Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
• • 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
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/10—Flow control; Congestion control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/10—Flow control; Congestion control
  • H04L47/20—Traffic policing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/50—Queue scheduling
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/50—Queue scheduling
  • H04L47/52—Queue scheduling by attributing bandwidth to queues
  • H04L47/522—Dynamic queue service slot or variable bandwidth allocation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/50—Queue scheduling
  • H04L47/62—Queue scheduling characterised by scheduling criteria
  • H04L47/6215—Individual queue per QOS, rate or priority
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L47/00—Traffic control in data switching networks
  • H04L47/50—Queue scheduling
  • H04L47/62—Queue scheduling characterised by scheduling criteria
  • H04L47/625—Queue scheduling characterised by scheduling criteria for service slots or service orders
  • H04L47/627—Queue scheduling characterised by scheduling criteria for service slots or service orders policing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L49/00—Packet switching elements
  • H04L49/20—Support for services
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L49/00—Packet switching elements
  • H04L49/25—Routing or path finding in a switch fabric
  • H04L49/253—Routing or path finding in a switch fabric using establishment or release of connections between ports
  • H04L49/254—Centralised controller, i.e. arbitration or scheduling
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L49/00—Packet switching elements
  • H04L49/30—Peripheral units, e.g. input or output ports
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L49/00—Packet switching elements
  • H04L49/30—Peripheral units, e.g. input or output ports
  • H04L49/3081—ATM peripheral units, e.g. policing, insertion or extraction
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L49/00—Packet switching elements
  • H04L49/50—Overload detection or protection within a single switching element
  • H04L49/501—Overload detection
  • H04L49/503—Policing
• • 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
  • H04L2012/5631—Resource management and allocation
  • H04L2012/5636—Monitoring or policing, e.g. compliance with allocated rate, corrective actions
  • H04L2012/5637—Leaky Buckets
• • 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
  • H04L2012/5647—Cell loss
• • 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

