This paper deals with the bandwidth calculation, time slot assignment and average delay analysis in passive optical networks. The basic principle used throughout the time slot allocation for the upstream traffic is provided by the MPCP protocol control messages. The recommendation of this protocol contains both messages used in the upstream and downstream directions. Certainly, various results can be accomplished by different number of users in the network topology. To highlight the discrepancies and possibilities with increased number of optical units, several simulations have been made. During the workflow, we introduce the main topology used for the simulation, how the data transmission is handled in the network and the way the upstream traffic scheduling is completed in. At the end, the traffic utilization is smoothly increased several times to see the differences among various amount of traffic in the system. This work is mainly focusing on the system utilization, delay calculation and the eventual system delay overall.
Słowa kluczowe: delay calculation, TDM-PON, time slot allocation, bandwidth assignment
W artykule analizowane są: pasmo przenoszenia, szczelina czasowa i opóźnienie w pasywnej optycznej sieci. Do alokacji szczeliny czasowej użyto protokołu MPCP. Przeprowadzono symulację zwiększonej liczby użytkowników sieci. Obserwowano sposób przpływu danych w sieci przy wysyłaniu I odbiorze.
Keywords: póżnienie, szczelina czasowa, pasmo, optyczna sieć przesyłowa
During the last couple of years, passive optical networks PON has been identified as one of the most important mile technologies. As a consequence of the solution of passive optical networks, a huge amount of users can benefit from the use of broadband services worldwide. Particular subscribers have an increased demand with regards to the allocated bandwidth in passive optical networks as well. The main reason for that we can see is that there are various services introduced year by year like IPTV, HQ Video Services, etc. In a common structure of a passive optical network, the source traffic is initiated from a unit called as optical line termination OLT. That unit is located mainly in the central office CO and passing thru the data into the optical fiber for a distance of decades in kilometers. The next unit handling this incoming traffic is an optical splitter which is distributing the signal into several optical fibers. The traffic from here is handled towards by a network unit ONT, which is usually deployed next to the customer premises.  The optical signal is terminated here before it will pass over to the users and subscribers. Certainly there are different subscribers with different nature of requirements, therefore the requested time slots as well as the transmission delays within the network topologies are various. To satisfy these needs, the developers have to constantly find new solutions on how to allocate bandwidth. So far, one of the most effective option seems to be to assign the time containers T-CONTs in many various ways. If this is accomplished, the architecture FTTX can still remain attractive to the subscribers. To make this solution competitive with regards to the other available network solutions, the initial cost of this system also has to be kept as low as possible. Passive optical networks PON are now available for many years. There are several standards out there for passive optical networks a [...]
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