WO2013059486A2

WO2013059486A2 - Systems, methods and apparatuses for providing data communication over ethernet passive optical networks

Info

Publication number: WO2013059486A2
Application number: PCT/US2012/060861
Authority: WO
Inventors: Christian RATAJCZAK; Marlin DAVIS; Jacob ERAKLIDIS
Original assignee: Quantabits Inc.
Priority date: 2011-10-18
Filing date: 2012-10-18
Publication date: 2013-04-25
Also published as: WO2013059486A3

Abstract

An apparatus for collecting and distributing data over an optical fiber network includes an instructions for an interface communicable to a computing device enabling the computing device to define bandwidth provisioning information for a service level agreement and to assign the service level agreement to one or more optical network units connected to the apparatus.

Description

SYSTEMS, METHODS AND APPARATUSES FOR PROVIDING DATA

COMMUNICATION OVER ETHERNET PASSIVE OPTICAL NETWORKS CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.

61/548,497, filed October 18, 2011, and U.S. Application No. 13/652,086, filed October 15, 2012, the entire contents of each of which are incorporated by reference herein in their entirety.

FIELD

[0002] This application relates to systems, methods and apparatuses for establishing networks for communicating data over optical fiber. DESCRIPTION OF RELATED ART

[0003] Optical fiber networks are in common use for efficiently transmitting and receiving data over large distances. In optical fiber networks, data is encoded as modulated electromagnetic waves, typically in the range of 800-1700nm, and most typically having wavelengths in the range of 1200-1700nm.

[0004] Over time, different approaches have been proposed for providing optical fiber network connectivity to end users. For example, optical fiber may be deployed to the neighborhood of a user, to the home or premises of a user, or even to the desk or television screen of the user. In an example where fiber is provided most of the way, but not all of the way to a user's network connected device (such as a computer, a television set-top box, an Ethernet network router or a switch), a transition from the optical fiber network to a conventional copper network (such as Ethernet, for example) or a wireless network (such as WiFi, WiMax, etc.) is typically necessary.

5] A Passive Optical Network (PON) is one among several architectures that can be used in such fiber-to-the-home (FTTH) applications. PON has been described for FTTH as early as 1986. PON -based FTTH is today the main choice of many Network Services Providers (NSPs) since it breaks through the economic barrier of traditional Point-to -Point (P2P) solutions. PON based FTTH provides a powerful Point-to-Multipoint (P2MP) solution to satisfy the increasing demand in the access of the communication infrastructures between Central Office (CO) and customer sides. PON is a technology viewed by many as an attractive solution to the first mile problem; a PON minimizes the number of optical transceivers, CO terminations and fiber deployment. A PON-based FTTH is a P2MP optical network with no active elements in the signal path from source to destination. The only interior elements used in a PON-based FTTH are passive optical components, such as optical fiber, splices and splitters. A PON-based FTTH employs a passive device that does not require any power (i.e., optical splitter/branching device, etc.) to split an optical signal from multiple fibers into one. PON-based FTTH is capable of delivering triple-play (data, voice and voice) services at long reach up to 40 km between CO and customer including splitters. All transmission in a PON-based FTTH is performed between an Optical Line Terminal (OLT) and Optical Network Units (ONUs). OLTs may reside at a CO, while ONUs may be located at an end-user location to transition from the optical network to a wireless or wired network. [0006] Currently, PON-based FTTH is commonly deployed because it offers a cost-efficient and scalable solution to provide huge-capacity optical access. The cost effectiveness of PON-based FTTH depends on numbers of ONUs per OLT optical transceiver, the cost of fiber and its installation. The PON solution benefits from having no outside plant electronics to reduce the network complexity and life-cycle costs, while improving the reliability of FTTH. The introduction of PON-based FTTH allows a network to transport huge amounts of data and provide communication services that play a very important role in many of our daily social and economic activities.

[0007] However, the installation and configuration of a PON-based FTTH solution is not trivial and today may contribute to a significant portion of the cost and time needed to implement a PON-based FTTH solution. Network reliability and troubleshooting are also issues of deep concern to network operators being eager to deploy high capacity fiber networks, since a single failure in the network could result in significant losses of revenue.

