JP2000083051A - Packet relaying method and packet relaying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packet relaying device without causing any packet relay wait caused by a route calculation. SOLUTION: A route calculating part 1 preliminarily distributes a relaying basic information 3 being the basis of route calculation to a forwarding part 2 and the part 2 decides a relaying route by utilizing a preliminarily distributed relaying basic information 6 in the case of receiving a packet where a destination does not exist in a relaying determination information 26, relays the packet and then reports noncoincidence destination information of the packet to the route calculating part 1. The part 1 formally produces relaying determination information according to the relaying basic information 3 and the noncoincidence destination information and distributes it to the forwarding part 2. The part 2 relays the same destination packet that arrives next according to the distributed relation determination information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet relay method and a packet relay apparatus using information of a relay packet for selecting a relay route, and more particularly to a packet relay method and a packet relay apparatus suitable for multicast communication.

[0002]

2. Description of the Related Art In multicast communication, a packet transmitted from one computer (node) to a group is relayed to all of a plurality of computers (nodes) belonging to the group. FIG. 6 shows a conceptual diagram of the multicast communication. In FIG. 6, the packet transmitted by the computer (150) of the source S is transmitted to all the computers (15
1 to 157). A group is a unit of multicast communication, and the packet relay device holds a plurality of relay interfaces for one group. Basically, in multicast communication, the same packet is not relayed to the same computer and packet relay device. Therefore, the input interface of the packet relay device is always one interface. However, this is not the case at the route resolution stage of the routing protocol. In the multicast communication of FIG.
The packet relay device (router) R which has received the packet addressed to the group transmits the redundant route of multicast routing between R1 and R4 (158), between R4 and R3 (159),
Between R2 and R3 (160), between R6 and R9 (161), R
No packets (IP datagrams) are relayed between 8 and R9 (162). Further, for example, considering R7 (166), the data flow is set such that the source side (163) is upstream,
If the destination side is downstream (164, 165), the upstream packet relay device (167) relays to the computer (151) located upstream of one packet relay device. No need to relay to).

A conventional packet relay device for realizing multicast communication will be described with reference to FIG. The packet relay device has one or more physical or logical interfaces (here, 221 to 226), and is largely divided into a forwarding unit (235) and a route calculation unit (236). Generally, the route calculation unit (236) manages a plurality of forwarding units (235).

The forwarding section (235) has relay determination information (234) for relaying a specific packet, and has address information of a packet (227) received from one interface (221) and relay determination information (23).
The address part of 4) is compared, and the relay operation is performed according to the outgoing interface part of the entry of the matching relay determination information. Registered in the relay determination information (234) is a result of a route calculation performed by the route calculation unit (236) on a packet received in the past.

[0005] The route calculation unit (236) is a relay base consisting of source information (240) for confirming whether source information is received from a correct interface, and destination information (241) indicating a relay destination by a destination. It has information (220). Source information (24) of the relay basic information (220)
In the input interface section 0), an interface most suitable for the transmission source is registered. A group address is registered in the destination section of the destination information (241) of the relay basic information (220), and a plurality of optimal interfaces for relaying to the group are registered in the output interface section. The relay basic information (220) may be set by a user or may be resolved between devices by a routing protocol or the like.

In the packet relay device having such a configuration, in the case of the prior art, the forwarding unit (235)
Receives the packet (232) of the destination not registered in the relay determination information (234), registers the packet (232) in the relay waiting queue (237), and
6), the mismatch destination information (23) comprising the address information of the received packet (232) and the reception interface information.
Report 3). Upon receiving from the forwarding unit (235) the mismatch destination information (233) indicating that there is no address portion that matches the relay determination information (234), the route calculation unit (236) receives the mismatch destination information (233).
The source information and the destination information included in the address information in the field and the source information (240) and the destination information (241) of the relay basic information (220) in the route calculation unit are compared one entry at a time, and the validity of the receiving route is compared. And the relay destination is calculated, the incoming interface is deleted from the outgoing interface section of the destination information (241), and a new relay fixed information entry addition request (238) is issued to the forwarding section (235). The forwarding unit (235) includes a route calculation unit (2
36) Request to add relay confirmation information entry from (238)
Is newly stored as relay determination information (234) (242), and from the packets registered in the relay queue (237), the relay determination information (234) newly distributed by the route calculation unit (236) The packet (227) of the destination that matches the address portion (239) of the
34) (243), the interface (222, 2)
23, 224, 226) (228-23)
1). Then, the next arriving relay packet having the same destination is relayed according to the newly added relay determination information.

If new route determination information cannot be generated in the route calculation by the route calculator (236) for the mismatched destination information (233) reported from the forwarding unit (235), Calculation part (236)
Sends the relay confirmation information creation failure report to the forwarding unit (2
35). The forwarding unit (235), upon receiving the relay fixed information creation failure report, deletes the packet specified by the relay fixed information creation failure report from the relay queue (237).

