JPH0468733A - Cell multiplex system - Google Patents

Abstract

PURPOSE:To improve the economy of a 1st first-in first-out storage means by extracting identification information stored in a 2nd first-in first-out storage means in the first-come order and sending a cell stored in the first-in first-out storage means represented by the identification information to an outgoing highway in the first-come order. CONSTITUTION:The order of the arrival of each cell Xik reached in incoming highways 4-1-4-4 is stored in a queue buffer 5-i. Then the order of the arrival among the incoming highways 4-1-4-4 is identified by a queue number ci stored in a queue buffer 62. Then the cell is extracted sequentially from the queue buffer 5-i according to the order of the queue number ci and sent to an outgoing highway 8, then each cell is sent in the first-come order. Since the queue number ci is made up of at minimum 2-bit when four lines are used for the incoming highways 4, a multiplexer circuit 61 is sufficiently realized at an operating speed almost similar to the speed of the incoming highways 4 and the outgoing highways 8.

Description

[Detailed Description of the Invention] [Summary] - A cell multiplexing system in an asynchronous transfer mode transmission network, which enables each cell arriving from a plurality of input highways to be sent to an output highway on a first-come, first-served basis, and the speed of the input highway and the output highway, A first first-in, first-out storage means that stores cells arriving from each input highway on a first-come, first-served basis in response to multiple input highways, with the aim of realizing a cell multiplexing system that requires similar operating speeds. and identification information sending means for sending identification information of the first first-in, first-out storage means each time a cell is accumulated in the first-in, first-out storage means of each library. a second first-in, first-out storage means for accumulating each piece of identification information sent from the identification information sending means on a first-come, first-served basis; Output determining means is provided for extracting one cell stored in the first first-in, first-out storing means indicated by the extracted identification information in order of destination and sending it to an output highway provided in common to each human-powered highway. Configure.

[Industrial application field]

The present invention relates to a cell multiplexing method in an asynchronous transfer mode transmission network.

[Conventional technology]

FIG. 4 is a diagram showing an example of a cell switch to which the present invention is applied, and FIG. 5 is a diagram showing an example of a cell to which the present invention is applied.

Asynchronous transfer mode
answerMode: ATM) In the transmission network, the information to be transmitted, such as voice, image, data, etc., with different characteristics is divided into blocks of fixed length, and a header indicating the transmission destination etc. is added to each block. Construct a cell as shown in the figure.

In FIG. 5, the information section I has a length of 48 octets.
A header part H having a length of 5 octets is added to
It makes up a cell.

The cell switch shown in FIG. 4 has nine input highways 1 [individual input highways are denoted by 1-i, i (=
1 to n) are referred to as input highway numbers] and nine output highways 2 [individual output highways are designated as 1-j, and j (=1 to n) are referred to as input highway numbers].
are coupled in a matrix through switch elements 3 (individual switch elements are indicated by 3-ij).

Cells as shown in FIG. 5 arrive in time series from each input highway 1-i and are transmitted to n switch elements 3-11 to 3-in, respectively.

Each switch element 3-11 to 3jn analyzes the header part H of each cell arriving from the input highway 1-i, and the switch element 3-ij located at the intersection with the output highway 2j corresponding to the transmission destination, The corresponding cell is extracted from the input highway 1 and transmitted to the corresponding output highway 2-j.

As a result, cells arriving from multi-input highways 1 to 1 to 1-n are connected to switch elements 3-1j to 3-n, respectively.
After being statistically distributed 1/n to each output highway 2-j, the cells are statistically multiplexed and transmitted to each output highway 2-j, so the cell transmission efficiency of each output highway 2-j is It becomes equal to the transmission efficiency of input highway 1-i.

Next, FIG. 6 is a diagram showing an example of a conventional cell multiplex circuit, and FIG. 7 is a diagram showing an example of the time chart in FIG. 6.

The cell multiplexing circuit shown in FIG. 6 multiplexes cells arriving from four (n=4) input highways 4 onto - output highways 8 and outputs the cells.

That is, the input highway 4 is the switch element 3 in FIG.
-1j to 3-4j, and output highway 8 corresponds to output highway 2-j in FIG.

Further, a queue buffer 5 is provided corresponding to each input highway 4, and a competition circuit 6 is provided in common to each input highway 4.

In Figures 6 and 7, each input highway 4-
1' to time th' (however, = o, 1.2,
...) [Fig. 7 (a)
)].

Cells Xik arriving from each input highway 4-i are accumulated in the corresponding queue buffer 5-i on a first-come, first-served basis [FIG. 7(b)]. Note that square brackets (for example, [X+O]) in FIG. 7(b) indicate that storage is in progress.

Each queue buffer □A5-i in which cells Xik are accumulated is
Each output request signal a is output and transmitted to the competition circuit 6.

