Packet switch

• US 5,177,736 A
• Filed: 02/04/1991
• Issued: 01/05/1993
• Est. Priority Date: 02/07/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd., Hitachi Software Engineering Co., Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd., Hitachi Software Engineering Co., Ltd. (Hitachi, Ltd.)
• Inventors: Tanabe, Shiro, Kihara, Yoshiaki, Kubo, Akinori
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Blum, Russell
• Application Number:
  US07/649,966
• Time in Patent Office: 701 Days
• Field of Search: 370/15, 370/60, 370/94.1
• US Class Current: 370/419
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 2012/561 Star, e.g. cross-connect, concentrator, subscriber group equipment, remote electronics
• CPC Class Codes: H04L 49/106 using space switching, e.g. crossbar or matrix
• CPC Class Codes: H04L 49/1576 Crossbar or matrix
• CPC Class Codes: H04L 49/255 Control mechanisms for ATM switching fabrics
• CPC Class Codes: H04L 49/309 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/455 Provisions for supporting expansion in ATM switches

Abstract

A packet switch comprises a switch having a plurality of input lines and a plurality of output lines for sending a packet supplied from each of the input lines to one of the output lines selected in accordance with routing information attached to each packet, a plurality of pairs of input/output lines connected to terminals or other switches, a plurality of line interface provided one for each of the input/output lines and each connected to one of the input lines and one of the output lines of the switch, and a controller connected to one of the input lines and one of the output lines of the switch. Control information is communicated between the controller and the line interfaces or the switch via a control packet through the switch. The switch may be a plurality of multi-stage connected unit switches and input lines and output lines thereof are divided into a plurality of groups. The controller is connected to an input line of one of first stage unit switches and an output line of one of final stage unit switches of one of the switch groups.

Claims

1. A packet switching system comprising:

switch means having a plurality of input lines and a plurality of output lines for switching a packet supplied from any one of the input lines to one of the output lines selected in accordance with routing information put to the packet;

a plurality of line interface means each connected to one of the input lines and one of the output lines of said switch means;

a plurality of pairs of lines each including an outer input line and an outer output line, each pair of lines being connected to one of said line interface means, for communicating user packets between said switch means and a terminal device or other switching system connected to said pair of lines; and

central processing means connected to one of the input lines and one of the output lines of said switch means;

said central processing means having means for generating internal control packets to be delivered to said line interface means or said switch means to control the switching of user packets and means for outputting said internal control packets to said one input line of the switch means, each of said internal control packet including routing information for specifying a route toward destination of the internal control packet and internal control information to be informed to said line interface means or said switch means, each of said internal control packets being delivered to its said line interface means or said switch means through said switch means.

2. A packet switching system according to claim 1:

said switch means includes a plurality of unit switches each having a plurality of input lines, a plurality of output lines, and means for transferring a packet received from one of said input lines thereof to one of said output lines thereof selected on the basis of routing information of the received packet, and a plurality of switch control means provided for each unit switch, said unit switches being arranged in rows and columns, the input lines of unit switches in the first column forming the input lines of said switch means, the output lines of unit switches in the final column forming the output lines of said unit switch means, said unit switches being connected so as to transfer internal control packets and user packets received by any one of the unit switches in the first column to any one of the unit switches in the final column; and

each of said switch control means transmits and receives internal control packets to and from said central processing means through the unit switch connected to said switch control means.

3. A packet switching system according to claim 2 wherein

said line interface means includes means for routing-back an internal control packet supplied from the output line of said switch means to the input lines of said switch means;

whereby an internal control packet addressed to a particular switch control means supplied from said central processing means or an internal control packet transmitted from a particular control means switch to said central processing means is delivered to its destination through said line interface means.

4. A packet switching system according to claim 3 wherein

each of said line interface means includes means for updating the routing information of the internal control packet transmitted from one of said switch control means and addressed to the central processing unit or one of the other switch control means, the updated internal control packet being routed back to said switch means by said routing-back means and delivered to its destination by receiving switching operation based on the updated routing information.

5. A packet switching system according to claim 4 wherein

said central processing unit, each of said line interface means and each of said switch control means includes means for generating internal control packets with the routing information defined in the sequence of passage of the internal control packet through the unit switch;

each of said unit switches selects the output line to which the received packet is to be sent in accordance with the routing information of a particular order corresponding to the unit switch.

