wdiff rfc8363.original rfc8363.txt

CCAMP Working Group Xian
Internet Engineering Task Force (IETF) X. Zhang
Internet-Draft Haomian
Request for Comments: 8363 H. Zheng
Intended status:
Category: Standards Track Huawei
Ramon
ISSN: 2070-1721 R. Casellas
CTTC
O. Gonzalez de Dios
Telefonica
D. Ceccarelli
Ericsson
Expires: August 17, 2017 February 17, 2017
May 2018

GMPLS OSPF-TE Extensions in support Support of Flexi-grid DWDM networks

draft-ietf-ccamp-flexible-grid-ospf-ext-09.txt Flexi-Grid
Dense Wavelength Division Multiplexing (DWDM) Networks

Abstract

The International Telecommunication Union Telecommunication
Standardization Sector
standardization sector (ITU-T) has extended its Recommendations
G.694.1 and G.872 to include a new Dense Wavelength Division
Multiplexing (DWDM) grid by defining channel spacings, a set of
nominal central frequencies, channel spacings, and the concept of the "frequency slot".
Corresponding techniques for data-plane connections are known as flexi-grid.
"flexi-grid".

Based on the characteristics of flexi-grid defined in G.694.1, RFC G.694.1 and in
RFCs 7698 and 7699, this document describes the OSPF-TE Open Shortest Path
First - Traffic Engineering (OSPF-TE) extensions in support of GMPLS
control of networks that include devices that use the new flexible
optical grid.

Status of this 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 an Internet Standards Track document.

This document is a product 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
(IETF). It represents the consensus of six
months the IETF community. It has
received public review and may be updated, replaced, or obsoleted has been approved for publication by other documents
at any time. It the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is inappropriate to use Internet-Drafts as
reference material or to cite them other than as "work available in progress."
The list Section 2 of RFC 7841.

Information about the current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.

The list status of Internet-Draft Shadow Directories can this document, any errata,
and how to provide feedback on it may be accessed obtained at
http://www.ietf.org/shadow.html.

This Internet-Draft will expire on August 17, 2017.
https://www.rfc-editor.org/info/rfc8363.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info)
(https://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 ................................................. . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology .................................................. . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Conventions Used in this This Document ....................... . . . . . . . . . . . . 4
3. Requirements for Flexi-grid Flexi-Grid Routing .......................... . . . . . . . . . . . . . 4
3.1. Available Frequency Ranges .............................. . . . . . . . . . . . . . . . 4
3.2. Application Compliance Considerations ................... . . . . . . . . . . 5
3.3. Comparison with Fixed-grid Fixed-Grid DWDM Links ................... . . . . . . . . . . 6
4. Extensions ................................................... . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. ISCD Interface Switching Capability Descriptor (ISCD)
Extensions for Flexi-grid .......................... Flexi-Grid . . . . . . . . . . . . . . . . 7
4.1.1. Switching Capability Specific Information (SCSI).... (SCSI) . . 8
4.1.2. An SCSI Example ................................... . . . . . . . . . . . . . . . . . . . 10
4.2. Extensions to the Port Label Restriction sub-TLV ........... 12 Restrictions Field . . . . . 11
5. IANA Considerations ......................................... . . . . . . . . . . . . . . . . . . . . . 13
5.1. New ISCD Switching Type ..................................... . . . . . . . . . . . . . . . . . 13
5.2. New Sub-TLV ............................................ SCSI Type . . . . . . . . . . . . . . . . . . . . . . 13
6. Implementation Status ....................................... 14
6.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)14
7. Acknowledgments ............................................. 15
8. Security Considerations ..................................... 15
9. Contributors' Addresses ..................................... 16
10. . . . . . . . . . . . . . . . . . . . 13
7. References ................................................. 16
10.1. . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1. Normative References .................................. 16
10.2. . . . . . . . . . . . . . . . . . . 14
7.2. Informative References ................................ 17 . . . . . . . . . . . . . . . . . 15
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Authors' Addresses ............................................. . . . . . . . . . . . . . . . . . . . . . . . 17

1. Introduction

[G.694.1] defines the Dense Wavelength Division Multiplexing (DWDM)
frequency grids for Wavelength Division Multiplexing (WDM)
applications. A frequency grid is a reference set of frequencies
used to denote allowed nominal central frequencies that may be used
for defining applications. The channel spacing is the frequency
spacing between two allowed nominal central frequencies. All of the
wavelengths on a fiber should use different central frequencies and
occupy a fixed bandwidth of frequency.