The competition circuit 6 repeatedly selects the output request signals a transmitted from each queue buffer 5-i in a certain order (for example, in ascending order of i), and selects the output permission signals b, corresponding to the selected output request signals a4. and output the corresponding queue buffer 5-
i [Figure 7(C)].

The queue buffer 5-i, which has received the output permission signal b, extracts the stored cells Xik one by one on a first-come, first-served basis and sends them out to the output highway 8 via the output bus flow (see FIG. 7).
d)]. Note that the parentheses (for example, (X
+o) ) indicates extraction in progress.

[Problem to be solved by the invention]

As is clear from the above description, in a conventional cell multiplexing circuit, the competition circuit 6 repeatedly selects the queue buffers 5-i that are outputting the output request signal a, in a fixed order, and transmits the output permission signal S. i.e. each queue buffer 5
-1 to 5-4 are given equal extraction opportunities, so cells Xi arriving from name input highways 4-1 to 4-4
If we focus on each input highway 4-i, cell Xik is sent to output highway 8 on a first-come, first-served basis, but between input highways 4-1 to 4-4, cell Xik that arrives first is not necessarily sent to output highway 8 first. It does not necessarily mean that it will be sent,
For example, in FIG. 7(d), cells C1 and Dl arrive at time tl, and cell A2 arrives at time t2.
is transmitted after cell B3, which arrives at time t3.

Therefore, the delay time from when each cell Xik arrives from the input highway 4-i until it is sent to the output highway 8 is non-uniform for each input highway 4-i. Not only will it be longer,
On the input highway 4-i where cells arrive frequently, cells X waiting to be sent out in the corresponding queue buffer 5-i
There was a problem in that ik increased and eventually exceeded the cell storage capacity of the queue buffer 5-i, resulting in arriving cells being discarded.

In order to solve this problem, a cell multiplex circuit as shown in FIG. 8 has been considered.

FIG. 8 is a diagram showing another example of a conventional cell multiplexing circuit, and FIG. 9 is a diagram showing an example of a time chart in FIG. 8.

In FIGS. 8 and 9, each cell XIO to
4° is time-division multiplexed by the time-division multiplexing circuit 9 up to time t [FIG. 9(c)] in a certain order (for example, in ascending order of the input highway number i). The data is sent to the multiplex highway 10 and accumulated in the queue buffer 11 [FIG. 9(C)].

Similarly, each input highway 4-1.4-
3 and 4-4 are received and stored in the queue buffer 11 up to time t2, and the cells Xll, X31 and X41 arriving from the input highway 4-
Cells X+Z arriving at input highways 4-1, 4-2 and 4-3 are received and accumulated in queue buffer 11 up to time t3, and cells X+Z arriving at input highways 4-1, 4-2 and 4-3 at time t2 are X33 is received and accumulated in the queue buffer 11 up to time t3.

The queue buffer 11 stores each accumulated cell X+o, XZ
O, X30, X40, Xll, X 3+, X ,,
Let X,,,X,3,XZZ,X'12 be at each time point tl,・
... Extract one piece to tll on a first-come, first-served basis and send it to output highway 8.

In the cell multiplex circuit illustrated in FIG. 8, each cell arriving from the input highways 4-1 to 1-4 is accumulated in the queue buffer 11 on a first-come, first-served basis. The delay times for each 4-4 are averaged,
In addition, the queue buffer 11 is connected to input highways 4-1 to 4-4.
-4, it is used more efficiently than the total storage capacity of the queue buffers 5-1 to 5-4 shown in FIG. i k , the input highways 4-1 to 4-4 have an equal chance of becoming full and being discarded.

However, the time division multiplexing circuit 9 must time division multiplex the four cells X1°, X2°, X30 and This problem makes it difficult to realize a cell multiplex circuit that targets the input highway 4 and output highway 8, which are originally high-speed, because the input highway 4 and output highway 8 need to operate at four times the speed of the input highway 4 and the output highway 8. was there.

The present invention enables cells arriving from a plurality of input highways to be sent to an output highway on a first-come, first-served basis, and to realize a cell multiplexing system that requires an operation speed comparable to the speed of the input highway and the output highway. With the goal.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention.

In FIG. 1, 4 is a plurality of input highways, and 8 is a single output highway.

100 is a first first-in first-out storage means provided corresponding to each input highway 4 according to the present invention.

200 is identification information sending means provided corresponding to each input highway 4 according to the present invention.

Reference numeral 300 denotes a second first-in first-out storage means provided in common for each input highway 4 according to the present invention.

Reference numeral 400 denotes an output determining means provided in common for each input highway 4 according to the present invention.

[Effect]

The first first-in, first-out storage means 100 stores cells arriving from the corresponding input highway 4 in a first-come, first-served order.

