Internet DRAFT - draft-leebelotti-teas-actn-info
draft-leebelotti-teas-actn-info
Teas Working Group Young Lee
Internet Draft Huawei
Intended status: Informational Sergio Belotti
Nokia
Expires: April 2017
Dhruv Dhody
Huawei
Daniele Ceccarelli
Ericsson
Bin Young Yun
ETRI
October 24, 2016
Information Model for Abstraction and Control of TE Networks (ACTN)
draft-leebelotti-teas-actn-info-05.txt
Abstract
This draft provides an information model for Abstraction and Control
of Traffic Engineered (TE) networks (ACTN).
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This Internet-Draft will expire on April 24, 2015.
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Table of Contents
1. Introduction...................................................3
1.1. Terminology...............................................4
2. ACTN Common Interfaces Information Model.......................6
2.1. VN Action Primitives......................................7
2.1.1. VN Instantiate.......................................7
2.1.2. VN Modify............................................7
2.1.3. VN Delete............................................8
2.1.4. VN Update............................................8
2.1.5. VN Path Compute......................................8
2.1.6. VN Query.............................................9
2.1.7. TE Update (for TE resources).........................9
2.2. VN Objects...............................................10
2.2.1. VN Identifier.......................................10
2.2.2. VN Service Characteristics..........................10
2.2.3. VN End-Point........................................13
2.2.4. VN Objective Function...............................13
2.2.5. VN Action Status....................................14
2.2.6. VN Associated LSP...................................14
2.2.7. VN Computed Path....................................14
2.2.8. VN Service Preference...............................15
2.3. Mapping of VN Primitives with VN Objects.................15
3. References....................................................17
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3.1. Normative References.....................................17
3.2. Informative References...................................17
4. Contributors..................................................18
Contributors' Addresses..........................................18
Authors' Addresses...............................................18
Appendix A: ACTN Applications....................................19
A.1. Coordination of Multi-destination Service
Requirement/Policy.........................................19
A.2. Application Service Policy-aware Network Operation....21
A.3. Network Function Virtualization Service Enabled
Connectivity...............................................23
A.4. Dynamic Service Control Policy Enforcement for
Performance and Fault Management...........................25
A.5. E2E VN Survivability and Multi-Layer (Packet-Optical)
Coordination for Protection/Restoration....................26
1. Introduction
This draft provides an information model for the requirements
identified in the ACTN requirements [ACTN-Req] and the ACTN
interfaces identified in the ACTN architecture and framework
document [ACTN-Frame].
The purpose of this draft is to put all information elements of ACTN
in one place before proceeding to development work necessary for
protocol extensions and data models.
The ACTN reference architecture identified a three-tier control
hierarchy as depicted in Figure 1:
- Customer Network Controllers (CNC)
- Multi-Domain Service Coordinator (MDSC)
- Physical Network Controllers (PNC).
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+-------+ +-------+ +-------+
| CNC-A | | CNC-B | | CNC-C |
+-------+ +-------+ +-------+
\___________ | ____________ _/
---------- | CMI ------------
\ | /
+-----------------------+
| MDSC |
+-----------------------+
_________/ | \_________
-------- | MPI ------------____
/ | \
+-------+ +-------+ +-------+
| PNC | | PNC | | PNC |
+-------+ +-------+ +-------+
Figure 1: A Three-tier ACTN control hierarchy
The two interfaces with respect to the MDSC, one north of the MDSC
and the other south of the MDSC are referred to as CMI (CNC-MDSC
Interface) and MPI (MDSC-PNC Interface), respectively. It is
intended to model these two interfaces and derivative interfaces
thereof (e.g., MDSC to MSDC in a hierarchy of MDSCs) with one common
model.
Appendix A provides some relevant ACTN use-cases extracted from
[ACTN-Req]. Appendix A is information only and may help readers
understand the context of key use-cases addressed in [ACTN-Req].
1.1. Terminology
o A Virtual Network is a client view (typically a network slice)
of the transport network. It is presented by the provider as a
set of physical and/or abstracted resources. Depending on the
agreement between client and provider various VN operations and
VN views are possible. There are three aspects related to VN:
1) VN Creation: VN could be pre-configured and created via
static negotiation between customer and provider. In
other cases, VN could also be created dynamically based
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on the request from the customer with given SLA
attributes which satisfy the customer's objectives.
