Networking Group S. Yin Internet Draft Sh.G. Huang Intended status: Informational BUPT Expires: November 2019 S. Zhou X.K. Meng R. Ma BUPT May 23, 2019 Optimization of RWA Problem through OSNR draft-yin-rwa-osnr-03 Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on November 23, 2019. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Huang, et al. Expires November 23, 2019 [Page 1] Internet-Draft rwa-osnr Problem May 2019 Legal Provisions and are provided without warranty as described in the Simplified BSD License. Abstract This documentary provides a kind of routing optimization method. In the basic of RWA solution method, both the output power of the route and the OSNR value of the optical signal noise ratio are considered. The selected optimal route has a lower bit error rate and the whole communication network performance is improved. Table of Contents 1. Introduction ................................................ 2 1.1. Terminology ............................................ 3 2. Conventions used in document ................................. 3 3. Overview ....................................... 4 3.1. RWA Problem ............................................ 4 4. Calculation formula ......................................... 4 5. Optimization of RWA problem through OSNR .................... 5 6. Formal Syntax ............................................... 6 7. Security Considerations .................................. 6 8. IANA Considerations ......................................... 6 9. Conclusions ................................................. 7 10. References ................................................. 7 10.1. Normative References ............................. 7 10.2. Informative References ......................... 7 11. Acknowledgments ............................................ 7 1. Introduction RWA is one of the core issues in the optimization of network performance. Currently, due to a variety of physical and technical constraints, optical network cannot provide all the required physical properties, thus the study and solution of the problem plays a vital role to optimize the network and improve the utilization rate of cyber source. The Routing and Wavelength Assignment (RWA) is one of the key problems of the optimization of network performance. At present, the RWA problem is usually solved by being decomposed into the routing sub problem and wavelength assignment problems. Huang, et al. Expires November 23, 2019 [Page 2] Internet-Draft rwa-osnr Problem May 2019 However, in the existing solutions of RWA, the allocation of routing and wavelength only considers the network performance such as network throughput, required wavelength, optical fiber number and optical path blocking rate, while the output power and the Optical Signal Noise Ratio (OSNR) index after establishing optical path are not considered. In the long distance transmission of the optical transport network (OTN), the output power and optical signal-to-noise ratio (OSNR) of optical path will seriously affect the BER of communication system, so that the routing based on RWA algorithm is not the best, which impacts the overall network performance of communication system. So this method has taken a comprehensive consideration of the channel output power POUT and the OSNR performance in the existing RWA solution, in order to achieve the optimizing routing. 1.1. Terminology RWA: Routing and Wavelength Assignment. Wavelength Conversion: The process of converting an information bearing optical signal centered at a given wavelength to one with "equivalent" content centered at a different wavelength. Wavelength conversion can be implemented via an optical-electronic-optical (OEO) process or via a strictly optical process. OTN: Optical Transport Networks. OSNR: Optical Signal Noise Ratio OLA: Optical Line Amplifier ASE: Amplifier spontaneous emission noise 2. 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 [RFC2119]. Huang, et al. Expires November 23, 2019 [Page 3] Internet-Draft rwa-osnr Problem May 2019 3. Overview In dynamic optical transport network, research on the resource optimization and constraint-based routing problem mainly includes the following aspects: (1)path selection and wavelength assignment problem in optical layer. (2)Constraint-based routing problem under dynamic business in Multi- layer network. (3)resource optimization problem under dynamic business in the multi- layer network. 3.1. RWA Problem Optical layer path selection and wavelength assignment problem, which is called RWA (Routing and Wavelength Assignment, routing and wavelength assignment) problem, is mainly caused by the require of consistency and constraints of wavelength in the optical fiber link. Optical layer routing based on Dijkstra algorithm is usually started with the different parameters which are chosen refer to the least costly path. Common optical path selection algorithms contain mainly fixed routing algorithm, fixed alternate routing algorithm, adaptive routing algorithm and adaptive shortest alternate routing algorithm. Wavelength assignment algorithm is usually based on heuristic algorithms, aiming to obtain the minimum blocking rate under a certain number of wavelengths. There are several common wavelength assignment algorithms such as randomly assigned wavelength method, first-fit, the minimum application method, the most widely used method and the lightest load method. The core problem of dynamic business constraints routing issue is how to combine electrical and optical layers to find proper routes. 4. Calculation formula There are three important formula in this documentary. (1) Output power formula P_out=P_in+SUM[Gi-Li];0