KR101200407B1 - Method for multicasting and access gateway - Google Patents

Abstract

A multicast method is disclosed. The multicast method according to the present invention includes detecting a link from a mobile node to a first mobile access gateway (MAG) and updating a cache of information of the mobile node in a first multicast handover agent (MHA) in the first MAG. Linking the first MHA with the second MHA in the second MAG and sending the mobile node's information to the second MHA so that the second MAG forms a link with the mobile node.

Description

Multicast method and access gateway

The present invention relates to a multicast method, and more particularly, to a multicast method and an access gateway for implementing fast handover in multicast.

Multicast relates to a method for transmitting packets of the same content from one transmitting node to a plurality of receiving nodes. Broadcast differs from broadcast in that multicast is transmitting data to a specific number of targets, compared to sending data from a transmitting node to an unspecified number of targets.

In addition, unicast is different from unicast in that a transmitting node and a receiving node are matched 1: 1 and transmit data.

In the case of the broadcast method, since data is transmitted to a user who does not want to receive specific data, a problem arises in that a waste of resources is caused. In addition, unicast also causes a waste of resources in that the number of users who need to receive a specific data increases to establish a transmitting node. In this context, the use of multicast has recently increased, and research on multicast has been actively conducted.

1 is a conceptual diagram illustrating a general multicast method.

As shown in Figure 1, the multicast method is organized into a multitask core tree. The multitask core tree includes a local mobility anchor (LMA) 100-1, 100-2, first and second mobile access gateways 210, 220, and a plurality of mobile nodes 300.

The LMA 100-1 may be linked to the first MAG or the second MAG 210, 220. The first MAG may form a link with the plurality of mobile nodes 300, and the first MAG 210 may transmit data to the mobile node 300 in which the link is formed in a certain physical area.

In order for the mobile node 300 to receive data from the first or second MAGs 210 and 220, the mobile node 300 must join a multicast group of the first or second MAG. Here, the multicast group may mean an IP address corresponding to class D (224.0.0.0 to 239.255.255.255).

However, when the mobile node 300 moves from the area of the first MAG 210 to the area of the second MAG 220, in order to receive data from the second MAG 220, the second MAG ( Join a multicast group of 220).

However, in order to join a multicast group, a certain subscription procedure is required, and thus a problem occurs that data cannot be received for the time required for subscription.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a multicast method and an access gateway for implementing a fast handover.

In a multicast method according to an embodiment of the present invention for detecting the above-mentioned problem, detecting a link from a mobile node to a first mobile access gateway (MAG), and a first multicast handover agent (MHA) in the first MAG. Updating the cache for the information of the mobile node, linking the first MHA with a second MHA in a second MAG, and transmitting information of the mobile node to the second MHA so that the second MAG receives the information. And forming a link with the mobile node.

Wherein updating the cache for information of the mobile node in the first MHA comprises: (a) the mobile node sending a proxy message to the first MHA and (b) the proxy message based on the proxy message; Updating the cache for information of the mobile node.

And linking the first MHA with a second MHA in the second MAG includes: (c) the first MHA sending a context transfer request to the second MHA; and (d) the second MHA is And sending an ack for the context transfer request to a first MHA.

In addition, the context transfer request may include at least one of an ID of the mobile node, a network prefix assigned to the mobile node, and an IP address of the mobile node.

Meanwhile, the multicast method may further include updating the second MAG by PMIP binding before forming the link between the second MAG and the mobile node.

In this case, the PMIP binding update may include at least one of an ID of the mobile node, a network prefix assigned to the mobile node, and an IP address of the mobile node.

The multicast method may further include transmitting a link establishment notification message from the second MHA to the first MHA after establishing a link between the second MAG and the mobile node.

In addition, the multicast method may further include the step of releasing the link between the first MAG and the mobile node when the first MHA receives the link establishment notification message.

In addition, the step of the second MAG to form a link with the mobile node, updating the cache for the information of the mobile node in the second MHA, by using the information of the mobile node and the second MAG and the mobile; It can also form links with nodes.

On the other hand, the access gateway according to another embodiment of the present invention is a sensing unit for detecting a link from the mobile node, an interface unit for transmitting the multi-task data to the mobile node, receiving the information of the mobile node from the mobile node and the It may include a multihand handover agent (MHA) unit to update the cache for the information of the mobile node, to form a link with the external MAG.

The information of the mobile node may include at least one of an ID of the mobile node, a network prefix assigned to the mobile node, and an IP address of the mobile node.