Although not shown in the figure, the route calculation unit (236) manages the relay determination information (234), and sends the relay determination information to the forwarding unit (235) according to a change in the state of the network or the like. The change of (234) is also instructed.

[0009]

As described above, in the conventional packet relay device, when a packet of a destination not registered in the relay determination information of the forwarding unit is received, the forwarding unit places the received packet in a relay queue. Register, report the mismatched destination information to the route calculation unit,
Waiting for new relay confirmation information or generation failure notification from the route calculation unit, relaying or deleting the received packet causes a transmission delay of packet relay. For example, there is a problem that packets to be relayed are discarded. In addition, when receiving the mismatched destination information from the forwarding unit, the route calculation unit executes the route calculation one by one. Therefore, if new relay determination information cannot be generated, the route calculation of the packet that cannot be relayed from the beginning is performed. There is a problem of a redundant process such as performing in a calculation unit.

The present invention has been made in view of the above-described problems of the conventional packet relay apparatus, and has been developed in the event that a packet having a destination not registered in the relay determination information is received. It is an object of the present invention to prevent and reduce the occurrence of packet transmission delay and the occurrence of packet discard due to overflow of a relay queue, and the occurrence of redundant route calculation processing in a route calculation unit.

[0011]

In order to achieve the above object, according to the present invention, the order of processing of route calculation and packet relay is changed, and a relay route is determined based on basic relay information before route calculation. Then, by performing a route calculation after relaying the packet and generating relay determination information, the next and subsequent same destination packets are relayed according to the relay determination information.

More specifically, the route calculation unit distributes the basic relay information fixed by the user or the basic relay information generated based on the route information collected by communication between adjacent packet relay devices or computers to the forwarding unit in advance. When the forwarding unit receives a packet whose destination does not exist in the relay determination information, the forwarding unit calculates a relay route using the basic relay information distributed in advance from the route calculation unit, and places the packet in the relay waiting queue. Relay or discard without storing. At the same time, the forwarding unit reports the mismatch destination information including the received packet information whose destination does not exist in the relay determination information to the route calculation unit, and the route calculation unit checks the held relay basic information and the mismatch received from the forwarding unit. New relay decision information is formally created based on the received packet information of the destination information, and distributed to the forwarding unit. The next arrival same destination packet is relayed by the forwarding unit in accordance with the relay determination information distributed from the route calculation unit.

[0013] Thus, when a destination packet not registered in the relay determination information is received, packet relay delay due to route calculation and packet discard due to overflow of the relay waiting queue are eliminated, and packets that cannot be relayed are forwarded by the forwarding unit. Since it is discarded, there is no need to report to the route calculation unit, so that redundant processing can be reduced.

Further, in another configuration of the present invention, the forwarding route determined by the forwarding unit is temporarily registered in the forwarding unit as relay determination information, and the forwarding route corresponding to the mismatched destination information reported to the route calculation unit is registered. If the forwarding unit receives the same destination packet of the next arrival before the decision information is distributed from the route calculation unit, the forwarding unit relays according to the relay decision information temporarily registered in the forwarding unit. Thereby, the forwarding unit can delete the report of the redundant mismatched destination information to the route calculation unit, and the route calculation unit can delete the redundant route calculation based on the report of the redundant mismatched destination information.

The forwarding unit reports at least the first mismatched destination information to the route calculation unit, and the route calculation unit formalizes the relay determination information and distributes it to the forwarding unit. The consistency between the determined information and the relay determined information of the forwarding unit is guaranteed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram of a first embodiment of a packet relay device according to the present invention.
This packet relay device has six interfaces (11 to 16) as in FIG. 17, and is largely divided into a route calculation unit (1) for calculating a packet relay route and a forwarding unit (2) for relaying the packet. . The route calculation unit (1) and the forwarding unit (2) are preferably implemented by different processors in order to enable simultaneous operation of the route calculation and the relay process, but may be divided into separate task modules of a single processor. Good.

The route calculation unit (1) updates the relay basic information (3) on which the relay route is calculated, and determines the relay route of the specific packet which is the result of the route calculation using the relay basic information (3). It generates and manages the stored relay determination information, and registers and updates the relay determination information (26) and the relay basic information (6) in the forwarding unit (2). In this embodiment, the relay basic information (3) includes source information (4) for checking the validity of a receiving route of a received packet in the network and destination information (5) indicating a relay destination of the received packet. Consists of The protocol information (29) will be described later.
In general, the route calculation unit (1) manages a plurality of forwarding units (2), and in order to further improve the reliability, a duplex configuration of a working and a backup is adopted.

