• 1. What is GPON?
    • GPON stands for Gigabit Passive Optical Network. The GPON network delivers broadband services to network devices without employing active electronics between the Optical Network Terminals (ONT) situated at the end-user location and the Optical Line Terminal (OLT) generally situated in the MDF/data center. A fiber-optic cable connecting OLT and ONT is used to carry a wavelength downstream. By using a passive splitter the downstream data originating from the OLT can be distributed as part of a point-tomultipoint architecture. The upstream data running from the ONT to OLT – which is delivered on a separate wavelength to avoid collisions with the downstream transmission – is aggregated by the same passive splitter unit, which also carries out the recombining function. This enables data to be collected by the OLT over the same single fiber that sends the traffic downstream. GPON supports bandwidth of 2.4Gbps downstream and 1.2Gbps upstream that can be shared between up to 64 ONTs.


      A typical OLT base configuration provides multiple Wide Area Network (WAN) interfaces (e.g., 2x10GigE or 12x1GigE) and up to 56 GPON interfaces that can support up to 3,584 Optical Network Terminals (ONT). Fiber Distribution Hubs (FDH) are used to house the passive optical splitters. At the user end of the GPON, the ONT provides an intelligently managed demarcation point for network services. The maximum distance from the OLT to the ONT is nominally 24 miles. From the ONT, the end-user has access to standard RJ-45 ethernet ports (10/100/1000Base-T). The ONT itself has no user controls and is managed from the element management software.
  • 2. What are some of the benefits of a GPON Solution?
  • 3. Do we need to deploy new fiber up the riser for the GPON solution? What kind of fiber do we have to deploy? What are the benefits of deploying such fiber?
  • 4. Fiber optic cabling is more fragile than copper. How do we handle this?
    • The bend insensitive fiber available today (e.g., Corning ClearCurve) is much more durable and resilient than CAT6. It has a tighter bend radius, higher tensile strength and is not subject to crimping.
  • 5. The GPON solution is too new a technology for us. We have been using the traditional workgroup switches for a long time. We feel it would require lot of time and training for us to understand and maintain this system. Plus in the GPON solution we will have to manage many ONTs. Will it will require a lot resources to manage all of the devices?
    • The GPON solution is relatively simple to operate and maintain compared to traditional workgroup solutions. The solution comes with a management system that provides an extremely user friendly GUI that can be used to configure and manage the entire network from a single point – perform fault management, keeping track of s/w releases, perform software upgrades on all the ONTs from one single place. In a traditional network, the IT managers have to keep track of various s/w releases on various switches in their access and distribution layer by themselves and then use various costly tools to isolate the faults between the devices.
  • 6. How do I manage the system? I don't have the expertise to run a Solaris O/S management system?
    • The GPON solution comes with an integrated Element Management System!(EMS). The software provides full FCAPS (Fault, Configuration, Administration, performance and Security) management for the GPON solution. it includes an interactive, intelligent java application that provides a graphical user interface (GUI) using familiar point-and-click-navigation style.
  • 7. How do we power our VoIP phone using the GPON solution?
    • The GPON includes an ONT that offers POE for the attached devices. It also includes an integrated battery backup unit for power redundancy purposes and it will also power the VoIP phones using the POE interface ports.
  • 8. The power savings isn't real if I have powered phones that offset the POE switch savings.
    • The greatest advantages to deploying GPON technologies within the LAN environment are, the elimination of active electronics within the infrastructure, its ability to bring fiber to the desktop efficiently, future-proofing of said infrastructure, and!the cost savings!specific to!installation cap-ex as well as op-ex. Power consumption is greatly reduced due to the elimination of workgroup switches and environmental controls in the riser closets. We estimate savings of about 10% to 33% depending upon the size of the office building. The desktop terminal with 4x10/100/1000bawseT only draws 10 watts and can be used to “light up” up to 4 offices/cubes. So total power consumption to service 48x10/100/1000BaseT ports in our solution would be 120 watts (12 ONTs with 4x1Gbe ports each at 10 watts per port), which is significantly less than the traditional work group solution.
  • 9. Currently all of our battery backup and UPS systems are located in one place. With ONTs located near the end-users we will have batteries for backup every where on the floor. It would be very difficult for us to manage.
    • Due to the elimination of the electronic switches in the IDF closets and the subsequent battery back and UPS units, the network designers and architects do not have to worry about designing the extra power circuits to supply power to the workgroup switches and can realize tremendous cost savings by eliminting these out from their design. In addition they do not have to design the cooling requirements for these IDF closets resulting in the additional power savings from the reduced HVAC equipment. The battery backup unit on the ONTs are integrated however the choice of putting the batteries in these units lies with the IT managers. We believe that they should put the batteries into the ONTs of users who require their phones to be working during the power outage. In addition the Element Management System keeps track of the state of the all the batteries and provide requisite alarms to help with the management of these batteries.
  • 10. How secure is a GPON solution?
    • The GPON solution provides 128 bit AES encryption between the OLT and ONT to prevent man-in-themiddle attack. Also, it supports 802.1x authentications to provide port based Network Access Control. In addition, fiber is inherently more immune to wire-tapping kind of attacks compared against the traditional copper cabling solution. Lastly it supports features like IP ACLs, Broadcast limiting and MAC address limiting to secure the network from unauthorized users.
  • 11. How do you provide high bandwidths of at least 100Mbps to each user. Do we have to limit the number of splits on the PON or what other mechanisms can be used?
    • The GPON solution can be configured to provide up to 1Gbps guaranteed bandwidth per user. Even in the traditional workgroup switch solution, the LAN is engineered with massive over-subscription – generally 1Gbps for every 48 users. Each PON port on the OLT provides 2.4Gbps downstream and 1.2Gbps upstream. The PON port (or bandwidth) can then be optically shared between up to 64 optical network terminals. The GPON solution provides the capability to configure the committed information rate (CIR) to guarantee a minimum amount of bandwidth per Ethernet port on the ONT but it is also balanced by the peak information rate (PIR) allowing users to burst traffic up to a specified limit of 1Gbps. The burst nature of the data traffic would make limiting the splits on a PON unnecessary.
  • 12. I still need a Layer-3 router? Wouldn"t that router become bottleneck for all my traffic?
    • The GPON solution does require a Layer-3 router attached upstream to the OLT. The current workgroup based design is usually over-subscribed at various levels starting from individual workgroup switches to the Layer-3 router at the data center all being heavily over-subscribed. Most of the computer originated or client-server!based data does not "live" within the local area network anyways so it is very important to identify the per user bandwidth requirement as well as application bandwidth requirement in order to correctly size any and all connections.
  • 13. How do I ensure that voice traffic is prioritized over data traffic?
  • 14. Does the GPON solution support the use of Cisco IP Phones?
    • The GPON solution can be deployed with Cisco phones. It can be deployed with a Cisco router in the core and the Cisco IP Phones and will work without any issues.
  • 15. We have intelligent feature rich workgroup switches today. How will replacing them impact my network?
    • With the GPON solution, the VLANs will be managed by the core router/switch just like they are managed in traditional LAN architecture with workgroup switches. Most of the computer originated or clientserver! based data does not "live" within the local area network anyways making the core router/switch the correct place to add intelligence. The GPON solution is merely a Layer-2 transport network that extends the intelligence of the core router all the way to the desktop.
  • 16. How can I get physical redundancy to critical locations in my LAN using the GPON solution?

Copyright © 2011-2014 SPADA Innovations, Inc. All rights reserved.