JPH10233804A - Packet data transfer controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the packet data transfer controller that improves a communication efficiency of packet data converted to cells and reduces the cost. SOLUTION: An entry number registered to either of 1st and 2nd entry number reference tables ERT1, ERT2 is referenced and every time a cell of each entry registered in an entry control table ECT is transferred in time division, the entry number of the entry number whose transfer is not finished is registered again to the 2nd or 1st entry number reference table ERT2, ERT1, and the entry number of the entry whose transfer is finished is registered in an empty entry number management table EMT. Every time one cell is transferred in time division among cell of all the entries registered in the entry control table ECT, the 1st or 2nd entry number reference table ERT1 or ERT2 is alternately referenced and the cell of each entry registered in the entry control table ECT is transferred in time division repetitively in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a network constructed by interconnecting a plurality of computers.
The present invention relates to a packet data transfer control device that is divided into a plurality of small unit cells and relays the transfer of packet data (also referred to as a frame or frame data) that is transferred in a time-division manner using the cell as a transfer unit.

[0002]

2. Description of the Related Art A packet data transfer control device is, as represented by a switching hub, a plurality of computers, a plurality of networks, or a network in which these are mixed and connected to form an integrated network. An apparatus for constructing an environment, having a function of relaying transfer of packet data, which is communication data between computers.

FIG. 7 shows a conceptual diagram of an example of a packet data transfer control device. In the illustrated example, the packet data transfer control device 20 includes n ports P1, P2,.
-1, Pn, and each port P1, P2,
, Pn−1, Pn, corresponding to the packet memories PM1, PM2,.
n-1, PMn and an entry control table or the like for registering a packet data transfer request as an entry,
Port controllers PTC1, PTC2,..., PTC controlling the respective ports P1, P2,.
n-1, PTCn.

[0004] Each port controller PTC1, PT
, PTCn-1, PTCn are switch buses SB for transmitting and receiving packet data, and port controllers PTC1, PTC2,..., PTCn-1,.
Are interconnected via a control bus CB for transmitting and receiving control signals used between the PTCs,
Packet memories PM1, PM2,..., PMn-1, PM
n is the corresponding port controller PTC1,
PTC2,..., PTCn-1, and PTCn are connected one-to-one.

The packet data transfer control device 2
0, a computer PC1 is connected to the port P1, a computer PC2 is connected to the port P2,..., A computer PCn-1 is connected to the port Pn-1, and the computers PCn1 and PCn2 are connected to the port Pn. Is connected. Here, for example, port P1
From computer PC1 connected to port Pn
Assume that packet data is transferred to the computer PCn-1 connected to the PC-1.

[0006] The packet data transferred from the computer PC1 is first transferred to a port controller PTC1 which controls the port P1. The header information of the packet data includes the computer PC that is the transmission source (source).
1 and the network address of the computer PCn-1 serving as the destination (destination). Based on this, the source port P1 and the destination port Pn- corresponding to the respective network addresses are included.
1 is detected.

Here, the port Pn-
1 is not communicating (BUSY), the packet data held in the port controller PTC1 that controls the port P1 is divided into a plurality of small unit cells, and the port Pn
-1 is sequentially transferred directly to the port controller PTCn-1 which controls -1 and is output as continuous packet data from the port Pn-1. And the computer PCn-
1 determines whether or not the packet data is to be received by itself, based on the header information of the packet data output from the port Pn-1, and receives the packet data.

On the other hand, the port Pn-1 serving as a destination port
Is communicating, the packet data held in the port controller PTC1 that controls the port P1 is
The transfer request is temporarily stored in the first packet memory PM1, and this transfer request is sequentially registered in the entry control table as a new entry that has not been transmitted as a standby control state by the port controller PTC1.

