CCAMP Working Group Mohit Misra Internet-Draft Rajan Rao Intended status: Proposed Standard Ashok Kunjidhapatham Expires: April 27, 2011 Khuzema Pithewan Infinera Corp November 08, 2010 Signaling Extensions for Generalized MPLS (GMPLS) Control of G.709 Optical Transport Networks draft-khuzema-ccamp-gmpls-signaling-g709-00.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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2010 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 Legal Provisions and are provided without warranty as described in the Simplified BSD License. Khuzema, et al. Expires April 27, 2011 [Page 1] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 Abstract As OTN network capabilities continue to evolve, there is an increased need to support GMPLS control for the same. [RFC4328] introduced GMPLS signaling extensions for supporting early version of G.709 [G.709-v1].The basic routing considerations from signaling perspective is also specified in [RFC4328]. The recent revision of ITU-T Recommendation G.709 [G.709-v3] and [GSUP.43] have introduced new ODU containers (both fixed and flexible) and additional ODU multiplexing capabilities, enabling support for optimal service aggregation. This document extends [RFC4328] to provide GMPLS signaling support for the new OTN capabilities defined in [G.709-v3] and [GSUP.43]. The signaling extensions described in this document caters to ODU layer switching only. Optical Channel Layer switching considerations in [RFC4328] are not modified in this document. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . . 4 3. Overview of GMPLS Signaling Extensions required for the Evolving OTN . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Extensions to G.709 Traffic Parameters . . . . . . . . . . . . . 5 4.1. Usage of Bit_Rate and Tolerance for ODUflex Service . . . . 6 5. New Generalized Label Format . . . . . . . . . . . . . . . . . . 7 5.1. Label format for NVC or Multiplier > 1 . . . . . . . . . . 9 6. Label Distribution Rules . . . . . . . . . . . . . . . . . . . . 9 7. Interoperability Considerations . . . . . . . . . . . . . . . 10 7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 10.1. Normative References . . . . . . . . . . . . . . . . . 11 10.2. Informative References . . . . . . . . . . . . . . . . 11 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 Author's Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 Khuzema, et al. Expires April 27, 2011 [Page 2] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 1. Introduction Generalized Multi-Protocol Label Switching (GMPLS) [RFC3945] extends MPLS from supporting Packet Switching Capable (PSC) interfaces and switching to include support of four new classes of interfaces and switching: Layer-2 Switching (L2SC), Time-Division Multiplex (TDM), Lambda Switch (LSC), and Fiber-Switch (FSC) Capable. A functional description of the extensions to MPLS signaling that are needed to support these new classes of interfaces and switching is provided in [RFC3471]. ITU-T Recommendations G.709 and G.872 provide specifications for OTN interface and network architecture respectively. As OTN network capabilities continue to evolve; there is an increased need to support GMPLS control for the same. GMPLS signaling extensions to support [G.709-v1] OTN interfaces are specified in [RFC4328]. Further extensions are required to support the new capabilities introduced since [G.709-v1]. Following are the features added in OTN since the first version [G.709-v1]. (a) OTU Containers: Pre-existing Containers: OTU1, OTU2 and OTU3 New Containers introduced in [G.709-v3]: OTU2e and OTU4 New Containers introduced in [GSUP.43]: OTU1e, OTU3e1 and OTU3e2 (b) Fixed ODU Containers: Pre-existing Containers: ODU1, ODU2 and ODU3 New Containers introduced in [G.709-v3]: ODU0, ODU2e and ODU4 New Containers introduced in [GSUP.43]: ODU1e, ODU3e1 and ODU3e2 (c) Flexible ODU Containers: ODUflex for CBR and GFP-F mapped services. ODUflex uses 'n' number of OPU Tributary Slots where 'n' is different from the number of OPU Tributary Slots used by the Fixed ODU Containers. (d) Tributary Slot Granularity: OPU2 and OPU3 support two Tributary Slot Granularities: (i) 1.25Gbps and (ii) 2.5Gbps. (e) Multi-stage ODU Multiplexing: Multi-stage multiplexing of LO-ODUs into HO-ODU is supported. Also, multiplexing could be heterogeneous (meaning LO-ODUs of different rates can be multiplexed into a HO-ODU). OTN networks support switching at two layers: (i) ODU Layer - TDM Switching and (ii) OCH Layer - Lambda (LSC) Switching. The nodes on Khuzema, et al. Expires April 27, 2011 [Page 3] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 the network may support one or both