In this paper, we present source management routing algorithm (SMRA) providing a backup routing path for BGP. Each AS has a unique name, and chooses its virtual neighbors by name. Each AS only maintains one routing path to its virtual neighbors, and the ASes along a path to its virtual neighbors keep track of this path. SMRA provides routing paths between arbitrary pairs of ASes only based on the unique name. For this kind of name-based scheme, naming rule is of great importance. This paper makes a detailed analysis of the flat-name assignment policy for SMRA. We focus on two kinds of flat-name assignment policy: one is topology relative, and the other is topology irrelative. On the premise of awareness of network topology, flat-name assignment policy can improve SMRA routing performance.We ran a large number of experiments to explore what factors influence SMRA routing performance. Different flat-name assignment policies have a great impact on SMRA. We find virtual neighbor path length is not the longer the better through the analysis of flat-name assignment policy. Core node is another important factor impacting SMRA routing effectiveness. The result of experiment shows that the flat-name assignment policy that increases the number of virtual neighbor paths passed by core ASes can shorten average SMRA path length.