JP2654262B2 - Window size setting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a window size setting method for packet switching.

[0002]

2. Description of the Related Art Conventionally, a window size setting method in packet switching includes an end-to-end (End-to-End, EE) method in which data transmission after a communication path is set is directly transmitted and received by data terminals at both ends. And a link-by-link (Lx) link for transmitting data for each ring forming between the terminal and the exchange.
L) It is fixedly set in advance for each packet switching system as in either one of the methods.

In a packet switching system, the number of octets having a maximum length is determined, and each terminal and each exchange have a limited storage capacity for received data. Is indicated as a window size (WS), which is a limited transmission amount of the DT packet.

FIG. 6 is a connection diagram showing an example of a packet transmission path. As shown in FIG. 6, when the calling terminal 71 connects to the called terminal 73 via the packet network 72 and sets up a communication path, the communication path whose calling side is the DT packet sending side is a subscriber attribute. , A line attribute and a call attribute, a window size A (WSZA), and a communication path having the called side as the DT packet transmitting side has the same window size B (WZA).
SZB).

FIG. 4A is a flowchart showing an example of setting a communication path when the packet switching system is an end-to-end (EE) type.

As shown, both the calling terminal and the called terminal have E
-E type, the calling terminal has WS = 15, and the called terminal has WS = 10. The calling request (CR) packet transmitted by the calling terminal indicates its own WS = 15 to WSZA and WSZB.

Since the switching network is of the EE type, the calling station and the called station transfer the CR packet with WSZA = WSZB = 15. Since the called terminal has WS = 10 and WS = 15 is unacceptable, the returning call accepting (CC) packet indicates its own WS = 10 to WSZA and WSZB.

[0008] Upon receipt of this CC packet, the calling terminal sets WS = 10 and transmits the subsequent DT packet to WSZA.
= 10. Of course, the called terminal is WSZB = 10
Sends a DT packet.

FIG. 5A is a connection diagram showing an example of the communication path shown in FIG. As shown, the transmitting terminal 11 has WS = 15 and transmits the DT packet to the receiving terminal 41 having WS = 10 via the packet stations 51 and 52 of the packet network 50. In this case, the packet stations 51 and 52 transfer the received DT packet as it is after setting the communication path with the CR packet and the CC packet.

FIG. 4B is a procedure diagram showing an example of setting a communication path when the packet switching system is a link-by-link (L × L) type.

As shown, both the calling terminal and the called terminal are L
× L type, the window size of the link from the calling terminal to the calling station is WS = 6, the window size of the link from the calling station to the called station is WS = 10, and the called station is the called terminal. The window size of the link up to WS = 4
Is set for this call.

That is, the CR and CC packets transmitted to the link between the calling terminal and the calling station are both WSZA = W
SZB = 6, CR to link between calling and called stations
Both the CC packet is WSZA = WSZB = 10, and the CR / CC packet to the link between the called station and the called terminal is both WSZA = WSZB = 4. Therefore, the window size of the DT packet is set for each link in the same manner as the CR / CC packet.

FIG. 5 (B) is a connection diagram showing an example of the communication path of FIG. 4 (B). The originating terminal 12 transmits to the packet station 61 with the link size WS = 6, the packet station 61 transmits the DT packet to the packet station 62 with WS = 10, and the packet station 62 transmits the DT packet to the terminating terminal 42 with WS = 4. I do.

[0014]

In the conventional window size setting method described above, the window size of the DT packet transmitted from the subscriber terminal and the packet station is fixedly set by the packet switching system. , EE type L × L type subscriber terminals are mixed, the window size is set to the L × L type. Therefore, when the window size is small in the link between packet stations, the size is limited to this size. Thus, there is a problem that the data transfer efficiency of the EE type subscriber terminal is reduced.

An object of the present invention is to transmit whether an EE type or an L × L type is used as a flow control type of a subscriber terminal,
An object of the present invention is to provide a window size setting method which solves the above-mentioned problem by storing the packet size and setting a window size.

[0016]

According to the window size setting method of the present invention, in a window size setting method in packet switching, a call request (CR) packet between stations is provided with a flow control type (end-to-end) of a calling terminal. Network type (N or link-by-link type)
U) information, and network use (NU) information indicating the flow control type of the called terminal to the call acceptance (CC) packet between the stations, and each station receiving the flow control type receives this information. The flow control type is set and stored for each call, and while the flow control type passes the received packet as it is to the end-to-end (EE) type communication path, the link by link (L × L) For type, transfer packet processing is performed with the window size set for the link.

[0017]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention and an additional format.

As shown in FIG. 1, a calling terminal 10 is accommodated and connected to a calling station 20, and is connected to a called terminal 40 via a called station 30 by a CR (call request) packet.

The packet station, together with the calling station 20, the called station 30, and the relay station (not shown), has type memories 21 and 31 for storing the types of the calling terminal and the called terminal for each call. .

Since the calling station 20 which has received the CR packet stores the flow control type (EE / L × L) of the calling terminal 10, the calling station 20 records the flow control type in the type memory 21 in correspondence with the call and also uses the network utility. A (NU) format is created, added to the CR packet, and transmitted to the called station 30.

The called station 30 identifies the flow control type of the calling terminal 10 from the received NU format, records the flow control type in the calling terminal type area of the type memory 31, and transmits a CR packet to the called terminal 40.

The called terminal 40 receives the call request (CR) packet, and returns a call accepted (CC) packet to the called station 30 when the preparation for accepting the data (DT) packet is completed.

