KR20100002657A - Apparatus for internet group management protocol proxy - Google Patents

Abstract

PURPOSE: An apparatus for IGMP proxy is provided to distribute the load of upstream interfaces or multicast routers connected to the upstream interfaces, thereby providing stable multicast services. CONSTITUTION: An IGMP(Internet Group Management Protocol) proxy device(310) comprises N upstream interfaces(u1,u2,u3), one or more downstream interfaces(d1,d2) and a controller. In order to equalize the load of the upstream interfaces, the controller switches connection relation among the upstream interfaces and the down stream interface. The IGMP proxy device stores merge information about each of the upstream interfaces in a membership database(350).

Description

Internet group management protocol proxy device {apparatus for Internet Group Management Protocol Proxy}

The present invention relates to an IGMP proxy device, and more particularly, but not exclusively, to an IGMP proxy device that can provide a stable multicast service by distributing load.

Since the Internet Group Management Protocol (IGMP) proxy can forward multicast packets only with IGMP membership information, the Multicast Routing Protocol: Hereinafter, MRP) is not necessarily required. Therefore, it is possible to reduce the complicated calculation performance by the MRP, even if different MRP is used.

1 and 2 are conceptual diagrams for explaining a general IGMP proxy.

IGMP proxy device 170 has one upstream interface 110 and downstream interfaces 120 and 130.

The upstream interface 110 is an interface connected to the multicast router 100 located above, and serves as a host of IGMP.

The first downstream interface 120 and the second downstream interface 130 are interfaces connected to the first subnet 150 and the second subnet 160, respectively, and serve as routers of IGMP. At least one host (not shown) is included in the subnets 150 and 160, and a switch or the like may be included in some cases.

The first and second downstream interfaces 120 and 130 manage the first and second subscription lists 122 and 132, respectively. Here, the subscription lists 122 and 132 are information including membership of the subnets 150 and 160 connected with the downstream interfaces 120 and 130, and the membership is a multicast group serving the corresponding subnets 150 and 160. It means an address. That is, membership means a multicast group joined by the corresponding subnets 150 and 160.

The membership database 140 is a database in which the subscription lists 122 and 132 of the downstream interfaces 120 and 130 are merged. As shown in FIG. 1, a set of membership records is stored as an entry. Here, the membership record includes a multicast group address as shown in FIG. 1, and may additionally include a filter mode and a source list.

FIG. 2 shows, in the state of FIG. 1, when a host (not shown) in the first subnet 150 transmits an IGMP report packet to receive a multicast service of a multicast group address 225.1.2.1. It is a conceptual diagram for explaining the operation of the IGMP proxy device 170. For convenience, the reference numerals in FIG. 2 refer to the same reference numerals in FIG. 1.

In FIG. 2, when the first downstream interface 120 receives an IGMP report packet from the first subnet 150, the first subscription list 122 is updated. Here, examples of the IGMP report packet include an IGMP membership report packet for notifying a multicast group address that is desired to be serviced, and an IGMP leave report packet for notifying that the service is not provided for the multicast group address. However, the present invention is not limited thereto.

The updated subscription information is reflected in the membership database 140, and the updated portion of the membership database 140 (i.e., the membership record) is transmitted through the upstream interface 110 in the form of an IGMP report packet. Is passed to.

Since the IGMP report packet in FIG. 2 is intended to receive the service of the multicast group address 225.1.2.1, the multicast router 100 which has received it forwards the packet corresponding to the multicast group address to the IGMP proxy device 170. do. As a result, a host (not shown) in the first subnet 150 requesting the service receives the corresponding multicast packet through the downstream interface 120 of the IGMP proxy device 170.

On the other hand, the above-described IGMP proxy device is designed on the assumption of a simple tree topology environment that does not require the exchange of routing information, and thus has one upstream interface. In this case, when there is a heavy load on the upstream interface or the multicast router connected to the upstream interface, a situation may occur in which a stable multicast service cannot be provided.

The technical problem to be achieved by the present invention is to provide an IGMP proxy device that can distribute the load to provide a stable multicast service.

