With the aim of widening ONTs offer, it is important that any OLT interoperates with all available ONUs in the market. However, GPON has a number of intrinsic characteristics that is currently making difficult to achieve the desired level of the interoperability:
- Coexistence of products with different standard versions.
- Problems during the activation process.
- Different ways of implementing the standards.
- OMCI, a very broad and with “vendor specific” options.
- Heterogeneity among operators.
Furthermore, the structure of a PON network is a fibre that is further divided using optical power splitters. The “degree of splitting”, defined as the number of divisions that the fibre goes through before reaching an ONT, determines the percentage of optical power arriving to that ONT. Attenuation in a GPON circuit can be very high due to the sum of fibre splitting, connectorization (Insertion loss), fusion splice, and distance in the fibre, and thus, some of the network active elements may be operating under stress conditions.
In order to reach the optimum performance state of a GPON network , during the deployment and maintenance, all causes of interference need to be debugged by tools like GPONDoctor 2000.
Once a Network is deployed, it is required that the usage of a test tool does not impact in its behaviour. Therefore, GPON-Doctor™ 2000 transparently sniffs traffic within a FTTH network. Moreover, its automatic calibration and stand alone configuration enables full capture of GPON network traffic without disturbing the communication between the OLT and ONTs.
The capture can be very long (e.g. 30 minutes) and allows captured data export to XML format for later analysis in desktop computers.
The smart analysis software interprets the captured data and translates it into a graphical and categorized format that can be easilyused for in-depth analysis of GPON protocol conformance, interoperability evaluation, bandwidth assignments and field deployment troubleshooting.
The results from the GPON Doctor™ analysis show:
- GPON network topology: ONTs detected, ONTs and OLT operational status, data channels established,
- Entities created and the relationship among them,
- Bandwidth assignment graphics per ONT and TCONT,
- Degree of standard conformance, by applying an evaluation smart engine, based on contextualized dynamic rules, against the ITU-T G.984.x protocol .
GPON-Doctor™ 2000 allows clear-text user traffic extraction in real-time for both upstream and downstream. The traffic is extracted at Ethernet layer.
This traffic can be further analysed by upper layer protocol analyzers, either external or by a software network protocol analyzer installed within the host PC/Laptop.
The combination of the GPON Doctor™ 2000 with a traffic generator and GPON OLT emulator, like GPON-Doctor™ OLT-e, is a powerful setup to verify the correct ONTs behaviour over a GPON network.
This feature can be also used to regenerate services inside GPON Doctor™: Play Multicast Video flows, hear sound of voice services in realtime, analyze QoS & QoE.