Definitions

• the present invention relates generally to an apparatus and method for providing guaranteed frame rate (GFR) service in an asynchronous transfer mode (ATM) switch.
• GFR guaranteed frame rate
• ATM asynchronous transfer mode
• the guaranteed frame rate (GFR) service is intended to support non-real-time applications in the ATM network. It is designed for applications that may require a minimum rate guarantee and can benefit from accessing additional bandwidth dynamically available in the network.
• the GFR does not require adherence to a flow control protocol unlike the Available Bit Rate (ABR) service.
• the service guarantee is performed based on AAL-5 PDUs (ATM Adaptation Layer 5 Protocol Data Unit: frames).
• a frame refers to a unit, which binds a plurality of cells, to be transmitted on a transmission line. While frame structure varies depending on at which AAL sub-layer a particular frame is used, a frame is typically comprised of a
• a frame is identified by marking the last cell of the frame with the payload type field PT of an ATM cell header.
• the network discards cells at the frame level rather than at the cell level. Therefore, the guaranteed frame rate (GFR) service requires that user data cells are organized in the form of frames that can be delineated at the ATM layer.
• GFR guaranteed frame rate
• the end system specifies a peak cell rate (PCR) and a minimum cell rate (MCR) that is defined along with a maximum frame size (MFS), that is, a maximum number of cells per frame.
• PCR peak cell rate
• MCR minimum cell rate
• MFS maximum frame size
• the user may always send cells at a rate up to the peak cell rate (PCR), but the network only commits to carry cells in complete frames at the minimum cell rate (MCR). Traffic beyond the MCR will be delivered within the limits of available resources.
• the above service guarantee implies that if the user sends frames that do not exceed the MCR, then the user should expect to see the frames delivered with minimum losses.
• the GFR service also allows the user to send in excess of the MCR, but the excess traffic will only be delivered within the limits of available resources. Furthermore, the service specifies that the excess traffic from each user should have access to a fair share of the available sources.
• the user can send frames either unmarked or marked.
• MCR Minimum cell rate
• the network is only allowed to tag cells in unmarked frames if the user has requested the tagging option, either via signaling (for Switched Virtual Channels: SVCs) or via subscription (for Permanent Virtual Channels: PVCs).
• a cell is called tagged when the network sets its CLP bit to 1. Otherwise, tagging by the network is not applicable.
• the GFR service category only applies to virtual channel connection as frame delineation is not generally visible in a virtual path connection.
• GFR guaranteed frame rate
• GFR.1 There are two versions of guaranteed frame rate (GFR), GFR.1 and GFR.2. They differ with respect to the treatment of the Cell Loss Priority (CLP) bit based on a frame-based generic cell rate algorithm (F-GCRA) test.
• CLP Cell Loss Priority
• F-GCRA frame-based generic cell rate algorithm
• the network may tag frames that can not pass the F-GCRA test as in GFR.2 version, the network can delineate frames to be transmission-guaranteed by their CLP bits according to the states of the frames and the network. If such frame delineation is viable, there can be system implementation choices in terms of implementation simplicity and performance. However, in case the network is unable to tag as in GFR. l, the network should rely on the CLP bits marked by the user to delineate frames to be guaranteed. A cell is coriforming if the cell conforms to a traffic contract preset by the network, and a cell is non-conforming if it does not conform to the traffic contract. Then, in the case that tagging is not allowed in the network, the non- conforming cells may not be delineated, thus making it difficult to process the non- conforming cells.
• an object of the present invention to provide an apparatus and method for efficiently providing the GFR service in ATM according to the characteristic of a network by discriminating between a conforming cell and a non- conforming cell and storing them in different output buffered queues.
• GFR guaranteed frame rate
• a cell conformance portion applies a test to each cell in an input frame with respect to generic cell rate algorithm (GCRA), cell loss priority (CLP) bit, and maximum frame size (MFS); sets the conforming bit (CB) of each cell in the frame to a conforming value if all cells of the frame pass the test; and, sets the CB of each cell in the frame to a non- conforming value if at least one cell of the frame does not pass the test.
• GCRA generic cell rate algorithm
• CLP cell loss priority
• MFS maximum frame size
• a buffer management portion allocates cells with CBs set a conforming value to a high priority queue; allocates cells with CBs set a non-confo ⁇ ning value to a low priority queue; transmits the cells allocated to the high priority queue with a minimum cell rate (MCR) guaranteed; and, transmits the cells allocated to the low priority queue at a cell rate allowed by a bandwidth available in a network.
• MCR minimum cell rate