Fixed grid

Fixed-grid channel spacing ranges from one of 12.5 GHz, 25 GHz, 50
GHz, or 100 GHz to integer multiples of 100 GHz. But [G.694.1] also
defines a "flexible grids", grid", also known as "flexi-grid". The terms
"frequency slot" (i.e., the frequency range allocated to a specific
channel and unavailable to other channels within a flexible grid) and
"slot width" (i.e., the full width of a frequency slot in a flexible
grid) are used to define a flexible grid.

[RFC7698] defines a framework and the associated control plane control-plane
requirements for the GMPLS based GMPLS-based control of flexi-grid DWDM networks.

[RFC6163] provides a framework for GMPLS and Path Computation Element
(PCE) control of Wavelength Switched Optical Networks
(WSONs), and (WSONs).
[RFC7688] defines the requirements and OSPF-TE extensions in support
of GMPLS control of a WSON.

[RFC7792] describes requirements and protocol extensions for
signaling to set up LSPs Label Switched Paths (LSPs) in networks that
support the flexi-grid,
and this flexi-grid. This document complements [RFC7792] by
describing the requirement and extensions for OSPF-TE routing in a
flexi-grid network.

This document complements the efforts to provide extensions to Open
Short Path First (OSPF) Traffic-Engineering (TE) the
OSPF-TE protocol so as to support GMPLS control of flexi-grid
networks.

2. Terminology

For terminology related to flexi-grid, please consult [RFC7698] and
[G.694.1].

2.1. Conventions Used in this This Document

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC-2119 [RFC2119].
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.

3. Requirements for Flexi-grid Flexi-Grid Routing

The architecture for establishing LSPs in a Spectrum Switched
optical Optical
Network (SSON) is described in [RFC7698].

A flexi-grid LSP occupies a one or multiple specific frequency slot, i.e., a
frequency range. slots.
The process of computing a route and the allocation of a frequency
slot is referred to as RSA "RSA" (Routing and Spectrum Assignment).
[RFC7698] describes three types of architectural approaches to RSA:
combined RSA, separated RSA, and routing and distributed SA. The
first two approaches among them could be called "centralized SA" because the
spectrum (frequency slot) assignment is performed by a single entity
before the signaling procedure.

In the case of centralized SA, the assigned frequency slot is
specified in the RSVP-TE Path message during the signaling process.
In the case of routing and distributed SA, only the requested slot
width of the flexi-grid LSP is specified in the Path message,
allowing the involved network elements to select the frequency slot
to be used.

If the capability of switching or converting the whole optical
spectrum allocated to an optical spectrum LSP is not available at
nodes along the path of the LSP, the LSP is subject to the Optical
"Spectrum Continuity Constraint", as described in [RFC7698].

The remainder of this section states the additional extensions on the
routing protocols in a flexi-grid network.

3.1. Available Frequency Ranges

In the case of flexi-grids, the central frequency steps from 193.1
THz with 6.25 GHz granularity. The calculation method of central
frequency and the frequency slot width of a frequency slot are
defined in [G.694.1], i.e., by using nominal central frequency n and
the slot width m.

On a DWDM link, the allocated or in-use frequency slots do not
overlap with each other. However, the border frequencies of two
frequency slots may be the same frequency, i.e., the upper bound of a
frequency slot and the lower bound of the directly adjacent frequency
slot are the same.

Frequency Slot 1 Frequency Slot 2
+-----------+-----------------------+
| | |
-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
...+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--...
------------ ------------------------
^ ^
Central F = 193.1THz 193.1 THz Central F = 193.1375 THz
Slot width = 25 GHz Slot width = 50 GHz

Figure 1 - 1: Two Frequency Slots on a Link

Figure 1 shows two adjacent frequency slots on a link. The highest
frequency of frequency slot 1 denoted by n=2 is the lowest frequency
of slot 2. In this example, it means that the frequency range from
n=-2 to n=10 is unavailable to other flexi-grid LSPs. Available
central frequencies are advertised for m=1, which means that for an
available central frequency n, the frequency slot from central
frequency n-1 to central frequency n+1 is available.