The forwarding unit (2) relays the received packet in accordance with the relay determination information (26). If there is no entry in the relay determination information (26) in which the source information and the destination information of the received packet match, The relay destination is calculated using the relay basic information (6) distributed in advance from the route calculation unit (1), and the packet is relayed. Thereafter, the fact that a packet that does not exist in the relay determination information (26) has been relayed is reported to the route calculation unit (1) as mismatched destination information (27). When the route calculation unit (1) issues to the forwarding unit (2) a relay confirmation information entry addition request (28) calculated and created from the mismatched destination information (27) and the basic relay information (3), the forwarding unit (2) Then, a new entry is added to the relay determination information (26) from the relay determination information entry addition request (28).

When the next and subsequent same destination packets are received,
The forwarding unit (2) relays the packet according to the newly added relay determination information. FIG. 2 illustrates this. Also, the forwarding unit (2)
If the relaying route cannot be determined by using the basic relay information (6), the packet is discarded. FIG. 3 illustrates this.

The search information of the relay determination information (26) and the relay basic information (3, 6) has source information and destination information, and includes a route calculation unit (1) and a forwarding unit (2).
Then, the route information is calculated by comparing the source information and the destination information of the received packet.

The relay determination information (26) and the relay basic information (3, 6) can register one or more outgoing interfaces with respect to one incoming interface entry of source information, and the forwarding unit (2) Multicast relay is realized by copying and transmitting one packet received from one incoming interface to another plurality of outgoing interfaces.

In the following, the present packet relay device will
(Internet Protocol) It is assumed that it is used as an IP router in a multicast communication network.

FIG. 5 shows a network system compatible with IP multicast, in which R1 to R6 (120 to 12).
5) is an IP multicast compatible router. A router is a device that relays an IP datagram that is a communication unit packet of the IP protocol. In the system of FIG. 5, S1 to S9 (126 to 134) are computers compatible with the IP multicast protocol, and are the sender and receiver of the IP datagram. G1 to G3 (135
137) indicate the communication range of the IP multicast communication, and G1 (135) indicates S1 (126) and S3 (12).
8) and S9 (134) belong to G2 (136).
(128), S4 (129), S8 (133), S9
(134) belongs, and G3 (137) belongs to S2 (12).
7), S5 (130), S6 (131), S7 (13
2) and S8 (133). In this system, G
1 (135) is sent to S1
(126), S3 (128), and the IP datagram relayed to S9 (134) and transmitted to G2 (136)
S3 (128), S4 (129), S8 (133), S
9 (134) and transmitted to G3 (137) are sent to S2 (127) and S5 (13).
0), S6 (131), S7 (132), S8 (13
It is relayed to 3). The router R1 (120) has six interfaces (11 to 16), and the interface a
(11) is router R2 (121), interface b
(12) is router R6 (125), interface c
(13) is router R4 (123), interface d
(14) is a computer S3 (128), interface e
(15) is the computer S4 (129), interface f
(16) is connected to the router R5 (124), respectively.

The multicast communication path information includes a method in which a user sets in advance each router, and a method in which information is exchanged between routers by a routing protocol and a multicast communication path is automatically calculated. here,
Routing protocol X and routing protocol Y
Suppose there are two multicast routing protocols:

FIGS. 7 and 8 illustrate the operation of the routing protocol X. The routing protocol X (9) refers to the router R1 (176) as shown in FIG.
Relays the IP datagram (170) received from one of the self-management interfaces to all self-management interfaces (171 to 173) except the interface that received the IP datagram (170). The router (174), whose interface does not belong to the destination group of the relayed IP datagram, has the source address and the IP datagram of the destination group sent to the router that relayed the IP datagram. Pruning request for rejection of relay (175)
Send After receiving the pruning request (175), the IP router (176) thereafter sets the IP datagram (1) having the rejected source address and destination group as shown in FIG.
80) is not relayed to the interface (181) that has received the pruning request.

FIGS. 9 and 10 explain the operation of the routing protocol Y. As shown in FIG. 9, the routing protocol Y (10) transmits a group registration request (194) containing the group information to a computer (190, 191) or a router (192, 193) desiring to relay an IP datagram of a certain group in advance. ~ 19
7) to the router (192, 193, 198).
The router (192, 193,
198) is the interface that has received the group registration request (194 to 197) and the group registration request (194 to 19).
The group information included in 7) is registered. Then, FIG.
As shown by 0, when an IP datagram (200) of a destination matching the group information registered thereafter is received,
Interface (201,
202), the IP datagram is transmitted to an interface other than the interface (203) that received the IP datagram.

