KR20030038440A - Multicast Transfer System for xDSL Network - Google Patents

Abstract

PURPOSE: A multicast transmission system for an xDSL network is provided to transmit multicast data to a vast amount of users by efficiently processing network traffic. CONSTITUTION: A multicast transmission system for an xDSL network includes a virtual multicast router, a multicast agent, and a multicast management server. The virtual multicast router has a multicast transmission tree function for transmitting multicast data and a multicast data transmission/reception function. The multicast agent receives multicast data sent from the virtual multicast router to transmit the multicast data to an application program of a user. The multicast management server manages information required for finding the virtual multicast router closest to the user.

Description

Multicast Transfer System for XDSL Network

The present invention relates to a method and system for providing a multicast service without replacing an existing router or switch in an xDSL network.

Just as regular broadcasts are broadcast over radio or cable TV networks, data streams can be broadcast over the Internet. In other words, as a general broadcast can send a broadcast to all the receivers who want to receive the radio with only one radio transmission, the multicast technology allows the sender to selectively send all data to a desired receiver by sending only one data stream. Technology. In order to use the multicast technology, the network must be converted to a multicast network using a multicast device in which the multicast technology is implemented.

In a multicast network, broadcast capacity can be broadcast regardless of the number of users. In other words, since the capacity of the cable TV network is 30Mbps, it is possible to send 30 1Mbps broadcasts to 60 at the same time for 500kbps broadcasts.

Although multicast is so useful, there are a number of limitations to the transition of the existing Internet to multicast networks. This is because the equipment often does not support the multicast function or does not perform properly, and the cost of replacing the equipment that does not support multicast is too high.

Until now, in order to support multicast in the Internet network, all routers had to operate the multicast function between the information source and the end terminal. If the intermediate network does not support multicast, tunneling can be used. In other words, this method also skips the router when the intermediate router does not support multicast. This method requires manual multicast configuration and cannot provide multicast services in non-multicast environments such as xDSL environments.

As modifying the router configuration has become very difficult, recently, a software-based multicast method has been developed that does not modify the router at all and uses only the software of the server and the end PC (Fig. 2). A multicast transmission server of a network (FIG. 2:50) in which one PC (FIG. 2:31) belonging to the cast network (FIG. 2:60, FIG. 2:70) has a multicast broadcast source (FIG. 2: 10) After receiving data in unicast from Fig. 2:11, and sprinkling the data by multicast on the broadcast network (Fig. 2:60) of Fig. 2:31, the PCs in the network (Fig. 2:32, Fig. 2:33) receives the transmitted data from the first PC (Fig. 2:31). In other words, if someone is already receiving data from their broadcasting network, the data is sent in repeater format. However, this method may cause performance degradation in asymmetric networks such as xDSL and cable due to the limitation of upload speed.

In order to solve the problems of the above software method, there is a method of providing a service by installing a dedicated multicast server. This method is similar to the software method above.

This approach allows end users (Figures 3:60 and 3:61) to connect to the nearest dedicated multicast server (Figure 3:31) and request multicast data. Then, the dedicated multicast server (FIG. 3:31) receives data from the higher dedicated multicast server (FIG. 3:30) and multiplies each user (FIG. 3:60, FIG. 3:61) using UDP tunneling. Send cast data. However, the present method can be installed and used only in a subnetwork such as B-RAS (Fig. 3:40) by a dedicated multicast server (Fig. 3:31). In this case, the maximum number of users depends on the upstream interface speed of B-RAS (Fig. 3: 100). Generally, up to 30,000 users can be connected to B-RAS, but if the upstream interface of B-RAS is 100Mbps, the number of users who can receive 1M stream service is limited to 100 users.

The present invention is a system for efficiently providing a multicast service in an xDSL network. The system consists of a multicast management server, a virtual multicast router and a multicast agent. The multicast management server manages the xDSL ID, level, and IP address for each virtual multicast router. This information is used to find the nearest virtual multicast router. Virtual multicast router is installed in Ethernet network through Fast Ethernet, Gigabit Ethernet interface, or ATM network or xDSL network through ATM interface to provide multicast service. The user then installs multicast agent software to send and receive multicast data through the virtual multicast router.

In the past, a virtual multicast router (FIG. 3:31) was installed as an Ethernet interface in the same subnetwork where B-RAS (FIG. 3: 40) was installed to provide multicast service in an xDSL network (FIG. 3: 90). The number of accessors is limited by the upstream connection speed (Fig. 3: 100) of B-RAS (Fig. 3: 40). To solve this problem, install a virtual multicast router in each DSLAM (Figure 3:50, Figure 3:51, Figure 3:52) under B-RAS, and configure the multicast transmission tree among them to provide more users. You should be able to provide services.

The virtual multicast router (Fig. 4:32, Fig. 4:33, Fig. 4:34) of the present invention has a DSLAM (Fig. 4:50, Fig. 4:51, Fig. 4 :) below the B-RAS (Fig. 4:40). At step 52), it operates through the IP over ATM protocol to provide a multicast service. Through this function, users of the xDSL network (Figs. 4:60 and 4:61) can be provided with multicast service without limiting the upstream connection speed of B-RAS.

