Internet Engineering Task Force Q. Wang, Ed.
Internet-Draft ZTE Corporation
Intended status: Informational R. Valiveti, Ed.
Expires: September 7, 2020 Infinera Corp
H. Zheng, Ed.
Huawei
H. Helvoort
Hai Gaoming B.V
S. Belotti
Nokia
March 6, 2020
Applicability of GMPLS for B100G Optical Transport Network
draft-ietf-ccamp-gmpls-otn-b100g-applicability-02
Abstract
This document examines the applicability of using current existing
GMPLS routing and signaling to set up ODUk/ODUflex over ODUCn link,
as a result of the introduction of OTU/ODU links with rates larger
than 100G in the 2016 version of G.709.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. OTN terminology used in this document . . . . . . . . . . . . 3
3. Overview of B100G in G.709 . . . . . . . . . . . . . . . . . 4
3.1. OTUCn . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. ODUCn . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.3. OTUCn-M . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.4. Time Slot Granularity . . . . . . . . . . . . . . . . . . 8
3.5. Structure of OPUCn MSI with Payload type 0x22 . . . . . . 8
3.6. Client Signal Mappings . . . . . . . . . . . . . . . . . 8
4. Applicability and GMPLS Implications . . . . . . . . . . . . 10
4.1. Applicability and Challenges . . . . . . . . . . . . . . 10
4.2. GMPLS Implications and Applicability . . . . . . . . . . 12
4.2.1. TE-Link Representation . . . . . . . . . . . . . . . 12
4.2.2. Implications and Applicability for GMPLS Signalling . 13
4.2.3. Implications and Applicability for GMPLS Routing . . 14
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
6. Authors (Full List) . . . . . . . . . . . . . . . . . . . . . 15
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 16
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
9. Security Considerations . . . . . . . . . . . . . . . . . . . 17
10. Normative References . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
1. Introduction
The current GMPLS routing [RFC7138] and signaling extensions
[RFC7139] only supports the control of OTN signals and capabilities
that were defined in the 2012 version of G.709 [ITU-T_G709_2012].
Since the publishment of the latest 2016 version of G.709
[ITU-T_G709_2016], which introduces support for new higher rate ODU
signals, termed ODUCn (which have a nominal rate of n x 100 Gbps),
how to applied GMPLS to ODUCn case should be taken into
consideration. As OTUCn and ODUCn only perform section layer role
only according to the definition in G.709 [ITU-T_G709_2016], which
means the OTUCn and ODUCn are only used to provide for the transfer
of information between two adjacent upper layer cross-connects, i.e.,
ODUk/ODUflex cross connects, it's not appropriate to apply GMPLS to
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OTUCn and ODUCn. Therefore, this document mainly focuses on the use
of GMPLS mechanisms to set up ODUk/ODUflex over an existing ODUCn
link.
This document first presents an overview of the changes introduced in
[ITU-T_G709_2016] to motivate the present topic and then analyzes how
the current GMPLS routing and signalling mechanisms can be utilized
to setup ODUk/ODUflex connections over ODUCn links. In order to make
the description in this document clear, how to set up ODUCn link is
also mentioned.
1.1. Scope
For the purposes of the B100G control plane discussion, the OTN
should be considered as a combination of ODU and OTSi layers. Note
that [ITU-T_G709_2016] is deprecating the use of the term "OCh" for
B100G entities, and leaving it intact only for maintaining continuity
in the description of the signals with bandwidth upto 100G.
This document only focuses on the control of the ODU layer. The
control of the OTSi layer is out of scope of this document. But in
order to facilitate the description of the challenges brought by
[ITU-T_G709_2016] to B100G GMPLS routing and signalling, some general
description about OTSi is included in section 4 of this document.
