Creation of a broadband network based on gpon technology qualification work of bachelor

Main advantages
 Fast connection of subscribers with the provision of any modern communication services via optics and IP;
 Seamless integration in access networks and traffic aggregation on ZyXEL equipment;
 Full compliance with EFM, IEEE 802.3 ah standards;
 Support for multicast and 802.1 Q VLANs, flexible means of prioritizing traffic at the GEPON port level;
 Гибкие Flexible management tools, including RS-232 and 10/100Base-TX ports for secure off-network management and network monitoring.

Specifications

 8 GEPON interfaces (SC-type connector), with support for up to 32 ONUs on each port
 Wavelength: 1.31 for upstream channel & 1.55 for downstream channel
 8 1000Base-T ports
 1 10 / 100Base-T port for management
 1 DB9 RS-232 port for console connection
Optical power budget
For ONU at 10km - at least 29dB
Performance
 Upstream/Downstream: 1.25/1.25 Gbps
Physical parameters
 Dimensions: 440 (W) x 443 (D) x 43.6 (H) mm
 Weight: 4.7 Kg
Environmental parameters
 Temperature: 0°C ~ 50°C
 Humidity: 5% ~ 90% (non-condensing)
Power Supply Parameters
 Voltage: ~ 220V В
Passive equipment ONU is installed in the subscriber's apartment.

Picture 4. 15-ZyXEL ONU-631HA

Main advantages

 High transfer speed and secure connection (IEEE 802.1 x authorization);
 Full compliance with EFM IEEE 802.3 ah standards;
 Easy integration into the network infrastructure;
 Two models at a range of 10 and 20 km to reduce the cost of building a network;
 Centralized management and firmware updates do not require user configuration;
 Support for all algorithms required for traffic management (802.1 p / Q, IGMP multicast filtering, etc.) and reliable provision of modern communication services.

Specifications:

 One GEPON port, SC connector
 One 100/1000 Base-T port
 Working distance: ONU-631HA-11-10 km, ONU-631HA-12-20 km
Network Features
 802.1 Q VLAN support
 802.1 p support
 802.1 x support
 MAC address filtering
Management features
 External OAM control
Basic parameters
Dimensions, mm 188x120x30
 Weight, g 405
Environmental parameters
 Temperature: 0 ~ 50°C
 Humidity: less than 95% (non-condensing)
Power Supply Parameters
 Voltage: ~ 220V
 Power consumption: 8W.
 External 12B DC adapter
3.5. Principles of configuring a PON network
Real attenuation in the optical line between the central node and the subscriber device (active or preparing for connection).
Location of the problem area, if the actual attenuation in the line was higher than expected (calculated or reference).
To answer the first question, it is enough to make simple measurements using an optical tester. The second question is more complex and requires the use of an optical reflectometer (OTDR), as well as some experience in decoding reflectograms.
As a general rule, it is desirable that all necessary measurements can be performed on a working PON network without disconnecting subscribers (except, possibly, the one being tested). Such testing is carried out at a non-working wavelength using additional devices (DWDM wave multiplexers, filters) so that the radiation of the measuring equipment does not interfere with the useful signal. As already mentioned, in the PON network, the forward channel (from the center to subscribers) uses a wavelength of 1490 or 1550 nm (for video), for the reverse channel - 1310 nm. For testing a PON network, a wavelength of 1625 nm is usually used.
Radiation from measuring equipment (tester, reflectometer) is introduced into the fiber immediately after OLT using a wave multiplexer (DWDM). This radiation can cause interference to the optical receiver of the subscriber device, so a filter must be installed before each ONT subscriber device. In order to be able to perform testing without disconnecting the network, the wave multiplexer and filters must be permanently connected to the optical path.

Picture 4.1-Connection diagram of the wave multiplexer and filters to the PON
A 1625 nm optical tester is used to measure the attenuation in the optical line between the OLT and ONT нм. The tester's transmitter is connected to the free end of the wave multiplexer on the OLT.


Picture 4.2 - Measurement of attenuation when the subscriber device is disconnected

You can also measure attenuation without disconnecting the subscriber's device. To do this, the ONT does not need to use a filter, but a wave multiplexer, as in the central node.

Picture 4.3 - Taking a reflectogram of the PON tree.
The method of testing the PON network using a reflectometer is as follows. After each change in the network topology (connection of a new subscriber, replacement of the splitter, etc.), a reference (reference) reflectogram is removed, which corresponds to the normal state of the network. If problems are detected in the network (for example, if the attenuation measured by the optical tester is higher than the calculated one), a new reflectogramis taken and compared with the reference one. New events on the reflectogram localize the location of the problem area.


