Network Working Group Y. Lee Internet Draft Huawei Intended status: Standards Track G. Bernstein Expires: February 2016 Grotto Networking August 28, 2015 GMPLS OSPF Enhancement for Signal and Network Element Compatibility for Wavelength Switched Optical Networks draft-ietf-ccamp-wson-signal-compatibility-ospf-17.txt Status of this Memo This Internet-Draft is submitted to IETF 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." 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Code Components extracted from this document must 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. Abstract This document provides Generalized Multiprotocol Label Switching (GMPLS) Open Shortest Path First (OSPF) routing enhancements to support signal compatibility constraints associated with Wavelength- Switched Optical network (WSON) elements. These routing enhancements are applicable in common optical or hybrid electro-optical networks where not all of the optical signals in the network are compatible with all network elements participating in the network. This compatibility constraint model is applicable to common optical or hybrid electro optical systems such as Optical-Electronic-Optical (OEO) switches, regenerators, and wavelength converters since such systems can be limited to processing only certain types of WSON signals. 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 [RFC2119]. Table of Contents 1. Introduction...................................................3 2. The Optical Node Property TLV..................................3 2.1. Resource Block Information................................5 2.2. Resource Accessibility....................................5 2.3. Resource Wavelength Constraints...........................5 2.4. Resource Block Pool State.................................5 2.5. Resource Block Shared Access Wavelength Availability......5 3. Interface Switching Capability Descriptor (ISCD) Format Extensions........................................................5 3.1. Switching Capability Specific Information.................6 4. WSON Specific Scalability and Timeliness.......................7 5. Security Considerations........................................8 6. IANA Considerations............................................9 Lee and Bernstein Expires November 2014 [Page 2] Internet-Draft OSPF Enhancement for WSON August 2015 6.1. Optical Node Property TLV.................................9 6.1.1. Optical Node Property Sub-TLV........................9 6.2. WSON-LSC Switching Type TLV..............................10 6.2.1. WSON-LSC SCSI Sub-TLVs..............................10 7. References....................................................11 7.1. Normative References.....................................11 7.2. Informative References...................................11 8. Authors' Addresses............................................12 1. Introduction The documents [RFC6163, RFC7446, RFC7581] explain how to extend the Wavelength Switched Optical Network (WSON) control plane to support both multiple WSON signal types and common hybrid electro optical systems as well hybrid systems containing optical switching and electro-optical resources. In WSON, not all of the optical signals in the network are compatible with all network elements participating in the network. Therefore, signal compatibility is an important constraint in path computation in a WSON. This document provides GMPLS OSPF routing enhancements to support signal compatibility constraints associated with general WSON network elements. These routing enhancements are applicable in common optical or hybrid electro-optical networks where not all of the optical signals in the network are compatible with all network elements participating in the network. This compatibility constraint model is applicable to common optical or hybrid electro optical systems such as OEO switches, regenerators, and wavelength converters since such systems can be limited to processing only certain types of WSON signals. Related to this document is [RFC7580] which provides GMPLS OSPF routing enhancements to support the generic routing and label assignment process that can be applicable to a wider range of technologies beyond WSON. 2. The Optical Node Property TLV [RFC3630] defines OSPF Traffic Engineering (TE) Link State Advertisement (LSA) using an opaque LSA. This document adds a new top level TLV for use in the OSPF TE LSA: the Optical Node Property TLV. The Optical Node Property TLV describes a single node. It is comprised of a set of optional sub-TLVs. There are no ordering requirements for the sub-TLVs. Lee and Bernstein