CCAMP Working Group I. Busi
Internet Draft Huawei
Intended status: Informational D. King
Lancaster University
H. Zheng
Huawei
Y. Xu
CAICT
Expires: May 2019 November 4, 2018
Transport Northbound Interface Applicability Statement
draft-ietf-ccamp-transport-nbi-app-statement-04
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Abstract
Transport network domains, including Optical Transport Network (OTN)
and Wavelength Division Multiplexing (WDM) networks, are typically
deployed based on a single vendor or technology platforms. They are
often managed using proprietary interfaces to dedicated Element
Management Systems (EMS), Network Management Systems (NMS) and
increasingly Software Defined Network (SDN) controllers.
A well-defined open interface to each domain management system or
controller is required for network operators to facilitate control
automation and orchestrate end-to-end services across multi-domain
networks. These functions may be enabled using standardized data
models (e.g. YANG), and appropriate protocol (e.g., RESTCONF).
This document analyses the applicability of the YANG models being
defined by IETF (TEAS and CCAMP WGs in particular) to support OTN
single and multi-domain scenarios.
Table of Contents
1. Introduction...................................................4
1.1. The scope of this document................................4
1.2. Assumptions...............................................5
2. Terminology....................................................6
3. Conventions used in this document..............................7
3.1. Topology and traffic flow processing......................7
3.2. JSON code.................................................8
4. Scenarios Description..........................................9
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4.1. Reference Network.........................................9
4.1.1. Single-Domain Scenario..............................12
4.2. Topology Abstractions....................................12
4.3. Service Configuration....................................14
4.3.1. ODU Transit.........................................15
4.3.2. EPL over ODU........................................16
4.3.3. Other OTN Clients Services..........................17
4.3.4. EVPL over ODU.......................................18
4.3.5. EVPLAN and EVPTree Services.........................19
4.3.6. Dynamic Service Configuration.......................20
4.4. Multi-function Access Links..............................21
4.5. Protection and Restoration Configuration.................22
4.5.1. Linear Protection (end-to-end)......................22
4.5.2. Segmented Protection................................23
4.5.3. End-to-End Dynamic restoration......................24
4.5.4. Segmented Dynamic Restoration.......................25
4.6. Service Modification and Deletion........................25
4.7. Notification.............................................25
4.8. Path Computation with Constraint.........................26
5. YANG Model Analysis...........................................27
5.1. YANG Models for Topology Abstraction.....................27
5.1.1. Domain 1 Black Topology Abstraction.................28
5.1.2. Domain 2 Black Topology Abstraction.................30
5.1.3. Domain 3 White Topology Abstraction.................30
5.1.4. Multi-domain Topology Stitching.....................31
5.1.5. Access Links........................................33
5.2. YANG Models for Service Configuration....................35
5.2.1. ODU Transit Service.................................37
5.2.1.1. Single Domain Example..........................39
5.2.2. EPL over ODU Service................................40
5.2.3. Other OTN Client Services...........................42
5.2.4. EVPL over ODU Service...............................42
5.3. YANG Models for Protection Configuration.................43
5.3.1. Linear Protection (end-to-end)......................43
5.3.2. Segmented Protection................................43
6. Security Considerations.......................................43
7. IANA Considerations...........................................44
8. References....................................................44
8.1. Normative References.....................................44
8.2. Informative References...................................45
9. Acknowledgments...............................................46
Appendix A. Validating a JSON fragment against a YANG Model...47
A.1. Manipulation of JSON fragments..........................47
A.2. Comments in JSON fragments..............................48
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A.3. Validation of JSON fragments: DSDL-based approach.......48
A.4. Validation of JSON fragments: why not using a XSD-based
approach......................................................49
Appendix B. Detailed JSON Examples............................50
B.1. JSON Examples for Topology Abstractions.................50
B.1.1. JSON Code: mpi1-otn-topology.json.................50
B.2. JSON Examples for Service Configuration.................66
B.2.1. JSON Code: mpi1-odu2-service-config.json..........66
B.2.2. JSON Code: mpi1-odu2-tunnel-config.json...........70
B.2.3. JSON Code: mpi1-epl-service-config.json...........70
1. Introduction
Transport of packet services are critical for a wide-range of
applications and services, including data center and LAN
interconnects, Internet service backhauling mobile backhaul and
enterprise Carrier Ethernet Services. These services are typically
setup using stovepipe NMS and EMS platforms, often requiring
propriety management platforms and legacy management interfaces. A
clear goal of operators will be to automate the setup of transport
services across multiple transport technology domains.
A common open interface (API) to each domain controller and or
management system is pre-requisite for network operators to control
multi-vendor and multi-domain networks and also enable service
provisioning coordination/automation. This can be achieved by using
standardized YANG models, used together with an appropriate protocol
(e.g., [RFC8040]).
This document analyses the applicability of the YANG models being
defined by IETF (TEAS and CCAMP WGs in particular) to support OTN
single and multi-domain scenarios.
1.1. The scope of this document
This document assumes a reference architecture, including interfaces,
based on the Abstraction and Control of Traffic-Engineered Networks
(ACTN), defined in [RFC8453].
The focus of this document is on the MPI (interface between the Multi
Domain Service Coordinator (MDSC) and a Physical Network Controller
(PNC), controlling a transport network domain).
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It is worth noting that the same MPI analyzed in this document could
be used between hierarchical MDSC controllers, as shown in Figure 4
of [RFC8453].
Detailed analysis of the CMI (interface between the Customer Network
Controller (CNC) and the MDSC) as well as of the interface between
service and network orchestrators are outside the scope of this
document. However, some considerations and assumptions about the
information could be described when needed.
The relationship between the current IETF YANG models and the type of
ACTN interfaces can be found in [ACTN-YANG]. Therefore, it considers
the TE Topology YANG model defined in [TE-TOPO], with the OTN
Topology augmentation defined in [OTN-TOPO] and the TE Tunnel YANG
model defined in [TE-TUNNEL], with the OTN Tunnel augmentation
defined in [OTN-TUNNEL].
The ONF Technical Recommendations for Functional Requirements for the
transport API in [ONF TR-527] and the ONF transport API multi-domain
examples in [ONF GitHub] have been considered as input for defining
the reference scenarios analyzed in this document.
1.2. Assumptions
This document is making the following assumptions, still to be
validated with TEAS WG:
1. The MDSC can request, at the MPI, a PNC to setup a Transit Tunnel
Segment using the TE Tunnel YANG model: in this case, since the
endpoints of the E2E Tunnel are outside the domain controlled by
that PNC, the MDSC would not specify any source or destination TTP
(i.e., it would leave the source, destination, src-tp-id and dst-
tp-id attributes empty) for the tunnel and it would use the
explicit-route-object/route-object-include-exclude list to specify
the ingress and egress links for each path of the Transit Tunnel
Segment.
2. Each PNC provides to the MDSC, at the MPI, the list of available
timeslots on the inter-domain links using the TE Topology YANG
model and OTN Topology augmentation. The TE Topology YANG model in
[TE-TOPO] is being updated to report the label set information.
This document is also making the following assumptions, still to be
validated with CCAMP WG:
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1. The topology information for the Ethernet access links is modelled
using the YANG model defined in [CLIENT-TOPO].
2. The service information for Ethernet and other OTN client layer
services are modelled using the YANG model defined in [Client-
Signal].
Finally, the Network Elements (NEs) described in the scenarios used
in document are using ODU switching. It is assumed that the ODU links
are pre-configured and using mechanisms such as WDM wavelength, which
are outside the scope of this document.
2. Terminology
Domain: defined as a collection of network elements within a common
realm of address space or path computation responsibility [RFC5151]
E-LINE: Ethernet Line
EPL: Ethernet Private Line
EVPL: Ethernet Virtual Private Line
OTN: Optical Transport Network
Service: A service in the context of this document can be considered
as some form of connectivity between customer sites across the
network operator's network [RFC8309]
Service Model: As described in [RFC8309] it describes a service and
the parameters of the service in a portable way that can be used
uniformly and independent of the equipment and operating environment.
UNI: User Network Interface
MDSC: Multi-Domain Service Coordinator
CNC: Customer Network Controller
PNC: Provisioning Network Controller
MAC Bridging: Virtual LANs (VLANs) on IEEE 802.3 Ethernet network
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3. Conventions used in this document
3.1. Topology and traffic flow processing
The traffic flow between different nodes is specified as an ordered
list of nodes, separated with commas, indicating within the brackets
the processing within each node:
<node> (<processing>){, <node> (<processing>)}
The order represents the order of traffic flow being forwarded
through the network.
The processing can be either an adaptation of a client layer into a
server layer "(client -> server)" or switching at a given layer
"([switching])". Multi-layer switching is indicated by two layer
switching with client/server adaptation: "([client] -> [server])".
For example, the following traffic flow:
R1 ([PKT] -> ODU2), S3 ([ODU2]), S5 ([ODU2]), S6 ([ODU2]),
R3 (ODU2 -> [PKT])
Node R1 is switching at the packet (PKT) layer and mapping packets
into an ODU2 before transmission to node S3. Nodes S3, S5 and S6 are
switching at the ODU2 layer: S3 sends the ODU2 traffic to S5 which
then sends it to S6 which finally sends to R3. Node R3 terminates the
ODU2 from S6 before switching at the packet (PKT) layer.
The paths of working and protection transport entities are specified
as an ordered list of nodes, separated with commas:
<node> {, <node>}
The order represents the order of traffic flow being forwarded
through the network in the forward direction. In case of
bidirectional paths, the forward and backward directions are selected
arbitrarily, but the convention is consistent between
working/protection path pairs as well as across multiple domains.
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3.2. JSON code
This document provides some detailed JSON code examples to describe
how the YANG models being developed by IETF (TEAS and CCAMP WG in
particular) can be used.
The examples are provided using JSON because JSON code is easier for
humans to read and write.
Different objects need to have an identifier. The convention used to
create mnemonic identifiers is to use the object name (e.g., S3 for
node S3), followed by its type (e.g., NODE), separated by an "-",
followed by "-ID". For example, the mnemonic identifier for node S3
would be S3-NODE-ID.
JSON language does not support the insertion of comments that have
been instead found to be useful when writing the examples. This
document will insert comments into the JSON code as JSON name/value
pair with the JSON name string starting with the "//" characters. For
example, when describing the example of a TE Topology instance
representing the ODU Abstract Topology exposed by the Transport PNC,
the following comment has been added to the JSON code:
"// comment": "ODU Abstract Topology @ MPI",
The JSON code examples provided in this document have been validated
against the YANG models following the validation process described in
Appendix A, which would not consider the comments.
In order to have successful validation of the examples, some
numbering scheme has been defined to assign identifiers to the
different entities which would pass the syntax checks. In that case,
to simplify the reading, another JSON name/value pair formatted as a
comment and using the mnemonic identifiers is also provided. For
example, the identifier of node S3 (S3-NODE-ID) has been assumed to
be "10.0.0.3" and would be shown in the JSON code example using the
two JSON name/value pair:
"// te-node-id": "S3-NODE-ID",
"te-node-id": "10.0.0.3",
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The first JSON name/value pair will be automatically removed in the
first step of the validation process while the second JSON name/value
pair will be validated against the YANG model definitions.
4. Scenarios Description
4.1. Reference Network
The physical topology of the reference network is shown in Figure 1.
It represents an OTN network composed of three transport network
domains providing transport services to an IP customer network
through eight access links:
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........................
.......... : :
: : Network domain 1 : .............
Customer: : : : :
domain : : S1 -------+ : : Network :
: : / \ : : domain 3 : ..........
R1 ------- S3 ----- S4 \ : : : :
: : \ \ S2 --------+ : :Customer
: : \ \ | : : \ : : domain
: : S5 \ | : : \ : :
R2 ------+ / \ \ | : : S31 --------- R7
: : \ / \ \ | : : / \ : :
: : S6 ---- S7 ---- S8 ------ S32 S33 ------ R8
: : / | | : : / \ / : :.......
R3 ------+ | | : :/ S34 : :
: :..........|.......|...: / / : :
........: | | /:.../.......: :
| | / / :
...........|.......|..../..../... :
: | | / / : ..............