In order to achieve the above technical problem, a first aspect of the present invention provides an N (natural number greater than 1) upstream interfaces; At least one downstream interface; And a control unit for switching a connection relationship between the upstream interfaces and the at least one downstream interface to equalize the load of the upstream interfaces.

In order to achieve the above technical problem, a second aspect of the present invention provides an N (natural number greater than 1) upstream interfaces; At least one downstream interface; Among the upstream interfaces, a control unit for detecting M (natural numbers greater than 1, less than or equal to N) usable upstream interfaces, and switching a connection relationship between the usable upstream interfaces and the at least one downstream interface. It provides an Internet group management protocol proxy device.

Embodiments of the present invention presented above may have an effect including the following advantages. However, all the embodiments of the present invention are not meant to include them all, and thus the scope of the present invention should not be understood as being limited thereto.

According to an embodiment of the present invention, it is possible to provide a stable multicast service by balancing the load of the upstream interface or the multicast router connected to the upstream interface.

In addition, according to an embodiment of the present invention, even if the number of available upstream interfaces is changed, signaling (eg, number of transmission of IGMP report packets, routing information exchange between multicast routers, etc.) and database changes (eg, a membership database) may be performed. The amount of content being updated, etc. can be minimized.

Since descriptions of embodiments of the present invention are merely illustrated for structural to functional descriptions of the present invention, the scope of the present invention should not be construed as limited by the embodiments described in the present invention. That is, the embodiments of the present invention may be variously modified and may have various forms, and thus, it should be understood that the present invention includes equivalents capable of realizing the technical idea of the present invention.

On the other hand, the meaning of the terms described in the present invention will be understood as follows.

Terms such as "first" and "second" are intended to distinguish one component from another component, and the scope of the present invention should not be limited by these terms. For example, the first component may be named a second component, and similarly, the second component may also be named a first component.

The term “and / or” should be understood to include all combinations that can be presented from one or more related items. For example, "first item, second item, and / or third item" means "at least one or more of the first item, second item, and third item", and means first, second, or third item. A combination of all items that can be presented from two or more of the first, second and third items as well as the third item.

When a component is referred to as being "connected" to another component, it should be understood that there may be other components in between, although it may be directly connected to the other component. On the other hand, when a component is said to be "directly connected" to another component, it should be understood that there is no other component in between. On the other hand, other expressions describing the relationship between the components, such as "between" and "immediately between" or "neighboring to" and "directly neighboring to", should be interpreted as well.

Singular expressions described herein are to be understood to include plural expressions unless the context clearly indicates otherwise, and the terms "comprise" or "having" include elements, features, numbers, steps, operations, and elements described. It is to be understood that the present invention is intended to designate that there is a part or a combination thereof, and does not exclude in advance the possibility of the presence or addition of one or more other features or numbers, steps, actions, components, parts or combinations thereof. .

Each step described in the present invention may occur out of the stated order unless the context clearly dictates the specific order. That is, each step may occur in the same order as specified, may be performed substantially simultaneously, or may be performed in the reverse order.

Unless otherwise defined, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and shall be interpreted as having ideal or overly formal meanings unless expressly defined in this application. Can't be.

3A to 3C are diagrams for describing an operation of an IGMP proxy device according to an embodiment of the present invention.

3A is a view for explaining the general operation of the IGMP proxy device 310, FIG. 3B is a view for explaining the operation after the number of upstream interfaces available in the situation of FIG. 3A is reduced, and FIG. 3C is a view of FIG. A diagram for describing an operation after an increase in the number of upstream interfaces available in a situation.

3A to 3C, a first multicast router 300, a second multicast router 302, a third multicast router 304, and an IGMP proxy device 310 are shown, and the IGMP proxy device 310 is shown. It is shown to include upstream interfaces u1, u2, u3, downstream interfaces d1, d2, subscription lists 340, 342, and membership database 350.

The interior of the IGMP proxy device 310 shown in Figures 3a to 3c can be implemented in various ways, in the present specification, for convenience, it is assumed that a control unit (not shown), which is a module, performs a switching operation according to the present invention. Will be explained.

Referring to Figure 3a, the operation of the IGMP proxy device according to an embodiment of the present invention will be described.

The IGMP proxy device 310 manages subscription lists 340 and 342 corresponding to each of the downstream interfaces d1 and d2.