6. A packet switch comprising:

switch means having a plurality of input lines and a plurality of output lines for sending a packet supplied from each of the input lines to one of the output lines selected in accordance with identification information put to each packet;

a plurality of pairs of lines, each pair of lines having an input line and an output line connected to terminals or other switch means;

a plurality of line interface means one for each pair of lines, each interface means being connected to one of the input lines and one of the output lines of said switch means; and

central processing means connected to one of the input lines and one of the output lines of said switch means;

whereby control information is communicated between said central processing means and the line interface means or the switch means via a control packet through the input lines or the output lines of said switch means;

said unit switch means includes a plurality of multi-stage connected switches, each having a plurality of input lines and a plurality of output lines, and unit switch control means provided for each unit switch;

said input lines of succeeding unit switches being connected to output lines of preceding unit switches and input lines of a first unit switch being said input lines of said switch means and output lines of a final unit switch being said output lines of said switch means;

each of said switch control means transmits and receives the control packet to and from said central processing means through the unit switch connected to said switch control means;

said line interface means includes means for routing back the control packet supplied from the output line of said switch means to the input lines of said switch means;

the control packet addressed to a particular switch control means supplied from said central processing means or the control packet sent from a particular switch control means to said central processing means is delivered to a destination means through said line interface means;

wherein each source of the control packet includes means for adding to the control packet to be sent a logical channel number predetermined by the type of the destination equipment means of the control packet and routing information for the control packet;

each of said unit switches selects an output line to which the received packet is sent in accordance with the route information put on the received packet; and

each of said line interface means includes means for updating the routing information of the control packet received from one of said switch control means and addressed to the central processing unit or another switch control means.

7. A packet switch comprising:

switch means having a plurality of input lines and a plurality of output lines for sending a packet supplied from each of the input lines to one of the output lines selected in accordance with identification information put to each packet;

a plurality of pairs of lines, each pair of lines having an input line and an output line connected to terminals or other switch means;

a plurality of line interface means one for each pair of lines, each interface means being connected to one of the input lines and one of the output lines of said switch means; and

central processing means connected to one of the input lines and one of the output lines of said switch means;

whereby control information is communicated between said central processing means and the line interface means or the switch means via a control packet through the input lines or the output lines of said switch means;

said switch means includes a plurality of multi-stage connected unit switches, each having a plurality of input lines and a plurality of output lines, and switch control means provided for each unit switch;

said input lines of succeeding unit switches being connected to output lines of preceding unit switches and input lines of a first unit switch being said input lines of said switch means and output lines of a final unit switch being said output lines of said switch means;

each of said switch control means transmits and receives the control packet to and from said central processing means through the unit switch connected to said switch control means;

said line interface means includes means for routing back the control packet supplied from the output line of said switch means to the input line of said switch means;

the control packet addressed to a particular switch control means supplied from said central processing means or the control packet sent from a particular switch control means to said central processing means is delivered to a destination means through said line interface means;

said central processing unit, each of said line interface means and said switch control means include means for sending the control packet with the routing information defined as the sequence of passage of the control packet through the unit switches, added thereto;

each of said unit switches selects the output line to which the received packet is to be sent in accordance with the routing information of a particular order corresponding to the unit switch; and

each of said line interface means includes means for routing back the control packet to said switch means after having updated the order of the routing information includes in the control packet received from said switch means and addressed to said central processing means or one of said switch control means.

8. A packet switch comprising:

switch means having a plurality of input lines and a plurality of output lines for sending a packet supplied from each of the input lines to one of the output lines selected in accordance with identification information put to each packet;

a plurality of pairs of lines, each pair of lines having an input line and an output line connected to terminals or other switch means;

a plurality of line interface means one for each pair of lines, each interface means being connected to one of the input lines and one of the output lines of said switch means; and

central processing means connected to one of the input lines and one of the output lines of said switch means;

whereby control information is communicated between said central processing means and the line interface means or the switch means via a control packet through the input lines or the output lines of said switch means;

said switch means includes a plurality of multi-stage connected unit switches, each having a plurality of input lines and a plurality of output liens, and switch control means provided for each unit switch;

said input lines of succeeding unit switches being connected to output lines of preceding unit switches and input lines of a first unit switch being said input lines of said switch means and output lines of a final unit switch being said output lines of said switch means input;

each of said switch control means transmits and receives the control packet to and from said central processing means through the unit switch connected to said switch control means;

said unit switches of said switch means are divided into a plurality of switch groups;

each of said switch groups includes packet routing-back means connected to an input line of one of first stage unit switches and an output line of one of final stage switches;

said central processing means is connected to an input line of the first stage switches of a particular one switch group and output line of one of the final stage unit switches of the particular switch group; and

particular one of the control packets sent from said central processing means or said switch control means is delivered to the destination means through one of the packet routing-back means.

9. A packet switch comprising:

switch means having a plurality of input lines and a plurality of output lines for sending a packet supplied from each of the input lines to one of the output lines selected in accordance with identification information put to each packet;

a plurality of pairs of lines, each pair of lines having a input line and an output line connected to terminals or other switch means;

a plurality of line interface means one for each pair of lines, each interface means being connected to one of the input lines and one of the output lines of said switch means;

central processing means connected to one of the input lines and one of the output lines of said switch means;

whereby control information is communicated between said central processing means and the line interface means or the switch means via a control packet through the input lines or the output lines of said switch means;

said switch means includes a plurality of multi-stage connected unit switches, each having a plurality of input lines and a plurality of output lines, switch control means provided for each unit switch;

said input lines of succeeding unit switches being connected to output lines of preceding unit switches and input lines of a first unit switch being said input lines of said switch means and output lines of a final unit switch being said output lines of said switch means;

