JP3471136B2 - Control information transfer method and node device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication node device for transmitting and receiving user information and various control information and a control information transfer method.

[0002]

2. Description of the Related Art When a packet communication node such as a router or a host connected to a virtual connection type network transfers a packet to a next-stage node, the virtual connection up to the next-stage node is set to a predetermined connection setting protocol. Based on the setting, packet transfer is performed using the set virtual connection.

Packets exchanged between the transmitting and receiving terminals include not only communication information between actual terminal applications, but also various control messages including a message for resource reservation for requesting a desired communication quality. Exists. In the current router connected to the virtual connection type network, if the destination node address of the packet is the same, regardless of whether it is a control message or actual communication information, the same transfer processing is performed on the packet. It is applied to. That is, in the case of transfer to a virtual connection type network, the routing table is referenced based on the destination node address of the packet, and the result is the same virtual connection regardless of whether it is a control message or communication information. A packet is transmitted to the packet.

[0004]

When the control information and the actual communication information are transferred on the same virtual connection, the following problems occur.・ Internet draft draft-katsube-router-atm-o
Extension of router architecture as described in verview-00.txt (Direct connection of input virtual connection and output virtual connection (without network layer processing) to speed up transfer processing) If you do, the control message cannot be recognized by the router.

In this case, of the frames (or cells) received from one virtual connection, a mechanism for extracting only those corresponding to the control message packet and processing the contents is provided, and other communication information frames (Or cell) needs to be able to be transferred without packet level processing,
Achieving this will increase the cost of the communication node.

When an abnormality occurs in the virtual connection that is transferring communication information, not only the communication information but also the control message is not transferred, so that it may not be possible to cope with the alternative route selection in the event of an abnormality. is there. -One message cannot control multiple related virtual connections.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems, and relates to a packet having the same destination address, a control information packet (control packet) and a user communication information packet (user Data packet) is transferred using a different virtual connection.

A first aspect of the present invention is a control information transfer method when a packet communication node which is connected to a virtual connection type network and transmits / receives user data and various control packets transmits a packet group to a next stage node. , An output virtual connection for transmitting the user data packet and an identifier in the packet.
May be set respectively and an output virtual connection for transmitting the control packet, based on the information and protocol identification information of the destination node address field included in a packet to be transmitted, the control packet with a given destination node address, It is characterized in that control is performed so that the user data packet having the same destination node address is transmitted by an output virtual connection different from the output virtual connection.

The first aspect of the present invention can also be understood as a node device having the following means. The node device is connected to a virtual connection type network, packet transmitting means for transmitting user data and various control packets, a user data packet having the same destination node address, and a control packet identified by an identifier in the packet. Storage means in which the correspondence relationship is stored so that they can be transmitted by different output virtual connections, and the storage means is referred to based on the information of the destination node address field and the protocol identification information included in the packet to be transmitted. A packet for transferring a packet while determining an output interface to the node and an output virtual connection to the next-stage node and instructing the packet transmitting means of the determined output interface to transmit the packet through the determined output virtual connection. Equipped with analysis and transfer means And wherein the door.

The output virtual connection may be a point-point connection or a point-multipoint connection. Also, when the user data packet and the control packet have the same destination node address, the output virtual connection used for transmitting the user data packet and the output virtual connection used for transmitting the control packet have the same next-stage node. The virtual connection may be a virtual connection having a different entity, and the route between the transmitting node and the next-stage node may be the same or different.

Further, the above-mentioned node is assumed to be a router or a host capable of network layer (eg, IP (Internet Protocol)) processing. According to the first aspect of the present invention, since the output virtual connection is determined based on the protocol identification information included in the packet to be transmitted, the control packet is the output virtual connection for transmitting the user data packet having the same destination node address. Can be sent on a different output virtual connection.

According to a second aspect of the present invention, a packet communication node connecting to a virtual connection type network and transmitting and receiving user data and various control packets sends a packet group whose destination node address is a multicast address to the multicast group. In the control information transfer method when transmitting to the corresponding next-stage node group, a plurality of output virtual connections for transmitting a user data packet to each of the next-stage node groups corresponding to a plurality of multicast groups, and an identifier in the packet Identified by
The control packet may be set respectively and one output virtual connection for transmitting collectively the next stage nodes corresponding to the plurality of multicast groups, information of the destination multicast address field included in the multicast packet to be transmitted and Based on the protocol identification information, the control packet having a predetermined destination multicast address is controlled to be transmitted by the one output virtual connection different from the output virtual connection transmitting the user data packet having the same destination multicast address. Characterize.

