KR102639919B1 - Method and apparatus for processing multicast for each service in passive optical network - Google Patents

Abstract

The present invention relates to a multicast processing method and device for each service in a passive optical network, and more specifically, to a single session from an OLT to an ONT/ONU according to an IGMP message received from each ONU/ONT in the passive optical network (PON). When forwarding multicast traffic in a mode including single-session, aggregate-session, or a combination thereof, a method of performing channel allocation for each service using multicast LLID (Multicast LLID: mLLID); It's about the device

Description

Multicast processing method and device for each service in a passive optical network {METHOD AND APPARATUS FOR PROCESSING MULTICAST FOR EACH SERVICE IN PASSIVE OPTICAL NETWORK}

The present invention relates to a multicast processing method and device for each service in a passive optical network, and more specifically, to a single session between an OLT and an ONT/ONU according to an IGMP message received from each ONU/ONT in the passive optical network (PON). When forwarding multicast traffic in a mode including single-session, aggregate-session, or a combination thereof, a multicast LLID (Multicast LLID, mLLID) is assigned to each service and distinguished by the mLLID. It relates to a method and device for performing channel allocation for each service.

As the spread of high-speed Internet has expanded, various multimedia services, including existing broadcasting services, have recently been provided through high-speed Internet. In particular, UHD (Ultra High Definition) video services require processing of traffic up to gigabit level, so smooth service is possible only when network lines and network equipment are upgraded.

The system that reflects these advanced network lines and equipment is the Passive Optical Network (PON) system, which includes Optical Line Termination (OLT), Optical Network Unit (ONU)/Optical Network Terminal (ONT), and Optical Distribution Network (ODN). ) and provides subscribers with a variety of multimedia services such as broadcasting, Internet, or voice at high speed.

In this passive optical network system, in order to accommodate various types of services and a plurality of subscribers, and in particular to stably forward multimedia service traffic to the subscribers through broadcasting (broadcasting), multicasting, or unicasting, the bandwidth required for the service traffic It is very important to allocate and use effectively.

However, in order to provide broadcasting (or multicast) services, the conventional passive optical network system is configured to provide services to desired subscribers by allocating channels according to a preset configuration for each subscriber.

Like the conventional passive optical network system, it is very simple to provide multimedia services by allocating broadcasting channels according to a preset configuration, but the types and bandwidths of services that must be delivered through the actual subscriber network are very diverse, and the bandwidth desired by the subscriber is very diverse. Since the configuration of the service is variable each time, dynamically setting the configuration and applying it in real time is very important in efficiently utilizing bandwidth. In other words, since a wide variety of multimedia services such as CATV, VoD (SD, HD, UHD level, etc.), Internet broadcasting (IPTV), and data broadcasting are delivered through the subscriber network, the configuration that provides the service must be dynamically set according to the combination of these. It is necessary to do

In addition, when providing a multicast service for each subscriber, if a service with a different bandwidth is desired between subscribers, the multicast service must be provided according to the service with the maximum bandwidth among the subscribers, so even if traffic is forwarded by multicast, the bandwidth There is a lot of waste.

Despite this situation, in the conventional passive optical network system, channels are allocated to subscribers according to the configuration of a predetermined multimedia session, and if no more channels can be allocated, the user's IGMP join request must be rejected from then on. , In addition, if there is a difference in the bandwidth for each service of each individual user (subscriber), traffic must be transmitted according to the maximum bandwidth, so network resources cannot be used as efficiently. In other words, there is a problem in that network resources cannot be utilized efficiently according to the conventional technology.

In particular, in recent years, the bandwidth of multimedia services has become increasingly broadband and has also become more diverse due to the increase in services through wireless networks. Therefore, fixed allocation of bandwidth or channels in a passive optical network system is bound to encounter various limitations. does not exist.

Therefore, in the present invention, when the OLT receives an IGMP (Internet Group Management Protocol) message from the ONU/ONT, it includes an aggregate-session, a single-session, or a combination thereof depending on the dynamically managed configuration. We want to provide a multicast service by allocating channels for each service with the same bandwidth as each service, depending on the mode.

For example, when a passive optical network system accepts a CATV broadcasting service, the passive optical network system performs multicast control according to a dynamically adapted configuration and provides broadcasting services for each service. In other words, when a specific subscriber connects to the ONU/ONT and requests each service, the ONU/ONT requests IGMP join to the OLT. Accordingly, the OLT subdivides the services and bandwidth for the IGMP and distributes the bandwidth and service. By grouping based on broadcasting channels and then assigning broadcasting channels according to multicast sessions, subscribers can watch broadcasts for each service they want.

Next, we will briefly describe the prior art existing in the technical field of the present invention, and then describe the technical details that the present invention seeks to achieve differently compared to the prior art.

