Tsinghua University Tsinghua University Tsinghua University Zhongguancun Laboratory Huawei Huawei Intra-domain source address validation (SAV) plays an important role in defending against source address spoofing attacks in intra-domain networks. However, existing intra-domain SAV mechanisms have the problems of inaccurate validation, high operational overhead, and limited protection. To overcome these problems and improve intra- domain SAV, this document proposes an overall architecture of source address validation in intra-domain network (named as Intra-domain SAVNET). Intra-domain SAVNET discovers the real data-plane forwarding path via hop-by-hop message propagation and helps intra- domain routers generate accurate SAV tables.