The Design and Implementation of SIP Multi-domain SmartHome System

Heretofore, most of SmartHome systems deliver related services basing on a family local area network, and are not yet mature in remote control. In connection with this problem, we propose a SIP multi-domain system with distributed architecture, extend SIP protocol's redirect registration and call, make a combination of SmartHome system and the internet, and help people access to their home internal networking whenever and wherever. Introduction With the explosive growth of embedded electronics and automation equipment, Internet of Things (IoT) based on ad-hoc network is developing rapidly, and then provides people with all kinds of efficient and convenient application. As family ad-hoc network technology becomes more mature, such as zigbee, wifi, bluetooth, Ethernet and power line cable network technology, smart homes, being an important application field of IoT, also offers a variety of applications, such as visual intercom, home appliance control, intelligent lighting, etc. However, the intelligent network era of smart home is coming soon because of the rapid development of network technology in recent years, which developing to IP-centered multimedia business integrated network and presenting ubiquitous, fusion, open, integration [1]. This paper, based on the new features of smart home, using the SIP protocol, building SIP server and multiple domain management system, realize the home network and the Internet. SIP Protocol and its mobility SIP (Session Initiation Protocol) is a VOIP protocol made by IETF (Internet Engineering Task Force) to establish, modify and terminate multimedia sessions. It’s an important protocol of soft switching system and IMS (IP Multimedia Subsystem) in NGN (Next Generation Network) [2]. Similar to the HTTP protocol, SIP use the UTF-8 character set to encode, which is not only easier to read and understand, but also easy to extend [3]. In applications, it usually provides one basis to implement diffident function. A complex SIP system could have more than one SIP management area, which namely the SIP multi-domain systems, each region has its own independent domain name and SIP server to implement the management of inner domain user [2]. Because of the application of mobile communication network, it can be designed in the application layer to support the user terminal’s mobility based on SIP. The support for mobility of SIP implemented by registration mechanism, which register server constantly receive user registration information and update user current address stored in a location server [4]. User identifies current address by register process. With proxy server, redirect server and proper extension, SIP will support users and terminal mobility. The Overall Structure Design of SIP Multi-domain SmartHome System The Network Structure Design of System. As shown in Fig. 1, the SIP Multi-domain SmartHome System consists of two parts: Home External Networks based on Internet and Home Internal Networks based on Home Router. Home external network includes a home SIP server and 2nd International Conference on Electrical, Computer Engineering and Electronics (ICECEE 2015) © 2015. The authors Published by Atlantis Press 1194 some SIP local terminals (such as PC, embedded fixed terminal and wireless mobile terminal). Home internal network includes SIP Management Network, Application Service and SIP Remote Terminals. SIP Remote Terminals SIP Local Terminals Home Router Home External Networks Home Internal Networks Mobile Communication Network Application Services SIP Management Network Home SIP Server . SIP Remote Terminals Fig. 1 The Network Architecture of System Within each home internal network, it is necessary for a SIP server to manage the SIP terminals belonged to the same family group (user group), including the local terminals in the home internal network and the remote terminals in the home external network. After successful registration to the home SIP server, the SIP terminal is possible to communicate each other. With the home external network, there are some SIP register servers and database servers to build a SIP management network, which can manage the home SIP server. The remote terminals can inquiry the information of the home SIP server from the same home group, then realize the functions of Foreign Login and remote-control through the SIP management network. Moreover, Application server to provide value-added services can obtain the user resources by accessing to the database server of the SIP management network. The Design of SIP Management Network. SIP builds servers to manage network. To support the mobility of the terminal user and the remote access, the structure of servers can adopt distributed server model like domain name server tree. SIP multi-domain systems can be divided into multiple levels, and each level is divided into multiple domains. Server can manage other servers in lower level network domain under its jurisdiction, and provides relocation services to them and SIP terminals. SIP identifies and locates the SIP user terminal by URL (Uniform Resource Location) [5]. In SIP management network of this system, each server will be assigned a URL according to the domain name it affiliated. The format of URL is: username @ Multi-level domain name it affiliated. In view of the community character of smart home and the family application service, this system can be designed for 3 level domains, as Fig. 2 shows. Top level can be set to Cn domain according to provincial area. The URL format: Cn @ domain name n, Cn as provincial name, domain name n as DNS domain or public network IP of server. In the actual building process, Cn can be provincial domain or municipal domain according to the number of users. When the subordinate user scale is too large, we can also add sub-domain to build both provincial and municipal domains at the same time.