This paper presents an efficient communication subsystem, DP-II, for clustering standard high-volume (SHV) servers using Gigabit Ethernet. The DP-II employs several lightweight messaging mechanisms to achieve low-latency and high-bandwidth communication. The test shows an 18.32 us single-trip latency and 72.8 MB/s bandwidth on a Gigabit Ethernet network for connecting two Dell PowerEdge 6300 Quad Xeon SMP servers running Linux. To improve the programmability of the DP-II communication subsystem, the development of DP-II was based on a concise yet powerful abstract communication model, Directed Point Model, which can be conveniently used to depict the inter-process communication pattern of a parallel task in the cluster environment. In addition, the API of DP-II preserves the syntax and semantics of traditional UNIX I/O operations, which make it easy to use.