2. OTN terminology used in this document
a. OPUCn: Optical Payload Unit -Cn.
b. ODUCn: Optical Data Unit - Cn.
c. OTUCn: Fully standardized Optical Transport Unit - Cn.
d. OTUCn-M: This signal is an extension of the OTUCn signal
introduced above. This signal contains the same amount of
overhead as the OTUCn signal, but contains a reduced amount of
payload area. Specifically the payload area consists of M 5G
tributary slots (where M is strictly less than 20*n).
e. PSI: OPU Payload structure Indicator. This is a multi-frame
message and describes the composition of the OPU signal. This
field is a concatenation of the Payload type (PT) and the
Multiplex Structrure Indicator (MSI) defined below.
f. MSI: Multiplex Structure Indicator. This structure indicates the
grouping of the tributary slots in an OPU payload area to realize
a client signal that is multiplexed into an OPU. The individual
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clients multiplexed into the OPU payload area are distinguished
by the Tributary Port number (TPN).
g. GMP: Generic Mapping Procedure.
h. OTSiG: The set of OTSi that supports a single digital client.
i. OTSiA: The OTSiG together with the non-associated overhead
(OTSiG-O).
Detailed description of these terms can be found in [ITU-T_G709_2016]
and [ITU-T_G807].
3. Overview of B100G in G.709
This section provides an overview of new features in
[ITU-T_G709_2016].
3.1. OTUCn
In order to carry client signals with rates greater than 100Gbps,
[ITU-T_G709_2016] takes a general and scalable approach that
decouples the rates of OTU signals from the client rate. The new OTU
signal is called OTUCn, and this signal is defined to have a rate of
(approximately) n*100G. The following are the key characteristics of
the OTUCn signal:
a. The OTUCn signal contains one ODUCn. The OTUCn and ODUCn signals
perform digital section roles only (see
[ITU-T_G709_2016]:Section 6.1.1)
b. The OTUCn signals can be viewed as being formed by interleaving n
OTUC signals (which are labeled 1, 2, ..., n), each of which has
the format of a standard OTUk signal without the FEC columns (per
[ITU-T_G709_2016]Figure 7-1). The ODUCn have a similar
structure, i.e. they can be seen as being formed by interleaving
n instances of ODUC signals (respectively). The OTUC signal
contains the ODUC signals, just as in the case of fixed rate OTUs
defined in G.709 [ITU-T_G709_2016].
c. Each of the OTUC "slices" have the same overhead as the standard
OTUk signal in G.709 [ITU-T_G709_2016]. The combined signal
OTUCn has n instances of OTUC overhead, ODUC overhead.
d. The OTUC signal has a slightly higher rate compared to the OTU4
signal (without FEC); this is to ensure that the OPUC payload
area can carry an ODU4 signal.
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As explained above, within G.709 [ITU-T_G709_2016], the OTUCn, ODUCn
and OPUCn signal structures are presented in a (physical) interface
independent manner, by means of n OTUC, ODUC and OPUC instances that
are marked #1 to #n. Specifically, the definition of the OTUCn
signal does not cover aspects such as FEC, modulation formats, etc.
These details are defined as part of the adaptation of the OTUCn
layer to the optical layer(s). The specific interleaving of
OTUC/ODUC/OPUC signals onto the optical signals is interface specific
and specified for OTN interfaces with standardized application codes
in the interface specific recommendations (G.709.x).
OTUCn interfaces can be categorized as follows, based on the type of
peer network element (see Figure 1):
a. inter-domain interfaces: These types of interfaces are used for
connecting OTN edge nodes to (a) client equipment (e.g. routers)
or (b) hand-off points from other OTN networks. ITU-T has
standardized the Flexible OTN (FlexO) interfaces to support these
functions. For example, Recommendation [ITU-T_G709.1] specifies
a flexible interoperable short-reach OTN interface over which an
OTUCn (n >=1) is transferred, using bonded FlexO interfaces which
belong to a FlexO group.
b. intra-domain interfaces: In these cases, the OTUCn is transported
using a proprietary (vendor specific) encapsulation, FEC etc. It
may also be possible to transport OTUCn for intra-domain links
using FlexO.
