JPH10308762A - Router routing with physical address - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a router which perform routing by using setting through unnumbered setting even in an interface that is not point-to-point setting. SOLUTION: This router which connects different networks and performs routing of packets controls routing of packets by using the physical address of a gateway that is the entrance and exit of a network of a packet destination, a routing table which stores information about an interface at the time of connecting with the network and information stored in the routing table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a router using a physical address of a destination router when routing a packet between different networks.

[0002]

2. Description of the Related Art A router is a device for connecting different LANs (local area networks) in a network layer (layer 3) of an OSI (Open System Interconnection) reference model. Also, a router is sometimes called a gateway because it serves as a gateway for different networks.

[0005] A router generally has a routing table (path control information) as shown in FIG. 5 for routing a packet. The routing table shown in FIG. 5 includes the IP address (Internet Protocol address) of the destination terminal of the packet, the IP address of the router (gateway) provided at the gateway of the destination network, and other information. I have.
Conventionally, since gateways are managed by IP addresses, IP addresses are assigned to all interfaces of the router (e.g., gateways for information; Ethernet / ISDN (Integrated Services Digital Information Network) / dedicated line / serial).

[0004] However, an exception is Point to Point (IS
In the case of one-to-one connection using a DN / dedicated line / serial / telephone line, etc.), a method of not assigning an IP address to the interface by identifying the interface name (a method called Unnumbered (unnumbered))
Is becoming more common.

[0005]

However, in the conventional router described above, Poin such as a frame relay is used.
In an interface that is not t to Point (a plurality of partners are connected to one interface), it is necessary to set an IP address as before. Since the IP address is used to assign a global network address using only 32 bits of data, the IP address is now valuable. Therefore, a technology that does not consume it is useful.

The present invention has been made under such a background, and it is possible to make an interface which is not a point-to-point unnumbered, that is, not assign an IP address to an interface. The purpose is to provide a routing router.

[0007]

According to an aspect of the present invention, there is provided a router for connecting different networks and routing a packet.
Storage means for storing a physical address of another router serving as an entrance / exit of a network of a destination of a packet and information on an interface for connecting to the network; and a storage means for the other router stored in the storage means. Control means for controlling packet routing using a physical address and information on an interface corresponding to the physical address is provided.

The invention according to claim 2 is characterized in that an IP address is not assigned to another router serving as an entrance / exit of a destination network of the packet.

Further, the invention according to claim 3 is characterized in that the physical address of another router stored in the storage means is:
Information about an interface used to connect to the network forms static routing information indicating all routing information relating to packet routing or dynamic routing information which is automatically updated when routing a packet. It is characterized by being. Also,
The invention according to claim 4, wherein the medium interposed between the other routers is a frame relay network, and data assigned by the frame relay to specify a destination of a frame in which the physical address is multiplexed. It is a link connection identifier.

According to the above configuration, it is possible to designate a physical address to another router which is an entrance / exit of a destination network of a packet, and it is possible to perform routing by setting to Ununmbered even on an interface which is not a point-to-point. become able to.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining an embodiment of the present invention. In the example shown in FIG. 1, a frame relay network FR is used as a medium interposed between different networks. In FIG. 1, routers R1, R2, and R3 are connected to the frame relay network FR by one communication path. Each router R1,
R2 and R3 each have a network ID of 192.168.1.0/2
4, 192.168.2.0/24, 192.168.3.0/24, a local area network Ethernet1,
2 and 3 are connected respectively. Routers R1, R2, and R3 are:
Each frame composed of a plurality of packets has a DLCI (Data Link Connection) corresponding to the physical address of the router which is the gateway of the network on the partner (destination) side.
Identifier (abbreviation for data link identifier) and sends it out to the frame relay network FR. Frame relay network FR
Transmits each frame within the network based on the DLCI number, and transmits the frame to the corresponding router. DLC
I is used to identify a plurality of logical communication paths (data links) set on one physical line, and is a "logical address" when viewed from the line side, that is, from the physical layer. Although it can be said, from the viewpoint of the IP level, that is, the network layer, it can be considered as being equivalent to a “physical address”.

In the case shown in FIG. 1, in the router R1, the ID
When the destination is Ethernet 2 of 192.168.2.0/24
The CI is 16 and the DLCI is 17 when the destination is the Ethernet 3 having the ID of 192.168.3.0/24. Also, router R2
, When the destination is Ethernet 1 having an ID of 192.168.1.0/24, the DLCI is 16, and the ID is 192.168.3.0/24.
The DLCI is 17 when the destination is the Ethernet 3 of FIG.
Then, in the router R3, the Et having the ID of 192.168.1.0/24
When the destination is hernet 1, the DLCI is 17, and the ID is
When the destination is Ethernet 2 of 192.168.2.0/24
CI is 16. In this example, the frame relay network
It is assumed that the interface name on the FR side is PP1 and the interface name on the Ethernet side is LAN.

