WO2000038380A2 - Connection admission control based on bandwidth and buffer usage - Google Patents
Connection admission control based on bandwidth and buffer usage Download PDFInfo
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- WO2000038380A2 WO2000038380A2 PCT/SE1999/002419 SE9902419W WO0038380A2 WO 2000038380 A2 WO2000038380 A2 WO 2000038380A2 SE 9902419 W SE9902419 W SE 9902419W WO 0038380 A2 WO0038380 A2 WO 0038380A2
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
- H04L12/5602—Bandwidth control in ATM Networks, e.g. leaky bucket
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
- H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
- H04Q11/0478—Provisions for broadband connections
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
- H04L2012/5629—Admission control
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
- H04L2012/5638—Services, e.g. multimedia, GOS, QOS
- H04L2012/5646—Cell characteristics, e.g. loss, delay, jitter, sequence integrity
- H04L2012/5651—Priority, marking, classes
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
- H04L2012/5678—Traffic aspects, e.g. arbitration, load balancing, smoothing, buffer management
- H04L2012/5679—Arbitration or scheduling
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
- H04L2012/5678—Traffic aspects, e.g. arbitration, load balancing, smoothing, buffer management
- H04L2012/5681—Buffer or queue management
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/54—Store-and-forward switching systems
- H04L12/56—Packet switching systems
- H04L12/5601—Transfer mode dependent, e.g. ATM
- H04L2012/5678—Traffic aspects, e.g. arbitration, load balancing, smoothing, buffer management
- H04L2012/5684—Characteristics of traffic flows
Definitions
- the present invention pertains to telecommunications, and particular to connection admission control aspects of telecommunications traffic management.
- connection admission control checks to ensure that resource consumption of new connections will not violate the quality of service (QOS) requirements of new and existing connections before admitting the new connections on the network.
- QOS quality of service
- Relevant resources involved in connection admission control (CAC) are channel numbers, bandwidth, and buffer space.
- connection admission control effective/equivalent bandwidth methods are based on the asymptotic behavior of a tail of a queue length distribution.
- the algorithms of such methods calculate an effective bandwidth based on the traffic descriptor, QOS requirements, and buffer resources.
- the effective bandwidth methods are often restricted to a certain type of traffic sources.
- Some real sources may be closest to the Markov fluid-type model, for instance encoded speech. This type of source needs no further shaping to be suitable for transfer through a network, although it has no maximum burst size.
- packet traffic is typically leaky bucket shaped with a peak rate, a sustainable rate, and a maximum burst size.
- the asymptotic behavior of a queue loaded with leaky bucket traffic differs significantly from the behavior of a queue loaded with Markov traffic.
- the leaky bucket-loaded queue has an upper bound on its length, while the Markov- loaded queue has no upper bound.
- Using the asymptotic Markov-type results on leaky bucket traffic will completely loose the leaky bucket burstiness information.
- Using the leaky bucket results with a Markov source does not work because they rely on the limited burst size.
- connection admission control CAC
- the present invention approximates probability of loss using a log moment generating function and its two partial derivatives of workload on a queue over a time interval.
- the approximation uses four state variables, which depend on the log moment generating function and its two partial derivatives.
- the four state variables are as follows:
- Finding the point (s,t) which optimizes the approximation to the probability of loss with the actual buffer size limit, service, and traffic, in real time is generally not feasible. Instead, the present invention uses a predetermined working point (s,t) and adds some imaginary traffic from a design traffic mix to the actual traffic in order to make the working point the optimizing point for the sum of real and imaginary traffic. This makes it sufficient to keep track of the state variables rather than of whole functions.
- the traffic on all connections is admissable if the four conditions are satisfied.
- the first condition is that q be less than or equal to the QOS log loss requirement.
- the second condition is that B be less than or equal to the limit set by available buffer space and QOS delay requirements.
- the third condition is that m is nonnegative.
- the fourth condition is that the mean input rate of real plus imaginary traffic exceeds the mean service rate by no more than admitted by the QOS loss requirement.
- the algorithm cannot make a determination, and therefore, does not admit the traffic.
- a good working point is picked from a region in the (s,t)- plane that performs best with the design traffic mix. If it is desired to widen the tolerance against deviations from the design mix, such may be possible by choosing a working point that is not optimal for the design traffic mix. If it is desired to handle several design traffic mixes, a good working point can be selected for each design mix, state variables maintained for each working point, and calculate q, B, and m calculated at each working point at connection set-up. If no working point rejects the traffic, and at least one working point admits the traffic, the traffic is deemed admissible.
- the present invention applies, e.g., to a single queue and server. Moreover, the invention can be generalized to multiple queues and servers.