First, US Patent No. 8711872 (April 29, 2014) relates to a data distribution device and method, and discloses a data distribution method and device for transmitting multicast data to terminals belonging to a multicast group.

Additionally, US Patent No. 8254386 (2012.08.28) relates to a method of implementing multicast through a passive optical network.

In the prior art, the IGMP message is analyzed, the source address and destination address included in the IGMP are extracted, the VID is combined with the extracted source address and destination address, the addresses and VLAN are registered in the mapping table, and the destination Multicast data is forwarded to the address. The above prior art only describes multicast forwarding according to IGMP, and does not suggest anything about generating and allocating mLLIDs for each service for multicast forwarding of the present invention and controlling the configuration for overall channel allocation in real time. There is no description.

On the other hand, the present invention receives IGMP from an ONT/ONU at the OLT of a passive optical network (PON), and accordingly provides a single-session, an aggregate-session, or a combination thereof to the ONT/ONU. When performing multicast traffic forwarding in a mode including, assigning a multicast LLID to each service, dynamically determining channel allocation for each service by LLID, and controlling the overall bandwidth limit in real time; The goal is to provide that device. In reality, the types and bandwidth of services that must be delivered through the optical subscriber network are very diverse, and the configuration of the service desired by the subscriber is variable each time, so the configuration is dynamically set for each service and applied in real time, such as CATV, VoD (SD, In delivering a wide variety of multimedia services such as HD, UHD level, Internet broadcasting (IPTV), and data broadcasting through a subscriber network, there is an advantage in efficiently utilizing bandwidth.

The present invention was created to solve the problems of the prior art described above. The present invention receives the IGMP requested from the subscriber terminal in a passive optical subscriber network (PON) through the ONT/ONU, and thus performs a single session with the ONT/ONU. , When forwarding multicast traffic in a mode including collective session or a combination thereof, multicast LLID is assigned to each service, channel allocation is performed for each service identified by the multicast LLID, and traffic is managed to be forwarded. The purpose is to efficiently utilize bandwidth through control.

In addition, the present invention efficiently utilizes bandwidth by dynamically managing in real time the configuration of the bandwidth limit to be allocated to the mode including overall single session, collective session, or a combination thereof when performing channel allocation through the multicast LLID. The purpose is to

In addition, the present invention dynamically performs channel allocation for each service, so that even if the subscriber or channel is the same, if the configuration of the service provided to the subscriber through the corresponding channel requires a different bandwidth, the configuration also requires a separate mLLID. The purpose is to reduce bandwidth loss by allocating and classifying each service into the different services and allocating bandwidth in real time according to the configuration.

A service-specific multicast processing method in a passive optical network according to an embodiment of the present invention includes the steps of receiving an IGMP join request from an ONU/ONT that has received an IGMP join request from a subscriber terminal (CPE), and executing the received IGMP join request. Processing and allocating a multicast LLID to each service according to the processed IGMP, and performing channel allocation for each service identified by the multicast LLID.

In addition, the service-specific multicast processing method further includes registering an mLLID in the ONU/ONT, and in the case of an aggregate session, registering an mLLID in the ONU/ONT in advance before the IGMP join request is received, and registering the mLLID in the ONU/ONT in advance of the single session. In this case, the mLLID is registered in the ONU/ONT after the IGMP join request is received.

In addition, the multicast processing method for each service further includes registering an mLLID in the ONU/ONT when the ONU/ONT is connected to the OLT and determining whether it is a collective session or a single session from the processed IGMP join request, wherein the determination Accordingly, in the case of the collective session, the entire session limit is checked, and in the case of the single session, the entire EIR value of the channel is checked to see if it is within the range of the bandwidth allocated for multicast admission control, and does not deviate from the session limit and the range. If not, the service is performed for each session.

In addition, the service-specific multicast processing method includes performing IGMP decoding, group membership lookup, and multicast profile lookup for the IGMP join request, generating source and group IP addresses from the IGMP, and source and It is characterized in that it further includes the step of forwarding multicast traffic to the group IP address.

In addition, the step of performing channel allocation for each service is characterized by performing dynamic IP multicast control with ONU/ONT by adding an OAM message including the mLLID, source and group IP addresses, and client MAC address.

In addition, the step of performing channel allocation for each service is characterized by classifying the service as a different service and assigning an mLLID if the bandwidth occupied by the service is different even if the subscribers or channels are the same.

In addition, in a passive optical network according to an embodiment of the present invention, the service-specific multicast processing device receives an IGMP join request from an ONU/ONT that has received an IGMP join request from a subscriber terminal (CPE), and responds to the received IGMP join request. It is characterized by including an IGMP processing unit and a multicast processing unit that performs channel allocation for each service using a multicast LLID (mLLID) according to the processed IGMP.