: Network | | / / : :
: domain 2 | | / / : :Customer
: S11 ---- S12 / : : domain
: / | \ / : :
: S13 S14 | S15 ------------- R4
: | \ / \ | \ : :
: | S16 \ | \ : :
: | / S17 -- S18 --------- R5
: | / \ / : :
: S19 ---- S20 ---- S21 ------------ R6
: : :
:...............................: :.............
Figure 1 - Reference network
This document assumes that all the transport network switching nodes
Si are OTN switching nodes capable of switching in the electrical
domain (ODU switching) and that all the Si-Sj OTN links within the
transport network (intra-domain or inter-domain) are 100G links while
the access Ri-Sj links are 10G links. Different technologies can be
used at the access links (e.g., Ethernet, STM-n, OTN).
It is also assumed that, within the transport network, the
physical/optical interconnections supporting the Si-Sj OTN links (up
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to the OTU4 trail), are pre-configured using mechanisms which are
outside the scope of this document and are not exposed at the MPIs to
the MDSC.
The transport domain control architecture, shown in Figure 2, follows
the ACTN architecture and framework document [RFC8453], and
functional components:
--------------
| |
| CNC |
| |
--------------
|
....................|....................... CMI
|
----------------
| |
| MDSC |
| |
----------------
/ | \
/ | \
............../.....|......\................ MPIs
/ | \
/ ---------- \
/ | PNC2 | \
/ ---------- \
---------- | \
| PNC1 | ----- \
---------- ( ) ----------
| ( ) | PNC3 |
----- ( Network ) ----------
( ) ( Domain 2 ) |
( ) ( ) -----
( Network ) ( ) ( )
( Domain 1 ) ----- ( )
( ) ( Network )
( ) ( Domain 3 )
----- ( )
( )
-----
Figure 2 - Controlling Hierarchy
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The ACTN framework facilitates the detachment of the network and
service control from the underlying technology and helps the customer
express the network as desired by business needs. Therefore, care
must be taken to keep a minimal dependency on the CMI (or no
dependency at all) with respect to the network domain technologies.
The MPI instead requires some specialization according to the domain
technology.
This document assumes that the CNC controls the customer IP network
and requests, at the CMI, transport connectivity between IP routers.
The MDSC coordinates, via three MPIs, the control of a multi-domain
transport network through three PNCs.
The control interfaces within the scope of this document are the
three MPIs, while the control interface(s) between the CNC and the IP
routers is outside the scope of this document. It is also assumed
that the CMI allows the CNC to provide all the information that is
required by the MDSC to properly configure the transport connectivity
requested by the customer.
In case the CNC requests transport connectivity between IP routers
attached to different transport domains (e.g., between R1 and R5),
the MDSC coordinates the setup of a multi-domain end-to-end OTN
connection across multiple PNCs (e.g., PNC1, PNC2 and PNC3 in in
Figure 2) as well as the configuration of the client signal mapping
at the PNCs controlling the edge domains (e.g., PNC1 and PNC2 in
Figure 2).
4.1.1. Single-Domain Scenario
In case the CNC requests transport connectivity between IP routers
attached to the same transport domain (e.g., between R1 and R3 in
Figure 1), the MDSC can request the PNC controlling that domain
(e.g., PNC1 in Figure 2) to setup an intra-domain end-to-end OTN
connection and configure the client signal mapping.
Alternatively, the MDSC can just configure the client signal mapping
and let the PNC take decisions about how to implement the service
(e.g., setting up the intra-domain end-to-end OTN connection).
4.2. Topology Abstractions
Abstraction provides a selective method for representing connectivity
information within a domain. There are multiple methods to abstract a
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network topology. This document assumes the abstraction method
defined in [RFC7926]:
"Abstraction is the process of applying the policy to the available
TE information within a domain, to produce selective information
that represents the potential ability to connect across the domain.
Thus, abstraction does not necessarily offer all possible
connectivity options, but presents a general view of potential
connectivity according to the policies that determine how the
domain's administrator wants to allow the domain resources to be
used."
[RFC8453] Provides the context of topology abstraction in the ACTN
architecture and discusses a few alternatives for the abstraction
methods for both packet and optical networks. This is an important
consideration since the choice of the abstraction method impacts
protocol design and the information it carries. According to
[RFC8453], there are three types of topology:
o White topology: This is a case where the PNC provides the actual
network topology to the MDSC without any hiding or filtering. In
this case, the MDSC has the full knowledge of the underlying
network topology;
o Black topology: The entire domain network is abstracted as a
single virtual node with the access/egress links without
disclosing any node internal connectivity information;
o Grey topology: This abstraction level is between black topology
and white topology from a granularity point of view. This is an
abstraction of TE tunnels for all pairs of border nodes. We may
further differentiate from a perspective of how to abstract
internal TE resources between the pairs of border nodes:
- Grey topology type A: border nodes with TE links between them
in a full mesh fashion;
- Grey topology type B: border nodes with some internal
abstracted nodes and abstracted links.
Each PNC should provide the MDSC with a topology abstraction of the
domain's network topology.
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Each PNC provides topology abstraction of its own domain topology
independently from each other, and therefore it is possible that
different PNCs provide different types of topology abstractions.
The MPI operates on the abstract topology regardless of, and
independently from, the type of abstraction provided by the PNC.
To analyze how the MPI operates on abstract topologies independently
from the topology abstraction provided by each PNC and, therefore,
that different PNCs can provide different topology abstractions, that
the following examples are assumed:
o PNC1 provides a black topology abstraction which exposes at MPI1 a
single virtual node (representing the whole network domain 1).
o PNC2 provides a black topology abstraction which exposes at MPI2 a
single virtual node (representing the whole network domain 2).
o PNC3 provides a white topology abstraction which exposes at MPI3
all the physical nodes and links within network domain 3.
The MDSC should be capable of stitching together each abstracted
topology to build its own view of the multi-domain network topology.
The process may require suitable oversight, including administrative
configuration and trust models, but this is out of scope for this
document.
The MDSC can also provide topology abstraction of its own view of the
multi-domain network topology at its CMIs depending on the customers'
needs: it can provide different types of topology abstractions at
different CMIs.
4.3. Service Configuration
In the following scenarios, it is assumed that the CNC is capable of
requesting service connectivity from the MDSC to support IP routers
connectivity.
The type of services could depend on the type of physical links (e.g.
OTN link, ETH link or SDH link) between the routers and transport
network.
The control of different adaptations inside IP routers, Ri (PKT ->
foo) and Rj (foo -> PKT), are assumed to be performed by means that
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are not under the control of, and not visible to, the MDSC nor to the
PNCs. Therefore, these mechanisms are outside the scope of this
document.
It is just assumed that the CNC is capable of requesting the proper
configuration of the different adaptation functions inside the
customer's IP routers, by means which are outside the scope of this
document.
4.3.1. ODU Transit
The physical links interconnecting the IP routers and the transport
network can be 10G OTN links. In this case, it is assumed that the
physical/optical interconnections below the ODU layer (up to the OTU2
trail) are pre-configured using mechanisms which are outside the
scope of this document and not exposed at the MPIs between the PNCs
and the MDSC. For simplicity of the description, it is also assumed
that these interfaces are not channelized (i.e., they can only
support one ODU2).
To setup a 10Gb IP link between R1 and R5, an ODU2 end-to-end
connection needs be created in the data plane between R1 and R5,
through transport nodes S3, S1, S2, S31, S33, S34, S15 and S18 which
belong to different PNC domains (multi-domain service request):
R1 ([PKT] -> ODU2), S3 ([ODU2]), S1 ([ODU2]), S2 ([ODU2]),
S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
S15 ([ODU2]), S18 ([ODU2]), R5 (ODU2 -> [PKT])
It is assumed that, at the CMI, the CNC requests, using mechanisms
which are outside the scope of this document, the MDSC to setup of an
ODU2 transit service between the access links on S3 and S8 and that
the MDSC understands that it shall setup an ODU2 segment connection
between the access links on S3 and S18, which belongs to different
PNC domains (multi-domain service request).
To setup of a 10Gb IP link between R1 and R3, an ODU2 end-to-end
connection needs are created in the data plane between R1 and R3,
through transport nodes S3, S5 and S6 which belong to the same PNC
domain (single-domain service request):
R1 ([PKT] -> ODU2), S3 ([ODU2]), S5 ([ODU2]), S6 ([ODU2]),
R3 (ODU2 -> [PKT])
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Since the CNC is not aware of the transport network controlling
hierarchy, the mechanisms used by the CNC to request at the CMI the
MDSC to setup an ODU2 transit service are independent on whether the
service request is single-domain or multi-domain.
Based on the assumption above, the MDSC understands that it shall
setup an ODU2 segment connection between the access links on S3 and
S6, which belong to the same PNC domain (single-domain service
request) and it can just pass the request at the MPI to PNC1 to setup
a single-domain ODU2 segment connection between its access links on
S3 and S6.
4.3.2. EPL over ODU
The physical links interconnecting the IP routers and the transport
network can be Ethernet physical links.
To setup a 10Gb IP link between R1 and R5, an EPL service needs to be
created between R1 and R5, supported by an ODU2 end-to-end connection
in the data plane between transport nodes S3 and S18, through
transport nodes S1, S2, S31, S33, S34 and S15, which belong to
different PNC domains (multi-domain service request:
R1 ([PKT] -> ETH), S3 (ETH -> [ODU2]), S1 ([ODU2]),
S2 ([ODU2]), S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
S15 ([ODU2]), S18 ([ODU2] -> ETH), R5 (ETH -> [PKT])
Based on the assumptions described in section 4.3.1, the CNC requests
at the CMI the MDSC to setup an EPL service between the access links
on S3 and S8 and the MDSC understands that it shall setup an ODU2
end-to-end connection between nodes S3 and S18, which belongs to
different PNC domains (multi-domain service request). The MDSC also
understands how the adaptation functions inside nodes S3 and S18
(i.e., S3 (ETH -> [ODU2]), S18 ([ODU2] -> ETH), S18 (ETH -> [ODU2])
and S3 ([ODU2] -> ETH)) should be configured.
To setup a 10Gb IP link between R1 and R3, an EPL service needs to be
created between R1 and R3, supported by an ODU2 end-to-end connection
in the data plane between transport nodes S3 and S6, through the
transport node S5, which belong to the same PNC domain (single-domain
service request):
R1 ([PKT] -> ETH), S3 (ETH -> [ODU2]), S5 ([ODU2]),
S6 ([ODU2] -> ETH), R3 (ETH-> [PKT])
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As described in section 4.3.1, the mechanisms used by the CNC at the
CMI are independent on whether the service request is single-domain
service or multi-domain.
Based on the assumption above, the MDSC understands that it shall
setup an EPL service between the access links on S3 and S6, which
belong to the same PNC domain (single-domain service request) and it
can just pass the request at the MPI to PNC1 to setup a single-domain
EPL service its access links on S3 and S6. In this case, PNC1 can
take care of setting up the single-domain ODU2 end-to-end connection
between nodes S3 and S6 as well as of configuring the adaptation
functions on these edge nodes.
4.3.3. Other OTN Clients Services
[ITU-T G.709] defines mappings of different client layers into ODU.
Most of them are used to provide Private Line services over an OTN
transport network supporting a variety of types of physical access
links (e.g., Ethernet, SDH STM-N, Fibre Channel, InfiniBand, etc.).
The physical links interconnecting the IP routers and the transport
network can be any of these types.
In order to setup a 10Gb IP link between R1 and R5 using, for example
SDH physical links between the IP routers and the transport network,
an STM-64 Private Line service needs to be created between R1 and R5,
supported by an ODU2 end-to-end connection in the data plane between
transport nodes S3 and S18, through transport nodes S1, S2, S31, S33,
S34 and S15, which belong to different PNC domains (multi-domain
service request):
R1 ([PKT] -> STM-64), S3 (STM-64 -> [ODU2]), S1 ([ODU2]),
S2 ([ODU2]), S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
S15 ([ODU2]), S18 ([ODU2] -> STM-64), R5 (STM-64 -> [PKT])
Based on the assumptions described in section 4.3.1, the CNC requests
the CMI the MDSC to setup an STM-64 Private Line service between the
access links on S3 and S8 and the MDSC understands what to do as
described in section 4.3.2 (multi-domain service request).
