JP2805992B2 - Packet switch and its connection control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet switch used in a packet switch and the like, and a connection control device therefor.

FIG. 6 shows a configuration of a conventional packet switch. In FIG. 6, reference numerals 601 to 60n denote input lines, which are connected to packet output destination information separating units 621 to 62n via packet receiving units 611 to 61n, respectively. The packet output destination information separating units 621 to 62n have two outputs, and one packet output terminal 62i1 (i = 1 to n) is connected to the switch network 63.
Are connected to the packet input terminals 6311 to 631n. The other output destination information output terminals 62i2 (i = 1 to n) are connected to output destination information input terminals 6411 to 641n of the switch network control unit 64. The switch network control output terminals 6421 to 642m of the switch network control unit 64 are connected to the control input terminals 6321 to 632m of the switch network 63, respectively. The switch network 63
Are connected to the switch network monitoring input terminals 6431 to 643m and the output buffer units 651 to 65m of the switch network control unit 64, respectively. Outputs of the buffer units 651 to 65m are connected to output lines 671 to 67m via packet transmission units 661 to 66m.

FIG. 7 shows the configuration of the switch network 63. In FIG. 7, reference numerals 6341 to 634m denote multiplexers, signal input terminals are connected to the packet input terminals 6311 to 631n, connection selection terminals are connected to the control input terminals 6321 to 632m, and output terminals are the packet output terminals 6331. ~ 633m is connected.

Next, the operation of the above conventional example will be described. Input line 60
When a packet is input to i, the packet is received by the packet receiving unit 61i and input to the packet output destination information separating unit 62i. The packet input to the packet output destination information separating unit 62i is buffered and the output destination information is separated at the same time and input to the switch network control unit 64. Switch network controller 64
Obtains an output line 67j to output a packet from the input output destination information, and obtains a packet output terminal 6
33j monitors whether a packet is being output. When not outputting, the selection signal is output to the selection connection terminal of the multiplexer 634j, and the packet input terminal 631i and the packet output terminal 633j are connected. After being connected, the packet buffered by the packet output destination information separating unit 62i is input to the packet input terminal 631i, and is output from the packet transmitting unit 66j to the output line 67j via the packet output terminal 633j and the output buffer 65j. Sent to.

Thus, even in the above-described conventional packet switch, when a packet is input, the packet can be output to an output line corresponding to output destination information in the packet.

However, in the conventional packet switch described above, since the switch network can connect only one input line to one output buffer at a time, a packet addressed to the same output line can be input simultaneously by a plurality of input lines. In this case, it takes time to complete the exchange of all the packets, and the buffer of the packet output destination information separating unit overflows, so that there is a problem that all the packets cannot be exchanged.

The present invention solves such a conventional problem and provides an excellent packet switch capable of exchanging all input packets and a connection control device therefor.

Means for Solving the Problems The packet switch of the present invention connects n input lines and m output lines, and in particular, connects n input lines and (m × r) intermediate output lines. The switch network to be connected and the intermediate output lines are r lines for each output line,
Output means for connecting to an output line via an output buffer;
A connection control unit for controlling the connection between the input line and the intermediate output line in the switch network is provided for each input line, and the connection control unit for each input line is ring-connected to the connection control unit for the other input lines, The connection control unit outputs the reservation information of the intermediate output line to the connection control unit of the lower ring, the connection control unit of the lower ring refers to the reservation information input from the connection control unit of the upper ring, the input, Reserve an unreserved intermediate output line from among r intermediate output lines that can be connected to an output line indicated by a packet input from the line,
After that, the control unit updates the reservation information and outputs the updated information to the connection control unit below the ring, and after the reservation information makes a round on the ring, includes a reserved intermediate output line and connection control means for controlling connection of the input line. It is characterized by:

Further, the connection control device of the packet switch of the present invention,
A switch network in a packet switch is controlled, and the switch network has n input lines and (m × r) intermediate output lines, and connects n input lines and (m × r) intermediate output lines. It is provided for each input line,
A connection control unit for controlling connection between an input line and an intermediate output line in the switch network, wherein a connection control unit for each input line is ring-connected to a connection control unit for another input line; Outputs the reservation information of the intermediate output line to the lower connection control unit of the ring, and the lower connection control unit of the ring refers to the reservation information inputted from the upper connection control unit of the ring, and is inputted from the input line. The unreserved intermediate output line is reserved from among the r intermediate output lines connectable to the output line indicated by the packet, and the reservation information is updated and output to the lower connection control unit of the ring. After the reservation information makes one round, the connection between the reserved intermediate output line and the input line is controlled.