According to various embodiments of the present disclosure, when a mobile node moves from an area of a specific MAG to another area of the MAG, it is possible to reduce the time required for the subscription, and thus cannot receive data for a predetermined time. The problem can be solved. As a result, seamless multicast data transmission can be implemented.

1 is a conceptual diagram illustrating a conventional general multicast method.
2 is a block diagram illustrating a multicast core tree according to an embodiment of the present invention.
3 is a timing diagram illustrating the operation of a multicast tree structure according to an embodiment of the present invention.
4 is a flowchart illustrating a multicast method according to another embodiment of the present invention.

Hereinafter, various embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings.

In the context of the present invention, a multitasking method implemented by PMIPv6 will be described.

Since PMIPv6 is a mobility management technology for unicast service, the basic standard does not provide a method for supporting multicasting. In order to provide multicasting service, IGMP / MLD's membership management protocol for client's channel request question / response is provided. There is a history developed as multicast routing is required at the gateway router location for the participation participation of the multicast stream for the channel requested by the client and the client.

However, when performing the function in the PMIPv6 server, various factors such as the modification of the existing PMIPv6, the overhead of channel subscription / unsubscription due to the frequent movement of mobile nodes, and resource management in the network should be considered. Therefore, the ongoing PMIPv6 multicasting solution aims to standardize in consideration of these requirements.

In the PMIPv6 network, multicasting is supported by the upstream interface of the LMA and the IGMP / MLD protocol for the membership management with the host. The Mobile Access Gateway (MAG) handles the functionality of the IGMP / MLD Forwarding Proxy (IGMP / MLD Forwarding Proxy), as defined in RFC 4605. The Mobile Access Gateway (MAG) provides the role of forwarding of membership query / response messages between the mobile mobile node and the LMA. It automatically checks whether a node is received.

Hereinafter, various embodiments of the present invention, which are particularly applied in the PMIPv6 environment, will be described.

2 is a block diagram illustrating a multicast core tree according to an embodiment of the present invention.

As shown in FIG. 2, the multicast core tree includes LMAs 100-1, 100-2, first and second MAGs 210 and 220, first and second multicast handover agents 211 and 212, and a plurality of mobile nodes. (mobile node, 300).

The LMA 100-1, 100-2 may operate as a kind of home agent for a mobile node in an access network. That is, the LMA 100-1 and 100-2 may be a router connected to a home network capable of transmitting a packet to the mobile node 300 or receiving a packet from the mobile node 300.

The first and second MAGs 210 and 220 may be devices that support mobility of the mobile node on behalf of the mobile node. Although not shown, each MAG may include a detector for detecting a link from the mobile node 300. In addition, each MAG may include an interface unit for transmitting multicast data to the mobile node or receiving information of the mobile node 300. In addition, the mobile node 300 may include an MHA unit, the MHA unit may store information of the mobile node 300, and may also transmit or receive information of the mobile node 300 to another MHA. That is, a link with an external MAG can be formed. In addition, when there is a link formation request from the mobile node 300, the MHA unit excludes a predetermined subscription procedure by using the information of the mobile node 300, and permits the mobile node 300 to transmit. 300) Management can be performed.

When the mobile node 300 enters the PMIPv6 network, the first and second MAGs 210 and 220 connect the LMA 100-100 to which the mobile node 300 attempts to access from a policy store (not shown) in the access network. Information such as an address of 1 or 100-2), ID information of the mobile node 300, and a network prefix that may be additionally assigned to the mobile node.

Using the information received from a server (not shown), the MAGs 210 and 220 may transmit an RA message to the mobile node 300, and the mobile node 300 may set an IP address of the mobile node 300 using the message. have.

The MAGs 210 and 220 also use the received information to create a Proxy Binding Update (PBU) message and send it to the LMA. This message includes the ID of the mobile node 300, the network prefix assigned to the mobile node 300, and the IP address of the mobile node 300.

Upon receiving the PBU message, the LMA 100-1 or 100-2 checks whether there is information corresponding to the ID of the mobile node 300 in its Binding Cache entry, and adds information on the mobile node 300 if it is not present. do.

Thereafter, the LMA 100-1 or 100-2 may establish a tunnel between the LMA and the MAG by using address information of the MAGs 210 and 220.

When the mobile node 300 moves, i.e., when the mobile node 300 moves from the first MAG area 210 to the area of the second MAG 220, the second MAG as described above. 220 typically obtains information about the mobile node 300 and can use this information to send the same network prefix information to the mobile node 300.

If the mobile node receives the same network prefix information, the mobile node may assume that it is still connected to the same network as before, so that the new MAG, ie the second MAG 220, receives the mobile node 300 from the server. ) To create a PBU message and send it to the LMA 100-1 or 100-2.

