JP2967337B2 - Resource reservation system in ATM end system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM (Asyn)
The present invention relates to a resource reservation system in an ATM end system connected to a (Transfer Mode) network.

[0002]

2. Description of the Related Art Generally, TCP / IP (Transmis
Sion Control Protocol / Int
When an application operating on an existing protocol, such as an Ethernet protocol, is operated on an ATM network, a modification for controlling the communication band when reserving resources of the ATM network is necessary. Need to be incorporated. In addition, protocols relating to ATM network resource reservation include:
Protocol RSVP (Resource Reserve)
Protocol (IE) (Inte
rnet Engineering Task Forc
e) Standardization is in progress.

Further, as an example of reserving a band by lowering a transfer rate when a reservation of a communication band has failed, Wakamiya et al. In the paper "ATM" of IEICE and IEICE Technical Report SSE94-114.
Performance evaluation of dynamic bandwidth reservation scheme using link information in LAN ". This method is an ACK / NACK method in which a band is reserved in burst units, and the reservation rate is re-reserved when reservation fails.

[0004]

An application that operates on an existing protocol such as TCP / IP is called an AT.
When operating on the M network, there is a problem that the communication band needs to be modified in order to control the communication band. Further, in the resource reservation protocol RSVP, if resources specified by the user cannot be secured, a call loss occurs, and there is a problem that flexibility is lacking. Further, like the ACK / NACK method described above, FRP (Fast Reservation P)
In the service class limited to the protocol, the retry is limited to the bandwidth or the bandwidth is fixedly increased or decreased. Therefore, the resource reservation method that can freely retry the desired communication parameter in the service class specified by the user. Is required.

Accordingly, the present invention allows for the incorporation of bandwidth control logic without modifying applications over existing protocols such as TCP / IP,
An object of the present invention is to reduce the scale of creation of bandwidth control when developing a new application. It is another object of the present invention to perform flexible bandwidth reservation by retrying without simply setting a call loss even when a resource specified by a user cannot be secured. Another object of the present invention is to allow a desired communication parameter to be freely changed in a service class specified by a user or an application and to retry.

[0006]

In order to solve such a problem, the present invention provides a setting means (resource reservation function unit) for setting an ATM connection independently of an application and a user information transfer protocol in an ATM end system. The setting means establishes a connection using a resource request list specified by a user or an application. As a result, it becomes possible to incorporate the logic of the band control without modifying the application on the existing protocol such as TCP / IP. In addition, it is possible to reduce the scale of creation of bandwidth control when developing a new application. Furthermore, even if the resources specified by the user cannot be secured, the communication parameters specified by the user or application are not simply determined as a call loss, and are not limited to retries or fixed increase / decrease of the bandwidth in the limited service class. Feel free to change and retry,
It is possible to raise the communication grade at a certain time while performing communication and reset the connection. AT having a function of notifying available resources
Since the combination of communication parameters that utilize the maximum resources within the range of resources notified from the M network is searched from the resource reservation list, the resources that can be used from the ATM network are notified when the connection is set and after the connection is established. Thus, it is possible to select a combination of communication parameters in the range of resources notified from the ATM network and utilizing the maximum resources from the resource request list, and set a connection.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an ATM end system to which the present invention is applied. 1, reference numeral 1 denotes an ATM end system, 2 denotes a communication application unit, 3 denotes a user information transfer protocol unit, 4 denotes a resource reservation function unit, 5 denotes an ATM driver, 6 denotes an ATM U-plane unit, and 7 denotes an ATM U-plane unit. Denotes an ATM signal control unit, and 8 denotes an ATM transmission line.

FIG. 2 is a diagram showing a data structure of a resource request list 10 designated by a user or an application referred to by the resource reservation function unit 4 constituting the ATM end system 1. Here, 10A is a service class used when setting an ATM connection.
In this service class 10A, the entry specifies a QoS parameter and a traffic parameter. The higher the entry, the higher the communication grade parameter is set, and the lower the entry, the lower communication grade parameter is set. Reference numeral 10B denotes a pointer that indicates which entry sets a connection. The PCR in the figure is the peak cell rate (Peak Cell Rate).
l Rate), and MCR indicates a minimum cell rate.