- the present invention has a wide range of applicability, working both on a mixture of encoded speech and leaky bucket shaped traffic as well as other types of traffic.
- the traffic may be of fluid or discrete arrivals type. In examples with known exact answer considered so far the method has admitted between 97% and 100% of what is theoretically admissible. Although more complex than a pure efficient bandwidth method, the invention is implementable in real time.
- Fig. 1 is a graph illustrating causes of underestimating loss.
- Fig. 2 is a graph illustrating bounding of x - B by ke sx
- Fig. 3 is a schematic view illustrating a high-priority queue H and a low-priority queue L served by a single server.
- Fig. 4 is a schematic view illustrating N queues of equal priority served by a single server.
- Fig. 5 is a graph showing a simulation of queue length distributions.
- Fig. 6 is a schematic view of an example of queues with shared buffer and independent servers.
- Fig. 7 is a schematic view of a queueing system in a spatial switch of a wideband
- CDMA telecommunications system CDMA telecommunications system
- Fig. 8 A is a graph of a log moment generating function
- Fig. 8B is a graph of the derivative with respect to s of the log moment generating function of Fig. 8 A
- Fig. 8C is a graph of the derivative with respect to t of the log moment generating function of Fig. 8 A
- Fig. 9A - Fig. 9E are graphs showing ON-OFF periodic arrivals.
- Fig. 10A is a graph showing the log moment generating function
- Fig. 11 A is a graph showing the log moment generating function
- Fig. 12A is a graph showing the log moment generating function
- Fig. 13 A is a graph showing the log moment generating function
- Fig. 14A is a graph showing the log moment generating function
- Fig. 15A and Fig. 15B are graphs showing contours of q, B, and m for traffic cases 1, 10, respectively.
- Fig. 16A - Fig. 16D are graphs showing contours of q, B, and m for traffic cases 2, 3, 4, 5, respectively.
- Fig. 17A - Fig. 17D are graphs showing contours of q, B, and m for traffic cases 6, 7, 8, and 9, respectively.
- Fig. 18A - Fig. 18D are graphs showing contours of q, B, and m for traffic cases 11, 12, 13, and 14, respectively.
- Fig. 19A - Fig. 19D are graphs showing contours of q, B, and m for traffic cases 15, 16, 17, and 18, respectively.
- Fig. 20 is a graph showing contours of q, B, and m for a 19 th one connection traffic case.
- Fig. 21A - Fig. 21D are graphs showing contours of q, B, and m for traffic cases 20, 29, 39, 48, respectively.
- Fig. 22A - Fig. 22D are graphs showing contours of q, B, and m for traffic cases 21 , 22, 40, 41 , respectively.
- Fig. 23 A - Fig. 23D are graphs showing contours of q, B, and m for traffic cases 23, 24, 42, 43, respectively.
- Fig. 24A - Fig. 24D are graphs showing contours of q, B, and m for traffic cases 25, 26, 44, 45, respectively.
- Fig. 25 A - Fig. 25D are graphs showing contours of q, B, and m for traffic cases
- Fig. 26A - Fig. 26D are graphs showing contours of q, B, and m for traffic cases 30, 31, 49, 50, respectively.
- Fig. 27A - Fig. 27D are graphs showing contours of q, B, and m for traffic cases 32, 33, 51, 52, respectively.
- Fig. 28A - Fig. 28D are graphs showing contours of q, B, and m for traffic cases 34, 35, 53, 54, respectively.
- Fig. 29A - Fig. 29D are graphs showing contours of q, B, and m for traffic cases 36, 37, 55, 56, respectively.
- Fig. 30A - Fig. 30B are graphs showing contours of q, B, and m for traffic cases 36, 38, 57, respectively.
- Fig. 31 is a schematic view of an node according to an embodiment of the invention.
- Fig. 32A is a schematic view of an node entity which includes a node main processor.
- Fig. 32B is a schematic view of an node entity which serves as an extension terminal.
- Fig. 33 is a graph showing a probability density function.
- Link Admission Control LAC is part of Connection Admission Control CAC.
- LAC examines whether resources are available for a new connection on a link. Resources are channel numbers, buffer space and bandwidth. The present invention considers LAC with respect to bandwidth and buffer usage only.
- a link may contain several queue-and-server systems, for instance, egress queues in the sending node and ingress queues in the receiving node.
- LAC must check for resources in every such system.
- the present invention illustrates an exemplary system.
- Fig. 31 shows a representative node 20 with which the connection admission control (CAC) technique of the present invention can be employed.
- the particular node 20 which serves as an illustration of the connection admission control (CAC) of the present invention is an Asynchronous Transfer Mode (ATM) node 20 comprising a switch core 24.
