draft-ietf-ccamp-grid-property-lmp-00.txt   draft-ietf-ccamp-grid-property-lmp-01.txt 
Network Working Group CCAMP
Internet Draft Y.Li
Intended status: Informational ZTE
Expires: December 2014 G.Zhang
CATR
X.Fu
ZTE
R. Casellas
CTTC
Y.Wang
CATR
June 20, 2014
Link Management Protocol Extensions for Grid Property Negotiation Network Working Group X. Fu, Ed.
draft-ietf-ccamp-grid-property-lmp-00.txt Internet-Draft ZTE
Intended status: Standards Track G. Zhang, Ed.
Expires: September 10, 2015 CAICT
Y. Li
Nanjing University
R. Casellas
CTTC
Y. Wang
CAICT
March 9, 2015
Status of this Memo Link Management Protocol Extensions for Grid Property Negotiation
draft-ietf-ccamp-grid-property-lmp-01
Abstract
ITU-T [G.694.1] introduces the flexible-grid DWDM technique, which
provides a new tool that operators can implement to provide a higher
degree of network optimization than is possible with fixed-grid
systems. This document describes the extensions to the Link
Management Protocol (LMP) to negotiate link grid property between the
adjacent DWDM nodes before the link is brought up.
Status of This Memo
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Abstract
The recent updated version of ITU-T [G.694.1] has introduced the
flexible-grid DWDM technique, which provides a new tool that operators
can implement to provide a higher degree of network optimization than
is possible with fixed-grid systems. This document describes the
extensions to the Link Management Protocol (LMP) to negotiate link grid
property between the adjacent DWDM nodes before the link is brought up.
Table of Contents Table of Contents
1. Introduction...................................................3
1.1. Conventions Used in This Document.........................3
2. Terminology....................................................3
3. Requirements for Grid Property Negotiation.....................4
3.1. Flexi-fixed Grid Nodes Interworking.......................4
3.2. Flexible-Grid Capability Negotiation......................5
3.3. Summary...................................................5
4. LMP extensions.................................................6
4.1. Grid Property Subobject...................................6
5. Messages Exchange Procedure....................................8
5.1. Flexi-fixed Grid Nodes Messages Exchange..................8
5.2. Flexible Nodes Messages Exchange..........................9
6. Security Considerations.......................................10
7. IANA Considerations...........................................10
8. References....................................................10
8.1. Normative references.....................................10
8.2. Informative References...................................11
9. Authors' Address..............................................11
10. Contributors' Address........................................12
1. Introduction 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions Used in This Document . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirements for Grid Property Negotiation . . . . . . . . . 3
3.1. Flexi-fixed Grid Nodes Interworking . . . . . . . . . . . 3
3.2. Flexible-Grid Capability Negotiation . . . . . . . . . . 4
3.3. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. LMP extensions . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Grid Property Subobject . . . . . . . . . . . . . . . . . 5
5. Messages Exchange Procedure . . . . . . . . . . . . . . . . . 7
5.1. Flexi-fixed Grid Nodes Messages Exchange . . . . . . . . 7
5.2. Flexible Nodes Messages Exchange . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 9
9. Contributing Authors . . . . . . . . . . . . . . . . . . . . 9
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
10.1. Normative References . . . . . . . . . . . . . . . . . . 10
10.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
The recent updated version of ITU-T [G.694.1] has introduced the 1. Introduction
flexible-grid DWDM technique, which provides a new tool that
operators can implement to provide a higher degree of network ITU-T [G.694.1] introduces the flexible-grid DWDM technique, which
optimization than is possible with fixed-grid systems. A flexible- provides a new tool that operators can implement to provide a higher
grid network supports allocating a variable-sized spectral slot to a degree of network optimization than is possible with fixed-grid
channel. Flexible-grid DWDM transmission systems can allocate their systems. A flexible-grid network supports allocating a variable-
channels with different spectral bandwidths/slot widths so that they sized spectral slot to a channel. Flexible-grid DWDM transmission
can be optimized for the bandwidth requirements of the particular systems can allocate their channels with different spectral
bit rate and modulation scheme of the individual channels. This bandwidths/slot widths so that they can be optimized for the
technique is regarded to be a promising way to improve the spectrum bandwidth requirements of the particular bit rate and modulation
utilization efficiency and can be used in the beyond 100Gb/s scheme of the individual channels. This technique is regarded to be
transport systems. a promising way to improve the spectrum utilization efficiency and
can be used in the beyond 100Gbit/s transport systems.