Next, FIG. 3 shows an SDL (functiona).
l Specification and Descri
FIG. 4 is a diagram showing a notation of “ption Language”. In the figure, reference numeral 11 denotes a state in communication. 12
Indicates a message transmission to another function block, and describes a message name, a transmission function block, and a reception function block. Reference numeral 13 denotes message reception from another function block, and describes a message name, a transmission function block, and a reception function block. Numeral 14 denotes an internal event setting, which indicates a timer start. 15 indicates occurrence of an internal event,
Here, the timer expires. In addition, 16 indicates a process, 17 indicates a judgment, and 18 indicates a connector.

FIGS. 4 and 5 are SDL diagrams for explaining the operation of the resource reservation function unit 4, which is the main function of the present invention. The operation of the main part of the present invention will be specifically described with reference to the block diagram of FIG. 1 and the data configuration diagram of FIG. 2 mainly on the SDL diagrams of FIG. 4 and FIG. 4 and 5, "Y" indicates "YES" (affirmative), and "N" indicates "NO" (negative).
Shall be expressed. The same applies to the following flow. FIG.
When the communication application unit 2 of the above makes a request for a communication connection to the user information transfer protocol unit 3, the user information transfer protocol unit 3 activates the resource reservation function unit 4 (step S2 in FIG. 4). The activated resource reservation function unit 4 identifies the user or the application and refers to the corresponding resource request list 10 shown in FIG.

In the resource reservation function unit 4, the resource request list 1
The first request "1" of "0" is taken out and the ATM signal control unit 7
Request a connection setting (steps S3 and S4 in FIG. 4), and transition to a response waiting state (step S5 in FIG. 4). Here, if the connection request is successful (step S6 in FIG. 4), it is transmitted to the user information transfer protocol unit 3 together with the acquired resource information such as the bandwidth (step S7 in FIG. 4), and the communication state (step S7 in FIG. 4) is established. Transit to step S10) of FIG. Further, when the resource reservation function unit 4 fails to set up the connection while waiting for a response (step S11 in FIG. 4), it determines whether the request output to the ATM signal control unit 7 is the last of the resource reservation list 10 (FIG. 4). In step S12), if it is final, the connection setting failure is notified to the user information transfer protocol unit 3 (step 13 in FIG. 4), and the process ends (step S14).

On the other hand, if the request output to the ATM signal control unit 7 is not the last list of the resource reservation list 10, the next request is extracted from the resource request list 10 (step S15 in FIG. 4), and the ATM signal is again output. It issues a connection setting request to the control unit 7 (step S4 in FIG. 4), and transitions to a response waiting state (step S5 in FIG. 4). Further, when the connection is successfully set in the response waiting state (step S6 in FIG. 4), the connection is transmitted to the user information transfer protocol unit 3 together with the resource information such as the acquired bandwidth (FIG. 4).
Step S7), the output request is the resource request list 10
(Step S in FIG. 4)
8) In addition, if the timer is not the first one, the timer is started (step S9 in FIG. 4), and then the state transits to the communicating state (step S10 in FIG. 4).

Here, the communication state (step S1 in FIG. 5)
When the timer expires in 6) (step S1 in FIG. 5)
7) Retrieve communication parameters from the request of the first entry of the resource request list 10 to the request immediately before the request already used for communication, and retry the connection setting (steps S18, S19, FIG. 5). S20, S2
1, S26, S27). If the communication parameter is successfully changed in this process (Step S22 in FIG. 5), the change is transmitted to the user information transfer protocol unit 3 together with the acquired resource information such as the bandwidth (Step S7 in FIG. 4).
If the output request is not the first one in the resource request list 10, the timer is started (step S9 in FIG. 4) and the state transits to the communicating state (step S10 in FIG. 4). If the output request is the first one in the resource request list 10, the timer is not started. On the other hand, the above process (steps S18, S19, S20, S21, S26, S27 in FIG. 5)
If the change of the communication parameters fails in step ("Y" in step S19 in FIG. 5), the timer is started (step S24 in FIG. 5), and then the state transits to the communicating state (step S25 in FIG. 5). .

Next, FIG. 6 is a diagram showing an operation sequence between each unit in the ATM end system 1 and an operation sequence between each unit in the system 1 and a network (ATM network).
This corresponds to claim 2 of the present invention. In the figure, 19 is a message composed of the parameters of the first entry of the resource request list 10 transmitted from the resource reservation function unit 4 to the ATM signal control unit 7, and 21 is the second entry of the resource request list 10. 20 and 22 denote call setting messages from the ATM signal control unit 7 to the network, respectively.

