Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
2000-02-23
2003-11-18
Kizou, Hassan (Department: 2662)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S422000, C370S428000, C709S238000
Reexamination Certificate
active
06650642
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a network relaying apparatus and a network relaying method, or in particular to a network relaying apparatus including a router of a computer network system which is capable of searching at high speed for a destination of a packet input and a network relaying search method.
Generally, in a network system, a network relaying apparatus such as a router or a bridge is used for connecting a plurality of networks. The router checks the destination address of a packet received from a network or a subnet connected, determines the destination of the packet, and transfers the packet to a network or a subnet which is connected with the destination router or host.
FIG. 13
is a diagram showing a configuration of a conventional network relaying apparatus. In
FIG. 13
, a router
100
includes a routing manager (RM)
110
, router buses
120
, network interfaces (NIF)
130
and ports
140
. Each port
140
is connected to an appropriate network
150
.
Each network interface
130
receives a packet from a network connected to the port
140
, and transmits the received packet through the router bus
120
to the routing manager
110
. The routing manager
110
includes a routing table for holding the routing information, and using this routing information, determines the network
150
of the destination from the address of the packet received, and transmits the packet to the network interface
130
of the port
140
connected to the network
150
. The network interface
130
that has received the packet from the routing manager
110
sends out the packet to the destination network
150
. The routing manager
110
updates and maintains the routing information held in the routing table based on the header information of the packet received, and has the function of overall management of the router
100
.
An explanation will be given of the route search process for searching for a port outputting the next address to which the packet is to be transferred upon receipt of the packet and outputting the packet. Normally, the route search uses a route search table (routing table) prepared from the component definition information and the information obtained by exchange between the routers. The routing table is for searching the information (next hop information) as to the output port, the next hop address and whether the network is directly connected or not with a set of the network address and the network mask length as a key.
As another conventional system, JP-A-05-199230(U.S. Pat. Ser. No. 5,434,863) discloses an internetwork system and a communication network system which can flexibly meet the size requirement of the network without adversely affecting the high-speed routing process. In these systems, a router manager and a plurality of routing accelerator modules are coupled to each other with a high-speed bus Also, each routing accelerator is connected with a plurality of independent communication ports. In these conventional systems, a plurality of the routing accelerators makes possible a high-speed routing and by adding the routing accelerators, the requirement for increasing the network size can be easily met.
SUMMARY OF THE INVENTION
In recent years, the demand has increased for the dynamic routing in which the relaying information for routing is dynamically generated, added, changed or deleted by recognizing the configuration of the network in operation. Specifically, the router requires the processing of the routing protocol (such as the Routing Information Protocol (RIP) or Open Shortest Path First (OSPF) included in TCP/IP protocols) for exchanging information on the network between the routers. Further, the processing of the network management protocol (such as Simple Network Management Protocol (SNMP) which is one of the TCP/IP protocols) for communication of the management information such as the performance of the router with a management master station on the network is performed unavoidably by the routing means in the prior art. This makes it impossible for the router to exhibit the relaying performance sufficiently. The conventional router, therefore, cannot easily meet the requirement of the high-speed lines such as the high-speed LAN (Local Area Network), the wide-band ISDN (Integrated Services Digital Network) and ATM (Asynchronous Transfer Mode) that have recently found practical applications.
Also, with the recent increase in the operating speed of the network, the data processing system used for the routers and bridges require a high processing speed of the network controller searching for a transfer destination route from a memory. Further, considering the processor contention for memory access, the conventional routers limit the number of network controllers to absorb the reduced performance caused by the memory access contention or, though low in cost effectiveness, unavoidably use a high-speed memory or a dual-port memory accessible from the processors or the network controller asynchronously. Also, the route search in the conventional router is carried out mainly in software, thereby making high speed execution of the routing process difficult.
An object of the present invention is to provide a network relaying apparatus and method for high speed routing while assuring a high communication quality (QoS), a high reliability and security.
Another object of the invention is to provide a network relaying apparatus and method for high speed packet routing and packet transfer by executing the hardware processing for each function block including a transfer engine and a search engine.
Still another object of the invention is to provide a network relaying apparatus and method for high-speed routing by dividing the routing process into the receiving process, the transmission process, the input search process and the output search process with required tables used independently of each other.
Yet another object of the invention is to provide a relaying apparatus and method for realizing a higher speed by executing each process by pipelining.
Other objects, features and advantages of the present invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings.
According to one aspect of the invention, here is provided a network relaying apparatus connecting a plurality of networks for outputting the packets input from the networks, to the next transfer destination based on the route information, comprising:
at least a network interface connected to the networks for controlling the interface with the networks;
at least a routing processor connected to one or a plurality of the network interfaces for routing the packets input from the network interfaces;
a routing manager for managing the internal components of the system; and
a connector for connecting the routing manager and each of a plurality of the routing processors;
wherein the routing processors each include:
a packet buffer for storing an input packet;
a high-speed readable and writable header memory accessible asynchronously with the packet buffer and adapted for storing the header information including the header and the internal header of the input packet;
a route table for storing the route information including the IP address of the next router corresponding to the destination internet protocol (IP) address;
an address search table for storing a media access control (MAC) address of the next router corresponding to the IP address of the next router;
a flow search table for storing the action corresponding to the reference conditions including the IP headers of the source and the destination;
a transfer engine for performing a receiving process for storing an input packet received from a network or the connector in the packet buffer, adding the internal header to the packet header and storing the resulting header information in the header memory, and a transmission process for reading the input packet from the packet buffer, producing an output packet from the input packet st
Aimoto Takeshi
Matsuyama Nobuhito
Sako Yoshihito
Sugai Kazuo
Tanabe Tomohiko
Hirachi, Ltd.
Kizou Hassan
Levitan Dimitry
Mattingly Stanger & Malur, P.C.
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