Korea has been one of the early providers of the broadband Internet services in the world. Over 10 million subscribers use the internet data service using xDSL and AON. So far, xDSL system is considering the dominant access network transmission system. But from the 2005, TELCOS are more considering AON system at apartment area. They call Optical LAN. The brand name is very popular in Korea. KT has been provided Optical LAN service for apartment area. We call the name of Ntopia. We install L3 switch apartment main distribute frame (MDF) and FES in the each building. In general this service is target for new apartment area. But the AON system does not proper out of the CO. However, Passive Optical Network (PON) system has reliability in terms of OPEX comparing with AON. So I will introduce the Optical LAN using 100M WDM-PON.