- Switch core 24 which has plural switch core ports, four of the switch core ports being shown as switch core ports 26 A - 26D in Fig. 31.
- a node entity 30, also known as a device board, is connected to each of the switch core ports.
- Fig. 31 shows node entity 30A being connected by a bidirectional link 32 A to switch core port 26A; node entity 3 OB being connected by another bidirectional link 32B to switch core port 26B; and so forth. It should be understood that more than four node entities 30 can be, and typically are, connected to corresponding ports 26 of switch core 24, but that only four node entities 30 are shown for sake of simplification.
- Each node entity 30 performs one or more functions and has, among other components hereinafter described, a processor mounted thereon.
- One of the node entities 30, particularly node entity 30A has a node main processor which generally supervises operation of the entire ATM node 20.
- the other node entities 30, such as node entities 30B - 30D have entity processors 50B - 50D, respectively, also known as board processors.
- each of node entities 30B - 30D serve as extension terminals. Having such function, the node entities 30B - 30D are connected by physical lines or links to other ATM nodes.
- node entity 30B is shown as having four physical lines 60B-1 through 60B-4 to other (unillustrated) ATM node(s).
- the other node entities 30B and 30C also have four physical lines extending to other (unillustrated) ATM node(s).
- the ATM node 20 serves to route ATM traffic cells between physical lines 60 which connect ATM node 20 to other ATM nodes.
- ATM traffic cells incoming to ATM node 20 on physical line 60B-1 can be routed by switch core 24 to be outgoing from ATM node 20 on physical line 60C-1.
- the entity processor of each node entity 30 plays a significant role when establishing ATM connections to/from that entity.
- an extension terminal (ET) entity the establishing of an ATM connection between a physical line and another node entity (e.g., another extension terminal or any other type of node entity) is performed by setting up a translation table row (hosted in the ATM line module), one for each direction.
- the translation assigns an internal VP CI and an addressee switch port for each utilized VPI/VCI on the physical link.
- the addressee switch port is used to route each cell to the right switch port (i.e., node entity).
- the translation assigns the VPI/VCI to be used on the physical link for each VPI/VCI used internally between two node entities.
- no hardware e.g., no processors perform any tasks concerning cell transfer.
- any other type of node entity e.g., an entity that terminates an ATM connection
- the principles discussed above apply except for the egress direction in which no external VPI/VCI is assigned. Instead, a termination point (software entity of the processor) is utilized.
- node main processor 40 In order to communicate with the node entities 30, and particularly with the entity processors 50 of the respective node entities 30, certain control paths must be established between node main processor 40 and the entity processors 50 so that the processors can communicate with one another. The communication is performed by cells which are transmitted over the control paths established between node main processor 40 and the various entity processors 50. Establishment of these control paths is understood with reference to U.S. Patent Application SN 09/249,785 filed February 16, 1999, "Establishing Internal Control Paths in ATM Node,” which is incorporated herein by reference.
- Fig. 32A shows an example node entity 30A at which node main processor 40 is situated.
- the node entity 30 of Fig. 32A includes a switch port interface module (SPIM) 30A-1 which is connected by bidirectional link 32A to switch core 24.
- the switch port interface module (SPIM) 30A-1 is connected to bus 30A-2, which is preferably a UTOPIA standard bus.
- the node main processor 40 is connected by bus 30A-2 to switch port interface module (SPIM) 30A-1.
- the switch port interface modules (SPIMs) have queues which are affected by traffic management.
- Fig. 32B shows an example node entity 30 which serves as an extension terminal.
- the node entity 30 of Fig. 32B has switch port interface module (SPIM) 30B-1 and bus 30B-2, with a processor (entity processor 50) being connected to bus 30B-2.
- bus 30B-2 is connected to ATM line module 30B- 3.
- the ATM line module 30B-3 contains VPI/VCI translation tables used for performing the external/internal VPI/VCI and internal/external VPI/VCI translations described above.
- the ATM line module 30B-3 is, in turn, connected to line termination module (LTM) 30-4. It is line termination module (LTM) 30B-4 which is connected to the physical lines 60.
- LTM line termination module
- node entity 30 Examples of the components of a node entity 30 are described, for example, in the following United States Patent Applications (all of which are incorporated herein by reference): U.S. Patent Application SN 08/893,507 for "Augmentation of ATM Cell With Buffering Data"; U.S. Patent Application SN 08/893,677 for " Buffering of Point-to-Point and/or Point-to-Multipoint ATM Cells"; U.S. Patent Application SN 08/893,479 for "VP/VC Look-Up Function"; U.S. Provisional Application Serial No. 60/086,619 for "Asynchronous Transfer Mode Switch.”
