7. Technological Overview 7.1 Network Structure and Technical Description Ethiopian Telecommunications Corporation, ETC has developed modern information and communications network infrastructure capable of supporting voice, data and video services, equitably across the country and with high capacity digital connectivity to the rest of the world. IP NGN Network is constructed in such a way that it can provide NGN (including GSM, Fixed NGN, CDMA, IP/Broadband Access Network services including Value Added Services) at regional cities, major cities, sub cities, and towns. The network is also available with the required capacity and distribution to bear all CDMA, GSM, IP/Broadband Access network services, VAS and the common future services. 17/02/2010 1

ETC-IP NGN bearer network adopts five layered topology; ▫Gateway layer/ deployed in 3 sites ▫Backbone layer/ deployed in 5 sites ▫Core layer/deployed in 17 sites ▫Edge layer/deployed in 25 sites, and ▫Access layer/ deployed in 84 sites (75 cities) Gateway layer is responsible for Internet connectivity to the outside world. Backbone layer is mainly responsible for service traffic forwarding and international traffic among the MAN. Core layer is mainly for convergence. Edge layer is used for aggregation of core switches. Access layer is where broadband access devices (MSAG and DSLAM) and ETC’s other networks (GSM, CDMA, FL-NGN) are connected 17/02/2010 2

3 Network Topology

Broadband Access – MSAG and DSLAM ADSL 2+ /Asymmetric Digital Subscriber line/ ▫ A modem technology that uses exiting twisted-pair telephone lines to transport high-band width data/ Max transmit distance is 6.5 KM. Max down rate is 24M. Max up rate is 1M. VDSL 2 /Very high data rate Digital Subscriber Line/ ▫ Transmit high speed data over short reaches twisted pair copper telephone lines, Max transmit distance is 2.5 KM. Max down rate is 85M. Max up rate is 50M. PON /Passive Optical Network / ▫Fiber-To-The-Home Solutions /FTTH/ ▫The main fiber runs on a PON network can operate at 155 Mbps, 622 Mbps, 1.25Gbps, or 2.5Gbps. ▫For EPON /Ethernet Passive Optical Network/ maximum transmission distance is 10 Km and data transfer rate is 1Gbps ▫For GPON /Gigabit Passive Optical Network/ maximum transmission distance is 20 Km and date transfer rate is 2.5Gbps 17/02/2010 4

IP Connectivity PPPoE/Point to Point Protocol over Ethernet ▫Support connections like dial-up users ▫User log in to the network using assigned user-id and password IPoE/Internet Protocol over Ethernet ▫IP users are always connected to a fixed physical port Internet – link to the global public network L3VPN – MPLS based WAN connectivity L2VPN – Ethernet circuit over WAN 17/02/2010 5

8.Assumptions