Internet Engineering Task Force G. Martinelli, Ed. Internet-Draft G. Galimberti Intended status: Informational Cisco Expires: January 5, 2012 July 4, 2011 WSON Optical Interface Class draft-martinelli-wson-interface-class-00 Abstract Current work on wavelength switched optical network includes several considerations regarding the interface signal compatibility. In particular ingress and egress optical interfaces will require a check on several optical parameters to assess if the signal generated by the ingress interface can be compatible with the receiving interface. Current solution available encode all parameters in WSON protocol extensions while in this draft will propose an alternative method to keep into account the signal compatibility issue at protocol level. 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). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on January 5, 2012. Copyright Notice Copyright (c) 2011 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 Martinelli & Galimberti Expires January 5, 2012 [Page 1] Internet-Draft WSON Optical Interface Class July 2011 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 3 2. Existing WSON Signal Compatibility protocol extension . . . . . 3 3. Optical Interface Class . . . . . . . . . . . . . . . . . . . . 4 3.1. Concept and Procedures . . . . . . . . . . . . . . . . . . 4 3.2. Encoding . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Optical Interface Class Semantic . . . . . . . . . . . . . . . 6 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . . 8 Appendix A. Encoding example . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Martinelli & Galimberti Expires January 5, 2012 [Page 2] Internet-Draft WSON Optical Interface Class July 2011 1. Introduction The current work on Wavelength Switched Optical Network (WSON) define the need of assessing the signal compatibility during the routing and wavelength assignment (RWA) process. In details, the [RFC6163] reports the ingress and egress interfaces and the regeneration points as places where the optical signal compatibility must be assured. Regarding how to evaluate, there are a list of parameters identified according to ITU specification [ITU-G.698.1] and [ITU-G.698.2]. In particular the following set of parameters has been chosen: signal bit rate, modulation format, forward error correction. At the current state of art new high bit rates (40G/100G) are under development as well as new modulation formats and it is not clear if and when there will be a dominating technology. In a current realistic scenario DWDM optical networks manage different bit-rates as well as different modulation formats over the same link. So in general different signal characteristics will coexist at the same time. To a further extent, the WSON activity will consider the case where the control plane has optical impairments awareness as detailed in [I-D.ietf-ccamp-wson-impairments]. The Control Plane function related to impairment awareness might require some additional interface parameters to assess the optical feasibility path. In such a case is likely further protocol extensions might be required just to add some parameters. Scope of this draft is to propose an Optical Interface Class identifier as a solution for the WSON signal compatibility problem. To some extend the idea is have protocol extensions independent from optical technology evolution by keeping the semantic of optical characteristics separated from protocol scope. The final goal is a simplified but general representation rather than encoding saving. 1.1. Requirements Language 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]. 2. Existing WSON Signal Compatibility protocol extension Within the current WSON activity the signal compatibility encoding is defined within the [I-D.ietf-ccamp-rwa-wson-encode]. In details, the following list of parameters is considered: Martinelli & Galimberti Expires January 5, 2012 [Page 3] Internet-Draft WSON Optical Interface Class July 2011 o Modulation Format. Only NRZ currently defined. o FEC, according to G.709 and G.975. o Bit Rate. Note that this list of parameters is defined by ITU and might be subject to change due to internal physics. The above encoding is going to be used within several WSON specific protocol extensions. o OSPF [I-D.ietf-ccamp-wson-signal-compatibility-ospf] since the path computation function need to consider optical interface parameters during the RWA process. o RSVP [I-D.ietf-ccamp-wson-signaling] since during the signaling phase there is the need to know optical ingress and egress interface properties (and eventually interfaces at regeneration point). o In addition, PCEP extension might need similar parameters as envisaged here [I-D.lee-pce-wson-rwa-ext]. In case of any update from ITU standards regarding optical signals and interfaces all the above drafts making use of the same information needs an update. 3. Optical Interface Class 3.1. Concept and Procedures The Optical Interface Class will be a unique number that identify all information related to optical characteristic's of such interface. In term of RWA process the only operation required to assess the endpoint compatibility (interfaces or regeneration points) is to check if the two LSP endpoint have the same Class value. The procedure of signal compatibility assessment become just a numbers comparison: if two Optical Interface Class are equals the signal compatibility constrain is satisfied. Martinelli & Galimberti Expires January 5, 2012 [Page 4] Internet-Draft WSON Optical Interface Class July 2011 +---+ +----+ +----+ +-----+ +----+ +---+ | I |----| N1 |---| N2 |-----| REG |-----| N3 |----| E | +---+ +----+ +----+ +-----+ +----+ +---+ class1 class1 class2 class2 |<----------------------------->|<-------------------->| LSP |<---------------------------------------------------->| Figure 1 In case the RWA process will result in a path that need a wavelength conversion each interface involved in the wavelength conversion must satisfy the Optical Interface Class constrain. As represented in Figure 1, two different Optical Interface Classes are required for the given LSPs. By using the Optical Interface Class concept every protocol extensions supporting WSON does not need to care about DWDM signal details and does not need to consider technology specific evolution. If a new parameter values are standardized (e.g. new modulation formats become standard) the wson protocols and RWA don't need any extensions. 