Network packet switch using shared memory for repeating and bridging packets at media rate

• US 5,720,032 A
• Filed: 01/28/1997
• Issued: 02/17/1998
• Est. Priority Date: 05/12/1992
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Compaq Computer Corporation (HP Inc.)
• Inventors: Zager, Robert P., Picazo, Jose J. Jr., Lee, Paul Kakul
• Primary Examiner(s): Shin, Christopher B.
• Application Number:
  US08/790,163
• Time in Patent Office: 385 Days
• Field of Search: 395/200.02, 395/200.2, 395/200.15, 370/401-408, 370/351
• US Class Current: 709/250
• CPC Class Codes: H04L 12/44 Star or tree networks
• CPC Class Codes: H04L 12/4616 LAN interconnection over a LAN backbone
• CPC Class Codes: H04L 12/462 LAN interconnection over a bridge based backbone
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 41/0213 Standardised network management protocols, e.g. simple network management protocol [SNMP]
• CPC Class Codes: H04L 41/046 comprising network management agents or mobile agents therefor
• CPC Class Codes: H04L 41/26 using dedicated tools for LAN [Local Area Network] management
• CPC Class Codes: H04L 49/201 Multicast operation; Broadcast operation
• CPC Class Codes: H04L 49/25 Routing or path finding in a switch fabric
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/3018 Input queuing
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/357 Fibre channel switches
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers
• CPC Class Codes: H04L 63/0209 Architectural arrangements, e.g. perimeter networks or demilitarized zones
• CPC Class Codes: H04L 63/083 using passwords cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A hub circuit with an integrated bridge circuit carried out in software including a switch for bypassing the bridge process such that the two bridged networks effectively become one network. An in-band management process in software is disclosed which receives and executes network management commands received as data packets from the LANs coupled to the integrated hub/bridge. Also, hardware and software to implement an isolate mode where data packets which would ordinarily be transferred by the bridge process are not transferred except in-band management packets are transferred to the in-band management process regardless of which network from which they arrived. Also disclosed, a packet switching machine having shared high-speed memory with multiple ports, one port coupled to a plurality of LAN controller chips coupled to individual LAN segments and an Ethernet microprocessor that sets up and manages a receive buffer for storing received packets and transferring pointers thereto to a main processor. The main processor is coupled to another port of the memory and analyzes received packets for bridging to other LAN segments or forwarding to an SNMP agent. The main microprocessor and the Ethernet processor coordinate to manage the utilization of storage locations in the shared memory. Another port is coupled to an uplink interface to higher speed backbone media such as FDDI, ATM etc. Speeds up to media rate are achieved by only moving pointers to packets around in memory as opposed to the data of the packets itself. A double password security feature is also implemented in some embodiments to prevent accidental or intentional tampering with system configuration settings.

Claims

1. An apparatus for coupling to first and second networks upon which data packets are being transmitted on one or more data transmission media, comprising:

a physical support for supporting electronic circuitry;

a memory mounted on said physical support for storing data packets to be transmitted on either said first or second network and for storing data packets received from either said first or second network;

a bridge circuit mounted on said physical support and comprising at least first and second network interface circuits coupled to said first and second networks, respectively, each said network having data transmission media, said first and second network interfaces for converting data packets to be transmitted on said first and/or second networks which have been retrieved from said memory into signals capable of propagating on said data transmission media of said first and/or second networks, said first and second networks each coupling a one or more computing machines together for data exchange, each said computing machine having a network address, said first and second network interfaces also for receiving signals transmitted by one or more of said computing machines via said data transmission media of said first or second networks and converting said signals into data packets for storage in said memory, each said data packet having a source network address which is the network address of the computing machine which transmitted said data packet and a destination network address which is the network address of the computing machine for which said data packet is bound, said bridge circuit for selectively forwarding a data packet received from a computing machine coupled to said first network to a computing machine coupled to said second network via said second network interface if the destination address of said data packet received from said computing machine coupled to said first network is the network address of a computing machine coupled to said second network or if said destination address of the received data packet is not known to be the network address of a computing machine coupled to either of said first or second networks, and for selectively forwarding a data packet received from a computing machine coupled to said second network to a computing machine coupled to said first network via said first network interface if the destination address of said data packet received from said computing machine coupled to said second network is the network address of a computing machine coupled to said first network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks;

and wherein at least one of said network interface circuits includes a repeater mounted on said physical support and which has one or more ports each of which is coupled to one of said data transmission media forming part of the network coupled to said network interface circuit which includes said repeater, said repeater for receiving data packets at one or more of said ports and automatically retransmitting said data packets out from the remaining ones of said one or more ports of said repeater thereby causing propagation of said data packets on all other data transmission media coupled to said repeater regardless of the destination network address of any particular data packet being retransmitted;

and further comprising management means including a microprocessor, said management means mounted on said support structure and coupled to said bridge circuit and to said first and second network interface means, for receiving Simple Network Management Protocol commands and carrying out said commands, said microprocessor in said management means, said management means and said memory being shared by and supporting operations of said bridge circuit, and said first and second network interface circuits.