FIG. 11 shows a header format of an IP datagram. In the multicast communication, the source address is stored in the source address field (210) of the IP datagram header, and the multicast group address is stored in the destination address field (211) of the IP datagram header. As the destination group address, a class D address is used to coexist with and distinguish from an existing (class A to C) IP destination address. Figure 12 shows the class D address format.
Shown in In FIG. 12, “1110” of the first 4 bits means the class D. Note that the first bit of class A is “0”, the first two bits of class B are “10”, and the class C is
The first three bits are “110”.

In the system shown in FIG. 5, the router R1 (1
20), the routing protocol X (9) is operating on the interface a (11), the interface b (12) and the interface c (13), and the interface d (14), the interface e (15) and the interface f ( 16), the routing protocol Y (10) is operating. Although the two protocols X and Y are different, the same group needs to be able to communicate with each other.

The packet relay device of the embodiment shown in FIG. 1 corresponds to the router R1 (120) in the network system shown in FIG. That is, in FIG. 1, the interfaces a, b, and c as shown in FIG.
The routing protocol X (9) operates on the (11, 12, 13) side network, and the interface d,
The routing protocol Y (10) operates on the network on the side of e, f (14, 15, 16). The route calculation unit (1) manages the protocol information for each interface as protocol information (29).

The route calculator (1) collects relay basic information (3) by exchanging information with a route calculator of an adjacent IP router by a routing protocol. At this time, a user may set network information by inputting a fixed value without using a routing protocol.

Here, the route calculation unit (1) registers the interface closest to the network in the transmission source information (4) of the basic relay information (3). In the case of the system of FIG. 5, the computer S1 (126) of the router R1 (120)
Can be relayed by the interface a (11) and the interface c (13), but the interface a (11) can be relayed by the router R2 (121) while the interface c (13) can be relayed. Router R2 (12
1), R3 (122), and R4 (123) arrive at the three-stage relay, and as shown in FIG. 1, the source part of the source information (4) is included in the input interface part of the S1 entry (17). The interface a (11) is registered, and all interfaces (a (11), b (12), and b (12), on which the routing protocol X (9) operates) are registered in the outgoing interface unit.
c (13)), all interfaces b (1) except the interface a (11) which is an input interface.
2) and c (13) are registered. The computer S5 in FIG.
As shown in (130), the computer S of the interface a (11) and the interface c (13) of the router R1 (120)
In the case where the distance to 5 (130) is the same for the two-stage relay, one of them is selected from information such as the address viewed from the router R1 (120). Here, the router R1 (12
The IP address of the interface (11) of the router R2 (121) connected to the interface a (11) of the router R0 (0) is the interface c (13) of the router R1 (120).
It is assumed that the IP address is smaller than the IP address of the interface (13) of the router R4 (123) connected to the router R4, and that the one with the smaller IP address is selected. Therefore, as shown in FIG. 1, the source part of the transmission source information (4) has the interface a in the input interface part of the entry (18) of S5.
(11) is registered, and interfaces b (12) and c (13) are registered in the outgoing interface.

From the above, the network of the routing protocol X (9) and the routing protocol Y
In order to enable the same group to communicate with each other in the network of (10), the routing protocol Y (1
0) IP received from network interface
The datagram is transmitted to all interfaces (11, 12, 1) of the network of the routing protocol X (9).
3) must be relayed. Therefore, all interfaces on which the routing protocol X (9) operates are extracted from the protocol X entry of the protocol information (29), and are added and registered in the registration interface section of the destination information (5).

In FIG. 1, the route calculation unit (1) generates relay basic information (3) from the collected source information (4) and destination information (5) and distributes it to the forwarding unit (2) (19). ). As a result, the relay basic information (3, 6) is the same in the route calculation unit (1) and the forwarding unit (2). In addition, the route calculation unit (1) detects a new transmission source by the routing protocol X (9), and receives a group participation request of the routing protocol Y (10).
Even when the relay basic information (3) is changed, the relay basic information (3) is redistributed to the forwarding unit (2) (1).
9) The relay basic information (3, 6) of the route calculation unit (1) and the forwarding unit (2) is always kept the same.

FIG. 4 is a flowchart of the operation when the forwarding unit (2) receives an IP datagram in the packet relay device of the first embodiment of the present invention shown in FIG. Hereinafter, the operation of the forwarding unit (2) of the first embodiment will be described in detail with reference to FIGS.