[0008] Network reliability is an issue of deep concern to network operators being eager to deploy high capacity fiber networks, since a single failure in the network could result in significant losses of revenue. The importance of network reliability will keep pace with the steadily increasing network capacity. For very-high-capacity future optical networks, carrying multitudes of 10 Gbps channels per fiber strand, a failure of optical connection will interrupt a vast amount of services running on-line, making the connection availability a factor of great significance.

[0009] Troubleshooting a PON-based FTTH involves locating and identifying the source of an optical problem in what may be a complex optical network topology that includes several OLTs, optical splitters, fibers and ONUs. Since most components in the network are passive, a large part of the issues may be due to dirty, damaged or misaligned connectors or breaks or macro-bends in the optical fiber cables. These issues may affect one, some or all subscribers on the network, depending on the location of the problem. If a fiber breakdown or cut occurs in the feeder region (from OLT to optical splitter), all downstream signals toward ONUs may be be affected. However, if a problem such as macro bending or dirty connector causes optical power to be lost somewhere in the network, only a number of ONUs may be affected. Since the attenuation in optical fiber cables is proportional to length, distant ONUs receive a weaker downstream signal than closer ones. The upstream signals received at CO from more distant ONUs are also weaker, and the OLT will detect such decreased performance.

[0010] In order to facilitate effective and prompt network protection and restoration, it is highly desirable to perform network survivability measures in the optical layer. This can be achieved by simple fiber link or equipment duplication with protection switching or some other intelligent schemes with minimal resource duplication or reservation for protection. For PON applications, equipment failure at either OLT or ONU can be easily remedied by having a backup unit in the controlled environment. However, for any fiber cut, it would take a relatively long time to perform the repair. Therefore, it is highly desirable to have survivable PON architectures with protection switching against any fiber cut survivability.

[0011] Solutions are needed to provide simple and reliable tools for implementing, configuring and troubleshooting PONs. BRIEF SUMMARY

[0012] This invention relates to systems, methods and apparatuses for establishing networks for communicating data over optical fiber.

[0013] In general, in one aspect, the invention features an apparatus for collecting and distributing data over an optical fiber network, the apparatus including a processor, a local network adapter configured to send and receive data to a computing device, an upstream network adapter configured to send and receive data over an upstream optical fiber network, a downstream network adapter configured to send and receive data over a downstream optical fiber network to at least one optical network unit and a local storage comprising instructions which, when executed by the processor, are configured to provide an interface to the computing device, wherein the interface is configured to accept bandwidth provisioning information, entered by a user using the computing device, and storing said bandwidth provisioning information as a service level agreement in the local storage, and the interface is configured to accept a command, entered by a user using the computing device, to assign a service level agreement to the optical network unit and store a related assignment record in the local storage along with an identification of the optical network unit.

[0014] Implementations of the invention may include one or more of the following features. The bandwidth provisioning information may include a minimum data rate at which an optical network unit will operate. The bandwidth provisioning information may include a committed data rate for an optical network unit which is equal or greater than the minimum data rate. The bandwidth provisioning information may include a maximum data rate at which an optical network unit will operate. The apparatus may be connected via one of the upstream optical fiber network and the downstream optical fiber network to an optical line terminal, and the interface may be configured to provide status information for the optical line terminal to the computing device. The apparatus may be connected via one of the upstream optical fiber network and the downstream optical fiber network to an optical line terminal, the interface may be configured to accept settings information, entered by a user using the computing device, for the optical line terminal, and the interface may be configured to transmit the settings information to the optical line terminal. The apparatus may be connected via the downstream optical fiber network to at least a first optical network unit and a second optical network unit, the interface may be configured to accept a command, entered by a user using the computing device, to assign the first service level agreement to the first optical network unit and store a related assignment record in the local storage along with an identification of the first optical network unit, and the interface may be configured to accept a command, entered by a user using the computing device, to assign the first service level agreement to the second optical network unit without requiring bandwidth provisioning information in addition to the bandwidth provisioning information stored as the first service level agreement and store a related assignment record in the local storage along with an identification of the second optical network unit. The interface may be configured to accept second bandwidth provisioning information, entered by a user using the computing device, and storing said second bandwidth provisioning information as a second service level agreement in the local storage, the interface may be configured to accept a selection of a service level agreement, entered by a user using the computing device, from among the first service level agreement and the second service level agreement, and the interface may be configured to assign the selected service level agreement to the optical network unit and store a related assignment record in the local storage along with an identification of the optical network unit. A plurality of service level agreements, including the first service level agreement, may be stored in the local storage, each of the plurality of service level agreements may include weight information, the apparatus may be connected to a plurality of optical network units via the downstream optical fiber network, the interface may be configured to accept a selection of a service level agreement for each of the plurality of optical network units from among the plurality of service level agreements, and the apparatus may be configured to allocate extra bandwidth among the plurality of optical network units based on weight information included in the service level agreement selected for each of the optical network units.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 illustrates an overall arrangement of a data network according to an exemplary embodiment of the present invention;