2) Dynamic Operations: VN could be further modified and
deleted based on customer request to request changes in
the network resources reserved for the customer. The
customer can further act upon the virtual network
resources to perform E2E tunnel management (set-
up/release/modify). These changes will incur subsequent
LSP management on the operator's level.
3) VN View: (a) VN can be seen as an (or set of) e2e
tunnel(s) from a customer point of view where an e2e
tunnel is referred as a VN member. Each VN member (i.e.,
e2e tunnel) can then be formed by recursive aggregation
of lower level paths at a provider level. Such end to end
tunnels may comprise of customer end points, access
links, intra domain paths and inter-domain link. In this
view VN is thus a list of VN members. (b) VN can also be
seen as a terms of topology comprising of physical and
abstracted nodes and links. The nodes in this case
include physical customer end points, border nodes, and
internal nodes as well as abstracted nodes. Similarly the
links includes physical access, inter-domain and intra-
domain links as well as abstracted links. The abstracted
nodes and links in this view can be pre-negotiated or
created dynamically.
o A Virtual Network Service (VNS) is the creation and offering of
a Virtual Network by a provider to a customer in accordance
with SLA agreements reached between them (e.g., re satisfying
the customer's objectives).
o Abstraction is the process of applying 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 it 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 [RFC7926].
o Abstract topology: Every lower controller in the provider
network, when is representing its network topology to a higher
layer, it may want to selective hide details of the actual
network topology, as suggested for abstraction in [RFC7926]. In
such case, an abstract topology may be used for this purpose.
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Abstract topology enhances scalability for the MDSC to operate
multi-domain networks.
2. ACTN Common Interfaces Information Model
This section provides ACTN common interface information model to
describe in terms of primitives, objects, their properties
(represented as attributes), their relationships, and the resources
for the service applications needed in the ACTN context.
Basic primitives (messages) are required between the CNC-MDSC and
MDSC-PNC controllers. These primitives can then be used to support
different ACTN network control functions like network topology
request/query, VN service request, path computation and connection
control, VN service policy negotiation, enforcement, routing
options, etc.
The standard interface is described between a client controller and
a server controller. A client-server relationship is recursive
between a CNC and a MDSC and between a MDSC and a PNC. In the CMI,
the client is a CNC while the server is a MDSC. In the MPI, the
client is a MDSC and the server is a PNC. There may also be MDSC-
MDSC interface(s) that need to be supported. This may arise in a
hierarchy of MDSCs in which workloads may need to be partitioned to
multiple MDSCs.
Basic primitives (messages) are required between the CNC-MDSC and
MDSC-PNC controllers. These primitives can then be used to support
different ACTN network control functions like network topology
request/query, VN service request, path computation and connection
control, VN service policy negotiation, enforcement, routing
options, etc.
At a minimum, the following VN action primitives should be
supported:
- VN Instantiate (See Section 2.1.1. for the description)
- VN Modify (See Section 2.1.2. for the description)
- VN Delete (See Section 2.1.3. for the description)
- VN Update ((See Section 2.1.4. for the description)
- VN Path Compute (See Section 2.1.5. for the description)
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- VN Query (See Section 2.1.6. for the description)
In addition to VN action primitives, TE Update primitive should also
be supported (See Section 2.1.7. for the description).
2.1. VN Action Primitives
This section provides a list of main primitives necessary to satisfy
ACTN requirements specified in [ACTN-REQ].
<VN Action> describes main primitives. VN Action can be one of the
following primitives: (i) VN Instantiate; (ii) VN Modify; (iii) VN
Delete; (iv) VN Update; (v) VN Path Compute; (vi) VN Query.
<VN Action> ::= <VN Instantiate> |
<VN Modify> |
<VN Delete> |
<VN Update> |
<VN Path Compute> |
<VN Query>
2.1.1. VN Instantiate
<VN Instantiate> refers to an action from customers/applications to
request their VNs. This primitive can also be applied from an MDSC
to a PNC requesting a VN (if the domain the PNC supports can
instantiate the entire VN) or a part of VN elements. Please see the
definition of VN in the section 2.
