Network Working Group Abinder Dhillon Iftekhar Hussain Rajan Rao Internet Draft Infinera Intended status: Standard Track October 31, 2011 Expires: April 2012 OSPFTE extension to support GMPLS for Flex Grid draft-dhillon-ccamp-super-channel-ospfte-ext-01.txt Abstract This document specifies the extension to TELINK LSA of OSPF routing protocol [RFC4203] [3] in support of GMPLS [1] for flex-grid networks [2]. 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." 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Table of Contents 1. Introduction...................................................2 2. Terminology....................................................3 3. Interface Switching Capability Descriptor......................3 3.1. Switch Capability Specific Information ....................4 3.2. BW advertisement procedure................................6 3.2.1. Example - BW advertisement W/O any service present...6 3.2.2. Example - How to use advertized Bandwidth............7 4. Security Considerations........................................8 5. IANA Considerations............................................8 6. References.....................................................8 6.1. Normative References......................................8 6.2. Informative References....................................8 7. Acknowledgments................................................9 1. Introduction To enable scaling of existing transport systems to ultra high data rates of 1 Tbps and beyond, next generation systems providing super- channel switching capability are currently being developed. To allow efficient allocation of optical spectral bandwidth for such high bit rate systems, International Telecommunication Union Telecommunication Standardization Sector (ITU-T) is extending the G.694.1 grid standard (termed ''Fixed-Grid'') to include flexible grid (termed ''Flex-Grid'') support. This document defines OSPF-TE extensions in support of flex-grid networks. Figure-1 shows a network consisting of Network Elements(NEs) with super channel switching capability. User can create super channel connections using GMPLS through these NEs. Dhillon Expires April 2012 [Page 2] Internet-Draft Super-Channel-Switching-Cap October 2011 To support the routing function in GMPLS for flex-grid network, NE models each flex-grid link (C-band or C-band-extended) with new switching capability and provides optical bandwidth in terms of 12.5 GHz spectral slices. This information is flooded in OSPFTE. During path calculation time, NE selects only that path where all the telinks support super channel switching and have required set of 12.5 GHz slices available. NE then signals along that path to establish super channel connection. Once the connection is established then spectral slice availability is updated in each telink and flooded back in OSFPTE. +-------+ +-------+ +-------+ | SC | | SC | | SC | |Switch |.---Link ---> |Switch |<- Link----- ->|Switch | | A | | B | | C | +-------+ +-------+ +-------+ |<-- TE-Link -->| |<-- TE-Link -->| Figure 1: TE-Links 2. Terminology 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]. 3. Interface Switching Capability Descriptor The Interface Switching Capability Descriptor describes switching capability of an interface [RFC 4203]. This document defines a new Switching Capability value for Flex Grid [G.694.1] as follows: Value Type ----- ---- 102 (TBA by IANA) Super-Channel-Switch-Capable(SCSC) Switching Capability and Encoding values MUST be used as follows: Switching Capability = SCSC Encoding Type = Lambda [as defined in RFC3471] Dhillon Expires April 2012 [Page 3] Internet-Draft Super-Channel-Switching-Cap October 2011 The Interface Switching Capability Descriptor is a sub-TLV (of type 15) of the Link TLV. The length is the length of value field in Octets. The format of the value field is as shown 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Switching Cap | Encoding | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Max LSP Bandwidth at priority 7 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Switching Capability-specific information | | (variable) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Maximum LSP BW is really not used for super channel connection. All the required information is in terms of spectral slices which are distributed within the ISCD specific portion of the ISCD for flex grid telink. 3.1. Switch Capability Specific Information The technology specific part of the ISCD can include a variable number of sub-TLVs. We propose to include following sub-TLVs under SCSI field: 0 1 2 3 Dhillon Expires April 2012 [Page 4] Internet-Draft Super-Channel-Switching-Cap October 2011 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 | Length | +---------------------------------------------------------------+ |Grid | S.S | Res | Priority | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | BW sub-TLV(s) one per priority | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: SCSI Format for ISCD=SCSD 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 | Length | +---------------------------------------------------------------+ | N-Start | Slice Count | +---------------------------------------------------------------+ | Min S.W per LSP | Max S.W per LSP | +---------------------------------------------------------------+ | | | Bit-Map showing Available 12.5GHz Slots | | (upto 48 bytes per priority) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: BW sub-tlv Various attributes in ISCD specific information TLV and Bandwidth sub-tlv are as following: . Grid = FlexGrid; . Slice Spacing (S.S) = 12.5GHz; . Priority bit map to show priorities supported o Up to 8 priorities can be supported . N-Start - - integer, specifies start of the grid; Dhillon Expires April 2012 [Page 5] Internet-Draft Super-Channel-Switching-Cap October 2011 o Use center