[0016] Figure 2 illustrates an overall arrangement of a data network according to another exemplary embodiment of the present invention;

[0017] Figure 3 illustrates an overall arrangement of a data network according to yet another exemplary embodiment of the present invention;

[0018] Figure 4 is a notional block diagram of an optical line terminal according to an exemplary embodiment of the present invention; [0019] Figures 5-11 illustrate various examples of interfaces provided by an optical line terminal to a connected computing device according to exemplary embodiments of the present invention;

[0020] Figure 12 illustrates link margin and power margin for each transmission line in a PON-based FTTH according to an exemplary embodiment of the present invention;

[0021] Figure 13 illustrates optical power of each transmission line in a PON -based FTTH with different splitting ratios according to an exemplary embodiment of the present invention;

[0022] Figure 14 illustrates optical power of each transmission line in a PON-based i- FTTH with different splitting ratios according to an exemplary embodiment of the present invention;

[0023] Figure 15(a) shows the view of a dirty connector as seen in a fiber probe viewer according to an exemplary embodiment of the present invention; and

[0024] Figure 15(b) shows the view of the dirty connector as seen in a fiber probe viewer after being cleaned by using fiber cleaner according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

[0025] Referring to Figure 1, a data network 10 may include one or more Optical Line Terminals (OLTs) 12 connected to one or more Optical Network Units (ONUs) 14 by optical fiber 16. Passive optical splitters 18 may be employed between the ONTs 12 and the ONUs 14. In the example shown in Figure 1, ONUs 14 are connected via wired Ethernet 20 to WiMAX base stations 22. WiMAX base stations 22 provide wireless network connectivity to a variety of user devices and premises 24, including computers, mobile devices, Wifi routers, television set-top boxes, etc.

[0026] In the example shown in Figure 1, the OLT 12 is connected via wired Ethernet 20 to a router 28, which provides connectivity to the internet 30 via wired Ethernet 32.

[0027] In another example, shown in Figure 2, a data network 10 includes ONTs 12a and 12b connected to ONUs 14a-14f by optical fiber 16, with splitters 18 dividing the signals from the ONTs among the ONUs. In addition, splitters 18 may be configured to combine signals from the ONUs as they are transmitted back to the ONTs. From the ONUs, data is communicated via wired Ethernet 20 or by wireless communication 36 to and from a variety of user devices 24. ONTs may be connected to a central office 34 by optical fiber 16 or wired Ethernet 20, or both.

[0028] ONUs may be configured to connect to one or more ONTs. For example, ONU 14a may be configured to connect to both ONT 12a and ONT 12b. In the example shown in Figure 2, such configuration provides independent communication paths back to the central office 34. Such configuration may be configured to provide, for example, additional bandwidth, additional stability in the form of redundant connections and the ability to take one communication path down for maintenance without severing the data connection.

[0029] The types of user devices 24 which may be configured to connect to the ONUs are not limited. For example, a router 24a may be configured to provide connectivity to other user devices through wired Ethernet or wireless communication. A Television 24b or television set-top box may be configured to connect to an ONU 14c to display video and audio information communicated over the network 10. A Local Area Network (LAN) 24c may be connected to an ONU 14a, for example, to provide voice and data communication to an office building over the network 10. A personal computer (PC) 24d may be connected to an ONU 14d to provide voice, data or video connectivity over the network. In addition, a device, such as PC 24d may be connected to more than one ONU, for example ONUs 14d and 14e in Figure 2. Similarly, an ONU may be connected to more than one user device. For example, as shown in Figure 2, ONU 14e is configured to communicate with PCs 24d and 24e as well as wireless base station 24f.

[0030] ONTs may also be configured to communicate wirelessly with user devices. For example, as shown in Figure 2, ONU 14f includes an antenna and is configured to communicate via wireless communication 36 with one or more user devices 24.