Hence, in order to clearly show which LSPs frequency slots are available
and can be supported used for LSP establishment and what which frequency slots are
unavailable, the available availability of frequency ranges are
advertised slots is advertised by the
routing protocol for the flexi-grid DWDM links. A set of non-overlapping non-
overlapping available frequency ranges are is disseminated in order to
allow efficient resource management of flexi-grid DWDM links and RSA procedures
procedures, which are described in Section 4.8 of [RFC7698].

3.2. Application Compliance Considerations

As described in [G.694.1], devices or applications that make use of
the flexi-grid may not be capable of supporting every possible slot
width or position (i.e., central frequency). In other words,
applications or implementations may be defined where only a subset of
the possible slot widths and positions are required to be supported.

For example, an application could be defined where the nominal
central frequency granularity is 12.5 GHz (by only requiring values
of n that are even) and that the same application only requires slot
widths as a multiple of 25 GHz (by only requiring values of m that
are even).

Hence, in order to support all possible applications and
implementations
implementations, the following information SHOULD be advertised for a
flexi-grid DWDM link:

o Channel Spacing (C.S.): as defined in [RFC7699] for flexi-grid, is
set to 5 to denote 6.25GHz. 6.25 GHz.

o Central frequency granularity: a multiplier of C.S.. C.S.

o Slot width granularity: a multiplier of 2*C.S.. 2*C.S.

o Slot width range: two multipliers of the slot width granularity,
each indicate indicating the minimal and maximal slot width supported by a
port
port, respectively.

The combination of slot width range and slot width granularity can be
used to determine the slot widths set supported by a port.

3.3. Comparison with Fixed-grid Fixed-Grid DWDM Links

In the case of fixed-grid DWDM links, each wavelength has a pre-
defined
predefined central frequency and each frequency. Each wavelength maps to a pre-defined predefined
central frequency frequency, and the usable frequency range is implicit by the
channel spacing. All the wavelengths on a DWDM link can be
identified with an identifier that mainly conveys its central
frequency as the label defined in [RFC6205], and [RFC6205]; the status of the
wavelengths (available or not) can be advertised through a routing
protocol.

Figure 2 shows a link that supports a fixed-grid with 50 GHz channel
spacing. The central frequencies of the wavelengths are pre-defined predefined
by values of "n" "n", and each wavelength occupies a fixed 50 GHz
frequency range as described in [G.694.1].

W(-2) | W(-1) | W(0) | W(1) | W(2) |
...---------+-----------+-----------+-----------+-----------+----...
| 50 GHz | 50 GHz | 50 GHz | 50 GHz |

n=-2 n=-1 n=0 n=1 n=2
...---+-----------+-----------+-----------+-----------+----------...
^
Central F = 193.1THz 193.1 THz

Figure 2 - 2: A Link Supports Fixed Wavelengths
with 50 GHz Channel Spacing
Unlike the fixed-grid DWDM links, on a flexi-grid DWDM link link, the slot
width of the frequency slot is flexible flexible, as described in section Section 3.1.
That is, the value of m in the following formula from [G.694.1] is
uncertain before a frequency slot is actually allocated for a flexi-
grid LSP.

Slot Width (GHz) (in GHz) = 12.5GHz * m

For this reason, the available frequency slot/ranges slots (or ranges) are
advertised for a flexi-grid DWDM link instead of the specific "wavelengths"
"wavelength" points that are sufficient for a fixed-grid link.
Moreover, this advertisement is represented by the combination of Central Frequency
Granularity
central frequency granularity and Slot Width Granularity. slot width granularity.

4. Extensions

As described in [RFC7698], the network connectivity

The network-connectivity topology constructed by the links/nodes links and/or
nodes and node capabilities are the same as for WSON, as described in
[RFC7698], and they can be advertised by the GMPLS routing protocols
using
opaque LSAs Opaque Link State Advertisements (LSAs) [RFC3630] in the case
of OSPF-TE [RFC4203] (refer to
section Section 6.2 of [RFC6163]). In the
flexi-grid case, the available frequency ranges ranges, instead of the
specific "wavelengths" "wavelengths", are advertised for the link. This section
defines the GMPLS OSPF-TE extensions in support of advertising the
available frequency ranges for flexi-grid DWDM links.