The identification information sending means 200 sends the identification information of the first first-in, first-out storing means 100 each time a cell is stored in the corresponding first first-in, first-out storing means 100.

The second first-in, first-out storage means 300 stores each identification information sent from each identification information sending means 200 on a first-come, first-served basis.

The output determining means 400 is the second first-in first-out accumulating means 300
One cell stored in the first first-in, first-out storage means 100 indicated by the extracted identification information is extracted in order of destination and sent to the output highway 8.

Since the amount of identification information sent out from each identification information sending means 200 is much smaller than that of a cell, the second first-in first-out storage means 300 has the same amount as each first first-in first-out storage means 100. It is possible to sufficiently accumulate the identification information sent from each identification information sending means 200 at the operating speed of .

Therefore, each cell arriving from each input highway is extracted from each first first-in, first-out storage means on a first-come, first-served basis and sent to the output highway, so that the serviceability for each input highway is equalized, and the first Since the usage of the first-in, first-out storage means is also equalized, the first first-in, first-out storage means can be realized economically, and at the same operating speed as the input highway and the output highway. Therefore, it is suitable for large scale.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing a cell multiplexing circuit according to an embodiment of the present invention, and FIG. 3 is a diagram showing an example of a time chart in FIG. 2. Note that the same reference numerals indicate the same objects throughout the figures.

In FIG. 2 as well, it is assumed that cells arriving from four input highways 4 are multiplexed onto - output highways 8 and sent out, and a queue buffer is used as the first first-in, first-out storage means 100 in FIG. 5 is also the queue number sending circuit 12 as the identification information sending means 200 in FIG.
are provided corresponding to each input highway 4, respectively,
Furthermore, as the second first-in first-out storage means 300 and output determining means 400 in FIG. It is provided.

In FIGS. 2 and 3, from input highway 4-1, cell X. , Xll, X12 and X13 arrive at time io, L+, Lz and t3, respectively [
FIG. 3(a) L queue buffer 5-1 has cells x1°,
o, Xl□ and Xll are accumulated on a first-come, first-served basis [Figure 3 (
b)].

Each cell X2°, XZS, X, arriving from other input highways 4-2.4-3 and 4-4. ,X31%X
33, X4°, and X41 are also accumulated in the corresponding queue buffers 5-2, 5-3, and 5-4 on a first-come, first-served basis [FIGS. 3(a) and 3].

On the other hand, the queue number sending circuit 12-1 provided corresponding to the input highway 4-1 stores the cells X1°, Xll, XIx, and X13 arriving from the input highway 4-1 at times t0, 1, A queue number C+ (for example, "1") for identifying the queue buffer 5-1 is output at t2 and t3, and the multiplex circuit 6 in the competition circuit 6
1.

Similarly, the queue number sending circuit 12-2 provided corresponding to the input highway 4-2 is also connected to the input highway 4-2.
The queue number sending circuit 12 which is provided corresponding to the input highway 4-3 outputs the queue number Cz (-"2") at the time points t0 and t3 when cells X2° and X23 arrive from the input highway 4-3. -3 also input highway 4
-3 to cell X 30. X 31 and X 33 At the arrival times Lo, L+ and t, queue number C3
'3J) respectively, and input highway 4-4.
A queue number sending circuit 12-4 provided corresponding to
Also, from input highway 4-4, cell X4° and Xat
Queue number c4 (=
'4') and transmit them to the multiplex circuit 61, respectively.

The multiplex circuit 61 includes each queue number sending circuit 121 to 12.
The queue numbers C1 to C4 transmitted from -4 are time-division multiplexed at each time point to to t3, and stored in the queue buffer 62 on a first-come, first-served basis [FIG. 3(C)].

Note that cue numbers c to c4 can be configured with at least 2 pins in order to identify the four queue buffers 5-1 to 5-4, so the operating speed of the multiplex circuit 61 is the same as that of the input highway 4 and output highway 4. A speed similar to that of Highway 8 is sufficient.

The queue buffer 62 first extracts the accumulated queue number c+ (='l') at time tI and transmits it to the conversion circuit 63 [FIG. 3(d)].

The conversion circuit 63 converts the queue number CI (=“lJ)” transmitted from the queue buffer 62 into the queue number CI (=
'lJ) is converted into an output permission signal b1 for the queue buffer 51 identified by the signal b1, and transmitted to the queue buffer 5-1 [FIG. 3(e)].

When the queue buffer 5-1 receives the output permission signal b1 from the conversion circuit 63, it first selects the stored cells X,. is extracted and sent to the output highway 8 via the output bus flow [Figure 3].