• a method for providing GFR service in an ATM switch comprising the steps of: (a) applying a test to each cell in an input frame of a cell conformance portion for with respect to generic cell rate algorithm (GCRA), cell loss priority (CLP) bit, and maximum frame size (MFS);
• GCRA generic cell rate algorithm
• CLP cell loss priority
• MFS maximum frame size
• step (b) setting a conforming bit (CB) of each cell in the frame to a conforming value if all cells of the frame pass the test applied in step (a);
• step (c) setting the CB of each cell in the frame to a non-confo ⁇ ning value if at least one cell of the frame does not pass the test applied in step (a);
• step (a) includes testing each cell in the cell conformance portion by:
• test results including:
• step (b) including:
• step (d) includes:
• step (d)(3) the controlling of the high priority and low priority queues by the queue controller recited in step (d)(3) includes:
• the GFR service providing method includes having the queue controller immediately discard cells with CLP bits set in the low priority queue when the network is congested.
• FIG. 1 is a block diagram of an ATM GFR service providing apparatus according to the embodiment of the present invention
• FIG. 2 is a flowchart illustrating a cell conformance test procedure in the ATM GFR service providing apparatus according to the embodiment of the present invention.
• FIG. 3 illustrates a conforming cell and a non-conforming cell in the ATM GFR service providing apparatus according to the embodiment of the present invention.
• FIG. 1 is a block diagram of an ATM guaranteed frame rate (GFR) service providing apparatus and method according to an embodiment of the present invention.
• GFR ATM guaranteed frame rate
• the ATM GFR service providing apparatus and method of the present invention is comprised of a cell conformance portion 100 and a buffer management portion 110.
• the cell conformance portion 100 includes a cell conformance tester 101 and a confo ⁇ ning bit (CB) setter 102 connected to the cell conformance tester 101.
• the buffer management portion 110 includes a cell allocator 111 connected to the conforming bit setter 102, a buffered queue 113 connected to the cell allocator 111, and a queue controller 112 for controlling the buffered queue 113.
• the cell conformance portion 100 applies a cell conformance test to each cell in the input frame of a GFR connection and sets a CLP bit for the cell.
• the cell conformance tester 101 tests each cell in the input frame of a GFR connection on predetermined traffic parameters. For example, generic cell rate algorithm (GCRA), cell loss priority (CLP) bit, and maximum frame size (MFS) that will be later described.
• GCRA generic cell rate algorithm
• CLP cell loss priority
• MFS maximum frame size
• a traffic parameter describes an inherent characteristic of a traffic source. It may be quantitative or qualitative. Typical traffic parameters include peak cell rate (PCR), sustainable cell rate (SCR), minimum cell rate (MCR), and maximum frame size (MFS).
• PCR peak cell rate
• SCR sustainable cell rate
• MCR minimum cell rate
• MFS maximum frame size
• a definition for PCR is a reciprocal of the minimum inter-arrival time of cells within a frame.
• ATM layer functions may alter the traffic characteristics of connections by introducing cell delay variation.
• cells of a given connection may be delayed while cells of another connection are being inserted at the output of the multiplexer.
• OAM Operaation Administration and Management
• some cells may be delayed while physical layer overhead or OAM (Operation Administration and Management) cells are inserted. Consequently with respect to the peak emission interval T (i.e., the inverse of the contracted PCR), some randomness may affect the inter-arrival time between consecutive cells of a connection as monitored at the UNI (User Network Interface).
• the upper bound on the "clumping" measure is cell delay variation tolerance (CDVT).
• the GCRA is used to define conformance with respect to the traffic contract. For each cell arrival, the GCRA determines whether the cell conforms to the traffic contract of the connection.
• the GCRA is a virtual scheduling algorithm or a continuous-state Leaky Bucket Algorithm which is well known in the art.
• the GCRA is used to define the relationship between peak cell rate (PCR) and cell delay variation tolerance (CDVT), and the relationship between SCR, and Burst Tolerance (BT).
• PCR peak cell rate
• CDVT cell delay variation tolerance
• BT Burst Tolerance
• the GCRA is defined with two parameters: the increment (I) and the limit (L).
• the notion "GCRA (I, L)" means the generic cell rate algorithm with the value of the increment parameter set equal to I and the value of the limit parameter set equal to L.
• the GFR conformance definition is based on the conformance of each cell of a frame with respect to the following conditions.
• a frame is conforming if all cells within the frame are coiiforrning, but non-conforming if one or more of its cells are non-conforming.
• a user generated cell is confo ⁇ ning if all of the following three conditions are met:
• the cell conforms to GCRA(1/PCR, CDVT).
• the CLP bit of the cell has the same value as the CLP bit of the first cell of the frame.
• the cell either is the last cell of the frame or the number of cells in the frame up to and including this cell is less than MFS.