each of said switch control means transmits and receives the control packet to and from said central processing means through the unit switch connected to said switch control means;

said unit switches of said switch means are divided into a plurality of switch groups;

each of said switch groups includes packet routing-back means connected to an input line of one of first stage unit switches and an output line of one of final stage unit switches;

said central processing means is connected to an input line of the first stage unit switches of a particular one switch group and an output line of one of the final stage unit switches of the particular switch group;

a particular one of the control packets sent from said central processing means or said switch control means is delivered to the destination means through one of the packet routing-back means;

said central processing means, said line interface means and said switch control means include means for sending the control packet in the format having the logical channel number predetermined by the type of destination equipment means of the control packet and the routing information for the control packet;

each of said unit switches selects the output line to which the received packet is to be sent in accordance with the routing information included in the received packet; and

said packet routing-back means updates the routing information of a received packet and routes back the received packet having the updated routing information to the switch means when the received packet is addressed to the central processing means or one of the switch control means.

10. A packet switch comprising:

switch means having a plurality of input lines and a plurality of output lines for sending a packet supplied from each of the input lines to one of the output lines selected in accordance with identification information put to each packet;

a plurality of pairs of lines, each pair of lines having an input line and an output line connected to terminals or other switch means;

a plurality of line interface means one for each pair of lines, each interface means being connected to one of the input lines and one of the output lines of switch means;

central processing means connected to one of the input lines and one of the output lines of said switch means;

whereby control information is communicated between said central processing means and the line interface means or the switch means via a control packet through the input lines or the output lines of said switch means;

said switch means includes a plurality of multi-stage connected unit switches, each having a plurality of input lines and a plurality of output lines, and switch control means provided for each unit switch;

said input lines of succeeding unit switches being connected to output lines of preceding unit switches and input lines of a first unit switch being said input lines of said switch means and output lines of a final unit switch being said output lines of said switch means;

each of said switch control means transmits and receives the control packet to and from said central processing means through the unit switch connected to said switch control means;

said central processing means, said line interface means and said switch control means includes means for adding the routing information in the order of passage of the control packet through the unit switches to the control packet to be sent;

each of said unit switches selects the output line to which the received packet is to be sent in accordance with the routing information of a particular order corresponding to its own unit switch, includes in the received packet; and

each of said packet routing-back means updates the order of the routing information of a received control packet and routes back the received control packet to said switch means when said received control packet is addressed to said central processing means or one of said switch control means.

11. A packet switching system comprising:

switch means having a plurality of input lines and a plurality of output lines for sending a packet supplied from any one of the input lines to one of the output lines selected in accordance with routing information put to each packet;

a plurality of line interface means each connected to one of the input lines an done of the output lines of said switch means;

a plurality of pairs of lines, each pair of lines having an outer input line and outer output line, each pair of lines being connected to one of said line interface means, for communicating user packet between said switch means and a terminal device or other switching system connected to the pair of lines;

central processing means, connected to one of the input lines and one of the output lines of said switch means, including means for generating internal control packets to be delivered to said line interface means or said switch means; and

a plurality of packet routing-back means each connected with one of input lines of said switch means and one of output lines of said switch means;

said switch means comprising a plurality of unit switches divided into a plurality of switch groups and a plurality of switch control means provided for each switch;

each of said unit switches having a plurality of input lines, a plurality of output lines, and means of transferring a packet received from one of said input lines thereof to one of output line thereof selected on the basis of routing information of the received packet;

each of said switch groups including at least two unit switches arranged in multi-stage, the input lines of a first stage unit switches forming the input lines of said switch means, the output lines of a final stage unit switches forming the output lines of said switch means, said unit switches being connected so as to transfer internal control packets and user packets received by any one of the first stage unit switches to any one of the final stage unit switches;

each of said packet routing-back means being provided for each switch group and connected to one of input lines of the first stage unit switch and one of output lines of the final stage unit switch in each switch group; and

wherein a particular one of the internal control packets sent out from said central processing means or said switch control means is delivered to its destination through one of the packet routing back means.

12. A packet switch according to claim 11 wherein

said central processing means, said line interface means and said switch control means includes means for sending internal control packets in the format having the logical channel number predetermined by the type of destination of the internal control packet and routing information for specifying a route toward the destination of the internal control packet;

each of said unit switches selects the output line to which the received packet is to be sent in accordance with the routing information includes in the received packet; and

said packet routing-back means includes means for updating the routing information of a received packet and routes back the received packet having updated routing information to the switch means when the received packet is addressed to the central processing means or one of the switch control means.

13. A packet switch according to claim 11 wherein

said central processing means, said line interface means and said switch control means includes means of reading the routing information in the order of passage of the internal control packet through the unit switches to the internal control packet to be sent;

each of said unit switches selects the output line to which the received packet is to be sent out in accordance with the routing information of a particular order corresponding to its own unit switch, includes in the received packet; and

each of said packet routing-back means includes means for updating the order of the routing information of the received internal control packet and routes back the packet to said switch means when said received packet is addressed to said central processing means or one of said switch control means.