4.1. ISCD Interface Switching Capability Descriptor (ISCD) Extensions for Flexi-grid
Flexi-Grid

This section defines a new value for the Switching Capability field
of the ISCD with a value of 152 and type name Flexi-Grid-LSC.

Value Type Name
----- ---- --------------
152 (TBA by IANA) Flexi-Grid-LSC

Switching Capability and Encoding values MUST be used as follows:

Switching Capability = Flexi-Grid-LSC

Encoding Type = lambda [as (as defined in RFC3471] [RFC3471])

When the Switching Capability and Encoding fields are set to values
as stated above, the Interface Switching Capability Descriptor ISCD is interpreted as in [RFC4203] with the
optional inclusion of one or more Switching Capability Specific
Information (SCSI) sub-TLVs.

As the "Max LSP Bandwidth at priority x" (x from 0 to 7) fields in
the generic part of the Interface Switching Capability Descriptor ISCD [RFC4203] are not meaningful for flexi-grid flexi-
grid DWDM links, the values of these fields MUST be set to zero and
MUST be ignored. The
Switching Capability Specific Information (SCSI) SCSI as defined below provides the
corresponding information for flexi-grid DWDM links.

4.1.1. Switching Capability Specific Information (SCSI)

[RFC8258] defines a Generalized SCSI for the ISCD. This document
defines the Frequency Availability Bitmap as a new type of the
Generalized SCSI TLV. The technology specific technology-specific part of the Flexi-grid flexi-grid
ISCD includes the available frequency spectrum frequency-spectrum resource as well as
the information regarding max slot widths per priority information. priority. The format
of this flex-grid flexi-grid SCSI, the
frequency available bitmap TLV, Frequency Availability Bitmap sub-TLV,
is depicted in the following figure:

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 11 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Priority | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Max Slot Width at Priority k | Unreserved padding Padding ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| C.S. | Starting n | No. of Effective. Bits| Effective Bits |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bit Map Bitmap ... ~
~ ... | padding bits ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Type (16 bits): The type of this sub-TLV and is set to 1. (11).

Length (16 bits): The length of the value field of this sub-TLV, sub-TLV in
octets.

Priority (8 bits): A bitmap used to indicate which priorities are
being advertised. The bitmap is in ascending order, with the
leftmost bit representing priority level 0 (i.e., the highest) and
the rightmost bit representing priority level 7 (i.e., the lowest).
A bit is set (1) corresponding to each priority represented in the sub-TLV,
sub-TLV and clear (0) for each priority not represented in the sub-TLV. sub-
TLV. At least one priority level MUST be advertised. If only one
priority level is advertised, it MUST be at priority level 0.

Reserved: The Reserved field MUST be set to zero on transmission and
MUST be ignored on receipt.

Max Slot Width at priority k(16 Priority k (16 bits): This field indicates maximal
frequency slot width supported at a particular priority level, up to
8. This field is set to max frequency slot width supported in the
unit of 2*C.S., for a particular priority level. One field MUST be
present for each bit set in the Priority field, and each present
field is ordered to match the Priority field. Fields MUST be present
for priority levels that are indicated in the Priority field.

Unreserved Padding (16 bits): The Padding field is used to ensure the 32 bit
32-bit alignment of Max Slot Width fields. at Priority k. When the
number of priorities k is odd, an odd
number, the Unreserved Padding field MUST be included. When the number of priorities k is even, an
even number, the Unreserved Padding field MUST be omitted. This
field MUST be set to 0 and MUST be ignored on receipt.

C.S. (4 bits): As defined in [RFC7699] and [RFC7699]; it is currently set to 5.

Starting n (16 bits): as As defined in [RFC7699] and this [RFC7699]. This value denotes
the starting point of the nominal central frequency point of the frequency
availability bitmap sub-TLV.

Number

No. of Effective Bits (12 bits): Indicates the number of effective
bits in the Bit Map Bitmap field.