Expires November 2014 [Page 3] Internet-Draft OSPF Enhancement for WSON August 2015 When using the extensions defined in this document, at least one Optical Node Property TLV MUST be advertised in each LSA. To allow for fine granularity changes in topology, more than one Optical Node Property TLV MAY be advertised in a single LSA. Implementations MUST support receiving multiple Optical Node Property TLVs in an LSA. The Optical Node Property TLV contains all WSON-specific node properties and signal compatibility constraints. The detailed encodings of these properties are defined in [RFC7581]. The following sub-TLVs of the Optical Node Property TLV are defined: Value Length Sub-TLV Type TBA1 variable Resource Block Information TBA2 variable Resource Accessibility TBA3 variable Resource Wavelength Constraints TBA4 variable Resource Block Pool State TBA5 variable Resource Block Shared Access Wavelength Availability The detailed encodings of these sub-TLVs are found in [RFC7581] as indicated in the table below. Sub-TLV Type Section [RFC7581] Resource Block Information 4.1 Resource Accessibility 3.1 Resource Wavelength Constraints 3.2 Resource Block Pool State 3.3 Resource Block Shared Access Wavelength Availability 3.4 All sub-TLVs defined here may occur at most once in any given Optical Node TLV under one TE LSA. If more than one copy of the sub- TLV is received in the same LSA, the redundant sub-TLV SHOULD be ignored. In case where the same sub-TLV is advertised in different TE LSA (which would take place only by a packaging error), then the sub-TLV with the largest LSA ID (Sec 2.2 of RFC 3630) SHOULD be picked. These restriction need not apply to future sub-TLVs. Unrecognized sub-TLVs are ignored. Among the sub-TLVs defined above, the Resource Block Pool State sub- TLV and Resource Block Shared Access Wavelength Availability are dynamic in nature while the rest are static. As such, they can be Lee and Bernstein Expires November 2014 [Page 4] Internet-Draft OSPF Enhancement for WSON August 2015 separated out from the rest and be advertised with multiple TE LSAs per OSPF router, as described in [RFC3630] and [RFC5250]. 2.1. Resource Block Information As defined in [RFC7446], this sub-TLV is used to represent resource signal constraints and processing capabilities of a node. 2.2. Resource Accessibility This sub-TLV describes the structure of the resource pool in relation to the switching device. In particular, it indicates the ability of an ingress port to reach a resource block and of a resource block to reach a particular egress port. 2.3. Resource Wavelength Constraints Resources, such as wavelength converters, etc., may have limited input or output wavelength ranges. Additionally, due to the structure of the optical system, not all wavelengths can necessarily reach or leave all the resources. The Resource Wavelength Constraints sub-TLV describes these properties. 2.4. Resource Block Pool State This sub-TLV describes the usage state of a resource that can be encoded as either a list of integer values or a bit map indicating whether a single resource is available or in use. This information can be relatively dynamic, i.e., can change when a connection is established or torn down. 2.5. Resource Block Shared Access Wavelength Availability Resource blocks may be accessed via a shared fiber. If this is the case, then wavelength availability on these shared fibers is needed to understand resource availability. 3. Interface Switching Capability Descriptor (ISCD) Format Extensions The ISCD describes switching capability of an interface [RFC4202]. This document defines a new Switching Capability value for WSON as follows: Value Type Lee and Bernstein Expires November 2014 [Page 5] Internet-Draft OSPF Enhancement for WSON August 2015 ----- ---- 151 (TBA by IANA) WSON-LSC capable (WSON-LSC) Switching Capability and Encoding values MUST be used as follows: Switching Capability = WSON-LSC Encoding Type = Lambda [as defined in RFC3471] When Switching Capability and Encoding fields are set to values as stated above, the Interface Switching Capability Descriptor MUST be interpreted as in [RFC4203] with the optional inclusion of one or more Switching Capability Specific Information sub-TLVs. 3.1. Switching Capability Specific Information (SCSI) The technology specific part of the WSON ISCD may include a variable number of sub-TLVs called Bandwidth sub-TLVs. Two types of Bandwidth sub-TLV are defined: - Type 1 - Available Labels - Type 2 - Shared Backup Labels A SCSI may contain multiple Available Label sub-TLVs and multiple Shared Backup Label sub-TLVs. The following figure shows the format for a SCSI that contains these sub-TLVs. The order of the sub-TLVs in the SCSI is arbitrary. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Available) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Available Label Sub-TLV | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ... ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 2 (Shared backup) | Length | Lee and Bernstein Expires November 2014 [Page 6] Internet-Draft OSPF Enhancement for WSON August 2015 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Shared Backup Label Sub-TLV | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: SCSI format Where the Available Label Sub-TLV and Shared Backup Label sub-TLV are defined in [RFC7579]. In case where duplicated sub-TLVs are advertised, the router/node will ignore the duplicated labels which are identified by the Label format defined in [RFC6205]. The label format defined in [RFC6205] MUST be used when advertising interfaces with a WSON-LSC type Switching Capability. 4. WSON Specific Scalability and Timeliness This document has defined five sub-TLVs specific to WSON. The examples given in [RFC7581] show that very large systems, in terms of channel count, ports, or resources, can be very efficiently encoded. There has been concern expressed that some possible systems may produce LSAs that exceed the IP Maximum Transmission Unit (MTU). In a typical node configuration, the optical node property TLV will not exceed the IP MTU. A typical node configuration refers to a system with several hundreds of channels with an OEO element in the node. This would give optical node property TLV less than 350 bytes. In addition, [RFC7581] provides mechanisms to compactly encode required information elements. In a rare case where the TLV exceed the IP MTU, IP fragmentation/reassembly can be used, which is an acceptable method. For IPv6, a node may use the IPv6 Fragment header to fragment the packet at the source and have it reassembled at the destination(s). If the size of this LSA is greater than the MTU, then these sub-TLVs can be packed into separate LSAs. From the point of view of path computation, the presence of the Resource Block Information sub-TLV indicates that resources exist in the system and may have signal compatibility or other constraints. The other four sub-TLVs indicate constraints on access to, and availability of those resources. Lee and Bernstein Expires November 2014 [Page 7] Internet-Draft OSPF Enhancement for WSON August 2015 Hence the "synchronization" procedure from a path computation point of view is quite simple. Until a Resource Block Information sub-TLV is received for a system, path computation cannot make use of the other four sub-TLVs since it does not know the nature of the resources, e.g., are the resources wavelength converters, regenerators, or something else. Once this sub-TLV is received, path computation can proceed with whatever sub-TLVs it may have received (there use is dependent upon the system type). If path computation proceeds with out of date or missing information from these sub-TLVs, then there is the possibility of either (a) path computation computing a path that does not exist in the network, (b) path computation failing to find a path through the network that actually exists. Both situations are currently encountered with GMPLS, i.e., out of date information on constraints or resource availability. In case where the new sub-TLVs or their attendant encodings are malformed, the proper action SHOULD log the problem and MUST stop sending the LSA in which to contain malformed TLVs or sub-TLVs. Errors of this nature SHOULD be logged for the local operator. Implementations MUST provide a rate limit on such logs, and that rate limit SHOULD be configurable. Note that the connection establishment mechanism (signaling or management) is ultimately responsible for the establishment of the connection, and this implies that such mechanisms must insure signal compatibility. 5. Security Considerations This document does not introduce any further security issues other than those discussed in [RFC3630], [RFC4203]. As with [RFC4203], it specifies the contents of Opaque LSAs in OSPFv2. As Opaque LSAs are not used for Shortest Path First (SPF) computation or normal routing, the extensions specified here have no direct effect on IP routing. Tampering with GMPLS TE LSAs may have an effect on the underlying Transport. [RFC3630] notes that the security mechanisms described in [RFC2328] apply to Opaque LSAs carried in OSPFv2. Lee and Bernstein Expires November 2014 [Page 8] Internet-Draft OSPF Enhancement for WSON August 2015 For general security aspects relevant to Generalized Multiprotocol Label Switching (GMPLS)-controlled networks, please refer to [RFC5920]. 