The second invention of the present invention can also be understood as a node device having the following means. The node device according to claim 5 is a packet transmission means for connecting to a virtual connection type network and transmitting user data and various control packets, and a user data packet whose destination node address is a multicast address falls under the multicast group. at the next hop node different from the output virtual connection for transmitting to the group, a plurality of multicast groups in the packet together to the next nodes corresponding possible transmission output virtual connection to the packet
The storage means stores the correspondence so that the control packet identified by the identifier in the packet can be transmitted, and refers to the storage means based on the information of the destination multicast address field and the protocol identification information included in the packet to be transmitted. , Determining an output interface to the next-stage node and an output virtual connection to the next-stage node, and instructing the packet transmitting means of the determined output interface to transmit the packet through the determined output virtual connection, And a packet analysis / transfer means for transferring.

Here, the output virtual connection may be a point-multipoint connection, or a combination of a point-point connection to the multicast server and a point-multipoint connection from the multicast server to the next stage node group. It may be. Also, the user data packet is transmitted using a point-multipoint connection set for each multicast group (the end of one connection is the next-stage node group corresponding to one multicast group). Is transmitted using one point-multipoint connection (the end of the connection includes all of the next stage node groups corresponding to any of a plurality of multicast groups). That is, the user data packet and the control packet use different output virtual connections with different next-stage node groups.

Further, the above node is assumed to be a router or host capable of network layer (eg IP) processing. According to the second aspect of the present invention, since the output virtual connection is determined based on the information of the destination multicast address field and the protocol identification information included in the packet to be transmitted, the next stage corresponding to any one of the plurality of multicast groups. Unlike the transmission of the user data packet, the control packet to the node group can be collectively transmitted by one output virtual connection.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. The virtual connection type network in this embodiment is ATM (Asynchronous Transfer Mode).
, Frame Relay, Fiber Channel, HIPPI (High Pe
rformance Parallel Interface).

The packet communication node refers to a packet switching device such as a router or a packet transmission / reception terminal. What is a node address? IP address, MAC address, IP
Refers to addresses such as X and AppleTalk.

The control packet is, for example, STII (St) which is exchanged between the transmitting and receiving terminals via the packet communication node.
ream Protocol II) and RSVP (Resource Reservation Prot
ocol) refers to packets for resource reservation protocols such as.

In this embodiment, when the packet communication node transmits a packet to the next-stage node using the virtual connection, the packet analysis / transfer means also includes both the destination node address field in the packet header and the protocol identifier. Then, the packet route table is referred to and the virtual connection to be transmitted is determined. That is, the packet route table is configured so that the output interface and the output virtual connection can be obtained by using both the destination node address field and the protocol identifier as search keys.

In the first embodiment of the present invention, even packets having the same destination node address (unicast or multicast) and transferred (transmitted) to the same next-stage node (next-stage node group in the case of multicast) are controlled. Two types of virtual connections for packets and user data packets are prepared, and control packets and user data packets are transferred (transmitted) using the respective virtual connections. In this way, the packet route table is also set.

In the embodiment of the second invention, among the packets having the same destination multicast address, the user data packet is transferred (transmitted) to the next stage node group which should receive / transfer the packet having the above multicast address. Transfer (send) using a virtual connection to do this. On the other hand, the control packet has a virtual connection for collectively transferring (transmitting) packets having not only the above multicast address but also other multicast addresses to the packet communication node group including the next-stage node group that should receive / transfer. Prepare and transfer (send) using it.

(Specific Example 1) FIG. 1 shows a configuration example of a packet communication node according to this example. The packet communication node 100 includes at least a packet receiving means 101, a packet analyzing / transferring means 102, a packet transmitting means 103, a TCP (Transmission C
ontrol Protocol), UDP (User Datagram Protocol), RSV
It is composed of an upper layer 104 such as P and a packet route table 105.