- U.S. Patent Application SN 08/893,507 for "Augmentation of ATM Cell With Buffering Data"
- U.S. Patent Application SN 08/893,677 for " Buffering of Point-to-Point and/or Point-to-Multipoint ATM Cells”
- U.S. Patent Application SN 08/893,479 for "VP/VC Look
- connection admission control (CAC) procedures of the present invention In the representative node 20 herein described it is node main processor 40 (see Fig. 31) which performs the connection admission control (CAC) procedures of the present invention.
- CAC connection admission control
- references hereinafter to an algorithm refer to connection admission control (CAC) procedures executed by node main processor 40.
- CAC connection admission control
- CAC connection admission control
- the connection admission control (CAC) procedures of the present invention could be performed for a telecommunications node by a processor located other than on a device board, or by structures other than a processor (e.g., a hardwired circuit).
- the representative node 20 happens to be an ATM-based node, the connection admission control (CAC) techniques of the present invention are not confined to ATM or to any particular type of telecommunications type (e.g., CDMA). Rather, the connection admission control (CAC) techniques of the present invention can be employed in or for any telecommunications node where traffic management is an issue.
- A(t) denotes the amount of work which arrives in the interval [-t, 0) and S(t) the amount served in the same interval. If more work arrived than can be processed, the surplus waits in the queue, if possible.
- A(t) is the amount arriving in [-t,0)
- R is the mean arrival rate (of stationary arrival process)
- S(t) is the amount that can be served in [-t,0)
- C is the mean service rate
- W(t) A(t) - S(t) is the workload in [-t,0)
- B is the buffer size
- f w (x;t) is the probability density of W(t)
- the bound is tightest for the s that minimizes ⁇ w (s;t) - sB - 1 - log s.
- the s that gives the tightest bound must satisfy
- the proof is outlined using a probability shift argument.
- the function f w (x;t)e sx_ " (5;,) is a probability density function, because it is non-negative and its integral over all x is 1.
- a random variable with this probability density has mean c9 c
- B and q in (3) are not the actual buffer size and log loss probability, but the buffer size and log loss probability that would arise if the unused typical arrivals were added to the l o actual arrivals.
- m and B in (3) are linear functions of the derivatives of ⁇ w (s;t).
- q is the sum of a linear and a logarithmic term.
- a CAC algorithm can keep track of c, z, B, and m by adding contributions from 15 new connections and subtracting contributions from connections being cleared.
- the "unused typical arrivals" formulation of the problem has a "single point calculation" advantage. If the real arrivals come from a typical traffic mix, then the mean rate and log moment generating function of A(t)+U(t) do not vary with the real traffic load. This means that a point (s,t) that admits the traffic at the maximum admissible load also admits at all lower loads. If the real traffic deviates from the typical mix the sum of real and imaginary traffic may still be sufficiently similar to the typical mix to allow a single point (s,t) to admit over a range of real traffic mixes and loads.
- V - - ⁇ — ⁇ w (s; t) - - s K t t ) for s, t > 0 and R + U - C ⁇ (R + U)e q
- Equation Block (5) are not the actual buffer size and log loss probability, but the buffer size and log loss probability that would arise if the actual arrivals were increased by the unused bandwidth.
- An admission control algorithm can keep track of B, R, U, and z by adding contributions from new connections and subtracting contributions from connections being cleared.
- Equation Block (5) A drawback of using Equation Block (5) for real-time admission control is that the (s,t)-region admitting the last connection does not always overlap the (s,t)-region admitting the first connection. In (s,t,load)-space the region admitting the loads may look like a "leaning banana". Thus, it is not sufficient just to calculate Equation Block (5) in a single point (s,t).
- B and q in (6) are not the actual buffer size and log loss probability, but the buffer size and log loss probability that would arise if the actual service was reduced by the unused bandwidth.
- Equation Block (6) admits the arrivals at (s,t), then so does Equation Block (5); but the converse is not true. If Equation Block (5) admits the arrivals at (s,t), the Equation Block (6) may admit or be uncertain.
- Equation Block (6) The log loss probability q in Equation Block (6) is the sum of a linear and a logarithm term
- B, R, U, and z are all linear functions of the log moment generating function of the workload W(t).
- An admission control algorithm can keep track of B, R, U, and z by adding contributions from new connections and subtracting contributions from connections being cleared.
- the unused service bandwidth formulation suffers from the same "leaning banana" trouble as does the unused arrival bandwidth formulation.
- the admission control algorithm of the present invention keeps track of four ⁇ state variables R, ⁇ A (s; t), — ⁇ A (s; t), — ⁇ A (s; t) by adding contributions from new connections.
- the algorithm can calculate q, B, and k from these state variables.