Fiber optic cables 16 may be Single-mode Simplex with SC connectors. Optical splitters 18 may be configured to pass wavelengths used in EPON. In one example, the wavelengths used in an EPON are 1490 ±10nm for downstream and 1310 ±50nm for upstream.

[0031] EPON systems are typically configured to transmit data over long distances, for example 40km or more. This long distance communication is made possible due to highly amplified lasers and very sensitive receiving sensors. To protect sensors on the PON network, attenuation between source and receiver may need to be controlled, for example, to at least 14db. Fiber optic cables will typically provide 0.2 to 0.3db of attenuation per kilometer. Each 2-way split on a fiber optic splitter may also provide 3db of loss. To calculate the loss from the splitter, Equation 1 may be used:

Loss = log₂(NP) x LS Equation 1 where NP is the number of downstream PON ports on the splitter and LS is the loss per two way split in the splitter. In some cases, the addition of an attenuator in the optical path is necessary to maintain a minimum attenuation in the optical path.

[0032] OLTs may be configured to manage the ONUs connected to them and to provision bandwidth to the various ONUs based on predetermined or dynamically adjusted settings. Figure 3 provides a detailed schematic of a typical OLT-ONU connection according to the present application. As shown in Figure 3, an OLT 12 and an ONU 14 are each connected to an optical splitter 16 via an optical fiber. The OLT 12 is connected to an upstream network 38 by either an optical fiber or an Ethernet cable. The OLT 12 may also be connected to a management or provisioning network 40 by an Ethernet cable. A computing device, such as a personal computer, mobile device, etc. may also be connected to the management or provisioning network 40. Alternatively, the OLT 12 may be directly connected to a computing device. The ONU 14 may be connected via a fiber or Ethernet cable to a downstream device or network 24.

[0033] An OLT may be provided with an embedded web server to provide an interface to computing devices connected to the OLT directly or through the management or provisioning network. Such web server may be in the form of a computer program stored in local storage of the OLT and executed by a processor of the OLT. Figure 4 shows a schematic example of components which may be included in an OLT 12. An OLT may include a processor 42, local storage 44, a local network adapter 46 for connecting to management or provisioning networks and devices, one or more upstream network adapters 48 for connecting to upstream networks and devices and one or more downstream network adapters 50 for connecting to downstream networks and devices. Each upstream and downstream network adapter may include a transmission part TX and a receiving part Rx.

[0034] As mentioned above, a web server of an OLT may be configured to enable computing devices connected to the OLT through the local network adapter to configure settings of the OLT. In the present application, it will be understood that any device described as being connected to the OLT through a local network adapter may be connected directly or may be connected through a management or provisioning network.

[0035] Upon application of power to the OLT, or upon receipt of a reset command, the OLT may be configured to obtain an IP address from a Dynamic Host Configuration Protocol (DHCP) server connected to the local network adapter of the OLT. In the event that no such DHCP server is connected to the OLT, or if the OLT is unable to find or communicate with a DHCP server connected to the OLT, the OLT may be configured to assume a predetermined IP address. To initiate a connection to the OLT, a computing device connected to the local network adapter of the OLT may send a request, using a suitable web browser (such as Chrome, Firefox or Internet Explorer, for example) for the IP address of the OLT. Upon receipt of such request, the OLT may be configured to present to the web browser of the computing device an interface for configuring one or more settings of the OLT.

[0036] Figure 5 shows an example of one such interface, in the form of a graphic, interactive web page which may be presented to a connected computing device. In the example shown in Figure 5, an overview of the status of OLTs connected to the data network is presented as a web page. The OLTs of a data network may be configured to communicate status and configuration information with one another so that a computing device connected to a single OLT may observe and change the various settings of the other OLTs connected to the data network. In the example shown in Figure 5, the information presented to the connected computing device is:

QB Sw Version: current Software Version

MAC: MAC Address of the Management Port

Uptime: Current uptime of the OLT in seconds

DevicelD: A Combination of Slot Number and Device Number

ChipSet ID: Internal Chip set ID

Slot Number: A single OLT box has a slot Number of 0; in a concentrator solution each blade will increment the slot number starting from 0

Device Number: This represents both an OLT and the physical Chip on the 8022-8XX-OLT; each Chip/OLT can handle 4 ports

Firmware version: Operating System version

DBA: Provisioning Software Version Configuration version: Internal start up configuration version

DevicelD Status: Up, Initializing, or Down, defines if the OLT is connected and running or the OLT is down and not responding to requests.

