Rothkegel, Walter; Schneider, Matthias (Lucent Technologies Network Systems GmbH, Thurn-und-Taxis-Str. 10-14, 90411 Nürnberg, Germany)
Neighbor Discovery is a service that may be utilized in ASON/GMPLS based networks to derive and verify transport neighbor relationships with as little manual interaction as possible from the current node configuration. These relationships are then used by services like signaling or routing in order to establish transport connections, support protection switching and path restoration, or automate the inventory process of network operators Various aspects of neighbor discovery within a single transport layer have been addressed by standards of the ITU-T (International Telecommunications Union), the IETF (Internet Engineering Task Force) and the OIF (Optical Internetworking Forum). This work focuses on multi-layer aspects of neighbor discovery, taking into account requirements of different technologies and looking at the interdependencies between multiple transport layers such as Synchronous Digital Hierarchy (SDH)/Synchronous Optical Network (SONET) and Optical Transport Network (OTN). Especially when a server layer is not fixed and provides flexibility or multiple adaptations into the client layer, neighbor discovery in the client layer can become a rather dynamic process. Finally this work investigates neighbor discovery aspects for different interface types like User-to-Network Interface (UNI), the External Network-to-Network Interface (E-NNI) and the Internal Network-to-Network Interface (I-NNI).