To setup a 10Gb IP link between R1 and R3), an STM-64 Private Line
service needs to be created between R1 and R3 (single-domain service
request):
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R1 ([PKT] -> STM-64), S3 (STM-64 -> [ODU2]), S5 ([ODU2]),
S6 ([ODU2] -> STM-64), R3 (STM-64 -> [PKT])
As described in section 4.3.1, the mechanisms used by the CNC at the
CMI are independent on whether the service request is single-domain
or multi-domain.
As described in section 4.3.2, the MDSC can just pass the request at
the MPI to PNC1 to setup a single-domain STM-64 Private Line service
between it access links on S3 and S6.
4.3.4. EVPL over ODU
When the physical links interconnecting the IP routers and the
transport network are Ethernet physical links, it is also possible
that different Ethernet services (e.g., EVPL) can share the same
physical access link using different VLANs.
To setup two 1Gb IP links between R1 to R3 and between R1 and R5, two
EVPL services need to be created, supported by two ODU0 end-to-end
connections in the data plane respectively between transport nodes S3
and S6, through transport node S5, which belong ot the same PNC
domain (single-domain service request) and between transport nodes S3
and S18, through transport nodes S1, S2, S31, S33, S34 and S15, which
belong to different PNC domains (multi-domain service request):
R1 ([PKT] -> VLAN), S3 (VLAN -> [ODU0]), S1 ([ODU0]),
S2 ([ODU0]), S31 ([ODU0]), S33 ([ODU0]), S34 ([ODU0]),
S15 ([ODU0]), S18 ([ODU0] -> VLAN), R5 (VLAN -> [PKT])
R1 ([PKT] -> VLAN), S3 (VLAN -> [ODU0]), S5 ([ODU0]),
S6 ([ODU0] -> VLAN), R3 (VLAN -> [PKT])
Since the two EVPL services are sharing the same Ethernet physical
link between R1 and S3, different VLAN IDs are associated with
different EVPL services: for example, VLAN IDs 10 and 20
respectively.
Based on the assumptions described in section 4.3.1, the CNC requests
at the CMI the MDSC to setup these EVPL services and the MDSC
understands what to do as described in section 4.3.2.
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4.3.5. EVPLAN and EVPTree Services
When the physical links interconnecting the IP routers and the
transport network are Ethernet links, multipoint Ethernet services
(e.g., EPLAN and EPTree) can also be supported. It is also possible
that multiple Ethernet services (e.g., EVPL, EVPLAN and EVPTree)
share the same physical link using different VLANs.
Note - it is assumed that EPLAN and EPTree services can be supported
by configuring EVPLAN and EVPTree with port mapping.
Since this EVPLAN/EVPTree service can share the same Ethernet
physical links between IP routers and transport nodes (e.g., with the
EVPL services described in section 4.3.4), a different VLAN ID (e.g.,
30) can be associated with this EVPLAN/EVPTree service.
In order to setup an IP subnet between R1, R2, R3 and R5, an
EVPLAN/EVPTree service needs to be created, supported by two ODUflex
end-to-end connections respectively between S3 and S6, crossing
transport node S5, and between S3 and S18, crossing transport nodes
S1, S2, S31, S33, S34 and S15 which belong to different PNC domains.
Some MAC Bridging capabilities are also required on some nodes at the
edge of the transport network: for example, Ethernet Bridging
capabilities can be configured in nodes S3 and S6:
o MAC Bridging in node S3 is needed to select, based on the MAC
Destination Address, whether received Ethernet frames should be
forwarded to R1 or to the ODUflex terminating on node S6 or to the
other ODUflex terminating on node S18;
o MAC bridging function in node S6 is needed to select, based on the
MAC Destination Address, whether received Ethernet frames should
be sent to R2 or to R3 or to the ODUflex terminating on node S3.
In order to support an EVPTree service instead of an EVPLAN,
additional configuration of the Ethernet Bridging capabilities on the
nodes at the edge of the transport network is required.
The traffic flows between R1 and R3, between R3 and R5 and between R1
and R5 can be summarized as:
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R1 ([PKT] -> VLAN), S3 (VLAN -> [MAC] -> [ODUflex]),
S5 ([ODUflex]), S6 ([ODUflex] -> [MAC] -> VLAN),
R3 (VLAN -> [PKT])
R3 ([PKT] -> VLAN), S6 (VLAN -> [MAC] -> [ODUflex]),
S5 ([ODUflex]), S3 ([ODUflex] -> [MAC] -> [ODUflex]),
S1 ([ODUflex]), S2 ([ODUflex]), S31 ([ODUflex]),
S33 ([ODUflex]), S34 ([ODUflex]),
S15 ([ODUflex]), S18 ([ODUflex] -> VLAN), R5 (VLAN -> [PKT])
R1 ([PKT] -> VLAN), S3 (VLAN -> [MAC] -> [ODUflex]),
S1 ([ODUflex]), S2 ([ODUflex]), S31 ([ODUflex]),
S33 ([ODUflex]), S34 ([ODUflex]),
S15 ([ODUflex]), S18 ([ODUflex] -> VLAN), R5 (VLAN -> [PKT])
As described in section 4.3.2, it is assumed that the CNC is capable,
via the CMI, to request the setup of this EVPLAN/EVPTree service,
providing all the information that the MDSC needs to understand that
it need to request PNC1 to setup an ODUflex connection between nodes
S3 and S6 (single-domain service request) and it also needs to
coordinate the setup of a multi-domain ODUflex connection between
nodes S3 and S16 as well as the MAC bridging and the adaptation
functions on these edge nodes.
In case the CNC needs the setup of an EVPLAN/EVPTree service only
between R1, R2 and R3 (single-domain service request), it would
request the setup of this service in the same way as before and the
information provided at the CMI is sufficient for the MDSC to
understand that this is a single-domain service request.
The MDSC can then just request PNC1 to setup a single-domain
EVPLAN/EVPTree service between nodes S3 and S6. PNC1 can take care of
setting up the single-domain ODUflex end-to-end connection between
nodes S3 and S6 as well as of configuring the MAC bridging and the
adaptation functions on these edge nodes.
4.3.6. Dynamic Service Configuration
Given the service established in the previous sections, there is a
demand for an update of some service characteristics. A
straightforward approach would be terminate the current service and
replace with a new one. Another more advanced approach would be a
dynamic configuration, in which case there will be no interruption
for the connection.
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An example application would be updating the SLA information for a
certain connection. For example, an ODU transit connection is set up
according to section 4.3.1, with the corresponding SLA level of 'no
protection'. After the establishment of this connection, the user
would like to enhance this service by providing a restoration after
potential failure, and a request is generated on the CMI. In this
case, after receiving the request, the MDSC would need to send an
update message to the PNC, changing the SLA parameters in TE Tunnel
model. Then the connection characteristic would be changed by PNC,
and a notification would be sent to MDSC for acknowledgement.
4.4. Multi-function Access Links
Some physical links interconnecting the IP routers and the transport
network can be configured in different modes, e.g., as OTU2 or STM-64
or 10GE.
This configuration can be done a-priori by means outside the scope of
this document. In this case, these links will appear at the MPI
either as an ODU Link or as an STM-64 Link or as a 10GE Link
(depending on the a-priori configuration) and will be controlled at
the MPI as discussed in section 4.3.
It is also possible not to configure these links a-priori and give
the control to the MPI to decide, based on the service configuration,
how to configure it.
For example, if the physical link between R1 and S3 is a multi-
functional access link while the physical links between R7 and S31
and between R5 and S18 are STM-64 and 10GE physical links
respectively, it is possible to configure either an STM-64 Private
Line service between R1 and R7 or an EPL service between R1 and R5.
The traffic flow between R1 and R7 can be summarized as:
R1 ([PKT] -> STM-64), S3 (STM-64 -> [ODU2]), S1 ([ODU2]),
S2 ([ODU2]), S31 ([ODU2] -> STM-64), R3 (STM-64 -> [PKT])
The traffic flow between R1 and R5 can be summarized as:
R1 ([PKT] -> ETH), S3 (ETH -> [ODU2]), S1 ([ODU2]),
S2 ([ODU2]), S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
S15 ([ODU2]), S18 ([ODU2] -> ETH), R5 (ETH -> [PKT])
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As described in section 4.3.2, it is assumed that the CNC is capable,
via the CMI, to request the setup either an STM-64 Private Line
service between R1 and R7 or an EPL service between R1 and R5,
providing all the information that the MDSC needs to understand that
it needs to coordinate the setup of a multi-domain ODU2 connection,
either between nodes S3 and S31, or between nodes S3 and S18, as well
as the adaptation functions on these edge nodes, and in particular
whether the multi-function access link on between R1 and S3 should
operate as an STM-64 or as a 10GE link.
4.5. Protection and Restoration Configuration
Protection switching provides a pre-allocated survivability
mechanism, typically provided via linear protection methods and would
be configured to operate as 1+1 unidirectional (the most common OTN
protection method), 1+1 bidirectional or 1:n bidirectional. This
ensures fast and simple service survivability.
Restoration methods would provide the capability to reroute and
restore connectivity traffic around network faults, without the
network penalty imposed with dedicated 1+1 protection schemes.
This section describes only services which are protected with linear
protection and with dynamic restoration.
The MDSC needs to be capable of coordinating different PNCs to
configure protection switching when requesting the setup of the
protected connectivity services described in section 4.3.
Since in these service examples, switching within the transport
network domain is performed only in the OTN ODU layer. Also
protection switching within the transport network domain can only be
provided at the OTN ODU layer.
4.5.1. Linear Protection (end-to-end)
In order to protect any service defined in section 4.3 from failures
within the OTN multi-domain transport network, the MDSC should be
capable of coordinating different PNCs to configure and control OTN
linear protection in the data plane between nodes S3 and node S18.
It is assumed that the OTN linear protection is configured to with
1+1 unidirectional protection switching type, as defined in [ITU-T
G.808.1] and [ITU-T G.873.1], as well as in [RFC4427].
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In these scenarios, a working transport entity and a protection
transport entity, as defined in [ITU-T G.808.1], (or a working LSP
and a protection LSP, as defined in [RFC4427]) should be configured
in the data plane.
Two cases can be considered:
o In one case, the working and protection transport entities pass
through the same PNC domains:
Working transport entity: S3, S1, S2,
S31, S33, S34,
S15, S18
Protection transport entity: S3, S4, S8,
S32,
S12, S17, S18
o In another case, the working and protection transport entities can
pass through different PNC domains:
Working transport entity: S3, S5, S7,
S11, S12, S17, S18
Protection transport entity: S3, S1, S2,
S31, S33, S34,
S15, S18
The PNCs should be capable to report to the MDSC which is the active
transport entity, as defined in [ITU-T G.808.1], in the data plane.
Given the fast dynamic of protection switching operations in the data
plane (50ms recovery time), this reporting is not expected to be in
real-time.
It is also worth noting that with unidirectional protection
switching, e.g., 1+1 unidirectional protection switching, the active
transport entity may be different in the two directions.
4.5.2. Segmented Protection
To protect any service defined in section 4.3 from failures within
the OTN multi-domain transport network, the MDSC should be capable of
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requesting each PNC to configure OTN intra-domain protection when
requesting the setup of the ODU2 data plane connection segment.
If PNC1 provides linear protection, the working and protection
transport entities could be:
Working transport entity: S3, S1, S2
Protection transport entity: S3, S4, S8, S2
If PNC2 provides linear protection, the working and protection
transport entities could be:
Working transport entity: S15, S18
Protection transport entity: S15, S12, S17, S18
If PNC3 provides linear protection, the working and protection
transport entities could be:
Working transport entity: S31, S33, S34
Protection transport entity: S31, S32, S34
4.5.3. End-to-End Dynamic restoration
To restore any service defined in section 4.3 from failures within
the OTN multi-domain transport network, the MDSC should be capable of
coordinating different PNCs to configure and control OTN end-to-end
dynamic Restoration in the data plane between nodes S3 and node S18.