2. An apparatus for coupling to first and second networks upon which data packets are being transmitted on one or more media segments, comprising:

a physical support for supporting electronic circuitry;

a memory for storing data packets to be transmitted on either said first or second network and for storing data packets received from either said first or second network;

a bridge circuit mounted on said physical support and comprising at least first and second network interface circuits coupled to said first and second networks, respectively, each said network having data transmission media, said first and second network interfaces for converting data packets to be transmitted on said first and/or second networks and retrieved from said memory into signals to propagate on said data transmission media of said first and/or second networks, said first and second networks each coupling one or more computing machines together for data exchange, each said computing machine having a network address which is a source network address if said computing machine is transmitting data as signals on either said first or second network and is a destination network address if said computing machine is receiving data as signals from either first or second network, said first and second network interfaces also for receiving signals transmitted by one or more of said computing machines via said data transmission media of said first or second networks and converting said signals into data packets for storage in said memory, each said data packet having a source network address indicating the computing machine which transmitted said data and a destination network address indicating the computing machine for which said data packet is bound, said bridge circuit for selectively forwarding a data packet received from a computing machine coupled to said first network to a computing machine coupled to said second network via said second network interface if the destination address of said data packet received from said computing machine coupled to said first network is the network address of a computing machine coupled to said second network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks, and for selectively forwarding a data packet received from a computing machine coupled to said second network to a computing machine coupled to said first network via said first network interface if the destination address of said data packet received from said computing machine coupled to said second network is the network address of a computing machine coupled to said first network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks;

and wherein at least one of said network interface circuits includes a repeater mounted on said physical support and which has one or more ports each of which is coupled to a media segment forming part of the network coupled to said network interface circuit which includes said repeater, said repeater for receiving data packets at one or more of said ports and automatically retransmitting said data packets out on at least one other of said one or more ports of said repeater regardless of the destination network address of any particular data packet being retransmitted; and

a management circuit coupled to said bridge circuit, said repeater(s) and said network interface circuits, for receiving and carrying out management commands, said management circuit including a microprocessor which is part of said bridge circuit and which is also part of said first and second network interface circuits, said microprocessor being coupled to said bridge circuit and said first and second network interface circuits by a data bus and not a local area network segment, and wherein said memory is also part of said bridge circuit and said first and second network interface circuits, said memory being coupled to said bridge circuit and said first and second network interface circuits by a data bus and not a local area network segment.

3. The apparatus of claim 2 wherein said management circuit implements the simple network management protocol and includes in-band management means for receiving in-band management data packets from either said first or second second network and carrying out any network management function identified by the data in said in-band management data packet, and further includes console command means for receiving management commands via a serial port or modem and carrying out said management commands.

4. The apparatus of claim 3 further comprising isolate means for selectively preventing any transfer of data packets from said first network to said second network, and wherein said isolate means includes means for directing any in-band management packets that arrive from either said first or second network to said management circuit for execution thereby even when said isolate means is active in preventing any data packet transfer between said networks.

5. An apparatus for coupling to first and second networks upon which data packets are being transmitted on one or more data transmission media, comprising:

a physical support for supporting electronic circuitry;

a memory mounted on said physical support for storing data packets to be transmitted on either said first or second network and for storing data packets received from either said first or second network;

a bridge circuit mounted on said physical support and comprising at least first and second network interface circuits coupled to said first and second networks, respectively, each said network having data transmission media, said first and second network interfaces for converting data packets to be transmitted on said first and/or second networks which have been retrieved from said memory into signals capable of propagating on said data transmission media of said first and/or second networks, said first and second networks each coupling a one or more computing machines together for data exchange, each said computing machine having a network address, said first and second network interfaces also for receiving signals transmitted by one or more of said computing machines via said data transmission media of said first or second networks and converting said signals into data packets for storage in said memory, each said data packet having a source network address which is the network address of the computing machine which transmitted said data packet and a destination network address which is the network address of the computing machine for which said data packet is bound, said bridge circuit for selectively forwarding a data packet received from a computing machine coupled to said first network to a computing machine coupled to said second network via said second network interface if the destination address of said data packet received from said computing machine coupled to said first network is the network address of a computing machine coupled to said second network or if said destination address of the received data packet is not known to be the network address of a computing machine coupled to either of said first or second networks, and for selectively forwarding a data packet received from a computing machine coupled to said second network to a computing machine coupled to said first network via said first network interface if the destination address of said data packet received from said computing machine coupled to said second network is the network address of a computing machine coupled to said first network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks;

