Design of Intelligent Configuration and Maintenance Scheme for IPTV Set-top Box
The IPTV receiving terminal, also known as the IPTV set-top box, is one of the key equipment in the IPTV system. Its main functions include: supporting LAN or xDSL network transmission, receiving, and processing of IP data and video streams; Support video decoding such as H.264, MPEG-2, MPEG-4, WMV, and Real; Support corresponding CA technology; Support HTML webpage browsing and online games, etc.
Due to the limited hardware resources of set-top boxes, their operating systems generally use embedded operating systems such as WINCE, embedded Linux, RTOS, etc.
Due to the fact that IPTV is based on network transmission, as a network access device, set-top boxes should be set with network parameters such as IP addresses and gateways before use. If manual setting is used in actual engineering, it will greatly increase the operator's labor costs, and the maintenance costs in the future will also increase accordingly. Therefore, in the design of IPTV set-top boxes, consideration should be given to implementing plug and play functionality, that is, achieving automatic configuration.
Based on the above situation, this article designs a network solution that can manage and configure set-top boxes in a networked manner. This solution is based on the BOOTP (BOOT strapping Protocol) protocol in the TCP/IP protocol cluster, and utilizes a network server to automatically configure the network parameters of the set-top box. The entire process does not require user intervention, truly achieving plug and play functionality; In conjunction with a universal set-top box design, it can also achieve automatic upgrading of set-top box video decoding and other programs; Monitoring and maintenance of user set-top boxes only need to be carried out on remote servers.
Overall scheme design
Management Mode Selection and Design
One of the advantages of the client server model is its great flexibility. After adopting the client server mode, the setting of network nodes can be achieved through setting up the server side, which can adapt to the needs of nodes in different types and environments. In order to complete the networked automatic configuration of the set-top box, a startup configuration server is set up on the underlying network of IPTV. After the set-top box is powered on and self tested, it is logged in to the startup configuration server through a login program fixed in the ROM to complete the relevant parameter configuration. After obtaining the relevant settings from the server, it starts working.
Server type and protocol selection
This solution uses a BOOTP server and its protocol for management and configuration. BOOTP and RARP (Reverse Address Resolution Protocol) are two protocols in the TCP/IP protocol cluster, both implemented in a client server mode and capable of networked management and configuration of on-site device IP addresses. However, compared to RARP, BOOTP mainly has the following advantages: (1) it can obtain all the information required for node startup, which is much more powerful than RARP. (2) Based on the transmission protocol UDP, it is easy to implement and has good portability without directly dealing with hardware. (3) BOOTP servers exist as an application, which is different from the way RARP servers exist in the kernel. The advantage is that they are easy to modify and port, while RARP kernel servers are difficult to modify and port. (4) The protocol has high transmission efficiency and a large amount of exchanged information, which can fully utilize hardware capabilities. (5) RARP only exchanges one IP address at a time, while BOOTP messages not only exchange IP addresses, but also provide gateway IP, server host name, and 128 byte startup file name.
Based on the above analysis, BOOTP is chosen to implement networked configuration management for set-top boxes.
BOOTP message format, transmission, and configuration process
BOOTP message format
BOOTP first appeared in Unix systems, responsible for remote startup of Unix terminals, and is still the most commonly used method in Unix and later Linux systems. The BOOTP protocol has two types of messages: BOOTP request and BOOTP response. To simplify the implementation of BOOTP as much as possible, each domain of the BOOTP message is a fixed length domain, and the two message formats are identical.
BOOTP configuration process
(1) The BOOTP startup code in the ROM chip starts the client (at this point, the client does not have an IP address), and it sends a query request to the network in the form of a broadcast with an IP address of 0.0.0.0, which includes the MAC address of the client's network card. (2) The BOOTP server receives the request frame and searches for this MAC record in BOOTPTAB based on the MAC address in the frame, and sends information (such as client IP, server address, gateway IP, and startup file name) back to the client in a FOUND format. (3) The client reads the information in FOUND, then downloads the required startup configuration file through the TFTP (Trial File Transfer Protocol) server, and simulates this file as a disk in the workstation memory, starting from this simulated disk.
Implementation of a BOOTP based set-top box management solution
Server Configuration
(1) Set up a BOOTP server on the underlying IPTV network (community network). BOOTP supports multiple servers working simultaneously and can be designated by customers as the servers they serve (by filling in the server IP address in the BOOTP request). If there are many set-top boxes in the network of a certain community, multiple servers can be set up to increase the reliability of the network.
(2) Configuration of the BOOTPTAB table. Create a table of terminal device MAC addresses, IP addresses, and corresponding startup configuration files in the BOOTPTAB table. The future maintenance of the set-top box IP address can be done in the BOOTP table.
(3) The startup configuration file is downloaded by TFTP. TFTP is a simplified file transfer protocol with the characteristics of being short and practical, which can be stored in ROM. It has low requirements for terminal devices and is easy to implement. Although FTP has powerful functions, its protocol is complex and requires high hardware requirements, making it difficult for set-top boxes to meet. Therefore, it is not practical for set-top boxes.
Implementation of automatic login for set-top box
Simply add the BOOTP startup code to the set-top box ROM to achieve automatic login from the set-top box to the server.
After introducing servers into the network management configuration of set-top boxes in this solution, although it will increase the cost of servers in the initial construction of IPTV networks, due to the network-based diskless startup of set-top boxes, there is no need to install startup configuration files, which can save set-top box hardware resources and reduce set-top box costs. Overall, the initial construction cost has not increased significantly.
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