freq formula to determine start of spectrum . Slice Count o Total number of slices advertised for the link (available + consumed) . Min Slot Width per LSP o This is an integer value. nxS.S; n > 0 ; . Max Slot Width per LSP o This is an integer value; nxS.S; n < some integer value up to Slice Count . Available BW encoded as bit-map o Each bit represents availability of one slice of width identified by S.S field o Zero - - Available ; One - occupied 3.2. BW advertisement procedure This section describes bandwidth advertisement of telink when ISCD is of type SCSD. Key points are: o An Optical node capable of Super Channel Switching advertises slices of certain width available based on the frequency spectrum supported by the node(e.g. C band, extended C-band). For example extended C-band will advertize 384 slices. o The BW advertisement involves a bit-map where each bit corresponds to a single slice of width as identified by S.S field. o The slice position/numbering in the bit-map is identified based on N-start field. The N-start field is derived based on ITU center frequency formula. o The advertising node MUST also set Slice-Count field. o Minimum & Maximum slot width fields are included to allow for any restrictions on the link for carrying super channel LSPs. o The BW advertisement is priority based and up to 8 priority levels are allowed. o The node capable of supporting one or more priorities MUST set the priority field and include BW-sub TLV for each of the priority supported. 3.2.1. Example - BW advertisement W/O any service present Figure 5 shows an example of BW sub-tlv for a telink which has no service established over it yet. Attributes of BW sub-tlv in the telink are: o N-start=-142 for extended C-band Dhillon Expires April 2012 [Page 6] Internet-Draft Super-Channel-Switching-Cap October 2011 o Total number of slices available on the link = 384 (based on Slice spacing = 12.5GHz) o Min SW field shows min consumption of 4 Slices per LSP ( =50GHz) o Max SW field shows up to 400GHz BW allowed per LSP (32x12.5GHz) o 48 bytes showing that all 384 slices are available. 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 | Length | +---------------------------------------------------------------+ | N-Start=-142 | Slice Count=384 | +---------------------------------------------------------------+ | Min S.W per LSP=4 | Max S.W per LSP=32 | +---------------------------------------------------------------+ | | | Bit-Map with a bit for each 12.5GHz Slot. | | (384 bits - - each bit-set to value zero to show it | | is unused | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: TELINK BW sub-tlv w/o any service present 3.2.2. Example - How to use advertized Bandwidth Assume user wants to setup Super Channel LSP over a single FlexGrid link with BW requirement = 250GHz and transponder fully tunable. o The path computing node performs the following: o Determine the number of slices required for the LSP (250/S.S = 20) Dhillon Expires April 2012 [Page 7] Internet-Draft Super-Channel-Switching-Cap October 2011 o Look for contiguous spectrum availability on each link from BW adv (both dir) o Look for 20 contiguous bits in the BW advertisement TLV o If available select the link for LSP creation. . Signal for LSP creation. Once LSP is created , update BW available via new advertisement using the same Bandwidth sub-TLV. 4. Security Considerations 5. IANA Considerations IANA needs to assign a new Grid field value to represent ITU-T Flex- Grid. 6. References 6.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 6.2. Informative References [1] Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003 [2] Iftekhar H, Abinder, Zhong, Marco, Bert, Steve, Andrew, ''Generalized Label for Super-Channel Assignment on Flexible Grid'', draft-hussain-ccamp-super-channel-label-02.txt, October 2011. [3] K. Kompella, Y., " OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4203, Oct 2005 [4] Lee, Y., Ed., "Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)", RFC 6163, April 2011 Dhillon Expires April 2012 [Page 8] Internet-Draft Super-Channel-Switching-Cap October 2011 [5] M. Jinno et. al., ''Spectrum-Efficient and Scalable Elastic Optical Path Network: Architecture, Benefits and Enabling Technologies'', IEEE Comm. Mag., Nov. 2009, pp. 66-73. [6] S. Chandrasekhar and X. Liu, ''Terabit Super-Channels for High Spectral Efficiency Transmission '',in Proc. ECOC 2010, paper Tu.3.C.5, Torino (Italy), September 2010. [7] ITU-T Recommendation G.694.1, "Spectral grids for WDM applications: DWDM frequency grid", June 2002 [8] A. Farrel, D King, ''Generalized Labels for the Flexi-Grid inLambda-Switch-Capable (LSC) Label Switching Routers'', Work in progress:draft-farrkingel-ccamp-flexigrid-lambda-label- 00.txt - - October 2011. [9] G. Bernstein, Y. Lee, D. Li, W. Imajuku, " General Network Element Constraint Encoding for GMPLS Controlled Networks", work in progress: draft-ietf-ccamp-general-constraint- encode-05, May 2011 7. Acknowledgments Dhillon Expires April 2012 [Page 9] Internet-Draft Super-Channel-Switching-Cap October 2011 Authors' Addresses Abinder Dhillon Infinera 140 Caspian Ct., Sunnyvale, CA 94089 Email: adhillon@infinera.com Iftekhar Hussain Infinera 140 Caspian Ct., Sunnyvale, CA 94089 Email: ihussain@infinera.com Rajan Rao Infinera 140 Caspian Ct., Sunnyvale, CA 94089 Email: rrao@infinera.com Dhillon Expires April 2012 [Page 10] Internet-Draft Super-Channel-Switching-Cap October 2011 Contributor's Addresses Marco Sosa Infinera 140 Caspian Ct., Sunnyvale, CA 94089 Email: msosa@infinera.com Biao Lu Infinera 140 Caspian Ct., Sunnyvale, CA 94089 Email: blu@infinera.com Subhendu Chattopadhyay Infinera 140 Caspian Ct., Sunnyvale, CA 94089 Email: schattopadhyay@infinera.com Harpreet Uppal Infinera 140 Caspian Ct., Sunnyvale, CA 94089 Email: harpreet.uppal@infinera.com Dhillon Expires April 2012 [Page 11]