==================================================================
+--------------------------------------------------------+
| OTUCn signal |
+--------------------------------------------------------+
| Inter+Domain | Intra+Domain | Intra+Domain |
| Interface (IrDI)| Interface (IaDI)| Interface |
| FlexO (G.709.1) | FlexO (G.709.x) | Proprietary |
| | (Future) | Encap, FEC etc. |
+--------------------------------------------------------+
==================================================================
Figure 1: OTUCn transport possibilities
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3.2. ODUCn
The ODUCn signal [ITU-T_G709_2016] can be viewed as being formed by
the appropriate interleaving of content from n ODUC signal instances.
The ODUC frames have the same structure as a standard ODU -- in the
sense that it has the same Overhead area, and the payload area -- but
has a higher rate since its payload area can embed an ODU4 signal.
The ODUCn signals have a rate that is captured in Table 1.
+----------+--------------------------------------------------------+
| ODU Type | ODU Bit Rate |
+----------+--------------------------------------------------------+
| ODUCn | n x 239/226 x 99,532,800 kbit/s = n x 105,258,138.053 |
| | kbit/s |
+----------+--------------------------------------------------------+
Table 1: ODUCn rates
The ODUCn is a multiplex section ODU signal, and is mapped into an
OTUCn signal which provides the regenerator section layer. In some
scenarios, the ODUCn, and OTUCn signals will be co-terminated, i.e.
they will have identical source/sink locations. [ITU-T_G709_2016]
and [ITU-T_G872] allow for the ODUCn signal to pass through a digital
regenerator node which will terminate the OTUCn layer, but will pass
the regenerated (but otherwise untouched) ODUCn towards a different
OTUCn interface where a fresh OTUCn layer will be initiated (see
Figure 2). In this case, the ODUCn is carried by 3 OTUCn segments.
Specifically, the OPUCn signal flows through these regenerators
unchanged. That is, the set of client signals, their TPNs, trib-slot
allocation remains unchanged. The ODUCn Overhead might be modified
if TCM sub-layers are instantiated in order to monitor the
performance of the regenerator hops. In this sense, the ODUCn should
NOT be seen as a general ODU which can be switched via an ODUk cross-
connect.
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==================================================================
+--------+ +--------+
| +-----------+ |
| OTN |-----------| OTN |
| DXC +-----------+ DXC +
| | | |
+--------+ +--------+
<--------ODUCn------->
<-------OTUCn------>
+--------+ +--------+ +--------+ +--------+
| +--------+ | | +----------+ |
| OTN |--------| OTN | | OTN |----------| OTN |
| DXC +--------+ WXC +--------+ WXC +----------+ DXC |
| | | 3R | | 3R | | |
+--------+ +--------+ +--------+ +--------+
<-------------------------ODUCn-------------------------->
<---------------> <---------------> <------------------>
OTUCn OTUCn OTUCn
==================================================================
Figure 2: ODUCn signal
3.3. OTUCn-M
The standard OTUCn signal has the same rate as that of the ODUCn
signal as captured in Table 1. This implies that the OTUCn signal
can only be transported over wavelength groups which have a total
capacity of multiples of (approximately) 100G. Modern DSPs support a
variety of bit rates per wavelength, depending on the reach
requirements for the optical link. In other words, it is possible to
extend the reach of an optical link (i.e. increase the physical
distance covered) by lowering the bitrate of the client signal that
is modulated onto the optical signals. By the very nature of the
OTUCn signal, it is constrained to rates which are multiples of
(approximately) 100G. If it happens that the total rate of the LO-
ODUs carried over the ODUCn is smaller than n X 100G, it is possible
to "crunch" the OTUCn to remove the unused capacity. With this in
mind, ITU-T supports the notion of a reduced rate OTUCn signal,
termed the OTUCn-M. The OTUCn-M signal is derived from the OTUCn
signal by retaining all the n instances of overhead (one per OTUC
slice) but only M tributary slots of capacity.
