Network Management Architecture for Robust Packet Routing in Optical Access Networks

摘要

We describe an architecture for optical local area network (LAN) or metropolitan area network (MAN) access. The architecture allows for bandwidth sharing within a wavelength and is robust to both link and node failures. The architecture can be utilized with an arbitrary, link-redundant mesh network 'node-redundancy is necessary only to handle all node failures', and assumes neither the use of a star topology nor the ability to embed such a topology within the physical mesh. Reservation of bandwidth is performed in a centralized fashion at a 'replicated' head end node, simplifying the implementation of complex sharing policies relative to implementation on a distributed set of routers. Unlike a router, however, the head end does not take any action on individual packets and, in particular, does not buffer packets. The architecture thus avoids the difficulties of processing packets in the optical domain while allowing for packetized shared access of wavelengths. In this paper, we describe the route construction scheme and prove its ability to recover from single link and single node failures, outline a flexible medium access protocol and discuss the implications for implementing specific policies, and propose a simple implementation of the recovery protocol in terms of state machines for per-link devices.