IP over Optical Networks: A Summary of Issues

This draft presents a summary of issues related to transmission of IP packets over optical networks. This is a compilation of many drafts presented so far in IETF. The goal is to create a common document, which by including all the views and proposals will serve as a better reference point for further discussion. The novelty of this draft is that we try to cover all the main areas of integration and deployment of IP and optical networks including architecture, routing, signaling, management, and survivability. IP over Optical Networks: Summary of Issues July 2000 Many Authors Informational Expires January 2001 Page 2 of 52 Several existing and proposed network architectures are discussed. The two-layer model, which aims at a tighter integration between IP and optical layers, offers a series of important advantages over the current multi-layer architecture. The benefits include more flexibility in handling higher capacity networks, better network scalability, more efficient operations and better traffic engineering. Multiprotocol Label Switching (MPLS) has been proposed as the integrating structure between IP and optical layers. Routing in the non-optical and optical parts of the hybrid IP network needs to be coordinated. Several models have been proposed including overlay, augmented, and peer-to-peer models. These models and the required enhancements to IP routing protocols, such as, OSPF and IS-IS are provided. Control in the IP over Optical networks is facilitated by MPLS control plane. Each node consists of an integrated IP router and optical layer crossconnect (OLXC). The interaction between the router and OLXC layers is defined. Signaling among various nodes is achieved using CR-LDP and RSVP protocols. The management functionality in optical networks is still being developed. The issues of link initialization and performance monitoring are summarized in this document. With the introduction of IP in telecommunications networks, there is tremendous focus on reliability and availability of the new IPoptical hybrid infrastructures. Automated establishment and restoration of end to end paths in such networks require standardized signaling and routing mechanisms. Layering models that facilitate fault restoration are discussed. A better integration between IP and optical will provide opportunities to implement a better fault restoration. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119.