2.1.2. VN Modify
<VN Modify> refers to an action from customers/applications to
modify an existing VN (i.e., instantiated VN). This primitive can
also be applied from an MDSC to a PNC requesting a VN (if the domain
the PNC supports can instantiate the entire VN) or a part of VN
elements.
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2.1.3. VN Delete
<VN Delete> refers to an action from customers/applications to
delete an existing VN. This primitive can also be applied from an
MDSC to a PNC requesting a VN (if the domain the PNC supports can
instantiate the entire VN) or a part of VN elements.
2.1.4. VN Update
<VN Update> refers to any update to the VN that need to be updated
to the subscribers. VN Update fulfills a push model at CMI level, to
make aware customers of any specific changes in the topology details
related to VN instantiated.
Note the VN Update means the connection-related information (e.g.,
LSPs) update that has association with VNs.
2.1.5. VN Path Compute
<VN Path Compute> consists of Request and Reply. Request refers to
an action from customers/applications to request a VN path
computation. This primitive can also be applied from an MDSC to a
PNC requesting a VN (if the domain the PNC supports can instantiate
the entire VN) or a part of VN elements.
<VN Path Compute> Reply refers to the reply in response to <VN Path
Compute> Request.
<VN Path Compute> Request/Reply is to be differentiated from a VN
Instantiate. The purpose of VN Path Compute is a priori exploration
to estimate network resources availability and getting a list of
possible paths matching customer/applications constraints. To make
this type of request Customer/application controller can have a
shared (with lower controller) view of an abstract network topology
on which to get the constraints used as input in a Path Computation
request. The list of paths obtained by the request can be used by
customer/applications to give path constrains during VNS
connectivity request and to compel the lower level controller (e.g.
MDSC) to select the path that Client/application controller has
chosen among the set of paths returned by the Path Computation
primitives. The importance of this primitives is for example in a
scenario like multi-domain in which the optimal path obtained by an
orchestrator as sum of optimal paths for different domain controller
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cannot be the optimal path in the Client/application controller
prospective. This only applies between CNC and MDSC.
2.1.6. VN Query
<VN Query> refers to any query pertaining to the VN that has been
already instantiated. VN Query fulfills a pull model and permit to
get topology view.
<VN Query Reply> refers to the reply in response to <VN Query>.
2.1.7. TE Update (for TE resources)
<TE Update> it is a primitives specifically related to MPI
interface to provide TE resource update between any domain
controller towards MDSC regarding the entire content of any "domain
controller" TE topology or an abstracted filtered view of TE
topology depending on negotiated policy.
<TE Update> ::= [<Abstraction>]<TE-topology...>
<TE-topology> ::= <TE-Topology-reference> <Node-list> <Link-list>
<Node-list> ::= <Node>[<Node-list>]
<Node> ::= <Node> <TE-Termination Points>
<Link-list> ::= <Link>[<Link-list>]
Where
<Abstraction> provides information on level of abstraction (as
determined a priori).
<TE-topology-reference> ::= information related to the specific te-
topology related to nodes and links present in this TE-topology.
<Node-list> ::= detailed information related to a specific node
belonging to a te-topology e.g. te-node-attributes [TE-TOPO].
<Link-list> ::= information related to the specific link related
belonging to a te-topology e.g. te-link-attributes [TE-TOPO].
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<TE-Termination Points> ::= information details associated to the
termination point of te-link related to a specific node e.g.
interface-switching-capability [TE-TOPO].
2.2. VN Objects
This section provides a list of objects associated to VN action
primitives.
2.2.1. VN Identifier
<VN Identifier> is a unique identifier of the VN.
2.2.2. VN Service Characteristics
VN Service Characteristics describes the customer/application
requirements against the VNs to be instantiated.
<VN Service Characteristics> ::= <VN Connectivity Type>
(<VN Traffic Matrix>...)