Fixed-grid DWDM system is regarded as a special case of Flexi-grid Fixed-grid DWDM system is regarded as a special case of Flexi-grid
DWDM. It is expected that fixed-grid optical nodes will be gradually DWDM. It is expected that fixed-grid optical nodes will be gradually
replaced by flexible nodes and interworking between fixed-grid DWDM replaced by flexible nodes and interworking between fixed-grid DWDM
and flexible-grid DWDM nodes will be needed as the network evolves. and flexible-grid DWDM nodes will be needed as the network evolves.
Additionally, even two flexible-grid optical nodes may have Additionally, even two flexible-grid optical nodes may have different
different grid properties based on the filtering component grid properties based on the filtering component characteristics,
characteristics, thus need to negotiate on the specific parameters thus need to negotiate on the specific parameters to be used during
to be used during neighbor discovery process [draft-ietf-ccamp- neighbor discovery process [FLEX-FWK]. This document describes the
flexi-grid-fwk-00]. This document describes the extensions to the extensions to the Link Management Protocol (LMP) to negotiate a link
Link Management Protocol (LMP) to negotiate a link grid property grid property between two adjacent nodes before the link is brought
between two adjacent Flexi-grid nodes before the link is brought up. up.
1.1. Conventions Used in This Document
1.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Terminology 2. Terminology
For the flexible-grid DWDM, the spectral resource is called For the flexible-grid DWDM, the spectral resource is called frequency
frequency slot which is represented by the central frequency and the slot which is represented by the central frequency and the slot
slot width. The defined nominal central frequency and the slot width width. The definition of nominal central frequency, nominal central
can be referred to [FLEX-FWK]. frequency granularity, slot width and slot width granularity can be
referred to [FLEX-FWK].
In this contribution, some other definitions are listed below: In this contribution, some other definitions are listed below:
Central frequency granularity: It is the granularity of the allowed
central frequencies and is set to the multiple of 6.25 GHz.
Slot width granularity: It is the granularity of the allowed slot
width, and is set to the multiple of 12.5 GHz.
Tuning range: It describes the supported spectrum slot range of the Tuning range: It describes the supported spectrum slot range of the
switching nodes or interfaces. It is represented by the supported switching nodes or interfaces. It is represented by the supported
minimal slot width and the maximum slot width. minimal slot width and the maximum slot width.
Channel spacing: It is used in traditional fixed-grid network to Channel spacing: It is used in traditional fixed-grid network to
identify spectrum spacing between two adjacent channels. identify spectrum spacing between two adjacent channels.
3. Requirements for Grid Property Negotiation 3. Requirements for Grid Property Negotiation
3.1. Flexi-fixed Grid Nodes Interworking 3.1. Flexi-fixed Grid Nodes Interworking
Figure 1 shows an example of interworking between flexible and
fixed-grid nodes. Node A, B, D and E support flexible-grid. All Figure 1 shows an example of interworking between flexible and fixed-
these nodes can support frequency slots with a central frequency grid nodes. Node A, B, D and E support flexible-grid. All these
nodes can support frequency slots with a central frequency
granularity of 6.25 GHz and slot width granularity of 12.5 GHz. granularity of 6.25 GHz and slot width granularity of 12.5 GHz.
Given the flexibility in flexible-grid nodes, it is possible to Given the flexibility in flexible-grid nodes, it is possible to
configure the nodes in such a way that the central frequencies and configure the nodes in such a way that the central frequencies and
slot width parameters are backwards compatible with the fixed DWDM slot width parameters are backwards compatible with the fixed DWDM
grids (adjacent flexible frequency slots with channel spacing of grids (adjacent flexible frequency slots with channel spacing of
8*6.25 and slot width of 4*12.5 GHz is equivalent to fixed DWDM 8*6.25 and slot width of 4*12.5 GHz is equivalent to fixed DWDM grids
grids with channel spacing of 50 GHz). with channel spacing of 50 GHz).