and wherein at least one of said network interface circuits includes a repeater mounted on said physical support and which has one or more ports each of which is coupled to one of said data transmission media forming part of the network coupled to said network interface circuit which includes said repeater, said repeater for receiving data packets at one or more of said ports and automatically retransmitting said data packets out from the remaining ones of said one or more ports of said repeater thereby causing propagation of said data packets on all other data transmission media coupled to said repeater regardless of the destination network address of any particular data packet being retransmitted;

and further comprising management means mounted on said support structure and coupled to said bridge circuit and to said first and second network interface means, for receiving Simple Network Management Protocol commands and carrying out said commands, and

wherein said bridge circuit includes means for selective deactivation of bridging activity in a bypass mode which, when active, causes all data packets received from said first network to be retransmitted on said second network and which causes all data packets received from said second network to be retransmitted on said first network, and further comprising isolate means for selectively preventing any transfer of data packets from said first network to said second network and which prevents any transfer of data packets from said second network to said first network.

6. An apparatus for coupling to first and second networks upon which data packets are being transmitted on one or more data transmission media, comprising:

a physical support for supporting electronic circuitry;

a memory mounted on said physical support for storing data packets to be transmitted on either said first or second network and for storing data packets received from either said first or second network;

a bridge circuit mounted on said physical support and comprising at least first and second network interface circuits coupled to said first and second networks, respectively, each said network having data transmission media, said first and second network interfaces for converting data packets to be transmitted on said first and/or second networks which have been retrieved from said memory into signals capable of propagating on said data transmission media of said first and/or second networks, said first and second networks each coupling a one or more computing machines together for data exchange, each said computing machine having a network address, said first and second network interfaces also for receiving signals transmitted by one or more of said computing machines via said data transmission media of said first or second networks and converting said signals into data packets for storage in said memory, each said data packet having a source network address which is the network address of the computing machine which transmitted said data packet and a destination network address which is the network address of the computing machine for which said data packet is bound, said bridge circuit for selectively forwarding a data packet received from a computing machine coupled to said first network to a computing machine coupled to said second network via said second network interface if the destination address of said data packet received from said computing machine coupled to said first network is the network address of a computing machine coupled to said second network or if said destination address of the received data packet is not known to be the network address of a computing machine coupled to either of said first or second networks, and for selectively forwarding a data packet received from a computing machine coupled to said second network to a computing machine coupled to said first network via said first network interface if the destination address of said data packet received from said computing machine coupled to said second network is the network address of a computing machine coupled to said first network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks;

and wherein at least one of said network interface circuits includes a repeater mounted on said physical support and which has one or more ports each of which is coupled to one of said data transmission media forming part of the network coupled to said network interface circuit which includes said repeater, said repeater for receiving data packets at one or more of said ports and automatically retransmitting said data packets out from the remaining ones of said one or more ports of said repeater thereby causing propagation of said data packets on all other data transmission media coupled to said repeater regardless of the destination network address of any particular data packet being retransmitted;

and further comprising management means mounted on said support structure and coupled to said bridge circuit and to said first and second network interface means, for receiving Simple Network Management Protocol commands and carrying out said commands,

and wherein said repeater is part of said first network interface circuit and includes an Attachment Unit Interface port from which are transmitted said data packets being transmitted from the other of said ports of said repeater and which can also receive data packets, and further comprising switch means for selectively coupling said Attachment Unit Interface port to said second network interface circuit such that data packets transmitted from said Attachment Unit Interface port propagate on said second network and data packets propagating on said second network are received by said Attachment Unit Interface port and are retransmitted by said repeater on all physical data transmission media of said first network, and wherein said bridge circuit includes bypass means for setting said switch means such that said Attachment Unit Interface port is coupled to said second network in a bypass mode such that any data packet arriving at said Attachment Unit Interface from either of said first or second networks is automatically repeated on the other network, and wherein said management means includes means for receiving in-band management data packets from computing machines coupled to either said first network or second network and carrying out said commands, and

wherein said bridge circuit includes means for selective deactivation of bridging activity In a bypass mode which, when active, causes all data packets received from said first network to be retransmitted on said second network and which causes all data packets received from said second network to be retransmitted on said first network, and further comprising isolate means for selectively preventing any transfer of data packets from said first network to said second network and which prevents any transfer of data packets from said second network to said first network, and

wherein said management means comprises in-band management means for receiving in-band management data packets via either said first or second network interfaces from computing machines coupled to either said first or second network and carrying out any network management function identified by the data in said in-band management data packets, and further comprising a serial port interface circuit mounted to said support for coupling either to a modem, a terminal or a personal computer for receiving management commands, and wherein said management means further comprises console command means for receiving management commands via said serial port and carrying out said management commands.