<VN Survivability>
Where
<VN Connectivity Type> ::= <P2P>|<P2MP>|<MP2MP>|<MP2P>|<Multi-
destination>
The Connectivity Type identifies the type of required VN Service. In
addition to the classical type of services (e.g. P2P/P2MP etc.),
ACTN defines the "multi-destination" service that is a new P2P
service where the end points are not fixed. They can be chosen among
a list of pre-configured end points or dynamically provided by the
CNC.
<VN Traffic Matrix> ::= <Bandwidth>
[<VN Constraints>]
The VN Traffic Matrix represents the traffic matrix parameters
required against the service connectivity required and so the VN
request instantiation between service related Access Points [ACTN-
Frame]. Bandwidth is a mandatory parameter and a number of optional
constrains can be specified in the <VN Constrains> (e.g. diversity,
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cost). They can include objective functions and TE metrics bounds as
specified in [RFC5441].
Further details on the VN constraints are specified below:
<VN Constraints> ::= [<Layer Protocol>]
[<Diversity>]
[<Shared Risk>]
<Metric>
Where:
<Layer Protocol> Identifies the layer at which the VN service is
requested. It could be for example MPLS, ODU, and OCh.
<Diversity> This allows asking for diversity constraints for a VN
Instantiate/Modify or a VN Path Compute. For example, a new VN or
a path is requested in total diversity from an existing one (e.g.
diversity exclusion).
<Diversity> ::= <VN-exclusion> (<VN-id>...) |
<VN-E2E Tunnel-exclusion> (<Tunnel-id>...)
<Shared Risk> Based on the realization of VN required, group of
physical resources can be impacted by the same risk. An E2E
tunnel can be impacted by this shared risk. This is used to get
the SRLG associated with the different tunnels composing a VN.
<Metric> can include all the Metrics (cost, delay, delay
variation, latency), bandwidth utilization parameters defined and
referenced by [RFC3630] and [RFC7471].
<VN Survivability> describes all attributes related to the VN
recovery level and its survivability policy enforced by the
customers/applications.
<VN Survivability> ::= <VN Recovery Level>
[<VN Tunnel Recovery Level>]
[<VN Survivability Policy>]
Where:
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<VN Recovery Level> It is a value representing the requested
level of resiliency required against the VN. The following
values are defined:
. Unprotected VN
. VN with per tunnel recovery: The recovery level is defined
against the tunnels composing the VN and it is specified in
the <VN Tunnel Recovery Level>.
<VN Tunnel Recovery Level> ::= <0:1>|<1+1>|<1:1>|<1:N>|<M:N>|
<On the fly restoration>
The VN Tunnel Recovery Level indicates the type of protection
or restoration mechanism applied to the VN. It augments the
recovery types defined in [RFC4427].
<VN Survivability Policy> ::= [<Local Reroute Allowed>]
[<Domain Preference>]
[<Push Allowed>]
[<Incremental Update>]
Where:
<Local Reroute Allowed> is a delegation policy to the Server
to allow or not a local reroute fix upon a failure of the
primary LSP.
<Domain Preference> is only applied on the MPI where the MDSC
(client) provides a domain preference to each PNC
(server).e.g. when a inter-domain link fails, then PNC can
choose the alternative peering with this info.
<Push Allowed> is a policy that allows a server to trigger an
updated VN topology upon failure without an explicit request
from the client. Push action can be set as default unless
otherwise specified.
<Incremental Update> is another policy that triggers an
incremental update from the server since the last period of
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update. Incremental update can be set as default unless
otherwise specified.
2.2.3. VN End-Point
<VN End-Point> Object describes the VN's customer end-point
characteristics.
<VN End-Point> ::= (<Access Point Identifier>
[<Access Link Capability>]
[<Source Indicator>])...
Where:
<Access point identifier> It represents a unique identifier of the
client end-point. They are used by the customer to ask for the
setup of a virtual network creation. A <VN End-Point> is defined
against each AP in the network and is shared between customer and
provider. Both the customer and the provider will map it against
his own physical resources.
<Access Link Capability> An optional object that identifies the
capabilities of the access link related to the given access point.
(e.g., max-bandwidth, bandwidth availability, etc.)