When the membership database 350 is updated according to the packet reception at the downstream interfaces d1 and d2, the IGMP proxy device 310 transmits an IGMP report packet to a corresponding multicast router 300, 302, 304, or upstream. In order to transmit the multicast packets received from the interfaces u1, u2 and u3 to the host (not shown), the connection relationship between the upstream interfaces u1, u2 and u3 and the downstream interfaces d1 and d2 is switched. . For example, when receiving an IGMP report packet transmitted from a host (not shown) at the first downstream interface d1, the IGMP proxy device 310 updates the first subscription list 340 and then updates the updated contents. To the membership database 350. Herein, the connection relationship means selection of upstream interfaces u1, u2, and u3 that are in charge of IGMP processing associated with multicast group addresses subscribed to the downstream interfaces d1 and d2. This selection method will be described later with reference to FIG. 4A.

The IGMP proxy device 310 stores / manages the merged information for each of the upstream interfaces u1, u2, and u3 in the membership database 350. Here, the merging information is information obtained by merging subscription lists 340 and 342 of at least one downstream interface d1 and d2 connected to the corresponding upstream interfaces u1, u2 and u3. Referring to FIG. The merge information of the upstream interface u1 includes the multicast group address 225.1.1.1, the merge information of the second upstream interface u2 includes the multicast group address 225.1.1.2, and the merge information of the third upstream interface u3. The merge information includes the multicast group address 225.1.1.3.

As shown in FIG. 3A, the IGMP report packet associated with 225.1.1.1 is delivered to the first multicast router 300 via the first upstream interface u1 and the IGMP report packet associated with 225.1.1.2 and 225.1.1.3. The IGMP report packet associated with is forwarded to the second multicast router 302 and the third multicast router 304, respectively. As a result, a host (not shown) connected with the first downstream interface d1 may receive the multicast service packet related to 225.1.1.1 via the first multicast router 300 and the first upstream interface u1. It is possible to receive the multicast service packet associated with 225.1.1.3 through the third multicast router 304, the third upstream interface u3.

Referring to Figure 3b, the operation of the IGMP proxy device according to an embodiment of the present invention will be described. FIG. 3B is a view for explaining an operation in which the IGMP proxy device 310 operating as shown in FIG. 3A detects the use of the second upstream interface u2 and copes with it.

An example of the case where the second upstream interface u2 is not available may include, but is not limited to, a case where the equipment manager arbitrarily removes the connection of the upstream interface when an upstream interface-related failure occurs. Here, an example of an upstream interface-related failure may include a failure in a multicast router connected to an upstream interface, a failure of a link between the multicast router and an IGMP proxy device, or an failure of the upstream interface itself. It is not necessarily limited thereto.

Here, as an example of the method of detecting the unavailableness, the multicast packet of the group checked through the status parameters of the upstream interfaces u1, u2, and u3 or joined to the upstream interfaces u1, u2 and u3 may be used. A method of detecting a failure through a method of checking whether it has not been received for a certain time or a method of detecting a failure according to an input of a device manager is not limited thereto.

When the IGMP proxy device 310 detects that the second upstream interface u2 is unavailable, at least the IGMP proxy device 310 should distribute the merged information of the second upstream interface u2 to the remaining upstream interfaces u1 and u3. As an example, it can be seen that 225.1.1.2, which was in charge of the second upstream interface u2, has been moved to merge information of the third upstream interface u3.

After updating the membership database 350 as described above, the IGMP report packet containing the updated contents is reported to the corresponding router through the corresponding upstream interface. According to FIG. 3B, since the merge information of the third upstream interface u3 is updated, An IGMP report corresponding to 225.1.1.2 is forwarded to the third multicast router 304 via the third upstream interface u3. As a result, in FIG. 3A, the host (not shown) under the second downstream interface d2, which has received 225.1.1.2 related service through the second multicast router 302 and the second upstream interface u2, is connected to the third multicast router. Through the cast router 304 and the third upstream interface u3, it is possible to continuously receive 225.1.1.2 related services.