• FIG. 2 is a flowchart illustrating a GFR cell conformance test of each cell in an input frame in the cell conformance tester 101 of FIG. 1.
• the cell conformance tester 101 tests the cell according to the GCRA in step 210 with the parameters 1/PCR and CDVT indicating the increment value and the limit value, respectively.
• 1 PCR indicates an expected arrival time of the next cell and is updated upon every cell arrival of a frame.
• the CDVT specifies the upper and lower error limits for 1/PCR. If each cell arrives within the CDVT, the cell conforms to the GCRA. Then, the procedure goes to step 220.
• the cell conformance tester 101 registers the CLP bit of the first cell in an inner register in step 221. If the cell is not the first cell of the frame in step 220, the cell conformance tester 101 dete ⁇ riines whether the CLP bit of the cell has the same value as the CLP bit of the first cell registered in the inner register in step 222. If they are the same, the CLP bit of the cell is conforming and if they are different, the cell is non-conforming.
• the cell conformance tester 101 determines whether the cell is the last cell of the frame in step 230. If the cell is not the last cell of the frame, the cell conformance tester 101 determines whether the number of cells received so far is less than MFS in step 231. Upon cell arrival, it is determined whether the number of cells received up to that time is less than the MFS, and if the cell number is less than the MFS, the cell conforms to the test of the MFS. If the cell number is greater than the MFS, the cell is not coirforming to the MFS test. If the cell is the last cell of the frame, the cell is also conforming to the MFS.
• the cell meets all the above conditions, it is said that the cell is conforming in step 240. If at least one of the conditions is not satisfied in steps 210, 222, and 23 1, the cell is defined as non-confo ⁇ ning in step 241.
• the GCRA test is applied to every cell. Therefore, even in case a cell arrives above a congested threshold value, the cell is protected as the other cells of the frame as long as the cell satisfies the above conditions.
• each cell of the input frame passes the cell conformance test with respect to the algorithm and traffic parameters, the cell is fed to the conforming bit setter 102 through a conforming path 103. If the frame has at least one cell that has not pass the cell conformance test, the cells in the frame are fed to the conforming bit setter 102 through a non-conforming path 104.
• FIG. 3 illustrates a confoirriing cell and a non-conforming cell in the ATM GFR service providing apparatus according to the embodiment of the present invention.
• the conforming bit setter 102 transmits each cell with its CB set to zero or one in a frame to the buffered queue 110.
• the queue controller 110 transmits the cells input to the high priority queue 114, providing an MCR service guarantee.
• the queue controller 110 sets a congested queue depth at which the network is congested. Unless the queue value of the cells allocated in the low priority queue 115 is greater than the congested queue depth, the queue controller 110 allows the cells to access a fair share of the available bandwidth in the network with other ATM service categories like ABR. In addition, the queue controller 110 transmits the cells allocated to the low priority queue 115 at a cell rate according to the available bandwidth of the network.
• the queue controller 110 discards the cells at the frame level, thereby managing the performance (transmission rate) of the network.
• a discarded cell in frames does not imply concmrent discardation of all cells in one frame, rather it determines a frame to be discarded and a selective discardation of the cells in the frame according to CLP bits.
• the present invention has the same effect as observed in GFR.2 where the network can tag using CB within the system. Besides, a cell conformance test is given to a cell input to the network even for GFR. l, which is characterized in that tagging not is allowed in the network, thus that the present invention can protect a cell that is against a connection contract of the network but unmarked by a user if cell is considered to be significant. The resulting traffic management enables the network to be protected against users who terminates or breaches the connection contract.

Applications Claiming Priority (3)

Publications (1)

Family

ID=19617137

Family Applications (1)

Country Status (9)

Families Citing this family (9)

Family Cites Families (1)

• 1999
  • 1999-10-27 KR KR1019990046846A patent/KR100306166B1/ko not_active IP Right Cessation
• 2000
  • 2000-10-25 CN CNB008024340A patent/CN1157893C/zh not_active Expired - Fee Related
  • 2000-10-25 CA CA002352828A patent/CA2352828C/en not_active Expired - Fee Related
  • 2000-10-25 AU AU11752/01A patent/AU763424B2/en not_active Ceased
  • 2000-10-25 EP EP00973215A patent/EP1142205A1/en not_active Withdrawn
  • 2000-10-25 JP JP2001533689A patent/JP2003513518A/ja active Pending
  • 2000-10-25 WO PCT/KR2000/001207 patent/WO2001031854A1/en not_active Application Discontinuation
  • 2000-10-25 RU RU2001117504/09A patent/RU2214062C2/ru not_active IP Right Cessation
  • 2000-10-27 TW TW089122749A patent/TW513878B/zh not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events