Bit Map

Bitmap (variable): Indicates whether or not a basic frequency slot,
characterized by a nominal central frequency and a fixed m value of
1, is available or not for flexi-grid LSP setup. The first nominal central
frequency is the value of starting n and with the n; subsequent
ones nominal central
frequencies are implied by the position in the bitmap. Note that when
setting to 1, it means 1 indicates that the corresponding central frequency is
available for a flexi-grid LSP with m=1; m=1 and when setting to 0, it means 0 indicates
the corresponding central frequency is unavailable. Note that a
centralized SA process will need to extend this to high values of m
by checking a sufficient sufficiently large number of consecutive basic
frequency slots that are available.

Padding Bits

padding bits (variable): Padded after the Bit Map Bitmap to make it a
multiple of four bytes bytes, if necessary. Padding bits MUST be set to 0
and MUST be ignored on receipt.

An example is provided in section Section 4.1.2.

4.1.2. An SCSI Example

Figure 3 shows an example of the available frequency spectrum
resource of a flexi-grid DWDM link.

-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11
...+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--...
|--Available Frequency Range--|

Figure 3 - Flexi-grid 3: Flexi-Grid DWDM Link Example

The symbol "+" represents the allowed nominal central frequency. The
symbol "--" represents a central frequency granularity of 6.25 GHz,
as
which is currently be standardized in [G.694.1]. The number on the top
of the line represents the "n" in the frequency calculation formula
(193.1 + n * 0.00625). The nominal central frequency is 193.1 THz
when n equals zero.

In this example, it is assumed that the lowest nominal central
frequency supported is n= -9 n=-9 and the highest is n=11. Note they
cannot be used as a nominal central frequency for setting up a an LSP,
but merely as the way to express the supported frequency range.
Using the encoding defined in Section 4.1.1, the relevant fields to
express the frequency resource availability can be filled as 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 1 11 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Priority | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Max Slot Width at Priority k | Unreserved padding Padding ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 5 | Starting n (-9) | No. of Effec. Bits(21)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0|0|0|0|0|0|0|1|1|1|1|1|1|1|1|1|0|0|0|0| padding bits (0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

In the above example, the starting n is selected to be the lowest
nominal central frequency, i.e. i.e., -9. It is observed from the bit map bitmap
that n = -1 n=-1 to 7 can be used to set up LSPs. Note other starting n
values can be chosen to represent the bit map, bitmap; for example, the first
available nominal central frequency (a.k.a., the first available
basic frequency slot) can be chosen chosen, and the SCSI will be expressed
as the following:

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 11 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Priority | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Max Slot Width at Priority k | Unreserved padding Padding ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 5 | Starting n (-1) | No. of Effec. Bits(9)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1|1|1|1|1|1|1|1|1| padding bits (0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

This encoding denotes that that, other than the advertised available
nominal central frequencies, the other nominal central frequencies
within the whole frequency range supported by the link are not
available for flexi-grid LSP set up. setup.

If a an LSP with slot width m equals equal to 1 is set up using this link, say
using n= -1, n=-1, then the SCSI information is updated to be the following:

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 11 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Priority | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Max Slot Width at Priority k | Unreserved padding Padding ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 5 | Starting n (-1) | No. of Effec. Bits(9)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0|1|1|1|1|1|1|1| padding bits (0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

4.2. Extensions to the Port Label Restriction sub-TLV Restrictions Field

As described in Section 3.2, a port that supports flexi-grid may
support only a restricted subset of the full flexible grid. The Port
Label Restriction Restrictions field is defined in [RFC7579]. It can be used to
describe the label restrictions on a port and is carried in the top-level top-
level Link TLV as specified in [RFC7580]. A new restriction type,
the flexi-grid Restriction Type, is defined here to specify the
restrictions on a port to support flexi-grid.

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MatrixID | RstType = 5 | Switching Cap | Encoding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| C.S. | C.F.G | S.W.G | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Min Slot Width | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

MatrixID (8 bits): As defined in [RFC7579].

RstType (Restriction Type, 8 bits): Takes the value of 5 to indicate
the restrictions on a port to support flexi-grid.

Switching Cap (Switching Capability, 8 bits): As defined in
[RFC7579], MUST be consistent with the one specified in ISCD as
described in Section 4.1.

Encoding (8 bits): As defined in [RFC7579], MUST be consistent with
the one specified in ISCD as described in Section 4.1.

C.S. (4 bits): As defined in [RFC7699] and for flexi-grid [RFC7699]. For flexi-grid, it is 5 to
denote 6.25GHz. 6.25 GHz.