<Source Indicator> indicates if an End-point is source or not.
2.2.4. VN Objective Function
The VN Objective Function applies to each VN member (i.e., each E2E
tunnel) of a VN.
The VN Objective Function can reuse objective functions defined in
[RFC5541] section 4.
For a single path computation, the following objective functions are
defined:
o MCP is the Minimum Cost Path with respect to a specific
metric (e.g. shortest path).
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o MLP is the Minimum Load Path, that means find a path
composted by te-link least loaded.
o MBP is the Maximum residual Bandwidth Path.
For a concurrent path computation, the following objective functions
are defined:
o MBC is to Minimize aggregate Bandwidth Consumption.
o MLL is to Minimize the Load of the most loaded Link.
o MCC is to Minimize the Cumulative Cost of a set of paths.
2.2.5. VN Action Status
<VN Action Status> is the status indicator whether the VN has been
successfully instantiated, modified, or deleted in the server
network or not in response to a particular VN action.
Note that this action status object can be implicitly indicated and
thus not included in any of the VN primitives discussed in Section
2.3.
2.2.6. VN Associated LSP
<VN Associated LSP> describes the instantiated LSPs that is
associated with the VN. <VN Associated LSP> is used between each
domain PNC and the MDSC as part of VN Update once the VN is
instantiated in each domain network and when CNC want to have more
details about the topology instantiated as consequence of a VN
Instantiate.
<VN Associated LSP> ::= <VN Identifier> (<LSP>...)
2.2.7. VN Computed Path
The VN Computed Path is the list of paths obtained after the VN path
computation request from higher controller. Note that the computed
path is to be distinguished from the LSP. When the computed path is
signaled in the network (and thus the resource is reserved for that
path), it becomes an LSP.
<VN Computed Path> ::= (<Path>...)
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2.2.8. VN Service Preference
This section provides VN Service preference. VN Service is defined
in Section 2.
<VN Service Preference> ::= [<Location Service Preference >]
[<Client-specific Preference >]
[<End-Point Dynamic Selection Preference >]
Where
<Location Service Preference describes the End-Point Location's
(e.g. Data Centers) support for certain Virtual Network Functions
(VNFs) (e.g., security function, firewall capability, etc.)and is
used to find the path that satisfies the VNF constraint.
<Client-specific Preference> describes any preference related to
Virtual Network Service (VNS) that application/client can enforce
via CNC towards lower level controllers. For example, permission
the correct selection from the network of the destination related
to the indicated VNF It is e.g. the case of VM migration among
data center and CNC can enforce specific policy that can permit
MDSC/PNC to calculate the correct path for the connectivity
supporting the data center interconnection required by
application.
<End-Point Dynamic Selection Preference> describes if the End-
Point (e.g. Data Center) can support load balancing, disaster
recovery or VM migration and so can be part of the selection by
MDSC following service Preference enforcement by CNC.
2.3. Mapping of VN Primitives with VN Objects
This section describes the mapping of VN Primitives with VN Objects
based on Section 2.2.
<VN Instantiate> ::= <VN Service Characteristics>
<VN Objective Function>
<VN End-Point>
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[<VN Service Preference>]
<VN Modify> ::= <VN identifier>
<VN Service Characteristics>
[<VN Objective Function>]
<VN End-Point>
[<VN Service Preference>]
<VN Delete> ::= <VN Identifier>
<VN Update> :: = <VN Identifier>
<VN Associated LSP>
<VN Path Compute Request> ::= <VN Service Characteristic>
<VN Objective Function>
<VN End-Point>
<VN Path Compute Reply> ::= <VN Computed Path>
<VN Query> ::= <VN Identifier>
<VN Query Reply> ::= <VN Identifier>
<VN Associated LSP>
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3. References
3.1. Normative References
[DRAFT-SER-AWARE] Dhruv Dhody, Qin Wu, Vishwas Manral, Zafar Ali,
and Kenji Kumaki, "Extensions to the Path Computation
Element Communication Protocol (PCEP) to compute service
aware Label Switched Path (LSP).," June 2016, draft-ietf-
pce-pcep-service-aware-10.