I received from interface a (11)
The source address and the destination group address contained in the IP header of the P datagram (25) are compared with the source address and the group address of the forwarding determination information (26) of the forwarding unit (2), one entry at a time, respectively ( Step 90). If the source address and the group address in the header of the IP datagram (25) match each other, the relay determination information (26)
If it exists (case 105), it is checked whether the incoming interface in the entry matches the interface (11) that received the IP datagram (step 101). If received IP datagram (25)
The source address and the group address in the IP header match the address part of the relay determination information (26) entry,
If the incoming interface of the entry is different from the receiving interface (11) of the IP datagram (case 106), the IP datagram is discarded (step 102). If there is an entry in the relay determination information (26) in which the source address, the group address, and the input interface match (case 115), the forwarding unit (2) performs one or more interfaces registered in the output interface unit of the entry. (Step 103). At this time, if two or more outgoing interfaces are registered, the IP datagram is copied and the same IP datagram is transmitted to two or more interfaces (12, 13, 14, and 16 in FIG. 1). At this time, the IP datagram header may be changed according to interface-specific information such as TTL. Also, the source address and the group address in the IP header of the received IP datagram (25) correspond to the relay determination information (26).
If the address does not match (case 104),
Source address of P datagram and basic relay information (6)
Are compared one by one (step 91). If there is a matching entry (case 108), the input interface (interface a (11)) of the entry and the IP datagram are compared. (2
5) receiving interface (interface a (1
1)) are compared (step 92). If the interfaces do not match (case 109), the received IP datagram (60) is discarded (100), as shown at 61 in FIG. If the interfaces match (case 110), the outgoing interface units (interfaces b (12) and c (13)) of the entry are extracted (step 93).

Further, the destination address of the IP datagram (25) is compared with the group part of the destination information part (8) of the relay basic information (6) (step 94), and if there is a matching entry (case 111), The registration interface section of the entry (interfaces a (11), b (12),
c (13), d (14), f (16)), and ORs with the outgoing interface unit extracted from the source information (7) of the previous relay basic information (6) (step 9).
5), delete the incoming interface (interface a (11)) of the IP datagram (step 96) and determine the outgoing interface (interface b (12), c)
(13), d (14), f (16)). If there is no entry that matches the group part of the destination information part (8) of the relay basic information (6) (case 112), only the outgoing interface part extracted from the source information of the previous relay basic information (6) Out interface.

In the comparison (91) between the source address of the IP datagram (25) and the address part of the source information (7) of the relay basic information (6), if no matching entry exists (case 107), No outgoing interface is set, and the group address of the IP datagram (25) is compared with the group part of the destination information section (8) of the relay basic information (6) (step 94), and if there is a matching entry (case 111). , Take out the registration interface part of the entry, and logically OR it (step 95)
Delete the datagram input interface (step 9
6) Determine the outgoing interface. If there is no entry matching the group part of the destination information part (8) of the relay basic information (6) (case 112), there is no outgoing interface here.

Here, the source information (7) of the relay basic information (6) and the destination information (8) are compared, but only the source information (7) of the relay basic information (6) is compared. Packet relay device and destination information (8) of relay basic information (6)
A packet relay device based on only comparison can also be realized. The packet relay apparatus by comparing only the transmission source information (7) of the relay basic information (6) performs the same operation (case 11) as the group mismatch of the destination information part (8) of the relay basic information (6) in the above example.
2), the packet relay apparatus by comparing only the destination information part (8) of the relay basic information (6), finds that the address part mismatch of the source information (7) of the relay basic information (6) in the above example The same operation (case 107) may be performed.

Next, it is determined whether or not the calculated outgoing interface exists (step 97). If one or more interfaces exist (case 114), the received IP datagram is transmitted to all the outgoing interfaces. (Step 98). If two or more interfaces are registered in the outgoing interface, the received IP datagram is copied, and the same I
The P datagram is transmitted (21 to 24 in FIG. 1). If no interface exists in the calculated outgoing interface (case 113), the received IP datagram is deleted (step 100).

If the outgoing interface has an interface (case 114) and the received IP datagram is transmitted in accordance with the outgoing interface using the relay basic information (6) (step 98), the forwarding unit (2) receives the received IP datagram. The source address of the gram (25), the group address, and the mismatched destination information (27) comprising the incoming interface are both reported to the route calculation unit (1) (step 99).

The flow chart of FIG. 4 is basically applicable to the processing in the route calculation unit (1) if the received ID datagram is replaced with the mismatched destination information. That is, the route calculation unit (1) compares the source address of the mismatched destination information (27) with the address portion of the source information (4) of the relay basic information (3) one entry at a time, and if there is a matching entry, (Case 108), the input interface (interface a (11)) of the entry and the input interface (interface a) of the mismatched destination information (27)
(11)) is compared. If the interfaces do not match (case 109), the mismatch destination information (27) is discarded. If the interface matches, the outgoing interface section of that entry (interface b (1
2), c (13)) is taken out. Further, the destination address of the non-match destination information (27) is compared with the group part of the destination information part (5) of the relay basic information (3), and if there is a matching entry (case 111), the registration interface part of that entry (case 111) Interfaces a (11), b (12),
c (13), d (14), f (16)), and the logical sum of the previous relay basic information (3) with the outgoing interface part extracted from the source information (4) is obtained, and the incoming interface (interface a (11)) and determine the outgoing interface (interfaces b (12), c)
(13), d (14), f (16)). If there is no entry that matches the group part of the destination information part (5) of the relay basic information (3) (case 112), the outgoing interface extracted from the source information (4) of the previous relay basic information (3) Only the section is the outgoing interface.