- the arrivals multiplier formulation suffers from the same problem as the unused l o bandwidth formulation, that the point (s,t) that admits the last connection at maximum load will in general not admit the first connection.
- a system consisting of two queues, H and L, served by a single server as shown in Fig. 3.
- the server serves queue H whenever that queue is not empty.
- the server serves queue L when queue H is empty and queue L is not.
- Queue H sees the full service of the server.
- Queues H and L together also see the full service of the server.
- Queue L sees what queue H leaves unused.
- the log moment generating function of the service offered to queue L is determined as follows.
- the service offered to queue L is
- Fig. 5 shows distributions of queue lengths.
- the system comprised 21 queues of equal, low, priority served by a single server. Equal traffic load on all queues with exponentially distributed time between bursts, geometrically distributed number of arrivals in a burst, and constant inter-arrival time within a burst. Scheduling according to a snapshot of queue states, queue 0 served first and queue 20 last. In Fig. 5, the lower set of curves shows the length of queue 0, which was served first in the snapshot; the middle set of curves shows the length of queue 20, which was served last in the snapshot; and the top set of curves shows the sum of the lengths of all 21 queues. 4.2.1 Admission control for Single Priority, Single Server, Shared Buffer
- each of the N queues has a buffer of limited size.
- Fig. 6 shows an example illustrating this point.
- queue 2 is unstable and grows beyond all limits, while the sum of workloads on the queues is less than the sum of services. It is postulated that the total buffer needed for queues with independent servers is approximately equal to the need of the longest queue. A motivation is that the queues are independent and a long queue has a small probability, so when one queue is long, the others are likely to be around their mean length which is much smaller.
- Fig. 7 shows a simplified diagram of the queueing system in the spatial switch SPAS (core 24 in Fig. 31) in a wideband CDMA telecommunications system.
- the switch core 24 comprises rows for incoming data and columns for outgoing data. In the crosspoints between rows and columns there are small buffers which are omitted in Fig. 7.
- the space switch interface modules SPIM contain ingress and egress queues towards and from the switch core, respectively.
- the ingress queues in a SPIM are organized as a queue per egress SPIM and ingress priority. The idea is to store incoming cells in ingress queues and transfer them in an ingress priority order towards the switch core when the corresponding crosspoint is free. Ingress queue (i, j, p) is located in SPIM i and carries traffic towards SPIM j on priority level p.
- the ingress queues in a SPIM share a common buffer memory. Ingress queues in different SPIMs do not share a buffer.
- a round-robin mechanism is used to give equal bandwidth to the different ingress queues within the same priority level.
- the switch core has two priority levels. To get a high priority cell through the switch core when a low priority cell blocks the crosspoint, a command is sent as a special management cell called Plus Priority cell. This cell is terminated in the core and any cell in the crosspoint buffer gets its priority increased. In this way, the crosspoint will be emptied within a predetermined time.
- the egress SPIM serves the crosspoints in its column according to a snapshot mechanism.
- the SPIM When the SPIM has processed a previous snapshot it takes a new snapshot of the crosspoint buffer states.
- the SPIM empties the non-empty buffers in the snapshot in increasing number order.
- the egress queues are organized as a queue per egress priority and outgoing branch from the SPIM.
- the idea is to store incoming cells in queues and transfer them in egress priority order.
- the egress queues in a SPIM share a common buffer memory. This memory is separate from the ingress buffer memory.
- This section describes how to use the "unused typical arrivals" results for admission control of the ingress queues.
- Row i and column j in the switch core both limit the service of the ingress queues in SPIM i towards SPIM j.
- the ingress admission control algorithm checks that both of these potential bottlenecks give sufficient service.
- the ingress queues served by a row share a buffer in a SPIM. Hence it suffices to keep track of the total workload per priority level when checking for row service.
- the ingress queues served by a column reside in different SPIMs, and therefore do not share a buffer. Hence one must keep track on workload on individual queues when checking for column service. Queues sharing a buffer in a SPIM do not share column service.
- the ingress admission control algorithm for row service uses the following state variables for some set of points (s;t),
- the ingress admission control algorithm for column service uses the following state variables for some set of points (s;t),
- the typical traffic has the following characteristics for some set of points (s;t),
- m c (p,i,j,s;t) a m (p,i,s;t) C.s + tJ
- the new connection adds the following contributions to the row state variables,
- Az c (p, k, j, s; t) ⁇ a (s; t) - s — ⁇ a (s; t) - a z (p, i, s; t) — ⁇ a (s; t) ds d d d d
- An outgoing link serves its egress queues at a constant rate.