1 is a multicast service providing environment in an xDSL network to which the system of the present invention is applied;

Figure 2 Conventional Multicast Network Block Diagram Using Software Technique

Fig. 3 A conventional multicast network block diagram using a dedicated multicast server.

Fig. 4 Multicast Deployment Environment Using Virtual Multicast Router in xDSL Network

The present invention is a system for efficiently providing a multicast service in an xDSL network (Fig. 1:80, Fig. 1: 90), a multicast management server (Fig. 1:20) and a virtual multicast router (Fig. 1:30, Fig. 1:31, Fig. 1: 32, Fig. 1: 33, Fig. 1: 34, Fig. 1: 35, Fig. 1: 36, Fig. 1: 37, Fig. 1: 38) and the multicast agent (Fig. 1: 60, Fig. 1:61, Fig. 1:62, Fig. 1:63, Fig. 1:64).

The multicast management server (Figure 1:20) is a virtual multicast router (Figure 1:30, Figure 1:31, Figure 1:32, Figure 1:33, Figure 1:34, Figure 1:35, Figure 1:36). FIG. 1:37, FIG. 1:38), and provides information necessary when the virtual multicast router or the multicast agent wants to search for the nearest upper virtual multicast router. The items that the multicast management server manages for the virtual multicast router are the xDSL ID, level, and IP address of the virtual multicast router. Here, the xDSL ID is the same ID for virtual multicast routers (Fig. 1:34, Fig. 1: 35, Fig. 1: 36, Fig. 1: 37, Fig. 1: 38) in the same xDSL network (Fig. 1:90). Becomes the same.

Levels are divided into three levels: Root, Intermediate, and Edge. The information of the virtual multicast router as described above is statically configured through a specific configuration file, or the virtual multicast router is configured to transmit the information periodically. To find the nearest virtual multicast router, we have a table that consists of the network address of the search requester (multicast agent or virtual multicast router) and the IP address of the virtual multicast router. The information in this table can be set statically or dynamically by the configuration file. The dynamically set method informs the multicast management server of the newly discovered result by the router discovery requester, and the management server organizes this information into corresponding tables.

Virtual multicast routers have the capability to transmit multicast data and provide fault tolerance and load sharing for reliability and stability. Virtual multicast routers (Figure 1:30, Figure 1:31, Figure 1:32, Figure 1:33, Figure 1:34, Figure 1:35, Figure 1:36, Figure 1:37, Figure 1:38) Can be installed in an Ethernet environment via a Fast-Ethernet or Gigabit Ethernet interface, or in an xDSL environment via an OC-3 or OC-12 class ATM interface. Virtual multicast routers (Fig. 1:32, Fig. 1: 33, Fig. 1: 35, Fig. 1: 36, Fig. 1: 37, and Fig. 1: 38) are used for installation in xDSL environment through ATM interface. It works by connecting with B-RAS (Fig. 1:40), and the installation location is directly connected with B-RAS or DSLAM (B: RAS 1:50, Fig. 1:51, Fig. 1:52). (Fig. 1:53, Fig. 1: 54, Fig. 1: 55, Fig. 1: 56).

Virtual multicast routers have the ability to receive multicast data and send the data to other multicast routers or multicast agents. This feature manages multicast membership for joining and leaving a specific multicast group. The membership information is used when the virtual multicast router or multicast agent connects to the virtual multicast router via dynamic tunneling and then attempts to join the multicast membership. Register by sending the multicast address and port number of the cast group. This membership information consists of a multicast group address, a multicast group port number, and a virtual multicast router or multicast agent address registered to the multicast group. When the multicast data is received later, the virtual multicast router transmits the data to the multicast agent or the virtual multicast router registered in the multicast group through UDP tunneling.

Each virtual multicast router constructs a hierarchical multicast tree to efficiently transmit multicast data, and transmits and receives multicast data through this tree. This tree information is the virtual multicast router IP address and the network address that the virtual multicast router will serve.

Hierarchical multicast trees on a general network can be configured in a static or dynamic manner. The static method is to write the tree information to a specific configuration file in advance.

On the other hand, in the dynamic method, each virtual multicast router dynamically searches the nearest upper virtual multicast router and constructs tree information based on the search results. For example, the virtual multicast router (FIG. 4:33) compares the RTT values of the two different virtual multicast routers (FIG. 4:32, 4:34) with the least number of virtual multicast routers (FIG. 4: 32). In contrast, the other virtual multicast routers (FIG. 4:34) compare the RTT values of the two different virtual multicast routers (FIG. 4:32, 4:33) with the least number of virtual multicast routers (FIG. 4:32). ). In addition, the multicast agent (FIG. 4:60) compares the RTT values of the virtual multicast routers (FIG. 4:32, FIG. 4:33, and 4:34) with the least number of virtual multicast routers (FIG. 4:33). Connect to

To construct a hierarchical multicast tree between virtual multicast routers in an xDSL network, compare the RTT values only for the virtual multicast routers higher than their own level and connect to the virtual multicast router with the lowest value. .