In addition, the IGMP processing unit generates an mLLID and registers the mLLID in the ONU/ONT, and in the case of an aggregate session, the multicast processing unit generates an mLLID in the ONU/ONT in advance before the IGMP join request is received. In the case of a single session, the mLLID is registered in the ONU/ONT after the IGMP join request is received.

In addition, the IGMP processing unit further includes a role of registering an mLLID in the ONU/ONT when the ONU/ONT is connected to the OLT, and the multicast processing unit determines whether it is a collective session or a single session from the processed IGMP join request. It further includes a process, and according to the above determination, in the case of the collective session, the total session limit is checked, and in the case of the single session, the total EIR value of the channel is checked to see if it is within the range of the bandwidth allocated for multicast admission control, It is characterized in that the service for each session is performed if it does not exceed the session limit and the range.

In addition, the IGMP processing unit further includes performing IGMP decoding, group membership lookup, and multicast profile lookup for the IGMP join request, and the multicast processing unit generates a source and group IP address from the IGMP, and , characterized in that it further includes the process of forwarding multicast traffic to the source and group IP addresses.

In addition, the multicast processing unit may further include performing dynamic IP multicast control with the ONU/ONT by adding an OAM message including the mLLID, source and group IP addresses, and client MAC address.

In addition, the multicast processing unit that performs channel allocation for each service classifies the service as a different service and assigns an mLLID if the bandwidth occupied by the service is different even if the subscribers or channels are the same.

The present invention is a mode in which the OLT includes a single-session, aggregate-session, or a combination of these to the ONT/ONU according to the IGMP message received from each ONU/ONT in a passive optical network (PON). When forwarding multicast traffic, channel allocation for each service is performed using multicast LLID (Multicast LLID: mLLID), and the configuration settings can be changed in real time, thereby controlling the overall bandwidth limit in real time. In reality, the types and bandwidth of services that must be delivered through the optical subscriber network are very diverse, and the configuration of the service desired by the subscriber is variable each time, so the configuration is dynamically set for each service and applied in real time, such as CATV, VoD (SD, In delivering a wide variety of multimedia services such as HD, UHD level, Internet broadcasting (IPTV), and data broadcasting through a subscriber network, there is an advantage in efficiently utilizing bandwidth.

1 is a conceptual diagram illustrating the concept of performing multicast processing in a passive optical network according to an embodiment of the present invention.
Figure 2 is a flowchart showing an OLT multicast processing method in a passive optical network according to an embodiment of the invention.
Figure 3 is a block diagram showing the configuration of an OLT multicast processing device in a passive optical network according to an embodiment of the present invention.
Figure 4 is a flowchart showing a procedure for forwarding multicast traffic according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the present invention with reference to the accompanying drawings. The same reference numerals in each drawing indicate the same member. In addition, specific structural and functional descriptions of the embodiments of the present invention are merely illustrative for the purpose of explaining the embodiments of the present invention, and unless otherwise defined, all terms used herein, including technical or scientific terms, are provided. They have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having meanings consistent with the meanings they have in the context of the related technology, and unless clearly defined in this specification, should not be interpreted in an idealized or overly formal sense. No.

1 is a conceptual diagram illustrating the concept of performing multicast processing in a passive optical network according to an embodiment of the present invention.

As shown in Figure 1, a passive optical network (PON) system consists of an OLT (10), at least one ONU/ONT (20), and a 1:N passive splitter (ODN), and provides CATV, It provides various multimedia services such as VoD (SD, HD, UHD level, etc.), Internet broadcasting (IPTV), and data broadcasting at high speed.

When a multicast request packet comes from the ONU/ONT 20 through IGMP, the service-specific multicast processing device 100 according to the present invention internally requests the packet from the service network through IGMP Join/Leave, IGMP Snooping, etc. , Multimedia services are achieved by statically or dynamically allocating a multicast channel for this and then assigning an mLLID to the ONU/ONT and forwarding the packet.

However, in the present invention, unlike the prior art, the IGMP requested from the subscriber terminal is received through the ONT/ONU, and multicast traffic is forwarded to the ONT/ONU in a mode including single session, aggregate session, or a combination thereof. In this case, it is possible to utilize bandwidth efficiently by allocating a multicast LLID to each service, performing channel allocation for each service classified by the multicast LLID, and managing and controlling traffic forwarding.

In addition, by performing channel allocation for each service, even if the subscriber or channel is the same, the bandwidth provided by the service transmitted to the subscriber through the channel frequently changes (i.e., the bandwidth frequently changes depending on the content provided by the service). For example, if the service provides high-definition movies, a high bandwidth is required, and if it provides 2D animation, a relatively low bandwidth is required.) If the bandwidth occupied by the above services is different, the other services By classifying and allocating a separate mLLID, deriving the required bandwidth for the service at the time of channel allocation, and then allocating the required amount of bandwidth, we aim to reduce bandwidth loss.