[0037] It will be understood that more or less information may be communicated to a connected computing device in other embodiments. The web page presented to the connected computing device may be interactive. For example, if a user clicks on "OLT:0" on the left hand side of the web page shown in Figure 5 using a pointing device or similar instrument connected to the computing device, the web server may be configured to present a web page to the connected computing device giving details of the properties of OLT 0. Figure 6 shows an example of a web page which may be presented to a connected computing device that shows detailed status information relative to ONU 0. A web page may also include various command inputs. For example, as shown in Figure 6, a web page may include a command input for resetting the OLT 52 and a command input for enabling or disabling the OLT 54.

[0038] As another example of interactivity, if a user clicks on "PON #0" on the left hand side of the web page shown in Figure 5 or the web page shown in Figure 6 under "OLT:0" using a pointing device or similar instrument connected to the computing device, the web server may be configured to present a web page to the connected computing device giving details of the properties of PON 0 connected to OLT 0. Figure 7 shows an example of a web page which may be presented to a connected computing device that shows detailed status information relative to PON 0. In the example shown in Figure 7, the information presented to the connected computing device is:

LLID: The LLID is an identifier assigned by the OLT and is used to uniquely identify ONUs on the PON

MAC: MAC Address of the ONU

Register/Deregister button: Comparable to a soft Reset since an ONU is usually offsite (if the

ONU is connected the ONU will reregister automatically)

SLA: A Service Level Agreement that defines bandwidth guidelines

Enabled: True/False, Enable or Disable upstream traffic

Properties button: Presents you with a dialog box where you can assign a SLA profile to the specified ONU. [0039] As a further example of interactivity, if a user clicks on the "Properties" button 56 on the right hand side of the web page shown in Figure 7 to the right of the first row of information using a pointing device or similar instrument connected to the computing device, the web server may be configured to present a web page to the connected computing device giving details of the properties of the ONU which is assigned LLID 3 on PON 0 connected to OLT 0. Figure 8 shows an example of a web page which may be presented to a connected computing device which shows detailed status information relative to the ONU that is assigned LLID 3 on PON 0 connected to OLT 0. The information shown in Figure 8 may overlap with the information shown in Figure 7, and may include additional information or command inputs, such as, for example, a drop down menu 58 allowing a user to select an SLA to apply to the ONU from among a list of SLAs.

[0040] In another example of a web page that may be presented to a computing device connected to the local network adapter of an OLT, Figure 9 shows a web page which is configured to display a list of ONUs that were registered at one point on the OLTs in the data network, but are currently not connected. The OLTs may be configured to automatically save the SLA settings based on the ONU's MAC address. This allows the OLTs to remember the specific SLA settings for each ONU and dynamically reconfigure them. For example, once the ONU is reconnected to a PON, the SLA may be automatically reapplied to the ONU. The web page shown in Figure 9 may be accessed, for example, by a user clicking on the "Unregistered ONUs" hyperlink at the left hand side of any of the web pages shown in Figures 5-7. [0041] SLA profiles may be edited by a user through a dedicated SLA Profiles web page. In the example shown in Figure 10, a web page lists all the saved SLA profiles stored in the local storage of the OLTs. This web page may be configured to allow a user to add, edit or delete SLA profiles. This webpage also may be configured to list all or some the attributes of the SLA profiles for easy viewing. The web page may include an edit button 60 which may be configured to bring up an SLA editing page that may be configured to allow a user to change specific settings within the each SLA profile. The web page shown in Figure 10 also includes command inputs for adding 62 and deleting 64 an SLA profile to or from the local storage of the OLTs. The web page shown in Figure 10 may be accessed, for example, by a user clicking on the "LLID SLA Profiles" hyperlink at the left hand side of any of the web pages shown in Figures 5-7.