Operation The present invention has the following operation with the above configuration. That is, since r intermediate output lines and output buffers are provided for each output line, up to r packets arriving at the same time and destined for the same output line can be written into the output buffer, and at the same time up to r identical output lines can be output. Packet switching for the line can be performed.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention.
In FIG. 1, reference numerals 101 to 10n denote input lines, which are respectively connected to packet output destination information separating units 121 to 12n via packet receiving units 111 to 11n. The packet output destination information separating units 121 to 12n have two outputs, and one packet output terminal 12i1 (i = 1 to n) is connected to the packet input terminals 211 to 21n of the switch network 2. The other output destination information output terminals 12i2 (i = 1 to n) are connected to the output destination information input terminals 3i1 (i = 1 to n) of the connection control units 31 to 3n, respectively. The connection control units 31 to 3n each have three output terminals and one input terminal. The connection control units 31 to 3n
Switch control output terminal 3i2 (i = 1 to
n) is a switch control input terminal 221-2 to 2 of the switch network 2.
Connected to 2n. Output enable terminal which is another output terminal
3i3 (i = 1 to n) are packet output destination information separation units 121 to 12
n output control input terminals 12i3 (i = 1 to n). The reservation information output terminals 313 to 3n4, which are other output terminals,
The connection control units 31 to 41 through the pseudo connection control units 41 to 4n, respectively.
It is connected to 3n reservation information input terminals 315 to 3n5 as shown in FIG.

Reference numeral 5 denotes a congestion control unit, which is a reservation control output of the congestion control unit 5.
Reference numeral 51 is connected to the pseudo connection control units 41 to 4n.

The congestion detection input 52 which is an input of the congestion control unit 5 includes:
Intermediate output buffer units 1411 to 141r, 1421 to 142r, ..., 14m1-1
A waiting cell number output of 4 mr (hereinafter simply referred to as 1411 to 14 mr) is input. The input terminals of the intermediate output buffer units 1411 to 14mr have intermediate output lines 1311 to 131r, 1321 to 132r,.
The packet outputs 2311 to 231r and 2321 to 2 of the switch network 2 via 3m1 to 13mr (hereinafter simply referred to as 1311 to 13mr)
, 23m1 to 23mr (hereinafter simply referred to as 2311 to 23mr). The intermediate output buffer unit 1411-
The other terminal of 14mr is input to multiplexers 151 to 15m. The outputs of the multiplexers 151 to 15m are connected to output lines 171 to 17m via packet transmission units 161-1 to 16m.

FIG. 2 is a diagram showing a specific example of the switch network 2 (i = 1 to n) shown in FIG. In FIG. 2, reference numerals 24111 to 24 nmr denote multiplexers, which are connected as shown in FIG.

FIG. 3 is a diagram showing a specific example of the connection control unit 3i (i = 1 to n) shown in FIG. In FIG. 3, reference numeral 3i6 denotes an unreserved detection unit, 3i7 denotes a reservation unit, 3i8 denotes a switch control signal generation unit, 3i9 denotes an initial reservation detection unit, 3i10 denotes an unreserved information generation unit, 3i
i11 is a two-input one-output multiplexer, 3i12 is a timing generator, 3i13 is an intermediate output line number signal line, and 3i14 is a reservation permission signal line, which are connected as shown in the figure.

FIG. 4 shows the configuration of the pseudo connection control unit 4i (i =
1-n). In FIG. 4, reference numeral 4i1 denotes a prohibited intermediate line input terminal, 4i2 denotes a reservation information input terminal, 4i4 denotes a reservation detector, 4i
Reference numeral 5 denotes a pseudo reservation unit, and reference numeral 4i6 denotes a two-input one-output multiplexer, which are connected as shown in the figure.