3.2. Informative References
[TE-TOPO] Liu, X. et al., "YANG Data Model for TE Topologies",
draft-ietf-teas-yang-te-topo, work in progress.Informative
References
[ACTN-Req] Y. Lee, et al., "Requirements for Abstraction and Control
of Transport Networks", draft-lee-teas-actn-requirements,
work in progress.
[ACTN-Frame] D. Ceccarelli, et al., "Framework for Abstraction and
Control of Transport Networks", draft-ceccarelli-teas-
actn-framework, work in progress.
[Stateful-PCE] E. Crabbe, et al., "PCEP Extensions for Stateful
PCE", draft-ietf-pce-stateful-pce, work in progress.
[RFC5541] JL. Le Roux, JP. Vasseur and Y. Lee, "Encoding of Objective Functions
in the Path Computation Element Communication Protocol (PCEP)", RFC
5541, June 2009.
[RFC7926] A.Farrel, et al., "Problem Statement and Architecture for
Information Exchange between Interconnected Traffic-
Engineered Networks", RFC 7926, July 2016.
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4. Contributors
Contributors' Addresses
Authors' Addresses
Young Lee (Editor)
Huawei Technologies
5340 Legacy Drive
Plano, TX 75023, USA
Phone: (469)277-5838
Email: leeyoung@huawei.com
Sergio Belotti (Editor)
Alcatel Lucent
Via Trento, 30
Vimercate, Italy
Email: sergio.belotti@alcatel-lucent.com
Dhruv Dhody
Huawei Technologies,
Divyashree Technopark, Whitefield
Bangalore, India
Email: dhruv.ietf@gmail.com
Daniele Ceccarelli
Ericsson
Torshamnsgatan,48
Stockholm, Sweden
Email: daniele.ceccarelli@ericsson.com
Bin Young Yun
ETRI
Email: byyun@etri.re.kr
Haomian Zheng
Huawei Technologies
Email: zhenghaomian@huawei.com
Xian Zhang
Huawei Technologies
Email: zhang.xian@huawei.com
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Appendix A: ACTN Applications
A.1. Coordination of Multi-destination Service Requirement/Policy
+----------------+
| CNC |
| (Global DC |
| Operation |
| Control) |
+--------+-------+
| | Service Requirement/Policy:
| | - Endpoint/DC location info
| | - Endpoint/DC dynamic
| | selection policy
| | (for VM migration, DR, LB)
| v
+---------+---------+
| Multi-domain | Service policy-driven
|Service Coordinator| dynamic DC selection
+-----+---+---+-----+
| | |
| | |
+----------------+ | +----------------+
| | |
+-----+-----+ +-----+------+ +------+-----+
| PNC for | | PNC for | | PNC for |
| Transport | | Transport | | Transport |
| Network A | | Network B | | network C |
+-----------+ +------------+ +------------+
| | |
+---+ ------ ------ ------ +---+
|DC1|--//// \\\\ //// \\\\ //// \\\\---+DC5|
+---+ | | | | | | +---+
| TN A +-----+ TN B +----+ TN C |
/ | | | | |
/ \\\\ //// / \\\\ //// \\\\ ////
+---+ ------ / ------ \ ------ \
|DC2| / \ \+---+
+---+ / \ |DC6|
+---+ \ +---+ +---+
|DC3| \|DC4|
+---+ +---+
DR: Disaster Recovery
LB: Load Balancing
Figure A.1: Service Policy-driven Data Center Selection
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Figure A.1 shows how VN service policies from the CNC are
incorporated by the MDSC to support multi-destination applications.
Multi-destination applications refer to applications in which the
selection of the destination of a network path for a given source
needs to be decided dynamically to support such applications.
Data Center selection problems arise for VM mobility, disaster
recovery and load balancing cases. VN's service policy plays an
important role for virtual network operation. Service policy can be
static or dynamic. Dynamic service policy for data center selection
may be placed as a result of utilization of data center resources
supporting VNs. The MDSC would then incorporate this information to
meet the service objective of this application.