In the comparison between the source address of the mismatched destination information (27) and the address portion of the source information (4) of the relay basic information (3), if no matching entry exists (case 107), The group address of the information (27) is compared with the group part of the destination information part (5) of the relay basic information (3), and if there is a matching entry (Case 1)
11) Take out the registered interface part of the entry, take the logical sum with the outgoing interface part taken out from the source information (4) of the previous relay basic information (3), and delete the incoming interface.

Also in the route calculation section (1), the packet relay device by comparing only the source information (4) of the relay basic information (3) is used to determine the destination information section (3) of the relay basic information (3) in the above example. Performing the same operation as the group part mismatch of 5), the packet relay apparatus by comparing only the destination information part (5) of the relay basic information (3), transmits the source information of the relay basic information (6) in the above example. The same operation as in the case of the address part mismatch of 4) may be performed.

If there is one or more interfaces in the calculated outgoing interface, a request for adding a relay confirmation information entry (28) is made by the source address, group address, incoming interface, and outgoing interface of the mismatch destination information (27). Create and distribute to forwarding unit (2). If no interface exists in the calculated outgoing interface, a mismatch destination information notification (2
Discard 7).

The forwarding unit (2) registers the relay determination information entry (28) distributed from the route calculation unit (1) in the relay determination information (26).

The source of management of the relay determination information (26) is the route calculation unit (1), which detects a status change occurring in the pair of the source address and the group address and reflects the change in the relay determination information (26) accordingly. The distribution to the forwarding unit (2) is performed by the route calculation unit (1). This is a pruning request by the routing protocol X (9), a group participation request by the routing protocol Y (10), or the like.

In the forwarding unit (2),
As shown in FIG. 2, when an IP datagram (40) having the same source address and group address as the one relayed in the above processing arrives, one is added to the relay determination information (45) of the forwarding unit (2). And sends an IP datagram according to the outgoing interface (41 to 4).
4).

As described above, according to the first embodiment of FIG. 1, when the forwarding unit receives a packet of an unregistered destination in the relay determination information, the forwarding unit reports the packet to the route calculation unit (1), and then performs the route calculation. Before the unit (1) distributes the relay determination information entry (28) to the forwarding unit (2) and before the forwarding unit (2) adds the distributed relay determination information entry (28) to the relay determination information (26), After the received frame is relayed to the optimum interface, the route calculation unit (1) can formally create the relay determination information (26).

Next, a second embodiment of the present invention will be described. In FIG. 1, the forwarding unit (2) reports mismatch destination information (27) to the route calculation unit (1),
The route calculation unit (1) issues a request to add a relay confirmation information entry (2
8) to the forwarding unit (2), and a certain time or more is required until the forwarding unit (2) adds a new entry to the relay determination information (26). During this time, the forwarding unit (2) may receive the same destination packet. In this case, the forwarding unit (2) calculates the relay destination again using the relay basic information (6) since there is no information for relaying the packet in the relay determination information (234), and relays the packet. Then, the mismatch destination information (27) is reported to the route calculation unit. Along with this, the route calculation unit (1) again generates redundant processing such as creation and issuance of the relay determination information entry addition request (28). In the second embodiment, these redundant processes are deleted.

FIG. 13 is a functional block diagram of a second embodiment of the packet relay device according to the present invention. 13 differs from FIG. 1 in that a temporary entry registration (244) is added to the relay determination information (26) in the forwarding unit (2), and the rest is the same as FIG. The route calculation unit (1) and the forwarding unit (2)
The configuration may be either an independent processor or an independent task module of the same processor, which is the same as in the first embodiment.

FIG. 14 is a diagram showing the packet relay by the temporary entry of the relay determination information, and FIG. 15 is a diagram showing that the temporary entry of the relay determination information is updated by the relay determination information entry addition request. FIG. 16 is a flowchart of the operation when the forwarding unit (2) receives the IP datagram, similarly to FIG. FIG. 16 differs from FIG. 4 in that a process of registering a temporary entry in the relay determination information is added, and the rest is the same as FIG.

The operation of the forwarding unit (2) according to the second embodiment will now be described with reference to FIGS.
This will be described in detail in comparison with. In FIG. 4, when the source address and the group address in the IP header of the received IP datagram (25) do not match the address part of the relay confirmation information (26) (case 104), the calculated output is performed as a subsequent process. It is determined whether an interface exists (step 97), and if one or more interfaces exist (case 114), it is determined that the received IP datagram is transmitted to all the outgoing interfaces (step 98).