the switching types. When multiple switching types are supported MLN based routing [RFC5339] is assumed. This document extends [RFC4328] to provide GMPLS signaling support for the new OTN capabilities defined in [G.709-v3] and [GSUP.43]. This complies with the requirements outlined in the framework document [G.709-FRAME]. The signaling extensions described in this document caters to ODU layer switching only. Optical Channel Layer switching considerations in [RFC4328] are not modified in this document. Following are the extensions described in this document: (i) G.709 Traffic Parameters defined in [RFC4328] is extended to include Bit Rate (in bytes/second) and Tolerance (in ppm) fields for supporting ODUflex service. (ii) New Generalized Label Format is introduced to provide compact encoding of Tributary Slot information and support multi-stage multiplexing. 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 is to be interpreted as described in RFC-2119 [RFC2119]. In addition, the reader is assumed to be familiar with the terminology used in ITU-T [G.709-v3], [G.872] and [GSUP.43], as well as [RFC4201] and [RFC4203]. 3. Overview of GMPLS Signaling Extensions required for the Evolving OTN The GMPLS signaling extensions introduced in [RFC4328] cover OTN switching requirement pertaining to [G.709-v1]. The signaling objects defined in [RFC4328] need to be further extended to cover the new capabilities added to OTN since the first version of G.709 [G.709-v1]. A brief overview of the extensions required are captured below: (a) Support for the new ODU containers The new ODU containers added since [G.709-v1] are listed in the section-1. SignalType attribute defined in [RFC4328] need to be extended to cover the new signal types. This is captured in [OSPF- EXTN-FOR-OTN]. Khuzema, et al. Expires April 27, 2011 [Page 4] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 (b) Support for ODUflex Unlike the other ODUj signal types, ODUflex requires an user specified bit-rate (together with a Tolerance value) to be mapped to 'n' TSs of an higher-order container. Even within the same Tributary Slot Granularity, the Tributary Slot size varies among the ODU container of different rate. This results in ODUflex service of certain bit-rate and tolerance requiring different number of TSs on different higher order ODU containers. The present way of specifying bandwidth requirement (via NMC field in G.709 Traffic Parameters) will not work for ODUflex. G.709 Traffic Parameters object need to be extended to include Bit-Rate (in bytes/sec) and Tolerance (in ppm) fields as well. (c) Support for multi-stage multiplexing The G.709 Traffic Parameter and Generalized Label Format defined in [RFC4328] supports single stage multiplexing only. A new Generalized Label Format need to be introduced to support specification of multi- stage label. ODUk-------------------ODUj-------------------ODUh Label for Stage-1 Label for Stage-2 Figure-1: Multi-stage Label (d) Support for different OPU Tributary Slot Granularities The G.709 Traffic Parameters and Generalized Label Format defined in [RFC4328] supports 2.5Gbps Tributary Slot Granularity only. With [G.709-v3], two types of tributary slots are supported - viz., 1.25Gbps and 2.5Gbps. The Generalized Label Format need to be equipped with Tributary Slot Type indicator to facilitate interpretation of the encoded TS information. (e) Exchange of Tributary Port Number A Tributary Port Number (TPN) in MSI field of OPU-OH is used to correlate the TSs used for mapping a LO-ODU on a HO-ODU. This needs to be exchanged along with the Label such that each neighbor on a span knows the TPN value to expect for a given ODUj mapping. This applies to each stage associated with a multi-stage label. The Generalized Label Format needs to be extended to include TPN value for each stage of multiplexing. 4. Extensions to G.709 Traffic Parameters G.709 Traffic Parameters defined in [RFC4328] is extended to include Khuzema, et al. Expires April 27, 2011 [Page 5] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 additional fields in support of ODUflex service as explained in the previous section. The modified object format is captured below: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signal Type | Reserved | NMC/Tolerance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | NVC | Multiplier (MT) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Bit_Rate | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Signal Type As explained in the previous section, Signal Type attribute needs to be extended to cover the new ODU containers added. This is captured in [OSPF-EXTN-FOR-OTN]. NMC/Tolerance This field is redefined from the original definition in [RFC4328]. NMC field defined in [RFC4328] can not be fixed value for an end-to- end circuit involving dissimilar OTN link types. For example, ODU2e requires 9 TS on ODU3 and 8 TS on ODU4. Usage of NMC field is deprecated and should be used only with [RFC4328] generalized label format for backwards compatibility reasons. For the new generalized label format as defined in this document this field is interpreted as Tolerance. The unit of tolerance is ppm and is encoded as unsigned integer. For signal types other than ODUflex, Tolerance field should be coded as 0. Bit_Rate Bit_Rate is used when signal Type is ODUFlex. For all the other signal types, this field should be coded as zero. 4.1. Usage of Bit_Rate and Tolerance for ODUflex Service Bit_Rate and Tolerance are used together to compute number of Tributary slots required for ODUFlex(CBR) traffic on a given higher order ODU container. The computation of Number of Tributary Slot (n) is as follows. Ceiling of Bit_Rate * (1 + Tolerance) n = -------------------------------------------------- ODTUk.ts nominal bit rate * (1 - HO OPUk bit rate tolerance) Khuzema, et al. Expires April 27, 2011 [Page 6] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 5. New Generalized Label Format As explained in section 3, the Generalized Label format defined in [RFC4328] can not accommodate the new features added in [G.709v3]. Further the label format as defined in [RFC4328] is not scalable for large number of Tributary Slots (at 1.25G granularity) associated with bigger containers such as ODU3 and ODU4. The Generalized Label for G.709 may contain one more multi-stage label. A multi-stage label includes TS and TPN information for all stages of a multi-stage multiplexing hierarchy. The format of a multi-stage label is explained below. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Num MUX Stages| OD(T)Uk (ST) | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage-1 Time Slot Info | | (Variable Length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage-n Time Slot Info | | (Variable Length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Num MUX Stages This field indicates the number of multiplexing stages specified by the label. OD(T)Uk This field encodes the signal type of HO OD(T)Uk container. TS Information for a single stage is encoded as follows. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ODUj (ST) | T | Length | Tributary Port Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Variable Length Bit Map (4-byte boundary aligned) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Khuzema, et al. Expires April 27, 2011 [Page 7] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 ODUj This field indicates the signal type of a LO-ODU being multiplexed into its immediate HO-ODU. T This is a 2 bit field, which defines the granularity of tributary slots for this multiplexing stage. It can take following values T field TS Granularity type ------- ------------------- 0 1.25Gbps 1 2.5Gbps 2-3 Reserved (for future use) Length This field indicates the number of valid Bits in the of Bit Map excluding the filler bits. Tributary Port Number(TPN) This field is encoded with TPN value assigned for a ODTUjk or ODTUk.ts on a OPUk. TPN assignment could be fixed or flexible. For fixed TPN assignment scheme, TPN value need not be specified. In this case, TPN value should be coded as 0xFFFFFFFF. For flexible TPN assignment scheme, TPN value should contain the assigned logical value. Not all the bits of TPN are used. Only a subset of bits are used depending on the OPUk type. Bits Used ODU Container --------- ------------- 0-5 ODU1 to ODU3 0-6 ODU4 7-15 Reserved The reserved bits should be coded as zeros for flexible assignment scheme. Bit Map This is a multi-byte bit map field. The length of this field varies depending on the number of TSs associated with the immediate HO-ODU Khuzema, et al. Expires April 27, 2011 [Page 8] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 pertaining to the stage. Each bit represents one TS. Bit values are interpreted as follows Bit Value Meaning --------- ------- 0 Not Used 1 Used This field must be 4 byte aligned using filler bytes. 5.1. Label format for NVC or Multiplier > 1 For NVC or Multiplier field value > 1, the label format defined in section 5 needs to be repeated NVC/multiplier times. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label Instance #1 | | (Variable Length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Label Instance #n | | (n = NVC/Multiplier) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 6. Label Distribution Rules This document does not change the existing label distribution procedures defined in [RFC4328] except that the new ODU label should be processed as follows. A. Sending Side When Generalized Label Request is received on given node for setting up a ODU LSP from its upstream neighbor, it reserves the resources required on an OTN interface and send the label back to upstream neighbor. Note that Label can also be explicitly specified by source node. The encoding of Generalized Label is as follows: For ODUj to ODUk multiplexing, the length field indicates the number of TS supported on ODUk. TS reserved for ODUj are marked as 1. For ODUk to OTUk mapping, the length field is coded as 0 and BitMap field is not included. Khuzema, et al. Expires April 27, 2011 [Page 9] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 B. Receiving Side For ODUj to ODUk multiplexing, the node extracts the Bit Map field using the Length field. The position of Bit in the Bitmap interpreted as the Trib Slot Number. The value stored in the bit indicates if it is reserved for the ODUj. For ODUk to OTUk mapping, the length is 0. Hence, bitmap field is not expected. 7. Interoperability Considerations The neighbor nodes on a TE-Link span should exchange the signaling stack versions (via some link discovery mechanism) in order to determine the Generalized Label Format to use. In the following example, Switch B and C are running the newer version of signaling stack (that support the new G.709 Traffic Parameters and Generalized Label Format) while Switch A is running the older version. +-------+ +-------+ +-------+ | OTN | | OTN | | OTN | |Switch |<- OTUk Link ->|Switch |<- OTUk Link ->|Switch | | A | | B | | C | +-------+ +-------+ +-------+ |<-- Legacy -->| |<-- New TE-Link -->| Figure-1: OTUk TE-Link Link A-B: G.709-v1 version (2001) based OTUk link TSG: 2.5G; Label format: as per RFC 4328 Link B-C: G.709-v3 version based OTUk link (12/09) TSG: 1.25G; Label format: new label format proposed in this draft. For an ODU2 connection going from A-C, On link A-B : NMC is set to 4 & [RFC4328] label format is used. On link B-C : NMC is not used & new label format is used. 7. Examples Khuzema, et al. Expires April 27, 2011 [Page 10] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 8. Security Considerations There are no additional security implications to Signaling protocol due to the extensions captured in this document. 9. IANA Considerations TBD 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels". [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630 [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC4201] Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling in MPLS Traffic Engineering (TE)" [RFC4203] Kompella, K. and Y. Rekhter, "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)" [RFC4204] Lang, J., Ed., "Link Management Protocol (LMP)", RFC 4204, October 2005. [RFC4328] Papadimitriou, D., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Extensions for G.709 Optical Transport Networks Control", RFC 4328, January 2006. [RFC5339] Le Roux, JL. and D. Papadimitriou, "Evaluation of Existing GMPLS Protocols against Multi-Layer and Multi-Region Networks (MLN/MRN)", RFC 5339, September 2008. [G.709-v3] ITU-T, "Interfaces for the Optical Transport Network (OTN)", G.709 Recommendation, December 2009. 10.2. Informative References [RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching (GMPLS) Architecture", RFC 3945, October 2004. Khuzema, et al. Expires April 27, 2011 [Page 11] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 [G.709-v1] ITU-T, "Interface for the Optical Transport Network (OTN)," G.709 Recommendation (and Amendment 1), February 2001 (October 2001). [G.872] ITU-T, "Architecture of optical transport networks", November 2001 (11 2001). [G.709-FRAME] F. Zhang, D. Li, H. Li, S. Belotti, "Framework for GMPLS and PCE Control of G.709 Optical Transport Networks", draft-zhang-ccamp-gmpls-g709-framework-02, work in progress. [WSON-FRAME] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks (WSON)", draft-ietf-ccamp-rwa-wson-framework, work in progress. 11. Acknowledgements Authors would like to thank Lou Berger and Biao Lu for review comments and suggestions. Author's Addresses Mohit Misra Infinera Corporation 169, Java Drive Sunnyvale, CA-94089 USA Email: mmisra@infinera.com Rajan Rao Infinera Corporation 169, Java Drive Sunnyvale, CA-94089 USA Email: rrao@infinera.com Ashok Kunjidhapatham Infinera Corporation 169, Java Drive Sunnyvale, CA-94089 USA Email: akunjidhapatham@infinera.com Khuzema, et al. Expires April 27, 2011 [Page 12] Internet-Draft draft-khuzema-ccamp-gmpls-sig-g709-00.txtOctober 24, 2010 Khuzema Pithewan Infinera Corporation 169, Java Drive Sunnyvale, CA-94089 USA Email: kpithewan@infinera.com Khuzema, et al. Expires April 27, 2011 [Page 13]