Programmable networks[3](PNs) are a new type architecture of networks which allow users or the third part software providers to program it. The architecture of PNs can be customized by using open PNs interfaces(i. e. ,APIs of networks)and a set of services compositions and methods. The critical factors of the research of PNs are the requirement of rapid creation,develipment and management of new services. The new type architecture of networks can optimize the performance of networks ,accelerating the development and application of new technologies and protocols by distributing lots of computing tasks into the cheap node of networks. Opensig[2]v. s. active networks[1](ANs)are the two schools of PNs. This paper presents the concept ,model & critical technologies of PNs in detail,then provides the realization approaches of ANs.