The LMA 100-1 or 100-2 receiving the PBU message uses the ID information of the mobile node 300 and the address information of the second MAG 220, so that the mobile node 300 has a new network, that is, the second MAG. Detects that the mobile station 300 has moved to the area (220) and establishes a tunnel between the LMA 100-1 or 100-2 and the first MAG 210 for the mobile node 300 with the LMA 100-1 or 100-2. It can be changed to the tunnel between the second MAG (220).

In the above-described method, the network-based mobility management function may be provided to the mobile node 300.

However, as pointed out in the problem of the prior art, when the mobile node 300 moves from the first MAG region 220 to the second MAG region 210, as described above, the second MAG 220 is mobile. A predetermined time is required to receive the above-described information from the node 300, and this problem can be solved using the first and second mobile handover agents (211,221).

The first and second mobile handover agents 211 and 221 may be disposed in the first and second MAGs 210 and 220, respectively.

In the case where the mobile node 300 moves into the area of the first MAG 210, the first MAG 210 may update the mobile node 300 information as described above. More specifically, the first MHA 211 uses a cache to hold a list for a plurality of mobile nodes (not shown) and can also maintain the cache.

Immediately after the first MAG 210 updates the mobile node 300 information, the first MHA 211 may transmit the mobile node 300 information to the second MHA 212. The first MHA 211 may also transmit information directly, including information transmitting means for transmitting mobile node 300 information directly to the second MHA 212, as shown in FIG. Information may be transmitted to the second MHA 212 via 100-1 or 100-2.

When the mobile node 300 moves from the first MAG 210 area to the second MAG 220 area, the mobile node 300 information is transmitted to the second MHA disposed inside the second MAG 220. Therefore, a procedure such as requesting and approving the mobile node 300 to the second MAG 220 may be excluded, thereby reducing the time required.

Here, the mobile node 300 may determine to move from the first MAG 210 area to the second MAG 220 area, so that the mobile node 300 may request a link to the second MAG. have.

The determination that the mobile node 300 moves from the first MAG 210 region to the second MAG 220 region indicates that the mobile node 300 has a signal strength from the first MAG 210 with the second MAG 220. It may be implemented by determining that the signal strength from the smaller than, since such a configuration is obvious to those skilled in the art, more detailed description will be omitted.

However, as described above, when the mobile node 300 moves, the second MAG may adopt a method of directly receiving a message from the mobile mobile node 300, and also, as described above, the first and second Information of the mobile node 300 may be obtained using the MHAs 211 and 221.

Hereinafter, a multicast method according to an embodiment of the present invention will be described with reference to FIG. 3.

3 is a timing diagram illustrating the operation of a multicast tree structure according to an embodiment of the present invention.

As shown in FIG. 3, the LMA 100-1 transmits multicast data to the mobile node 300 using the first MAG 210.

When a link formation from the mobile node 300 to the first MAG 210 is detected, the mobile node 300 may transmit a proxy MLD report to the first MAG 210.

The first MHA 211 disposed inside the first MAG 210 may update a cache regarding information about the mobile node 300 based on the proxy message.

Immediately after the first MHA 211 updates the cache for the mobile node 300 information, the first MHA 211 transmits the mobile node 300 information to the second MHA 221 disposed in the second MAG 220. It may transmit a context transfer request (CTR) including a.

After transmitting the context transfer request from the first MHA 211, the second MHA 221 may update the cache for the mobile node 300 information included in the context transfer request.

After updating the cache for the mobile node 300 information, the second MHA 221 may transmit a multicast listner discovery (MLD) report to the LMA 100-1. Also, the second MHA 221 may transmit an ack (CTA) indicating that the mobile node 300 has been successfully received to the first MHA 211.

Then, when the mobile node 300 moves from the first MAG 210 area to the second MAG 220 area, the second MAG 220 updates the mobile node 300 information in the second MHA 221. May be provided to the second MAG 220.

The second MAG 220 may form a link between the second MAG 220 and the mobile node 300 without a predetermined subscription procedure based on the mobile node 300 information provided from the second MHA 221. .

When the link between the second MAG 220 and the mobile node 300 is formed, the second MAG 220 may generate a PBU (Proxy Binding Update) message for the link formation and transmit it to the LMA. The PBU message may include the ID of the mobile node 300, the assigned network prefix, and the IP address of the mobile node 300.

The LMA 100-1 may send an ack (PBA) to the second MAG 220 to notify that it has successfully received the PBU message.