FIG. 5 shows the configuration of the congestion control unit 5. In FIG. 5, reference numeral 52 denotes a congestion detection input, and a congestion determination unit 53i (i
= 1 to n). Congestion determination unit 53i (i = 1
To n) are input to the intermediate output line limiting unit 54.
The reservation control output terminal 51 of the intermediate output line limiting unit 54 is a use-prohibited intermediate line input terminal of the pseudo connection control unit 4i (i = 1 to n).
4i1 (i = 1 to n).

Next, the packet output destination information separation unit in the above embodiment
12i, switch network 2, congestion control unit 5, pseudo connection control unit 4i
Each operation will be described.

First, the operation of the packet output destination information separating unit 12i will be described (i = 1 to n). The packet input to the input line 10i is received by the packet receiving unit 11i, and is input to the packet output destination information separating unit 12i. When the packet is input from the packet receiving unit 11i, the packet output destination information separating unit 12i writes the packet into an internal buffer, and at the same time, analyzes the header of the packet to determine the output line number of the output destination. Then, the output line number of the output destination of the first packet in the internal buffer is output from the output destination information output terminal 12i2, and the connection control unit 3i
To the output destination information input terminal 3i1. When an output permission signal is input to the output control input terminal 12i3, the first packet in the buffer is read out, output from the packet output terminal 12i1, and input to the packet input terminal 21i of the switch network 2.

Next, the operation of the switch network 2 will be described. The internal multiplexers 24111 to 24 nmr connect the upper input terminal and the output terminal shown in FIG. 2 in a default state. When the switch control signal is input to the switch control input terminal 22i, the designated one of the multiplexers 24i11 to 24imr is switched, and the lower input terminal is connected to the output terminal.

Next, the operation of the congestion control unit 5 will be described. Congestion control unit 5
Monitors the number of output waiting packets for each output line and performs control to keep the number of output waiting packets equal to or less than a set value. That is, the congestion control unit 5 includes the intermediate output buffer units 1411 to 1411
The number of output waiting packets output from mr is received at the congestion detection input terminal 52, and the number of output waiting packets received is
It is input to the congestion determination unit 53i. The congestion determination unit 53i adds the input number of output waiting packets and outputs
Calculate the total number of output waiting packets to 17i. Congestion determination unit 5
3i determines that congestion is present when the total number of output waiting packets exceeds the set value, and determines at one time the intermediate output buffer 14i1 according to the size of the total number of output waiting packets to the output line 17i.
The number of packets permitted to be written to ir14ir (the number of packets permitted to be written) is obtained and output to the intermediate output line limiting unit 54. The intermediate output line limiting unit 54 subtracts the number of write-permitted packets from the number r of intermediate output lines for each output line, obtains the number of use-prohibited intermediate lines for each output line, and sets the pseudo connection control units 41 to 4n.
Output to

Next, the operation of the pseudo connection control unit 4i will be described (i = 1 to
n). The reservation detector 4i4 analyzes the reservation information input to the reservation information input terminal 4i2, and only when one of the intermediate output lines 1311 to 13mr is reserved, the multiplexer
Notify 4i6 of switching permission. On the other hand, the pseudo reservation unit 4i5 analyzes the input reservation information and reserves intermediate lines by the number of use prohibited intermediate lines for each output line input from the congestion control unit 5 to the use prohibited intermediate line input terminal 4i1. The reservation information is updated and input to the multiplexer 4i6. The multiplexer 4i6 outputs the reservation information input to the reservation information input terminal 4i2 in the default state from the reservation information output terminal 4i3. Only if you ’ve been notified of the switch,
The reservation information updated in the pseudo reservation unit 4i5 is output from the reservation information output terminal 4i3.

Next, the overall operation of the above embodiment will be described. First, the overall operation when the output lines 171 to 17m are not congested will be described.

Since there is no congestion, in the pseudo connection control unit 4i,
Since the intermediate line is not reserved, the reservation information input to the pseudo connection control unit 4i is output without being updated.
In the previous packet exchange, the connection control unit 3i detects in the first reservation detection unit 3i9 that the reservation was made first,
Switching the multiplexer 3i11, the unreserved information generation unit 3i10
The reservation information indicating that all of the intermediate output lines 1311 to 13mr are not reserved is output to the reservation information output terminal 3i4.