6. IANA Considerations 6.1. Optical Node Property TLV This document introduces a new Top Level Node TLV (Optical Node Property TLV) under the OSPF TE LSA defined in [RFC3630]. IANA is asked to register a new TLV for "Optical Node Property". The new TLV will be registered in the "Top Level Types in TE LSAs" registry in "OSPF Traffic Engineering TLVs", located at http://www.iana.org/assignments/ospf-traffic-eng-tlvs, as follows: Value TLV Type Reference 6 (TBA6) Optical Node Property [This.ID] 6.1.1. Optical Node Property Sub-TLV Additionally, a new IANA registry will be created for sub-TLVs of the Optical Node Property TLV to create a new section named "Types of sub-TLVs of Optical Node Property TLV (Value TBA)" in the "OSPF Traffic Engineering TLVs" registry located at http://www.iana.org/assignments/ospf-traffic-eng-tlvs/ospf-traffic- eng-tlvs.xml, and allocate new sub-TLV Types and their Values for these sub-TLVs defined under the Optical Node Property TLV as follows: Value Length Sub-TLV Type Reference Lee and Bernstein Expires November 2014 [Page 9] Internet-Draft OSPF Enhancement for WSON August 2015 0 Reserved 1 (TBA1) variable Resource Block Information [This.ID] 2 (TBA2) variable Resource Accessibility [This.ID] 3 (TBA3) variable Resource Wavelength Constraints [This.ID] 4 (TBA4) variable Resource Block Pool State [This.ID] 5 (TBA5) variable Resource Block Shared Access Wavelength Availability [This.ID] 6-65535 Unassigned Types are to be assigned via Standards Action as defined in [RFC5226]. 6.2. WSON-LSC Switching Type TLV IANA is asked to register a new switching type for "WSON-LSC capable" in the Switching Types registry in "GMPLS Signaling Parameters", located at http://www.iana.org/assignments/gmpls-sig- parameters/, as follows: Switching capability Description Reference ---------------------- -------------------------- ---------- 151 (TBA7) WSON-LSC capable (WSON-LSC) [This.ID] 6.2.1. WSON-LSC SCSI Sub-TLVs Additionally, a new IANA registry will be created for sub-TLVs of the WSON-LSC SCSI sub-TLV to create a new section/sub-registry named "Types for sub-TLVs of WSON-LSC SCSI (Switch Capability-Specific Information)" section under the "OSPF Traffic Engineering TLVs" registry, with the following sub-TLV types: Value Sub-TLV Reference 0 Reserved 1 (TBA8) Available Labels [This.ID] 2 (TBA9) Shared Backup Labels [This.ID] 3-65535 Unassigned Types are to be assigned via Standards Action as defined in [RFC5226]. Lee and Bernstein Expires November 2014 [Page 10] Internet-Draft OSPF Enhancement for WSON August 2015 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3630] Katz, D., Kompella, K., and Yeung, D., "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, September 2003. [RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4203, October 2005. [RFC6205] T. Otani, Ed. and D. Li, Ed., "Generalized Labels for Lambda-Switch-Capable (LSC) Label Switching Routers", RFC 6205, March 2011. [RFC7581] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and Wavelength Assignment Information Encoding for Wavelength Switched Optical Networks", RFC 7581, June 2015. [RFC7579] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "General Network Element Constraint Encoding for GMPLS Controlled Networks", RFC 7579, June 2015. [RFC7580] F. Zhang, Y. Lee, J. Han, G, Bernstein and Y. Xu, "OSPF-TE Extensions for General Network Element Constraints", RFC 7580, June 2015. 7.2. Informative References [RFC7446] Y. Lee, G. Bernstein, D. Li, W. Imajuku, "Routing and Wavelength Assignment Information Model for Wavelength Switched Optical Networks", RFC 7446, February 2015. [RFC4202] K. Kompella, Ed., and Y. Rekhter, Ed., "Routing Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4202, October 2005. [RFC6163] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks", RFC 6163, April 2011. Lee and Bernstein Expires November 2014 [Page 11] Internet-Draft OSPF Enhancement for WSON August 2015 [RFC5250] Berger, L., et al., "The OSPF Opauqe LSA option", RFC 5250, July 2008. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC5920] Luyuan Fang(Ed.), "Security Framework for MPLS and GMPLS N Networks", RFC5920, July 2010. 8. Authors' Addresses Young Lee (ed.) Huawei Technologies 5340 Legacy Drive, Building 3 Plano, TX 75024 USA Phone: (469)277-5838 Email: leeyoung@huawei.com Greg M. Bernstein (ed.) Grotto Networking Fremont California, USA Phone: (510) 573-2237 Email: gregb@grotto-networking.com Lee and Bernstein Expires November 2014 [Page 12]