One document matched: draft-zhang-ccamp-rwa-wson-routing-ospf-01.txt
Differences from draft-zhang-ccamp-rwa-wson-routing-ospf-00.txt
Network work group Fatai Zhang
Internet Draft Young Lee
Intended status: Standards Track Jianrui Han
Expires: January 2010 Huawei
G. Bernstein
Grotto Networking
Yunbin Xu
CATR
July 13, 2009
OSPF Extensions in Support of Routing and Wavelength
Assignment (RWA) in Wavelength Switched Optical Networks (WSONs)
draft-zhang-ccamp-rwa-wson-routing-ospf-01.txt
Status of this Memo
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This Internet-Draft will expire on January 13, 2010.
Abstract
This document describes OSPF routing protocols extensions to support
Routing and Wavelength Assignment (RWA) in Wavelength Switched
Optical Networks (WSON) under the control of Generalized MPLS (GMPLS).
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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 RFC-2119 [RFC2119].
Table of Contents
1. Introduction.................................................2
2. Node Information.............................................3
2.1. Connectivity Matrix.....................................4
2.2. Wavelength Converter Pool...............................4
2.2.1. Wavelength Converter Accessibility.................4
2.2.2. Wavelength Conversion Range........................5
2.2.3. WC Usage State.....................................5
3. Link Information.............................................5
3.1. WSON Port Wavelength Restrictions.......................6
3.2. Available Wavelengths...................................6
3.3. Shared Backup Wavelengths...............................6
4. Procedures for Routing Flooding..............................7
5. Security Considerations......................................7
6. IANA Considerations..........................................7
6.1. Node Information........................................8
6.2. Link Information........................................8
7. References...................................................8
8. Authors' Addresses...........................................11
Acknowledgment..................................................12
1. Introduction
Wavelength switched optical networks (WSONs) are based on Wavelength
Division Multiplexing (WDM) in which user traffic is carried by data
channels of different optical wavelengths. In traditional WDM
Networks, each wavelength path is statically configured. With the
deployment of Reconfigurable Optical Add-Drop Multiplexers (ROADMs),
photonic cross-connects (PXCs), and tunable laser, WSONs have become
more dynamic, and operators can flexibly set up wavelength paths to
carry user traffic.
In WSONs where there are no or a limited number of switches capable
of wavelength conversion paths must be set up subject to the
"wavelength continuity" constraint. This leads to a path computation
problem known as routing and wavelength assignment (RWA). In order to
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perform such computations, it is necessary to collect information
about the available wavelengths within the network.
[WSON-Frame] provides a framework for applying GMPLS [RFC3945] and
the Path Computation Element (PCE) architecture [RFC4655] to the
control of WSONs to address the RWA problem. [WSON-Info] describes an
information model that specifies the information needed at various
points in a WSON in order to compute paths and establish Label
Switched Paths (LSPs). Based on the information model of [WSON-Info],
[WSON-Encode] provides efficient protocol-independent encodings of
the information needed by the RWA process in a WSON. Such encodings
can be used to extend GMPLS signaling and routing protocols.
Therefore, in order to enable GMPLS to support Routing and Wavelength
Assignment (RWA) in Wavelength Switched Optical Networks (WSON)
networks, this document follows on from [WSON-Info], [WSON-Encode],
and [WSON-IGP-Eval] to define extensions to the OSPF routing protocol
to enhance the Traffic Engineering (TE) properties of GMPLS TE which
are defined in [RFC3630], [RFC4202], and [RFC4203]. The enhancements
to the Traffic Engineering (TE) properties of GMPLS TE links can be
announced in OSPF TE LSAs. The TE LSA, which is an opaque LSA with
area flooding scope [RFC3630], has only one top-level
Type/Length/Value (TLV) triplet and has one or more nested sub-TLVs
for extensibility. The top-level TLV can take one of three values (1)
Router Address [RFC3630], (2) Link [RFC3630], (3) Node Attribute
[OSPF-Node]. In this document, we enhance the sub-TLVs for the Link
TLV and Node Attribute TLV in support of RWA in WSON under the
control of GMPLS.