Reference numeral 23 denotes a communication state (step S16 in FIG. 5).
A message composed of parameters of the first entry of the resource request list 10 transmitted to the signal control unit 7;
Numeral 24 indicates a bandwidth change message during communication from the ATM signal control unit 7 to the network. Reference numerals 25 and 26 denote connections between the ATM U-plane unit 6 and the network, and indicate the size of the bandwidth secured by the thickness of the line shown in the figure. The data transfer speed between the communication application unit 2 and the user information transfer protocol unit 3 is determined by the number of times of control movement per time. If the transfer speed of the lower layer is high, the control transfer increases and the transfer speed increases. Become. User information transfer protocol unit 3 and ATM U-plane unit 6
For example, when the user information transfer protocol unit 3 uses a window control protocol such as TCP, the data transfer speed between the two depends on the window size.

The operation of the main part of the present invention will be described mainly with reference to the sequence diagram of FIG. 6 and the block diagram of FIG. 1 and the SDL diagrams of FIG. 4 and FIG. When the communication application unit 2 activates the user information transfer protocol unit 3, the user information transfer program unit 3 activates the resource reservation function unit 4 (step S2 in FIG. 4) and performs call setting according to the resource request list 10. Here, in FIG. 6, the connection is established by the second request “2” indicated by reference numeral 21 (step S in FIG. 4).
3, S4, S5, S11, S12, S15, S4, S
5, S6, S7, S8, S9, S10), the data transfer from the communication application unit 2 is started (reference numeral 25 in FIG. 6). Thereafter, at a later timing, data transfer is performed again according to the resource request list 10. Here, the band is changed during communication (reference numeral 24 in FIG. 6), and then the data transfer band is extended (reference numeral 26 in FIG. 6). Where 2
5 and 26 are the same virtual connection.

FIG. 7 is a diagram showing an operation sequence between each unit in the ATM end system 1 and an operation sequence between each unit in the system 1 and the network, which corresponds to claim 3 of the present invention. It is. The difference between FIG. 7 and FIG. 6 is that a new connection indicated by reference numeral 32 is set instead of changing the communication bandwidth during a request “1” indicated by reference numeral 31. That is, by the call setting indicated by reference numeral 30,
After the data transfer indicated by reference numeral 3 is performed and a new connection is set by the call setting of reference numeral 32, the data transfer indicated by reference numeral 34 is performed by the call setting indicated by reference numeral 30, and
The data transfer indicated by reference numeral 35 is performed by the call setting indicated by.
Note that 33 and 34 are the same virtual connection.

Next, FIG. 8 shows an ATM end system 1 and an AT for notifying network resources usable by the end system 1.
FIG. 4 is an explanatory diagram for explaining message exchange with an M exchange device, and corresponds to claim 4 of the present invention. In the figure, reference numeral 38 denotes an ATM exchange for notifying the ATM end system 1 of information on available network resources. Also,
Reference numeral 37 denotes a message for notifying the ATM end system 1 of available resource information from the ATM exchange 38, and reference numeral 39 denotes a message for notifying the ATM end system 1 of information on resources to be used to the ATM exchange 38.

FIG. 9 is a flowchart showing an algorithm for retrieving from the resource request list 10 a combination of communication parameters in the range of resources notified from the network (ie, the ATM network) and utilizing the maximum resources. . Referring mainly to the flow chart of FIG. 9 and FIG.
An algorithm for searching the resource request list 10 for a combination of communication parameters that utilize the maximum resources in the range of resources notified from the TM network will be described.

In setting up a call to the ATM exchange 38, parameters having larger communication grades such as PCR and MCR in the resource request list 10 are set to parameters having a higher communication grade (α1, α2,..., Αk). In the resource request list 10
Not shown CLR (Cell Loss Ratio)
o), the parameter with the smaller numerical value such as the higher communication grade is (β1, β2,..., βm), and the combined parameters are (α1, α2,..., αk, β1, β2,. β
m).

Here, the i-th request i in the resource request list 10 is (αi1, αi2,..., Αik, βi1, βi2,.
im) and write. The parameters notified by a message (reference numeral 37 in FIG. 8) from the ATM switch 38 are (α′1, α′2,..., Α′k, β′1, β′2,
..., β'm).

