Network relaying apparatus and network relaying method

• US 6,683,885 B1
• Filed: 02/23/2000
• Issued: 01/27/2004
• Est. Priority Date: 02/24/1999
• Status: Expired due to Term

• Current Assignee: Alaxala Networks Corporation (Fortinet Inc.)
• Original Assignee: Hitachi Information Technology Co. Ltd. (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Aimoto, Takeshi, Matsuyama, Nobuhito, Yazaki, Takeki, Sugai, Kazuo, Sako, Yoshihito, Tanabe, Tomohiko
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Levitan, D
• Application Number:
  US09/511,798
• Time in Patent Office: 1,434 Days
• Field of Search: 370/362, 370/389, 370/392, 370/395, 370/422, 370/423, 370/428, 709/238
• US Class Current: 370/423
• CPC Class Codes: H04L 2012/5618 Bridges, gateways [GW] or interworking units [IWU]
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/583 Stackable routers
• CPC Class Codes: H04L 45/60 Router architectures
• CPC Class Codes: H04L 49/205 Quality of Service based
• CPC Class Codes: H04L 49/254 Centralised controller, i.e. arbitration or scheduling
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/3063 Pipelined operation
• CPC Class Codes: H04L 49/309 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/9042 Separate storage for different parts of the packet, e.g. header and payload

Abstract

A network relaying apparatus and a network relaying method for securing a high communication quality (QoS), a high reliability and security. A transfer engine stores the packets received through at least a network interface in a packet buffer, and the header information in a header RAM. A search engine searches for the transfer control information such as the destination information and the action information based on the header information, and writes them in the header RAM. The transfer engine prepares an output packet based on the information stored in the packet buffer and the header RAM, and outputs the output packet to the destination. A switch switches the output packet to the routing processor of the destination. Each header RAM is asynchronously accessible independently of the packet buffer and suppresses the competition for access between the transfer engine and the search engine.

Claims

1. A network relaying apparatus connecting a plurality of networks for transferring packets input from the networks to the next destination based on route information, comprising:

a plurality of network interfaces connected to the networks for controlling the interface with the networks;

a plurality of routing processors;

a routing manager for managing the internal parts of the apparatus; and

a connector for connecting the routing manager and a said plurality of the routing processors respectively;

each of said plurality of routing processors comprising;

a packet buffer storing an overall input packet including a header and data;

a fast readable and writable header memory accessible to said packet buffer asynchronously therewith, and storing header information including the header of the input packet and an internal header;

a transfer engine performing a receiving processing and a transmitting processing, said receiving processing including storing the input packet received from the network or said connector to said packet buffer and adding the internal header to the packet header to produce header information and storing the produced header information in said header memory, and said transmitting processing including reading out the input packet from said packet buffer, producing an output packet from said input packet stored in said packet buffer and the header information stored in said header memory and outputting the output packet to said connector or said network;

a search engine searching a transfer destination based on the header information stored in said header memory and writing transfer destination information thus searched into the internal header stored in said header memory;

wherein the network interface outputs the packets input from the networks to a first routing processor connected with the network interface;

wherein a transfer engine of the first routing processor stores the input packets in a packet buffer and the header information on the input packets in a header memory;

wherein a search engine of the first routing processor searches for the destination of the input packets stored in the packet buffer based on the header information stored in the header memory and stores the destination information in the header memory;

wherein said transfer engine of the first routing processor produces an output packet from the input packet stored in the packet buffer and the header information stored in the header memory and

wherein outputs the output packet to the connector when the searched route to the destination is passed through a second routing processor; and

wherein the connector transmits the output packet from the first routing processor to the second routing processor of the searched destination, based on the destination information included in the internal header of the output packet.

2. A network relaying apparatus according to claim 1,

wherein said transfer engine of said first routing processor, when the route to the searched destination is passed through said first routing processor, applies an output packet to the port connected to said route of said network interface.

