Connectionless communications system, its test method, and intra-station control system

• US 6,333,932 B1
• Filed: 08/21/1995
• Issued: 12/25/2001
• Est. Priority Date: 08/22/1994
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Okabe, Kenichi, Nishida, Hiroshi, Murayama, Masami, Itoh, Jun, Watanabe, Yoshihiro, Uchida, Yoshihiro, Abe, Jin, Kagawa, Atsushi, Kato, Yoshiharu, Esaka, Satoshi, Hatano, Takashi, Nishikawa, Yasuhiro, Ishioka, Eiji, Uriu, Shiro, Karakawa, Yoshiyuki, Yamanaka, Hiromi, Tsuruta, Yoshihisa, Hirase, Fumio, Aso, Yasuhiro, Tsutsui, Nobuyuki, Sekine, Shigeru, Kohira, Shouji, Izawa, Naoyuki, Araya, Shinichi, Nakayama, Mikio, Kakuma, Satoshi, Kawataka, Miyuki, Suzuki, Atsuko, Samejima, Noriko, Kobayasi, Yasusi
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): HOM, SHICK C
• Application Number:
  US08/518,110
• Time in Patent Office: 2,318 Days
• Field of Search: 370/228, 370/242, 370/248, 370/249, 370/260, 370/360, 370/383, 370/389, 370/390, 370/395, 370/422, 370/432, 370/467, 370/498, 370/503, 370/471, 370/253, 370/392, 370/230, 370/417, 370/468, 370/377, 370/396, 370/229, 370/252, 379/114
• US Class Current: 370/389
• CPC Class Codes: H04L 2012/5628 Testing
• CPC Class Codes: H04L 2012/5645 Connectionless
• CPC Class Codes: H04L 2012/5652 Cell construction, e.g. including header, packetisation, depacketisation, assembly, reassembly
• CPC Class Codes: H04L 5/16 Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

The quality and performance of the connectionless communications system are improved. When a BOM is received, the destination address DA of the L3-PDU stored in the payload of the BOM is retrieved, and the tag information is obtained from the DA (S11). The output message identifier MID is reserved (S12), and the tag information and output MID are assigned to the BOM (S13). Then, the tag information and output MID are written to the table. When a COM is received, the tag information and output MID are retrieved using the MID of the COM as a key, and the information is provided for the COM (S31 and S32). When an EOM is received, the tag information and output MID are retrieved using the MID of the EOM as a key, and the information is provided for the EOM (S41 and S42). Then, the output MID is released (S43).

Claims

1. A switching system provided in a connectionless communications system for converting a message assigned a destination address into one or more packets, storing the destination in a beginning-of-message (BOM) packet of the packets, and transferring the packets assigned a common message identifier, said system comprising:

determining means for referring to the destination address stored in the BOM packet upon receipt of the BOM packet and determining whether or not the destination of the message refers to a terminal unit accommodated in the switching system which has received the BOM packet;

a first table for retrieving routing information stored in the BOM packet when the destination of the message refers to the terminal unit accommodated in the switching system which has received the BOM packet, and for storing the message identifier set in the BOM packet in association with the routing information;

routing information retrieving means for retrieving the routing information from said first table according to a message identifier set in a continuation-of-message (COM) packet or an end-of-message (EOM) packet in said one or more packets when the COM packet or EOM packet is received;

switching means for switching the COM packet or EOM packet according to the routing information retrieved by said routing information retrieving means;

a second table for storing information designating an output line group having one or more output lines for each switching system provided in said connectionless communications system;

output line determining means for determining an output line group by searching said second table according to the destination address stored in the BOM packet as a key when the destination of the message does not refer to the terminal unit accommodated in the switching system which has received the BOM packet;

a third table for storing the output line group determined by said output line determining means in association with the message identifier of the BOM packet; and

output means for retrieving output line group information from said third table according to a message identifier set in the COM packet or EOM packet in said one or more packets when the COM packet or EOM packet is received, and then outputting the COM packet or EOM packet to a predetermined output line which belongs to the output line group.

2. The switching system according to claim 1, further comprising:

a fourth table storing information for use in developing a group address;

a fifth table storing, in association with the message identifier of the BOM packet, group address development information retrieved from said fourth table according to a group address stored in the BOM packet when the destination address of a received BOM packet refers to the group address stored in said fourth table; and

means for retrieving the group address development information from the fifth table according to the message identifier set in the COM cell or EOM cell when the COM cell or EOM cell is received, and copying the COM packet or EOM packet according to the group address development information.

3. The switching system according to claim 1, further comprising:

buffer means for storing an output packet; and

read control means for controlling a read from said buffer means according to traffic amount for each output line in the output line group.

4. The switching system according to claim 1, further comprising:

discarding means for making a protocol check for each input packet, discarding a protocol-abnormal packet and storing the message identifier set in the protocol-abnormal packet when the input packet is detected as a protocol-abnormal packet, and discarding a packet assigned a stored message identifier.

5. The switching system according to claim 1, further comprising:

pseudo packet generating means for generating and outputting a pseudo EOM packet having the message identifier of a BOM packet when the BOM packet is received but an EOM packet having the message identifier set in the BOM packet is not received within a predetermined time.

6. The switching system according to claim 1, further comprising:

output line assigning means for performing a CRC operation on the destination address and a source address stored in the BOM packet of the message, and for assigning a predetermined output line in the output line group retrieved from said third table according to a value obtained from an operation result.

7. The switching system according to claim 1, further comprising:

band altering means for measuring traffic of each output line and altering a band of each output line according to the traffic.

8. A connectionless communications system having first and second connectionless communications servers respectively for first and second switches for switching fixed-length packets to transmit data between subscribers accommodated in the first and second switches over connectionless communications, and to establish communications by transferring data through permanent virtual circuits (PVC) connecting between each subscriber and the first and second connectionless communications servers, whereby

said first and second connectionless communications servers are connected via a private line;

said first connectionless communications server comprises;

destination determining means for determining whether or not a destination of connectionless communications data from a subscriber accommodated in the first switch is a subscriber accommodated in the second switch; and

transfer means for transferring connectionless communications data to the second connectionless communications server via the private line when the destination of the data refers to a subscriber accommodated by the second switch.

9. An intra-station control device in a switching device for switching cells, comprising:

a counter repeatedly counting a number of cells passing through a switch of the switching device in each first time period;

a calculator calculating a total number of cells counted by said counter in a second time period, the second time period being longer than the first time period, said calculator summing the number of cells counted by said counter in each of the first time periods within the second time period to produce said total number; and

a memory storing the total number of cells calculated by said calculator, wherein the total number of cells stored in said memory is used for calculating a communication bill.

10. The intra-station control device according to claim 9, wherein

said cell count means counts a number of cells passing through the switch for each priority level specified for a cell passing through the switch.

11. The intra-station control device according to claim 9, wherein

said switch for which said cell count means counts the cells is a demultiplexer.

12. The control device according to claim 9, further comprising

discard cell counting means for counting a total number of discarded cells in the predetermined time period, and wherein

the total number of discarded cells counted is stored in said memory.

13. An intra-station control in a switching device for switching cells, comprising:

cell counting means for counting a total number of cells passing through a switch of the switching device in a predetermined time period; and

a memory for storing the total number of cells counted, wherein the total number of cells stored in said memory is used for calculating a communication bill,

wherein said memory comprises first and second storing means, and the total numbers sequentially obtained by said counting means are alternately written in the first and second storing areas.