However, in such a configuration, it is determined whether or not it is possible to transmit a new entry or a packet data input from another port in the standby state. Must be monitored via the control bus CB, and control of which port should be prioritized must be similarly performed via the control bus CB, and the period for this control is a packetized packet. Switching data to switching bus S
B, and the bus efficiency was extremely poor.

[0010] In particular, in a system for increasing the efficiency of the switching bus SB by dividing packet data into cells for improving bus efficiency and multiplexing data transfer, how to solve this problem is of great concern. Met. Further, in the packet data transfer control device 20, each of the port controllers PTC1, PTC2,.
1, PTCn, the packet memories PM1, PM
2,..., PMn−1, PMn, there is also a problem that the cost becomes very high.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the communication efficiency of packetized packet data and reduce the cost by considering the problems based on the prior art. An object of the present invention is to provide a transfer control device.

[0012]

In order to achieve the above object, the present invention divides packet data into a plurality of small unit cells, and transfers each packet data cell from a source port to a destination port. A packet data transfer control device for transferring in a time-division manner, a packet memory for temporarily storing the packet data when the packet data cannot be directly transferred from the source port to the destination port,
An entry control table for registering a packet data transfer request as an entry, and first and second entry number reference tables for registering the entry numbers of the respective entries registered in the entry control table in accordance with the transfer order; Referring to an entry number registered in one of the first and second entry number reference tables, one cell of packet data corresponding to each entry registered in the entry control table is time-divided by one. Each time the packet data is transferred, the entry number of the entry for which the transfer of the packet data has not been completed is re-registered in the other second or first entry number reference table, and the entries are registered in all the entries registered in the entry control table. Turn one cell of the corresponding packet data into time division Each time the packet data cell corresponding to each entry registered in the entry control table is repeatedly transferred in a time-division manner by alternately referring to the first or second entry number reference table. Is provided.

Here, the packet data transfer control device further comprises a free entry number management table for managing a place where no entry is registered in the entry control table. With reference to the empty entry number registered in, the new entry is registered in the entry control table, with reference to the entry number registered in one of the first or second entry number reference table, Each time one cell of packet data corresponding to each entry registered in the entry control table is transferred in a time-division manner, the entry number of the entry for which the transfer of the packet data has been completed is registered in the empty entry number management table. Is preferred.

[0014]

In the packet data transfer control device according to the present invention, when a request for transferring packet data from a source port to a destination port occurs, this transfer request refers to an empty entry number management table, and An empty entry is registered as a new entry, and the entry number is additionally registered in the first or second entry number reference table. The transfer of the packet data corresponding to each entry registered in the entry control table is basically performed in the registered order with reference to the first or second entry number reference table. Also, the packet data corresponding to each entry is divided into a plurality of small unit cells, and the cells are independently transferred in a time-division manner for each entry.

At this time, if the receiving port is not communicating, the packet data corresponding to this entry is transferred from the source port to the receiving port, and if the receiving port is communicating, the packet data corresponding to this entry is transferred. The packet data to be transferred is once transferred from the source port to the packet memory, and a transfer request from the packet memory to which the packet data is transferred to the destination port of the packet memory is added to the entry control table as a new entry. The packet data registered and transferred to the packet memory is transferred to the destination port when the destination port stops communicating.

Here, when the cells of each entry are transferred one by one in a time-division manner, the entry whose transfer has not been completed is stored in the second or first entry number reference table whose entry number is not being referred to. The entry that has been re-registered and the time series of the transfer has been updated and the transfer has been completed has its entry number additionally registered in the empty entry number management table. In this way, by referring to one of the first or second entry number reference tables, the cells of each entry are transferred one by one, and then the other second or first entry number is transferred. With reference to the lookup table, one cell of each entry is transferred in a time-division manner,
In the same manner, similarly, the cells of the packet data corresponding to each transferable entry are transferred in a time-division manner by alternately referring to the first or second entry number reference table.

