Internet Engineering Task Force D. Schroetter, Ed.
Internet-Draft G. Martinelli
Intended status: Standards Track Cisco Systems
Expires: September 2, 2010 March 1, 2010
OSPF Link Information Model for OSPF
draft-schroetter-wson-ospf-link-info-00
Abstract
This document describes the extensions to the OSPF Link TLV to
support Routing and Wavelength Assignment (RWA) in Wavelength
Switched Optical Networks (WSON) under the control of Generalized
MPLS (GMPLS).
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/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 September 2, 2010.
Copyright 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
Schroetter & Martinelli Expires September 2, 2010 [Page 1]
Internet-Draft OSPF Link Information for WSON March 2010
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 BSD License.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Schroetter & Martinelli Expires September 2, 2010 [Page 2]
Internet-Draft OSPF Link Information for WSON March 2010
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Client signals that require specific wavelengths on a
given link . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Wavelengths reserved for specific uses . . . . . . . . . . 5
2.3. Wavelength Availability based on adjacent channel usage . 6
3. Link Information . . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Sublink Wavelength Set sub-TLV . . . . . . . . . . . . . . 7
3.1.1. Label Set . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Sublink Modulation Format Compatibility Set . . . . . . . 10
3.3. Signal Dependency sub-TLV . . . . . . . . . . . . . . . . 11
3.4. Sublink Administrative Group sub-TLV . . . . . . . . . . . 13
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
5. Security Considerations . . . . . . . . . . . . . . . . . . . 14
Appendix A. Usage Examples . . . . . . . . . . . . . . . . . . . 14
Appendix A.1. Simple set of wavelengths . . . . . . . . . . . . . 14
Appendix A.2. Simple set of wavelengths with exclusions . . . . . 15
Appendix A.3. Multiple sublinks per link . . . . . . . . . . . . . 16
Appendix A.4. Sublink Modulation Format Compatibility Set . . . . 17
Appendix A.5. Signal Dependency Set . . . . . . . . . . . . . . . 18
6. Normative References . . . . . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
Schroetter & Martinelli Expires September 2, 2010 [Page 3]
Internet-Draft OSPF Link Information for WSON March 2010
1. Introduction
The current Internet Draft describing the Wavelength Switched Optical
Network (WSON) information model [I-D.ietf-ccamp-rwa-info] defines
the links in a WSON network with respect to their connectivity
matrix, their label restrictions (essentially the set of allowed or
usable wavelengths) and additional information from the MPLS-TE
routing protocol extensions for OSPF and IS-IS [RFC3630], [RFC5305]
along with the GMPLS routing protocols extensions for OSPF and IS-IS
[RFC4203], [RFC5307].
At a high level, the information models for WSON described in
[I-D.ietf-ccamp-rwa-info] and [WSON-Encode] model the connectivity
through the WSON switching node as well as the connectivity between
links at a WSON switching node. The current information model is
sufficient to describe the structure of a WSON node as well as the
possible interconnection of wavelengths between links and their local
processing (e.g. regeneration or wavelength conversion). This
document describes extensions to that model and their encoding that
allow a more granular approach to provide hints to the Routing and
Wavelength Assignment (RWA) algorithm regarding the placement of
client signals within a set of available wavelengths and a more
granular approach towards the association of channels or channel sets
with Administrative Groups.
1.1. Requirements Language
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].
2. Usage Scenarios
This section provides some usage scenarios of the proposed extension.
2.1. Client signals that require specific wavelengths on a given link
Assume a link between two nodes that can carry a specific client
signal type (identified by the modulation format of the client
signal) only on a specific subset of the supported wavelengths of
that link. This restriction may be due to the optical parameters of
the link or administrative preference of the operator.
In a setup as shown in Figure 1 the physical link may only support
40G on wavelength #3 (denoted as WL3). The document defines
extensions to the OSPF Link TLV that allow the logical partitioning
of the link into two sub-links. Hints to the Routing and Wavelength
Schroetter & Martinelli Expires September 2, 2010 [Page 4]
Internet-Draft OSPF Link Information for WSON March 2010
Assignment (RWA) algorithm on where to place a client signal using a
10G vs. 40G modulation format can then be provided through the use of
the Sublink Modulation Format Compatibility Set sub-TV (see
Section 3.2) and the Sublink Administrative Group sub-TLV (see
Section 3.4).