For example, the MDSC can request the PNC1, PNC2 and PNC3 to create a
service with no-protection, MDSC set the end-to-end service with the
dynamic restoration.
Working transport entity: S3, S1, S2,
S31, S33, S34,
S15, S18
When a link failure between S1 and s2 occurred in network domain 1,
PNC1 does not restore the tunnel and send the alarm notification to
the MDSC, MDSC will perform the end-to-end restoration.
Restored transport entity: S3, S4, S8,
S12, S15, S18
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4.5.4. Segmented Dynamic Restoration
To restore any service defined in section 4.3 from failures within
the OTN multi-domain transport network, the MDSC should be capable of
coordinating different PNCs to configure and control OTN segmented
dynamic Restoration in the data plane between nodes S3 and node S18.
Working transport entity: S3, S1, S2,
S31, S33, S34,
S15, S18
When a link failure between S1 and s2 occurred in network domain 1,
PNC1 will restore the tunnel and send the alarm or tunnel update
notification to the MDSC, MDSC will update the restored tunnel.
Restored transport entity: S3, S4, S8, S2
S31, S33, S34,
S15, S18
When a link failure between network domain 1 and network domain 2
occurred, PNC1 and PNC2 will send the alarm notification to the MDSC,
MDSC will update the restored tunnel.
Restored transport entity: S3, S4, S8,
S12, S15, S18
In order to improve the efficiency of recovery, the controller can
establish a recovery path in a concurrent way. When the recovery
fails in one domain or one network element, the rollback operation
should be supported.
The creation of the recovery path by the controller can use the
method of "make-before-break", in order to reduce the impact of the
recovery operation on the services.
4.6. Service Modification and Deletion
To be discussed in future versions of this document.
4.7. Notification
To realize the topology update, service update and restoration
function, following notification type should be supported.
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1. Object create
2. Object delete
3. Object state change
4. Alarm
Because there are three types of topology abstraction type defined in
section 4.2, the notification should also be abstracted. The PNC and
MDSC should coordinate together to determine the notification policy,
such as when an intra-domain alarm occurred, the PNC may not report
the alarm but the service state change notification to the MDSC.
4.8. Path Computation with Constraint
It is possible to have constraint during path computation procedure;
typical cases include IRO/XRO and so on. This information is carried
in the TE Tunnel model and used when there is a request with
constraint. Consider the example in section 4.3.1. , the request can
be a Tunnel from R1 to R5 with an IRO from S2 to S31, then qualified
feedback would become:
R1 ([PKT] -> ODU2), S3 ([ODU2]), S1 ([ODU2]), S2 ([ODU2]),
S31 ([ODU2]), S33 ([ODU2]), S34 ([ODU2]),
S15 ([ODU2]), S18 ([ODU2]), R5 (ODU2 -> [PKT])
If the request covers the IRO from S8 to S12, then the above path
would not be qualified, while a possible computation result may be:
R1 ([PKT] -> ODU2), S3 ([ODU2]), S1 ([ODU2]), S2 ([ODU2]),
S8 ([ODU2]), S12 ([ODU2]), S15 ([ODU2]), S18 ([ODU2]), R5 (ODU2 ->
[PKT])
Similarly, the XRO can be represented by the TE tunnel model as well.
When there is a technology specific network (e.g., OTN), the
corresponding technology (OTN) model should also be used to specify
the tunnel information on MPI, with the constraint included in TE
Tunnel model.
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5. YANG Model Analysis
This section provides a high-level overview of how IETF YANG models
can be used at the MPIs, between the MDSC and the PNCs, to support
the scenarios described in section 4.
Section 5.1 describes the different topology abstractions provided to
the MDSC by each PNC via its own MPI.
Section 5.2 describes how the MDSC can coordinate different requests
to different PNCs, via their own MPIs, to setup the different
services described in section 4.3.
Section 5.3 describes how the protection scenarios can be deployed,
including end-to-end protection and segment protection, for both
intra-domain and inter-domain scenario.
5.1. YANG Models for Topology Abstraction
Each PNC reports its respective abstract topology to the MDSC, as
described in section 4.2.
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5.1.1. Domain 1 Black Topology Abstraction
PNC1 provides the required black topology abstraction, as described
in section 4.2, to expose to the MDSC, at MPI1, one TE Topology
instance for the ODU layer (MPI1 OTN Topology) containing only one
abstract TE node (i.e., AN1) and only inter-domain and access
abstract TE links (which represent the inter-domain and access
physical links), as shown in Figure 3 below.
...................................
: :
: +-----------------+ :
: | | :
(R1)- - --------| |-------- - -(S31)
: AN1-1 | | AN1-2 :
: | | :
(R2)- - --------| | :
: AN1-3 | AN1 | :
: | | :
(R3)- - --------| |-------- - -(S32)
: AN1-7 | | AN1-4 :
: | | :
: +-----------------+ :
: | | :
: AN1-6 | | AN1-5 :
:..........|..........|...........:
| |
(S11) (S12)
Figure 3 - Abstract Topology exposed at MPI1 (MPI1 OTN Topology)
As described in section 4.1, it is assumed that the physical links
between the physical nodes are pre-configured and therefore PNC1
exports at MPI1 one abstract TE Link, within the MPI1 OTN topology,
for each OTU2 or OTU4 trail which support an abstract TE link in the
MPI1 ODU Topology.
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..................................
: :
: ODU Abstract Topology @ MPI :
: Gotham City Area :
: Metro Transport Network :
: :
: +----+ +----+ :
: | |S1-1 | |S2-1:
: | S1 |--------| S2 |----- - -(S31)
: +----+ S2-2+----+ :
: S1-2/ |S2-3 :
: S3-2/ Robinson Park | :
: +----+ +----+ | :
: | |3 1| | | :
(R1)- - -----| S3 |---| S4 | | :
:S3-1+----+ +----+ | :
: S3-4 \ \S4-2 | :
: \S5-1 \ | :
: +----+ \ | :
: | | \S8-3| :
: | S5 | \ | :
: +----+ Metro \ |S8-2 :
(R2)- - ------ 2/ E \3 Main \ | :
:S6-1 \ /3 a E \1 Ring \| :
: +----+s-n+----+ +----+ :
: | |t d| | | |S8-1:
: | S6 |---| S7 |---| S8 |----- - -(S32)
: +----+4 2+----+3 4+----+ :
: / | | :
(R3)- - ------ S7-4 | | S8-5 :
:S6-2 | | :
:...............|........|.......:
| |
(S11) (S12)
Figure 4 - Physical Topology discovered by PNC1
LTP mapping table:
AN1-1 -> S3-1
AN1-2 -> S2-1
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AN1-3 -> S6-1
AN1-4 -> S8-1
AN1-5 -> S8-5
AN1-6 -> S7-4
AN1-7 -> S6-2
Appendix B.1.1 provides the detailed JSON code example ("mpi1-otn-
topology.json") describing how this ODU Topology is reported by the
PNC, using the [TE-TOPO] and [OTN-TOPO] YANG models at MPI1.
It is worth noting that this JSON code example does not provide all
the attributes defined in the relevant YANG models:
o YANG attributes which are outside the scope of this document are
not shown
o The attributes describing the label restrictions are also not
shown to simplify the JSON code example
o The comments describing the rationale for not including some
attributes in this JSON code example even if in the scope of this
document are identified with the prefix "// __COMMENT__" and
included only in the first object instance (e.g., in the Access
Link from the AN1-1 description or in the AN1-1 LTP description)
5.1.2. Domain 2 Black Topology Abstraction
PNC2 provides the required black topology abstraction, as described
in section 4.2, to expose to the MDSC, at MPI2, one TE Topology
instance for the ODU layer (MPI2 OTN Topology) containing only one
abstract node (i.e., AN2) and only inter-domain and access abstract
TE links (which represent the inter-domain and access physical
links).
5.1.3. Domain 3 White Topology Abstraction
PNC3 provides the required white topology abstraction, as described
in section 4.2, to expose to the MDSC, at MPI3, one TE Topology
instance for the ODU layer (MPI3 OTN Topology) containing one
abstract TE node for each physical node and one abstract TE link for
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each physical link (internal links, inter-domain links or access
links).
5.1.4. Multi-domain Topology Stitching
As assumed at the beginning of this section, MDSC does not have any
knowledge of the topologies of each domain until each PNC reports its
own abstraction topology, so the MDSC needs to merge together the
abstract topologies provided by different PNCs, at the MPIs, to build
its own topology view, as described in section 4.3 of [TE-TOPO].
Given the topologies reported from multiple PNCs, the MDSC need to
stitch the multi-domain topology and obtain the full map of topology.
The topology of each domain may be in an abstracted shape (refer to
section 5.2 of [RFC8453] for a different level of abstraction), while
the inter-domain link information must be complete and fully
configured by the MDSC.
The inter-domain link information is reported to the MDSC by the two
PNCs, controlling the two ends of the inter-domain link.
The MDSC needs to understand how to "stitch" together these inter-
domain links.
One possibility is to use the plug-id information, defined in [TE-
TOPO]: two inter-domain links reporting the same plug-id value can be
merged as a single intra-domain link within any MDSC native topology.
The value of the reported plug-id information can be either assigned
by a central network authority, and configured within the two PNC
domains, or it can be discovered using automatic discovery mechanisms
(e.g., LMP-based, as defined in [RFC6898]).
In case the plug-id values are assigned by a central authority, it is
under the central authority responsibility to assign unique values.
In case the plug-id values are automatically discovered, the
information discovered by the automatic discovery mechanisms needs to
be encoded as a bit string within the plug-id value. This encoding is
implementation specific, but the encoding rules need to be consistent
across all the PNCs.
In case of co-existence within the same network of multiple sources
for the plug-id (e.g., central authority and automatic discovery or
even different automatic discovery mechanisms), it is needed that the
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plug-id namespace is partitioned to avoid that different sources
assign the same plug-id value to different inter-domain link. The
encoding of the plug-id namespace within the plug-id value is
implementation specific but needs to be consistent across all the
PNCs.
Another possibility is to pre-configure, either in the adjacent PNCs
or in the MDSC, the association between the inter-domain link
identifiers (topology-id, node-id and tp-id) assigned by the two
adjacent PNCs to the same inter-domain link.
This last scenario requires further investigation and will be
discussed in a future version of this document.
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........................
: :
: Network domain 1 : .............
: Grey Topology : : :
: Abstraction : : Network :
: : : domain 3 :
(R1)- - -------+ : : (White) :
: \ +--------------+ :
: \ / : : \ :
: \ / : : \ :
(R2)- - --------- AN1 --+ : : S31 ---- - (R7)
: /|\ \ : : / \ : :
: / | \ +--------- S32 S33 - - (R8)
: / | \ : :/ \ / :
(R3)- - -------+ | +---+ : / S34 :
:..........|.......|...: /: / :
| | / :../........:
| | / /
...........|.......|.../..../....
: | | / / :
: Network | + / / :
: domain 2 | / / / :
: | / / / :
: | + / +--+ :
: | |/ / +--- - -(R4)
: Black +--- AN2 ---------+ :
: Topology | | :
: Abstraction | +-------------- - -(R5)
: | :
: +---------------- - -(R6)
: :
:...............................:
Figure 5 - Multi-domain Abstract Topology discovered by MDSC
5.1.5. Access Links
Access links in Figure 3 are shown as ODU Links: the modeling of the
access links for other access technologies is currently an open
issue.
The modeling of the access link in case of non-ODU access technology
has also an impact on the need to model ODU TTPs and layer transition
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capabilities on the edge nodes (e.g., nodes S2, S3, S6 and S8 in
Figure 3).
If, for example, the physical NE S6 is implemented in a "pizza box",
the data plane would have only set of ODU termination resources
(where up to 2xODU4, 4xODU3, 20xODU2, 80xODU1, 160xODU0 and
160xODUflex can be terminated). The traffic coming from each of the
10GE access links can be mapped into any of these ODU terminations.
Instead if, for example, the physical NE S6 can be implemented as a
multi-board system where access links reside on different/dedicated
access cards with a separated set of ODU termination resources (where
up to 1xODU4, 2xODU3, 10xODU2, 40xODU1, 80xODU0 and 80xODUflex for
each resource can be terminated). The traffic coming from one 10GE
access links can be mapped only into the ODU terminations which
reside on the same access card.