As described above, by alternately referencing the first and second entry number reference tables, the time series of all entries registered in the entry control table can be completely retained, and thus transfer is possible. Data can be transferred in a time-division manner, and communication efficiency can be maximized. In addition, by managing the entry entry table where no entry is registered in the empty entry number management table, the entry control table can be used efficiently, and the cost can be reduced by using a common packet memory. can do.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a packet data transfer control device according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a conceptual diagram of one embodiment showing the internal configuration of the packet data transfer control device of the present invention. The illustrated example of the packet data transfer control device 10 includes n ports P
, Pn, a packet transfer information interpreting unit PRP, a packet controller PQC, a packet memory PM, and respective ports P1, P2,.
Port controllers PTC1, PTC2 for controlling
, PTCn and a transfer reference table group TRT.

Here, each port controller PTC
1, PTC2,..., PTCn-1, PTCn are a switch bus SB for transmitting and receiving packet data, and a packet transfer information interpreting unit PR for transmitting header information of the packet data.
, PTC, a header bus HB for outputting to the P, and port controllers PTC1, PTC2,.
n are connected to each other via a control bus CB for transmitting and receiving control signals used between n.

Further, the packet transfer information interpreting section PRP
The packet controller PQC and the packet memory PM are connected to the header bus HB and the control bus CB, and similarly, are connected to the switch bus SB and the control bus CB. Packet transfer information interpreter P
The RP and the packet controller PQC are connected to the transfer reference table group TRT, and the packet transfer information interpreter P
The packet transfer information output from the RP is input to the packet controller PQC.

Further, a computer PC1 is connected to the port P1 of the packet data transfer control device 10 in the illustrated example, and similarly, a computer PC2 is connected to the port P2,..., The computers PCn1 and PCn2 are connected to the port Pn. It is connected.

The illustrated packet data transfer control device 10
, The packet transfer information interpreting unit PRP refers to an address conversion table ATT described later based on the header information of the packet data output from each of the port controllers PTC1, PTC2,. Interpret to which port the packet data is to be transferred, and transmit the packet transfer information as the interpretation result to the packet controller PQC.
Output to

The packet controller PQC refers to a port monitor table PMT, which will be described later, and checks the communication state of each of the ports P1, P2,.
The packet data is controlled from the source port to the destination port or the packet memory PM based on information indicating whether or not communication is in progress (BUSY), packet transfer information input from the packet transfer information interpreter PRP, and the like. hand,
The packet is transferred from the source port to the packet memory PM or from the packet memory PM to the destination port.

Next, the packet memory PM stores the data when the destination port of the packet data is communicating, or when the destination port is not communicating to maintain the time series of the transfer of the packet data. However, when there is packet data to be transferred prior to this packet data, each port controller PTC1, PTC2,
.., For temporarily storing packet data output from the PTCn.

Here, in the packet data transfer control device 10 of the present invention, like the conventional packet data transfer control device 20 shown in FIG. 7, each of the port controllers PTC1, PTC2,. P
Rather than providing the packet memories PM1, PM2, PMn for each TCn, as shown in FIG. 1, by sharing one packet memory PM for all the port controllers PTC1, PTC2,.
There is an advantage that the cost of the entire apparatus can be reduced.

Subsequently, the port controllers PTC1, PTC
, PTCn are computers PC1, PC2,..., PCn1 and PCn2 connected to the corresponding ports P1, P2,.
And outputs it to the switch bus SB, and conversely, receives packet data transferred by the packet controller PQC,
This is output from each of the ports P1, P2,..., Pn.

On the switch bus SB, for example, FIG.
As in the conventional packet data transfer control device 20 shown in FIG. 1, cell data is transferred from each port controller in a time-division manner. Therefore, the packet data from the port P1 is cellized (cell i) and
At the same time as transferring the packet data to n-1, the packet data from the port Pn can be cellized (cell k) and transferred to the port P2. At this time, there is no relationship between the cells, and independent transfer is possible.