- a problem is the traffic arriving to the egress queues. This traffic has changed by passing through the ingress queues and the switch core. As an approximation, assume that the traffic has not changed. This situation is equivalent to handling ingress queues with row service only, see above.
- the algorithm initializes the state variables c, z, B, and m, as described in Equation Blocks (11)-(12). In order to admit a new connection, the algorithm checks every affected priority level. If all priority levels admit the connection, it is admissible, otherwise not.
- the algorithm checks it over one or more time intervals t. If no t rejects the connection, and some t admits it, the queue admits the connection over the time interval t, otherwise the queue rejects the connection.
- the algorithm checks it over one or more values of s for the given t. If some point (s;t) rejects the connection, the time interval rejects it. If no point (s;t) rejects, and some point (s;t) admits the connection, the time interval t admits it.
- the algorithm increments the state variables c, z, B, and m, as described in equations (13)-(14). It checks the rate condition last in equations (3). If the rate condition is OK, the algorithm calculates q as described in equation (4). It corrects the loss probability for losses on higher priority levels at the same point as described in equation (10). If the corrected loss probability is sufficiently small, and the buffer B is sufficiently small, and the traffic multiplier m is non-negative, and the rate condition is OK, then the queue admits the connection at point (s;t). If the corrected loss probability is negative, then the queue rejects the connection at point (s;t). Otherwise the queue is indecisive at point (s;t).
- the algorithm admits a new connection, it updates all affected c, z, B, and m. If the algorithm rejects a new connection, it reverts to the previous values of all affected c, z, B, and m.
- the algorithm decrements all affected c, z, B, and m by the amounts it added when it admitted the connection.
- the source is ON for T on and OFF for T off .
- the source generates data at the peak rate R — , and in the OFF state, it on generates no data.
- This is an extreme behavior acceptable by a leaky bucket regulator with mean rate limit R, and bucket size RT off .
- the phase of this periodic pattern is uniformly distributed in [0,T).
- Fig. 9A - Fig. 9E are graphs showing ON-OFF periodic arrivals.
- A( ⁇ J+ ⁇ ) is the amount arriving in [ ⁇ ,t+ ⁇ ).
- the phase ⁇ is uniformly distributed in [0, T on + T off ).
- the density function of A is the sum of two delta-impulses and a uniform distribution between them.
- V y w az + bv + c
- Fig.10A is a graph showing the Log moment generating function
- Example 3 Discrete Periodic Arrivals
- the phase ⁇ T is uniformly distributed in [0,T).
- the log moment generating function, its derivatives, and the asymptotic log moment generating functions are the log moment generating function, its derivatives, and the asymptotic log moment generating functions.
- Fig. 11 A is a graph showing the log moment generating function
- the mean interval time is T.
- Each arrival contributes an amount of RT.
- the probability of k arrivals in time t is (e _t/T (t/T) k )/k!.
- the log moment generating function and its derivatives of the arrival process are (as explained in A. Papoulis, "Probability, Random Values, and Stochastic Processes", McGraw-Hill, 1965),
- Fig. 12A is a graph showing the log moment generating function
- Example 5 Markov Fluid Arrival Process
- a source is called a Markov fluid if its time-derivative is a function of a continuous-time Markov chain on a finite state space. Let 1, ..., m be the state space and
- R A diag(R, , ... , R m ) diagonal matrix of arrival rates
- Q A +sR A N(s)D(s)V- 1 (s) where D(s) is a diagonal matrix of eigenvalues of Q A +sR A and V(s) is a matrix of column eigenvectors
- Diagonal eigenvalues and column eigenvectors matrices are
- Fig. 13A is a graph showing the log moment generating function
- the probability density function of the amount of data received in time t is
- Fig.14A is a graph showing the log moment generating function
- This section defines some traffic classes spanning a wide range of bandwidth and burstiness. It uses traffic cases spanning a wide range of link loads to illustrate regions of (s,t) admitting or rejecting a traffic case. Table 2 lists traffic classes.
- Table 3 lists numbers traffic cases with one connection.
- Fig. 15A illustrates the foregoing one connection traffic case 1; Fig. 15B illustrates one connection traffic case 10. Both Fig. 15A and Fig. 15B show contours of q, B, and m, for one connection, average rate lOkbit/s.
- Fig. 16A - Fig. 16D illustrate traffic cases 2, 3, 4, 5, (showing contours of q, B, and m) for one connection, average rate lOkbit/s, average period 10 ms.
- Fig. 16B shows case 3 (discrete periodic);
- Fig. 16D shows case 5 (Poisson).
- Fig. 17A - Fig. 17B illustrate traffic cases 6, 7, 8, 9 (showing contours of q, B, and m) for one connection, average rate lOkbit/s, average period 10 s.