The detail encoding of OSPF extensions is not defined in this
document. [WSON-Encode] provides encoding detail.
No consideration of optical impairment routing related information is
included in this document.
2. Node Information
According to [WSON-Info] and [WSON-Encode], the node information
about WSON nodes includes Node ID, connectivity matrix, wavelength
converter pool information. Except for the Node ID which should
comply with Routing Address described in [RFC3630], the other pieces
of information are defined in this document.
[OSPF-Node] defines a new top TLV named the Node Attribute TLV which
carries attributes related to a router/node. This Node Attribute TLV
contains one or more sub-TLVs.
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From [WSON-Encode] we have identified the following new Sub-TLVs that
must be supported that can be nested under Node Attribute TLV. Detail
description for each newly defined Sub-TLV is provided in subsequent
sections:
Sub-TLV Type Length Name
TBD variable Connectivity Matrix
TBD variable Wavelength Converter Accessibility
TBD variable Wavelength Conversion Range
TBD variable WC Usage State
2.1. Connectivity Matrix
It is necessary to identify which ingress ports and wavelengths can
be connected to (the same wavelength on) a specific egress port,
because the switching devices in a WSON are highly asymmetric.
The Connectivity Matrix is used to identify these restrictions, which
can represent either the potential connectivity matrix for asymmetric
switches (e.g. ROADMs and such) or fixed connectivity for an
asymmetric device such as a multiplexer as defined in [WSON-Info].
The Connectivity Matrix is a sub-TLV (the type is TBD by IANA) of the
Node Attribute TLV. The length is the length of value field in octets.
The meaning and format of this sub-TLV are defined in [WSON-Info] and
[WSON-Encode]. One sub-TLV contains one matrix. The Connectivity
Matrix sub-TLV may occur more than once to contain multi-matrices
within the Node Attribute TLV.
2.2. Wavelength Converter Pool
A WSON node may include wavelength converters. The encoding of
structure and properties of a general wavelength converter pool
utilizes a converter accessibility sub-TLV, a wavelength converter
range sub-TLV, and a wavelength converter state sub-TLV as described
in [WSON-Encode].
2.2.1. Wavelength Converter Accessibility
Wavelength Converter Accessibility represents the ability of an
ingress port to reach a wavelength converter and of a wavelength
converter to reach a particular egress port as described in [WSON-
Encode].
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The Wavelength Converter Accessibility is a sub-TLV (the type is TBD
by IANA) of the Node Attribute TLV. The length is the length of value
field in octets. The meaning and format of this sub-TLV are defined
in [WSON-Info] and [WSON-Encode]. The Wavelength Converter
Accessibility sub-TLV may occur at most once within the Node
Attribute TLV.
2.2.2. Wavelength Conversion Range
Wavelength converters may have a limited input or output range which
can be described using one or more Wavelength Conversion Range sub-
TLV as described in [WSON-Encode].
The Wavelength Converter Range is a sub-TLV (the type is TBD by IANA)
of the Node Attribute TLV. The length is the length of value field in
octets. The meaning and format of this sub-TLV are defined in [WSON-
Info] and [WSON-Encode]. The Wavelength Converter Range sub-TLV may
occur more than once within the Node Attribute TLV.
2.2.3. WC Usage State
WC Usage Sate indicates the usage state of wavelength converters as
described in [WSON-Encode]
The WC Usage State is a sub-TLV (the type is TBD by IANA) of the Node
Attribute TLV. The length is the length of value field in octets. The
meaning and format of this sub-TLV are defined in [WSON-Info] and
[WSON-Encode]. The WC Usage State sub-TLV may occur at most once
within the Node Attribute TLV.
3. Link Information
The most common link sub-TLVs nested to link top-level TLV are
already defined in [RFC3630], [RFC4203]. For example, Link ID,
Administrative Group, Interface Switching Capability Descriptor
(ISCD), Link Protection Type, Shared Risk Link Group Information
(SRLG), and Traffic Engineering Metric are among the typical link
sub-TLVs.
For WSONs, per [WSON-Info] and [WSON-Encode], we add the following
additional link sub-TLVs to the link-TLV in this document.