Thereafter, the LMA 100-1 may provide the multicast data to the mobile node 300 using a link formed between the second MAG 220 and the mobile node 300.

According to the embodiment described above, when the mobile node 300 moves from the first MAG 210 area to the second MAG 220 area, seamless multicast data transmission is performed without taking a predetermined time according to the subscription procedure. Can be implemented.

4 is a flowchart illustrating a multicast method according to another embodiment of the present invention. However, in order to avoid duplication of description, the description of the above-described parts with respect to the multicast structure will be omitted.

As shown in FIG. 4, the first MAG 210 may detect a link between the mobile node 300 and the first MAG 210 (S610).

After detecting the link of the mobile node 300, the first MAG 210 may update the information of the mobile node 300 to the first MHA 211 (S620). Herein, the mobile node 300 information may include at least one of an ID, a network prefix assigned to the mobile node 300, and an IP address of the mobile node 300.

Immediately after the first MHA 211 updates the mobile node 300 information, the first MHA 211 may form a link with the second MHA 212 (S630).

The second MHA 212 may receive and update the mobile node 300 information from the first MHA by using a link formed between the first MHA 211 and the second MHA 212 (S640).

Subsequently, when the mobile node 300 moves from the area of the first MGA 210 to the area of the second MGA 220, the second MHA 221 connects the mobile node 300 to the second MAG 220. Information may be provided, and the second MAG 220 may exclude the mobile node 300 joining procedure and form a link between the second MAG 220 and the mobile node 300 (S650).

Meanwhile, the second MHA 221 may establish a link with the mobile node 300, and then transmit a message indicating a link formation with the mobile node 300, that is, a link formation notification message, to the first MHA 211.

The first MAG 210 may release the link if the link between the first MAG 210 and the mobile node 210 is established using the message provided from the first MHA 211.

According to the embodiment described above, when the mobile node 300 moves from the first MAG 210 area to the second MAG 220 area, seamless multicast data transmission is performed without taking a predetermined time according to the subscription procedure. Can be implemented.

In addition, multicast group join of the mobile node can be performed quickly, thereby preventing data loss for multicast data that cannot be received until the multicast group join is completed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It goes without saying that the example can be variously changed. Therefore, various modifications may be made without departing from the spirit of the invention as claimed in the claims, and such modifications should not be individually understood from the technical spirit or outlook of the invention.

100-1, 100-2: LMA 210: First MAG
220: second MAG 211: first MHA
212: Second MHA 300: Mobile Node

Claims (11)

Detecting a link from a mobile node to a first mobile access gateway (MAG);
Updating a cache for information of the mobile node with a first multicast handover agent (MHA) in the first MAG;
Linking the first MHA with a second MHA in a second MAG; And
Transmitting the information of the mobile node to the second MHA so that the second MAG forms a link with the mobile node. The method of claim 1,
Updating the cache for information of the mobile node in the first MHA,
(a) the mobile node sending a proxy message to the first MHA; And
(b) updating the cache for the information of the mobile node based on the proxy message. The method of claim 1,
Linking the first MHA with a second MHA in the second MAG,
(c) the first MHA sending a context transfer request to the second MHA; And
(d) the second MHA sending an ack for the context transfer request to the first MHA. The method of claim 3, wherein
Wherein the context transfer request includes at least one of an ID of the mobile node, a network prefix assigned to the mobile node, and an IP address of the mobile node. The method of claim 1,
Prior to the step of forming a link between the second MAG and the mobile node,
And PMIP binding updating the second MAG. The method of claim 5, wherein
The PMIP binding update comprises at least one of an ID of the mobile node, a network prefix assigned to the mobile node, and an IP address of the mobile node. The method of claim 1,
After forming a link between the second MAG and the mobile node,
Sending a link establishment notification message from the second MHA to the first MHA. The method of claim 7, wherein
If the first MHA receives a link establishment notification message, releasing the link between the first MAG and the mobile node. The method of claim 1,
Causing the second MAG to form a link with the mobile node,
And updating the cache of the information of the mobile node in the second MHA to form a link between the second MAG and the mobile node using the information of the mobile node. A detector for detecting a link from the mobile node;
An interface unit which transmits multicast data to the mobile node and receives information of the mobile node from the mobile node; And
A multihand handover agent (MHA) that updates a cache for information of the mobile node, sends a context transfer request to an external MAG, receives an ack for the context transfer request from the external MAG, and forms a link with the external MAG. An access gateway comprising a part. The method of claim 10,
And wherein the information of the mobile node comprises at least one of an ID of the mobile node, a network prefix assigned to the mobile node, and an IP address of the mobile node.

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