One document matched: draft-douville-ccamp-gmpls-waveband-extensions-05.txt
Differences from draft-douville-ccamp-gmpls-waveband-extensions-04.txt
CCAMP Working Group Richard Douville
Internet Draft Dimitri Papadimitriou
Emmanuel Dotaro
Expires: January 2005 Alcatel
Rauf Izmailov
Aleksandar Kolarov
NEC
John Drake
Calient
July 2004
Extensions to Generalized Multi-Protocol Label Switching
in support of Waveband Switching
draft-douville-ccamp-gmpls-waveband-extensions-05.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026 [1].
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.
1. Abstract
Generalized Multi-Protocol Label Switching (GMPLS) extends the MPLS
control plane to encompass layer 2, time-division, wavelength and
spatial switching. Along with the current development on IP over
optical switching, considerable advances in optical transport
systems based on the multiple optical switching granularities have
been developed.
Currently, GMPLS considers two layers of optical granularity using
wavelengths and fibers. By introducing an extended definition of
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waveband switching, this document specifies the corresponding GMPLS
extensions, to further integrate optical multi-granularity and
benefit from the features of the corresponding switching layers.
2. Summary for Sub-IP Area
2.1. Summary
See the Abstract above.
2.2. Where does it fit in the Picture of the Sub-IP Work
This work fits the CCAMP box.
2.3. Why is it Targeted at this WG
This draft is targeted at the CCAMP WG, because it specifies the
extensions to the GMPLS signaling. GMPLS is itself addressed in the
CCAMP WG.
2.4. Justification of Work
The WG should consider this document as it specifies the extensions
to the GMPLS signaling. These extensions are related to the
definition of waveband switching and the introduction of optical
multi-granularity.
3. 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].
Other abbreviations and terminology in addition to the [GMPLS-ARCH],
[RFC3471] and [GMPLS-RTG] are:
WB LSP: WaveBand LSP
WBSC: WaveBand Switching Capable
WXC: Wavelength Cross-Connect
WBXC: WaveBand Cross-Connect
FXC: Fiber Cross-Connect
OXC: Optical Cross-Connect
PXC: Photonic Cross-Connect
4. Introduction
The optical multi-granularity concept relies on data plane
technologies working at the different switching layers (e.g.
wavelength, waveband and fiber). In the context of this memo, the
granularities considered inside optical networks are single
wavelengths (Lambda LSP), bundles of wavelengths referred to as
wavebands (WB LSP), and whole fibers (Fiber LSP). One of the key
benefits of multi-granularity is to simplify the switching
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procedures of multiple lower order LSPs (Lambda LSPs, for instance)
by switching these LSPs as a single entity at a higher order (e.g.
WB LSP or Fiber LSP). To enable such grouping of LSPs, several
grooming policies can be defined (either end-to-end or intermediate
or any combination). Details concerning these policies are out of
scope of the present document.
For this purpose, this memo extends the current set of Generalized
Multi-Protocol Label Switching (GMPLS) capabilities in the optical
domain (see [RFC3471]) by taking into account optical components
working at the waveband level. Within the set of optical multi-
granularity capabilities, three approaches to waveband switching
have been identified 1) Inverse Multiplexing 2) Wavelength
Concatenation and 3) Waveband Multiplexing/De-multiplexing.
The common availability of optical/photonic switching equipment
capable to work at the band level motivates the extension of the
definition of waveband switching as defined in the GMPLS
architecture. Current definition of waveband switching (see [GMPLS-
ARCH] and [RFC3471]) refers to inverse multiplexing mechanism or
wavelength concatenation ("contiguous" lambdas in a trunk defining a
logical waveband at the control plane level). While this definition
is still valid and applicable, it does not consider the approach
where wavebands have a physical significance, i.e. where the
interface is WaveBand-Switch Capable (WBSC). Physical waveband has
the ability to switch directly a portion of the frequency spectrum
without the need to distinguish between its inner components (e.g.
wavelengths or even below in certain known cases), this by using
waveband (de)/multiplexing components.
The following document groups the extensions to the GMPLS protocol
suite required to provide optical multi-granularity (distributed)
control and particularly the extensions required for waveband
switching support.
5. Extensions to the GMPLS Architecture and Protocol Suite
5.1. Architecture
The integration of optical multi-granularity in the GMPLS
architecture requires some extensions to the definitions it
currently includes.
