We have developed a GMPLS-based software platform with Intelligence Optical Network (ION) capabilities to simulate different technologies and protocols of ASTN. For optical transport network (OTN) based ASTN, usually named as automatically switched optical network (ASON), two signalling schemes, Explicit Label Control (ELC) and Backward Wavelength Reservation with N retries (BWR-N), are considered. The ELC is associated with two routing and wavelength assignment (RWA) policies, the shortest path first routing (Dijkstra algorithm) with first-fit (FF) wavelength assignment and the fixed path least congestion (FPLC) routing with FF wavelength assignment. For the BWR-N, the route is determined by Dijkstra's algorithm and the wavelength is selected through signalling process. For SDH/SONET-based ASTN, we also consider two signalling scheme, the ELC and the Forward Timeslot Reservation (FTR). Similar simulations have been performed. These signalling and routing schemes are evaluated by several crucial metrics, such as the blocking probability, the setup time, the average routing length of the connections and the control overhead. Some significant conclusions have been presented by this paper.
In this paper, a software platform with generalized multi-protocol label switching (GMPLS) -based Intelligence Optical Networks (ION) capacity has been developed as the control plane for the transport network. The survivability was the crucial character of network. This automatic switched transport network (ASTN) simulation platform with the signaling, routing and link management protocols can simulate many survivability mechanisms. Three survivability mechanisms have been simulated as the example. They are 1+1 protection, SPFP and WPB. The results are compared in terms of five performance metrics which are blocking probability (BP), route length (RL), setup time (ST), and Control Overhead (CO). We analyze all the parameters in the article.
In this paper, we introduce that we are developing a software platform with generalized multi-protocol label switching (GMPLS) -based Intelligence Optical Networks (ION) capacity. The survivability was the crucial character of optical transport network. The optical network is transmitting from static transport network to a more dynamic, flexible network. So the intelligent optical network (ION) has been proposed. IUT-T standardizes the automatically switched optical network (ASON) on G.8080 which defines the architecture. The ASON simulation software platform is based on GMPLS. The protection and restoration mechanisms specified in the next. Our simulation architecture is illustrated and the recovery time is analyzed.
In this paper, we propose four different RWA schemes which are introduced into the wavelength-routed intelligent optical networks. FSP+FF and FPLC+FF are traditional RWA schemes used in the centralized control environment. The other two schemes, FWR-4 and BWR-3, are distributed wavelength reservation protocols which invoke the GMPLS REVP-TE. These schemes are emulated in GMPLS-based NSFNET. The results are compared in terms of four performance metrics which are blocking probability (BP), route length (RL), setup time (ST) and control overhead (CO). Except for FWR-4, the BPs of the other three RWA schemes are similar, and in the case of lighter traffic load the BP of FPLC+FF is the smallest, but under heavier traffic load the BP of BWR-3 is the best. Because FPLC+FF does not always choose the shortest path compared with other RWA schemes using the shortest path routing algorithm, so its RL is the longest. The route and wavelength are determined by the source node, and the RL is shorter, therefore the lightpath setup in FSP+FF is the fastest among all schemes. In addition, the CO of FWR-4 is the fewest because it need not flood the routing information and retry. Though the four schemes respectively have their advantages, the performance of BWR-3 is outstanding among them if its ST can be accepted.
In this paper, according to the ITU-T recommendation G.8080, we present a novel architecture of RC based on the extended GMPLS, which consists of interface component, OSPF-TE component, route computation component and routing information database. The RC is emulated in the ASON simulation software developed by us, where the OSPF is extended as the routing protocol and GMPLS RSVP-TE is adopted as signalling protocol. In the simulation, the RWA scheme, the fixed shortest path routing way and first fit wavelength algorithm, is used. The simulation results of RC have been presented in terms of flooding time (FT), flooding overhead (FO) and route computing time. The FT and FO just have a very little change under different traffic load, which indicates that re-flooding is rare and the RC works efficiently.