At this time, the ATM in the resource request list 10
A pointer i (reference numeral 10B in FIG. 2) corresponding to a combination of communication parameters in the range of resources notified from the exchange 38 and utilizing the maximum resources is αij ≦ α′j (j = 1, 2,. .., K) and the minimum i that satisfies β′j ≦ βij (j = 1, 2,..., M). Step S38 in FIG. 9 shows a case where such i exists, and the resource request list 10
, The request i corresponding to the pointer i is within the range of the resources notified from the ATM exchange 38 and is a combination of communication parameters that utilizes the maximum resources.

[0023]

As described above, according to the present invention, A
In the TM end system, setting means for setting an ATM connection independently of an application or a user information transfer protocol is provided. The setting means establishes a connection using a resource request list designated by a user or an application. It is possible to incorporate the band designation logic without modifying the application on the existing protocol such as / IP. Further, for a new application, the scale of creation related to band control can be reduced by using the resource reservation function unit as a common library. Furthermore, even if the resources specified by the user cannot be secured, the communication parameters specified by the user or application are not simply regarded as a call loss, and are not retries limited to the bandwidth with a limited service class or fixed increase / decrease of the bandwidth. It is possible to freely change and retry, or to reset the connection by increasing the communication grade at a certain time while performing communication. In addition, to improve the communication grade, the available bandwidth can be extended while maintaining one ATM connection,
The available bandwidth can be expanded by newly adding another ATM connection. In addition, since a combination of communication parameters within the range of resources notified from the ATM network having a function of notifying usable resources and utilizing the maximum resources is searched from the resource reservation list, it is possible to search for a combination of resources at the time of connection setting. After the connection is established, the available resources from the ATM network are notified and the AT is selected from the resource request list.
The connection can be set or reset by selecting a combination of communication parameters that utilize the maximum resources in the range of resources notified from the M network.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an ATM end system to which the present invention is applied.

FIG. 2 is a diagram showing a configuration of a resource request list specified by a user or an application referred to by a resource reservation function unit in the ATM end system.

FIG. 3 is a diagram illustrating SDL notation.

FIG. 4 is a diagram for explaining the operation of a resource request function unit in SDL notation.

FIG. 5 is a diagram for explaining the operation of a resource request function unit in SDL notation.

FIG. 6 is a diagram showing an operation sequence between each block in the ATM end system and between each block and the ATM network.

FIG. 7 is a diagram showing an operation sequence between each block in the ATM end system and between each block and the ATM network.

FIG. 8 is a diagram showing message exchange between an ATM end system and an ATM network (ATM exchange).

FIG. 9 is a flowchart showing an algorithm for searching a resource request list for a combination of communication parameters that utilize the maximum resources in the range of resources notified from the ATM network.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... ATM end system, 2 ... Communication application part, 3 ... User information transfer protocol part, 4 ... Resource reservation function part, 5 ... ATM driver part, 6 ... ATM up plane part (ATM U-plane part), 7 ... ATM Signal control unit, 8: ATM transmission line, 10: Resource reservation list, 10A
... ATM signal parameters (service class, PCR, M
CR and other QoS parameters, traffic parameters),
10B: Pointer, 38: ATM switch, 37, 39 ...
message.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04L 12/28

Claims (2)

(57) [Claims] 1. An ATM end system connected to an ATM network, comprising setting means for setting a connection with the ATM network independently of an application and a user information transfer protocol, wherein the setting means is specified by a user or an application. A connection with the ATM network is established using the resource request list obtained, and after the connection is established, communication is performed while the communication parameters are changed according to the resource request list, the connection is reset, and the connection is established. If the communication fails, the communication parameters are changed in accordance with the resource request list and the connection is reset. 2. The method according to claim 1, wherein the setting unit is notified of a resource available from an ATM network.
And from the resource request list through the ATM network.
Communication that utilizes the maximum resources within the range of known resources
The connection is set by selecting the combination of communication parameters, and after the connection is established, it is used from the ATM network.
Resource available and whether it is in the resource request list
The maximum within the range of resources notified from the ATM network
Select a combination of communication parameters to utilize the resources of
A resource reservation system in an ATM end system, wherein a connection is reset by a connection .