As node C can only support the fixed-grid DWDM property with channel As node C can only support the fixed-grid DWDM property with channel
spacing of 50 GHz, to establish a LSP through node B, C, D, the spacing of 50 GHz, to establish a LSP through node B, C, D, the links
links between B to C and C to D must set to align with the fixed- between B to C and C to D must set to align with the fixed-grid
grid values. This link grid property must be negotiated before values. This link grid property must be negotiated before
establishing the LSP. establishing the LSP.
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
| A |---------| B |=========| C |=========| D +--------+ E | | A |---------| B |=========| C |=========| D +--------+ E |
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
Figure 1 An example of interworking between
flexible and fixed-grid nodes
^ ^ ^ ^ Figure 1: An example of interworking between flexible and fixed-grid
------->|<----50GHz---->|<----50GHz---->|<----50GHz---->|<------ nodes
..... | | | | .....
+-------+-------+-------+-------+-------+--------+------+-------+-
n=-2 -1 0 1 2
Fixed channel spacing of 50 GHz (Node C)
^ ^ ^ ^
| | | |
^ ^ ^ ^
------->|<----50GHz---->|<----50GHz---->|<----50GHz---->|<------
..... | | | | .....
+-------+-------+-------+-------+-------+--------+------+-------+-
n=-2 -1 0 1 2
Fixed channel spacing of 50 GHz (Node C)
^ ^ ^ ^
| | | |
--------+---------------+---------------+---------------+--------- --------+---------------+---------------+---------------+---------
..... | n=-8, m=4 | n=0, m=4 | n=8, m=4 | ..... ..... | n=-8, m=4 | n=0, m=4 | n=8, m=4 | .....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
n=-16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 n=-16 -14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16
|_| |_|
Flexi-grid (Nodes B,D) 6.25 GHz Flexi-grid (Nodes B,D) 6.25 GHz
Central frequency granularity=6.25 GHz Central frequency granularity=6.25 GHz
Slot width granularity=12.5 GHz Slot width granularity=12.5 GHz
Figure 2 Representation of fixed channel spacing
and flexi-grid spectrum slot
3.2. Flexible-Grid Capability Negotiation Figure 2: Representation of fixed channel spacing and flexi-grid
spectrum slot
3.2. Flexible-Grid Capability Negotiation
The updated version of ITU-T [G.694.1] has defined the flexible-grid The updated version of ITU-T [G.694.1] has defined the flexible-grid
with a central frequency granularity of 6.25 GHz and a slot width with a central frequency granularity of 6.25 GHz and a slot width
granularity of 12.5 GHz. However, devices or applications that make granularity of 12.5 GHz. However, devices or applications that make
use of the flexible-grid may not be able to support every possible use of the flexible-grid may not be able to support every possible
slot width. In other words, applications may be defined where slot width or position. In other words, applications may be defined
different grid granularity can be supported. Taking node G as an where only a subset of the possible slot widths and positions are
example, an application could be defined where the central frequency required to be supported. Taking node G in figure 3 as an example,
granularity is 12.5 GHz requiring slot widths being multiple of 25 an application could be defined where the nominal central frequency
GHz. Therefore the link between two optical nodes with different granularity is 12.5 GHz (by only requiring values of n that are even)
grid granularity must be configured to align with the larger of both requiring slot widths being multiple of 25 GHz (by only requiring
granularities. Besides, different nodes may have different slot values of m that are even). Therefore the link between two optical
width tuning ranges. For example, in figure 3, node F can only node F and G with different grid granularity must be configured to
support slot width with tuning change from 12.5 to 100 GHz, while align with the larger of both granularities. Besides, different
node G supports tuning range from 25 GHz to 200 GHz. The link nodes may have different slot width tuning ranges. For example, in
property of slot width tuning range for the link between F and G figure 3, node F can only support slot width with tuning change from
should be chosen as the range intersection, resulting in a range 12.5 to 100 GHz, while node G supports tuning range from 25 GHz to
from 25 GHz to 100 GHz. 200 GHz. The link property of slot width tuning range for the link
+---+ +---+ between F and G should be chosen as the range intersection, resulting
| F +------------| G | in a range from 25 GHz to 100 GHz.