The connection control unit 3p (p = i + 1) at the lower level of the ring converts the reservation information input to the reservation information input 3p5 into the unreserved detection unit 3p6.
When the intermediate output lines 1311 to 13mr are all unreserved, the first reservation detecting unit 3p9 is notified. Meanwhile, the reservation unit 3
When the output line number is input to the output destination information input terminal 3p1, p7 is an intermediate output line 1311 to 13mr that can analyze the reservation information in the reservation unit 3p7 and connect to the desired output line 171 to 17m. Find the number of the unreserved one,
The reservation permission signal is output from the reservation permission signal line 3i14, and the switch control signal generator 3p8 is output from the intermediate output line number signal line 3p13.
Output to At the same time, the reservation information is updated and output from the reservation information output terminal 3p4. However, desired output line 1
Intermediate output line 1311-13m that can be connected to 71-17m
If r is already reserved, a reservation non-permission signal is output from the reservation permission signal line 3i14, and the reservation information is directly output from the reservation information output terminal 3p4.

By performing the above operation by each connection control unit 3p, the reservation of the intermediate output lines 1311 to 13mr is performed, and the reservation information goes around the ring. In each connection control unit 3p, the timing generation unit 3p12 operates in synchronization with the timing generation units of the other connection control units, and generates timing at which the reservation information completes one cycle on the ring. At this timing, the control signal for connecting to the intermediate output line number output from the switch control signal generator 3p8 is a switch control output terminal.
The signal is output via 3p2, and among the multiplexers 24111 to 24 nmr in the switch network 2, the multiplexer corresponding to the desired intermediate output line is switched, and the connection in the switch network 2 is performed. At the same time, an output permission signal is input from the output permission terminal 3p3 to the packet output destination information separating unit 12p, and the buffered packet is transferred to the intermediate output line 1311 via the multiplexers 2411 to 24nmr in the switch network 2.
Sent to ~ 13mr. Further, at the above timing, the initial reservation detection unit 3p9 detects that the reservation has been made first since the unreserved information is detected by the unreserved detection unit 3p6 and the reservation is permitted by the reservation unit 3p7. Thereafter, the above operation is repeated.

On the other hand, the packets sent out on the intermediate output lines 1311 to 13mr are buffered in the intermediate output buffers 1411 to 14mr, and the multiplexers 151 to 15m and the packet transmission unit 161
Are sent to output lines 171 to 17m via .about.16m.

Next, the overall operation when the output lines 171 to 17m are congested in the above embodiment will be described.

The operation of starting the reservation information when the output lines 171 to 17m are congested, and the operation of transmitting a packet onto the intermediate output line after the reservation information has completed one cycle are the same as those when the output line is not congested. .

However, in one round of the reservation information, the pseudo connection control unit 3i, which analyzes the input reservation information and detects that only one intermediate output line is reserved, outputs the intermediate connection line for each output line input from the congestion control unit 5. The intermediate output lines 1311 to 13mr are reserved for the number of use-prohibited intermediate output lines. The reserved intermediate output lines 1311 to 13mr are not used for packet output. That is, as soon as the connection control unit 3i first reserves the intermediate output line on the ring, the pseudo connection control unit 4i reserves the intermediate output lines 1311 to 13mr that are not actually used. Use can be restricted.

Thus, as shown in the above embodiment, r
The provision of intermediate output lines allows the exchange of up to r packets destined for the same output line at a time, even if a plurality of packets destined for the same output line are input at one time. Without overflow
Can exchange packets.

In addition, since the input line that has reserved the intermediate output line first has the means for making the last reservation in the next intermediate output line reservation, the input line and the output line can be connected without being biased to a specific input line.

Further, since means for variably limiting the number of intermediate output lines that can be reserved is provided according to the number of packets waiting to be output to the output line, it is possible to control the restriction of packet exchange according to the congestion state of the output line.