For example, in a single xDSL network (FIG. 1:90), a hierarchical multicast tree may exist in the same xDSL network (FIG. 1:90) of virtual multicast routers (FIG. 1:35, FIG. 1:36, FIG. 1 :). 37, Fig. 1: 38) is configured through the vertical relationship.

The multicast agent (Fig. 1:60, Fig. 1:61, Fig. 1:62, Fig. 1:63, Fig. 1: 64) is used by the user to receive the multicast data. The multicast agent retrieves the nearest virtual multicast router from the multicast management server, connects to it, and receives multicast data from the virtual multicast router. The received multicast data is delivered back to the multicast application using IP multicast.

To find the location of the nearest virtual multicast router, the multicast management server manages the network address of the multicast agent and the IP address of the virtual multicast router selected as the nearest router from the agent in a table. If the multicast agent requests a search, it retrieves matching data from the table.

At this time, if there is a match, it is notified that the search was made. If not, the agent is informed of the addresses of all multicast routers. The multicast agent then checks the RTT between the virtual multicast routers and selects the smallest RTT. The selected information is then cached by other multicast agents on the same subnetwork by notifying the multicast management server of the results for quick retrieval. If a search request comes in later on the same subnetwork, the multicast management server will notify you via the cached information.

If a user on the xDSL network makes a search request and the virtual multicast router closest to the user is installed in the xDSL network, the user does not use the information cached from the multicast management server, but only the information of the virtual multicast routers. Take and connect to the fewest virtual multicast routers by examining each RTT value. Do not cache this search result.

In order to provide multicast service efficiently in xDSL network, virtual multicast router is installed in sub-network such as B-RAS, and one virtual multicast router is installed in DSLAM inside B-RAS for multicast environment. It is ideal to build.

The present invention is a system for efficiently providing a multicast service in an xDSL (ADSL, SDSL, VDSL, HDSL) network, and can effectively provide a multicast application service such as Internet broadcasting. The present invention is insufficient to provide a practical multicast service because the existing multicast application method is dependent on the service delivery level of the B-RAS upstream connection speed in the xDSL network, while the system is multicast to the DSLAM closest to the user By installing a router, you can serve faster and more users. That is, the multicast service can be provided in the xDSL network.

Currently, the multicast service providing technology is underdeveloped in the world, so that it can preoccupy the multicast service market later, and the overseas sale of the technology can be promoted, and as a result, the domestic developed Internet environment can be promoted abroad.

This technology is a new technology that provides the most efficient multicast technology in the xDSL network, which is the most difficult to apply the existing multicast technology.

Claims (6)

Virtual multicast router with multicast transmission tree function and multicast data transmission / reception function for transmitting multicast data, multicast receiving multicast data transmitted from virtual multicast router and transmitting the data to user's application Agents, multicast management server that manages the information needed to find the nearest virtual multicast router from the user, to efficiently transmit multicast data in xDSL (ADSL, SDSL, VDSL, HDSL) networks How and its system The method of claim 1, Connect all virtual multicast routers installed inside the xDSL network to B-RAS or DSLAM. And how to configure the network to efficiently transmit multicast data in xDSL network by constructing hierarchical multicast transmission tree between virtual multicast routers The method of claim 2, To receive multicast data from upper virtual multicast router in xDSL network and send data to multicast agent, connect OC-3 and OC-12 class ATM interface to DSLAM closest to user or connect to B-RAS. Virtual multicast router for xDSL for multicast data transmission over OC-3, OC-12, Fast Ethernet, and Gigabit Ethernet interfaces To transmit multicast data in xDSL network A) Function to connect with B-RAS using IP over ATM protocol B) periodically send your xDSL ID, level, and IP address for location search C) A function of constructing hierarchical multicast transmission tree to efficiently transmit multicast data D) Search for the nearest upper multicast router, receive data from the router, and send data to the lower multicast router or multicast agent. E) Fault Tolerance to connect to another multicast router if the upper multicast router is down F) Load sharing function connecting to multicast router with the least number of users when there are multiple virtual multicast routers in the same xDSL network. Virtual multicast router with To construct hierarchical multicast transmission tree structure between virtual multicast routers to transmit multicast data in xDSL network A) How to statically set hierarchical tree relationship between multicast routers in multicast management server B) Dynamically setting hierarchical tree relationships between multicast routers The method of claim 5 In order for all virtual multicast routers in the same xDSL network to dynamically establish hierarchical tree relationships between each multicast router, all virtual multicast routers register their xDSL ID, level, and their IP addresses with the multicast management server. The virtual multicast router retrieves the addresses of the virtual multicast routers one level higher than its own level with the same xDSL ID to connect to the nearest upper virtual multicast router from the multicast management server and rounds the RTT between each multicast router. To the multicast router with the lowest Trip Time). How to dynamically configure hierarchical tree relationships by registering the results with the multicast management server