------------------------- ------+------------------
+------+ | +------+
L | WL 1 | L | | WL 1 |
+------+ | +------+
|
+------+ | +------+
I | WL 2 | I | | WL 2 | Sublink 1
+------+ | +------+ for 10G
|
+------+ | +------+
N | WL 3 | N | | WL 4 |
+------+ | +------+
+------------------
+------+ | +------+
K | WL 4 | K | | WL 3 | Sublink 2
+------+ | +------+ for 40G
------------------------- ------+------------------
Figure 1: 40G Client Signal may only be carried on WL3
2.2. Wavelengths reserved for specific uses
Assume a link between two nodes where the operator wants to reserve a
number of wavelengths for a specific purpose. Such purposes may
include these wavelengths being available to the RWA algorithm only
for backup purposes or being only available to client signals that
require wavelength conversion or regeneration. Such preferences and
restrictions on the usage of wavelengths can be described using the
Administrative Group concept when the Administrative Group is
associated with a sublink.
In a setup as shown in Figure 2 assume that wavelength #4 (WL4) may
only be used for 40G signals that belong to a specific Administrative
Group (AG=3 in this example). This restriction may be due to policy
choice by the operator or due to structural restrictions in the node
itself (e.g. access to wavelength converters). In such cases, the
hints to the Routing and Wavelength Assignment (RWA) algorithm on
where to place a client signal can then be provided through the use
of the Sublink Modulation Format Compatibility Set sub-TV (see
Section 3.2) and the Sublink Administrative Group sub-TLV (see
Section 3.4).
Schroetter & Martinelli Expires September 2, 2010 [Page 5]
Internet-Draft OSPF Link Information for WSON March 2010
------------------------- ------+------------------
+------+ | +------+
L | WL 1 | L | | WL 1 |
+------+ | +------+ Sublink 1
| for 10G
+------+ | +------+ with AG=1
I | WL 2 | I | | WL 2 |
+------+ | +------+
+------------------
+------+ | +------+
N | WL 3 | N | | WL 3 | Sublink 2
+------+ | +------+ for 40G AG=2
+------------------
+------+ | +------+
K | WL 4 | K | | WL 4 | Sublink 3
+------+ | +------+ for AG=3
------------------------- ------+------------------
Figure 2: Client Signal may only be carried on WL3
2.3. Wavelength Availability based on adjacent channel usage
In some cases the placement of a client signal may depend on the
modulation format of a signal in an adjacent channel or a client
signal of a specific set of modulation formats requires a number of
adjacent channels not to be in use. Assume a link that supports four
channels at a given channel spacing when using a 10G modulation
format. 40G signals are also supported, but the modulation format
requires or the operator mandates that the adjacent channels must not
be in use if a channel carries a 40G signal. Such dependencies can
be expressed using the Signal Dependency sub-TLV (see Section 3.3).
3. Link Information
The Link TLV describes a single link with respect to the available
bandwidth and any administrative or signal-related restrictions on
the wavelength use. It is constructed of a number of sub-TLVs which
may appear in the TLV in any order. The Link TLV MUST contain
exactly one Link Wavelength Set sub-TLV for each sublink. At least
one Wavelength Set sub-TLV MUST be present in the Link TLV. All
other sub-TLVs described in this document are OPTIONAL.
The following sub-TLVs of the Link TLV are defined:
TBD - Sublink Wavelength Set
Schroetter & Martinelli Expires September 2, 2010 [Page 6]
Internet-Draft OSPF Link Information for WSON March 2010
TBD - Sublink Modulation Format Compatibility Set
TBD - Signal Dependency Set
TBD - Sublink Administrative Group
This document introduces the concept of logical sublinks within a
physical link connecting two nodes. A sublink is uniquely identified
through the tuple (Link ID, Sublink ID). Sublink IDs MUST be unique
on a per-link basis.
The Link TLV can be represented through a RBNF in the following way:
<WSON_LINK_TLV> ::= [ <Sublink Definition> ]
Where the <Sublink Definition> consist of a variable set of sub-TLV
associated with a sublink.
