Explanation of media logical channels in Softswitch Technology

The Softswitch technology is worth learning a lot. Here we mainly introduce the media logical channels in the Softswitch technology. This channel carries H.245 information, which is used for media control with capability exchange support. After the caller completes the capability exchange, he/she creates a media logical channel through this channel.

Media Logical Channel

This channel carries voice, video, and other media information. Each media type carries a one-to-one channel, and RTP and RTCP are used in each direction. H.323 requires that the RAS channel and media logic channel are carried on a very reliable transmission protocol, and the H.245 control channel is designated on the reliable transmission protocol, starting from the third version, it can be carried on unreliable transmission protocols.

Comparison between H.323 and SIP

SIP is proposed by the MMUSIC team of IETF. Compared with the H.323 protocol family proposed by ITU, SIP is simple, scalable, and scalable, and closely integrated with existing Internet applications. The two proposed a complete solution for the signaling of the IP phone system. They have the ability to establish, manage, and revoke call connections, and have the network management function, so that the endpoint users can establish and interact with QoS, and easy to expand new features, supports different types of interoperability. Of course, these two protocols both contain requirements on the decompression of Speech Encoding, but these are the same for the two Protocols.

Currently, H.323 and SIP are two major competing protocols in the group network. Among them, the H.323 protocol is the standard set by the ITU-T, And the SIP protocol is the standard set by the IETF, both of them can complete call establishment, release, service supplement, capability exchange, and other functions. The H.323 Protocol adopts the design concept of ISDN and uses the Q.931 protocol to establish and release a call, which is obviously characteristic of telecommunication network manageability and centralization. At present, the H.323 protocol has been widely used on the Internet. Compared with the SIP protocol, the H.323 protocol is more mature. Therefore, the IP address and telephone network of each operator in China currently use this protocol. The SIP protocol is simple, scalable, and closely integrated with existing Internet applications. Many people believe that the Protocol is easy to implement and has developed rapidly in the United States recently, at the same time, SIP will be widely used in the third-generation mobile communication core network and smart services. Supporting multiple protocols is one of the main features of the Softswitch technology, so the Softswitch technology can support both Protocols at the same time.

Conclusion

The Protocol Modification Process of H.323 indicates that network scalability is always a problem that cannot be ignored when constructing a VoIP network. With the construction of the broadband network, streaming media businesses become more and more important. The trend of gradually replacing the PSTN with the broadband grouping network is emerging, which provides a good platform for the development of VoIP. As one of the supporting protocols for the next generation network, the H.323 protocol will play an increasingly important role.

The second version of H.323 is very similar to the functions and services supported by the SIP. For supplementary services, H.323 is more strictly defined. Therefore, there are few interoperability problems in implementation. The two protocols can be compared with the call-based latency in their QoS support, and do not support resource reservation or CoSClass of Server settings ), however, the third version of H.323 will allow the signaling required by CoS. Therefore, the third version of H.323 is suitable for giant telecom carriers.

The Softswitch technology is only a method of implementation. It can be used in the IP Phone System Based on H.323 or in the SIP-based IP phone system. H.323 provides a centralized processing and management mode that matches the telecom network management mode. It has the ability to build an IP Phone System of any scale and is a good working mode.