7. An apparatus for coupling to first and second networks upon which data packets are being transmitted on one or more media segments, comprising:

a physical support for supporting electronic circuitry;

a memory for storing data packets to be transmitted on either said first or second network and for storing data packets received from either said first or second network;

a bridge circuit mounted on said physical support and comprising at least first and second network interface circuits coupled to said first and second networks, respectively, each said network having data transmission media, said first and second network interfaces for converting data packets to be transmitted on said first and/or second networks and retrieved from said memory into signals to propagate on said data transmission media of said first and/or second networks, said first and second networks each coupling one or more computing machines together for data exchange, each said computing machine having a network address which is a source network address if said computing machine is transmitting data as signals on either said first or second network and is a destination network address if said computing machine is receiving data as signals from either first or second network, said first and second network interfaces also for receiving signals transmitted by one or more of said computing machines via said data transmission media of said first or second networks and converting said signals into data packets for storage in said memory, each said data packet having a source network address indicating the computing machine which transmitted said data and a destination network address indicating the computing machine for which said data packet is bound, said bridge circuit for selectively forwarding a data packet received from a computing machine coupled to said first network to a computing machine coupled to said second network via said second network interface if the destination address of said data packet received from said computing machine coupled to said first network is the network address of a computing machine coupled to said second network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks, and for selectively forwarding a data packet received from a computing machine coupled to said second network to a computing machine coupled to said first network via said first network interface if the destination address of said data packet received from said computing machine coupled to said second network is the network address of a computing machine coupled to said first network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks;

and wherein at least one of said network interface circuits includes a repeater mounted on said physical support and which has one or more ports each of which is coupled to a media segment forming part of the network coupled to said network interface circuit which includes said repeater, said repeater for receiving data packets at one or more of said ports and automatically retransmitting said data packets out on at least one other of said one or more ports of said repeater regardless of the destination network address of any particular data packet being retransmitted; and

a management circuit coupled to said bridge circuit, said repeater(s) and said network interface circuits, for receiving and carrying out management commands, and

wherein said apparatus includes means coupled to said bridge circuit, said network interface circuit and said repeater(s) for implementing the national standard Internet Protocol defined by RFC 791, the Internet Control Message Protocol defined by RFC 792, the Address Resolution Protocol defined by RFC 826, and the Reverse Address Resolution Protocol defined by RFC 903 as these protocols were defined and published by the IETF at the time this application was filed, and

wherein each said repeater drives an attachment unit interface port and twenty-six or fewer media access units, and further comprising a bypass circuit for bypassing said bridge circuit such that any data packet arriving from either of said first or second networks is automatically transmitted on the other network via the network interface circuit and all media access units connected thereto in addition to being retransmitted via the network interface circuit of the network from which said data packet originated and substantially all media access units coupled thereto.

8. An apparatus for coupling to first and second networks upon which data packets are being transmitted on one or more media segments, comprising:

a physical support for supporting electronic circuitry;

a memory for storing data packets to be transmitted on either said first or second network and for storing data packets received from either said first or second network;

a bridge circuit mounted on said physical support and comprising at least first and second network interface circuits coupled to said first and second networks, respectively, each said network having data transmission media, said first and second network interfaces for converting data packets to be transmitted on said first and/or second networks and retrieved from said memory into signals to propagate on said data transmission media of said first and/or second networks, said first and second networks each coupling one or more computing machines together for data exchange, each said computing machine having a network address which is a source network address if said computing machine is transmitting data as signals on either said first or second network and is a destination network address if said computing machine is receiving data as signals from either first or second network, said first and second network interfaces also for receiving signals transmitted by one or more of said computing machines via said data transmission media of said first or second networks and converting said signals into data packets for storage in said memory, each said data packet having a source network address indicating the computing machine which transmitted said data and a destination network address indicating the computing machine for which said data packet is bound, said bridge circuit for selectively forwarding a data packet received from a computing machine coupled to said first network to a computing machine coupled to said second network via said second network interface if the destination address of said data packet received from said computing machine coupled to said first network is the network address of a computing machine coupled to said second network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks, and for selectively forwarding a data packet received from a computing machine coupled to said second network to a computing machine coupled to said first network via said first network interface if the destination address of said data packet received from said computing machine coupled to said second network is the network address of a computing machine coupled to said first network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks;

