WFQ, and statistical multiplexing can
`
`be done among several traffic classes which increases
`
`the amount of traffic that can be admitted.
`
`When admitting to the kth priority,
`
`the invention
`
`will consider as if all the higher priority traffic
`
`belonged to this class.
`
`In this way, admission control
`
`is not carried out in separate classes, but
`
`in groups
`
`of classes,
`
`thereby increasing the statistical
`
`multiplexing gain.
`
`The scalable, aggregate level
`
`measurements used to monitor the real usage of the
`
`network resources means that network efficiency is
`
`improved.
`
`10
`
`15
`
`ETX98-401
`
`

`
`CLAIMS
`
`1.
`
`An admission control method for a switching
`
`node in an Integrated Services Packet-Switched Network
`
`having a plurality of priority levels based on service
`
`guarantees associated therewith,
`
`the method comprising
`
`the steps of:
`
`allocating each incoming flow to a respective
`
`selected one of the plurality of priority levels, based
`
`on service guarantees required by said flow;
`
`determining whether,
`
`if the incoming flow is
`
`admitted,
`
`the service guarantees can be met for the
`
`incoming flow and all previously admitted flows; and,
`
`if so,
`
`admitting the incoming flow.
`
`2.
`
`A method as claimed in claim 1 wherein the
`
`capacities required for the incoming flow and all the
`
`lower priority flows having guaranteed services are
`
`calculated, and the incoming flow admitted if there is
`
`sufficient network capacity to handle the sum of said
`
`l0
`
`15
`
`20
`
`capacities.
`
`3.
`
`A method as claimed in claim 2 wherein the
`
`step of calculating the required capacity for each flow
`
`involves taking into account the traffic load
`
`measurements for that particular flow and all higher
`
`priority flows.
`
`4.
`
`A method as claimed in any preceding claim
`
`wherein the plurality of priority levels relate to
`
`flows requiring guaranteed delay services,
`
`flows
`
`requiring guaranteed loss services, and,
`
`flows
`
`requiring best effort services.
`
`5.
`
`A method as claimed in claim 4 wherein
`
`priority levels 1 to n are assigned to the flows
`
`requiring guaranteed delay services, priority levels
`
`n+1 to m are assigned to the flows requiring guaranteed
`
`loss services, and, a priority level m+1 is assigned to
`
`25
`
`30
`
`35
`
`

`
`-13-
`
`the flows requiring best effort services.
`
`6.
`
`A method as claimed in any preceding claim
`
`wherein admission control for the guaranteed delay
`
`services relies on the following condition being met:
`
` k
`90 +‘Z:
`5% + i;
`(°i+ 9552
`
`i=1
`
`1:
`
`---"
`
`< C
`
`where:
`
`p0,o0
`
`the token rate and bucket size of the new flow
`
`k
`
`Sd
`
`pi,ai
`
`AL,*
`
`C
`
`Ag
`
`dk
`
`assigned priority level of the new flow
`
`saturation probability (should be smaller than
`
`the loss values 11,
`
`l2,
`
`l3,
`
`..., e.g. 104)
`
`token rate and bucket size of flow i
`
`set of flows belonging to the first k (1...k)
`
`priority levels
`
`output link rate
`
`measured average rate of priority level i
`
`delay guarantee of priority level k
`
`7.
`
`A method as claimed in any preceding claim
`
`wherein admission control for the guaranteed loss
`
`services relies on the following two conditions being
`met:
`
`Condition 1
`
`10
`
`15
`
`20
`
`Condition 2
`
`
`
`

`
`..]_4_
`
`where:
`
`po,ao
`
`the token rate and bucket size of the new flow
`
`k
`
`li
`
`pi,ai
`
`AL_J
`
`C
`
`Eu
`
`M;
`
`assigned priority level of the new flow
`
`saturation probability of guaranteed loss
`service i
`
`token rate and bucket size of flow i
`
`set of flows belonging to the first k (l
`
`..k)
`
`priority levels
`
`output link rate
`
`buffering capacity at queue k
`
`measured average rate of priority level i
`
`8.
`
`A switching node for an Integrated Services
`
`Packet-Switched Network having a plurality of priority
`
`levels based on service guarantees associated
`
`therewith,
`
`the switching node comprising:
`
`means for allocating each incoming flow to a
`
`respective one of the priority levels, based on service
`
`guarantees required by said flow;
`
`admission control means for determining whether,
`
`if the incoming flow is admitted,
`
`the service
`
`guarantees can be met for the incoming flow and all
`
`previously admitted flows; and,
`
`means for admitting the incoming flow if this is
`
`10
`
`15
`
`20
`
`25
`
`so.
`
`9.
`
`A switching node as claimed in claim 8
`
`wherein the capacities required for the incoming flow
`
`and all the lower priority flows having guaranteed
`
`services are calculated, and the incoming flow admitted
`
`if there is sufficient network capacity to handle the
`
`sum of said capacities.
`
`10.
`
`A switching node as claimed in claim 9
`
`wherein the step of calculating the required capacity
`
`for each flow involves taking into account the traffic
`
`load measurements for that particular flow and all
`
`30
`
`35
`
`