Below, we will explain this multicast processing process in detail.

Figure 2 is a flowchart showing an OLT multicast processing method in a passive optical network according to an embodiment of the invention. As shown in Figure 2, the multicast processing flow is as follows.

0) First, when the ONU/ONT 20 is registered with the multicast processing unit 100 of the OLT 10 and connected to each other online, the mLLID for the aggregate session is registered with the ONU/ONT 20. is registered in

1) Next, the subscriber (STB) 30 connected to the ONU/ONT 20 sends an IGMP (source, group) JOIN packet to the ONU/ONT 20.

2) Next, the ONU/ONT 20 records the source MAC (Media Access Control) address of the received IGMP packet and registers the receiving port in its internal MAC table.

3) Next, the multicast processing device 100 of the OLT 10 receives the IGMP (source, group) JOIN packet through the unicast LLID.

4) And if the joined group belongs to a single-session, the single-session mLLID is registered in the ONU/ONT (20).

5) Next, the multicast processing device 100 of the OLT 10 sends a dynamic multicast control (mLLID, (source, group), client MAC) OAM (Operation, Administration and Management) message to the ONU/ONT. and the ONU/ONT (20) records this information in the internal MAC table.

6) Next, the group membership is recorded in the multicast processing unit 100 of the OLT 10, and the multicast processing unit 100 forwards the traffic of the joined channel to the ONU/ONT 20.

7) Next, the multicast processing device 100 of the OLT 10 sends an IGMP (source, group) JOIN packet to the upper network.

8) Next, the multicast processing device 100 of the OLT 10 records the IGMP JOIN information received from the L2 multicast forwarding table through an IGMP snooping operation.

9) Next, the multicast processing device 100 of the OLT 10 receives traffic from the upper level device, and then adds (source, group) to the traffic received in the L3 multicast forwarding table in the multicast routing table. Check if there is

10) Next, the OLT 10 adds the tunnel ID to the multicast traffic through the line card of the multicast processing device 100 and sends it to the line card so that the traffic can be successfully forwarded with the mLLID. do. The ONU/ONT 20 checks whether the received multicast traffic matches information stored in the multicast forwarding table. If a match is found in the table, traffic is forwarded to the port that learned the client MAC address from the table.

Below, a device for such multicast processing will be described.

Figure 3 is a block diagram showing the configuration of an OLT multicast processing device in a passive optical network according to an embodiment of the present invention.

As shown in FIG. 3, the multicast processing device 100 for each service according to the present invention includes a control module 110 and a PON interface module 120.

Here, the control module 110 again includes a multicast processing unit 111 for each service, a network service unit 112, and a switch unit 113.

Additionally, the PON interface module 120 includes an IGMP processing unit 121, a message handler 122, and a PON interface unit 123.

The IGMP processing unit 121 is a single control point for IP multicast operation. This reduces the need for IGMP in the ONU 20. From the multicast client's perspective, the OLT 10 operates as a device that performs IGMP queries and operates as an IPv4/IPv6 multicast router. That is, the OLT 10 must provide IP multicast query and routing.

When a multicast client wants to start or stop receiving an IP multicast session, it sends an IGMP membership report. The ONU (20) transparently passes the membership report to the OLT (10).

Additionally, forwarding of the IGMP packet follows the following requirements.

1) The OLT (10) must forward all downstream IGMP messages sent to all host addresses and all node addresses using the mLLID for the multicast control traffic of each IP service group.

2) The OLT 10 must forward all downstream IGMP messages sent to the group-specific address through the interface using the mLLID for the IP multicast session. This is an mLLID allocated by the OLT 10 for forwarding multicast data to an address for a specific group.

3) The ONU 20 must bridge all upstream IGMP messages using the upstream unicast LLID corresponding to the interface on which the ONU 20 received the packet. When the OLT 10 first receives an IGMP join request (membership report) message from a multicast client, the OLT 10 must verify whether the client is authorized to receive an IP multicast session. If the subscriber's terminal is authorized for the session and is not currently configured in the ONU 20, the OLT 10 must add the mLLID and configure filtering and forwarding parameters related thereto. If the subscriber terminal is not authorized in the ONU 20, the OLT 10 should not add mLLID and configure filtering and forwarding parameters related thereto.

4) When the OLT 10 determines that there are no multicast clients for a dynamic IP multicast session in the ONU 20, the OLT 10 must delete the mLLID and set related filtering and forwarding parameters. When the OLT 10 determines that there are no multicast clients for an IP multicast session on the ONU 20, the OLT 10 may choose to release the mLLID and reuse it as needed.

