Linux-based Operating System And Software Design And Implementation Of E1 Interface

Router connects to the Internet as the hub, bearing almost all Internet routing packets forwarding. The security of routers has a significant impact on the security of information of our country, it is significant to design compeletely autonomous and controllable router to ensure the security of our country and people’s dalily life. Based on a collaborative project with a well-known domestic network equipment manufactures, we should develop domestic self-controlled routers for interconnecting private networks. The main research subjects of this thesis includes two aspects: one is to analyse the functional requirements of access routers, and explain the reason why we select Linux as the kernel of the router operating system, and achieve the operating system which is applied to the hardware platform of the equipment manufacture by software integration based on Linux kernel; the other is to design and realize the driver of the E1. Finally, we do a lot of device-level and system-level testing on the operating system and the E1 driver, varifing the correctness and practicality of the operating system and the E1 driver.This thesis based on Linux operating system, taking advantage of its open source nature, transforms Linux kernel into a router operating system. First of all, this thesis analyzes the basic functional requirements of that the enterprise routers should meet: routing and forwarding, software environment, system management requirement, network service requirement, protocol stack requirement, routing protocol requirement and security functional requirement. This thesis elaborates the reason why choosing Linux as the core of router operating system from three aspects: the open source nature, software advantages and protocol, focusing on the support of the Linux kernel to routing and forwarding. All the requirements fall into two categories: a part of them is supported by the Linux kernel itself, you need to configure the kernel before compiling the kernel, and select the appropriate option; the other requirements are not supported by the Linux kernel, you need search third-party software to meet the function. For the second class of requirements, it is better to do software adaption, selecting the best software by comparative analysis of all software that meet the needs. All the software filtered out should be integrated in the Linux kernel. After finishing the kernel matching and software integration, it’s time to test each function requirement verifying that all the needs are met. Finally, this thesis tests routing and forwarding performance of this router, including lantency,throughput and packet loss rate.In order to develop scenarios of the router, enabling it connects to wide area network, the router provides E1 interface. Another job of this thesis is to develop the driver of E1 interface on Linux operating system, making the router can input and output data using E1 interface. After the analysis of E1 driver demands, this thesis proposes E1 driver framework based on the hardware design, and divides E1 driver into two parts: control channel and data channel, elaborating design process of controlling channel and data channel. According to functional requirements and design architecture, this thesis achieves E1 driver from control channel and data channel, and points out some notable problems of the process of achieving. After the driver has been integrated into the operating system, the function requirement of E1 interface should be test.The operating system of the router and the driver for the E1 interface which is designed and implemented in this thesis have been applied to the access routers of the device manufacture, and put into commercial use.