The [GMPLS-ARCH] document considers waveband switching a particular
case of lambda switching. As specified, a waveband represents a set
of contiguous wavelengths, which can be switched together. This
definition of waveband is too restrictive at least on two key
aspects:
- The first one is that current definition of waveband implies a
wavelength composition of the waveband, due to waveband switching
by wavelength cross-connects (WXC). This definition provides
support to inverse multiplexing mechanism and wavelength
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concatenation. This approach limits the use of waveband to the
wavelength switch capable technologies. With waveband switching
technologies, the interface does not distinguish between the
component optical channels, sub-channels (i.e. timeslots) or
packets on the waveband which is switch as a single unit (wide
frequency spectrum) like it could be done with the fibers (the
penultimate frequency spectrum) on photonic cross-connect (PXC).
- The second restrictive point is that the current definition of the
waveband does not allow for intermediate grooming.
For this purpose, this memo introduces an additional optical
granularity representing the waveband. This definition is quite
general and backward compatible, it allows requesting a set of
contiguous wavelengths (i.e. inverse multiplexing mechanism and
wavelength concatenation) but also address the "real" waveband
switching and the corresponding set of capabilities. Therefore, the
proposed definition better fits into the whole GMPLS control plane
architecture.
Correspondingly, this memo specifies a new type of interface
switching capable interface: the Waveband-Switch Capable Interface
(WBSC). The WBSC interface materializes the physical reality of
optical waveband in the form of an atomic entity or granularity. As
with the introduction of the waveband switching capable interface, a
new class of LSP is defined: the WaveBand LSP (WB LSP).
The below figure illustrates the hierarchy of the (optical)
switching layers and highlights the optical multi-granularity part.
The switching element column shows typical (piece of) equipment that
can be part of the same node and thus simultaneously support such
interfaces.
LSP Hierarchy Interfaces Switching Element
------------- ---------- -----------------
Lambda LSP (1) <---> LSC <----> WXC -
|
WB LSP (1) <---> WBSC <----> WBXC > Optical MG
|
Fiber LSP <---> FSC <----> FXC -
(1) WB LSPs can be supported on both Lambda and WaveBand Switch
Capable interfaces depending on the nature of the waveband being
requested (inverse multiplexing, wavelength concatenation, or
physical waveband).
Note that this representation does not aim at restricting interfaces
that network elements can support.
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5.2 GMPLS Signalling
5.2.1 Generalized Label Request
To support Waveband LSP requests, the values of the LSP Encoding
Type, the Switching Type and the Generalized PID (G-PID) fields
included in the Generalized Label Request, are extended.
The information carried in a Generalized Label Request [RFC3471] is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LSP Enc. Type |Switching Type | G-PID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
LSP Encoding Type: 8 bits
Indicates the encoding of the LSP being requested. The
following Value 14 and Type Waveband (Photonic) is added to the
existing LSP Encoding Type values to provide Waveband LSP
support:
Value Type
----- ----
1 Packet
2 Ethernet
3 ANSI/ETSI PDH
4 Reserved
5 SDH ITU-T G.707 / SONET ANSI T1.105
6 Reserved
7 Digital Wrapper
8 Lambda (photonic)
9 Fiber
10 Reserved
11 FiberChannel
12 G.709 ODUk (Digital Path)
13 G.709 Optical Channel
14 Waveband (Photonic)
For example, consider an LSP signaled with "WaveBand" encoding.
It is expected that such an LSP would be supported with no
electrical conversion and no knowledge of the frequency
cutting, modulation and speed by the transit nodes. Other
formats normally require framing knowledge, and field
parameters are broken into the framing type and speed.
Switching Type: 8 bits
Indicates the type of switching that should be performed on a
particular link. This field is needed for links that advertise
more than one type of switching capability. For OXC or PXC
enabling Waveband switching, the WBSC value is used to refer to
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such switching capability. Other values of this field are as
the Switching Capability field defined in [GMPLS-RTG]
Generalized PID (G-PID): 16 bits
An identifier of the payload carried by an LSP, i.e. an
identifier of the client layer of that LSP. This is used by
the nodes at the endpoints of the LSP, and in some cases by the
penultimate hop. Standard Ethertype values are used for packet
and Ethernet LSPs; other values are defined in [RFC3471].
A waveband can carry a Lambda LSP while a Waveband LSP can be
transported on a Fiber LSP, the following additional G-PID
values must be considered: see [RFC3471] section 3.1.1 ¡
Required Information, paragraph on Generalized-PID
Value Type Technology
----- ---- ----------
58 Waveband Fiber
In addition the following existing values must be updated in
order to reflect the transport of Ethernet and SDH/SONET
payload over a waveband LSP:
33 Ethernet SDH, Lambda, Waveband, Fiber
34 SDH Lambda, Waveband, Fiber
35 Reserved None
36 Digital Wrapper Lambda, Waveband, Fiber
37 Lambda Waveband, Fiber
5.2.2 Generalized Label
In the present context, the waveband label space can make use of the
wavelength label format (see [RFC3471]) where each waveband is
uniquely identified, on a per node basis, by a Waveband Id (used as
label).