In general, there are two methods of setting "routing" in which a router distributes each packet to an appropriate network based on a network address such as an IP address of a partner, "static routing" and "dynamic routing". . The router holds a table of routing information (which destination packet should be passed to which router) to deliver the packet. How to set this table manually for all routes is called "static routing" (static routing)
"Dynamic routing" (dynamic routing) refers to a method of setting automatically by exchanging information between routers. Static routing and dynamic routing can be used together.

In the above configuration, when static routing is performed, a setting example of the router R1 according to the present invention is as follows.
It looks like this:

Ip pp route add net 192.168.2.0/24 dlci = 16 1 ip pp route add net 192.168.3.0/24 dlci = 17 1

In this case, the Ethernet having the ID of 192.168.2.0/24
For et2, the interface to it is PP1 and the router connected to the network
It sets that the number of the DLCI of R2 is 16. Router
No IP address is assigned to R2. Also,
Similarly, for the Ethernet 3 of 192.168.3.0/24, set that the interface is PP1 and the DLCI of the router R3 connected to the network is 17, and set the IP address for the router R3. Is not assigned.

On the other hand, when performing dynamic routing, a protocol for performing dynamic routing, for example, “RIP” (Routing) is sent to all routers.
Information Protocol, which is a type of protocol for performing dynamic routing). A routing table of the form shown in FIG. 2 is automatically generated in each router by dynamic routing. The routing table shown in FIG. 2 shows an example of a table generated by the router R1. In dynamic routing, each router
According to the RIP procedure, information such as "I have a route to 192.168.1.0/24" (in the case of router R1 in FIG. 1) is sent to each other router, and similar information is sent from each router. receive. In the table generated by router R1 based on this result, it is the ID of Ethernet 2.
Along with 192.168.2.0/24, information that the interface name is PP1 and information that the physical address (DLCI) allocated to the router R2 is 16 are generated. There is no IP address information on the table for this router R2. And the ID of Ethernet 3
For 192.168.3.0/24, information that the interface name is PP1 and information that the physical address (DLCI) assigned to the router R3 is 17 are generated. There is no IP address information for the router R3. For the Ethernet 1 ID 192.168.1.0/24, information that the interface name is LAN, and
It is assumed that information that the IP address of the interface on the Ethernet 1 side of the router R1 is 192.168.1.1 is set in advance.

Here, the procedure for the router to route the packet in the configuration example shown in FIG. 1 is as follows.

When there is only one destination with respect to the interface specified as the gateway (Point to
In the case of Point or when there is only one DLCI), a packet is thrown to the other party.

If the physical address is specified, throw it to the other party. This procedure is a feature of the present invention.

If you know the IP address,
The physical address is determined using a protocol such as ARP or InARP. Here, ARP is Address Resolu
This is an abbreviation of “tion Protocol” and is a protocol used on the Ethernet to associate a physical address (MAC address (medium connection control address) in Ethernet) with an IP address. InARP is Inverse
An abbreviation of Address Resolution Protocol, which is a protocol used on a frame relay to associate a frame relay logical address (physical address in the present invention) DLCI with an IP address.

Here, referring to the flowchart shown in FIG. 3, in the embodiment described with reference to FIG. 1, when the routing table as shown in FIG. An example will be specifically described. In order for a router to route a packet, it needs information about the interface to the gateway (the router that passes the packet) and the physical address. Here, it is assumed that interface information for each network is registered in advance in the routing control table, for example, statically. In the following description, the interface of the gateway is denoted by G_IF and the physical address of the gateway is denoted by G_IF.
G_PH, and sign the IP address of the gateway G_IP
Expressed by

Now, from Ethernet 1 to Ethernet 2 (192.168.
If a packet to 2.0 / 24) is generated, the router R1 that wants to send the packet searches the routing control table and obtains information about the gateway to Ethernet 2 (step S100). Normally, the gateway information listed in the routing table is the interface (LAN side or P
P1 or physical address (DLC for frame relay)
I) An IP address, but not all information is always known. Therefore, in step S110, it is determined whether an entry corresponding to the destination exists in the routing control table. If no entry exists, the process proceeds to step S115 to discard the packet. In this case, as shown in FIG.
Since the entry of exists, proceed to step S120,
It is determined whether or not the interface G_IF of the gateway is Point to Point. Here, if the interface is point-to-point (a dedicated line or ISDN)
Sends a packet to that interface (step S125), but in this case it is not a Point to Point,
Proceed to step S130.