+---+ +---+
+---+ +---+
| F +------------| G |
+---+ +---+
+------------------+-------------+-----------+ +------------------+-------------+-----------+
| Unit (GHz) | Node F | Node G | | Unit (GHz) | Node F | Node G |
+------------------+-------------+-----------+ +------------------+-------------+-----------+
| Grid granularity | 6.25 (12.5) | 12.5 (25) | | Grid granularity | 6.25 (12.5) | 12.5 (25) |
+------------------+-------------+-----------+ +------------------+-------------+-----------+
| Tuning range | [12.5, 100] | [25, 200] | | Tuning range | [12.5, 100] | [25, 200] |
+------------------+-------------+-----------+ +------------------+-------------+-----------+
Figure 3 An example of flexible-grid capability negotiation
3.3. Summary Figure 3: An example of flexible-grid capability negotiation
3.3. Summary
In summary, in a DWDM Link between two nodes, the following In summary, in a DWDM Link between two nodes, the following
properties can be negotiated: properties should be negotiated:
o Grid capability: flexible grid or fixed grid DWDM. o Grid capability: flexible grid or fixed grid DWDM.
o Central frequency granularity: a multiplier of 6.25 GHz. o Nominal central frequency granularity: a multiplier of 6.25 GHz.
o Slot width granularity: a multiplier of 12.5 GHz. o Slot width granularity: a multiplier of 12.5 GHz.
o Slot width tuning range: two multipliers of 12.5GHz, each o Slot width tuning range: two multipliers of 12.5GHz, each indicate
indicate the minimal and maximal slot width supported by a port the minimal and maximal slot width supported by a port respectively.
respectively.
4. LMP extensions 4. LMP extensions
4.1. Grid Property Subobject
According to [RFC4204], the LinkSummary message is used to verify 4.1. Grid Property Subobject
the consistency of the link property on both sides of the link
before it is brought up. The LinkSummary message contains negotiable According to [RFC4204], the LinkSummary message is used to verify the
and non-negotiable DATA_LINK objects, carrying a series of variable- consistency of the link property on both sides of the link before it
length data items called subobjects, which illustrate the detailed is brought up. The LinkSummary message contains negotiable and non-
link properties. The subobjects are defined in Section 12.12.1 in negotiable DATA_LINK objects, carrying a series of variable-length
data items called subobjects, which illustrate the detailed link
properties. The subobjects are defined in Section 12.12.1 in
[RFC4204]. [RFC4204].
To solve the problems stated in section 3, this draft extends the
To meet the requirements stated in section 3, this draft extends the
LMP protocol by introducing a new DATA_LINK subobject called "Grid LMP protocol by introducing a new DATA_LINK subobject called "Grid
property", allowing the grid property correlation between adjacent property", allowing the grid property correlation between adjacent
nodes. The encoding format of this new subobject is as follows: nodes. The encoding format of this new subobject is as follows:
0 1 2 3 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 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Reserved | | Type | Length | Grid | C.F.G | S.W.G |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Grid | C.F.G | S.W.G | Min | Max | | Min Width | Reserved | Max Width |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4
Type=TBD, Grid property type. Type=TBD, Grid property type.
Grid: Grid: 4 bits
The value is used to represent which grid the node/interface The value is used to represent which grid the node/interface
supports. Values defined in [RFC6205] identify DWDM [G.694.1] and supports. Values defined in [RFC6205] identify DWDM [G.694.1] and
CWDM [G.694.2]. The value defined in [I-D.farrkingel-ccamp- CWDM [G.694.2]. The value defined in [draft-ietf-ccamp-flexigrid-
flexigrid-lambda-label] identifies flexible DWDM. lambda-label] identifies flexible DWDM.