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3.4. Time Slot Granularity
[ITU-T_G709_2012] introduced the support for 1.25G granular tributary
slots in OPU2, OPU3, and OPU4 signals. With the introduction of
higher rate signals, it is not practical for the optical networks
(and the data plane hardware) to support a very large number of
connections at such a fine granularity. ITU-T has defined the OPUC
with a tributary slot granularity of 5G. This means that the ODUCn
signal has 20*n tributary slots (of 5Gbps capacity). It is
worthwhile considering that the range of tributary port number (TPN)
is 10*n instead of 20*n, which restricts the maximum client signals
that could be carried over one single ODUC1.
3.5. Structure of OPUCn MSI with Payload type 0x22
As mentioned above, the OPUCn signal has 20*n 5G tributary slots.
The OPUCn contains n PSI structures, one per OPUC instance. The PSI
structure consists of the Payload Type (of 0x22), followed by a
Reserved Field (1 byte) and the MSI. The OPUCn MSI field has a fixed
length of 40*n bytes and indicates the availability of each TS. Two
bytes are used for each of the 20*n tributary slots, and each such
information structure has the following format ([ITU-T_G709_2016]
G.709:Section 20.4.1):
a. The TS availability bit indicates if the tributary slot is
available or unavailable
b. The TS occupation bit indicates if the tributary slot is
allocated or unallocated
c. The tributary port bits indicates the port number of the client
signal that is being carried in this specific TS. A flexible
assignment of tributary port to tributary slots is possible.
Numbering of tributary ports is from 1 to 10n.
3.6. Client Signal Mappings
The approach taken by the ITU-T to map non-OTN client signals to the
appropriate ODU containers is as follows:
a. All client signals with rates less than 100G are mapped into ODU
container as specified in clause 17 of [ITU-T_G709_2016]. These
mappings are identical to those specified in the earlier revision
of G.709 [ITU-T_G709_2012]. For example, the 1000BASE-
X/10GBASE-R signals are mapped to ODU0/ODU2e respectively (see
Table 2 -- based on Table 7-2 in [ITU-T_G709_2016])
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b. New emerging client signals are usually mapped into ODUflex
signals of the appropriate rates (see Table 2 according to the
Table 7-2 in [ITU-T_G709_2016])
c. ODU Virtual Concatenation is not supported any more. This
simplifies the network, and the supporting hardware since
multiple different mappings for the same client are no longer
necessary. Note that legacy implementations that transported
sub-100G clients using ODU VCAT shall continue to be supported.
d. ODUflex signals are low-order signals only. If the ODUflex
entities have rates of 100G or less, they can be transported over
either an ODUk (k=1..4) or an ODUCn. For ODUflex connections
with rates greater than 100G, ODUCn is required.
+----------------+--------------------------------------------------+
| ODU Type | ODU Bit Rate |
+----------------+--------------------------------------------------+
| ODU0 | 1,244,160 Kbps |
| ODU1 | 239/238 x 2,488,320 Kbps |
| ODU2 | 239/237 x 9,953,280 Kbps |
| ODU2e | 239/237 x 10,312,500 Kbps |
| ODU3 | 239/236 x 39,813,120 Kbps |
| ODU4 | 239/227 x 99,532,800 Kbps |
| ODUflex for | 239/238 x Client signal Bit rate |
| CBR client | |
| signals | |
| ODUflex for | Configured bit rate |
| GFP-F mapped | |
| packet traffic | |
| ODUflex for | s x 239/238 x 5 156 250 kbit/s: s=2,8,5*n, n >= |
| IMP mapped | 1 |
| packet traffic | |
| ODUflex for | 103 125 000 x 240/238 x n/20 kbit/s, where n is |
| FlexE aware | total number of available tributary slots among |
| transport | all PHYs which have been crunched and combined. |
+----------------+--------------------------------------------------+
Note that this table doesn't include ODUCn -- since it cannot be
generated by mapping a non-OTN signal. An ODUCn is always formed by
multiplexing multiple LO-ODUs.