Similarly, the queue buffer 62 is stored from time 11 to tll.
To\Q1 number C2\C3sC4sCIsC3, C4,
CI, C1, % Cz and C1 are extracted on a first-come, first-served basis and transmitted to the conversion circuit 63 [FIG. 3(d)], and the conversion circuit 63
is each transmitted queue number Cz, C3+, C41C1
% C3% C4% CI X CI ＼
Output permission signals b2, bl, b corresponding to C2 and C3
4, bl, b8, b4, b3, bl, b2 and s, respectively corresponding queue buffers 5-2.5-
3.5-4.5-1.5-3.5-4.5-1.5-1
．． 5-2 and 5-3 [Fig. 3(e) L output permission signals bz, bzb4, bt, ba, ba, bt]
, bt , bt and b3 each queue buffer 5-2.5-3.5-4.5-1.5-3.5-4
．． 5-1.5-1.5-2 and 5-3 are cells Xzo, X36, x4°, X8, X31, X als, respectively
XIx, X13, L3 and χ,3 are sequentially extracted and sent out from the output highway 8 via the output bus flow [FIG. 3(f)].

As is clear from the above description, according to this embodiment, each cell x11 arriving from the input highways 4-1 to 4-4
．． The arrival order within each input highway 4-i is maintained by the queue buffer 5-i, and the arrival order between the input highways 4-1 to 4-4 is identified by the queue number C8 stored in the queue buffer 62. and cue number C8
Since the cells are sequentially extracted from the queue buffer 5-i and sent to the output highway 8 in accordance with the order of , each cell is sent out on a first-come, first-served basis.

In addition, since the queue number C'i is composed of at least 2 bits when there are four input highways 4, the multiplex circuit 61 can be sufficiently realized at an operating speed comparable to that of the input highways 4 and output highways 8. It becomes possible.

Note that FIGS. 2 and 3 are only one embodiment of the present invention, and the arrival status of cells from each of the input highways 4-1 to 4-4 is not limited to what is shown in the figures. Although many other modifications may be considered, the effects of the present invention remain the same in any case. Further, the number of input highways 4 is not limited to four, and many other modifications may be considered, but the effects of the present invention remain the same in any case.

Furthermore, it goes without saying that the application of the cell multiplex circuit is not limited to the illustrated cell switch.

〔Effect of the invention〕

As described above, according to the present invention, each cell arriving from each input highway is extracted from the multi-tube first-in, first-out storage means on a first-come, first-served basis and sent to the output highway, so that the serviceability for each input highway is also equalized. In addition, since the usage of the first FIFO storage means is equalized, it is possible to economically realize the first FIFO storage means, while operating at the same level as the input highway and the output highway. Since it can be realized quickly, it is suitable for large scale.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram showing a cell multiplexing circuit according to an embodiment of the present invention, FIG. 3 is a diagram showing an example of the time chart in FIG. 2, and FIG. FIG. 5 is a diagram showing an example of a cell switch to which the present invention applies, FIG. 6 is a diagram showing an example of a conventional cell multiplex circuit, and FIG. 7 is a diagram showing an example of a cell to which the present invention applies. 6 is a diagram showing an example of the time chart, FIG. 8 is a diagram showing another example of a conventional cell multiplexing circuit, and FIG. 9 is a diagram showing an example of the time chart in FIG. 8. In the figure, 1 and 4 are input highways, 2 and 8
is the output highway, 3 is the switch element, 5.11 and 62 are the Cuban sofas, 6 is the competition circuit, 7 is the output bus,
9 is a time division multiplex circuit, 10 is a multiplex highway, 12 is a queue number sending circuit, 61 is a multiplex circuit, 63 is a variable circuit,
100 is the first first-in-first-out storage means, 200 is the identification information sending means, 300 is the second first-in-first-out storage means, and 400 is the output failure BRf) welfare mouth. Route 12 ro sho old, fshi 4 equipmentaF4iQt #$Σ2teJ] U1 nil 75 old b conventional 2PlroErutasankou road station b record 4ff/if/nchinshinro y valley Station 8 Record 1b Record 1; Okero Time 4 Yard 77 Old No. 8N difference;

Claims (1)

[Scope of Claims] First first-in, first-out storage means (100) for storing cells arriving from each input highway (4) on a first-come, first-served basis in correspondence with a plurality of input highways (4); and identification information sending means (200) for sending identification information of the first first-in, first-out storing means (100) each time a cell is stored in the first first-in, first-out storing means (100), Common to each input highway (4), a second first-in, first-out storage means (300) that stores each piece of identification information sent out from each of the identification information sending means (200) on a first-come, first-served basis; The identification information stored in the output storage means (300) is extracted on a first-come, first-served basis, and one cell stored in the first first-in, first-out storage means (100) indicated by the extracted identification information is sent to the destination. The output highways (4) provided in common with the respective input highways (4) are
8) A cell multiplexing system characterized in that it is provided with an output determining means (400) for sending data to the cell.