<Sublink Definition> ::= <SL_WL_SET> [ <SL_WL_SET> ...]
[ <SL_FORMAT_COMPAT> ] [ <SL_SIGNAL_DEP> ]
[ <SL_ADMIN_GROUP> ]
The objects composing <Sublink Definition> are the sub-TLV defined
along this section.
3.1. Sublink Wavelength Set sub-TLV
The Link wavelength set sub-TLV specifies the wavelengths that this
link can support and any restrictions on the usage of these
wavelengths from administrative choice by the operator or signal
compatibility of the client signal with respect to a set of
wavelengths.
The Link wavelength sub-TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID | Encoding | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Wavelength Descriptor :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Sublink Wavelength Set sub-TLV
Schroetter & Martinelli Expires September 2, 2010 [Page 7]
Internet-Draft OSPF Link Information for WSON March 2010
Sublink ID: 8 bits
0x00 - Reserved
0x01 ... 0xFE - Sublink ID
Unique identifier for the wavelength set. This identifier
is unique on a per-link basis.
0xFF - reserved
Encoding: 8 bits
0x00 - Reserved
0x01 - Label Sets
Wavelength Set encoding based on Label Sets per
Section 3.1.1. The format of the labels follows
[I-D.ietf-ccamp-gmpls-g-694-lambda-labels].
0x02 - Label Bitset
Label Set encoding per []
0x03 ... 0xFF - reserved
Reserved: 16 bits
This field is reserved. It MUST be set to zero on transmission
and MUST be ignored on receipt.
Wavelength Descriptor: variable
The Wavelength Descriptor identifies the wavelengths being
available for this sublink. The format and length depends on
the encoding format.
If Encoding is 1 then at least one Label Set with Action set to 0 or
2 MUST be present in the Link Wavelength Set sub-TLV. There MAY be
multiple Label Sets per Link Wavelength Set sub-TLV. The set of
available channels on a (Link ID, Sublink ID) tuple is given by the
set complement of the union of all Label Sets with Action set to 0 or
2 and the union of all Label Sets with Action set to 1 or 3.
Schroetter & Martinelli Expires September 2, 2010 [Page 8]
Internet-Draft OSPF Link Information for WSON March 2010
3.1.1. Label Set
The encoding of the Label Sets is based on the similar concept
introduced in [RFC3471].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action | Reserved | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Wavelength 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: : :
: : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Wavelength N |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Label Set
Action : 8 bits
0 - Inclusive List
Indicates that the object contains one or more wavelength
elements that are included in the Label Set.
1 - Exclusive List
Indicates that the object contains one or more wavelength
elements that are excluded from the Label Set.
2 - Inclusive Range
Indicates that the object contains a range of labels that
are included in the Label Set. The object/TLV contains two
wavelength elements. The first element indicates the start
of the range. The second element indicates the end of the
range.
3 - Exclusive Range
Indicates that the object contains a range of labels that
are excluded from the Label Set. The object/TLV contains two
wavelength elements. The first element indicates the start
of the range. The second element indicates the end of the
range.
Schroetter & Martinelli Expires September 2, 2010 [Page 9]
Internet-Draft OSPF Link Information for WSON March 2010
Reserved: 8 bits
This field is reserved. It MUST be set to zero on transmission
and MUST be ignored on receipt.
Length: 16 bits
Length in octets of this Label Set
Wavelength: 32 bits
The wavelength represents the individual channel to be included
in or excluded from the list of available channels (if Action
is 0 or 1) or the start or end of the channel range (If Action
is 2 or 3). If Action is 2 or 3 exactly two wavelength entries
MUST be present. If Action is 0 or 1 there MUST be at least
one Wavelength element.
The encoding of the wavelength field follows
[I-D.ietf-ccamp-gmpls-g-694-lambda-labels]
3.2. Sublink Modulation Format Compatibility Set
The OPTIONAL Sublink Modulation Format Compatibility Set sub-TLV
carries the list of acceptable modulation formats for any wavelength
in the sublink.