This is because each port controller PTC
1, PTC2,..., PTCn have a data communication speed of, for example, 10 Mb (megabit) / sec, whereas a switch bus S for transmitting and receiving packet data is used.
B has a data communication rate of, for example, 1 Gb (gigabit) / second, and each packet data is divided into a plurality of small unit cells, and is transferred in a time-division manner using this cell as a transfer unit. In other words, it becomes possible only after multiplexing.

FIG. 2 shows a conceptual diagram of one embodiment of the transfer reference table group. The transfer reference table group TRT is:
Various data necessary for packet data transfer are registered in advance, or newly registered in response to a transfer request, and have various tables referred to when transferring packet data. Are the address translation table ATT and the port monitor table PMT
, An entry control table ECT, first and second
Entry number reference tables ERT1 and ERT2,
And an empty entry number management table EMT.

The address translation table ATT is mutually connected to the packet transfer information interpreting unit PRP, and the port monitor table PMT and the entry control table ECT are mutually connected to the packet controller PQC. Note that the connection between each table conceptually indicates the direction in which each table acts, and does not necessarily indicate a physical connection between the tables.

In the transfer reference table group TRT, ports P1, P2,..., Pn corresponding to the network addresses of the computers PC1, PC2,.
Information is registered. Packet transfer information interpreter PR
P, each port controller PTC1, PTC
, PTCn, the header information of the packet data is interpreted, and the network addresses of the computers PC1, PC2,..., PCn1 and PCn2 to which the packet data are received correspond to this using the address translation table ATT. Are converted to ports P1, P2,..., Pn.

The port monitor table PMT stores each of the ports P1, P2,.
For managing the current cell data reception state of Pn, as shown in FIG. 3, n entries corresponding to the respective cell data reception ports P1, P2,..., Pn are prepared. Have been. In the entry, the port number of the cell data transmission source is registered corresponding to each entry. Therefore, for example, when the packetized packet data is transferred from the port P1 to the port P2, the port P1 is registered in the entry of the port P2, and the port P2 is already used as the cell data receiving port, and the further transfer request is made. Will be unacceptable if it comes from another port.

Subsequently, the entry control table ECT
Are the packet data temporarily stored in the packet memory PM and the port controllers PTC1, PTC
This is a table for controlling all packet data transfer requests from C2,..., PTCn as transfer entries. For example, the entry control table E shown in FIG.
In the CT, k entries indicated by entry numbers E1, E2,..., Ek are registered. Each entry is a destination port of the packet data, a source port of the packet data, and a packet storing the port. It is composed of a storage address of the memory PM and the like.

The configuration of the entry control table ECT is not limited to this embodiment. For example, as shown in FIG. 5, in order to improve the operation speed, a relatively high-speed and small-capacity entry control cache table ECCT is used.
And a relatively low-speed and large-capacity entry control main table ECMT. At this time,
Some transferable entries are transferred to the entry control cache table ECCT from the entry control main table ECMT.

Here, when the source ports are direct port controllers PTC1, PTC2,..., PTCn,
The storage address described above is the port controller PTC
1, PTC2,..., PTCn itself. Therefore, as shown in FIG. 4, for example, the first bit of the storage address data is set as a storage address valid bit, and when the storage address valid bit is '0', for example, the flag indicating this directly indicates the port controller. Conversely, when it is '1', the data below it may indicate the address of the packet memory PM.

The information on each packet data is obtained from the address translation table ATT. Here, the port monitor table PMT is
Here's how it works. As described above, the port monitor table PMT indicates the current reception status of the cell data of each port as the name implies, and here the header information of the new packet data is transmitted to the packet transfer information interpreter PRP. Is input, and the packet data is transferred from port P3 to port P1.

At this time, as shown in the entry of the entry number E1 in FIG.
2 and the other packet data cannot be received at that time. Therefore, the packet data from the port P3 is temporarily registered in the entry control table ECT so as to be transferred to the packet memory PM. For example, in the case of the present embodiment, as shown in the entry control table ECT of FIG. 4, this entry is registered as the entry of the entry number E2.

