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."
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 April 31, 2012.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
Dhillon Expires April 2012 [Page 1]
Internet-Draft Super-Channel-Switching-Cap October 2011
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.
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
<Add any 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
<Add any acknowledgements>
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]