The Wavelength Set Modulation Format Compatibility Set has the
following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID | Encoding | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Modulation Type 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Modulation Type N :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Sublink Modulation Format
Sublink ID: 8 bits
0x00 - Reserved
Schroetter & Martinelli Expires September 2, 2010 [Page 10]
Internet-Draft OSPF Link Information for WSON March 2010
0x01 ... 0xFE - Sublink ID
Unique identifier for the wavelength set. This identifier
is unique on a per-link basis.
0xFF - Reserved
Encoding: 8 bits
0x00 - Reserved
0x01 - Encoding using modulation type per [WSON-Encode].
0x02-0xFF - Reserved
Reserved: 16 bits
This field is reserved. It MUST be set to zero on transmission
and MUST be ignored on receipt.
Modulation Type 1..N: variable
List of acceptable modulation formats for the wavelengths in
this sublink per [WSON-Encode].
Currently, the only modulation format specification is the one
described in [WSON-Encode]. Additional encoding mechanisms for
signal compatibility may be defined in the future.
3.3. Signal Dependency sub-TLV
This OPTIONAL sub-TLV indicates a wavelength blocking of adjacent
wavelengths based upon the modulation format of a client signal
around that client signal's center wavelength. The Signal Dependency
sub-TLV has the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Modulation Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Grid | C.S | Lower Excursion |Grid | C.S | Upper Excursion |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Signal Dependency sub-TLV
Schroetter & Martinelli Expires September 2, 2010 [Page 11]
Internet-Draft OSPF Link Information for WSON March 2010
Modulation Type: variable
Specifies the modulation type for which wavelength blocking of
adjacent wavelengths around the client signal's center
frequency shall be used. The format of the Modulation Type
follows [WSON-Encode].
Grid: 3 bits
0 - Reserved
1 - ITU-T DWDM
2 - ITU-T CDWDM
3 .. 7 - Reserved
C.S (channel spacing): 4 bits
0 - Reserved
1 - 100 GHz
2 - 50 GHz
3 - 25 GHz
4 - 12.5 GHz
5 .. 15 - Reserved
Lower Excursion: 9 bits
Specifies the excursion from the client signal's center
wavelength towards the lower frequencies. For DWDM links the
lower boundary of the signal dependency wavelength range is
given by center frequency - Lower Excursion * Channel Spacing.
A value of 0 indicates no excursion towards the lower
frequencies.
Upper Excursion: 9 bits
Specifies the excursion from the client signal's center
wavelength towards the higher frequencies. For DWDM links the
upper boundary of the signal dependency wavelength range is
given by center frequency + Lower Excursion * Channel Spacing.
A value of 0 indicates no excursion towards the higher
frequencies.
Schroetter & Martinelli Expires September 2, 2010 [Page 12]
Internet-Draft OSPF Link Information for WSON March 2010
This optional sub-TLV defines a lambda range of
[Lower Excursion * Channel Spacing,Upper Excursion * Channel Spacing]
for DWDM and
[Lower Excursion * 20 nm,Upper Excursion * 20 nm] for CWDM
which can not be used around a signal's center wavelength or center
frequency if that signal uses the modulation format specified in the
sub-TLV.
3.4. Sublink Administrative Group sub-TLV
The OPTIONAL Administrative Group sub-TLV carries the Administrative
Group for the sublink identified in this sub-TLV. The sub-TlV has
the following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Administrative Group |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Administrative Group sub-TLV
Sublink ID: 8 bits
0x00 - Reserved
0x01 ... 0xFE - Sublink ID
Unique identifier for the wavelength set. This identifier
is unique on a per-link basis.
0xFF - reserved
Reserved: 24 bits
This field is reserved. It MUST be set to zero on transmission
and MUST be ignored on receipt.
Administrative Group: 32 bits
Schroetter & Martinelli Expires September 2, 2010 [Page 13]
Internet-Draft OSPF Link Information for WSON March 2010
This field contains the Administrative Group associated with
the identified Sublink ID. The format of this field is defined
in Section 2.5.9 of [RFC3630]
4. IANA Considerations
As per [RFC3630] all Type assignments for sub-TLVs need to be made
through IANA. This document requests Type assignments for the sub-
TLVs described in Section 3.
5. Security Considerations
This document does not introduce any further security issues above
and beyond those discussed in [RFC3630] and [RFC4203].