- Fig. 17B shows case 7 (discrete periodic);
- Fig. 17D shows case 9 (Poisson).
- Fig. 18A - Fig. 18D illustrate traffic cases 1 1, 12, 13, 14 (showing contours of q, B, and m) for one connection, average rate lOkbit/s, average period 10 ms.
- Fig. 18B shows case 12 (discrete periodic)
- Fig. 18D shows case 14 ( Poisson).
- Fig. 19A - Fig. 19D illustrate traffic cases 15, 16, 17, 18 (showing contours of q, B, and m) one connection, average rate lOkbit/s, average period 10 s.
- Fig. 19B shows case 16 (discrete periodic);
- Fig. 19D shows case 18 (Poisson).
- Traffic case 16 of Fig. 19B is clearly inadmissible.
- a burst of 1 Gbit arrives instantaneously to a buffer of size 3Mbit, which looses 99.7% of the arriving data.
- the reason for this is that the workload over long periods looks acceptable, while it is unacceptable over short periods (see also Fig. 1).
- the global maximum of q occurs in the first period oft.
- the admitting points found are at local maxima in later periods and thus false solutions.
- Another peculiarity of traffic case 16 is that no working point (s,t) is able to reject the case.
- q and B are far from admissible, while m is close to 0; but m>0 everywhere.
- Table 4 lists numbers traffic cases (cases 20 - 38) with the maximum number of connections from a single traffic class admitted by Equation Block (3).
- Table 5 lists numbers traffic cases (cases 39 - 57) with the minimum number of connections from a single traffic class not admitted by Equation Block (3).
- Fig. 21 A - Fig. 2 ID illustrate traffic cases 20, 29, 39, 48 (again showing contours of Contours of q, B, and m), with maximum admissible and minimum inadmissible numbers of connections, average rate lOkbit/s.
- Fig. 21 A shows case 20 (constant rate, 15000 connections);
- Fig. 21C shows case 39 (constant rate, 15001 connections);
- Fig. 22A - Fig. 22D illustrate traffic cases 21, 22, 40, 41 (again showing contours of q, B, and m) for maximum admissible and minimum inadmissible numbers of connections, average rate lOkbit/s, average period 10 ms.
- Fig. 22B shows case 22 (discrete periodic, 14999 connections);
- Fig. 22D shows case 24 (Poisson, 15000 connections).
- Fig. 22 there is no difference between the ON-OFF periodic and discrete periodic models of approximately the same type of connections. This is because the burst size 100 bit is much smaller than the buffer size 3 Mbit.
- Fig. 23A - Fig. 23D illustrate traffic cases 23, 24, 42, 43 (again showing contours of q, B, and m) for maximum admissible and minimum inadmissible numbers of connections, average rate lOkbit/s, average period 10 ms.
- Fig. 23B shows case 24 (Poisson, 14998 connections);
- Fig. 24D shows case 43 (Poisson, 14999 connections).
- Fig. 24A - Fig. 24D illustrate traffic cases 25, 26, 44, 45 (again showing contours of q, B, and m) for maximum admissible and minimum inadmissible numbers of connections, average rate lOkbit/s, average period 100 s.
- Fig. 24B shows case 26 (discrete periodic, 84 connections);
- Fig. 24D shows case 45 (discrete period, 85 connections).
- Fig. 24 there is a great difference between the ON-OFF periodic and discrete periodic models of approximately the same type of connections.
- Fig. 25A - Fig. 25D illustrate traffic cases 27, 28, 46, 47 (again for contours of q, B, and m) for maximum admissible and minimum inadmissible numbers of connections, average rate lOkbit/s, average period 100 s.
- Fig. 25B shows case 28 (Poisson, 81 connections);
- Fig. 25D shows case 47 (Poisson, 82 connections).
- Fig. 26A - Fig. 26D illustrate traffic cases 30, 31, 49, 50 (again showing contours of q, B, and m) for maximum admissible and minimum inadmissible numbers of connections, average rate lOkbit/s, average period 10 ms.
- Fig. 26B shows case 31 (discrete periodic, 14 connections);
- Fig. 26D shows case 50 (discrete period, 15 connections).
- Fig. 27A - Fig. 27B illustrate traffic cases 32, 33, 51, 52 (again for contours of q, B, and m) for maximum admissible and minimum inadmissible numbers of connections, average rate lOMbit/s, average period 10 ms.
- Fig. 27B shows case 33 (Poisson, 11 connections);
- Fig. 27D shows case 52 (Poisson, 12 connections
- Fig. 28A - Fig. 28D illustrate traffic cases 34, 35, 53, 54 (showing contours of q, B, and m) for maximum admissible and minimum inadmissible numbers of connections, average rate lOMbit/s, average period 100 s.
