JPH0964915A - Packet transmission node equipment and packet transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a service quality different from each recipient with respect to a multi-cast address. SOLUTION: Plural output virtual connections (point-to-multi-point connection or point-to-point connection to a multi-cast server) taking a transmission node to be a start point are used to realize a multi-cast communication of entirely one multi-cast server, and different service classes are included in the plural output virtual connections and an inputted packet is sent to any of the plural output virtual connections.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet transmission node device such as a router or a host, which is connected to a virtual connection type network and transmits / receives a packet, and a packet transfer method.

[0002]

2. Description of the Related Art What is a virtual connection type network?
ATM (Asynchronous Transfer Mode), frame relay,
Fiber Channel, HIPPI (High Performance Parallel
Interface) refers to networks based on such technologies.

Multicast performed on such a network means that when a sender sends one packet to a multicast destination address in the network layer,
A network distributes packets to multiple recipients. In the following, for simplification of explanation, an IP (Internet Protocol) is taken as an example in the network layer, and an ATM is used.
(Asynchronous Transfer Mode) IP multicast communication on the network will be described.

FIG. 5 shows the transfer of a packet addressed to the multicast address G. H0-9 is the host,
H0 is the sender of the packet. The recipients of the packet are the hosts H1, H2, H4, H5, H6, H7, H8. R is a router that forwards packets. Assume that the host and router are connected by ATM.

When the network layer is IP, nodes (hosts and routers) belong to a logical group of IP subnets. The communication within the same IP subnet can be directly transferred without passing through the router, and the communication between different IP subnets is transferred by the router. In FIG.
H0, H8, R belong to IP subnet A, H1, H2, H3, R belong to IP subnet B, H4, H5, H6, H7 belong to IP subnet C, and H9, R belong to
Belong to IP subnet D.

Direct transfer within the same subnet uses a point-multipoint connection of ATM or a multicast server (M
It can be realized by using (CS).

Now, with such a configuration, the transfer method when a packet is sent from H0 to the multicast address G is as follows. First, H0 transfers a packet addressed to G to H8 and R using ATM point multipoint. Since H8 is a host, it receives packets and processes them. Since R is a router, it will send packets to other subnets (subnets) that have joined multicast address G.
Transfer to B, C). For subnet B, packet (MC
S), and the MCS sends the packet to H1 and H2 on the point-multipoint connection. On the other hand, subnet C has H4, H5, H
Send to 6, H7. Subnet D does not forward because there are no hosts participating in multicast address G.

[0008]

As described above, conventionally, one point-multipoint connection is used for a destination address for one multicast address, or a point-point connection to a multicast server is used. Therefore, only one multicast address can provide the same quality of service.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and in a packet transmission node device connected to at least one virtual connection type network, a service is provided to a multicast destination address. Storage means for storing at least identifiers of a plurality of output virtual connections including virtual connections having different qualities, based on the destination address of the input packet, referring to the storage means, determining the output virtual connection of the packet, Means for transferring the packet to the determined output virtual connection.

Here, the storage means stores the identifiers of a plurality of output virtual connections including virtual connections having different service qualities with respect to the set of the source address and the multicast destination address. The storage means may be referred to based on the transmission source address and the destination address.

Further, according to the present invention, when a packet communication node connecting to a virtual connection type network and transmitting / receiving a packet transmits a packet whose destination address is a multicast address to a group of nodes corresponding to the multicast group. In the packet transfer method, the output virtual connections for transmitting packets to the respective subnode groups are respectively set so that the nodes corresponding to one multicast group are composed of a plurality of subnode groups and virtual connections with different quality of service exist. It is characterized in that it is set and controlled so that the multicast packet is transmitted to each of the corresponding plurality of output virtual connections based on the information of the destination address field included in the multicast packet to be transmitted.

According to the present invention, a plurality of output virtual connections starting from the transmitting node realizes the multicast communication of one multicast group as a whole, and the plurality of output virtual connections are at least one. Point-to-multipoint connection, or point-to-point connection to a multicast server (this is connected to a point-to-multipoint connection from the multicast server to some of the nodes that correspond to the multicast group)
And other connections. Other connections may be point-to-point, point-to-multipoint, or point-to-point to the multicast server.

The plurality of output virtual connections are set so that at least one of them has a quality of service different from that of other connections, and one input packet is , Will be sent to any of these multiple output virtual connections. Therefore, different quality of service can be provided to one multicast address.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. In this embodiment, the node device connected to at least one virtual connection network,
Based on the source and destination addresses of the packet and the output interface of the transfer destination, the output virtual connection identifier, the storage means for storing at least the quality of service, and the destination address of the input packet, or the combination of the source and the destination address, While referring to the storage means, determining the output interface and the output virtual connection to be the destination of the packet, and directing the packet transmitting means of the determined output interface to transmit the packet with the determined output virtual connection , Transfer means for transferring packets.