When the packet communication node 100 is a router,
When a packet is received from the packet receiving means 101, it is assembled from a data link layer frame (cell in the case of ATM) to a packet (IP datagram in the case of IP) and then sent to the packet analysis / transfer means 102. . The packet analysis / transfer means 102 searches the packet routing table 105 based on the header information of the received packet, determines the output interface and the output virtual connection to which the packet should be sent, and the packet transmission means corresponding to the determined output interface. Send to 103. The packet transmitting means 103 converts a packet into a data link layer frame (cell in the case of ATM), and transmits the data link layer frame toward the determined predetermined virtual connection.

A router will be described below as an example of the packet communication node. In FIG. 2, routers R1, R2, R3
Is connected to a virtual connection type network, and the other routers R and host H are connected to a connectionless type network such as Ethernet. FIG. 3 shows an example of a packet route table that is referred to when the packet having the destination address of the host abcd and the host efgh is transferred in the router R1.

As a key for searching the packet route table, the destination IP address and the protocol identifier in the packet header are used. The protocol identifier indicates whether the higher level protocol of the packet is TCP or UDP (indicating that it is a user data packet), or whether it is a control message such as RSVP (indicating that it is a control packet). There is. As a result of the search, the interface port that should output the packet, the IP address of the next-stage node, the identifier of the virtual connection that should be output (here, ATM connection VC (Vir
tual channel) identifier VPI / VCI is taken as an example).

When searching using only the destination IP address as a key as in the conventional packet routing table, a packet is sent to the same virtual connection regardless of whether the upper layer protocol is TCP or UDP or a control message such as RSVP. Will be output. In this example, as shown in FIG. 3, if the destination IP address is the same but the upper layer protocol is different, the packet is output to a different virtual connection. The IP address of the next-stage router of the packet whose destination IP address is abcd is pqrs, and as the VPI / VCI to the next-stage router, 100/200 for information (user data packet) transfer,
100/201 is used for RSVP control message (path message) (control packet) transfer.

Further, the IP address of the next router of the packet whose destination IP address is pqxy is pqrs, and 100/100 for information transfer as VPI / VCI to the next router,
100/201 is used for RSVP control message transfer. In this way, control packets having different destination IP addresses can be transferred using the same VC when the nodes in the next stage are the same.

A packet whose destination IP address is efgh is also transferred to the next-stage router pqrt using two different VCs. Each VC is set either by the ATM signaling procedure or the management procedure.

(Specific Example 2) A configuration example of the packet communication node according to this example is the same as that shown in FIG. In FIG. 4, routers R1, R2, R3 and R4 are connected to a virtual connection type network. Here, the case of multicast communication using an IP multicast address will be described. Multicast address 225.0.0.100 on router R1
FIG. 5 shows an example of a packet route table that is referred to when a packet having a multicast address 230.10.10.0 as a destination address is transferred.

The key for searching the packet route table uses the destination IP address (multicast group address) and the protocol identifier in the packet header. Search results,
The interface port that should output the packet, the virtual connection identifier that should be output (here, VPI / VCI of the ATM connection is taken as an example), etc. are obtained.

Routers R2 and R3 are assigned to the multicast address 225.0.0.100 and multicast address 230.10.10.0.
Shows the case where routers R3 and R4 are participating. In other words, there is a host subscribed to the multicast address 225.0.0.100 downstream of routers R2 and R3, and a multicast address 230.300 downstream of routers R3 and R4.
This means that there is a host subscribed to 10.10.0.

As shown in FIG. 5, when the destination IP multicast address is the same but the upper layer protocol is different, the packet is output to a different virtual connection. In this example, point to R2, R3 to send packets destined for multicast address 225.0.0.100-multipoint
One VC for information transfer (50/100) and one for RSVP control message transfer (50/200), multicast address 230.0.
To send a packet addressed to 0.100, use one point-multipoint VC addressed to R3 and R4 for information transfer (100/10) and RSVP control message transfer (100/11). Each point-AT for multipoint VC settings
It will be done by the signaling procedure of M or by the management procedure.

(Specific Example 3) A configuration example of the packet communication node according to this example is the same as that shown in FIG. Also, the method of using the virtual connection for information transfer is the same as in Example 2, but RS
As a virtual connection for transferring control messages such as VP, use the connection established for IP address 224.0.0.1 which means "to all local nodes participating in multicast communication". This state is shown in FIG.