+---------------+-------+
| Grid | Value | +---------------+-------+
+---------------+-------+ | Grid | Value |
| Reserved | 0 | +---------------+-------+
+---------------+-------+ | Reserved | 0 |
| ITU-T DWDM | 1 | +---------------+-------+
+---------------+-------+ | ITU-T DWDM | 1 |
| ITU-T CWDM | 2 | +---------------+-------+
+---------------+-------+ | ITU-T CWDM | 2 |
| Flexible DWDM | 3 | +---------------+-------+
+---------------+-------+ | ITU-T Flex | 3 |
| Future use | 4-16 | +---------------+-------+
+---------------+-------+ | Future use | 4-16 |
+---------------+-------+
C.F.G (central frequency granularity): C.F.G (central frequency granularity):
For a fixed-grid node/interface, the C.F.G value is used to It is a positive integer. Its value indicates the multiple of 6.25
represent the channel spacing, as the spacing between adjacent GHz in terms of central frequency granularity.
channels is constant. For a flexible-grid node/interface, this field
should be used to represent the central frequency granularity which
is the multiple of 6.25 GHz.
+------------+-------+
| C.F.G (GHz) | Value |
+------------+-------+
| Reserved | 0 |
+------------+-------+
| 100 | 1 |
+------------+-------+
| 50 | 2 |
+------------+-------+
| 25 | 3 |
+------------+-------+
| 12.5 | 4 |
+------------+-------+
| 6.25 | 5 |
+------------+-------+
| Future use | 6-15 |
+------------+-------+
S.W.G (Slot Width Granularity): S.W.G (Slot Width Granularity):
It is a positive integer value which indicates the slot width It is a positive integer value which indicates the slot width
granularity which is the multiple of 12.5 GHz. granularity which is the multiple of 12.5 GHz.
Min & Max: Min Width and Max Width:
Min & Max indicate the slot width tuning range the interface Min Width and Max Width are positive integers. Their value indicate
supports (as defined in section 2). For example, for slot width the multiple of 12.5 GHz in terms of the slot width tuning range the
tuning range from 25 GHz to 100 GHz (with regard to a node with slot interface supports. For example, for slot width tuning range from 25
width granularity of 12.5 GHz), the values of Min and Max should be GHz to 100 GHz (with regard to a node with slot width granularity of
2 and 8 respectively. For fixed-grid nodes, these two fields are 12.5 GHz), the values of Min Width and Max Width should be 2 and 8
meaningless and should be set to zero. respectively. For fixed-grid nodes, these two fields are meaningless
and should be set to zero.
5. Messages Exchange Procedure 5. Messages Exchange Procedure
5.1. Flexi-fixed Grid Nodes Messages Exchange
5.1. Flexi-fixed Grid Nodes Messages Exchange
To demonstrate the procedure of grid property correlation, the model To demonstrate the procedure of grid property correlation, the model
shown in Figure 1 is reused. Node B starts sending messages. shown in Figure 1 is reused. Node B starts sending messages.
o After inspecting its own node/interface property, node B sends o After inspecting its own node/interface property, node B sends node
node C a LinkSummary message including the MESSAGE ID, TE_LINK ID C a LinkSummary message including the MESSAGE ID, TE_LINK ID and
and DATA_LINK objects. The setting and negotiating of MESSAGE ID DATA_LINK objects. The setting and negotiating of MESSAGE ID and
and TE_link ID can be referenced to [RFC4204]. As node B TE_link ID can be referenced to [RFC4204]. As node B supports
supports flexible-grid property, the Grid and C.S. values in the flexible-grid property, the Grid and C.F.G values in the grid
grid property subobject are set to be 3 and 5 respectively. The property subobject are set to be 3 (i.e., ITU-T Flex) and 1
slot width tuning range is from 12.5 GHz to 200 GHz. Meanwhile, (i.e.,1*6.25GHz) respectively. The slot width tuning range is from
the N bit of the DATA_LINK object is set to 1, indicating that 12.5 GHz to 200 GHz (i.e., Min Width=1, Max Width=16). Meanwhile,
the property is negotiable. the N bit of the DATA_LINK object is set to 1, indicating that the
o When node C receives the LinkSummary message from B, it checks property is negotiable.
the Grid, C.S., Min and Max values in the grid property subobject.
