【摘要】 大多数低端的嵌入式Internet系统因其处理能力或者程序空间的限制，往往只能提供基于以太网的TCP/IP协议栈及其支持的WWW等Internet服务。为了使这些嵌入式Internet系统能够接受远程拨号接入的控制并根据这些低端系统的实际需求，提出了一个嵌入式网关(WebitGateway)的设计和实现方法，用于提供嵌入式Internet环境下远程拨号接入协议PPP和以太网协议的转换。WebitGateway针对资源严重受限的嵌入式Internet环境，在满足功能和性能要求的前提下，简化了两个协议栈的实现，介绍了简化后的Modem驱动程序和网卡驱动程序及相关协议，还特别介绍了利用看门狗实现Modem安全可靠的故障恢复方法和利用复杂计算转移实现PPP协议中的安全认证协议CHAP的方法。更多还原

【Abstract】 Many embedded Internet systems have operated with limited memory and used processors with limited capacity, so they usually provide Internet services, such as WWW, supported by TCP/IP protocol stack based on Ethernet protocol. According to capacity of the low-cost systems, this paper presents a method of design and implementation of an embedded gateway WebitGateway, which can translate protocols between PPP protocol to Ethernet protocol. Using WebitGateways, these Embedded Internet systems can be accessed by remote dial-up users. The drivers and protocols needed by WebitGateway are simplified and showed in details. Specially, the failure recovery of Modem using watch-dog and shifting complex security computing from embedded gateway to remote host for CHAP are discussed in this paper.更多还原