In this example, a table as shown in FIG. 7 is used as the packet route table referred to by the router R1, and the key to be searched uses the destination IP address (multicast group address) and the protocol identifier in the packet header. Even if the destination IP multicast address is the same (225.0.0.100), if the upper protocol is TCP (user data packet), 50/100 VC is used, and if the upper protocol is RSVP (control packet), 50/333 VC is used. Use VC. And
Destination IP multicast address different from the above (230.10.1
However, if the upper protocol is RSVP (control packet of the same type as above), the same VC of 50/333 as above is used. Also, the destination IP multicast address is 224.0.0.1
Packet is also transferred with the same 50/333 VC. Note that the address 224.0.0.1 is, for example, IG
MP (Internet Group Management)
ent Protocol).

The VC of 50/333 is the above IP address
It is a point for R2, R3, and R4 that was set up for 224.0.0.1-a multipoint VC. ATM like this
Is performed in advance by the signaling procedure or the management procedure of.

In this example, since all the multicast participating nodes are members of this address 224.0.0.1, when a control message is sent to the point-multipoint VC destined for that address, a message not related to itself is sent. Downstream nodes will receive it, but such unrelated messages can be discarded on the receiving side.

Here, an example in which the control packet is sent to the connections that are addressed to all the local nodes participating in the multicast communication has been described, but some of a plurality of existing multicast groups are specified and this specification is performed. The control packet to a point-multipoint connection addressed to a local node (a node that has a host that subscribes to the multicast address downstream of it) that participates in any of the specified multicast groups. Can be realized by a similar mechanism.

(Specific Example 4) A configuration example of the packet communication node according to this example is the same as that shown in FIG. In this example, as shown in FIG. 8, a multicast server (MCS) for efficiently providing multicast communication of a plurality of senders is arranged.

The method of using the virtual connection for information transfer is the same as in the second and third embodiments, but the VC destined for the MCS is used as a virtual connection for the control message transfer such as RSVP, and the MCS that receives it uses the concrete example. 224.0. 0 mentioned in 3.
Point to 1-Transfer control messages to downstream nodes using multipoint VCs. In this case all sending nodes do not need to have point-multipoint VCs for control messages destined for 224.0.0.1, only point-point VCs destined for MCS.
Points for the number of senders-The number of VCs can be expected to be reduced compared to the case of having multipoint VCs.

FIG. 9 shows an example of the packet route table referred to by the router R1 in this example. Even though the destination IP multicast address is the same (225.0.0.100), the upper protocol is TCP
If it is (user data packet), 50/100 VC is used, and if the upper protocol is RSVP (control packet),
Use a VC of 25/888. And, even if the destination IP multicast address (230.10.10.0) different from the above, if the upper protocol is RSVP (control packet of the same type as above),
Use the same 25/888 VC as above. The same applies to packets with a destination IP multicast address of 224.0.0.1.
Transferred with a VC of / 888. This 25/888 VC is a point addressed to R2, R3, R4 that was set up for the above IP address 224.0.0.1.
-Point that can be switched by MCS to multipoint VC (10/555) -It is a point VC. Such settings are made in advance by the ATM signaling procedure or management procedure.

The MCS determines the interface and VPI / VCI to be output based on the VPI / VCI of the received cell. In this case, based on 25/888, point for control message addressed to 224.0.0.1-multipoint VC (10/555)
Has been decided. Point where control messages from multiple senders (received from different VCs) are the same-
It is desirable to assemble cells into ATM adaptation layer frames to avoid cell-level interleaving when sent to a multipoint VC.

Although the case where only the control packet is transferred using the MCS is shown as an example here, the user data packet itself may be transferred using the MCS. However, even in that case, different VCs for control message and information transfer are used.

[0043]

As described above, according to the present invention, by using information other than the destination address in determining the output virtual connection of a packet, the virtual connection used for transmitting the user data packet and the control packet can be transmitted. It is possible to separate the virtual connections used.

As a result, when the input virtual connection and the output virtual connection are applied to the router which is directly connected inside the router, the virtual connection used for transmitting the user data packet is directly connected and used for transmitting the control message packet. The virtual connection performs the processing of the network layer so that the control message can be recognized by the router.

