Transmitter and method of asynchronous transmitting mode data flow

Abstract

The method includes following steps: after DSLA receives data flow, ATM cell builds up Ethernet frame that is made retransmission process according to coincidence relation of ID information of Ethernet frame with multicast packet and multicast VC or subscriber VC ID; the Ethernet frame are converted into ATM cell and is transmitted to the exchange channel of ATM; then it is transmitted to network or user terminal equipment. The invention puts multi multicast packet data into one VC so that the up stream link resources and equipment invest are saved.

Description

technical field [0001] The present invention relates to a device and method for forwarding multicast data streams in high-speed Internet access and dedicated line services, in particular to an Asynchronous Transfer Mode Digital Subscriber Line Access Multiplexer (ATM DSLAM for short). A method and device for efficiently forwarding multicast data streams. It belongs to the field of communication technology. Background technique [0002] At present, the main applications of Asymmetrical Digital Subscriber Loop (ADSL) access are still high-speed Internet access and private line services. With the emergence of multi-point communication services such as network video, distance education, and real-time stock information transmission, ADSL broadband Access to provide multicast services has become an inevitable trend. [0003] Multicast technology realizes efficient point-to-multipoint data transmission in the network. After adopting multicast technology, the source server and the...

AI Technical Summary

Problems solved by technology

[0008] 1. The multicast source is identified by the virtual channel identifier / virtual channel identifier (VPI / VCI) connected to the multicast source, and it is not possible to implement a VC connection to carry multiple multicast groups

The multicast forwarding table needs to use the connected VPI / VCI to identify different multicast sources. Each multicast source must be used as an ATM node. On the one hand, it causes waste of connection resources and equipment, and reduces the flexibility and simplicity of networking. On the other hand, adding a new multicast source requires additional data configuration, and the scalability of the network is relatively poor.

[0009] 2. Multicast flow and unicast service flow need to be downlinked to DSLAM through different VCs

The processing of unicast flow and multicast flow in DSLAM is different, unicast flow only performs simple cross-connection on DSLAM; while multicast flow needs to be multicast forwarded according to VPI / VCI identification, resulting in unicast flow and multicast flow Streaming downstream cannot use the same VC

[0010] 3. ATM DSLAM implements multicast replication through point-to-multipoint connection, which is not efficient; multicast data replication is performed inside DSLAM, which increases the load of DSLAM equipment. When there are too many multicast data, it is easy to become a performance bottleneck

[0011] 4. The user RTU needs to be configured with at least two VCs, which makes terminal configuration more complicated

However, in order to prevent out-of-sequence cells from the DSLAM downlink to the RTU, unicast data and multicast data need to be carried on two VCs separately, which brings certain complexity to the configuration of the RTU.

[0012] 5. Fixed forwarding according to the multicast forwarding table, users cannot dynamically join or leave a multicast group

Moreover, since the multicast forwarding table is managed and configured by the network administrator, the business is inflexible, the maintenance workload is increased, and the user's bandwidth is occupied when the user does not need it.

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