3.2. Encoding 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optical Interface Class | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Optical Interface Class The Optical Interface Class will be used in proper TLVs for different WSON protocol extensions . In case an optical interface or a regeneration point will support multiple capabilities, a list of Interface Classes can be used as defined in [I-D.ietf-ccamp-rwa-wson-encode]. [Editor Note: the number could be 32 or 64 bits, size to be defined.] Martinelli & Galimberti Expires January 5, 2012 [Page 5] Internet-Draft WSON Optical Interface Class July 2011 4. Optical Interface Class Semantic The semantic of the Optical Interface Class must be defined outside the control plane but it must be unique for all control plane elements. In this way the same class value will have the same meaning on every network node. Within this hypothesis, we need to solve the problem on how to make any network element aware of the semantic behind the Optical Interface Class and make sure it can figure out the right value for its interfaces. An example of semantic is the "Application Code" within [ITU-G.698.1] and [ITU-G.698.2]. The Application Code could be easily represented by a number represented by the Optical Interface Class. This number might be used as an index to access a table containing all the values associated with a specific interface using mechanisms like Directory Services. Note that each single interface parameter could be retrieved through a MIB. As an example, [draft-galimbe-kunze-g698-2-snmp-mib] gives another example on the Optical parameter specification includes the OII definition in compliance with [ITU-G.698.2] Chapter 5.3. Every time a new optical interface is defined or introduced into the market, only a MIB update will be required but there will be no impact on WSON protocols. Note also that the Control Plane may become aware of the Optical Interface Class semantic by a various of other ways like the network management system or manual provisioning. As a matter of fact in current WSON technology, standard and proprietary information must co-exist. The introduction of the Optical Interface Class does not change or limit this possibility since the class identifier can be a means to access either public or vendor specific information. In term of protocol encoding however, this solution has the advantage to limit eventually proprietary information in a fixed size field. 5. Acknowledgements 6. IANA Considerations This memo includes no request to IANA. All drafts are required to have an IANA considerations section (see the update of RFC 2434 [I-D.narten-iana-considerations-rfc2434bis] for a guide). If the draft does not require IANA to do anything, the Martinelli & Galimberti Expires January 5, 2012 [Page 6] Internet-Draft WSON Optical Interface Class July 2011 section contains an explicit statement that this is the case (as above). If there are no requirements for IANA, the section will be removed during conversion into an RFC by the RFC Editor. 7. Security Considerations All drafts are required to have a security considerations section. See RFC 3552 [RFC3552] for a guide. 8. References 8.1. Normative References [I-D.ietf-ccamp-rwa-wson-encode] Bernstein, G., Lee, Y., Li, D., Imajuku, W., and J. Han, "Routing and Wavelength Assignment Information Encoding for Wavelength Switched Optical Networks", draft-ietf-ccamp-rwa-wson-encode-11 (work in progress), March 2011. [I-D.ietf-ccamp-wson-signal-compatibility-ospf] Lee, Y. and G. Bernstein, "OSPF Enhancement for Signal and Network Element Compatibility for Wavelength Switched Optical Networks", draft-ietf-ccamp-wson-signal-compatibility-ospf-04 (work in progress), March 2011. [I-D.ietf-ccamp-wson-signaling] Bernstein, G., "Signaling Extensions for Wavelength Switched Optical Networks", draft-ietf-ccamp-wson-signaling-01 (work in progress), March 2011. [ITU-G.698.1] International Telecommunications Union, "Multichannel DWDM applications with single-channel optical interfaces", ITU- T Recommendation G.698.1, December 2006. [ITU-G.698.2] International Telecommunications Union, "Amplified multichannel DWDM applications with single channel optical interfaces", ITU-T Recommendation G.698.2, July 2007. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Martinelli & Galimberti Expires January 5, 2012 [Page 7] Internet-Draft WSON Optical Interface Class July 2011 8.2. Informative References [I-D.ietf-ccamp-wson-impairments] Lee, Y., Bernstein, G., Li, D., Martinelli, G., Chen, M., Han, J., Galimberti, G., Tanzi, A., Bianchi, D., Kattan, M., Schroetter, D., Ceccarelli, D., Bellagamba, E., and D. Caviglia, "A Framework for the Control of Wavelength Switched Optical Networks (WSON) with Impairments", draft-ietf-ccamp-wson-impairments-07 (work in progress), April 2011. [I-D.lee-pce-wson-rwa-ext] Lee, Y., Casellas, R., Margaria, C., and O. Dios, "PCEP Extension for WSON Routing and Wavelength Assignment", draft-lee-pce-wson-rwa-ext-01 (work in progress), March 2011. [I-D.narten-iana-considerations-rfc2434bis] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", draft-narten-iana-considerations-rfc2434bis-09 (work in progress), March 2008. [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June 1999. [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC Text on Security Considerations", BCP 72, RFC 3552, July 2003. [RFC6163] Lee, Y., Bernstein, G., and W. Imajuku, "Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)", RFC 6163, April 2011. Appendix A. Encoding example In this section we try to represent how the encoding will change considering the Optical Interface Class. The main result of the Optical interface class will be not encoding saving in term of bytes but a simplified support for new optical technologies. Martinelli & Galimberti Expires January 5, 2012 [Page 8] Internet-Draft WSON Optical Interface Class July 2011 Authors' Addresses Giovanni Martinelli (editor) Cisco via Philips 12 Monza 20900 IT Phone: +39 039 209 2044 Email: giomarti@cisco.com Gabriele M Galimberti Cisco Via Philips,12 20052 - Monza Italy Phone: +390392091462 Email: ggalimbe@cisco.com Martinelli & Galimberti Expires January 5, 2012 [Page 9]