Embedded systems are usually suffering from limited resources which require a modified architecture of software to take the best usage of the resources. TCP/IP is the most important communication protocol for networked embedded systems which provide internet connectivity for hosts. Many of TCP/IP development for embedded systems lack system modeling, analysis and design. This paper presents a proposed lightweight TCP/IP architecture which consists of TCP/IP kernel,memory management, multi-threading and socket support to fit limited hardware resources devices. SysML is a general purpose modeling language is used to model the lightweight TCP/IP. The proposed SysML model discusses full functional analysis, design and requirement of the proposed architecture.