The current communications infrastructure at YerPhI has been developed beginning from 1994-1995 and mainly based on 10Mbps Ethernet technology. Later development 2001-2002 by using DESY supported old 10Mbps switches mainly concerned with sufficient enlargement, but actually information backbone itself and its topology remain unchanged. Last development was 2005- 2006 NATO Networking infrastructure project. In the framework of that project 4-wire Fiber optic cable are installed between 6 buildings of Yerphi. The new layer-II switches (one per building) were installed. User level network still manly based on 10 MB Hubs and hub-segmented huge network does not allow securely isolate one segment from other one and using VLANs. Even segmentation via routers does not solve the problem inside the segments themselves. For end users in YerPhI there used Intel based Workstations with Linux and Windows platforms. All computing facilities are included in YerPhl's Local Area Network. YerPhI LAN includes 10 buildings, covering big enough area. Practically all types of services with TCP/IP protocol stack are available for end users. In total YerPhI computer network consists of over 400 workstations. They are located in 10 buildings At Yerphi and Aragats ,Nor-Hamberd Stations (see Site Diagram).