and wherein at least one of said network interface circuits includes a repeater mounted on said physical support and which has one or more ports each of which is coupled to a media segment forming part of the network coupled to said network interface circuit which includes said repeater, said repeater for receiving data packets at one or more of said ports and automatically retransmitting said data packets out on at least one other of said one or more ports of said repeater regardless of the destination network address of any particular data packet being retransmitted; and

a management circuit coupled to said bridge circuit, said repeater(s) and said network interface circuits, for receiving and carrying out management commands, and

wherein said management circuit implements the Simplified Network Management Protocol defined in national standard RFC 1157 and the User Datagram Protocol defined in national standard RFC 768 as these protocols were defined and published by the IETF at the time this application was filed. The apparatus of claim 40 further comprising isolate means for selectively preventing any transfer of data packets from said first network to said second network, and wherein said isolate means includes means for directing any in-band management packets that arrive from either said first or second network to said management circuit for execution thereby even when said isolate means is active in preventing any data packet transfer between said networks.

9. An apparatus for coupling to first and second networks upon which data packets are being transmitted on one or more data transmission media, comprising:

a physical support for supporting electronic circuitry;

a memory mounted on said physical support for storing data packets to be transmitted on either said first or second network and for storing data packets received from either said first or second network;

a bridge circuit mounted on said physical support and comprising at least first and second network interface circuits coupled to said first and second networks, respectively, each said network having data transmission media, said first and second network interfaces for converting data packets to be transmitted on said first and/or second networks which have been retrieved from said memory into signals capable of propagating on said data transmission media of said first and/or second networks, said first and second networks each coupling a one or more computing machines together for data exchange, each said computing machine having a network address, said first and second network interfaces also for receiving signals transmitted by one or more of said computing machines via said data transmission media of said first or second networks and converting said signals into data packets for storage in said memory, each said data packet having a source network address which is the network address of the computing machine which transmitted said data packet and a destination network address which is the network address of the computing machine for which said data packet is bound, said bridge circuit for selectively forwarding a data packet received from a computing machine coupled to said first network to a computing machine coupled to said second network via said second network interface if the destination address of said data packet received from said computing machine coupled to said first network is the network address of a computing machine coupled to said second network or if said destination address of the received data packet is not known to be the network address of a computing machine coupled to either of said first or second networks, and for selectively forwarding a data packet received from a computing machine coupled to said second network to a computing machine coupled to said first network via said first network interface if the destination address of said data packet received from said computing machine coupled to said second network is the network address of a computing machine coupled to said first network or if said destination address of the received data packet is not the network address of a computing machine coupled to either of said first or second networks;

and wherein at least one of said network interface circuits includes a repeater mounted on said physical support and which has one or more ports each of which is coupled to one of said data transmission media forming part of the network coupled to said network interface circuit which includes said repeater, said repeater for receiving data packets at one or more of said ports and automatically retransmitting said data packets out from the remaining ones of said one or more ports of said repeater thereby causing propagation of said data packets on all other data transmission media coupled to said repeater regardless of the destination network address of any particular data packet being retransmitted;

and further comprising management means mounted on said support structure and coupled to said bridge circuit and to said first and second network interface means, for receiving Simple Network Management Protocol commands and carrying out said commands,

and wherein said repeater is part of said first network interface circuit and includes an Attachment Unit Interface port from which are transmitted said data packets being transmitted from the other of said ports of said repeater and which can also receive data packets, and further comprising switch means for selectively coupling said Attachment Unit Interface port to said second network interface circuit such that data packets transmitted from said Attachment Unit Interface port propagate on said second network and data packets propagating on said second network are received by said Attachment Unit Interface port and are retransmitted by said repeater on all physical data transmission media of said first network, and wherein said bridge circuit includes bypass means for setting said switch means such that said Attachment Unit Interface port is coupled to said second network in a bypass mode such that any data packet arriving at said Attachment Unit Interface from either of said first or second networks is automatically repeated on the other network,

and wherein said management means includes means for receiving in-band management data packets from computing machines coupled to either said first network or second network and carrying out said commands.

10. The apparatus of claim 9 wherein said management means includes means for implementing the simple network management protocol and includes in-band management means for receiving in-band management data packets from either said first or second second network and carrying out any network management function identified by the data in said in-band management data packet, and further includes console command means for receiving management commands via a serial port or modem and carrying out said management commands.