When the called station 30 receives the CC packet, it stores the flow control type of the called terminal 40.
The flow control type is formed in the NU format and transmitted to the calling station 20 together with the CC packet.

When receiving the (CC + NU) packet, the calling station 20 confirms the calling terminal type and the called terminal type, and corrects the record when the types are different.

As shown in the figure, the NU format is such that octet number 1 is a binary code 1 with bit numbers 1.2, binary code 0 with bit numbers 3 to 8, and octet number 2 is a binary code with bit numbers 1.2. Indicates the control type, and is a binary code 0 with bit numbers 3 to 8. The flow control type is bit numbers 1 and 2, the EE type is binary code 00,
FIG. 1 illustrates that the L × L type is a binary code 10.

The formation of the NU format causes the packet station to create a new procedure, but at the subscriber terminal it is no different from the conventional one.

FIG. 2 is a flowchart showing one embodiment of the main operation of the packet station according to the present invention.

When the packet station receives the CR packet from the calling terminal (101), the packet station looks up or identifies the flow control type of the calling terminal and stores it in the type memory (102).
I do. Next, the packet station forms a NU format (103) and transmits a CR + NU packet to the link to which the packet station is connected (104).

This CR + NU packet is received (111).
The packet station analyzes the NU format (112)
Then, the flow control type of the calling terminal is identified and stored in the type memory (113). Determine the type of calling terminal (1
14) In the case of the EE type, the packet station transfers the received value of the window size WSZA from the calling side as it is (115), while in the case of the L × L type, the packet station transmits the window size of the link to be transmitted. The WSZA is transmitted with the link size attached (116).

When the packet station receives the CC packet, the description of the above procedure will explain the CR packet as a CC packet, the CR + NU packet as a CC + NU packet, the calling terminal as a called terminal, and the WSZA as a WSZB. Applicable by change.

FIG. 3A shows a case where the calling terminal is of the EE type and WS = 15, the called terminal is of the L × L type, and the calling terminal, the calling station, the called station, and the called terminal. FIG. 7 is a procedure diagram showing a case where the window size of each link is WS = 6.10.4.

In this case, the calling terminal notifies its own window size by WSZA = WSZB = 15 by means of a CR packet, and indicates the EE type in the NU format between packet stations and stores it in the type memory.

In the CC packet returned in response to the CR packet, the called terminal has a value equal to or smaller than the value of the received WSZA and WSZB. In the example of FIG. 3A, WSZA = WSZB.
= 4 is transmitted.

The called station stores the L × L type of the called terminal in the type memory by receiving the CC packet next to the EE type of the calling terminal.
While the received WSZA = 4 is set, WSZB = 10 is set in the link size and transmitted to the calling station.

Similarly, the calling station sends WSZA = 4 to the calling terminal.
And WSZB = 6.

Therefore, the calling terminal transmits the DT packet to the WSZ
While A = 4 and transfer to the called terminal with the same size, the DT packet transmitted from the called terminal is of L × L type and the window size is set by WSZB = 4 · 10 · 6.

FIG. 3B is a flowchart showing an example of an L × L type calling terminal and an EE type called terminal with WS = 10.

The calling terminal uses WSZA = WSZ for each link.
In each of B = 6, 10.4, the CR packet is transferred, and the called terminal returns a CC packet with a value equal to or less than the received WS value and within its own size, and WSZA = WSZB = 4.

The calling station and the calling station that transfer this CC packet have the WSZA as the link size and the WSZB =
4 is transferred as it is because of the EE type, and the DT packet is transferred from the called terminal to the calling terminal with the same size.

The case where the calling terminal and the called terminal are of the same type is shown in FIG.

In the present embodiment, the window size of each link is illustrated and described with a fixed value in FIGS. 3 and 4, but the subscriber attribute, the line, and the like are set for each call, each line, and each set communication path. Since the window size is determined according to the attributes and the call attributes, usually, the values do not always match.

[0042]

As described above, according to the present invention, the flow control type of the data terminal is formed in the format of a network utility, transferred between packet stations and stored, and the calling side and the called side are connected. By executing the stored flow control type data packet transfer procedure for each round trip of the communication path, the end-to-end (EE) type data terminal transfers data regardless of the relay link window size. This has the effect of enabling flow control with high data transfer efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a window size setting method according to the present invention and a format showing an example of a network utility.

FIG. 2 is a flowchart showing an example of a main operation of the packet station according to the present invention.

FIG. 3 is a flowchart illustrating an example of packet transmission between data terminals having different types of flow control types according to the present invention;

FIG. 4 is a procedure diagram showing an example of packet transmission between data terminals having the same type of flow control type.

FIG. 5 is a connection diagram illustrating an example of a communication path according to FIG. 4;

FIG. 6 is a connection explanatory diagram showing an example of a packet transmission path.

[Explanation of symbols]

 Reference Signs List 10 calling terminal 20 calling station 21, 31 type memory 30 called station 40 called terminal 101 to 116 procedure CC call acceptance CR call request NU network utility WS window size WSZA window from caller to caller Size WSZB Window size from callee to caller

Claims (1)

(57) [Claims] 1. In a window size setting method in packet switching, a network use indicating a flow control type (end-to-end type or link-by-link type) of a calling terminal in a call request (CR) packet between stations. (NU) information, and network use (NU) information indicating the flow control type of the called terminal to the call acceptance (CC) packet between the stations, and each station receiving the flow control type receives this information. The set flow control type is set and stored for each call, and the flow control type is an end-to-end (E-
A window size control method characterized in that the received packet is passed as it is on the E) type communication path, while the transfer packet processing is performed with the window size set for the link in the link-by-link (L × L) type.