On the other hand, in FIG. 16, it is determined whether or not the calculated output interface exists (step 97). If one or more interfaces exist (case 114),
As shown in FIG. 13, a temporary entry is registered (244) in the relay determination information (26) (step 247), and the received IP datagram is transmitted to all outgoing interfaces (step 98). Here, the entry registered in the relay determination information (26) is an entry created based on the source address, destination address, incoming interface, and outgoing interface calculated in step 96 of the IP datagram (25).

As described above, in the second embodiment, a temporary entry is registered in the relay determination information (26) (step 24).
7) As a result, as shown in FIG. 14, when the forwarding unit (2) receives the next and subsequent same destination packets before the route calculation unit (1) issues the relay determination information entry addition request (28). , The tentative entry (246) in the header of the IP datagram (40) in which the source address and the group address respectively match is the relay determination information (2).
45) (case 105), and the input interface in the temporary entry (246) is
The process (step 101) of checking whether the datagram matches the interface (11) that received the datagram is continued. That is, the received IP datagram (4
If the source address and the group address in the IP header 0) do not match the address part of the relay determination information (245) (case 104), the process is not executed. For this reason, from the processing (step 91) in which the source address of the IP datagram and the address part of the source information (7) of the relay basic information (6) are compared one by one (step 91), the forwarding part (2) sets the mismatch destination information (27). ) To the route calculation unit (1) (step 99) will not occur again.

FIG. 15 shows that, after the route calculation unit (1) has formally issued the relay determination information entry addition request (28), the forwarding unit (2) sets the relay determination information (245) shown in FIG. This indicates that the temporary entry (246) in the middle has been updated in accordance with the relay confirmation information entry addition request (28). The reason why the entry temporarily registered by the forwarding unit (2) is a temporary entry (246) is that, as shown in FIG. 15, after the route calculation unit (1) issues a relay determination information entry addition request (28). , The forwarding unit (2) and the route calculation unit (1) transmit the relay decision information (2
45) to formally match the entry (2) in the relay determination information (245).
46) is updated.

Along with the processing of the forwarding unit (2) as described above, the route calculation unit (1) does not report the mismatched destination information (27) due to the next and subsequent same destination packets, so that a redundant relay decision is made. The process of creating the information entry addition request (28) is deleted.

Although the embodiment of the present invention has been described above, the relay basic information (3) and the relay decision information (26) are stored in the common memory which can be independently accessed by the route calculation unit (1) and the forwarding unit (2). It may be stored in a device. In this case, there is no need for the route calculation unit (1) to distribute the relay basic information (6) to the forwarding unit (2) in advance, and the forwarding unit (2) uses the relay basic information (3) stored in the memory device. ) Can be used to determine the relay route.

In the embodiment shown in FIGS. 1 and 13, the relay basic information (3, 6) is composed of the destination information (5, 8) and the source information (4, 7). drinking places,
It is optional to use only the source information. This allows
The packet relay device can construct a network that needs to collect only destination information and only source information. Further, if the relay basic information is composed of the destination information and the source information as in the embodiment of FIGS. 1 and 13, a packet relay device capable of mutually relaying these networks can be realized.

[0059]

As described in detail above, according to the present invention,
By changing the order of the route calculation process and the packet relay process in the communication unit that performs the route calculation from the received packet information, it is possible to realize a packet relay device that does not cause a packet relay wait state in the forwarding unit. Specifically, the delay of the packet relay due to the calculation waiting of the route calculation unit is reduced, and when the packet of the destination not registered in the relay determination information is received, the forwarding unit determines whether the packet can be relayed, Redundancy processing is deleted by not reporting unrelayable packets to the route calculation unit, and from the relay wait queue that occurs when the route calculation unit cannot create relay decision information by not causing the forwarding unit to wait for packet relay. And a packet relay device in which packet discard at the time of congestion caused by the finite queue of relay waiting packets after being reported to the route calculation unit is reduced.

By realizing the functions of the path calculation unit and the forwarding unit by different processors,
It is possible to perform a route calculation and a relay operation physically at the same time, and to realize a packet relay device having a forwarding function with less delay than before.

Further, if the path calculation unit and the forwarding unit are separated into different task modules of a single processor, the same effect can be obtained, though not so much when different processors are used depending on the processing priority and the processing order. further,
A packet relay device that is less expensive than a packet relay device using different processors can be realized.

Further, when the functions of the route calculating unit and the forwarding unit are separated, the route calculating unit receives the same next destination packet during the calculation during the calculation. Although this occurs in the device, a packet relay device that does not perform the recalculation processing of the redundant route can also be realized by temporarily registering the relay determination information in the forwarding unit.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of an embodiment of a packet relay device according to the present invention.