Table 2: Types and rates of ODUs usable for client mappings
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==================================================================
Clients (e.g. SONET/SDH, Ethernet)
+ + +
| | |
+------------------+-------+------+------------------------+
| OPUk |
+----------------------------------------------------------+
| ODUk |
+-----------------------+---------------------------+------+
| OTUk, OTUk.V, OTUkV | OPUk | |
+----------+----------------------------------------+ |
| OTLk.n | | ODUk | |
+----------+ +---------------------+-----+ |
| OTUk, OTUk.V, OTUkV | OPUCn |
+----------+-----------------------+
| OTLk.n | | ODUCn |
+----------+ +------------+
| OTUCn |
+------------+
==================================================================
Figure 3: Digital Structure of OTN interfaces (from G.709:Figure 6-1)
4. Applicability and GMPLS Implications
4.1. Applicability and Challenges
This section analyzes the OTUCn deployment scenarios to identify
potential extensions to GMPLS that would be needed. When OTUCn links
are established between line ports of two different network elements,
two scenarios are possible. These scenarios are modeled according to
those illustrated in Appendix XIII of [ITU-T_G709_2016]. Note that
while this Appendix illustrates OTUCn subrating possibilities, the
scenarios serve a more general purpose also. Two possible
realization of OTUCn realizations between nodes are:
a. The first scenario (see Figure 4) deploys OTUCn/OTUCn-M between
two line ports connecting two L1/L0 ODU cross connects (XC)
within one optical transport network. As defined in
[ITU-T_G807], the OTUCn/OTUCn-M signal is transported using by
one OTSiG, which could be comprised of one or more OTSi. The
OTSiG may have non-associated overhead (denoted as OTSiG-O); the
combination of the OTSiG and OTSiG-O is represented by the OTSiA
management/control abstraction. There is a 1:1 mapping
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relationship between OTUCn and OTSiG or OTSiA. For example, a
400G OTUC4 signal can be carried over a single OTSi signal with a
400G capcity, or perhaps split into 4 100G digital information
streams each of which is carried over a OTSi signal with a 100G
capacity. In this scenario, it is clear that the OTUCn and ODUCn
link can be automatically established, after/together with the
setup of OTSiG or OTSiA, as both OTUCn and ODUCn perform section
layer only. Once the ODUCn link is automatically established, it
can be advertized as a TE-link and used for setting up ODUk/
ODUflex connections.
b. The second scenario (see depicted in Figure 5) deploys OTUCn/
OTUCn-M between transponders which are in a different domain B,
and are separated from the L1 ODU XCs in domain A and/or C. In
this scenario, the end-to-end ODUCn is actually supported by
three different OTUCn or OTUCn-M segments, which are in turn
carried by their respective OTSi(G) or OTSiA. In this example,
the OTUCn links will be established automatically after/together
with the setup of OTSi(G) or OTSiA. Note that until both
transponder nodes in domain B have been configured, the ODUCn
signal transmitted by node A doesn't reach node C. Until all the
required configuration operations are completed, the ODUCn.STAT
field will reflect the AIS (i.e. error) status. Once all the
provisioning has been performed in domain B, and the links
connecting the edge nodes to transponders in domain B are error
free, the end to end ODUCn flows will be established. In this
case, the receipt of a normal value for the ODUCn.STAT field can
trigger the creation of the ODUCn link.
==================================================================
+--------+ +--------+
| +---------------------+ |
| OTN |---------------------| OTN |
| XC +---------------------+ XC |
| | | |
+--------+ +--------+
<---------- ODUk/ODUflex ----------->
<------------ ODUCn -------------->
<------- OTUCn/OTUCn-M --------->
<--------OTSi(G)/OTSiA--------->
==================================================================
Figure 4: Scenario A
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==================================================================
+----------------------------+
A | B | A or C
| | | |
+--------+ | +--------+ +--------+ | +--------+
| +----------|-+ | | +-|--------+ |
| OTN |----------|-| Transp | | Transp |-|--------| OTN |
| XC +----------|-+ onder +------+ onder +-|--------+ XC |
| | | | | | | | | |
+--------+ | +--------+ +--------+ | +--------+
| |
+----------------------------+
<------------------------ODUk/ODUflex----------------------->
<------------------------ ODUCn -------------------------->
<------OTUCn------><---OTUCn/OTUCn-M---><------OTUCn------>
<-OTSi(G)/OTSiA-> <--OTSi(G)/OTSiA--> <-OTSi(G)/OTSiA->
==================================================================
Figure 5: Scenario B
4.2. GMPLS Implications and Applicability
4.2.1. TE-Link Representation
Section 3 of RFC7138 describes how to represent G.709 OTUk/ODUk with
TE-Links in GMPLS. Similar to that, ODUCn links can also be
represented as TE-Links, which can be seen in the figure below.
