Key components of the NGN network

Softswitch:It is also called a media gateway controller. It is responsible for call control, that is, establishing, monitoring, and removing call connections. Its functions are equivalent to those of the call processing module of the original circuit switch. Softswitch is only responsible for signaling and call control, and has no transmission function. That is to say, two users communicate with Softswitch only when a call is established or disconnected through a signaling or protocol, in other cases, voice, video, or other media streams between two users are not subject to SoftSwitch.
Access device:Including access to media gateways and IAD integrated access devices. Its function is to achieve access to end users, just like the user boards in traditional switches. However, because NGN is deployed on the group network, the access device of NGN is a little more complex than the user board in the switch: in addition to the original modulus conversion function, the format conversion between a general digital signal and a packet that can be sent on the group network must also be completed. In addition, it must also be able to convert some basic call signals processed by the original user board, such as detaching, dialing, and hanging up) into the protocols that can be transmitted on the network, in this way, the interaction between the access device and the softswitch is realized. In this way, Softswitch can receive and process the information sent from the access device, control the access device, and establish a call connection.
Packet transmission network: in NGN, packet transmission network is crucial. All information of the entire NGN network, including the transmission and forwarding of signaling streams and media streams, depends on the unified packet transmission network. It covers the Switching Network Board, signaling network board and transmission network in the original PSTN network.
NGN uses a group network to achieve unified information bearer. Its purpose is to achieve multi-service convergence on a unified basic network. According to the development trend of the current sub-network, the IP-based network has become a de facto standard. Therefore, the IP-based bearer network of NGN is also recognized by the industry. The flexibility and openness of IP addresses bring many benefits to the Development of NGN, but they also bring many problems, such as QoS, security, management, and insufficient IP address space. However, the current development of the transmission network technology has become a key factor restricting or promoting the development and maturity of NGN.
Relay gateway and signaling gateway: In a pure NGN network, it can be said that the relay gateway and signaling gateway do not exist. However, because NGN cannot replace PSTN overnight, that is, during the construction of NGN, there will be a very long period of time, which requires the coexistence of NGN and PSTN. The coexistence of networks requires intercommunication. The relay gateway and the signaling gateway are the devices for intercommunication between NGN and PSTN. The so-called relay gateway is to complete the conversion of the 64 K link of the circuit relay based on PCM code) and the media stream on the group network. The so-called signaling gateway, it is to complete the conversion of the SIGTRAN Signaling System Based on circuit relay's no. 7 signaling system and based on the packet network IP bearer.
Media Resource Server:A circuit switch has a dedicated component to complete the so-called sound-releasing and Sn-receiving functions and implement some special services, for example, we often hear that "the user you are calling is busy ......". In the NGN system, all the components in the vswitch are taken out to form a public and independent component called a Media Resource server. It can provide media resources based on IP networks for NGN networks.
Compared with the sound receiving box in a vswitch, NGN's Media Resource server is more powerful and scalable. It not only provides basic Sound Receiving functions, it can also provide video resources and multimedia conference resources to implement text-to-speech conversion and speech recognition functions, and provide support for many special services of NGN.
Service server: In the NGN network, the location and function of the Service Server are similar to that of the intelligent network in the traditional telecom network. Its role is to provide value-added services for users in the NGN network. Currently, this type of value-added services directly provided by the NGN Value-added Service Server includes: SIP pre-payment, WEB800, CTDCLICKTODIAL click dialing), CTFCLICKTOFAX click fax), umuniiedmessaging unified message), and IMINSTANTMESSAGING instant message) ......
To provide value-added services of NGN, an important idea is to open third-party business interfaces. Through this interface, value-added business development by a third party can be realized, making personalized business customization possible. The current standard for this interface is PARLAY. PARLAY itself is not an abbreviation and is a special word. The original intention is similar to the meaning of "adding on the casino". It is used here to indicate the meaning of "adding value. The basic concept of PARLAY is to block the details in the NGN network through encapsulation technology, abstract them into various capability sets, and then provide them to third parties through the standard APIAPPLICATIONINTERFACE application interface, this allows a third party to develop services without having to worry about the specific device and manufacturer details of the basic network, as long as the corresponding API is called. This third-party service development interface is considered to be the most attractive capability of NGN and can completely solve the problem of insufficient capability of traditional network services.