[0042] Figure 11 shows an example of a dialog box which may be presented upon a user clicking on the "Add Profile" command input 62 shown in Figure 10. The dialog box may prompt a user to enter information or settings concerning the SLA profile to be added, for example:

Profile Name: This name should be unique from all other Profile Names

Fixed Information Rate Speed (kilobytes): The Fixed Rate may be the minimum speed that the ONU will operate at. STATIC: High priority data (Voice and Video)

Committed Information Rate (kilobytes): The Committed Rate can be equal or greater value of than the Fixed Rate. ASSURED: Guaranteed

Peak Information Rate (kilobytes): The Peak Rate may be the maximum speed that the ONU can operate at and may be used for oversubscribing users in the network. BEST EFFORT:

Over subscription Weight: The weight parameter may be used to support fairness when there exists remaining bandwidth in the system and ONUs may compete for the extra bandwidth. Each of the provisioned weight values may be divided by the sum of the entire system's weight values to generate a percentage of bandwidth that will be allocated to any given ONU. The sum of all ONUs give the overall system's fairness response (1 = default; it is recommended to keep Weight its default value)

[0043] Accordingly, provisioning data communication services through OLTs and ONUs via a graphical user interface of the type proposed herein is a simple task for network personnel. Network personnel are provided with the tools to provision data communication services over an entire network from a single computing device, without having to travel from site to site.

[0044] In another example, the interface provided to a connected computing device from an OLT may provide pass-through access to other network connected devices or peripherals. For example, with reference to Figure 2, a computing device connected to OLT 12a may be provided pass-though access to configuration settings for router 24a. In one example, such pass-through access may be provided via Hypertext Transfer Protocol (HTTP) or other standardized communication protocol.

[0045] A key to managing or increasing overall network distance is optical power budget, i.e., the amount of light available to make a fiber optic connection. Optical loss or total attenuation is the sum of the losses of each individual component between a transmitter and receiver including fiber, splices, couplers and other optical devices. The loss is relative to the transmitter output power and affects the required receiver input power. Loss budget calculation analysis is the calculation and verification of a fiber optic system's operating characteristics. Transmitter launch level power, receiver sensitivity and the dynamic range are crucial numbers used in span analysis. The overall span loss or link budget can be determined using an optical power meter to measure the true loss or by computing the loss of system components. Typically, the safety margin sets aside 3 dB. This number will be different for every organization depending on how much risk it wants to assume in its network. To guarantee error free operation, a value no less than 1.7 dB should be used. This safety factor is subtracted from the remaining power from above. If the number is still positive after considering all loss and attenuation, one can be assured that the fiber network will deliver the required performance over the life of the installation.

6] Power at a particular wavelength generated by the transmitter Light Emitting Diode (LED) or Laser Diode (LD) used to launch the signal is known as the transmitter launch level. Receiver sensitivity and dynamic range are the minimum acceptable value of received power needed to achieve an acceptable Bit Error Rate (BER) or performance. Receivers have to cope with optical inputs as high as -5 dBm and as low as -30 dBm, the receiver needs an optical dynamic range of 25 dB. To ensure that the fiber system has sufficient power for correct operation, a span's power budget, which is the maximum amount of power it can transmit, is calculated. From a design perspective, worst case analysis calls for assuming minimum transmitter power and minimum receiver sensitivity. This provides for a margin that compensates for variations of transmitter power and receiver sensitivity levels. With minimum transmit power and minimum receive sensitivity data, one can calculate the available light. Factors that can cause span or link loss include fiber attenuation, splice loss, connector loss, chromatic dispersion and other linear and non-linear losses. Power margin, PM, represents the amount of power available after subtracting linear and nonlinear span losses from the power budget.

[0047] The power budget may be calculated according to Equation 2: Pjj = P_TMIN^— P_RMIN Equation 2 where P_B is the power budget, P_TMIN is the minimum transmitter power and P_RMIN is the minimum receiver sensitivity.

[0048] Link margin may be calculated according to Equation 3 :

Ps = (FATT F_L) + (SLOSS X S_N0) + (C_Loss x C_N0) Equation 3 where Ps is the link margin, FA_TT is the attenuation per unit length of the fiber, F_L is the length of the fiber, S_LOSS is the splice loss, SNO is the number of splices, C_LOSS is the connector loss and C_NO is the number of connectors.

[0049] Power margin may be calculated according to Equation 4:

PM = PB - Ps - SM Equation 4 where S_M is the safety margin.