Referring to Figure 3c, the operation of the IGMP proxy device according to an embodiment of the present invention will be described. FIG. 3C is a diagram for describing an operation in which the IGMP proxy device 310 operating as shown in FIG. 3D detects and copes with the availability of the second upstream interface u2.

Here, an example of an increase in the number of available upstream interfaces may include a case in which an equipment manager arbitrarily connects to a new upstream interface when it detects that an upstream interface-related failure is resolved. no.

When the IGMP proxy device 310 detects the availability of the second upstream interface u2, the IGMP proxy device 310 should distribute the multicast group addresses included in the membership database 350. The embodiment of FIG. 3C illustrates the third upstream interface u3. It can be seen that 225.1.1.2, which was in charge of), has been moved to the merge information of the second upstream interface u2.

After updating the membership database 350 as described above, the IGMP report packet including the updated contents is reported to the corresponding multicast router through the corresponding upstream interface. According to FIG. 3C, merge information of the second upstream interface u2 is stored. Since it has been updated, an IGMP report corresponding to 225.1.1.2 is forwarded to the second multicast router 302 via the second upstream interface u2. As a result, in FIG. 3B, the host (not shown) under the second downstream interface d2, which has received the 225.1.1.2 related service through the third multicast router 304 and the third upstream interface u3, is assigned a second multicast. Through the router 302 and the second upstream interface u2, 225.1.1.2 related services can be continuously received.

Meanwhile, since the merge information of the third upstream interface u3 is also updated, an operation of forwarding the IGMP leave report packet associated with the deleted multicast group address 225.1.1.2 to the third multicast router 304 may also be performed. Anyone working in this field can fully understand.

As described above, by providing a plurality of upstream interfaces in an IGMP proxy environment and forwarding the IGMP report packet to the corresponding multicast router through different upstream interfaces according to the multicast group, the IGMP proxy device and the host can transmit the multicast packet. It can be distributed / received. This method has an effect of providing load balancing and providing a stable multicast service.

One embodiment of such a load equalization method is as follows.

When the IGMP Proxy device receives the IGMP Report packet, the hash value is obtained through a hash function using the multicast group address included in the received IGMP Report packet as a key value, and the hash value is hashed. It can be applied to the threshold algorithm to determine the upstream interface responsible for the multicast group address. By transmitting the IGMP report packet received through the determined upstream interface, it is possible to load balance the multicast routers connected to the IGMP proxy device.

An example of a hash function for determining an upstream interface is a cyclic redundancy check (CRC) operation. For example, applying a CRC-8 operation to a multicast group address included in a received IGMP report packet results in an 8-bit hash value, which is used to determine the hash value region. As will be described later with reference to FIG. 5, a plurality of hash value regions are mapped one-to-one to a plurality of upstream interfaces.

When increasing / decreasing the available upstream interface, the IGMP proxy device must continue to provide existing multicast services while minimizing the impact on the propagation path of the existing multicast packets. Otherwise, multicast routers belonging to the network cause complex problems such as frequent rerouting and thus routing information exchange. To minimize this, the IGMP Proxy device uses a hash-threshold algorithm in accordance with one embodiment of the present invention.

The characteristics of this hash-threshold algorithm are as follows.

For example, if there are five upstream interfaces available in an IGMP proxy device and the number of hash values obtained through the hash function is 40 (that is, the size of the hash value space is 40), the hash value regions Each matches one-to-one with a path (ie, an available upstream interface). In this case, 40/5 hash values are included in each hash value region as shown in FIG. 4A.

Referring to FIG. 4A, it can be seen that eight hash values are allocated per hash value region, and that five hash value regions have the same region size 8. FIG.

When five paths are available as shown in FIG. 4A and an unusable event occurs in one path (eg, path 3), the path is changed as shown in FIG. 4B.

Referring to FIG. 4B, unlike FIG. 4A, not only hash values belonging to hash value region 1 but also 1/4 of hash values belonging to hash value region 2 are mapped to path 1. The rest of the hash value region is similarly described. That is, the total disruption is 1/5 x (1/4 + 1/2 + 1/2 + 1/4) = 3/10 according to the deletion of the upstream interface corresponding to the hash value region 3 of the various paths.