Sub-TLV Type Length Name
TBD variable WSON Port Wavelength Restrictions
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TBD variable Available Wavelengths
TBD variable Shared Backup Wavelengths
3.1. WSON Port Wavelength Restrictions
Port Wavelength Restrictions describes the wavelength (label)
restrictions that the link and various optical devices such as OXCs,
ROADMs, and waveband multiplexers may impose on a port. These
restrictions represent what wavelength may or may not be used on a
link and are relatively static. The detailed information about Port
wavelength restrictions is described in [WSON-Info].
The WSON Port Wavelength Restrictions is a sub-TLV (the type is TBD
by IANA) of the Link TLV. The length is the length of value field in
octets. The meaning and format of this sub-TLV are defined in [WSON-
Info] and [WSON-Encode]. The WSON Port Wavelength Restrictions sub-
TLV may occur more than once to specify a complex port constraint
within the link TLV.
3.2. Available Wavelengths
Available Wavelengths indicates the wavelengths available for use on
a link as described in [RWA-Encode].The Available Wavelengths is a
sub-TLV (the type is TBD by IANA) of the Link TLV. The length is the
length of value field in octets. The meaning and format of this sub-
TLV are defined in [WSON-Info] and [WSON-Encode]. The Available
Wavelengths sub-TLV may occur at most once within the link TLV.
Note that there are five approaches for Wavelength Set which is used
to represent the Available Wavelengths described in [WSON-Encode].
Considering that the continuity of the available or unavailable
wavelength set can be scattered for the dynamic wavelength
availability, so it may burden the routing to reorganize the
wavelength set information when the Inclusive (/Exclusive) List
(/Range) approaches are used to represent Available Wavelengths
information. Therefore, it is RECOMMENDED that only the Bitmap Set be
used for representation Available Wavelengths information.
3.3. Shared Backup Wavelengths
Shared Backup Wavelengths indicates the wavelengths available for
shared backup use on a link as described in [RWA-Encode].
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The Shared Backup Wavelengths is a sub-TLV (the type is TBD by IANA)
of the Link TLV. The length is the length of value field in octets.
The meaning and format of this sub-TLV are defined in [WSON-Info] and
[WSON-Encode]. The Shared Backup Wavelengths sub-TLV may occur at
most once within the link TLV.
4. Procedures for Routing Flooding
All the sub-TLVs are nested to top-level TLV(s) and contained in
Opaque LSAs. The flooding of Opaque LSAs must follow the rules
specified in [RFC2328], [RFC2370], [RFC3630], [RFC4203], [OSPF-Node].
In the WSON networks, the node information and link information can
be classified as two kinds: one is relatively static information such
as Node ID, Connectivity Matrix information; the other is dynamic
information such as WC Usage State, Available Wavelengths information.
[WSON-Encode] give recommendations of typical usage of previously
defined sub-TLVs which contain relatively static information and
dynamic information. An implementation SHOULD take measures to avoid
frequent updates of relatively static information when the relatively
static information is not changed. A mechanism MAY be applied such
that static information and dynamic information are contained in
separate Opaque LSAs to avoid unnecessary updates of static
information when dynamic information is changed.
Note that as with other TE information, an implementation SHOULD take
measures to avoid rapid and frequent updates of routing information
that could cause the routing network to become swamped. A threshold
mechanism MAY be applied such that updates are only flooded when a
number of changes have been made to the wavelength availability
information within a specific time. Such mechanisms MUST be
configurable if they are implemented.
5. Security Considerations
This document does not introduce any further security issues other
than those discussed in [RFC 3630], [RFC 4203].
6. IANA Considerations
[RFC3630] says that the top level Types in a TE LSA and Types for
sub-TLVs for each top level Types must be assigned by Expert Review,
and must be registered with IANA.
IANA is requested to allocate new Types for the sub-TLVs as defined
in Sections 2.1, 2.2, 3.1, 3.2 and 3.3 as follows:
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6.1. Node Information
This document introduces the following sub-TLV of Node Attribute TLV
(Value TBD, see [OSPF-Node])
Type sub-TLV
TBD Connectivity Matrix
TBD Wavelength Converter Accessibility
TBD Wavelength Conversion Range
TBD WC Usage State
6.2. Link Information
This document introduces the following sub-TLV of TE Link TLV (Value
2)
Type sub-TLV
TBD WSON Port Wavelength Restrictions
TBD Available Wavelengths
TBD Shared Backup Wavelengths
7. References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471,
January 2003.