The more generic implementation option for a physical NE (e.g., S6)
would be the case is of a multi-board system with multiple access
cards with separated sets of access links and ODU termination
resources (where up to 1xODU4, 2xODU3, 10xODU2, 40xODU1, 80xODU0 and
80xODUflex for each resource can be terminated). The traffic coming
from each of the 10GE access links on one access card can be mapped
only into any of the ODU terminations which reside on the same access
card.
In the last two cases, only the ODUs terminated on the same access
card where the access links reside can carry the traffic coming from
that 10GE access link. Terminated ODUs can instead be sent to any of
the OTU4 interfaces
In all these cases, terminated ODUs can be sent to any of the OTU4
interfaces assuming the implementation is based on a non-blocking ODU
cross-connect.
If the access links are reported via MPI in some, still to be
defined, client topology, it is possible to report each set of ODU
termination resources as an ODU TTP within the ODU Topology of Figure
3 and to use either the inter-layer lock-id or the transitional link,
as described in sections 3.4 and 3.10 of [TE-TOPO], to correlate the
access links, in the client topology, with the ODU TTPs, in the OTN
topology, to which access link are connected to.
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5.2. YANG Models for Service Configuration
The service configuration procedure is assumed to be initiated (step
1 in Figure 6) at the CMI from CNC to MDSC. Analysis of the CMI
models is (e.g., L1SM, L2SM, Transport-Service, VN, et al.) is
outside the scope of this document.
As described in section 4.3, it is assumed that the CMI YANG models
provide all the information that allows the MDSC to understand that
it needs to coordinate the setup of a multi-domain ODU connection (or
connection segment) and, when needed, also the configuration of the
adaptation functions in the edge nodes belonging to different
domains.
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|
| {1}
V
----------------
| {2} |
| {3} MDSC |
| |
----------------
^ ^ ^
{3.1} | | |
+---------+ |{3.2} |
| | +----------+
| V |
| ---------- |{3.3}
| | PNC2 | |
| ---------- |
| ^ |
V | {4.2} |
---------- V |
| PNC1 | ----- V
---------- (Network) ----------
^ ( Domain 2) | PNC3 |
| {4.1} ( _) ----------
V ( ) ^
----- C==========D | {4.3}
(Network) / ( ) \ V
( Domain 1) / ----- \ -----
( )/ \ (Network)
A===========B \ ( Domain 3)
/ ( ) \( )
AP-1 ( ) X===========Z
----- ( ) \
( ) AP-2
-----
Figure 6 - Multi-domain Service Setup
As an example, the objective in this section is to configure a
transport service between R1 and R5. The cross-domain routing is
assumed to be R1 <-> S3 <-> S2 <-> S31 <-> S33 <-> S34 <->S15 <-> S18
<-> R5.
According to the different client signal type, there is different
adaptation required.
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After receiving such request, MDSC determines the domain sequence,
i.e., domain 1 <-> domain 2 <-> domain 3, with corresponding PNCs and
inter-domain links (step 2 in Figure 6).
As described in [PATH-COMPUTE], the domain sequence can be determined
by running the MDSC own path computation on the MDSC internal
topology, defined in section 5.1.4, if and only if the MDSC has
enough topology information. Otherwise, the MDSC can send path
computation requests to the different PNCs (steps 2.1, 2.2 and 2.3 in
Figure 6) and use this information to determine the optimal path on
its internal topology and therefore the domain sequence.
The MDSC will then decompose the tunnel request into a few tunnel
segments via tunnel model (including both TE tunnel model and OTN
tunnel model), and request different PNCs to setup each intra-domain
tunnel segment (steps 3, 3.1, 3.2 and 3.3 in Figure 6).
Assume that each intra-domain tunnel segment can be set up
successfully, and each PNC response to the MDSC respectively. Based
on each segment, MDSC will take care of the configuration of both the
intra-domain tunnel segment and inter-domain tunnel via corresponding
MPI (via TE tunnel model and OTN tunnel model). More specifically,
for the inter-domain configuration, the ts-bitmap and tpn attributes
need to be configured using the OTN Tunnel model. Then the end-to-end
OTN tunnel will be ready.
In any case, the access link configuration is done only on the PNCs
that control the access links (e.g., PNC-1 and PNC-3 in our example)
and not on the PNCs of transit domain (e.g., PNC-2 in our example).
An access link will be configured by MDSC after the OTN tunnel is set
up. Access configuration is different and dependent on the different
type of service. More details can be found in the following sections.
5.2.1. ODU Transit Service
In this scenario, described in section 4.3.1, the access links are
configured as ODU Links.
Since it is assumed that the physical access links are pre-
configured, each PNC exposes, at its MPI, one TE Link (called "ODU
Link") for each of these physical access link. These links are
reported, together with any other ODU internal or inter-domain link,
within the OTN abstract topology exposed by each PNC, at its own MPI.
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To setup this IP link, between R1 and R5, the CNC requests, at the
CMI, the MDSC to setup an ODU transit service.
From the topology information described in section 5.1 above, the
MDSC understands that R1 is attached to the access link terminating
on S3-1 LTP in the ODU Topology exposed by PNC1 and that R5 is
attached to the access link terminating on AN2-1 LTP in the ODU
Topology exposed by PNC2.
MDSC would then request, at MPI1, the PNC1 to setup an ODU2 (Transit
Segment) Tunnel with one primary path between S3-1 and S2-1 LTPs:
o Source and Destination TTPs are not specified (since it is a
Transit Tunnel)
o Ingress and egress points are indicated in the route-object-
include-exclude list of the explicit-route-objects of the primary
path:
o The first element references the access link terminating on
S3-1 LTP
o The last two element references respectively the inter-domain
link terminating on S2-1 LTP and the data plane resources
(i.e., the timeslots and the TPN, called "OTN Label") used by
the ODU2 connection over that link.
The configuration of the timeslots used by the ODU2 connection on the
internal links within a PNC domain (i.e., on the internal links
domain) is outside the scope of this document since it is a matter of
the PNC domain internal implementation.
However, the configuration of the timeslots used by the ODU2
connection at the transport network domain boundaries (e.g., on the
inter-domain links) needs to take into account the timeslots
available on physical nodes belonging to different PNC domains (e.g.,
on node S2 within PNC1 domain and on node S31 within PNC3 domain).
The MDSC, when coordinating the setup of a multi-domain ODU
connection, also configures the data plane resources (i.e., the
timeslots and the TPN) to be used on the inter-domain links. The MDSC
can know the timeslots which are available on the physical OTN nodes
terminating the inter-domain links (e.g., S2 and S31) from the OTN
Topology information exposed, at the MPIs, by the PNCs controlling
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the OTN physical nodes (e.g., PNC1 and PNC3 controlling the physical
nodes S2 and S31 respectively).
Appendix B.2.1 provides the detailed JSON code ("mpi1-odu2-service-
config.json") describing how the setup of this ODU2 (Transit Segment)
Tunnel can be requested by the MDSC, using the [TE-TUNNEL] and [OTN-
TUNNEL] YANG models at MPI1.
The Transport PNC performs path computation and sets up the ODU2
cross-connections within the physical nodes S3, S5 and S6, as shown
in section 4.3.1.
5.2.1.1. Single Domain Example
To setup an ODU2 end-to-end connection, supporting an IP link,
between R1 and R3, the CNC requests, at the CMI, the MDSC to setup an
ODU transit service.
The Transport PNC reports the status of the created ODU2 (Transit
Segment) Tunnel and its path within the ODU Topology as shown in
Figure 7 below:
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..................................
: :
: ODU Abstract Topology @ MPI :
: :
: +----+ +----+ :
: | | | | :
: | S1 |--------| S2 |- - - - -(R4)
: +----+ +----+ :
: / | :
: / | :
: +----+ +----+ | :
: | | | | | :
(R1)- - - - - S3 |---| S4 | | :
:S3-1 <<= + +----+ | :
: = \ | :
: = \ \ | :
: == ---+ \ | :
: = | \ | :
: = S5 | \ | :
: == --+ \ | :
(R2)- - - - - = \ \ | :
:S6-1 \ / = \ \ | :
: +--- = +----+ +----+ :
: | = | | | | :
: | S6 = --| S7 |---| S8 |- - - - -(R5)
: +--- = +----+ +----+ :
: / = :
(R3)- - - - - <<== :
:S6-2 :
:................................:
Figure 7 - ODU2 Transit Tunnel
5.2.2. EPL over ODU Service
In this scenario, described in section 4.3.2, the access links are
configured as Ethernet Links.
To setup this IP link, between R1 and R5, the CNC requests, at the
CMI, the MDSC to setup an EPL service.
As described in section 5.1.5 above, it is not clear in this case how
the Ethernet access links between the transport network and the IP
router, are reported by the PNC to the MDSC.
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If the 10GE physical links are not reported as ODU links within the
OTN topology information, described in section 5.1.1 above than the
MDSC will not have sufficient information to know that R1 and R5 are
attached to the access links terminating on S3 and S6.
Assuming that the MDSC knows how R1 and R3 are attached to the
transport network, the MDSC would request the Transport PNC to setup
an ODU2 end-to-end Tunnel between S3 and S6.
This ODU Tunnel is setup between two TTPs of nodes S3 and S6. In case
of nodes S3 and S6 support more than one TTP, the MDSC should decide
which TTP to use.
As discussed in 5.1.5, depending on the different hardware
implementations of the physical nodes S3 and S6, not all the access
links can be connected to all the TTPs. The MDSC should therefore
select not only the optimal TTP but also a TTP that would allow the
Tunnel to be used by the service.
It is assumed that in case of node S3 or node S6 supports only one
TTP, this TTP can be accessed by all the access links.
Appendix B.2.2 provides the detailed JSON code ("mpi1-odu2-tunnel-
config.json") describing how the setup of this ODU2 (Head Segment)
Tunnel can be requested by the MDSC, using the [TE-TUNNEL] and [OTN-
TUNNEL] YANG models at MPI1.
Once the ODU2 Tunnel setup has been requested, unless there is a one-
to-one relationship between the S3 and S6 TTPs and the Ethernet
access links toward R1 and R3 (as in the case, described in section
5.1.5, where the Ethernet access links reside on different/dedicated
access card such that the ODU2 tunnel can only carry the Ethernet
traffic from the only Ethernet access link on the same access card
where the ODU2 tunnel is terminated), the MDSC also needs to request
the setup of an EPL service from the access links on S3 and S6,
attached to R1 and R3, and this ODU2 Tunnel.
Appendix B.2.3 provides the detailed JSON code ("mpi1-epl-service-
config.json") describing how the setup of this EPL service using the
ODU2 Tunnel can be requested by the MDSC, using the [CLIENT-SVC] YANG
model at MPI1.
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5.2.3. Other OTN Client Services
In this scenario, the access links are configured as one of the OTN
clients (e.g., STM-64) links.
As described in section 4.3.3, the CNC needs to setup an STM-64
Private Link service, supporting an IP link, between R1 and R3 and
requests this service at the CMI to the MDSC.
MDSC needs to setup an STM-64 Private Link service between R1 and R3
supported by an ODU2 end-to-end connection between S3 and S6.
As described in section 5.1.5 above, it is not clear in this case how
the access links (e.g., the STM-N access links) between the transport
network and the IP router, are reported by the PNC to the MDSC.
The same issues, as described in section 5.2.2, apply here:
o the MDSC needs to understand that R1 and R3 are connected, thought
STM-64 access links, with S3 and S6
o the MDSC needs to understand which TTPs in S3 and S6 can be
accessed by these access links
o the MDSC needs to configure the private line service from these
access links through the ODU2 tunnel
5.2.4. EVPL over ODU Service
In this scenario, the access links are configured as Ethernet links,
as described in section 5.2.2 above.
As described in section 4.3.4, the CNC needs to setup EVPL services,
supporting IP links, between R1 and R3, as well as between R1 and R4
and requests these services at the CMI to the MDSC.
MDSC needs to setup two EVPL services, between R1 and R3, as well as
between R1 and R4, supported by ODU0 end-to-end connections between
S3 and S6 and between S3 and S2 respectively.