C.F.G (Central Frequency Granularity, 8 bits): A positive integer.
Its value indicates the multiple of C.S., in terms of central
frequency granularity.

S.W.G (Slot Width Granularity, 8 bits): A positive integer. Its
value indicates the multiple of 2*C.S., in terms of slot width
granularity.

Min Slot Width (16 bits): A positive integer. Its value indicates
the multiple of 2*C.S. (GHz), (in GHz), in terms of the supported minimal
slot width.

Reserved: The Reserved field MUST be set to zero on transmission and
SHOULD be ignored on receipt.

5. IANA Considerations

5.1. New ISCD Switching Type

Upon approval of this document,

IANA will make has made the following assignment in the "Switching Types" section sub-
registry of the "GMPLS "Generalized Multi-Protocol Label Switching (GMPLS)
Signaling Parameters" registry located at http://www.iana.org/assignments/gmpls-sig-
parameters:
<https://www.iana.org/assignments/gmpls-sig-parameters>:

Value Name Reference

--------- --------------------------
------- ---------------- ----------
152 (*) Flexi-Grid-LSC [This.I-D]

(*) Suggested value RFC 8363

5.2. New Sub-TLV SCSI Type

This document defines one a new generalized SCSI sub-TLV that are is carried
in the Interface Switching Capability Descriptors [RFC4203] with Signal when the
Switching Type is set to Flexi-Grid-LSC.

Upon approval of this document,

IANA will create and maintain a new
sub-registry, has made the "Types for sub-TLVs of Flexi-Grid-LSC SCSI (Switch
Capability-Specific Information)" registry under following assignment in the "Open Shortest
Path First (OSPF) Traffic Engineering TLVs" registry, see
http://www.iana.org/assignments/ospf-traffic-eng-tlvs/ospf-traffic-
eng-tlvs.xml, with "Generalized SCSI
(Switching Capability Specific Information) TLV Types" sub-registry
[RFC8258] of the sub-TLV types as follows:

This document defines new sub-TLV types as follows: "Generalized Multi-Protocol Label Switching (GMPLS)
Signaling Parameters" registry located at
<https://www.iana.org/assignments/gmpls-sig-parameters>:

Value Sub-TLV SCSI-TLV Switching Type Reference
----- ----------------------------- -------------- --------- -------------------------- ----------
0 Reserved [This.I-D]
1
11 Frequency availability bitmap [This.I-D] Availability Bitmap 152 RFC 8363

6. Implementation Status

[RFC Editor Note: Please remove this entire section prior to
publication as an RFC.] Security Considerations

This section records the status of known implementations of the
protocol defined by this specification at the time of posting of
this Internet-Draft, document extends [RFC4203] and is based on a proposal described in RFC
7942. The description of implementations in this section is
intended [RFC7580] to assist the IETF in its decision processes carry flexi-grid-
specific information in progressing
drafts to RFCs. Please note that the listing of any individual
implementation here OSPF Opaque LSAs. This document does not imply endorsement by
introduce any further security issues other than those discussed in
[RFC3630] and [RFC4203]. To be more specific, the IETF.
Furthermore, no effort has been spent security
mechanisms described in [RFC2328], which apply to verify Opaque LSAs carried
in OSPF, still apply. An analysis of the information
presented here that was supplied by IETF contributors. This OSPF security is not
intended as, provided
in [RFC6863] and must not be construed applies to be, a catalog of available
implementations or their features. Readers are advised to note that
other implementations may exist.

According to RFC 7942, "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable
experimentation and feedback that have made the implemented
protocols more mature. It is up to the individual working groups to
use this information as they see fit.

6.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)

Organization Responsible for the Implementation: CTTC - Centre
Tecnologic de Telecomunicacions de Catalunya (CTTC), Optical
Networks and Systems Department, http://wikiona.cttc.es.

Implementation Name and Details: ADRENALINE testbed,
http://networks.cttc.es/experimental-testbeds/

Brief Description: Experimental testbed implementation of
GMPLS/PCE control plane.

Level of Maturity: Implemented as extensions to a mature
GMLPS/PCE control plane. It is limited to research / prototyping
stages but it has been used successfully for more than the last five
years.

Coverage: Support for the 64 bit label [RFC7699] for flexi-grid
as described in this document, with available label set encoded as
bitmap.