Node C can only support fixed-grid DWDM and realizes that the
flexible-grid property is not acceptable for the link. Since the
receiving N bit in the DATA_LINK object is set, indicating that
the Grid property of B is negotiable, node C responds to B with a
LinkSummaryNack containing a new Error_code object and state that
the property needs further negotiation. Meanwhile, an accepted
grid property subobject (Grid=2, C.S.=2, fixed DWDM with channel
spacing of 50 GHz) is carried in LinkSummaryNack message. At
this moment, the N bit in the DATA_LINK object is set to 0,
indicating that the grid property subobject is non-negotiable.
o As the channel spacing and slot width of node B can be configured o When node C receives the LinkSummary message from B, it checks the
to be any integral multiples of 6.25 GHz and 12.5 GHz Grid, C.F.G, Min and Max values in the grid property subobject. Node
respectively, node B supports the fixed DWDM values announced by C can only support fixed-grid DWDM and realizes that the flexible-
node C. Consequently, node B will resend the LinkSummary message grid property is not acceptable for the link. Since the receiving N
carrying the grid property subobject with values of Grid=2 and bit in the DATA_LINK object is set, indicating that the Grid property
C.S.=2. of B is negotiable, node C responds to B with a LinkSummaryNack
containing a new Error_code object and state that the property needs
further negotiation. Meanwhile, an accepted grid property subobject
(Grid=2, C.F.G=4, fixed DWDM with channel spacing of 50 GHz) is
carried in LinkSummaryNack message. At this moment, the N bit in the
DATA_LINK object is set to 0, indicating that the grid property
subobject is non-negotiable.
o Once received the LinkSummary message from node B, node C replies o As the channel spacing and slot width of node B can be configured
with a LinkSummaryACK message. After the message exchange, the to be any integral multiples of 6.25 GHz and 12.5 GHz respectively,
link between node B and C is brought up with a fixed channel node B supports the fixed DWDM values announced by node C.
spacing of 50 GHz. Consequently, node B will resend the LinkSummary message carrying the
grid property subobject with values of Grid=2 and C.F.G=4.
o Once received the LinkSummary message from node B, node C replies
with a LinkSummaryACK message. After the message exchange, the link
between node B and C is brought up with a fixed channel spacing of 50
GHz.
In the above mentioned grid property correlation scenario, the node In the above mentioned grid property correlation scenario, the node
supporting a flexible-grid is the one that starts sending LMP supporting a flexible-grid is the one that starts sending LMP
messages. The procedure where the initiator is the fixed-grid node messages. The procedure where the initiator is the fixed-grid node
is as follows: is as follows:
o After inspecting its own interface property, Node C sends B a o After inspecting its own interface property, Node C sends B a
LinkSummary message containing a grid property subobject with LinkSummary message containing a grid property subobject with Grid=2,
Grid=2, C.S.=2. The N bit in the DATA_LINK object is set to 0, C.F.G=4. The N bit in the DATA_LINK object is set to 0, indicating
indicating that it is non-negotiable. that it is non-negotiable.
o As the channel spacing and slot width of node B can be configured o As the channel spacing and slot width of node B can be configured
to be any integral multiples of 6.25 GHz and 12.5 GHz to be any integral multiples of 6.25 GHz and 12.5 GHz respectively,
respectively, node B is able to support the fixed DWDM parameters. node B is able to support the fixed DWDM parameters. Then, node B
Then, node B will make appropriate configuration and reply node C will make appropriate configuration and reply node C the
the LinkSummaryACK message. LinkSummaryACK message
o After the message exchange, the link between node B and C is o After the message exchange, the link between node B and C is
brought up with a fixed channel spacing of 50 GHz. brought up with a fixed channel spacing of 50 GHz.