FIG. 2 is a diagram illustrating packet relay based on relay determination information.

FIG. 3 is a diagram illustrating packet discarding due to reception interface mismatch.

FIG. 4 is a flowchart of the operation of the forwarding unit when receiving an IP datagram in the packet relay device according to an embodiment of the present invention;

FIG. 5 is an overall view of a network system according to an embodiment of the present invention.

FIG. 6 is a conceptual diagram of multicast communication.

FIG. 7 is a diagram showing an operation 1 of the routing protocol X.

FIG. 8 is a diagram showing an operation 2 of the routing protocol X.

FIG. 9 is a diagram showing an operation 1 of the routing protocol Y.

FIG. 10 is a diagram showing an operation 2 of the routing protocol Y.

FIG. 11 is a diagram showing a header format of an IP datagram.

FIG. 12 is a diagram showing a multicast group address format.

FIG. 13 is a functional block diagram of another embodiment of the present invention in which a forwarding section adds a temporary entry to relay determination information.

FIG. 14 is a diagram illustrating packet relay using a temporary entry of relay determination information.

FIG. 15 is a diagram showing that a temporary entry of relay determination information is updated by a relay determination information entry addition request.

FIG. 16 is a flowchart of the operation of the forwarding unit when receiving a trigger of receiving an IP datagram according to another embodiment of the present invention, in which the forwarding unit adds a temporary entry to the relay determination information.

FIG. 17 is a functional block diagram of a conventional packet relay device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Route calculation part 2 Forwarding part 3 Basic relay information of route calculation part 4 Source information of basic relay information of route calculation part 5 Destination information of basic relay information of route calculation part 6 Basic relay information of forwarding part 7 Relay of forwarding part Source information of basic information 8 Destination information of basic relay information of forwarding section 9 Protocol X 10 Protocol Y 11 to 16 Interfaces a to f 19 Distribution of basic relay information 25 Processing packet of forwarding section 26 Relay determination information of forwarding section 27 Unmatched destination information 28 Relay fixed information entry addition request 29 Protocol information of route calculation unit 45 Updated relay fixed information 244 Temporary entry registration of relay fixed information 245 Relay fixed information registered with temporary entry 246 Temporary entry

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Sekino 1 Horiyamashita, Hadano-shi, Kanagawa Prefecture Inside Nichi Information Technology Co., Ltd. (72) Inventor Kuzen Hayashi 810 Shimo-Imaizumi, Ebina-shi, Kanagawa Pref., Hitachi, Ltd.Server Development Division (72) Inventor Shigeki Morimoto 810 Shimo-Imaizumi, Ebina-shi, Kanagawa Pref. 72) Inventor Yoshito Sako 810 Shimo-Imaizumi, Ebina-shi, Kanagawa Prefecture Inside the server development headquarters of Hitachi, Ltd.

Claims (3)

[Claims] 1. A route is calculated based on information of a received packet and relay basic information which is a basis of a route calculation stored therein.
In a packet relay method of generating relay determination information for relaying a specific packet and relaying a packet based on the generated relay determination information, a relay route is determined based on relay basic information before calculating a route, A packet relay method comprising: performing a route calculation by relaying a packet; generating relay determination information; and relaying a subsequent same destination packet in accordance with the relay determination information. 2. The method of claim 1, wherein one or more physical or logical interfaces and a packet received from an interface are
A forwarding unit that relays according to registered relay determination information for relaying a specific packet, and a route that generates a relay determination information by calculating a route based on the packet information and the relay basic information that is the basis of the held route calculation A packet relay device comprising a calculation unit, when the forwarding unit receives a packet of a destination not registered in the relay determination information, calculates a relay route from the relay basic information and relays the packet, and Report the packet information to the route calculation unit.The route calculation unit generates new relay decision information based on the packet information reported from the forwarding unit and the relay basic information, and registers it as the relay decision information for the next and subsequent same destination packets. A packet relay device. 3. The method of claim 1, wherein one or more physical or logical interfaces and a packet received from an interface are
A forwarding unit that relays according to registered relay determination information for relaying a specific packet, and a route that generates a relay determination information by calculating a route based on the packet information and the relay basic information that is the basis of the held route calculation In a packet relay device comprising a calculation unit, when receiving a packet of a destination not registered in the relay determination information, the forwarding unit calculates a relay route from the relay basic information and changes the relay route to the next and subsequent packets. Register as temporary relay decision information of the same destination packet, relay the packet, and report the information of the packet to the route calculation unit. The route calculation unit transmits the packet information and relay basic information reported from the forwarding unit. To generate new relay determination information and register it as relay determination information of the same destination packet.
A packet relay device characterized by the above-mentioned.