It is expected that this implementation will evolve to follow the
evolution of this document.

Licensing: Proprietary

Implementation Experience: Implementation of this document
reports no issues. General implementation experience has been
reported in a number of journal papers. Contact Ramon Casellas for
more information or see http://networks.cttc.es/publications/?
search=GMPLS&research_area=optical-networks-systems

Contact Information: Ramon Casellas: ramon.casellas@cttc.es

Interoperability: No report.

7. Acknowledgments

This work was supported in part by the FP-7 IDEALIST project under
grant agreement number 317999.

This work was supported in part by NSFC Project 61201260.

8. Security Considerations

This document extends [RFC4203] and [RFC7580] to carry flex-grid
specific information in OSPF Opaque LSAs. This document does not
introduce any further security issues other than those discussed in
[RFC3630], [RFC4203]. To be more specific, the security mechanisms
described in [RFC2328] which apply to Opaque LSAs carried in OSPF
still apply. An analysis of the OSPF security is provided in
[RFC6863] and applies to the extensions the extensions to OSPF in this document
as well.

9. Contributors' Addresses

Adrian Farrel
Juniper Networks
Email: afarrel@juniper.net

Fatai Zhang
Huawei Technologies
Email: zhangfatai@huawei.com

Lei Wang,
Beijing University of Posts and Telecommunications
Email: wang.lei@bupt.edu.cn

Guoying Zhang,
China Academy of Information and Communication Technology
Email: zhangguoying@ritt.cn

10.

7. References

10.1.

7.1. Normative References

[G.694.1] International Telecommunication Union, "Spectral grids for
WDM applications: DWDM frequency grid", ITU-T
Recommendation G.694.1, February 2012,
<https://www.itu.int/rec/T-REC-G.694.1/en>.

[RFC2119] S. Bradner, S., "Key words for use in RFCs to indicate
requirements levels", Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997.

[G.694.1] ITU-T Recommendation G.694.1 (revision 2), "Spectral grids
for WDM applications: DWDM frequency grid", February 2012. 1997,
<https://www.rfc-editor.org/info/rfc2119>.

[RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description",
RFC 3471, DOI 10.17487/RFC3471, January 2003,
<https://www.rfc-editor.org/info/rfc3471>.

[RFC4203] K. Kompella, K., Ed. and Y. Rekhter, " OSPF Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005. 2005,
<https://www.rfc-editor.org/info/rfc4203>.

[RFC6205] Otani, T., Ed. and D. Li, Ed., "Generalized Labels for
Lambda-Switch-Capable (LSC) Label Switching Routers",
RFC 6205, DOI 10.17487/RFC6205, March 2011,
<https://www.rfc-editor.org/info/rfc6205>.

[RFC7579] Bernstein, G., Ed., Lee, Y., Ed., Li, D., and W. Imajuku, W., and
J. Han, "General Network Element Constraint Encoding for GMPLS Controlled
GMPLS-Controlled Networks", RFC 7579,
DOI 10.17487/RFC7579, June 2015. 2015,
<https://www.rfc-editor.org/info/rfc7579>.

[RFC7580] F. Zhang, Y. F., Lee, J. Y., Han, G. Bernstein J., Bernstein, G., and Y. Xu,
"OSPF-TE Extensions for General Network Element Constraints ",
Constraints", RFC 7580, DOI 10.17487/RFC7580, June 2015.

[RFC6205] T. Otani and D. 2015,
<https://www.rfc-editor.org/info/rfc7580>.

[RFC7699] Farrel, A., King, D., Li, Y., and F. Zhang, "Generalized
Labels for Lambda-Switch- the Flexi-Grid in Lambda Switch Capable (LSC)
Label Switching Routers", RFC 6205, March
2011.

[RFC7699] King, 7699, DOI 10.17487/RFC7699,
November 2015, <https://www.rfc-editor.org/info/rfc7699>.

[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.

[RFC8258] Ceccarelli, D. and L. Berger, "Generalized SCSI: A Generic
Structure for Interface Switching Capability Descriptor
(ISCD) Switching Capability Specific Information (SCSI)",
RFC 8258, DOI 10.17487/RFC8258, October 2017,
<https://www.rfc-editor.org/info/rfc8258>.