As described above, according to the above embodiment, since r intermediate output lines are provided for each output line, even if a plurality of packets destined for the same line are input at a time, up to r same output lines can be simultaneously input. It is possible to exchange packets destined for the packet without exchanging a buffer on the input line due to waiting for exchange.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a packet switch according to an embodiment of the present invention, FIG. 2 is a block diagram showing a specific example of the switch network shown in FIG. 1, and FIG. 3 is a block diagram showing a connection control unit shown in FIG. FIG. 4 is a block diagram showing a specific example of the pseudo connection control unit shown in FIG. 1, FIG. 5 is a block diagram showing a specific example of the congestion control unit shown in FIG. 1, and FIG. FIG. 7 is a block diagram showing a specific example of the switch network shown in FIG. 2 switch network, 5 congestion control unit, 31 to 3n connection control unit, 41 to 4n pseudo connection control unit, 54 intermediate output line limiting unit, 101 to 10n input line, 111 ... 11n ... Packet receiving unit, 121-12n ... Packet output destination information separating unit, 15
1 to 15 m multiplexer, 161 to 16 m packet transmission unit, 171 to 17 m output line, 3i6 (i = 1 to n) unreserved detection unit, 3i7 (i = 1 to n) reserved Part, 3i8 (i =
1 to n) switch control signal generator, 3i9 (i = 1 to
n)... first reservation detecting section, 3i10 (i = 1 to n)... unreserved information generating section, 3i11 (i = 1 to n).
3i12 (i = 1 to n): timing generation unit, 4i4 (i =
1 to n): reservation detection unit, 4i5 (i = 1 to n): pseudo reservation unit, 4i6 (i = 1 to n): multiplexer, 531 to
53m: congestion determination unit, 1311 to 13mr: intermediate output line, 141
1 to 14mr: intermediate output buffer, 24111 to 24nmr: multiplexer.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04L 12/28 H04L 12/56

Claims (5)

(57) [Claims] 1. A packet switch for connecting n input lines and m output lines, comprising: a switch network connecting n input lines and (m × r) intermediate output lines; Output means for collecting r lines for each output line and connecting to the output line via an output buffer, and a connection control unit for controlling the connection between the input line and the intermediate output line in the switch network for each input line. The connection control unit of each input line is ring-connected to the connection control unit of the other input line, the upper connection control unit of the ring outputs the reservation information of the intermediate output line to the lower connection control unit of the ring, The lower connection control unit of the ring refers to the reservation information input from the upper connection control unit of the ring and selects one of the r intermediate output lines that can be connected to the output line indicated by the packet input from the input line. Reservation The intermediate output line reserves,
After that, the control unit updates the reservation information and outputs the updated information to the connection control unit below the ring, and after the reservation information makes a round on the ring, includes a reserved intermediate output line and connection control means for controlling connection of the input line. A bucket switch, characterized in that: 2. The connection control unit connected to the ring recognizes that the reservation information has first reserved the intermediate output line when the reservation information makes a round of the ring, and has performed the reservation of the intermediate output line first. 2. The packet switch according to claim 1, wherein the connection control unit located below the ring of the connection control unit that recognizes the start of the next reservation information. 3. The number of output waiting packets stored in an output buffer in the output means is counted, and a part of the intermediate output line is disabled according to the number of output waiting packets for each output line. Means for rewriting the reservation information transmitted on the ring between the connection control devices, when the output line is congested, the connection to the intermediate output line connected to the congested output line is provided. 2. The packet switch according to claim 1, wherein the packet switch is restricted to avoid congestion on the output line. 4. A switch network in a packet switch, wherein the switch network has n input lines and (m × r) intermediate output lines, and has n input lines and (m × r) intermediate output lines. In the connection control device for controlling the connection of the intermediate output line, the connection control unit is provided for each input line and configured to control the connection between the input line and the intermediate output line in the switch network. The connection control unit of the other input line is ring-connected, the connection control unit of the upper ring outputs the reservation information of the intermediate output line to the connection control unit of the lower ring, and the connection control unit of the lower ring is connected to the upper ring. With reference to the reservation information input from the connection control unit, an unreserved intermediate output line is reserved from among r intermediate output lines that can be connected to the output line indicated by the packet input from the input line. A connection control of a packet switch, which updates the reservation information and outputs it to a connection control unit below the ring, and after the reservation information loops on the ring, controls connection between the reserved intermediate output line and the input line. apparatus. 5. The connection control unit connected to the ring recognizes that the reservation information has first reserved the intermediate output line when the reservation information makes a round of the ring, and has first reserved the intermediate output line. 5. The connection control device for a packet switch according to claim 4, wherein the connection control unit below the ring of the connection control unit that recognizes the start of the next reservation information starts.