That is, in this entry, the destination port is P1 and the source port is P3. For example, the storage address valid bit is set to “1” and the storage destination address of the data is registered. That is, when the storage address valid bit is set to "1", the packet data is not directly transferred from the source port to the destination port, but is transferred from the source port to the packet memory PM. Packet memory PM
The transfer of the packet data is performed in two stages, for example, the packet data is transferred to the destination port.

New entries registered in the entry control table ECT are sequentially registered with reference to an empty entry number management table EMT described later. This empty entry number is generated randomly. The reason is that each packet data is divided into cells, and basically, is transferred in a time-division manner for each cell of each entry in the order registered in the entry control table ECT. This is because, since the length of the data is different, the time until the transfer of each entry is completed varies, and an empty entry number for registering a new entry is randomly generated.

Therefore, a new entry is also registered at random, and transfer is performed sequentially in units of cells. In the packet data transfer control device 10 of the present invention, the transfer of the randomly registered entry is controlled in order. Are provided with first and second entry number reference tables ERT1 and ERT2. The first and second entry number reference tables ERT1, ERT2
Have entry numbers E1 and E corresponding to all entries registered in the entry control table ECT.
2,..., Ek are stored to hold the order of transfer.

The first and second entry number reference tables ERT1 and ERT2 are described below.
At the same time, only one of them is alternately referred to. When a new entry is registered in the entry control table ECT, one of the currently referred first or second entry number reference tables ERT1 and ERT2 contains, for example, all existing entry numbers currently held. Finally, the new entry number is added and registered.

An example of this control will be briefly described below with reference to FIGS. 6 (a) and 6 (b). First, in the entry number reference table ERT1 of FIG.
, Ek are registered. For example, according to the order of this entry number,
By referring to the contents held in each entry of the entry control table ECT, one cell is transferred from the source port to the destination port in a time-division manner independently for all registered entries. Here, each time one cell is transferred, the entry number corresponding to each entry is re-registered in the other entry number reference table ERT2 as a transfer candidate entry for the next cell. At this time, a packet whose transfer of the packet data corresponding to the entry has been completed is not re-registered.

For example, as shown in FIG. 7A, if the transfer of the packet data corresponding to the entry number E2 is completed, the entry number E2 is not re-registered in the entry number reference table ERT2, and When the new packet data is registered in the entry number management table EMT and new packet data comes and the transfer request entry is registered in the entry control table ECT, it is registered as the new entry at the lowest position of the entry number reference table being referred to. . If the transfer of the packet data of the entry number E3 is completed by the transfer of the cell data, as shown in FIG.
Are additionally registered in the empty entry number management table EMT, and E is stored in the entry number reference table ERT1.
Only the entry numbers of 1, E4,..., Ek are re-registered.

As described above, by referring to the entry numbers held in one of the first and second entry number reference tables ERT1 and ERT2, the cell of the packet data corresponding to each entry is sequentially set to 1 Each time one transfer is completed, the number of the entry whose transfer has not been completed is sequentially re-registered in the other second or first entry number reference tables ERT2 and ERT1, and the entry number corresponding to the entry whose transfer has been completed is Are sequentially registered in an empty entry number management table EMT described later.

The first and second entry number reference tables ERT1 and ERT2 are provided, and the transfer order is constantly updated every time one cell of each entry is transferred in a time-division manner. Time series of transfer can be maintained. As shown in FIGS. 7A and 7B, the last entry number registered in the first and second entry number reference tables ERT1 and ERT2 is the last entry number. It includes an end flag END meaning that there is, and recognizes this END flag,
The cell is exchanged with the other entry number reference table, and the cell transfer of the entry registered therein is controlled.

