Research Of Dynamic Bandwidth Allocation Applied In Metro Networks

With the rapid increase of IP-based traffic, such as peer-to-peer (P2P) application, video conference, IPTV and so on, MSTP (Multi-Service Transport Platform) which is one of the main technologies in the metro networks and based on Ethernet over SDH (EOS) technology to transport IP traffic is challenged to adapt to this change. MSTP adopts static bandwidth configuration and lacks statistical multiplexing, data services processing and convergence capabilities. Passive optical network (PON) is being the first choice in wide band access network. Dynamic bandwidth allocation in PONs presents a key issue for providing efficient and fair utilization of the PON upstream bandwidth while supporting the QoS requirements of different traffic classes. So a new technology named GTH(GPON-based transport hierarchy) was purposed by Huawei cooperation which applied the idea of DBA in PONs to the metro network to solve the problems MSTP facing. The GTH technology was elaborated carefully in the paper. A simulation platform has been constructed in order to analyze the advantages and disadvantages of GTH compared with MSTP and PTN technologies. The simulation results showed that with DBA mechanism applied GTH utilized the network bandwidth better than the other two technologies. As to the packet loss ratio parameter, GTH has better performance too, especially when the network load become heavier. The service delay of GTH was a little higher than MSTP, as it cost time to execute the DBA algorithm and inform the results to the other nodes. But it was lower than that of PTN when the network load was heavy. At the mean time the OAM performance and network survivability of GTH were as better as MSTP. These results prove that GTH can be largely deployed in the metro network to bear the packet based services perfectly.