Alternatively, the control packet can be transferred even when an abnormality occurs in the virtual connection that is transferring the user data packet. Further, according to the present invention, it is possible to simultaneously control the plurality of related virtual connections with one message.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a packet communication node of this embodiment.

FIG. 2 is a diagram showing a method of using a virtual connection in Specific Example 1.

FIG. 3 is a diagram showing an example of a packet route table in Specific Example 1.

FIG. 4 is a diagram showing a method of using a virtual connection in a specific example 2.

FIG. 5 is a diagram showing an example of a packet route table in Specific Example 2.

FIG. 6 is a diagram showing a method of using a virtual connection in a specific example 3;

FIG. 7 is a diagram showing an example of a packet route table in Specific Example 3.

FIG. 8 is a diagram showing a method of using a virtual connection in a specific example 4.

FIG. 9 is a diagram showing an example of a packet route table in Specific Example 4.

[Explanation of symbols]

100 ... Packet communication node 101 ... Packet receiving means 102 ... Packet analysis / transfer means 103 ... Packet transmitting means 104 ... Upper layer 105 ... Packet route table

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04L 12/56 100

Claims (6)

(57) [Claims] 1. A control information transfer method when a packet communication node connected to a virtual connection type network and transmitting and receiving user data and various control packets transmits a packet group to a next stage node. An output virtual connection for sending and an output virtual connection for sending a control packet identified by an identifier in the packet are set respectively, and the output node of the destination node address field included in the packet to be sent is set. The control packet having a predetermined destination node address is controlled to be transmitted by an output virtual connection different from the output virtual connection transmitting the user data packet having the same destination node address based on the information and the protocol identification information. Control information transfer method. 2. A packet communication node, which is connected to a virtual connection type network and transmits / receives user data and various control packets, sends a packet group whose destination node address is a multicast address to a next-stage node group corresponding to the multicast group. In the control information transfer method when transmitting, a plurality of output virtual connections for transmitting a user data packet to each of the next-stage node groups corresponding to a plurality of multicast groups and an identifier in the packet are used.
A destination multicast address included in the multicast packet to be transmitted, which is set with one output virtual connection for collectively transmitting the control packets identified by the above to the next-stage node group corresponding to the plurality of multicast groups. Based on the information of the field and the protocol identification information, the control packet having the predetermined destination multicast address is transmitted by the one output virtual connection different from the output virtual connection transmitting the user data packet having the same destination multicast address. A control information transfer method characterized by controlling. 3. Identified by an identifier in the packet
The control packet used is a resource reservation protocol.
Control information according to claim 1 or 2, characterized in that
Transfer method. 4. A packet transmitting means for transmitting user data and various control packets by connecting to a virtual connection type network, a user data packet having the same destination node address, and a control packet identified by an identifier in the packet. Storage means in which the correspondence relationship is stored so that they can be transmitted by different output virtual connections, and the storage means is referred to based on the information of the destination node address field and the protocol identification information included in the packet to be transmitted, A packet for transferring a packet while determining an output interface to the node and an output virtual connection to the next-stage node and instructing the packet transmitting means of the determined output interface to transmit the packet through the determined output virtual connection. Equipped with analysis and transfer means Node device according to claim. 5. A packet transmitting means for connecting to a virtual connection type network and transmitting user data and various control packets, and a user data packet whose destination node address is a multicast address, a next stage node group corresponding to the multicast group. Different from the output virtual connection for sending to, it is an output virtual connection that can collectively send packets to the next stage node group corresponding to multiple multicast groups, and is identified by the identifier in the packet
Storage means storing the correspondence so that the control packet can be transmitted, and referring to the storage means based on the information of the destination multicast address field and the protocol identification information included in the packet to be transmitted, to the next node Output interface and output virtual connection to the next-stage node are determined, and the packet analysis unit transfers the packet while instructing the packet transmitting means of the determined output interface to transmit the packet through the determined output virtual connection. A node device comprising: a transfer unit. 6. Identified by an identifier in the packet
The control packet used is a resource reservation protocol.
The node device according to claim 4 or 5, characterized in that
Place