As described in section 5.1.5 above, it is not clear in this case how
the Ethernet access links between the transport network and the IP
router, are reported by the PNC to the MDSC.
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The same issues, as described in section 5.1.5 above, apply here:
o the MDSC needs to understand that R1, R3 and R4 are connected,
thought the Ethernet access links, with S3, S6 and S2
o the MDSC needs to understand which TTPs in S3, S6 and S2 can be
accessed by these access links
o the MDSC needs to configure the EVPL services from these access
links through the ODU0 tunnels
In addition, the MDSC needs to get the information that the access
links on S3, S6 and S2 are capable of supporting EVPL (rather than
just EPL) as well as to coordinate the VLAN configuration, for each
EVPL service, on these access links (this is a similar issue as the
timeslot configuration on access links discussed in section 4.3.1
above).
5.3. YANG Models for Protection Configuration
5.3.1. Linear Protection (end-to-end)
To be discussed in future versions of this document.
5.3.2. Segmented Protection
To be discussed in future versions of this document.
6. Security Considerations
Inherently OTN networks ensure privacy and security via hard
partitioning of traffic onto dedicated circuits. The separation of
network traffic makes it difficult to intercept data transferred
between nodes over OTN-channelized links.
This document analyses the applicability of the YANG models being
defined by the IETF to support OTN single and multi-domain scenarios
There are no specific new security considerations introduced by this
document.
In OTN the (General Communication Channel) GCC is used for OAM
functions such as performance monitoring, fault detection, and
signaling. The GCC control channel should be secured using a suitable
mechanism.
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7. IANA Considerations
This document requires no IANA actions.
8. References
8.1. Normative References
[RFC7926] Farrel, A. et al., "Problem Statement and Architecture for
Information Exchange between Interconnected Traffic-
Engineered Networks", BCP 206, RFC 7926, July 2016.
[RFC4427] Mannie, E., Papadimitriou, D., "Recovery (Protection and
Restoration) Terminology for Generalized Multi-Protocol
Label Switching (GMPLS)", RFC 4427, March 2006.
[RFC8453] Ceccarelli, D., Lee, Y. et al., "Framework for Abstraction
and Control of TE Networks (ACTN)", RFC8453, August 2018.
[ITU-T G.709] ITU-T Recommendation G.709 (06/16), "Interfaces for the
optical transport network", June 2016.
[ITU-T G.808.1] ITU-T Recommendation G.808.1 (05/14), "Generic
protection switching - Linear trail and subnetwork
protection", May 2014.
[ITU-T G.873.1] ITU-T Recommendation G.873.1 (05/14), "Optical
transport network (OTN): Linear protection", May 2014.
[TE-TOPO] Liu, X. et al., "YANG Data Model for TE Topologies", draft-
ietf-teas-yang-te-topo, work in progress.
[OTN-TOPO] Zheng, H. et al., "A YANG Data Model for Optical Transport
Network Topology", draft-ietf-ccamp-otn-topo-yang, work in
progress.
[CLIENT-TOPO] Zheng, H. et al., "A YANG Data Model for Client-layer
Topology", draft-zheng-ccamp-client-topo-yang, work in
progress.
[TE-TUNNEL] Saad, T. et al., "A YANG Data Model for Traffic
Engineering Tunnels and Interfaces", draft-ietf-teas-yang-
te, work in progress.
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[PATH-COMPUTE] Busi, I., Belotti, S. et al, "Yang model for
requesting Path Computation", draft-ietf-teas-yang-path-
computation, work in progress.
[OTN-TUNNEL] Zheng, H. et al., "OTN Tunnel YANG Model", draft-ietf-
ccamp-otn-tunnel-model, work in progress.
[CLIENT-SVC] Zheng, H. et al., "A YANG Data Model for Optical
Transport Network Client Signals", draft-zheng-ccamp-otn-
client-signal-yang, work in progress.
8.2. Informative References
[RFC5151] Farrel, A. et al., "Inter-Domain MPLS and GMPLS Traffic
Engineering --Resource Reservation Protocol-Traffic
Engineering (RSVP-TE) Extensions", RFC 5151, February 2008.
[RFC6898] Li, D. et al., "Link Management Protocol Behavior
Negotiation and Configuration Modifications", RFC 6898,
March 2013.
[RFC8040] Bierman, A. et al., "RESTCONF Protocol", RFC 8040, January
2017.
[RFC8309] Wu, Q. et al., "Service Models Explained", RFC 8309,
January 2018.
[ACTN-YANG] Zhang, X. et al., "Applicability of YANG models for
Abstraction and Control of Traffic Engineered Networks",
draft-zhang-teas-actn-yang, work in progress.
[RFC-FOLD] Watsen, K. et al., "Handling Long Lines in Artwork in
Internet-Drafts and RFCs", work in progress
[ONF TR-527] ONF Technical Recommendation TR-527, "Functional
Requirements for Transport API", June 2016.
[ONF GitHub] ONF Open Transport (SNOWMASS)
https://github.com/OpenNetworkingFoundation/Snowmass-
ONFOpenTransport
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9. Acknowledgments
The authors would like to thank all members of the Transport NBI
Design Team involved in the definition of use cases, gap analysis
and guidelines for using the IETF YANG models at the Northbound
Interface (NBI) of a Transport SDN Controller.
The authors would like to thank Xian Zhang, Anurag Sharma, Sergio
Belotti, Tara Cummings, Michael Scharf, Karthik Sethuraman, Oscar
Gonzalez de Dios, Hans Bjursrom and Italo Busi for having initiated
the work on gap analysis for transport NBI and having provided
foundations work for the development of this document.
The authors would like to thank the authors of the TE Topology and
Tunnel YANG models [TE-TOPO] and [TE-TUNNEL], in particular Igor
Bryskin, Vishnu Pavan Beeram, Tarek Saad and Xufeng Liu, for their
support in addressing any gap identified during the analysis work.
The authors would like to thank Henry Yu and Aihua Guo for their
input and review of the URIs structures used within the JSON code
examples.
This document was prepared using 2-Word-v2.0.template.dot.
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Appendix A. Validating a JSON fragment against a YANG Model
The objective is to have a tool that allows validating whether a
piece of JSON code embedded in an Internet-Draft is compliant with a
YANG model without using a client/server.
A.1. Manipulation of JSON fragments
This section describes the various ways JSON fragments are used in
the I-D processing and how to manage them.
Let's call "folded-JSON" the JSON embedded in the I-D: it fits the 72
chars width and it is acceptable for it to be invalid JSON.
We then define "unfolded-JSON" a valid JSON fragment having the same
contents of the "folded-JSON " without folding, i.e. limits on the
text width. The folding/unfolding operation may be done according to
draft-kwatsen-netmod-artwork-folding. The "unfolded-JSON" can be
edited by the authors using JSON editors with the advantages of
syntax validation and pretty-printing.
Both the "folded" and the "unfolded" JSON fragments can include
comments having descriptive fields and directives we'll describe
later to facilitate the reader and enable some automatic processing.
The presence of comments in the "unfolded-JSON" fragment makes it an
invalid JSON encoding of YANG data. Therefore we call "naked JSON"
the JSON where the comments have been stripped out: not only it is
valid JSON but it is a valid JSON encoding of YANG data.
The following schema resumes these definitions:
unfold_it --> stripper -->
Folded-JSON Unfolded-JSON Naked JSON
<-- fold_it <-- author edits
<=72-chars? MUST MAY MAY
valid JSON? MAY MUST MUST
JSON-encoding MAY MAY MUST
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of YANG data
Our validation toolchain has been designed to take a JSON in any of
the three formats and validate it automatically against a set of
relevant YANG modules using available open-source tools. It can be
found at: https://github.com/GianmarcoBruno/json-yang/
A.2. Comments in JSON fragments
We found useful to introduce two kinds of comments, both defined as
key-value pairs where the key starts with "//":
- free-form descriptive comments, e.g."// COMMENT" : "refine this" to
describe properties of JSON fragments.
- machine-usable directives e.g. "// __REFERENCES__DRAFTS__" : {
"ietf-routing-types@2017-12-04": "rfc8294",} which can be used to
automatically download from the network the relevant I-Ds or RFCs and
extract from them the YANG models of interest. This is particularly
useful to keep consistency when the drafting work is rapidly
evolving.
A.3. Validation of JSON fragments: DSDL-based approach
The idea is to generate a JSON driver file (JTOX) from YANG, then use
it to translate JSON to XML and validate it against the DSDL schemas,
as shown in Figure 8.
Useful link: https://github.com/mbj4668/pyang/wiki/XmlJson
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(2)
YANG-module ---> DSDL-schemas (RNG,SCH,DSRL)
| |
| (1) |
| |
Config/state JTOX-file | (4)
\ | |
\ | |
\ V V
JSON-file------------> XML-file ----------------> Output
(3)
Figure 8 - DSDL-based approach for JSON code validation
In order to allow the use of comments following the convention
defined in section 3without impacting the validation process, these
comments will be automatically removed from the JSON-file that will
be validate.
A.4. Validation of JSON fragments: why not using a XSD-based approach
This approach has been analyzed and discarded because no longer
supported by pyang.
The idea is to convert YANG to XSD, JSON to XML and validate it
against the XSD, as shown in Figure 9:
(1)
YANG-module ---> XSD-schema - \ (3)
+--> Validation
JSON-file------> XML-file ----/
(2)
Figure 9 - XSD-based approach for JSON code validation
The pyang support for the XSD output format was deprecated in 1.5 and
removed in 1.7.1. However pyang 1.7.1 is necessary to work with YANG
1.1 so the process shown in Figure 9 will stop just at step (1).
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Appendix B. Detailed JSON Examples
The JSON code examples provided in this appendix have been validated
using the tools in Appendix A and folded using the tool in [RFC-
FOLD].