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A.2. Application Service Policy-aware Network Operation
+----------------+
| CNC |
| (Global DC |
| Operation |
| Control) |
+--------+-------+
| | Application Service Policy
| | - VNF requirement (e.g.
| | security function, etc.)
| | - Location profile for each VNF
| v
+---------+---------+
| Multi-domain | Dynamically select the
|Service Coordinator| network destination to
+-----+---+---+-----+ meet VNF requirement.
| | |
| | |
+---------------+ | +----------------+
| | |
+------+-----+ +-----+------+ +------+-----+
| PNC for | | PNC for | | PNC for |
| Transport | | Transport | | Transport |
| Network A | | Network B | | network C |
| | | | | |
+------------+ +------------+ +------------+
| | |
{VNF b} | | | {VNF b,c}
+---+ ------ ------ ------ +---+
|DC1|--//// \\\\ //// \\\\ //// \\\\-|DC5|
+---+ | | | | | |+---+
| TN A +---+ TN B +--+ TN C |
/ | | | | |
/ \\\\ //// / \\\\ //// \\\\ ////
+---+ ------ / ------ \ ------ \
|DC2| / \ \\+---+
+---+ / \ |DC6|
{VNF a} +---+ +---+ +---+
|DC3| |DC4| {VNF a,b,c}
+---+ +---+
{VNF a, b} {VNF a, c}
Figure A.2: Application Service Policy-aware Network Operation
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This scenario is similar to the previous case in that the VN service
policy for the application can be met by a set of multiple
destinations that provide the required virtual network functions
(VNF). Virtual network functions can be, for example, security
functions required by the VN application. The VN service policy by
the CNC would indicate the locations of a certain VNF that can be
fulfilled. This policy information is critical in finding the
optimal network path subject to this constraint. As VNFs can be
dynamically moved across different DCs, this policy should be
dynamically enforced from the CNC to the MDSC and the PNCs.
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A.3. Network Function Virtualization Service Enabled Connectivity
+----------------+
| CNC |
| (Global DC |
| Operation |
| Control) |
+--------+-------+
| | Service Policy related to VNF
| | (e.g., firewall, traffic
| | optimizer)
| |
| v
+---------+---------+
| Multi-domain | Select network
|Service Coordinator| connectivity subject to
+-----+---+---+-----+ meeting service policy
| | |
| | |
+---------------+ | +----------------+
| | |
+------+-----+ +-----+------+ +------+-----+
| PNC for | | PNC for | | PNC for |
| Transport | | Transport | | Transport |
| Network A | | Network B | | network C |
| | | | | |
+------------+ +------------+ +------------+
| | |
| | |
+---+ ------ ------ ------ +---+
|DC1|--//// \\\\ //// \\\\ //// \\\\-|DC5|
+---+ | | | | | |+---+
| TN A +---+ TN B +--+ TN C |
/ | | | | |
/ \\\\ //// / \\\\ //// \\\\ ////
+---+ ------ / ------ \ ------ \
|DC2| / \ \\+---+
+---+ / \ |DC6|
+---+ +---+ +---+
|DC3| |DC4|
+---+ +---+
Figure A.3: Network Function Virtualization Service Enabled
Connectivity
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Network Function Virtualization Services are usually setup between
customers' premises and service provider premises and are provided
mostly by cloud providers or content delivery providers. The context
may include, but not limited to a security function like firewall, a
traffic optimizer, the provisioning of storage or computation
capacity where the customer does not care whether the service is
implemented in a given data center or another. The customer has to
provide (and CNC is providing this)the type of VNF he needs and the
policy associated with it (e.g. metric like estimated delay to reach
where VNF is located in the DC). The policy linked to VNF is
requested as part of the VN instantiation. These services may be
hosted virtually by the provider or physically part of the network.
This allows the service provider to hide his own resources (both
network and data centers) and divert customer requests where most
suitable. This is also known as "end points mobility" case and
introduces new concepts of traffic and service provisioning and
resiliency (e.g., Virtual Machine mobility).