The configurations 114 and 124 can be saved in the form of a file or table, and settings for the configuration include the following.

1) Set the multicast service profile (downstream service class, group QoS-config, Group-Config). It manages the multicast session scope and service class for each channel.

2) Next, set multicast enable/disable. This is to manage multicast enable configuration.

3) Set the bandwidth of multicast admission control. It manages the configuration for multicast admission control.

4) (Source, group) Set multicast route information. This is used to process IGMP. OLT 10 receives information from a multicast routing database.

When multicast is configured, IGMP packet traps and IPMC (IP Multicast Control) forwarding rules are set for each subscriber terminal.

Additionally, when a multicast service profile is set, the profile is created and the QoS value of the service class is stored. Additionally, the maximum number of multicast entries per subscriber terminal is set. For example, the maximum number of multicast entries can be set to 64. Also, for single session management, set the bandwidth for multicast admission control. Set group configuration (GC) for each interface.

Session limits for aggregate-session are used to limit the number of allowable channels. The number of channels is also limited by a command specifying the maximum number of multicast entries.

The network service unit 112 sends an IGMP JOIN packet to a higher-level device in order to receive traffic of the joined channel, receives traffic from the higher-level device, and then sends the traffic received to the L3 multicast forwarding table (source , group) is in the multicast routing table. And for multicast traffic through the line card, the tunnel ID is added to the multicast traffic and sent to the line card so that the traffic can be successfully forwarded with the mLLID. The ONU/ONT 20 checks whether the received multicast traffic matches information stored in the multicast forwarding table. If a match is found in the table, traffic is forwarded to the port that learned the client MAC address from the table.

The multicast control unit 111 for each service manages and processes multicast LLIDs for collective sessions and single sessions. Multicast LLID refers to the logical link of EPON that will forward multicast traffic. Here, the methods of group sessions and single sessions are used.

In the case of an aggregate session, multiple channels are forwarded by one multicast LLID (broadcast domain). Traffic from channels that do not match the multicast service profile is forwarded through the broadcast domain.

Channels forwarded according to collective sessions are managed and limited by setting session limits. For example, the default number of channels is 250. Session limits apply per PON port. For collective sessions, the EIR/CIR bandwidth is determined according to the user's settings, and the sum of EIR/CIR and the allowed number of session limits are determined. Here, EIR/CIR is used to ensure reliable end-to-end QoS. Traffic that always requires guarantee, such as voice or video, is guaranteed by classifying it with CIR (Committed Information Rate), and traffic that does not mind delay, such as Internet and data, is guaranteed. It is guaranteed by classification by EIR (Excess Information Rate).

The aggregate session refers to the MQOS_DEFAULT service-class, and if the EIR of each channel is 20 and the CIR is 5M, the bandwidth is calculated as follows.

EIR = 5 Giga (20M x 250 channels)

CIR = 1.250 Giga (5M x 250 channels)

For a single session, one channel is forwarded by one multicast LLID. Each channel must belong to a multicast service profile. Simply put, a multicast LLID is assigned for each channel. The session-limits for a single session are as follows:

Admission control allows session-limits for a single session to be set per PON port. The sum of EIRs for a single session cannot exceed the bandwidth of the specified admission control. If the total value of the EIR exceeds the specified bandwidth, the IGMP join for the new channel is dropped to ensure the traffic bandwidth of the joined channel.

Multicast LLID is created in the following order. 1) Create a multicast LLID for a single session on the PON line card. 2) Next, the multicast control unit manages these LLIDs, supports multicast features, and supports traffic control. 3) Next, generate as many multicast LLIDs as necessary each time initialization occurs. In this way, multicast LLIDs can be effectively combined on each channel.

The relationship between LLID and unicast LLID and multicast LLID is as follows. The number of LLIDs is provided on the line card up to 2000. The default number of LLIDs for a single session is 512. If 2k LLIDs are exhausted, the line card cannot combine unicast LLIDs for unicast traffic forwarding. This is why the default number of multicast LLIDs for a single session is limited.

If a broadcast LLID is used as a multicast LLID for an aggregate session, the line card equally assigns all unicast LLIDs in the broadcast domain to each ONU and forwards the traffic. Since this method cannot guarantee bandwidth for services allocated to a specific unicast LLID, this method should not be used. Therefore, a separate LLID needs to be created on the line card and needs to be used as a multicast LLID for the collective session.

The IP multicast model of the present invention supports IP multicast for high-speed data (HSD) IP services. This model supports delivery of all-source multicast and source-specific IP multicast streams to the ONU, and the ONU supports IP multicast. Not aware of the multicast control protocol, the ONU does not perform a proxy or snoop to track L3 IP multicast group membership. Instead, all processing and management functions related to multicast group membership are performed by the OLT.