7.2. Informative References

[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.

[RFC3630] Katz, D., Farrel, A. Kompella, K., and Y. Li, "Generalized Labels for
the Flexi-Grid in Lambda Switch Capable (LSC) Label
Switching Routers", RFC7699, D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2015.

10.2. Informative References 2003,
<https://www.rfc-editor.org/info/rfc3630>.

[RFC6163] Y. Lee, G. Bernstein Y., Ed., Bernstein, G., Ed., and W. Imajuku,
"Framework for GMPLS and Path Computation Element (PCE)
Control of Wavelength Switched Optical Networks (WSONs)",
RFC 6163, DOI 10.17487/RFC6163, April 2011.

[RFC7792] F.Zhang et al, "RSVP-TE Signaling Extensions in support 2011,
<https://www.rfc-editor.org/info/rfc6163>.

[RFC6863] Hartman, S. and D. Zhang, "Analysis of
Flexible-grid", OSPF Security
According to the Keying and Authentication for Routing
Protocols (KARP) Design Guide", RFC 7792, 6863,
DOI 10.17487/RFC6863, March 2013,
<https://www.rfc-editor.org/info/rfc6863>.

[RFC7688] Lee, Y., Ed. and G. Bernstein, Ed., "GMPLS OSPF
Enhancement for Signal and Network Element Compatibility
for Wavelength Switched Optical Networks", RFC 7688,
DOI 10.17487/RFC7688, November 2015. 2015,
<https://www.rfc-editor.org/info/rfc7688>.

[RFC7698] Gonzalez de Dios, O., Casellas Ed., Casellas, R., Ed., Zhang, F.,
Fu, X., Ceccarelli, D., and I. Hussain, "Framework and
Requirements for GMPLS based control GMPLS-Based Control of Flexi-grid DWDM
networks', Flexi-Grid Dense
Wavelength Division Multiplexing (DWDM) Networks",
RFC 7698, August 2015.

[RFC7688] Y. Lee and G. Bernstein, "GMPLS OSPF Enhancement for
Signal DOI 10.17487/RFC7698, November 2015,
<https://www.rfc-editor.org/info/rfc7698>.

[RFC7792] Zhang, F., Zhang, X., Farrel, A., Gonzalez de Dios, O.,
and Network Element Compatibility for Wavelength
Switched Optical Networks ", RFC7688, August 2015.

[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

[RFC3630] D. Katz, K. Kompella, D. Yeung, " Traffic Engineering
(TE) Ceccarelli, "RSVP-TE Signaling Extensions to OSPF Version 2", September 2003.

[RFC6863] Hartman, S. and D. Zhang, "Analysis in
Support of OSPF Security
According to the Keying and Authentication for Routing
Protocols (KARP) Design Guide", Flexi-Grid Dense Wavelength Division
Multiplexing (DWDM) Networks", RFC 6863, 7792,
DOI 10.17487/RFC7792, March 2013. 2016,
<https://www.rfc-editor.org/info/rfc7792>.

Acknowledgments

This work was supported in part by the FP-7 IDEALIST project under
grant agreement number 317999.

This work was supported in part by NSFC Project 61201260.

Contributors

Adrian Farrel
Juniper Networks

Email: afarrel@juniper.net

Fatai Zhang
Huawei Technologies

Email: zhangfatai@huawei.com

Lei Wang
Beijing University of Posts and Telecommunications

Email: wang.lei@bupt.edu.cn

Guoying Zhang
China Academy of Information and Communication Technology

Email: zhangguoying@ritt.cn

Authors' Addresses

Xian Zhang
Huawei Technologies

Email: zhang.xian@huawei.com

Haomian Zheng
Huawei Technologies

Email: zhenghaomian@huawei.com

Ramon Casellas, Ph.D.
CTTC
Spain

Phone: +34 936452916
Email: ramon.casellas@cttc.es

Oscar Gonzalez de Dios
Telefonica Investigacion y Desarrollo
Emilio Vargas 6
Madrid, 28045
Spain

Phone: +34 913374013
Email: ogondio@tid.es oscar.gonzalezdedios@telefonica.com

Daniele Ceccarelli
Ericsson
Via A. Negrone 1/A
Genova - Sestri Ponente
Italy

Email: daniele.ceccarelli@ericsson.com