`
`-15-
`
`higher priority flows.
`
`11.
`
`A switching node as claimed in any of claims
`
`8 to 10 wherein the plurality of priority levels relate
`
`to flows requiring guaranteed delay services,
`
`flows
`
`requiring guaranteed loss services, and,
`
`flows
`
`requiring best effort services.
`
`12.
`
`A switching node as claimed in claim 11
`
`wherein priority levels 1 to n are assigned to the
`
`flows requiring guaranteed delay services, priority
`
`levels n+1 to m are assigned to the flows requiring
`
`guaranteed loss services, and, a priority level m+1 is
`
`assigned to the flows requiring best effort services.
`
`13.
`wherein:
`
`A switching node as claimed in claim 12
`
`queues 1 to n are provided for storing the
`
`guaranteed delay service data;
`
`queues n+1 to m are provided for storing the
`
`guaranteed loss service data; and
`
`10
`
`15
`
`20
`
`a queue m+1 is provided for storing best—effort
`service data.
`
`14.
`
`A switching node according to any of claims 8
`
`to 13 wherein the admission control means admits the
`
`guaranteed delay services if the following condition
`are met:
`
`k
`
`p0+-Z Ml+
`i=1
`
`
`
`25
`
`30
`
`where:
`
`p0,o0
`
`the token rate and bucket size of the new flow
`
`k
`
`assigned priority level of the new flow
`
`Ed
`
`'
`
`saturation probability (should be smaller than
`
`the loss values 11, 12, 13,
`
`..., e.g. 10*)
`
`pi,0i
`
`token rate and bucket size of flow i
`
`

`
`_l6-
`
`AL_*
`
`set of flows belonging to the first k (l...k)
`
`C
`
`HQ
`
`dk
`
`priority levels
`
`output
`
`link rate
`
`measured average rate of priority level i
`
`delay guarantee of priority level k
`
`15.
`
`A switching node according to any of claims 8
`
`to 13 wherein the
`
`admission control means admits the
`
`guaranteed loss services if the following two
`conditions are met:
`
`10
`
`Condition 1
`
`
`
`Condition 2
`
`
`
`15
`
`20
`
`25
`
`where:
`
`po,0o
`
`the token rate and bucket size of the new flow
`
`k
`
`li
`
`pi,oi
`
`AL_*
`
`C
`
`Bk
`
`HQ
`
`assigned priority level of the new flow
`
`saturation probability of guaranteed loss
`service i
`
`token rate and bucket size of flow i
`
`set of flows belonging to the first k (l...k)
`
`priority levels
`
`output link rate
`
`buffering capacity at queue k
`
`measured average rate of priority level i
`
`' 16.
`
`An Integrated Services Packed-Switched
`
`Network having a plurality of priority levels based on
`
`service guarantees associated therewith,
`
`the network
`
`

`
`-17-
`
`comprising a plurality of switching nodes, wherein at
`
`least one switching node comprises:
`
`means for allocating each incoming flow to a
`
`respective one of the priority levels, based on service
`
`guarantees required by said flow;
`
`admission control means for determining whether,
`
`if the incoming flow is admitted,
`
`the service
`
`guarantees can be met for the incoming flow and all
`
`previously admitted flows; and,
`
`means for admitting the incoming flow if this is
`
`so.
`
`17.
`
`An Integrated Services Packed—Switched
`
`Network as claimed in claim 16 wherein the capacities
`
`required for the incoming flow and all the lower
`
`priority flows having guaranteed services are
`
`calculated, and the incoming flow admitted if there is
`
`sufficient network capacity to handle the sum of said
`
`capacities.
`
`18.
`
`An Integrated Services Packed—Switched
`
`Network as claimed in claim 17 wherein the step of
`
`calculating the required capacity for each flow
`
`involves taking into account
`
`the traffic load
`
`measurements for that particular flow and all higher
`
`priority flows.
`
`19.
`
`An Integrated Services Packed—Switched
`
`Network as claimed in any of claims 16 to 18 wherein
`
`the plurality of priority levels relate to flows
`
`requiring guaranteed delay services,
`
`flows requiring
`
`10
`
`15
`
`2O
`
`25
`
`30
`
`guaranteed loss services, and,
`effort services.
`
`flows requiring best
`
`20.
`
`An Integrated Services Packed—Switched
`
`Network as claimed in claim 19 wherein priority levels
`1 to n are assigned to the flows requiring guaranteed
`
`35
`
`delay services, priority levels n+1 to m are assigned
`
`to the flows requiring guaranteed loss services, and, a
`
`

