Issue link: https://www.e-digitaleditions.com/i/1081695
52 I ICT TODAY GPON Central Equipment Room Passive LAN (up to 20 km for a 32 split) OLT 2.5 Gb/s 1.2 Gb/s ONT Central Equipment Room GPON 2.5 Gb/s XGS PON 10 Gb/s OTDR TWDM PON 4x10 Gb/s 4x10 Gb/s 1.2 Gb/s 10 Gb/s ONT OLT CEx CEx = Coexistence Element (G.989.1) WM = Wavelength Multiplexer (G.989.1) WM OTDR Central Equipment Room GPON 2.5 Gb/s XGS PON 10 Gb/s 1.2 Gb/s 10 Gb/s ONT OLT CEx CEx = Coexistence Element (G.989.1) Add CEx Add XGS-PON ports Add/ Replace XGS-PON ONTs GPON Central Equipment Room Passive LAN (up to 20 km for a 32 split) OLT 2.5 Gb/s 1.2 Gb/s ONT Central Equipment Room GPON 2.5 Gb/s XGS PON 10 Gb/s OTDR TWDM PON 4x10 Gb/s 4x10 Gb/s 1.2 Gb/s 10 Gb/s ONT OLT CEx CEx = Coexistence Element (G.989.1) WM = Wavelength Multiplexer (G.989.1) WM OTDR Central Equipment Room GPON 2.5 Gb/s XGS PON 10 Gb/s 1.2 Gb/s 10 Gb/s ONT OLT CEx CEx = Coexistence Element (G.989.1) Add CEx Add XGS-PON ports Add/ Replace XGS-PON ONTs FIGURE 3: Simplified representation of a POL deployment, based on GPON, which can be used in a building or campus. FIGURE 4: Upgrading the network for new services requiring dedicated higher bandwidth and speeds. One of the key benefits of POL solutions and GPON technologies, the evolution can happen gradually, adding additional capabilities only where the network needs more throughput. EVOLUTION TO NEXT-GENERATION PON TECHNOLOGIES Here is a simplified representation of a POL deployment, based on GPON, which can be used in a building or campus. The OLT is installed in the central equipment room and 8 ONTs are connected via a splitter to a PON port as shown in Figure 3. GPON provides 2.5 Gb/s to the ONTs downstream. What if new services are introduced that require dedicated/higher bandwidth and greater speeds? A smooth, targeted and cost-efficient evolution of the network can be achieved without the need for a forklift upgrade. Upgrading the network can be done in three steps as depicted in Figure 4: 1. Add a co-existence element (CE) in the central equipment room to combine GPON with XGS-PON wavelengths. This is a wavelength division multiplexer (WM) that can take multiple wavelengths and put them on the same optical fiber. It is defined by ITU standards. 2. Equip the OLT with XGS-PON line cards and connect the 10G PON ports to the CE so that 10G PON symmetrical capabilities are delivered on the same optical fiber and splitter. 3. Replace GPON ONTs with 10G PON ONTs for those services demanding greater speeds.