It is also assumed that a list of tuples of the form [Waveband Id,
<Local Wavelength Id, Remote Wavelength Id>, <..,..>] is maintained
on a local basis. The association between local and remote Waveband
Id's <Local Waveband Id, Remote Waveband Id> can be configured
either manually or dynamically using [LMP]. The association between
the <Local Wavelength Id[i], Remote Wavelength Id[i]> and the
Waveband Id[j] can be configured either manually (by configuration)
or dynamically using [LMP].
5.3. GMPLS Routing
5.3.1 Waveband Interface Switching Capability
A new WaveBand-Switch Capability (WBSC) value shall be defined to
identify and distinguish the associated switching capability of a
link [MPLS-HIER]. If the switching capability of a (TE) link is of
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type WBSC, it means that the node receiving data over this link
(fiber) can recognize and switch individual WaveBands on this link
(without distinguishing lambdas, channels or packets).
Values defined in [GMPLS-RTG] and the one defined in the present
context gives the following Interface Switching Capabilities list:
Packet-Switch Capable-1 (PSC-1)
Packet-Switch Capable-2 (PSC-2)
Packet-Switch Capable-3 (PSC-3)
Packet-Switch Capable-4 (PSC-4)
Layer-2 Switch Capable (L2SC)
Time-Division-Multiplex Capable (TDM)
Lambda-Switch Capable (LSC)
Waveband-Switch Capable (WBSC)
Fiber-Switch Capable (FSC)
Note that the node that is advertising a given link (i.e., the node
that is transmitting) has to know the switching capabilities at the
other end of the link (i.e., the receiving end of the link). One way
to accomplish this is through configuration. Other options to
accomplish this are outside the scope of this document.
In brief, if an interface is of type WBSC, it means that the node
receiving data over this interface can recognize and switch
wavebands (sets of contiguous lambdas) within the interface as a
unit (without distinguishing lambdas, sub-channels or packets). On
the other hand, an interface that allows for waveband switching
belongs (at least) to the WBSC type.
5.3.2. Interface Switching Capability Descriptor
The Interface Switching Capability Descriptor is defined in [GMPLS-
RTG] and format specified for OSPF and ISIS in [GMPLS-OSPF] and
[GMPLS-ISIS], respectively.
- For ISIS, the Interface Switching Capability Descriptor is a sub-
TLV (of Type 21) of the extended IS reachability TLV (of Type 22).
The length is the length of value field in octets.
- For OSPF, the Interface Switching Capability Descriptor is a sub-
TLV (of Type 15) of the Link TLV (of Type 2). The length is the
length of value field in octets.
A new value for the Switching Capability (Switching Cap) field is
defined here to identify Waveband-Switch Capable (WBSC) interfaces:
151 Waveband Switching Capable (WBSC)
In the Interface Switching Capability Descriptor (ISCD), when the
Switching Capability (Switching Cap) field contains the value for
WBSC, the technology specific information field includes the Minimum
LSP Bandwidth, which is defined as the minimum number of contiguous
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wavelength constituting a WaveBand entity. The Maximum LSP is simply
defined as the maximum number of contiguous wavelength that can
constitute a WaveBand entity. Additional technology specific
information MAY also be considered such as the channel spacing,
regeneration or conversion capabilities.
It is also expected here that the corresponding properties (for
instance, the number of wavelength supported per wavebands or
wavelength spacing) to be grouped and a dedicated Resource
Class/Color to be assigned to each of these groups allowing for a
more efficient path computation (using pruning).
5.4. LSP Regions and Forwarding Adjacencies
The information carried in the Switching Capability field (8 bits)
of the Interface Switching Capability Descriptor (ISCD) is used to
construct LSP regions, and determine regions' boundaries as defined
in [MPLS-HIER].
The introduction of the new WBSC Interface Switching Capability
define a new ordering among the switching capabilities: PSC-1 < PSC-
2 < PSC-3 < PSC-4 < L2SC < TDM < LSC < WBSC < FSC.