`
`-18-
`
`priority level m+1 is assigned to the flows requiring
`best effort services.
`
`21.
`
`An Integrated Services Packed—Switched
`
`Network as claimed in claim 20 wherein:
`
`queues 1 to n are provided for storing the
`guaranteed delay service data;
`V
`
`queues n+1 to m are provided for storing the
`
`guaranteed loss service data; and
`
`10
`
`a queue m+1 is provided for storing best-effort
`service data.
`
`22.
`
`An Integrated Services Packed—Switched
`
`Network according to any of claims 16 to 21 wherein the
`
`admission control means admits the guaranteed delay
`
`services if the following condition is met:
`
` < C
`
`15
`
`20
`
`25
`
`30
`
`where:
`
`po,00
`
`the token rate and bucket size of the new flow
`
`k
`
`Ed
`
`pi,ci
`
`AL.k
`
`C
`
`kg
`
`dk
`
`assigned priority level of the new flow
`
`saturation probability (should be smaller than
`the loss values 11,
`l2,
`l3,
`..., e.g. 10*)
`
`token rate and bucket size of flow i
`
`set of flows belonging to the first k (1...k)
`
`priority levels
`
`output link rate
`
`measured average rate of priority level i
`
`delay guarantee of priority level k
`
`23.
`
`An Integrated Services Packed-Switched
`
`Network according to any of claims 16 to 21 wherein the
`
`admission control means admits the guaranteed loss
`
`services if the following two conditions are met:
`
`

`
`Condition 1
`
`-19-
`
`
`
`Condition 2
`
`
`
`where:
`
`po,o0
`
`the token rate and bucket size of the new flow
`
`k
`
`11
`
`pi,ai
`
`AL‘*
`
`C
`
`Bk
`
`M;
`
`assigned priority level of the new flow
`
`saturation probability of guaranteed loss
`service i
`
`token rate and bucket size of flow i
`
`set of flows belonging to the first k (1...k)
`
`priority levels
`
`output link rate
`
`buffering capacity at queue k
`
`measured average rate of priority level i
`
`comprising a plurality of switching nodes, wherein at
`
`least one of the switching nodes comprises: having a
`
`switching node according to any of claims 7 to 13.
`
`24.
`
`An admission control method for a switching
`
`node in an Integrated Services Packet-Switched Network
`
`substantially as hereinbefore described with reference
`
`to, and as shown in, Figures 3
`
`to 5 of the accompanying
`
`drawings.
`
`25.
`
`A switching node for an Integrated Services
`
`Packet—Switched Network substantially as hereinbefore
`
`described with reference to, and as shown in, Figures 3
`
`to 5 of the accompanying drawings.
`
`10
`
`15
`
`20
`
`25
`
`

`
`-20-
`
`26.
`
`An Integrated Services Packet Switched
`
`Network having a switching node substantially as
`
`hereinbefore described with reference to, and as shown
`
`in, Figures 3
`
`to 5 of the accompanying drawings.
`
`

`
`
`
`Oflice
`
`ll
`
`Application No:
`Claims searched:
`
`GB 9812789.7
`All
`
`Examiner:
`Date of search:
`
`A1 Strayton
`17 November 1998
`
`Patents Act 1977
`
`Search Report under Section 17
`
`Databases searched:
`
`UK Patent Office collections, including GB, EP, W0 & US patent specifications, in:
`
`ONLINE: WPI
`
`UK Cl (Ed.P): H4K: KTK
`
`Int Cl (Ed.6): H04L
`
`Other:
`
`Documents considered to be relevant:
`
`
`
`Category Identity of document and relevant passage
`if
`
`
`
`Relfivam
`to claims
`
`(NIPPON T.T.) See esp.:abstract; fig.1
`EP 0 814 632 A2
`
`
`
`
`
`
`
`
` Document indicating lack of novelty or inventive step
`A Dowment indicatig technological background and/or state of the art.
`Y
`Document indicating lack of inventive step if combined
`P Document published on or after the declared priority date but before
`
`with one or more other documents of same category.
`the filing date of this invention.
`
`
`E Patent document published on or afler, but with priority date earlier
`& Member of the same patent family
`titan, the filing date of this application.
`
`
`
`
`
`
`
`An Executive Agency of the Department of Trade and Industry

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