The storage means stores a plurality of output virtual connection identifiers for one multicast destination address or one source and destination address set, and for one multicast address. Since multiple point-multipoint connections are used, it is possible to provide different quality of service for each output virtual connection, and thus for each receiver.
The mechanism of the present embodiment can also be used in combination with the conventional multicast distribution mechanism, and if all the host groups participating in one multicast address require the same quality of service, the conventional mechanism is used. Using the mechanism of
The mechanism of this embodiment can be used when there are hosts that require different service qualities.

(Specific Example) In this example, a method of transferring a multicast packet at a node (host / router) will be described. First, an overall packet flow will be shown, and then the node configuration and packet transmission procedure will be described.

The overall packet flow will be described with reference to FIG. This figure shows multicast address G
It shows the transfer of packets addressed to it. H0-9 is the host and H0 is the sender of the packet. The recipients of the packet are H1, H2, H4, H5, H6, H7, H8 corresponding to G. R is a router that forwards packets. # 1, # 2 around the router,
# 3 shows the output I / F number of the router. Host and router
It is assumed that they are connected by ATM.

When the network layer is IP, a node
It belongs to an IP subnet, which is a logical group. The communication within the same IP subnet can be directly transferred without passing through the router, and the communication between different IP subnets is transferred by the router. In Figure 1, H0, H8, R belong to IP subnet A, H1, H2, H3, R belong to IP subnet B, H4, H5,
H6 and H7 belong to IP subnet C, and H9 and R belong to IP subnet D.

The difference from the conventional method is that the packet transfer from the router R to the host (H4-H7) is VPI / VCI = 10/100 and VP.
It is to transfer to two ATM connections with I / VCI = 10/101.

As described above, in order for the router to copy a packet with the same destination to two ATM connections and transfer it,
The packet transmission procedure in the router is as follows. In the above, only the router is shown, but the same can be said for the host that sends the packet, so in the following, both the router and the host are collectively referred to as a node,
The packet transmission procedure at the node will be described.

First, the configuration of the node will be described with reference to FIG. The solid line in the figure shows the flow of packets, and the broken line shows the flow of control information for reference in the table. Packet receiver (1
01) is connected to a LAN (Local Area Network) such as ATM. It also has the role of assembling a data link layer frame received from a LAN into a network layer packet from the data link layer frame according to the LAN protocol. Here, ATM is used as the data link layer frame.
It is a cell and becomes an IP packet as a network layer packet.

The packet analysis transfer unit (102) judges whether the packet is addressed to itself and, if the packet is addressed to itself, passes the packet to the upper layer (104). If the packet is not addressed to itself, the network layer is processed, the packet is referred to, and the output interface and the next-stage node or the output connection identifier is determined according to the route table (105). The output connection is VC (Virtual) for ATM.
Channel) and its identifier is VPI / VCI. The output packet passed from the upper layer (104) is similarly processed in the network layer, and the output interface and the next node or the output connection identifier is determined according to the route table (105).

The packet transmission unit (103) converts the packet delivered from the packet analysis transfer unit (102) into a data link layer frame of the connected LAN and delivers it from the packet analysis transfer unit (102). The data link layer frame is sent to LA according to the identifier of the next-stage node or output connection.
Send to N.

The upper layer (104) is a TCP (Transmission Contr
ol Protocol) and UDP (User Datagram Protocol). Specifically, this corresponds to a route protocol or application software for exchanging route information.

The route table (105) includes a packet analysis transfer unit (10
Referenced by 2). This table is either statically set or dynamically set by the routing protocol. The route table (105) in the case of FIG. 1 is as shown in FIG. The routing table at the node can search the output I / F, output VPI / VCI, and quality of service by using the source (source) and destination address of the packet to be transferred as keys. When the importance is written in the packet by a method such as hierarchical coding described later, and when deciding which packet to transmit by the importance,
Multicast packets are transferred / transmitted by referring to the service quality.However, when the importance is not written in the packet or all packets are sent, the service is not used when actually transferring / transmitting the multicast packet. -No need to refer to screw quality. The search key may be a destination address only without using the source.

In this example, since one packet may be sent to a plurality of interfaces and output connections, the output I / F and the output VPI / VCI of the routing table (105) may be transmitted.
Are required for one destination address or a combination of source and destination addresses. Therefore, a routing table (105) is created by a linked list that connects a plurality of output routes using a pointer.