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A.4. Dynamic Service Control Policy Enforcement for Performance and
Fault Management
+------------------------------------------------+
| Customer Network Controller |
+------------------------------------------------+
1.Traffic| /|\4.Traffic | /|\
Monitor& | | Monitor | | 8.Traffic
Optimize | | Result 5.Service | | modify &
Policy | | modify& | | optimize
\|/ | optimize Req.\|/ | result
+------------------------------------------------+
| Multi-domain Service Coordinator |
+------------------------------------------------+
2. Path | /|\3.Traffic | /|\
Monitor | | Monitor | |7.Path
Request | | Result 6.Path | | modify &
| | modify& | | optimize
\|/ | optimize Req.\|/ | result
+------------------------------------------------+
| Physical Network Controller |
+------------------------------------------------+
Figure A.4: Dynamic Service Control for Performance and Fault
Management
Figure A.4 shows the flow of dynamic service control policy
enforcement for performance and fault management initiated by
customer per VN. The feedback loop and filtering mechanism tailored
for VNs performed by the MDSC differentiates this ACTN scope from
traditional network management paradigm. VN level dynamic OAM data
model is a building block to support this capability.
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A.5. E2E VN Survivability and Multi-Layer (Packet-Optical) Coordination
for Protection/Restoration
+----------------+
| Customer |
| Network |
| Controller |
+--------*-------+
* | E2E VN Survivability Req.
* | - VN Protection/Restoration
* v - 1+1, Restoration, etc.
+------*-----+ - End Point (EP) info.
| |
| MDSC | MDSC enforces VN survivability
| | requirement, determining the
| | optimal combination of Packet/
+------*-----+ Optical protection/restoration
* Optical bypass, etc.
*
*
**********************************************
* * * *
+----*-----+ +----*----+ +----*-----+ +----*----+
|PNC for | |PNC for | |PNC for | |PNC for |
|Access N. | |Packet C.| |Optical C.| |Access N.|
+----*-----+ +----*----+ +----*-----+ +---*-----+
* --*--- * *
* /// \\\ * *
--*--- | Packet | * ----*-
/// \\\ | Core +------+------/// \\\
| Access +----\\ /// * | Access |
| Network | ---+-- * | Network | +---+
|\\\ /// | * \\\ ///---+EP6|
| +---+- | | -----* -+---+ +---+
+-+-+ | | +----/// \\\ | |
|EP1| | +--------------+ Optical | | | +---+
+---+ | | Core +------+ +--+EP5|
+-+-+ \\\ /// +---+
|EP2| ------ |
+---+ | |
+--++ ++--+
|EP3| |EP4|
+---+ +---+
Figure A.5: E2E VN Survivability and Multi-layer Coordination for
Protection and Restoration
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Figure A.5 shows the need for E2E protection/restoration control
coordination that involves CNC, MDSC and PNCs to meet the VN
survivability requirement. VN survivability requirement and its
policy need to be translated into multi-domain and multi-layer
network protection and restoration scenarios across different
controller types. After an E2E path is setup successfully, the MDSC
has a unique role to enforce policy-based flexible VN survivability
requirement by coordinating all PNC domains.
As seen in Figure A.5, multi-layer (i.e., packet/optical)
coordination is a subset of this E2E protection/restoration control
operation. The MDSC has a role to play in determining an optimal
protection/restoration level based on the customer's VN
survivability requirement. For instance, the MDSC needs to interface
the PNC for packet core as well as the PNC for optical core and
enforce protection/restoration policy as part of the E2E
protection/restoration. Neither the PNC for packet core nor the PNC
for optical core is in a position to be aware of the E2E path and
its protection/restoration situation. This role of the MDSC is
unique for this reason. In some cases, the MDSC will have to
determine and enforce optical bypass to find a feasible reroute path
upon packet core network failure which cannot be resolved the packet
core network itself.
To coordinate this operation, the PNCs will need to update its
domain level abstract topology upon resource changes due to a
network failure or other factors. The MDSC will incorporate all
these update to determine if an alternative E2E reroute path is
necessary or not based on the changes reported from the PNCs. It
will need to update the E2E abstract topology and the affected CN's
VN topology in real-time. This refers to dynamic synchronization of
topology from Physical topology to abstract topology to VN topology.
MDSC will also need to perform the path restoration signaling to the
affected PNCs whenever necessary.
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