[RFC3630] Katz, D., Kompella, K., and Yeung, D., "Traffic
Engineering (TE) Extensions to OSPF Version 2", RFC
3630, September 2003.
[RFC4202] Kompella, K., Ed., and Y. Rekhter, Ed., "Routing Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4202, October 2005
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[RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, October 2005.
[RFC3945] E. Mannie, Ed., "OGeneralized Multi-Protocol Label Switching (GMPLS)
Architecture", RFC 3945, October 2004.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
Computation Element (PCE)-Based Architecture ", RFC 4655,
August 2006.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC2370] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, July
1998.
[OSPF-Node] R. Aggarwal and K. Kompella, "Advertising a Router's
Local Addresses in OSPF TE Extensions", draft-ietf-ospf-
te-node-addr, work in progress.
[Lambda-Labels] T. Otani, H. Guo, K. Miyazaki, D. Caviglia,
"Generalized Labels for G.694 Lambda-Switching
Capable Label Switching Routers", work in progress:
draft-ietf-ccamp-gmpls-g-694-lambda-labels-03.txt,
January 2009.
[WSON-Frame] G. Bernstein, Y. Lee, W. Imajuku, "Framework for GMPLS
and PCE Control of Wavelength Switched Optical
Networks", work in progress: draft-ietf-ccamp-rwa-WSON-
Framework-00.txt, December 2008.
[WSON-Info] Y. Lee, G. Bernstein, D. Li, W. Imajuku, "Routing and
Wavelength Assignment Information Model for Wavelength
Switched Optical Networks", work in progress: draft-ietf-
ccamp-rwa-info-01.txt, October 2008.
[WSON-Encode] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and
Wavelength Assignment Information Encoding for
Wavelength Switched Optical Networks", work in progress:
draft-ietf-ccamp-rwa-wson-encode-00.txt, December 2008.
[WSON-IGP-Eval] Dan Li, J. Gao, Y. Lee, "Evaluation of Possible
Interior Gateway Protocol Extensions for Wavelength
Switching Optical Networks", work in progress:
draft-li-ccamp-wson-igp-eval-01.txt, July 2008.
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[Switch] G. Bernstein, Y. Lee, A. Gavler, J. Martensson, " Modeling
WDM Wavelength Switching Systems for use in Automated Path
Computation", http://www.grotto-
networking.com/wson/ModelingWSONswitchesV2a.pdf , June,
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8. Authors' Addresses
Fatai Zhang
Huawei Technologies
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28972912
Email: zhangfatai@huawei.com
Young Lee
Huawei Technologies
1700 Alma Drive, Suite 100
Plano, TX 75075
USA
Phone: (972) 509-5599 (x2240)
Email: ylee@huawei.com
Jianrui Han
Huawei Technologies Co., Ltd.
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28972913
Email: hanjianrui@huawei.com
Greg Bernstein
Grotto Networking
Fremont CA, USA
Phone: (510) 573-2237
Email: gregb@grotto-networking.com
Yunbin Xu
China Academy of Telecommunication Research of MII
11 Yue Tan Nan Jie Beijing, P.R.China
Phone: +86-10-68094134
Email: xuyunbin@mail.ritt.com.cn
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Guoying Zhang
China Academy of Telecommunication Research of MII
11 Yue Tan Nan Jie Beijing, P.R.China
Phone: +86-10-68094272
Email: zhangguoying@mail.ritt.com.cn
Dan Li
Huawei Technologies Co., Ltd.
F3-5-B R&D Center, Huawei Base
Bantian, Longgang District
Shenzhen 518129 P.R.China
Phone: +86-755-28973237
Email: danli@huawei.com
Ming Chen
Huawei Technologies Deutschland GmbH
Riesstr. 25, 80992 Munchen, Germany
Phone: 0049-89158834072
Email: minc@huawei.com
Acknowledgment
TBD.
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