Here, the source is H0 and the destination address is G.
Output I / F is # 3, output VP
ATM connection (A) with I / VCI is 10/100 and quality of service is 1, output I / F is # 3, output VPI / VCI is 10/101,
ATM connection (B) with quality of service 2 and output I / F # 2, output VPI / VCI 10/105, quality of service 1
The routing table is set so that the packet is transferred to and from the ATM connection (C).

Of the node groups H1, H2, H4, H5, H6, H7 corresponding to the multicast group G, the ATM connection (A) is the point where the host H4, H5 (corresponding to the sub node group) terminates. The ATM connection (B) is a multipoint connection, and the ATM connection (B) is a point-multipoint connection that terminates at hosts H6 and H7 (corresponding to the subnode group). The ATM connection (C) is a point-point connection to the multicast server. (It is connected to the point-multipoint connection from the multicast server to the hosts H1, H2 (corresponding to the subnode group)).

Various modifications can be made such that the ATM connection (A) is a point-point connection to the hosts H4 and H5 and a point-point connection to a multicast server for connection to the multipoint connection.

The ATM connection and the routing table are set in such a manner that the quality of service required by the receiving side (for example, H4, H5, H6, H7) (for example, the bandwidth requested by H4, H5 is H
ATM connection (VC with quality of service 1 terminating at H4, H5 and VC with quality of service 2 terminating at H6, H7) that satisfies this requirement based on (more than the bandwidth requested by H6, H7) This is done by registering information about these connections in the routing table.

Next, the transfer procedure will be described with reference to FIG. Router receives multicast packets as packet receiver
This procedure is performed when the packet is received at (101) and the packet is transferred to the next-stage node, or when the host sends the packet from the upper layer (104).

The packet coming to the packet analysis / transfer section (102) is analyzed, and the route table (105) is searched by the source and destination addresses of the packet. As for the search, a method of searching only by the destination address can be considered. While the output route is written in the routing table, it is referred to and the packet is sent to the output VPI / VCI of the written output I / F according to the quality of service specified for the connection.
The packet transmission according to the quality of service is to thin out packets. For example, by using a hierarchical coding method or the like, the importance of the packet is noted in each packet, and the packet to be transmitted is based on this importance and the service quality specified for the connection. Select. This is repeated many times, and when the process of sending one packet to all the output connections written in the routing table is completed, the process ends. In this way,
One packet with the same destination can be duplicated and transferred to multiple ATM connections.

Taking FIG. 1 as an example, in router R, source H0,
When it receives a packet to destination G, it searches the routing table and
Transfer the packet to output I / F = # 3, VPI / VCI = 10/100, quality of service = 1. Next, search the routing table and output I / F = # 3, VPI
It turns out that / VCI = 10/101 and quality of service = 2, and transfers the packet here. Finally, I / F = # 2, VPI / VCI = 10 /
The packet is transferred to 105, quality of service = 1, and the transfer ends.

[0034]

Since a plurality of output virtual connections including a point-multipoint connection can be used for one multicast address, different quality of service can be provided for each receiver.

[Brief description of drawings]

FIG. 1 is a multicast address G to which the present invention is applied.
FIG. 6 is a diagram showing an example of a state of multicast transfer of the packet of FIG.

FIG. 2 is a diagram showing a configuration example of a node according to the present embodiment.

FIG. 3 is a diagram showing an example of a route table.

FIG. 4 is a diagram showing a packet transfer procedure of a node.

FIG. 5 is a diagram showing how multicast packets of a multicast address G are transferred.

[Explanation of symbols]

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

Claims (3)

[Claims] 1. A packet transmission node device connected to at least one virtual connection type network, and storage means for storing at least identifiers of a plurality of output virtual connections including virtual connections having different service qualities with respect to a multicast destination address. And, based on the destination address of the inputted packet, referring to the storage means, determining an output virtual connection of the packet, and transferring the packet to the determined output virtual connection. And a packet transmitting node device. 2. The storage means stores identifiers of a plurality of output virtual connections including virtual connections having different service qualities with respect to a set of a source address and a multicast destination address. The packet transmitting node device according to claim 1, wherein the storage means is referred to based on a source address and a destination address. 3. A packet transfer method when a packet communication node, which is connected to a virtual connection type network and transmits / receives packets, transmits a packet whose destination address is a multicast address to a group of nodes corresponding to the multicast group. , The output virtual connection for sending packets to each subnode group is set so that the node group corresponding to one multicast group consists of multiple subnode groups and there are virtual connections with different quality of service. A packet transfer method characterized in that the multicast packet is controlled to be transmitted to each of the plurality of corresponding output virtual connections based on information of a destination address field included in the multicast packet to be transmitted.