Teas Working Group Young Lee
Internet Draft Huawei
Intended status: Informational Sergio Belotti
Alcatel-Lucent
Expires: April 2016
Dhruv Dhody
Huawei
Daniele Ceccarelli
Ericsson
Bin Young Yun
ETRI
October 5, 2015
Information Model for Abstraction and Control of TE Networks (ACTN)
draft-leebelotti-teas-actn-info-01.txt
Abstract
This draft provides an information model for abstraction and control
of Traffic Engineered (TE) networks (ACTN).
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Table of Contents
1. Introduction...................................................3
2. ACTN Common Interfaces Information Model.......................4
2.1. VN Action Primitives......................................5
2.1.1. VN Instantiate.......................................5
2.1.2. VN Modify............................................6
2.1.3. VN Delete............................................6
2.1.4. VN Path Compute......................................6
2.1.5. VN Query.............................................6
2.1.6. VN Update............................................6
2.2. VN Objects................................................7
2.2.1. VN Identifier........................................7
2.2.2. VN Topology Metric...................................7
2.2.3. Traffic Matrix.......................................8
2.2.4. VN Survivability.....................................9
2.2.5. VN Status...........................................10
2.2.6. VN Topology.........................................10
2.2.7. VN Connectivity Topology............................10
2.2.8. VN Service Policy...................................10
3. References....................................................11
3.1. Informative References...................................11
4. Contributors..................................................12
Contributors' Addresses..........................................12
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Authors' Addresses...............................................12
Appendix A: ACTN Applications....................................13
A.1. Coordination of Multi-destination Service
Requirement/Policy.........................................13
A.2. Application Service Policy-aware Network Operation....15
A.3. Network Function Virtualization Service Enabled
Connectivity...............................................17
A.4. Dynamic Service Control Policy Enforcement for
Performance and Fault Management...........................19
A.5. E2E VN Survivability and Multi-Layer (Packet-Optical)
Coordination for Protection/Restoration....................20
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).
+-------+ +-------+ +-------+
| CNC-A | | CNC-B | | CNC-C |
+-------+ +-------+ +-------+
\___________ | ____________ _/
---------- | CMI ------------
\ | /
+-----------------------+
| MDSC |
+-----------------------+
_________/ | \_________
-------- | MPI ------------____
/ | \
+-------+ +-------+ +-------+
| PNC | | PNC | | PNC |
+-------+ +-------+ +-------+
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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].
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.
At a minimum, the following VN action primitives should be
supported:
- VN Instantiate (See Section 2.1.1. for the description)
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- VN Modify (See Section 2.1.2. for the description)
- VN Delete (See Section 2.1.3. for the description)
- VN Query (See Section 2.1.4. for the description)
- VN Path Compute (See Section 2.1.4. for the description)
- VN Update ((See Section 2.1.5. for the description)
The functionality below will be supported as part of already defined
primitives as above.
- Security negotiation
- Local Domain path computation (related to PNC
- Coordination of multi-destination (<Coordination
Multidestination>)
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) instantiate; (ii) modify; (iii) delete;
(iv) path compute; (v) query; (vi) update.
<VN Action> ::= <VN Instantiate> |
<VN Modify> |
<VN Delete> |
<VN Path Compute> |
<VN Query> |
<VN Update>
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.
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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.
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 Path Compute
<VN Path Compute> 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.
This is to be differentiated from a VN Instantiate. The purpose of
VN Path Compute is a priori exploration to estimate network
resources availability before making a VN instantiate decision.
Obviously an abstracted view of network resources topology is needed
to permit this function. This action is also necessary for an MDSC
to PNCs in determining end-to-end multi-domain paths. VN Instantiate
may also trigger an MDSC for a VN Path Compute to lower-level PNCs
in order to determine end-to-end paths that comprise of a VN.
2.1.5. 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.
2.1.6. 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.
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There are other existing and upcoming TE mechanisms to fulfill the
same function as VN Update. VN Update can be built on these other
existing TE mechanisms. The details are TDB.
[Editor's Note: The mapping of VN Primitives and their VN Objects will
be provided in the future revision.]
2.2. VN Objects
This section provides a list of objects associated with VN action
primitives.
2.2.1. VN Identifier
<VN Identifier> is an identifier that identifies a unique VN.
2.2.2. VN Topology Metric
<VN Topology Metric> describes the requirements/preferences of VNs
that customers/applications want to instantiate.
<VN Topology Metric> ::= <VN Topology Type>
<VN Topology Attributes>
[<VN Topology Preference>]
[<VN Topology Objective Function>]
Where
<VN Topology Type> ::= <Path Vector> | <Graph>
<VN Topology Attributes describes characteristics associated
with any VN Topology link/path. These attributes could be
reservable bandwidth, maximum link/path capacity, latency,
SRLG, etc.
<VN Topology Preference> describes if the request is
. a single vs. a bulk request,
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. Multiple VN diversity in case of a bulk request, whether
VNs should be disjoint or not),
. Single VN diversity (node/link disjoint)
. Others TBD.
<VN Topology Objective Function> indicates a higher level of
objective function applied to the VN level, for computing a
path vector.VN is comprised of a set of paths and each one of
these needs an objective function.
2.2.3. Traffic Matrix
<Traffic Matrix> describes connectivity-level attributes that need
to be conveyed by the CNC to MDSC or the MDSC to PNCs.
<Traffic Matrix> ::= <End-Point List>
<Connectivity Type>
<Connectivity Metric>
Where
<End-Point List> ::= (<Interface Identifier>
[<Client Interface Capability>]
[<Source Indicator>])...
It is assumed that a list of interface identifiers has been known
to the server prior to any VN actions. The Client Capability
comprises the client interface capability (e.g., maximum
interface bandwidth, etc.).
<Source Indicator> indicates if an End-point is source or not.
<Connectivity Type> ::= <P2P> | <P2MP> | <MP2MP> | <MP2P>
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<Multi-destination>
<Connectivity Metric> ::= <Bandwidth>
[<Latency>]
[<Latency-Variation>]
[<Packet-Loss>]
2.2.4. VN Survivability
<VN Survivability> describes all attributes related with the VN
protection level and its survivability policy enforced by the
customers/applications.
<VN Survivability> ::= <VN Protection Level>
<VN Survivability Policy>
Where
<VN Protection Level> ::= <No Protection> | <1+1> | <1:N>
<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).
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<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
update. Incremental update can be set as default unless
otherwise specified.
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.
2.2.6. VN Topology
<VN Topology> describes VN topology. Details of <VN Topology> are
TBD.
VN Topology can be defined using existing TE mechanisms. Details are
TBD.
2.2.7. VN Connectivity Topology
<VN Connectivity Topology> describes the instantiated VN property.
Details are TBD.
[Editor's Note: This may be combined with <VN Topology>.]
2.2.8. VN Service Preference
<VN Service Preference> ::= <Location Service Preference >
<Client-specific Preference >
<End-Point Dynamic Selection Preference >
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Where
<Location Service Preference> describes the End-Point Location's
support for certain Virtual Network Functions (VNFs) (e.g.,
security function, firewall capability, etc.).
<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 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.
3. References
3.1. 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.
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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 Dhoddy
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.
Lee-Belotti Expires April 5, 2016 [Page 21]