Picture 4.4 - Analysis of new events on the reflectogram
Using the reflectometer, you can monitor the PON network and detect fiber degradation before problems occur. To do this, you need to regularly (for example, once a week) take рефлектограммуa network reflectogram and compare it with the reference reflectogram. If any deviations and especially new events appear on the reflectogram, it is necessary to analyze their possible causes and, if necessary, carry out adequate preventive measures.
3.6. Next-generation PON
vices are such that in a few years the characteristics of current PON technologies may not meet the requirements of operators. Therefore, leading manufacturers, together with operators, are actively engaged in the development and pilot implementation of the next - generation PON systems-NG-PON.
The main goals of NG-PON are to increase the bit rate, range, and number of users that NG-PON can serve. Migration issues from existing gpons or IEEE epons to such NG-pons are also addressed.
GPON To meet the growing appetite for increased bandwidth, the current 2.5 GPON systems will be upgraded to support 10 Gbit /s downstream. Such systems will be able to simultaneously transmit more than a thousand HDTV streams with very fast channel switching times due to the broadcast nature of PON. The entire set of unicast personalized services will also be supported.
The first 10G GPON systems will have an upstream speed of 2.5 Gbps. 10G GPON systems will co-exist with already deployed GPON in a single optical distribution network. "Coexistence" is achieved by placing 10G GPON systems at other (non-GPON) wavelengths. 10G GOPN will use low-cost optical components with the same optical budget as GPON. The use of low-cost components is especially important for ONTs (due to their large number on the network).
GEPON technology is a subgroup of modern, promising fiber-based broadband technologies. A distinctive feature of all PON technologies (passive optical networks) is that the entire distribution network is built exclusively on passive components: in a single-fiber line, signal propagation is carried out on special optical power splitters, the so-called splitters. Passive optical networks GEPON are organized on the basis of three components: OLT - station terminals, splitters and ONT - subscriber terminals. Station terminals are used to organize connection to external data transmission networks, subscriber terminals are used to provide services on the subscriber side.
GEPON networks have a point-to-multipoint topology, branched tree segments are connected to one port of the central node. Signal splitting and splitting is performed using power and maintenance-free splitters. Thus, multiple ONT subscriber units receive data from one transceiver module in the station terminal. GEPON technology is one of the subclasses of PON networks that provide the highest data transfer rates (up to 1.2 Gbps). It is GEPON technology that allows optimal use of optical fiber resources. Only one fiber optic segment is required to connect 64 subscribers within a radius of 20 km.
Advantages of GEPON technology The prospect of reducing equipment costs thanks to standard 802.3ah mechanisms Transfer rates up to 1 Gbps in both directions.QoS using 802.1p / TOS. Quality assurance for VoIP or VoD services. Connection of up to 64 subscribers via one optical fiber. Streaming video transmission (IGMP Snooping).
Similarly, the next step in the development of EPON is the creation of 10G EPON. The standard for the new 10G EPON is IEEE 802.3 av, which is expected in late 2009. It will include support for symmetric down and upstream speeds of 10 Gbpsс and will be compatible with 802.3 ah EPON.
Meanwhile, leading hardware vendors have already announced their 10G GPON and 10G EPONprototypes.PON
The cutting edge of PON development and the long - term future of PON is WDM-PON, which uses a DWDM wave grid to place a large number of parallel high-speed channels on top of a single PON structure. WDM-PON offers an alternative to the time-division transmission scheme as in GPON, a scheme where each ONT transmits and receives data at a specific wavelength. A typical WDM-PON architecture will replace passive splitters with wave selective filters, which are often implemented as an Arrayed Waveguide Grating (AWG ) Grating. Main advantages of WDM-PON:
-the user is provided with a dedicated lane (there is no competitive allocation).);
-subscriber signals are physically isolated;
-efficient use of fiber (up to 64 subscribers per fiber, as in GPON);
-a significant increase in the communication range is possible (using AWG with low losses instead of inefficient splitters in terms of losses with a standard GPON budget of 28 dB, you can connect subscribers at a distance of about 80 km).
The main disadvantage of WDM-PON is its high cost, since it requires narrow-band transmitters that emit at a given wavelength. This is especially critical for ONT subscriber devices, as their cost directly affects the cost of the subscriber line. On the one hand, the problem is partially solved by unifying and reducing the types of hardware components in terminal devices (for example, using lasers tuned to a given wavelength), on the other hand, it is not without reason that we can hope that in a few years by the time the standard is released, the cost of optical components for WDM-PON will be significantly lower than
The first WDM-PON products are already starting to appear, but essentially now this technology is being built from the "pieces" put together and is under development - the architecture and parts of the system as a whole are defined, but the need to fill in the gaps and bring these parts together still existsпор. увеличенной дальностью
Many operators are considering consolidating their points of presence to reduce the operational costs of the access network. Thus, the extended-range GPON offer will allow you to increase the area served by the operator from a single point, and eliminate intermediate station points of presence. Potentially, the number of ONTs per OLT will also increase. We are talking about the size of the access network, estimated in tens of kilometers.
Thus, solutions based on the use of optical amplifiers to increase the optical budget can achieve a range of 60 km.