Each entry registered in the first and second entry number reference tables ERT1 and ERT2 is used to delete packet data that cannot be transferred even after a certain period of time has passed as a timeout. For example, to provide a timer field,
It goes without saying that various attributes may be provided. At this time, the value of the timer field is decremented when the first or second entry number reference table ERT1 or ERT2 is referred to, for example, decremented by one, the value becomes 0, and the entry becomes If the transfer has not been started yet, it is also possible to control such that the entry corresponding to this is deleted.

The packet data transfer control device 10 of the present invention
Has basically the above configuration.
Next, the operation of the packet data transfer control device 10 of the present invention will be described with reference to the computer P connected to the port P1.
Computer P connected to port P2 from C1
The case where packet data is transferred to C2 will be described as an example.

The header information of the packet data output from the computer PC1 is input to the packet transfer information interpreter PRP via the header bus HB. In the packet transfer information interpreting unit PRP, the ports P1 and P2 to which the computers PC1 and PC2 are connected are detected with reference to the address conversion table ATT. This detection result is output as packet transfer information and input to the packet controller PQC.

In each entry of the port monitor table PMT, the source port of the packet data to be transferred to the corresponding port P1, P2,..., Pn is registered based on the packet transfer information. The packet controller PQC uses the port monitor table PMT
To confirm whether or not the receiving port P2 is communicating, and if not, the port monitor table PMT
The port P1 is registered in the port P2 of the port No. 2, and it is specified that the transfer of the packet data is performed during this time.

Further, the packet controller PQC refers to the empty entry number management table EMT, and places the empty entry in the entry control table ECT at the position of the empty entry.
This transfer request is registered as a new entry, and the entry number corresponding to this entry is stored in one of the first or second entry number reference tables ERT1 and ERT2 currently being referenced. Register at the end of all entry numbers.

The transfer of the packet data corresponding to each entry registered in the entry control table ECT is performed by the first or second entry number reference table ER.
With reference to T1 and ERT2, the registration is basically performed in the registered order.

Here, when the port P2 is not communicating,
That is, if the storage address valid bit held in the entry corresponding to this transfer in the entry control table ECT is “0”, the packet controller P
QC is, as already mentioned, the port controller PTC
The packet data output from 1 is divided into a plurality of small unit cells and transferred directly to the port controller PTC2 via the switch bus SB. Port controller PT
The packet data transferred to C2 is output from the port P2, and the computer PC2 determines whether or not the packet data is to be received by itself based on the header information of the packet data output from the port P2 and receives the packet data. I do.

On the other hand, when the port P2 is communicating,
That is, if the storage address valid bit is “1”, the packet controller PQC sends the switch bus SB
, The packet data output from the port controller PTC1 is temporarily transferred to the packet memory PM, and the transfer request from the packet memory PM to which the packet data has been transferred to the port P2 is set as a new entry. Register in the control table ECT. This entry is processed when the port P2 stops communicating.

As described above, each packet data is divided into a plurality of small unit cells, and each packet data cell is sequentially transferred in a time-division manner. That is, the transfer of the packet data is multiplexed. Have been. Therefore, in the transfer of the packet data corresponding to each entry, first, the first cell of the packet data corresponding to each transferable entry is transferred, and so on.
, A third cell,..., In that order. These cells are sequentially transmitted to the switch bus SB in a time division manner and transferred independently for each packet data.

Here, each time one cell of packet data corresponding to each transferable entry is transferred in a time-division manner, for example, by referring to the entry number registered in one of the first entry number reference tables ERT1. The entry whose transfer has not been completed has its entry number set to the other second entry number reference table ERT2.
, And the entry whose transfer has been completed has its entry number additionally registered in the empty entry number management table EMT.

As described above, the entry numbers registered in the first or second entry number reference tables ERT1 and ERT2 are alternately referred to, and the cell of the packet data corresponding to each transferable entry is transferred in a time-division manner. Is done. As described above, the time series of transfer is constantly updated by alternately referring to the first or second entry number reference tables ERT1 and ERT2, so that the time series of each entry of the entry control table ECT that is randomly entered is changed. Can be maintained, thereby maximizing the efficiency of multiplexed communication.

