The Implementation Of RIP In The OLT Of GPON

As networks tend to be flattened, a direction has been pointed out bytelecommunication operators that Optical Line Terminals (OLTs) of Gigabit-CapablePassive Optical Network (GPON) should become aggregation OLTs, which enables themto work as both aggregation switches and edge-access-devices. According to thisrequirement, a solution that realizes Routing Information Protocol (RIP) on OLTs ofGPON is issued after deep analyses of GPON system and RIP. As a result, the IP routingon OLTs of GPON is realized, which allows OLTs to work on the network layer.Additionally, the broadband network levels are simplified, the cost of construction andmaintenance are reduced, and the reliability of the network is increased.This paper includes a deep study of the GPON system to understand the hardwareand software framework. Also, the mechanism of conventional OLT is analyzed todemonstrate its disadvantages. Ultimately, considering the tendency of telecommunicationnetworks, the implementation of IP routing on GPON system is proposed. Since RIP is thebasic dynamic routing protocol, an approach that enables RIP on the OLTs is designed afterthe thorough study of the RIP standards. Firstly, the software architecture of aggregationOLTs is implemented, which involves the realization of L3interface, driver and RouteManage Module (RTM). This implementation lays a solid foundation for the realization ofRIP module. On one hand, it establishes the channel for sending and receiving RIP packets;on the other, it ensures the management of RIP routing entry. Secondly, for the purpose ofgeneral design, the RIP module is divided into six submodules according to their functions.The internal and external interfaces as well as the major implementing process aredesigned for each submodule. The software that applies RIP on OLTs of GPON isdeveloped on Vxworks. Moreover, The test cases is designed based on standards of RIP，and the function is tested carefully in the laboratory. The result of experiment shows that IProuting can be implemented on OLT, and packets can be correctly processed and forwardedon the network layer. Furthermore, it can work with the Cisco switch in the real network.