In step S130, it is determined whether the destination of the packet is a broadcast. If the destination is a broadcast, the packet is thrown to all the physical addresses of the interface G_IF of the gateway (step S135). Since it is not a broadcast here, the process proceeds to step S140, and the interface of the gateway
A list of physical addresses for the G_IF is, for example, PVC (Parm).
Abbreviation for anent Virtual Circuit. Confirmation is made using a list of DLCIs obtained by the procedure of (fixed connection virtual circuit) state confirmation. As a result of the check, if there is only one physical address corresponding to the interface (if there is only one DLCI in the frame relay), a packet is thrown to the physical address (step S150 to step 155).
In this case, there is not one physical address, so step
Proceed to S160. In step S160, it is determined whether or not there is a physical address G_PH corresponding to the destination gateway. If not, the process proceeds to step S170. In this case, the information (DL) of the physical address G_PH is used as the destination gateway information.
CI = 16), the process proceeds to step S165, and a packet is thrown to the physical address G_PH corresponding to the gateway. By the above procedure, a packet (a frame including the packet in this case) is sent from the router R1 to the Ethernet 2.

On the other hand, as a result of the determination in step S160, the physical address G_PH for the interface G_IF of the gateway
If there is no IP address, it is determined in step S170 whether or not there is an IP address as information on the gateway. If there is no IP address, the physical address could not be determined by any method. Is discarded (step 180). Meanwhile, step S17
If it is determined in step 0 that there is an IP address, the process proceeds to step 190, where the IP address G_IP is converted to a physical address G_PH using ARP or InARP,
In step S195, a packet is thrown for the physical address G_PH converted, and the process ends.

It should be noted that the processing related to the routing based on the physical address in steps S160 and S165 does not necessarily need to be provided between the processing in step S150 and the processing in step S170, and is moved to the position from the processing in step S110 to the processing in step S170. It is possible. For example, step
S160 and S165 can be moved between steps S110 and S120.

Next, a configuration example of a router to which the present invention is applied will be described with reference to FIG. FIG. 4 is a block diagram showing the internal configuration of the router.
CPU 401, RAM 402, flash ROM 40 for storing processing procedures by CPU 401, programs for supporting various protocols, and various settings such as a path control table.
3. LAN control unit 404 that controls transmission and reception of packets to and from a LAN such as Ethernet; ISDN control unit 406 that interfaces with ISDN and frame relay and controls transmission and reception of packets or frames; Serial control units 408 for exchanging control signals for changing or the like are connected to each other. An input / output port 405 for connecting a LAN such as Ethernet is connected to the LAN control unit 404.
An input / output port 407 for connecting a communication path to an ISDN or a frame relay network is connected to the N control unit 406, and an input / output port 409 for serial connection is connected to the serial connection unit 408.

[0028]

As described above, according to the present invention, a network address is not allocated to an interface that conventionally requires both a physical address and a network address such as an IP address such as a frame relay. However, since direct routing can be performed using a physical address, the IP address can be saved as compared with the related art. Also, I
Although the design of the network tends to be complicated as the number of P addresses increases, there is also an advantage that the design / setting / management of the network becomes easier by reducing the number of IP addresses to be used.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a router according to an embodiment of the present invention.

FIG. 2 is a table showing an example of a routing control table (routing table) according to the present invention.

FIG. 3 is a flowchart illustrating an example of a processing procedure of a router according to the present invention.

FIG. 4 is a block diagram showing an example of the internal configuration of a router according to the present invention.

FIG. 5 is a table showing an example of a routing table of a conventional router.

[Explanation of symbols]

R1, R2, R3: router, FR: frame relay network, DLCI: data link identifier.

Claims (4)

[Claims] 1. A router for routing packets by connecting different networks, comprising: a physical address of another router serving as an entrance / exit of a destination network of the packet; information on an interface for connecting to the network; Storage means for storing packet information, and control means for controlling packet routing using the physical address of another router and information on an interface stored in the storage means. Router. 2. The router according to claim 1, wherein an IP address (Internet Protocol address) is not assigned to another router serving as an entrance / exit of the destination network of the packet. 3. A static route, wherein the physical address of another router stored in the storage means and information on an interface for connecting to the network are all route information on packet routing. 3. The router according to claim 1, wherein the router forms dynamic route selection information that is automatically updated when the selection information or the packet is routed. 4. A medium interposed between the other routers is a frame relay network, and a data link connection identifier assigned by a frame relay to specify a destination of a frame in which the physical address is multiplexed. The router according to claim 3, wherein