- Fig. 28B shows case 35 (discrete periodic, 0 connections);
- Fig. 29A - Fig. 29D illustrate traffic cases 36, 37, 55, 56 (showing contours of q, B, and m) for maximum admissible and minimum inadmissible numbers of connections, average rate lOMbit/s, average period 100 s.
- Fig. 29B shows case 37 (Poisson, 0 connections);
- Fig. 29D shows case 56 (Poisson; same as case 18).
- Fig. 30A shows case 38, 1 connection; same as case 19);
- Fig. 30B shows case 57 (2 connections).
Abstract
Description
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JP2000590349A JP2002533997A (en) | 1998-12-18 | 1999-12-17 | Connection admission control based on bandwidth and buffer usage |
CA002355290A CA2355290A1 (en) | 1998-12-18 | 1999-12-17 | Connection admission control based on bandwidth and buffer usage |
EP99964910A EP1142225A2 (en) | 1998-12-18 | 1999-12-17 | Connection admission control based on bandwidth and buffer usage |
AU30939/00A AU3093900A (en) | 1998-12-18 | 1999-12-17 | Connection admission control based on bandwidth and buffer usage |
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US36582699A | 1999-08-03 | 1999-08-03 | |
US09/365,826 | 1999-08-03 |
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EP (1) | EP1142225A2 (en) |
JP (1) | JP2002533997A (en) |
CN (1) | CN1335009A (en) |
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WO2002041591A2 (en) * | 2000-11-15 | 2002-05-23 | Telefonaktiebolaget Lm Ericsson (Publ) | Priority signaling for cell switching |
WO2003077588A1 (en) * | 2002-03-13 | 2003-09-18 | Telefonaktiebolaget L M Ericsson | Connection admission control in packet-oriented, multi-service networks |
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CN100359895C (en) * | 2004-11-12 | 2008-01-02 | 东南大学 | Method for implementing full digital wireless communication system using fast Fourier transform |
CN100347999C (en) * | 2005-10-28 | 2007-11-07 | 清华大学 | Method for connecting service process with service pre-process in network |
CN100376100C (en) * | 2005-10-28 | 2008-03-19 | 清华大学 | Method for adjusting service access time and decreasing service to achieve burst |
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US5581544A (en) * | 1993-12-24 | 1996-12-03 | Fujitsu Limited | Method and apparatus for evaluating QOS in ATM multiplexing apparatus in which priority control is performed and for controlling call admissions and optimizing priority control on the basis of the evaluation |
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- 1999-12-17 JP JP2000590349A patent/JP2002533997A/en not_active Withdrawn
- 1999-12-17 EP EP99964910A patent/EP1142225A2/en not_active Withdrawn
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- 1999-12-17 CA CA002355290A patent/CA2355290A1/en not_active Abandoned
- 1999-12-17 WO PCT/SE1999/002419 patent/WO2000038380A2/en not_active Application Discontinuation
- 1999-12-17 AU AU30939/00A patent/AU3093900A/en not_active Abandoned
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US5850385A (en) * | 1991-09-24 | 1998-12-15 | Kabushiki Kaisha Toshiba | Cell loss rate sensitive routing and call admission control method |
US5408465A (en) * | 1993-06-21 | 1995-04-18 | Hewlett-Packard Company | Flexible scheme for admission control of multimedia streams on integrated networks |
US5581544A (en) * | 1993-12-24 | 1996-12-03 | Fujitsu Limited | Method and apparatus for evaluating QOS in ATM multiplexing apparatus in which priority control is performed and for controlling call admissions and optimizing priority control on the basis of the evaluation |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
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US6993018B1 (en) | 1999-08-03 | 2006-01-31 | Telefonaktiebolaget Lm Ericsson (Publ) | Priority signaling for cell switching |
WO2002041591A2 (en) * | 2000-11-15 | 2002-05-23 | Telefonaktiebolaget Lm Ericsson (Publ) | Priority signaling for cell switching |
WO2002041591A3 (en) * | 2000-11-15 | 2002-07-25 | Ericsson Telefon Ab L M | Priority signaling for cell switching |
WO2003077588A1 (en) * | 2002-03-13 | 2003-09-18 | Telefonaktiebolaget L M Ericsson | Connection admission control in packet-oriented, multi-service networks |
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CA2355290A1 (en) | 2000-06-29 |
JP2002533997A (en) | 2002-10-08 |
AU3093900A (en) | 2000-07-12 |
TW512610B (en) | 2002-12-01 |
WO2000038380A3 (en) | 2000-11-09 |
CN1335009A (en) | 2002-02-06 |
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