The passive optical network of the present invention supports forwarding all source multicast traffic for IGMP and supports QoS for downstream multicast. Additionally, the passive optical network supports static multicast and downstream encrypted multicast. The passive optical network also supports support for IPv4 and IPv6 multicast traffic and explicit tracking in the OLT of CPEs joined to a given multicast group.

The OLT system according to the present invention must comply with the following specifications to apply multicast downstream QoS.

QoS support is available for sessions dynamically joined using a multicast management protocol such as IGMP, as well as sessions statically joined using static multicast session encoding. For downstream IP multicast traffic, QoS is supported using the concept of group service flows. Like classifier matches and unicast traffic forwarding on service flows, group classifier rules match multicast traffic and forward that traffic in group service flows.

For IP multicast QoS, the operator configures entries in the group configuration and group QoS configuration tables to control the creation of group delimiter rules and group service flows on each downstream channel. These tables only configure QoS for IP multicast sessions and do not control how the OLT system replicates IP multicast traffic to multicast LLIDs. Replication of IP multicast traffic is determined based on the participants for the IP multicast session. Multicast replication is performed per downstream channel configured within the MAC domain, whereas in a subscriber network, multicast replication is performed per downstream channel within the MAC domain.

The operator uses the group identifier and entries in the group QoS configuration table to define the QoS required for various IP multicast sessions. When the first client behind the ONU sends a multicast IGMP join request upward, the OLT system uses the group identifier and the information in the group QoS configuration table to dynamically apply group identifier rules and group service flows to the appropriate downstream channels. must be created. The OLT system follows the procedures defined below to control QoS for multicast sessions.

Each group QoS configuration item has QoS control parameters necessary to determine how the OLT system initiates group service flows.

When the QoS control parameter has a value for a single session, the OLT creates a group service flow for each session that is each unique combination of (source, group) IP addresses matching the group configuration items.

If the QoS control parameter has the value of aggregate session, the OLT creates only one group service flow and associates a group delimiter rule item with the group service flow as necessary.

In single session, there is only one multicast session per group service flow. On the other hand, in an aggregate session, multiple multicast sessions use the same group service flow.

The OLT must associate each group service flow with a unique multicast LLID (mLLID), each time creating a new group service flow. This mLLID is signaled along with multicast filtering and forwarding information to the ONU required to receive and forward multicast traffic.

The OLT must set a default group service flow, and all undifferentiated multicast traffic is forwarded according to the default group service flow. The OLT associates a default group service flow with a unique multicast LLID (mLLID). This mLLID is signaled to ONUs that need to receive and forward multicast traffic being sent according to the default group service flow.

The PON interface unit 123 performs multicast forwarding, and the passive optical network supports IP multicast for high-speed data services by adopting an IP multicast model. The ONU does not proxy or snoop messages to track L3 IP multicast group membership. And there is no awareness of IP multicast control protocol. The ONU forwards the IGMP control message received from the client CPE to the OLT as is.

Support of the IP multicast control protocol and tracking of L3 IP multicast group membership are centralized and performed in the OLT. The OLT forwards all downstream packets to a specific multicast session from the multicast set on the multicast LLID assigned by the OLT. From an OLT perspective, mLLID identifies a given multicast session to be received by a set of ONUs. The mLLID is used by the ONU to filter and forward multicast packets.

Additionally, the OLT controls multicast forwarding of downstream multicast packets to a specific interface through the configuration of the ONU. The OLT configures the ONU with a group forwarding attribute associated with mLLID to specify forwarding of IP multicast packets.

The method for allocating multicast traffic in a single session is as follows. First, an IGMP report is performed, and the IGMP report includes (source, group) information. Next, update the (source, group) traffic. IGMP reports are used for all source multicast processing. Since it only contains (*, group) information, the update information of the (source, group) channel is given in the multicast processing module for channel allocation.

For every source multicast, the (source, group) information is updated and then the traffic is forwarded. If multiple subscribers connected to the same port monitor the same channel, the multicast LLID to which the channel is forwarded must be shared.

Figure 4 is a flowchart showing a procedure for forwarding multicast traffic according to an embodiment of the present invention.

As shown in FIG. 4, the procedure for forwarding multicast traffic is to first connect online with the OLT 10 through a connection request (S110) from the ONU/ONT 20 to the OLT 10, and then When an IGMP JION request is received from the connected ONU/ONT 20, the multicast processing device 100 decodes the received IGMP (S120).

Next, the multicast processing device 100 uses the decoding result to determine whether the request is a request for a collective session or a single session (S130).