[0050] Fiber link loss measurements may be carried out using a laser source and a power meter in both directions on each fiber span to ensure that the actual link loss is less than the budgeted loss. An important part of preparing a high speed transmission network is developing and adhering to fiber cleanliness standards. Dirty optical connectors are a common cause of failures over time. Furthermore, they contribute to Optical Return Loss (ORL), which may increase noise and result in higher Bit Error Rate (BER).

[0051] In one example, the minimum transmitter power and minimum receiver sensitivity is set as 0 and -34 dBm. The available power or power budget for the designed architecture therefore is 34 dBm, and the dynamic range may be configured as 31 dBm with safety margin 3 dBm. Typical available splitting ratios of lxN passive optical splitters are 1x4, 1x8, 1x16, 1x32, 1x64 and 1x128. Commercial PON-based FTTH network systems commonly use the 1x16 or 1x32 splitting ratio. The splitting ratio affects the power budget in PON-based FTTH network system. A higher splitting ratio means that the cost of OLT is better shares among ONUs and the OLT bandwidth is shared among more ONUs, thus less bandwidth per user.

Table 1 : Theoretical loss for a lxN optical splitter

Table 2: Link margin and power margin for 1 :8 splitting ratio

[0052] Loss is a concern, and any extra loss in power directly brings in reduction of number of subscribers to NSPs. This becomes a permanent loss to the NSPs. Table 1 lists the theoretical loss for lxN optical splitter. Table 2 shows the link margin and power margin for each transmission line in a PON-based FTTH as shown in shown in Figure 12. The link margin for triple-play signals will increase by 3 dB as the splitting ratio of lxN optical splitter increases twice.

[0053] The insertion loss for each component used in PON-based FTTH and PON-based z^'-FTTH is listed in Table 3. The average exact measured optical power, power budget and dynamic range of each transmission line in PON-based FTTH and PON-based i-FTTH with different splitting ratios are summarized in Table 4 as well as in Figures 13 (PON -based FTTH) and 14 (PON-based i-FTTH). The average exact optical power or total system loss may be determined by using an optical power meter (for 1310, 1490 and 1550 nm) and OTDR (for 1625 nm). The two most common tools used for fiber optic cable testing are optical power meter and OTDR. Both can measure attenuation (signal loss) on a fiber optic link, yet they usually provide different results.

Table 3 : Insertion loss of each component

Table 4: Loss Measurement in both networks with 1 :8 splitting ratio

[0054] When a power meter and a light source are used to measure the loss in a fiber optic link, they closely model what the final installed equipment will do. A signal is sent from one end (source) to the other end (receiver or power meter), and power lost in the link due to attenuation is measured. However, an OTDR works on a completely different principle. There are a few reasons OTDR provides a significant difference from power meter when loss is measured on single mode fiber optic links. These differences include backscatter versus through measurements, receiver saturation, trace interpretation, and launch cables and far-end connectors.

[0055] Fiber optic communication is achieved by transmitting a beam of light down an optical fiber cable. Dirt, dust and other particles on fiber end faces are common causes of problems in optical network fiber. Typical fiber optic cores (signal carrying portion) are 9 μιη for single mode and 62.5 μιη for multimode. This makes cleanliness of optical connections extremely important. Common contaminates such as dust, dirt, oils, etc. may be larger than 9 μιη and can attenuate or completely block an optical signal much like dirt attenuates visible light transmitted through windows. Many optical networks have tight loss budgets. Dirty connectors can quickly exceed the allowed loss. Dirty connectors are a common cause of costly down time for networks. A few of the common connector contaminates are listed below:

[0056] Dust and Dirt: Dust and dirt are a fact of life. There are always particles airborne and on surfaces. Slight air currents can transport them to exposed fiber optic connectors.

[0057] Metallic Particles: Connector bodies are fiber housings commonly made from plated metal (especially military connectors). Normal wear and tear will scrape off the platting in tiny particles. Normal wear and tear of hand tools can also produce tiny metal particles. Metal particles are similar to dirt with two exceptions: (i) a charged connector (easily produced by dry wiping) is a magnet for metallic particles which will jump to an electro-statically charged connector and (ii) metallic particles are by nature abrasive, and dry wiping can cause the fiber end to be scratched and damaged by metallic particles. 8] Oils: Human skin is naturally oily. Contact with an optical connector likely results in instant contamination of the connector end face. Proactively inspecting and cleaning fiber connectors enables field engineers and technicians to reduce network troubleshooting and downtime, optimizes signal performance and prevents network damage. A fiber inspection probe (FIP) is used to inspect both male (patch cord) and female (bulkhead) sides of a fiber interconnect. Cleaning connectors is quick and inexpensive since network downtime and service calls are costly. It is a good practice to clean and inspect connectors each time they are disconnected. A patch cord cable and optical fiber line composed of 1 and 2 km length, respectively, with clean and dirty connectors are inspected with a FIP and shown in a fiber probe viewer (Figures 15(a) and 15(b)). Figure 15(b) shows the view of the dirty connector after cleaned by using fiber cleaner. The effect of clean and dirty connectors to optical signal level is listed in Tables 5 and 6.