Path computation may take into account this WBSC region boundary
when computing a path for a LSP. When an LSP need to cross a region
boundary, it can trigger the establishment of a Forwarding Adjacency
LSP (FA-LSP) at the underlying layer. For instance, when a Lambda
LSP or a L2SC LSP needs to cross a WBSC region, it can trigger the
establishment of a Waveband FA-LSP or re-use an existing one if a
matching is found (see [MPLS-HIER]).
6. Security Considerations
No additional security considerations beyond the one covered in
[RFC3471]. Also, the routing extensions proposed in this document do
not raise any new security concerns.
7. Intellectual Property Considerations
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed
to pertain to the implementation or use of the technology
described in this document or the extent to which any license
under such rights might or might not be available; nor does it
represent that it has made any independent effort to identify any
such rights. Information on the procedures with respect to rights
in RFC documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use
of such proprietary rights by implementers or users of this
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specification can be obtained from the IETF on-line IPR repository
at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention
any copyrights, patents or patent applications, or other
proprietary rights that may cover technology that may be required
to implement this standard. Please address the information to the
IETF at ietf-ipr@ietf.org.
7.1 IPR Disclosure Acknowledgement
By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance with
[RFC3668].
8. References
8.1 Normative References
[GMPLS-ARCH] E.Mannie (Editor) et al., "Generalized Multi-Protocol
Label Switching (GMPLS) Architecture," Internet Draft,
Work in progress, draft-ietf-ccamp-gmpls-architecture-
07.txt, May 2003.
[GMPLS-OSPF] K.Kompella et al., "OSPF Extensions in Support of
Generalized MPLS," Internet Draft, Work in progress,
draft-ietf-ccamp-ospf-gmpls-extensions-12.txt, October
2003.
[GMPLS-RTG] K.Kompella et al., "Routing Extensions in Support of
Generalized MPLS," Internet Draft, Work in Progress,
draft-ietf-ccamp-gmpls-routing-09.txt, October 2003.
[LMP] J.P.Lang (Editor) et al. "Link Management Protocol
(LMP)," Internet Draft, Work in progress, draft-ietf-
ccamp-lmp-10.txt, October 2003.
[MPLS-BUNDLE] K.Kompella et al., "Link Bundling in MPLS Traffic
Engineering," Internet Draft, draft-ietf-mpls-bundle-
04.txt, August 2002.
[MPLS-HIER] K.Kompella et al., "LSP Hierarchy with MPLS TE,"
Internet Draft, Work in progress, draft-ietf-mpls-lsp-
hierarchy-08.txt, August 2002.
[RFC2026] S.Bradner, "The Internet Standards Process --
Revision 3", BCP 9, RFC 2026, October 1996.
[RFC2119] S.Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC3209] D.Awduche (Editor) et al., "RSVP-TE: Extensions to RSVP
for LSP Tunnels," RFC 3209, December 2001.
[RFC3471] L.Berger (Editor) et al., "Generalized Multi-Protocol
Label Switching (GMPLS) - Signaling Functional
Description," RFC 3471, January 2003.
[RFC3473] L.Berger (Editor) et al., "Generalized Multi-Protocol
Label Switching (GMPLS) Signaling ¡ Resource
ReserVation Protocol ¡ Traffic Engineering (RSVP-TE)
Extensions," RFC 3473, January 2003.
[RFC3630] D.Katz et al., "Traffic Engineering Extensions to
OSPF," RFC 3630, September 2003.
[RFC3667] S.Bradner, "IETF Rights in Contributions", BCP 78,
RFC 3667, February 2004.
[RFC3668] S.Bradner, Ed., "Intellectual Property Rights in IETF
Technology", BCP 79, RFC 3668, February 2004.
7.2 Informative References
[GMPLS-ISIS] K.Kompella et al., "IS-IS Extensions in Support of
Generalized MPLS," Internet Draft, Work in progress,
draft-ietf-isis-gmpls-extensions-16.txt, January 2003.
[RFC3784] H.Smit and T.Li, "IS-IS Extensions for Traffic
Engineering," RFC 3784, June 2003.
8. Author's Addresses
Richard Douville (Alcatel)
Route de Nozay, 91460 Marcoussis, France
Phone: +33 1 6963-4431
Email: richard.douville@alcatel.fr
Emmanuel Dotaro (Alcatel)
Route de Nozay, 91460 Marcoussis, France
Phone: +33 1 6963-4723
Email: emmanuel.dotaro@alcatel.fr
Dimitri Papadimitriou (Alcatel)
Fr. Wellesplein 1, B-2018 Antwerpen, Belgium
Phone: +32 3 240-8491
Email: dimitri.papadimitriou@alcatel.be
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Full Copyright Statement
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