Meanwhile, the multicast processing device 100 decodes the received IGMP and determines whether the request is an aggregate session or a single session based on the destination address (e.g., IP address or MAC address) included in the IGMP. Determine whether or not

That is, the multicast processing device 100 determines that the request is an aggregate session when there are multiple destination addresses included in the received IGMP or when at least two IGMP join requests with the same destination address are received, When the IGMP join request is received one by one, it is checked whether the same service is being provided to the corresponding ONU/ONT, and if the same service is already provided, it is judged as a collective session. If the same service is not provided, it is judged as a single session. judge.

On the other hand, when there is only one destination address included in the IGMP received one by one, providing service traffic by creating a channel in a separate single session without checking whether the same service is provided means that the bandwidth for channel allocation is limited. As the number of IGMP join requests increases, there is a problem that efficient bandwidth management and use cannot be achieved.

Accordingly, in the present invention, limited bandwidth can be efficiently managed and used by determining whether the request is an aggregate session based on the received IGMP.

Next, if the determination result is an aggregation session (S120), the multicast processing device 100 transmits the mLLID for the aggregation session to the ONU/ONT 20 to enable registration (S131).

Next, as a result of the determination, if the request is a request for a single session, the multicast processing device 100 performs a group membership lookup, a multicast profile lookup, and a multicast profile lookup for the IGMP join request, and It is checked whether the total EIR value of the channel for the session is outside the range configured in the admission control maximum maintenance bandwidth, and if channel allocation is possible as a result of the check, source and group IP addresses and CPE are generated from the IGMP ( S140).

Next, the multicast processing device 100 transmits a single session mLLID to the ONU for registration (S150), and sends a dynamic IP multicast control (mLLID, (source, group), client MAC OAM message to the ONU /Transmitted to the ONT (20), so that the ONT/ONU (20) can add the received message to the internal MAC table (S160).

At this time, the multicast processing device 100 registers the IGMP (source, group) information in the OLT 10, updates the IGMP join and the membership, and transmits the IGMP join packet to the upper network.

Next, when traffic for the transmitted IGMP join packet is received from a higher-level device, the multicast processing device 100 allows the traffic to be forwarded to the corresponding ONU/ONT 20 with the corresponding mLLID ( S170).

Meanwhile, the ONU/ONT 20 checks whether the received traffic matches information stored in the multicast forwarding table and forwards the traffic to the port for which the client MAC address has been learned from the table.

Meanwhile, as a result of determination in step S130, if the IGMP join request is an aggregate session (S130), the multicast processing device 100 transmits the aggregate session mLLID to the ONU/ONT 20 to enable registration ( S131).

Next, the multicast processing device 100 performs a group membership lookup, a multicast profile lookup, a global session limit check, a check of the number of groups that can be created in the CPE, and (*, group) and (group, source) IP addresses. Creation and CPE creation are performed (S141). At this time, the service-specific multicast processing device 100 updates the (source, group) corresponding to the IGMP in the ONT/ONU 20 and starts a join timer (S141).

Meanwhile, through the global session limit check, if the number of channels allowable for the corresponding join request is exceeded, the multicast processing device 100 drops the corresponding IGMP join request. At this time, in preparation for the ONU/ONT 20 waiting indefinitely, the multicast processing device 100 notifies that channel allocation cannot be performed for the IGMP join request for more than a certain period of time according to the join timer.

Next, the multicast control device 100 transmits a dynamic IP multicast control (mLLID, (source, group), client MAC OAM message to the ONU/ONT 20, so that the ONT/ONT 20 Allows the received message to be added to the internal MAC table, registers the IGMP (source, group) information in the OLT 10, updates the IGMP join and the membership, and sends the IGMP join packet to the upper network. transmit (S151).

Next, when traffic for the transmitted IGMP join packet is received from a higher-level device, the multicast processing device 100 allows the traffic to be forwarded to the corresponding ONU/ONT 20 with the corresponding aggregate session mLLID. Do (S170).

As described above, the present invention is a passive optical network (PON) in which the OLT connects the ONT/ONU to a single-session, aggregate-session, or combination thereof according to the IGMP message received from each ONU/ONT. When forwarding multicast traffic in a mode that includes a combination, channel allocation is performed for each service using multicast LLID (Multicast LLID: mLLID), and the configuration settings can be changed in real time, thereby limiting overall bandwidth in real time. I want to control it. In reality, the types and bandwidth of services that must be delivered through the optical subscriber network are very diverse, and the configuration of the service desired by the subscriber is variable each time, so the configuration is dynamically set for each service and applied in real time, such as CATV, VoD (SD, In delivering a wide variety of multimedia services such as HD, UHD, Internet broadcasting (IPTV), and data broadcasting through a subscriber network, there is an advantage in efficiently utilizing bandwidth.