This characteristic of the hash-threshold algorithm is established when the number of available upstream interfaces changes from N-> N-1, N-> N + 1, and the total disruption is between a minimum of 1/4 and a maximum of 1/2. do

5 is a view for explaining a determination process of the upstream interface according to an embodiment of the present invention.

When the IGMP report packet 500 is received at the downstream interface of the IGMP proxy device, the IGMP proxy device performs CRC-8 operation on the multicast group address included in the IGMP report packet 500 to obtain an 8-bit CRC value. Here, the CRC-8 operation and the 8-bit CRC value correspond to the above-described hash function and the hash value.

Reference numeral 510 denotes a space, ie, a hash value space, for all CRC values that can be obtained through a CRC-8 operation, and the hash value space 510 is divided by the number of available upstream interfaces so that the first to fourth areas are divided. Is generated. The CRC value obtained by the above method belongs to any one of the first to fourth areas, and the IGMP report packet 500 is transmitted to the multicast router through an upstream interface mapped to the area.

The inventors of the present invention have been described with reference to the embodiments shown in the drawings for clarity, but this is merely exemplary, and those skilled in the art may various modifications and other equivalent embodiments therefrom. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

Embodiments of the present invention presented above may have an effect including the following advantages. However, all the embodiments of the present invention are not meant to include them all, and thus the scope of the present invention should not be understood as being limited thereto.

According to an embodiment of the present invention, it is possible to provide a stable multicast service by balancing the load of the upstream interface or the multicast router connected to the upstream interface.

In addition, according to an embodiment of the present invention, even if the number of available upstream interfaces is changed, signaling (eg, number of transmission of IGMP report packets, routing information exchange between multicast routers, etc.) and database changes (eg, a membership database) may be performed. The amount of content being updated, etc. can be minimized.

1 and 2 are conceptual diagrams for explaining a general IGMP proxy.

3A to 3C are diagrams for describing an operation of an IGMP proxy device according to an embodiment of the present invention.

4A and 4B illustrate a hash function and a hash-threshold algorithm according to an embodiment of the present invention.

5 is a view for explaining a determination process of the upstream interface according to an embodiment of the present invention.

Claims (7)

N (natural numbers greater than 1) upstream interfaces; At least one downstream interface; And And a control unit for switching a connection relationship between the upstream interfaces and the at least one downstream interface to equalize the load of the upstream interfaces. The method of claim 1, wherein the control unit, When a packet is received at the at least one downstream interface and an event for transmitting an IGMP report packet is generated, a hash-threshold algorithm is applied to a multicast group address included in the received packet to apply one of the plurality of upstream interfaces. Select one, and transmit the IGMP report packet via the selected upstream interface. The method of claim 2, wherein the control unit Among the upstream interfaces, if there are M (natural numbers greater than 1 and less than or equal to N) available upstream interfaces, Mapping M regions obtained by dividing a space of hash values into M one-to-one to the available upstream interfaces, And transmitting the IGMP report packet through an upstream interface mapped to an area including a hash value calculated from the multicast group address among the areas. The method of claim 3, The hash value is a CRC value obtained by applying a CRC operation to the multicast group address, And the space of hash values is a space including CRC values obtained by the CRC operation. The method of claim 2, A membership database for storing merge information for at least one of the upstream interfaces, The event includes a case in which the multicast group address included in the received packet is not in the membership database, The merging information is information obtained by merging subscription lists of at least one downstream interface connected with the corresponding upstream interface. And the control unit includes the multicast group address in merge information of the selected upstream interface. N (natural numbers greater than 1) upstream interfaces; At least one downstream interface; Among the upstream interfaces, a control unit for detecting M (natural number greater than 1, less than or equal to N) usable upstream interfaces, and switching the connection relationship between the available upstream interfaces and the at least one downstream interface; And an Internet group management protocol proxy device. The method of claim 6, A membership database for storing merge information for at least one of the upstream interfaces, The control unit may update the membership database so that the load of the available upstream interfaces is equalized by using a hash-threshold algorithm when an event in which the value of M changes is generated, and corresponding IGMP through the upstream interface having the updated merge information. Send a report packet, And the merging information is information obtained by merging subscription lists of at least one downstream interface connected with the corresponding upstream interface.

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