5.2. Flexible Nodes Messages Exchange 5.2. Flexible Nodes Messages Exchange
To demonstrate the procedure of grid property correlation between to To demonstrate the procedure of grid property correlation between to
flexi-grid capable nodes, the model shown in figure 3 is reused. The flexi-grid capable nodes, the model shown in figure 3 is reused. The
procedure of grid property correlation (negotiating the grid procedure of grid property correlation (negotiating the grid
granularity and slot width tuning range) is similar to the scenarios granularity and slot width tuning range) is similar to the scenarios
mentioned above. mentioned above.
o The Grid, C.S., Min and Max values in the grid property subobject
sent from node F to G are set to be 3,5,1,8 respectively.
Meanwhile, the N bit of the DATA_LINK object is set to 1,
indicating that the grid property is negotiable.
o When node G has received the LinkSummary message from F, it will o The Grid, C.F.G, Min and Max values in the grid property subobject
analyze the Grid, C.S., Min and Max values in the Grid property sent from node F to G are set to be 3,1,1,8 respectively. Meanwhile,
subobject. But node G can only support grid granularity of 12.5 the N bit of the DATA_LINK object is set to 1, indicating that the
GHz and a slotwdith tuning range from 25 GHz to 200 GHz. grid property is negotiable.
Considering the property of node F, node G then will respond F a
LinkSummaryNack containing a new Error_code object and state that o When node G has received the LinkSummary message from F, it will
the property need further negotiation. Meanwhile, an accepted analyze the Grid, C.F.G, Min and Max values in the Grid property
grid property subobject (Grid=3, C.S.=4, Min=1, Max=4, the slot subobject. But node G can only support grid granularity of 12.5 GHz
width tuning range is set to the intersection of Node F and G) is and a slotwdith tuning range from 25 GHz to 200 GHz. Considering the
carried in LinkSummaryNack message. Meanwhile, the N bit in the property of node F, node G then will respond F a LinkSummaryNack
DATA_LINK object is set to 1, indicating that the grid property containing a new Error_code object and state that the property need
subobject is non-negotiable. further negotiation. Meanwhile, an accepted grid property subobject
(Grid=3, C.F.G=2, Min=2, Max=8, the slot width tuning range is set to
the intersection of Node F and G) is carried in LinkSummaryNack
message. Meanwhile, the N bit in the DATA_LINK object is set to 1,
indicating that the grid property subobject is non-negotiable.
o As the channel spacing and slot width of node F can be configured o As the channel spacing and slot width of node F can be configured
to be any integral multiples of 6.25 GHz and 12.5 GHz to be any integral multiples of 6.25 GHz and 12.5 GHz respectively,
respectively, node F can support the lager granularity. The node F can support the lager granularity. The suggested slot width
suggested slot width tuning range is acceptable for node F. In tuning range is acceptable for node F. In consequence, node F will
consequence, node F will resend the LinkSummary message carrying resend the LinkSummary message carrying the grid subobject with
the grid subobject with values of Grid=3, C.S.=4, Min=1 and Max=4. values of Grid=3, C.F.G=2, Min=2 and Max=8.
o Once received the LinkSummary message from node F, node G replies o Once received the LinkSummary message from node F, node G replies
with a LinkSummaryACK message. After the message exchange, the with a LinkSummaryACK message. After the message exchange, the link
link between node F and G is brought up supporting central between node F and G is brought up supporting central frequency
frequency granularity of 12.5 GHz and slot width tuning range granularity of 12.5 GHz and slot width tuning range from 25 GHz to
from 25 GHz to 100 GHz. 100 GHz.
From the perspective of the control plane, once the links have been From the perspective of the control plane, once the links have been
brought up, wavelength constraint information can be advertised and brought up, wavelength constraint information can be advertised and
the wavelength label can be assigned hop-by-hop when establishing a the wavelength label can be assigned hop-by-hop when establishing a
LSP based on the link grid property. LSP based on the link grid property.