Although the present invention has been described with reference to one embodiment, the packet data transfer control device of the present invention is not limited to this embodiment, and various types of packet data transfer control devices may be used without departing from the spirit of the present invention. Needless to say, it is possible to make changes.

[0059]

As described in detail above, the packet data transfer control device according to the present invention divides packet data into a plurality of small unit cells and transmits each packet data cell in a time-division manner. Applied to a multiplexed network, it has a common packet memory, first and second entry number reference tables, and an empty entry number management table in addition to an entry control table. According to the packet data transfer control device of the present invention, by alternately referring to the first and second entry number reference tables, various lengths that are randomly input from each port and registered in the entry control table can be obtained. The time series of each entry possessed can be completely retained, and thereby, transferable packet data can be transferred in a time-division manner. Therefore, for example, there is no need to wait for transferable packet data due to untransferable packet data, and the communication efficiency can be improved to the maximum. Also,
According to the packet data transfer control device of the present invention, by providing the empty entry number management table, the entry control table can be used effectively, and the cost is reduced because the packet memory is shared. There is also an effect that can be done.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of one embodiment showing an internal configuration of a packet data transfer control device of the present invention.

FIG. 2 is a conceptual diagram of one embodiment of a transfer reference table group.

FIG. 3 is a conceptual diagram of one embodiment of a port monitor table.

FIG. 4 is a conceptual diagram of one embodiment of an entry control table.

FIG. 5 is a conceptual diagram of another embodiment of the entry control table.

FIGS. 6A and 6B are conceptual diagrams of an embodiment of an entry number reference table and an empty entry number management table.

FIG. 7 is a conceptual diagram of an example of a packet data transfer control device.

[Explanation of symbols]

10, 20, 30 Packet data transfer control device PRP packet transfer information interpreter PQC packet controller PM packet memory PTC1, PTC2,..., PTCn port controller SB switch bus HB header bus CB control bus P1, P2,. PC2,..., PCn1 and PCn2 Computer TRT transfer reference table group ATT address conversion table PMT port monitor table ECT entry control table ERT1, ERT2 entry number reference table EMT free entry number management table MCCT memory control cache table MCMT memory control main table E1, E2, ..., Ek Entry number END End flag

Claims (2)

[Claims] 1. A packet data transfer control device for dividing packet data into a plurality of small unit cells and transferring each packet data cell from a source port to a destination port in a time-division manner. When packet data cannot be directly transferred from the source port to the destination port, a packet memory for temporarily storing the packet data, an entry control table for registering packet data transfer requests as entries, and an entry control table for First and second entry number reference tables for registering the entry numbers of each registered entry in accordance with the transfer order, and the entries registered in one of the first and second entry number reference tables Referring to the numbers, each registered in the entry control table Every time one cell of the packet data corresponding to the entry is transferred in a time-division manner, the entry number of the entry whose transfer of the packet data has not been completed is re-registered in the other second or first entry number reference table. Each time one cell of the packet data corresponding to all entries registered in the entry control table is transferred in a time-division manner, the first or second entry number reference table is alternately referred to, and A packet data transfer control device for repeatedly transferring cells of packet data corresponding to each entry registered in an entry control table in a time division manner. 2. The packet data transfer control device according to claim 1, further comprising: an empty entry number management table for managing a place where no entry is registered in said entry control table. A new entry is registered in the entry control table with reference to an empty entry number registered in the entry number management table, and an entry number registered in one of the first or second entry number reference table is entered. Each time one cell of the packet data corresponding to each entry registered in the entry control table is transferred in a time-division manner, the entry number of the entry for which the transfer of the packet data has been completed is replaced with the empty entry number. Packet data transfer characterized by registration in a management table Control device.