Appendix A. Usage Examples
The appendix shows some of the use cases of the Link Extensions
described in this document.
Appendix A.1. Simple set of wavelengths
This example shows the encoding for a WSON link carrying a single
sublink. The wavelengths available on this link are the channels at
the frequencies between 192.0 THz (1561.41 nm) and 195.9 THz (1530.33
nm) using 100 GHz grid spacing.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID= 1 | Encoding=1 | Reserved=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action=2 | Reserved=0 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = -11 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 28 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Link Wavelength Set sub-TLV Encoding Example
The encoding defines a sublink with the ID 1 and the encoding uses
Label Sets. The Label Set is specified using an inclusive Range
(Action=2). The next four octets specify the starting frequency of
the wavelength band using the DWDM Grid (G=1) and the grid spacing of
Schroetter & Martinelli Expires September 2, 2010 [Page 14]
Internet-Draft OSPF Link Information for WSON March 2010
100 GHz (C.S=1). The n field contains the offset in 100 GHz steps
from 193.1 THz ((192.0 - 193.1) / 0.1). The following four octets
encode the end frequency of the wavelength band in a similar manner.
Appendix A.2. Simple set of wavelengths with exclusions
This example shows the encoding for a WSON link carrying a single
sublink. The wavelengths available on this link are the channels at
the frequencies between 192.0 THz (1561.41 nm) and 195.9 THz (1530.33
nm) using 100 GHz grid spacing as before but the link uses a guard
channel at every fifth channel of the 100 GHz grid ("four-skip-one").
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID= 1 | Encoding=1 | Reserved=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action=2 | Reserved=0 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = -11 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 28 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action=1 | Reserved=0 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = -6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = -1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 14 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 19 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Link Wavelength Set sub-TLV Encoding Example with excluded
wavelengths
The base encoding follows the previous example, but this time a list
of excluded wavelengths (Action = 1) follows the definition of the
included range of wavelengths (Action=2). In this example the
wavelengths at the center frequencies of 192.5, 193.0, 193.5, 194.0,
194.5 and 195.5 THz are excluded from the list of available
Schroetter & Martinelli Expires September 2, 2010 [Page 15]
Internet-Draft OSPF Link Information for WSON March 2010
wavelengths for this sublink.
Appendix A.3. Multiple sublinks per link
An operator may want to logically subdivide the set of available
wavelengths for reasons of signal compatibility with only a specific
subset of wavelengths on a given link, general traffic conditioning
preferences or other policy choices. In order to allow the RWA
algorithm to honor such restrictions the link can be logically
subdivided into sublinks that may have different Modulation format
compatibility TLVs or Administrative Groups associated with them. In
this example, sublink 1 carries the channels with center frequencies
between 192.0 THz and 194.1 THz using a 50 GHz grid and sublink 2
contains the channels with center frequencies between 194.2 and 195.9
THz in a 100 GHz grid spacing. This change in grid spacing may be
due to signal compatibility when sublink 2 is used for LSPs using a
different modulation format than the ones using sublink 1.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID= 1 | Encoding=1 | Reserved=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action=2 | Reserved=0 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=2 | Reserved=0 | n = -22 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=2 | Reserved=0 | n = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Multiple Wavelength Sets per Link - Sublink 1
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID= 2 | Encoding=1 | Reserved=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action=2 | Reserved=0 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 11 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=1 | Reserved=0 | n = 28 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Multiple Wavelength Sets per Link - Sublink 2
Now that the channels logically belong to different sublinks, the
Schroetter & Martinelli Expires September 2, 2010 [Page 16]
Internet-Draft OSPF Link Information for WSON March 2010
Sublink Modulation Format Compatibility Set and Sublink
Administrative Group can be used to provide hints to the RWA
algorithm on which channels to consider for traffic using a specific
modulation format or requesting a specific Administrative Group.
Appendix A.4. Sublink Modulation Format Compatibility Set
After defining the two sublinks as per the previous example, one may
use the Sublink Modulation Format Compatibility Set TLV to provide
hints to the RWA algorithm that a specific client types using a set
of modulation formats should be use channels of a specific sublink.