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==================================================================
+-----+ +-----+
| | | |
| A |<-OTUCn Link->| B |
| | | |
+-----+ +-----+
|<--- ODUCn Link -->|
|<---- TE-Link ---->|
3R 3R
+-----+ +-----+ +-----+ +-----+
| | | | | | | |
| A |<-OTUCn Link->| B |<-OTUCn Link->| C |<-OTUCn Link->| D |
| | | | | | | |
+-----+ +-----+ +-----+ +-----+
|<----------------------- ODUCn Link ------------------------>|
|<------------------------ TE-Link -------------------------->|
==================================================================
Figure 6: ODUCn TE-Links
Two endpoints of a TE-Link are configured with the supported resource
information, which may include whether the TE-Link is supported by an
ODUCn or an ODUk or an OTUk, as well as the link attribute
information (e.g., slot granularity, number of tributary slot
available).
4.2.2. Implications and Applicability for GMPLS Signalling
Once the ODUCn link is configured, the GMPLS mechanisms defined in
RFC7139 can be reused to set up ODUk/ODUflex LSP with no/few changes.
As the resource on the ODUCn link which can be seen by the client
ODUk/ODUflex is a set of 5G slots, the label defined in RFC7139 is
able to accommodate the requirement of the setup of ODUk/ODUflex over
ODUCn link. In [RFC7139], the OTN-TDM GENERALIZED_LABEL object is
used to indicate how the LO ODUj signal is multiplexed into the HO
ODUk link. In a similar manner, the OTN-TDM GENERALIZED_LABEL object
is used to indicate how the ODUk signal is multiplexed into the ODUCn
link. The ODUk Signal Type is indicated by Traffic Parameters. The
IF_ID RSVP_HOP object provides a pointer to the interface associated
with TE-Link and therefore the two nodes terminating the TE-link know
(by internal/local configuration) the attributes of the ODUCn TE
Link.
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One thing should be note is the TPN used in RFC7139 and defined in
G.709-2016 for ODUCn link. Since the TPN currently defined in G.709
for ODUCn link has 14 bits, while this field in RFC7139 only has 12
bits, some extension work is needed, but this is not so urgent since
for today networks scenarios 12 bits are enough, as it can support a
single ODUCn link up to n=400, namely 40Tbit.
An example is given below to illustrate the label format defined in
RFC7139 for multiplexing ODU4 onto ODUC10. One ODUC10 has 200 5G
slots, and twenty of them are allocated to the ODU4. Along with the
increase of "n", the label may become lengthy, an optimized label
format may be needed.
==================================================================
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TPN = 3 | Reserved | Length = 200 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 1 1 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0| Padding Bits(0) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
==================================================================
Figure 7: Label format
4.2.3. Implications and Applicability for GMPLS Routing
For routing, it is deemed that no extension to current mechanisms
defined in RFC7138 are needed. Because, once an ODUCn link is up,
the resources that need to be advertised are the resources that
exposed by this ODUCn link and the multiplexing hierarchy on this
link. Since the ODUCn link is the ultimate hierarchy of the ODU
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multiplexing, there is no need to explicitly define a new value to
represent the ODUCn signal type in the OSPF-TE routing protocol.
The OSPF-TE extension defined in section 4 of RFC7138 can be reused
to advertise the resource information on the ODUCn link to help
finish the setup of ODUk/ODUflex.