B.1. JSON Examples for Topology Abstractions
B.1.1. JSON Code: mpi1-otn-topology.json
This is the JSON code reporting the OTN Topology @ MPI:
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========== NOTE: '\\' line wrapping per BCP XX (RFC XXXX) ===========
{
"// __TITLE__": "ODU Black Topology @ MPI1",
"// __LAST_UPDATE__": "October 18, 2018",
"// __MISSING_ATTRIBUTES__": true,
"// __REFERENCE_DRAFTS__": {
"ietf-routing-types@2017-12-04": "rfc8294",
"ietf-otn-types@2017-10-30": "draft-ietf-ccamp-otn-tunnel-model-\
\01",
"ietf-network@2018-02-26": "rfc8345",
"ietf-network-topology@2018-02-26": "rfc8345",
"ietf-te-types@2018-06-12": "draft-ietf-teas-yang-te-15",
"ietf-te-topology@2018-06-15": "draft-ietf-teas-yang-te-topo-18",
"ietf-otn-topology@2017-10-30": "draft-ietf-ccamp-otn-topo-yang-\
\02"
},
"// __RESTCONF_OPERATION__": {
"operation": "GET",
"url": "http://{{PNC1-ADDR}}/restconf/data/ietf-network:networks"
},
"ietf-network:networks": {
"network": [
{
"network-id": "providerId/201/clientId/300/topologyId/otn-bl\
\ack-topology",
"network-types": {
"ietf-te-topology:te-topology": {
"ietf-otn-topology:otn-topology": {}
}
},
"ietf-te-topology:provider-id": 201,
"ietf-te-topology:client-id": 300,
"ietf-te-topology:te-topology-id": "otn-black-topology",
"// ietf-te-topology:te": "presence container requires: prov\
\ider, client and te-topology-id",
"ietf-te-topology:te": {
"name": "OTN Black Topology @ MPI1"
},
"// ietf-network:node": "Access LTPs to be reviewed in a fut\
\ure update",
"ietf-network:node": [
{
"// __NODE__:__DESCRIPTION__": {
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"name": "AN1",
"identifier": "10.0.0.1",
"type": "Abstract Node",
"physical node(s)": "whole network domain 1"
},
"node-id": "10.0.0.1",
"ietf-te-topology:te-node-id": "10.0.0.1",
"ietf-te-topology:te": {
"te-node-attributes": {
"name": "AN11",
"admin-status": "up",
"// __DISCUSS__ is-abstract": "To be discussed with \
\TE Topology authors",
"// __DISCUSS__ underlay-topology": "To be discussed\
\ with TE Topology authors"
},
"oper-status": "up",
"// __DISCUSS__ tunnel-termination-point": []
},
"ietf-network-topology:termination-point": [
{
"// __DESCRIPTION__:__LTP__": {
"name": "AN1-1 LTP",
"link type(s)": "OTU-2",
"physical node": "S3",
"unnumberd/ifIndex": 1,
"port type": "tributary port",
"connected to": "R1"
},
"tp-id": "1",
"ietf-te-topology:te-tp-id": 1,
"ietf-te-topology:te": {
"name": "AN1-1 LTP",
"admin-status": "up",
"// __DISCUSS__ interface-switching-capability": "\
\See Link attributes (teNodeId/10.0.0.1/teLinkId/1)",
"// __DISCUSS__ inter-domain-plug-id": "Access Lin\
\k",
"// __COMMENT__ inter-layer-lock-id": "Empty: OTN \
\Links are pre-configured",
"oper-status": "up",
"// __DISCUSS__ ietf-otn-topology:supported-payloa\
\d-types": "List of ODU clients?",
"// __DISCUSS__ ietf-otn-topology:client-facing": \
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\true
}
},
{
"// __DESCRIPTION__:__LTP__": {
"name": "AN1-2 LTP",
"link type(s)": "OTU-4",
"physical node": "S2",
"unnumberd/ifIndex": 1,
"port type": "inter-domain port",
"connected to": "S31"
},
"tp-id": "2",
"ietf-te-topology:te-tp-id": 2,
"ietf-te-topology:te": {
"name": "AN1-2 LTP",
"admin-status": "up",
"// __DISCUSS__ interface-switching-capability": "\
\See Link attributes (teNodeId/10.0.0.1/teLinkId/2)",
"// __DISCUSS__ inter-domain-plug-id": "Inter-doma\
\in Link",
"oper-status": "up",
"// __DISCUSS__ ietf-otn-topology:supported-payloa\
\d-types": "Empty? (inter-domain OTN link)",
"// __DEFAULT__ ietf-otn-topology:client-facing": \
\false
}
},
{
"// __DESCRIPTION__:__LTP__": {
"name": "AN1-3 LTP",
"link type(s)": "OTU-2",
"physical node": "S6",
"unnumberd/ifIndex": 1,
"port type": "tributary port",
"connected to": "R2"
},
"tp-id": "3",
"ietf-te-topology:te-tp-id": 3,
"ietf-te-topology:te": {
"name": "AN1-3 LTP",
"admin-status": "up",
"// __DISCUSS__ interface-switching-capability": "\
\See Link attributes (teNodeId/10.0.0.1/teLinkId/3)",
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"// __DISCUSS__ inter-domain-plug-id": "Access Lin\
\k",
"oper-status": "up",
"// __DISCUSS__ ietf-otn-topology:supported-payloa\
\d-types": "List of ODU clients?",
"// __DISCUSS__ ietf-otn-topology:client-facing": \
\true
}
},
{
"// __DESCRIPTION__:__LTP__": {
"name": "AN1-4 LTP",
"link type(s)": "OTU-4",
"physical node": "S8",
"unnumberd/ifIndex": 1,
"port type": "inter-domain port",
"connected to": "S32"
},
"tp-id": "4",
"ietf-te-topology:te-tp-id": 4,
"ietf-te-topology:te": {
"name": "AN1-4 LTP",
"admin-status": "up",
"// __DISCUSS__ interface-switching-capability": "\
\See Link attributes (teNodeId/10.0.0.1/teLinkId/4)",
"// __DISCUSS__ inter-domain-plug-id": "Inter-doma\
\in Link",
"oper-status": "up",
"// __DISCUSS__ ietf-otn-topology:supported-payloa\
\d-types": "Empty? (inter-domain OTN link)",
"// __DEFAULT__ ietf-otn-topology:client-facing": \
\false
}
},
{
"// __DESCRIPTION__:__LTP__": {
"name": "AN1-5 LTP",
"link type(s)": "OTU-4",
"physical node": "S8",
"unnumberd/ifIndex": 5,
"port type": "inter-domain port",
"connected to": "S12"
},
"tp-id": "5",
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"ietf-te-topology:te-tp-id": 5,
"ietf-te-topology:te": {
"name": "AN1-5 LTP",
"admin-status": "up",
"// __DISCUSS__ interface-switching-capability": "\
\See Link attributes (teNodeId/10.0.0.1/teLinkId/5)",
"// __DISCUSS__ inter-domain-plug-id": "Inter-doma\
\in Link",
"oper-status": "up",
"// __DISCUSS__ ietf-otn-topology:supported-payloa\
\d-types": "Empty? (inter-domain OTN link)",
"// __DEFAULT__ ietf-otn-topology:client-facing": \
\false
}
},
{
"// __DESCRIPTION__:__LTP__": {
"name": "AN1-6 LTP",
"link type(s)": "OTU-4",
"physical node": "S7",
"unnumberd/ifIndex": 4,
"port type": "inter-domain port",
"connected to": "S11"
},
"tp-id": "6",
"ietf-te-topology:te-tp-id": 6,
"ietf-te-topology:te": {
"name": "AN1-6 LTP",
"admin-status": "up",
"// __DISCUSS__ interface-switching-capability": "\
\See Link attributes (teNodeId/10.0.0.1/teLinkId/6)",
"// __DISCUSS__ inter-domain-plug-id": "Inter-doma\
\in Link",
"oper-status": "up",
"// __DISCUSS__ ietf-otn-topology:supported-payloa\
\d-types": "Empty? (inter-domain OTN link)",
"// __DEFAULT__ ietf-otn-topology:client-facing": \
\false
}
},
{
"// __DESCRIPTION__:__LTP__": {
"name": "AN1-7 LTP",
"link type(s)": "OTU-2",
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"physical node": "S6",
"unnumberd/ifIndex": 2,
"port type": "tributary port",
"connected to": "R3"
},
"tp-id": "7",
"ietf-te-topology:te-tp-id": 7,
"ietf-te-topology:te": {
"name": "AN1-7 LTP",
"admin-status": "up",
"// __DISCUSS__ interface-switching-capability": "\
\See Link attributes (teNodeId/10.0.0.1/teLinkId/7)",
"// __DISCUSS__ inter-domain-plug-id": "Access Lin\
\k",
"oper-status": "up",
"// __DISCUSS__ ietf-otn-topology:supported-payloa\
\d-types": "List of ODU clients?",
"// __DISCUSS__ ietf-otn-topology:client-facing": \
\true
}
}
]
}
],
"// ietf-network-topology:link": "Access links to be reviewe\
\d in a future update",
"ietf-network-topology:link": [
{
"// __DESCRIPTION__:__LINK__": {
"name": "Access Link from AN1-1",
"type": "access link",
"physical link": "Link from S3-1 to R1"
},
"link-id": "teNodeId/10.0.0.1/teLinkId/1",
"ietf-te-topology:te": {
"te-link-attributes": {
"name": "Access Link from AN1-1",
"// __DISCUSS__ access-type": "Can we assume point-t\
\o-point as the default value?",
"access-type": "point-to-point",
"// __COMMENT__ external-domain": "Empty: the plug-i\
\d is used instead of this container",
"// __DISCUSS__ is-abstract": "To be discussed with \
\TE Topology authors",
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"// __DISCUSS__ underlay": "To be discussed with TE \
\Topology authors",
"admin-status": "up",
"interface-switching-capability": [
{
"switching-capability": "ietf-te-types:switching\
\-otn",
"encoding": "ietf-te-types:lsp-encoding-oduk",
"max-lsp-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "ODU2"
}
]
}
],
"// __COMMENT__ label-restrictions": "Not described \
\in this JSON example",
"// __DISCUSS__ link-protection-type": "Can we assum\
\e unprotected as the default value?",
"link-protection-type": "unprotected",
"max-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU2"
},
"max-resv-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU2"
},
"unreserved-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "1xODU2"
}
]
},
"oper-status": "up",
"// __EMPTY__ is-transitional": "It is not a transitio\
\nal link",
"// __DISCUSS__ underlay ": "To be discussed with TE T\
\opology authors"
},
"source": {
"source-node": "10.0.0.1",
"source-tp": 1
},
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"// __EMPTY__ destination": "access link"
},
{
"// __DESCRIPTION__:__LINK__": {
"name": "Inter-domain Link from AN1-2",
"type": "inter-domain link",
"physical link": "Link from S2-1 to S31"
},
"link-id": "teNodeId/10.0.0.1/teLinkId/2",
"ietf-te-topology:te": {
"te-link-attributes": {
"name": "Inter-domain Link from AN1-2",
"// __DISCUSS__ access-type": "Can we assume point-t\
\o-point as the default value?",
"access-type": "point-to-point",
"// __DISCUSS__ is-abstract": "To be discussed with \
\TE Topology authors",
"// __DISCUSS__ underlay": "To be discussed with TE \
\Topology authors",
"admin-status": "up",
"interface-switching-capability": [
{
"switching-capability": "ietf-te-types:switching\
\-otn",
"encoding": "ietf-te-types:lsp-encoding-oduk",
"max-lsp-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "ODU4"
}
],
"// __DISCUSS__ label-restrictions": "To be adde\
\d?"
}
],
"// __DISCUSS__ link-protection-type": "Can we assum\
\e unprotected as the default value?",
"link-protection-type": "unprotected",
"max-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
},
"max-resv-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
},
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"unreserved-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
}
]
},
"oper-status": "up",
"// __EMPTY__ is-transitional": "It is not a transitio\
\nal link",
"// __DISCUSS__ underlay ": "To be discussed with TE T\
\opology authors"
},
"source": {
"source-node": "10.0.0.1",
"source-tp": 2
},
"// __EMPTY__ destination": "inter-domain link"
},
{
"// __DESCRIPTION__:__LINK__": {
"name": "Access Link from AN1-3",
"type": "access link",
"physical link": "Link from S6-1 to R2"
},
"link-id": "teNodeId/10.0.0.1/teLinkId/3",
"ietf-te-topology:te": {
"te-link-attributes": {
"name": "Access Link from AN1-3",
"// __DISCUSS__ access-type": "Can we assume point-t\
\o-point as the default value?",
"access-type": "point-to-point",
"// __DISCUSS__ is-abstract": "To be discussed with \
\TE Topology authors",
"// __DISCUSS__ underlay": "To be discussed with TE \
\Topology authors",
"admin-status": "up",
"interface-switching-capability": [
{
"switching-capability": "ietf-te-types:switching\
\-otn",
"encoding": "ietf-te-types:lsp-encoding-oduk",
"max-lsp-bandwidth": [
{
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"priority": 0,
"// __DISCUSS__ te-bandwidth": "ODU2"
}
],
"// __DISCUSS__ label-restrictions": "To be adde\
\d?"
}
],
"// __DISCUSS__ link-protection-type": "Can we assum\
\e unprotected as the default value?",
"link-protection-type": "unprotected",
"max-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU2"
},
"unreserved-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "1xODU2"
}
],
"max-resv-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU2"
}
},
"oper-status": "up",
"// __EMPTY__ is-transitional": "It is not a transitio\
\nal link",
"// __DISCUSS__ underlay ": "To be discussed with TE T\
\opology authors"
},
"source": {
"source-node": "10.0.0.1",
"source-tp": 3
},
"// __EMPTY__ destination": "access link"
},
{
"// __DESCRIPTION__:__LINK__": {
"name": "Inter-domain Link from AN1-4",
"type": "inter-domain link",
"physical link": "Link from S8-1 to S32"
},
"link-id": "teNodeId/10.0.0.1/teLinkId/4",
"ietf-te-topology:te": {
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"te-link-attributes": {
"name": "Inter-domain Link from AN1-4",
"// __DISCUSS__ access-type": "Can we assume point-t\
\o-point as the default value?",
"access-type": "point-to-point",
"// __DISCUSS__ is-abstract": "To be discussed with \
\TE Topology authors",
"// __DISCUSS__ underlay": "To be discussed with TE \
\Topology authors",
"admin-status": "up",
"interface-switching-capability": [
{
"switching-capability": "ietf-te-types:switching\
\-otn",
"encoding": "ietf-te-types:lsp-encoding-oduk",
"max-lsp-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "ODU4"
}
],
"// __DISCUSS__ label-restrictions": "To be adde\
\d?"
