NGN integrates network communication protocols to meet business needs

The goal of NGN is to build a group-based converged network that provides voice, data, multimedia, and other services, integrating communication, information, e-commerce, and entertainment. To achieve this goal, IETF and ITU-T have developed and improved a series of standard protocols: H.248/Megaco, SIP, BICC, SIGTRAN, H.323.
1. Protocol Classification
The NGN protocol includes non-peer and peer-to-peer protocols. The non-Peer protocol mainly refers to the Media Gateway Control Protocol H.248/Megaco. The peer protocols include SIP, H.323, and BICC. SIGTRAN is the signaling transfer protocol. Due to historical reasons, some of the NGN series protocols complement each other, while others compete with each other. H.248/Megaco is a non-peer master-slave protocol that works with other protocols to complete various NGN services. Both SIP and H.323 are peer-to-peer protocols, which have a competitive relationship. Because of their simplicity, versatility, and scalability, SIP has gradually become a mainstream protocol.
2. Protocol Application and Development
NGN is a converged network, including PSTN/ISDN, H.323, and ATM/IP. Network Interconnection is essential for the success of NGN. NGN networks mainly include Softswitch, media gateway, signaling gateway, smart terminals, and various databases/servers. SIP is a NGN multimedia communication protocol used for communication control and information interaction between Softswitch, SIP servers, and SIP terminals. The extended SIP-T enables SIP messages to carry ISUP signaling; media gateways can be set where media conversion is needed, H.248/Megaco is the media gateway controller (MGC) for controlling media gateways, the media conversion function is not responsible for call control. H.323 is also a multimedia communication protocol, which has a longer history than SIP, H.248, and Megaco. It is a complex protocol, the upgrade and scalability are not very good. SIP + H.248/Megaco can replace H.323. to interwork with the H.323 network, NGN must support this Protocol. SIGTRAN is used to solve the problem that the IP Network carries the No. 7 signaling, it allows signaling 7 to pass through the IP network to reach the destination; BICC allows ISUP protocol to be transmitted on different bearer networks (ATM, IP, PSTN.
3. Main protocols
3.1, H.248/Megaco
The H.248/Megaco Protocol is a product of the concept of gateway separation. The core of gateway separation is business and control separation, control and bearer separation. In this way, the business, control, and bearer can develop independently. While making full use of new technologies, operators can also provide a wide range of services to enhance network value through innovative services.
H.248/Megaco is a protocol developed based on the MGCP protocol (defined by RFC2705) and combined with the features of other media gateway control protocols. It provides a mechanism for establishing, modifying, and releasing control media, at the same time, it can carry some along-the-way call signals to support calls from traditional network terminals. This Protocol plays an important role in building an open and multi-network integrated NGN.
3.2. SIP protocol
Session Initiation Protocol (SIP) is one of the multimedia communication system framework protocols developed by IETF. It is a text-based Application Layer Control Protocol Independent of the underlying Protocol, it is used to establish, modify, and terminate multi-party or multi-party multimedia sessions on the IP network. The SIP protocol uses HTTP, SMTP, and other protocols to support proxy, redirection, user registration, and other functions. Supports user movement, and works with RTP/RTCP, SDP, RTSP, DNS, and other protocols. Supports Voice, Video, Data, Email, Presence, IM, Chat, and Game.
3.3 BICC Protocol
BICC protocol solves the problem of separation of Call Control and bearer control, so that call control signaling can be carried on various networks, including MTPSS7 network, ATM network, and IP network. BICC protocol evolved from ISUP and is an important supporting tool for the evolution of traditional telecom networks to integrated multi-service networks.
3.4. SIGTRAN Protocol
SIGTRAN is a working group of IETF. Its task is to establish a set of protocols for transmitting PSTN signaling over an IP network. The SIGTRAN protocol includes SCTP, M2UA, and M3UA, providing the same functions as SS7 MTP.
3.5. H.323 Protocol
H.323 is a set of standards that provide real-time audio, video, and data communication on the group network and is part of the series of protocols H.32x developed by the ITU-T to provide multimedia communication on a variety of networks.