5. Acknowledgements
6. Authors (Full List)
Qilei Wang (editor)
ZTE
Nanjing, China
Email: wang.qilei@zte.com.cn
Radha Valiveti (editor)
Infinera Corp
Sunnyvale, CA, USA
Email: rvaliveti@infinera.com
Haomian Zheng (editor)
Huawei
CN
EMail: zhenghaomian@huawei.com
Huub van Helvoort
Hai Gaoming B.V
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EMail: huubatwork@gmail.com
Sergio Belotti
Nokia
EMail: sergio.belotti@nokia.com
Iftekhar Hussain
Infinera Corp
Sunnyvale, CA, USA
Email: IHussain@infinera.com
Daniele Ceccarelli
Ericsson
Email: daniele.ceccarelli@ericsson.com
7. Contributors
Rajan Rao, Infinera Corp, Sunnyvale, USA, rrao@infinera.com
Fatai Zhang, Huawei,zhangfatai@huawei.com
Italo Busi, Huawei,italo.busi@huawei.com
Zheyu Fan, Individual, zheyu2008@gmail.com
Dieter Beller, Nokia, Dieter.Beller@nokia.com
Yuanbin Zhang, ZTE, Beiing, zhang.yuanbin@zte.com.cn
Zafar Ali, Cisco Systems, zali@cisco.com
Daniel King, d.king@lancaster.ac.uk
Manoj Kumar, Cisco Systems, manojk2@cisco.com
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Antonello Bonfanti, Cisco Systems, abonfant@cisco.com
Akshaya Nadahalli, Individual, nadahalli@gmail.com
8. IANA Considerations
This memo includes no request to IANA.
9. Security Considerations
None.
10. Normative References
[ITU-T_G709.1]
ITU-T, "ITU-T G.709.1: Flexible OTN short-reach interface;
2016", , 2016.
[ITU-T_G709_2012]
ITU-T, "ITU-T G.709: Optical Transport Network Interfaces;
02/2012", http://www.itu.int/rec/T-REC-
G..709-201202-S/en, February 2012.
[ITU-T_G709_2016]
ITU-T, "ITU-T G.709: Optical Transport Network Interfaces;
07/2016", http://www.itu.int/rec/T-REC-
G..709-201606-P/en, July 2016.
[ITU-T_G807]
ITU-T, "ITU-T G.807: Generic functional architecture of
the optical media network;
2020", http://www.itu.int/rec/T-REC-G.872/en, February
2020.
[ITU-T_G872]
ITU-T, "ITU-T G.872: The Architecture of Optical Transport
Networks; 2017", http://www.itu.int/rec/T-REC-G.872/en,
January 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
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[RFC7138] Ceccarelli, D., Ed., Zhang, F., Belotti, S., Rao, R., and
J. Drake, "Traffic Engineering Extensions to OSPF for
GMPLS Control of Evolving G.709 Optical Transport
Networks", RFC 7138, DOI 10.17487/RFC7138, March 2014,
<https://www.rfc-editor.org/info/rfc7138>.
[RFC7139] Zhang, F., Ed., Zhang, G., Belotti, S., Ceccarelli, D.,
and K. Pithewan, "GMPLS Signaling Extensions for Control
of Evolving G.709 Optical Transport Networks", RFC 7139,
DOI 10.17487/RFC7139, March 2014,
<https://www.rfc-editor.org/info/rfc7139>.
[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>.
Authors' Addresses
Qilei Wang (editor)
ZTE Corporation
Nanjing
CN
Email: wang.qilei@zte.com.cn
Radha Valiveti (editor)
Infinera Corp
Sunnyvale
USA
Email: rvaliveti@infinera.com
Haomian Zheng (editor)
Huawei
CN
Email: zhenghaomian@huawei.com
Huub van Helvoort
Hai Gaoming B.V
Email: huubatwork@gmail.com
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Sergio Belotti
Nokia
Email: sergio.belotti@nokia.com
Wang, et al. Expires September 7, 2020 [Page 19]