In the above, the preferred embodiments according to the present invention have been described in detail, but the technical idea of the present invention is not limited thereto, and each component of the present invention is changed or modified within the technical scope of the present invention to achieve the same purpose and effect. It could be.

10 : OLT 20 : ONU/ONT
30: Subscriber 40: Service network
100: multicast processing device 110: control module
120: PON interface module 111: Multicast processing unit for each service
112: Network service unit 113: Switch unit
121: IGMP processing unit 122: Message handler
123: PON interface unit 124: Configuration table (file)

Claims (12)

Receiving an IGMP join request from an ONU/ONT that has received an IGMP join request from a subscriber terminal (CPE);
Processing the received IGMP join request; and
Allocating a multicast LLID (mLLID) to each service according to the processed IGMP, and performing channel allocation for each service classified by the multicast LLID (mLLID),
Depending on the mode including whether it is an aggregate session, a single session, or a combination thereof, the overall session limit is checked in the case of the aggregate session, and in the case of the single session, the overall EIR value of the channel is the range of bandwidth allocated for multicast admission control. A multicast processing method for each service in a passive optical network, comprising checking whether it is within the range of the session limit and the bandwidth, and performing a service for each session if it does not exceed the range of the session limit and the bandwidth. In claim 1,
It further includes registering mLLID in the ONU/ONT,
In the case of the collective session, register the mLLID in the ONU/ONT in advance before the IGMP join request is received,
In the case of the single session, a multicast processing method for each service in a passive optical network, characterized in that the mLLID is registered in the ONU/ONT after the IGMP join request is received. In claim 1,
registering mLLID in the ONU/ONT when the ONU/ONT is connected to the OLT; and
A multicast processing method for each service in a passive optical network, further comprising determining whether it is an aggregate session or a single session from the processed IGMP join request. In claim 1,
The multicast processing method for each service is:
For the IGMP join request, performing IGMP decoding, group membership lookup, and multicast profile lookup;
generating source and group IP addresses from the IGMP; and
Forwarding multicast traffic to the source and group IP addresses. A multicast processing method for each service in a passive optical network, further comprising: In claim 1,
The step of performing the channel allocation is,
A multicast processing method for each service in a passive optical network, further comprising performing dynamic IP multicast control with an ONU/ONT by adding an OAM message including the mLLID, source and group IP addresses, and client MAC address. . In claim 1,
The step of performing the channel allocation is,
A multicast processing method for each service in a passive optical network, further comprising classifying the service as a different service and assigning an mLLID if the bandwidth occupied by the service is different even if the subscribers or channels are the same. an IGMP processing unit that receives an IGMP join request from an ONU/ONT that has received an IGMP join request from a subscriber terminal (CPE) and processes the received IGMP join request; and
It includes a multicast processing unit that allocates a multicast LLID (mLLID) to each service according to the processed IGMP and performs channel allocation for each service classified by the multicast LLID (mLLID),
Depending on the mode including whether it is an aggregate session, a single session, or a combination thereof, the overall session limit is checked in the case of the aggregate session, and in the case of the single session, the overall EIR value of the channel is the range of the bandwidth allocated for multicast admission control. A multicast processing device for each service in a passive optical network, comprising performing a service for each session if it is within the session limit and the bandwidth. In claim 7,
The IGMP processing unit,
further comprising registering the mLLID with the ONU/ONT,
The multicast processing unit,
In the case of the collective session, register the mLLID in the ONU/ONT in advance before the IGMP join request is received,
In the case of the single session, a multicast processing device for each service in a passive optical network, characterized in that the mLLID is registered in the ONU/ONT after the IGMP join request is received. In claim 7,
The IGMP processing unit,
It further includes the role of registering the mLLID in the ONU/ONT when the ONU/ONT is connected to the OLT;
The multicast processing unit,
A multicast processing device for each service in a passive optical network, further comprising determining whether it is an aggregate session or a single session from the processed IGMP join request. In claim 7,
The IGMP processing unit,
For the IGMP join request, further comprising performing IGMP decoding, group membership lookup, and multicast profile lookup,
The multicast processing unit,
A multicast processing device for each service in a passive optical network, further comprising generating source and group IP addresses from the IGMP and forwarding multicast traffic to the source and group IP addresses. In claim 10,
The multicast processing unit,
A multicast processing device for each service in a passive optical network, further comprising performing dynamic IP multicast control with an ONU/ONT by adding an OAM message including the mLLID, source and group IP addresses, and client MAC address. . In claim 7,
The multicast processing unit,
A multicast processing device for each service in a passive optical network, further comprising classifying the service as a different service and assigning an mLLID if the bandwidth occupied by the service is different even if the subscribers or channels are the same.