}
],
"// __DISCUSS__ link-protection-type": "Can we assum\
\e unprotected as the default value?",
"link-protection-type": "unprotected",
"max-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
},
"unreserved-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
}
],
"max-resv-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
}
},
"oper-status": "up",
"// __EMPTY__ is-transitional": "It is not a transitio\
\nal link",
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"// __DISCUSS__ underlay ": "To be discussed with TE T\
\opology authors"
},
"source": {
"source-node": "10.0.0.1",
"source-tp": 4
},
"// __EMPTY__ destination": "inter-domain link"
},
{
"// __DESCRIPTION__:__LINK__": {
"name": "Inter-domain Link from AN1-5",
"type": "inter-domain link",
"physical link": "Link from S8-5 to S12"
},
"link-id": "teNodeId/10.0.0.1/teLinkId/5",
"ietf-te-topology:te": {
"te-link-attributes": {
"name": "Inter-domain Link from AN1-5",
"// __DISCUSS__ access-type": "Can we assume point-t\
\o-point as the default value?",
"access-type": "point-to-point",
"// __DISCUSS__ is-abstract": "To be discussed with \
\TE Topology authors",
"// __DISCUSS__ underlay": "To be discussed with TE \
\Topology authors",
"admin-status": "up",
"interface-switching-capability": [
{
"switching-capability": "ietf-te-types:switching\
\-otn",
"encoding": "ietf-te-types:lsp-encoding-oduk",
"max-lsp-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "ODU4"
}
],
"// __DISCUSS__ label-restrictions": "To be adde\
\d?"
}
],
"// __DISCUSS__ link-protection-type": "Can we assum\
\e unprotected as the default value?",
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"link-protection-type": "unprotected",
"max-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
},
"max-resv-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
},
"unreserved-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
}
]
},
"oper-status": "up",
"// __EMPTY__ is-transitional": "It is not a transitio\
\nal link",
"// __DISCUSS__ underlay ": "To be discussed with TE T\
\opology authors"
},
"source": {
"source-node": "10.0.0.1",
"source-tp": 5
},
"// __EMPTY__ destination": "inter-domain link"
},
{
"// __DESCRIPTION__:__LINK__": {
"name": "Inter-domain Link from AN1-6",
"type": "inter-domain link",
"physical link": "Link from S7-4 to S11"
},
"link-id": "teNodeId/10.0.0.1/teLinkId/6",
"ietf-te-topology:te": {
"te-link-attributes": {
"name": "Inter-domain Link from AN1-6",
"// __DISCUSS__ access-type": "Can we assume point-t\
\o-point as the default value?",
"access-type": "point-to-point",
"// __DISCUSS__ is-abstract": "To be discussed with \
\TE Topology authors",
"// __DISCUSS__ underlay": "To be discussed with TE \
\Topology authors",
"admin-status": "up",
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"interface-switching-capability": [
{
"switching-capability": "ietf-te-types:switching\
\-otn",
"encoding": "ietf-te-types:lsp-encoding-oduk",
"max-lsp-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "ODU4"
}
],
"// __DISCUSS__ label-restrictions": "To be adde\
\d?"
}
],
"// __DISCUSS__ link-protection-type": "Can we assum\
\e unprotected as the default value?",
"link-protection-type": "unprotected",
"max-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
},
"max-resv-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
},
"unreserved-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "1xODU4, ..."
}
]
},
"oper-status": "up",
"// __EMPTY__ is-transitional": "It is not a transitio\
\nal link",
"// __DISCUSS__ underlay ": "To be discussed with TE T\
\opology authors"
},
"source": {
"source-node": "10.0.0.1",
"source-tp": 6
},
"// __EMPTY__ destination": "inter-domain link"
},
{
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"// __DESCRIPTION__:__LINK__": {
"name": "Access Link from AN1-7",
"type": "access link",
"physical link": "Link from S6-2 to R3"
},
"link-id": "teNodeId/10.0.0.1teLinkId/7",
"ietf-te-topology:te": {
"te-link-attributes": {
"name": "Access Link from AN1-7",
"// __DISCUSS__ access-type": "Can we assume point-t\
\o-point as the default value?",
"access-type": "point-to-point",
"// __DISCUSS__ is-abstract": "To be discussed with \
\TE Topology authors",
"// __DISCUSS__ underlay": "To be discussed with TE \
\Topology authors",
"admin-status": "up",
"interface-switching-capability": [
{
"switching-capability": "ietf-te-types:switching\
\-otn",
"encoding": "ietf-te-types:lsp-encoding-oduk",
"max-lsp-bandwidth": [
{
"priority": 0,
"// __DISCUSS__ te-bandwidth": "ODU2"
}
],
"// __DISCUSS__ label-restrictions": "To be adde\
\d?"
}
],
"// __DISCUSS__ link-protection-type": "Can we assum\
\e unprotected as the default value?",
"link-protection-type": "unprotected",
"max-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU2"
},
"max-resv-link-bandwidth": {
"// __DISCUSS__ te-bandwidth": "1xODU2"
},
"unreserved-bandwidth": [
{
"priority": 0,
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"// __DISCUSS__ te-bandwidth": "1xODU2"
}
]
},
"oper-status": "up",
"// __EMPTY__ is-transitional": "It is not a transitio\
\nal link",
"// __DISCUSS__ underlay ": "To be discussed with TE T\
\opology authors"
},
"source": {
"source-node": "10.0.0.1",
"source-tp": 7
},
"// __EMPTY__ destination": "access link"
}
]
}
]
}
}
B.2. JSON Examples for Service Configuration
B.2.1. JSON Code: mpi1-odu2-service-config.json
This is the JSON code reporting the ODU2 transit service
configuration @ MPI:
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========== NOTE: '\\' line wrapping per BCP XX (RFC XXXX) ===========
{
"// __TITLE__": "ODU2 Service Configuration @ MPI1",
"// __LAST_UPDATE__": "October 22, 2018",
"// __MISSING_ATTRIBUTES__": true,
"// __REFERENCE_DRAFTS__": {
"ietf-routing-types@2017-12-04": "rfc8294",
"ietf-otn-types@2018-06-07": "draft-ietf-ccamp-otn-tunnel-model-\
\02",
"ietf-te-types@2018-07-01": "draft-ietf-teas-yang-te-16",
"ietf-te@2018-07-01": "draft-ietf-teas-yang-te-16",
"ietf-otn-tunnel@2018-06-07": "draft-ietf-ccamp-otn-tunnel-model\
\-02"
},
"// __RESTCONF_OPERATION__": {
"operation": "PUT",
"url": "http://{{PNC1-ADDR}}/restconf/data/ietf-te:te"
},
"ietf-te:te": {
"tunnels": {
"tunnel": [
{
"name": "mpi1-odu2-service",
"// identifier": "ODU2-SERVICE-TUNNEL-ID @ MPI1",
"identifier": 1,
"description": "ODU2 Service implemented by ODU2 OTN Tunne\
\l Segment @ MPI1",
"// encoding and switching-type": "ODU",
"encoding": "ietf-te-types:lsp-encoding-oduk ",
"switching-type": "ietf-te-types:switching-otn",
"// source": "None: transit tunnel segment",
"// destination": "None: transit tunnel segment",
"// src-tp-id": "None: transit tunnel segment",
"// dst-tp-id": "None: transit tunnel segment",
"// ietf-otn-tunnel:src-client-signal": "None: ODU transit\
\ tunnel segment",
"// ietf-otn-tunnel:dst-client-signal": "None: ODU transit\
\ tunnel segment",
"bidirectional": true,
"// protection": "No protection",
"// __ DEFAULT __ protection": {
"// __ DEFAULT __ enable": false
},
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"// restoration": "No restoration",
"// __ DEFAULT __ restoration": {
"// __ DEFAULT __ enable": false
},
"// te-topology-identifier": "ODU Black Topology @ MPI1",
"te-topology-identifier": {
"provider-id": 201,
"client-id": 300,
"topology-id": "otn-black-topology"
},
"te-bandwidth": {
"ietf-otn-tunnel:odu-type": "ietf-otn-types:prot-ODU2"
},
"// hierarchical-link": "None: transit tunnel segment",
"p2p-primary-paths": {
"p2p-primary-path": [
{
"name": "mpi1-odu2-service-primary-path",
"path-scope": "ietf-te-types:path-scope-segment",
"// te-bandwidth": "None: only the tunnel bandwidth \
\needs to be specified in transport applications",
"explicit-route-objects": {
"route-object-include-exclude": [
{
"// comment": "Tunnel hand-off OTU2 ingress in\
\terface (S3-1)",
"index": 1,
"explicit-route-usage": "ietf-te-types:route-i\
\nclude-ero",
"num-unnum-hop": {
"// node-id": "AN1 Node",
"node-id": "10.0.0.1",
"// link-tp-id": "AN1-1 LTP",
"link-tp-id": 1,
"hop-type": "STRICT",
"direction": "INCOMING"
}
},
{
"// comment": "Tunnel hand-off ODU2 ingress la\
\bel (ODU2 over OTU2) at S3-1",
"index": 2,
"explicit-route-usage": "ietf-te-types:route-i\
\nclude-ero",
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"label-hop": {
"te-label": {
"// __ DISCUSS __ odu-label": "How are HO-\
\ODU (ODUk over OTUk) label represented?",
"// __ DISCUSS __ direction": "Check with \
\TE Tunnel authors",
"direction": "FORWARD "
}
}
},
{
"// comment": "Tunnel hand-off OTU4 egress int\
\erface (S2-1)",
"index": 3,
"explicit-route-usage": "ietf-te-types:route-i\
\nclude-ero",
"num-unnum-hop": {
"// node-id": "AN1 Node",
"node-id": "10.0.0.1",
"// link-tp-id": "AN1-2 LTP",
"link-tp-id": 1,
"hop-type": "STRICT",
"direction": "OUTGOING"
}
},
{
"// comment": "Tunnel hand-off ODU2 egress lab\
\el (ODU2 over OTU4) at S2-1",
"index": 4,
"explicit-route-usage": "ietf-te-types:route-i\
\nclude-ero",
"label-hop": {
"te-label": {
"ietf-otn-tunnel:tpn": 1,
"ietf-otn-tunnel:tsg": "ietf-otn-types:tsg\
\-1.25G",
"ietf-otn-tunnel:ts-list": "1-8",
"// __ DISCUSS __ direction": "Check with \
\TE Tunnel authors",
"direction": "FORWARD "
}
}
}
]
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}
}
]
}
}
]
}
}
}
B.2.2. JSON Code: mpi1-odu2-tunnel-config.json
The JSON code for this use case will be added in a future version of
this document
An incomplete version is located on GitHub at:
https://github.com/danielkinguk/transport-nbi
B.2.3. JSON Code: mpi1-epl-service-config.json
The JSON code for this use case will be added in a future version of
this document
An incomplete version is located on GitHub at:
https://github.com/danielkinguk/transport-nbi
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Authors' Addresses
Italo Busi (Editor)
Huawei
Email: italo.busi@huawei.com
Daniel King (Editor)
Lancaster University
Email: d.king@lancaster.ac.uk
Haomian Zheng (Editor)
Huawei
Email: zhenghaomian@huawei.com
Yunbin Xu (Editor)
CAICT
Email: xuyunbin@ritt.cn
Yang Zhao
China Mobile
Email: zhaoyangyjy@chinamobile.com
Sergio Belotti
Nokia
Email: sergio.belotti@nokia.com
Gianmarco Bruno
Ericsson
Email: gianmarco.bruno@ericsson.com
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Young Lee
Huawei
Email: leeyoung@huawei.com
Victor Lopez
Telefonica
Email: victor.lopezalvarez@telefonica.com
Carlo Perocchio
Ericsson
Email: carlo.perocchio@ericsson.com
Ricard Vilalta
CTTC
Email: ricard.vilalta@cttc.es
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