3. A network relaying apparatus according to claim 1, wherein:

said transfer engine of said second routing processor stores the input packet from said connector in a packet buffer and the header information on said input packet in a header memory;

said transfer engine of said second routing processor searches for the destination of the input packet stored in said packet buffer based on the header information stored in said header memory; and

said transfer engine of said second routing processor prepares an output packet from the input packet stored in said packet buffer and the header information stored in said header memory, and output the output packet to the port connected to said route of the network interface connected to the first routing processor.

4. A network relaying apparatus according to claim 1, wherein said transfer engine and said search engine of said routing processor are constructed in hardware independently from each other.

5. A network relaying apparatus according to claim 1, wherein said routing processor searches for a plurality of routes as destinations and multicasts the output packets to the routes searched.

6. A network relaying method for a network relaying apparatus comprising network interfaces connected to networks, routing processors for routing packets input from the network interfaces, a routing manager for managing internal parts of the apparatus, a connector for connecting a plurality of the routing processors, and means for outputting the packets input from the networks to the destination, comprising the steps of;

causing a first network interface to output the packets input from the network to a first routing processor connected with the first network interface;

causing a transfer engine of a first routing processor to store overall input packets in a packet buffer and header information on the input packet and internal header information in a high-speed readable and writable header memory independent of the packet buffer;

causing a search engine of a first routing processor to access the header memory and search for a destination of the input packet stored in the packet buffer based on the stored header information;

causing said search engine of the first routing processor to write the searched destination information into said header memory, as an internal header;

causing the transfer engine of the first routing processor to produce an output packet from the input packet stored in the packet buffer and the header information and the internal header information stored in the header memory;

causing the transfer engine of the first routing processor to output the output packet to the connector in the case where the route to the searched destination passes through a second routing processor; and

causing the connector to transmit the output packet input from the first routing processor to the second routing processor based on transfer destination information contained in the internal header of said output packet.

7. A network relaying apparatus connected with a plurality of networks for transferring packets input from the networks to the next destination based on route information, comprising:

a plurality of network interfaces connected to the networks for transmitting and receiving to and from said networks packets composed of a header and data;

a plurality of routing processors connected to one or a plurality of network interfaces for routing the packets input from the network interfaces;

a routing manager for managing the internal parts of the apparatus; and

a connector for connecting the routing manager and said plurality of the routing processors, respectively;

each of said plurality of routing processors comprising;

a packet buffer storing an overall input packet;

a header memory accessible to said packet buffer asynchronously therewith and storing header information including the header of the input packet and an internal header;

a transfer engine storing a packet input from said network interface or said connector in said packet buffer, storing the header of the input packet and said internal header in said header memory, as header information, producing an output packet from the input packet stored in said packet buffer and the header information stored in said header memory, and outputting the produced output packet to said connector or said network interface; and

a search engine searching a transfer destination based on the header information stored in said header memory and writing transfer destination information thus searched as part of the internal header in said header memory;

wherein the connector transmits the output packet from said transfer engine of the routing processor to any of the routing processors based on the destination information included in the internal header of the output packet.

8. A network relaying apparatus according to claim 7, wherein said routing processor further comprises a route memory storing routing information,

in response to inputting of a packet from said network interface, said search engine reads out a destination IP address from the header stored in said header memory, searches said routing information of said route memory using said destination IP address, and extracts said transfer destination information including an IP address of the transfer destination.

9. A network relaying apparatus according to claim 8, wherein said routing processor further comprises an address memory storing a plurality of IP addresses and a plurality of MAC addresses that are correlated with each other,

in response to inputting of a packet from said connector, said search engine reads out an IP address of a transfer destination from the internal header stored in said header memory, and searches a MAC address correlated with an IP address stored in said transfer destination.

10. A network relaying apparatus system according to claim 8, wherein said routing manager distributes said routing information to each of said routing processors, and

said each routing processor stores said distributed routing information in said route memory.