6. Security Considerations 6. IANA Considerations
TBD. This draft introduces the following new assignments:
7. IANA Considerations
TBD. LMP Sub-Object Class names:
8. References
8.1. Normative references
[G.694.1] International Telecommunications Union, "Spectral grids o under DATA_LINK Class name (as defined in [RFC4204])
for WDM applications: DWDM frequency grid", Recommendation
G.694.1, June 2002.
[G.694.2] International Telecommunications Union, "Spectral grids
for WDM applications: CWDM wavelength grid",
Recommendation G.694.2, December 2003.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate - Grid property type (sub-object Type = TBD.)
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4204] Lang, J., "Link Management Protocol (LMP)", RFC 4204, 7. Acknowledgments
October 2005.
[RFC6205] Otani, T. and D. Li, "Generalized Labels for Lambda- This work was supported in part by the China NSFC Project 61201260.
Switch-Capable (LSC) Label Switching Routers", RFC 6205,
March 2011.
8.2. Informative References 8. Security Considerations
[I-D.farrkingel-ccamp-flexigrid-lambda-label] LMP message security uses IPsec, as described in [RFC4204]. This
Farrel, A., King, D., Li, Y., Zhang, F., document only defines new LMP objects that are carried in existing
"Generalized Labels for the Flexi-Grid in Lambda-Switch- LMP messages. As such, this document introduces no other new
Capable (LSC) Label Switching Routers", draft-farrkingel- security considerations not covered in [RFC4204].
ccamp-flexigrid-lambda-label-08 (work in progress),
February 2014.
[FLEX-FWK] 9. Contributing Authors
Dios, O., Casellas, R., Zhang, F., Fu, X., Ceccarelli, D.,
and I. Hussain, "Framework for GMPLS based control of
Flexi-grid DWDM networks", draft-ietf-ccamp-flexi-grid-
fwk-00 (work in progress), October 2013.
9. Authors' Address Wenjuan He
Yao Li (editor) ZTE
he.wenjuan1@zte.com.cn
ZTE 10. References
Email: li.yao3@zte.com.cn
Guoying Zhang (editor) 10.1. Normative References
China Academy of Telecom Research, MIIT
Email: zhangguoying@catr.cn [G.694.1] International Telecomunications Union, "Spectral grids for
WDM applications: DWDM frequency grid", Recommendation
G.694.1 , June 2002.
Xihua Fu (editor) [G.694.2] International Telecomunications Union, "Spectral grids for
WDM applications: CWDM wavelength grid", Recommendation
G.694.2 , December 2003.
ZTE [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
Email: fu.xihua@zte.com.cn [RFC4204] Lang, J., "Link Management Protocol (LMP)", RFC 4204,
October 2005.
Ramon Casellas [RFC6205] Otani, T. and D. Li, "Generalized Labels for Lambda-
Switch-Capable (LSC) Label Switching Routers", RFC 6205,
March 2011.
CTTC 10.2. Informative References
Email: ramon.casellas@cttc.es [FLEX-FWK]
Dios, O., Casellas, R., Zhang, F., Fu, X., Ceccarelli, D.,
and I. Hussain, , "Framework for GMPLS based control of
Flexi-grid DWDM networks", draft-ietf-ccamp-flexi-grid-
fwk-02 , August 2014.
Yu Wang [draft-ietf-ccamp-flexigrid-lambda-label]
Farrel, A., King, D., Li, Y., Zhang, F., , "Generalized
Labels for the Flexi-Grid in Lambda-Switch-Capable (LSC)
Label Switching Routers", draft-ietf-ccamp-flexigrid-
lambda-label-03 , January 2015.
China Academy of Telecom Research, MIIT Authors' Addresses
Email: wangyu@catr.cn
10. Contributors' Address Xihua Fu (editor)
ZTE
Wenjuan He (editor) Email: fu.xihua@zte.com.cn
ZTE
Email: he.wenjuan1@zte.com.cn Guoying Zhang (editor)
CAICT
Email: zhangguoying@catr.cn
Yao Li
Nanjing University
Email: wsliguotou@hotmail.com
Ramon Casellas
CTTC
Email: ramon.casellas@cttc.es
Yu Wang
CAICT
Email: wangyu@catr.cn
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