Table 5: Loss comparison for lm patch cord and 2km optical fiber with clean and dirty connectors

Table 6: Loss comparison for 2km optical fiber line with different modulation sources

[0059] In addition, the embodiments and examples above are illustrative, and many variations can be introduced to them without departing from the spirit of the disclosure or from the scope of the appended claims. For example, elements and/or features of different illustrative and exemplary embodiments herein may be combined with each other and/or substituted for each other within the scope of this disclosure.

Claims

What is claimed is:

1. An apparatus for collecting and distributing data over an optical fiber network, the apparatus comprising:

a processor;

a local network adapter configured to send and receive data to a computing device;

an upstream network adapter configured to send and receive data over an upstream optical fiber network;

a downstream network adapter configured to send and receive data over a downstream optical fiber network to at least one optical network unit; and

a local storage comprising instructions which, when executed by the processor, are configured to provide an interface to the computing device, wherein

the interface is configured to accept bandwidth provisioning information, entered by a user using the computing device, and storing said bandwidth provisioning information as a first service level agreement in the local storage, and

the interface is configured to accept a command, entered by a user using the computing device, to assign the first service level agreement to the optical network unit and store a related assignment record in the local storage along with an identification of the optical network unit.

2. The apparatus of claim 1, wherein said bandwidth provisioning information includes a minimum data rate at which an optical network unit will operate.

3. The apparatus of claim 2, wherein said bandwidth provisioning information includes a committed data rate for an optical network unit which is equal or greater than the minimum data rate.

4. The apparatus of claim 1, wherein said bandwidth provisioning information includes a maximum data rate at which an optical network unit will operate.

5. The apparatus of claim 1, wherein:

the apparatus is connected via one of the upstream optical fiber network and the downstream optical fiber network to an optical line terminal, and

the interface is configured to provide status information for the optical line terminal to the computing device.

6. The apparatus of claim 1, wherein:

the apparatus is connected via one of the upstream optical fiber network and the downstream optical fiber network to an optical line terminal,

the interface is configured to accept settings information, entered by a user using the computing device, for the optical line terminal, and

the interface is configured to transmit the settings information to the optical line terminal.

7. The apparatus of claim 1, wherein:

the apparatus is connected via the downstream optical fiber network to at least a first optical network unit and a second optical network unit, the interface is configured to accept a command, entered by a user using the computing device, to assign the first service level agreement to the first optical network unit and store a related assignment record in the local storage along with an identification of the first optical network unit, and

the interface is configured to accept a command, entered by a user using the computing device, to assign the first service level agreement to the second optical network unit without requiring bandwidth provisioning information in addition to the bandwidth provisioning information stored as the first service level agreement and store a related assignment record in the local storage along with an identification of the second optical network unit.

8. The apparatus of claim 1, wherein:

the interface is configured to accept second bandwidth provisioning information, entered by a user using the computing device, and storing said second bandwidth provisioning information as a second service level agreement in the local storage,

the interface is configured to accept a selection of a service level agreement, entered by a user using the computing device, from among the first service level agreement and the second service level agreement, and

the interface is configured to assign the selected service level agreement to the optical network unit and store a related assignment record in the local storage along with an identification of the optical network unit.

9. The apparatus of claim 1, wherein:

a plurality of service level agreements, including the first service level agreement, are stored in the local storage,

each of the plurality of service level agreements includes weight information,

the apparatus is connected to a plurality of optical network units via the downstream optical fiber network,

the interface is configured to accept a selection of a service level agreement for each of the plurality of optical network units from among the plurality of service level agreements, and

the apparatus is configured to allocate extra bandwidth among the plurality of optical network units based on weight information included in the service level agreement selected for each of the optical network units.