In this example, the channels in sublink 1 can carry client signals
using the following modulation formats:
Optical Tributary Signal Class NRZ 2.5G
Optical Tributary Signal Class NRZ 10G
The corresponding encoding is 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID=1| Encoding=1 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|1| Modulation ID=2 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Possible additional modulation parameters depending upon |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: the modulation ID :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|1| Modulation ID=3 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Possible additional modulation parameters depending upon |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: the modulation ID :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Sublink Modulation Format - Sublink 1
Sublink 2 however should be used for the following modulation format:
Optical Tributary Signal Class NRZ 40G
Which is encoded as follows:
Schroetter & Martinelli Expires September 2, 2010 [Page 17]
Internet-Draft OSPF Link Information for WSON March 2010
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sublink ID=2| Encoding = 1 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|1| Modulation ID=4 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Possible additional modulation parameters depending upon |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: the modulation ID :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: Sublink Modulation Format - Sublink 2
Appendix A.5. Signal Dependency Set
In some cases a link may carry clients of a particular modulation
type at a Grid spacing of 50 GHz but it may require a different
spacing when a different modulation format is used. In that case a
channel at center frequency x "blocks" other frequencies around its
center frequency.
In this example, assume a sublink that can carry client signals at a
50 GHz spacing when the modulation format is "Optical Tributary
Signal Class NRZ 10G" and all channels can also carry client signals
using the "Optical Tributary Signal Class NRZ 40G" modulation format.
If a channel is using this modulation format, the two adjacent
channels may not be used. This information can be used by the RWA
algorithm to select the correct spacing of a new "Optical Tributary
Signal Class NRZ 40G" signal and mark its adjacent channels as
"unusable".
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|1| Modulation ID=4 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Possible additional modulation parameters depending upon |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: the modulation ID :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G=1 | C.S=2 | Lower Exc=1 | G=1 | C.S=2 | Upper Exc=1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 14: Signal Dependency sub-TLV Example
Schroetter & Martinelli Expires September 2, 2010 [Page 18]
Internet-Draft OSPF Link Information for WSON March 2010
6. Normative References
[G.694.1] "Spectral Grids for DWDM applications: DWDM frequency
grid", ITU-T Recommendation G.694.1, June 2002, <ITU-T
G.694.2>.
[I-D.ietf-ccamp-gmpls-g-694-lambda-labels]
Otani, T., Tsuritani, T., Li, D., Rabbat, R., Shiba, S.,
Guo, H., Miyazaki, K., and D. Caviglia, "Generalized
Labels for Lambda-Switching Capable Label Switching
Routers", draft-ietf-ccamp-gmpls-g-694-lambda-labels-05
(work in progress), December 2009.
[I-D.ietf-ccamp-rwa-info]
Bernstein, G., Lee, Y., Li, D., and W. Imajuku, "Routing
and Wavelength Assignment Information Model for Wavelength
Switched Optical Networks", draft-ietf-ccamp-rwa-info-07
(work in progress), February 2010.
[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 D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
September 2003.
[RFC4203] Kompella, K. and Y. Rekhter, "OSPF Extensions in Support
of Generalized Multi-Protocol Label Switching (GMPLS)",
RFC 4203, October 2005.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008.
[RFC5307] Kompella, K. and Y. Rekhter, "IS-IS Extensions in Support
of Generalized Multi-Protocol Label Switching (GMPLS)",
RFC 5307, October 2008.
[WSON-Encode]
Bernstein, G., Lee, Y., Li, D., and W. Imajuku, "Routing
and Wavelength Assignment Information Encoding for
Wavelength Switched Optical Networks", February 2010, <htt
ps://datatracker.ietf.org/doc/
draft-ietf-ccamp-rwa-wson-encode/>.
Schroetter & Martinelli Expires September 2, 2010 [Page 19]
Internet-Draft OSPF Link Information for WSON March 2010
Authors' Addresses
Dirk Schroetter (editor)
Cisco Systems
Neuer Wall 77
Hamburg, D-20354
Germany
Phone: +49 40 3767-4402
Email: dschroet@cisco.com
Giovanni Martinelli
Cisco Systems
Via Philips 12
Monza, 20052
Italy
Phone: +39 039 209-2044
Email: giomarti@cisco.com
Schroetter & Martinelli Expires September 2, 2010 [Page 20]