The Architecture for Application-based Policy On Network Functions
draft-zhou-aponf-architecture-01
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| Authors | Cathy Zhou , Tina Tsou (Ting ZOU) , Diego R. Lopez , Georgios Karagiannis , Qiong Sun | ||
| Last updated | 2014-07-02 | ||
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draft-zhou-aponf-architecture-01
Network Working Group C. Zhou
Internet-Draft T. Tsou
Intended status: Informational Huawei Technologies
Expires: January 3, 2015 D. Lopez
Telefonica
G. Karagiannis
University of Twente
Q. Sun
China Telecom
July 2, 2014
The Architecture for Application-based Policy On Network Functions
draft-zhou-aponf-architecture-01
Abstract
Currently, there are network management applications that present
specific demands on a communication network. This document describes
the APONF basic architecture, its elements and interfaces. The main
APONF architecture entities are the Network Management Application
Agent (NMAA), which is a network entity that creates and runs network
services, and Application-based Policy Decision (ABPD), which
supports classified application models. Each of these models support
application demands that are similar in nature and therefore can be
grouped/classified together. Moreover, the ABPD maps the classified
application models into network capabilities, e.g., network
management and traffic policies.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 3, 2015.
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Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Overview of the APONF Architecture . . . . . . . . . . . . . 4
4. Network Management Applications . . . . . . . . . . . . . . . 6
4.1. Network Management Application Agent (NMAA) . . . . . . . 7
5. Application Based Policy Decision . . . . . . . . . . . . . . 9
6. Network Elements . . . . . . . . . . . . . . . . . . . . . . 12
7. The APONF Interface . . . . . . . . . . . . . . . . . . . . . 12
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13
11. informative References . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
As the Internet grows, more and more new services keep on arising,
and network traffic is rapidly increased, which may result in slow
performance of network devices (e.g., BRAS) and poor end-user
experience. In addition, especially for cloud applications, the
cloud tenants and developers usually need to use the communication
network capabilities, such as dynamic network management and dynamic
traffic steering, easily, accurately and efficiently. In this way,
the deployment of new applications and services may be accelerated
and the user experience can be improved.
In particular, today network operators are challenged to create an
abstract view of their network infrastructure and help service
developers on using and programming this abstraction rather than
manipulating individual devices. In this context, network management
applications can be used to provide the required configuration and
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application programming interfaces to such service developers.
Subsequently, a network management application can use the
application based demands and possibly update its associated network
configuration and/or network topology model. Examples of network
management applications that can modify the network configuration
and/or network topology models are for example, Distributed Data
Center Application and IPv6 transitions, need to change the network
infrastructure configuration.
The up to date network configuration and network topology model needs
to (1) be communicated to e.g., the network management and
controlling systems, (2) map the network configuration and network
topology models into specific network management policies, i.e.,
device level configuration models.
Currently, there are no IETF standard mechanisms or modeling
languages that can directly be applied to model the network
configuration nor the network topology. IETF has however, created
the IETF SFC WG [SFC] to document a new approach to service delivery
and operation, where one of its goals is to realize an abstract view
of a network by using a service graph instance denoted as the Service
Function Path (SFP). This will enable the development of suitable
models for network configuration and network topology.
The main goal of this document is to specify the APONF basic
architecture, its elements and interfaces. The main APONF
architecture entities are the Network Management Application Agent
(NMAA) and the Application-based Policy Decision (ABPD). NMAA is a
network entity that creates and runs network services and is able to
use the application based demands and possibly update their
associated SPF based network configuration and/or network topology
model. The ABPD is able to map the SFP based network configuration
and network topology models into specific network management
policies, i.e., device level configuration models. The definition of
these network management policies is out of the APONF scope.
2. Terminology
AECON (Application Enabled Collaborative Network): The main goal of
the AECON activity (currently BOF) is to allow applications to
explicitly signal their flow characteristics to the network.
Device level configuration model: supports the description of the
network management policies and it describes the configuration
details at the device level.
Network Management Application: Network management are Operational
Support System (OSS) like applications that help a communication
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service provider to monitor, control, analyze and manage a
communication network.
Network configuration model: provides a declarative configuration of
the network.
Network topology model: describes the topology of a multi-layer
network.
NFVcon (Network Functions Virtualization configuration): The main
goal of this activity (BOF status) is to support the dynamic
configuration of NFV instances.
Service Function Chain (SFC): A service Function chain defines an
ordered set of service functions that must be applied to packets and/
or layer-2 frames selected as a result of classification. The
implied order may not be a linear progression as nodes may copy to
more than one branch. The term service chain is often used as
shorthand for service function chain.
Service Function Path (SFP): The instantiation of a service function
chain in the network. Packets follow a service function path from a
classifier through the required instances of service functions in the
network.
VNF (Virtualized Network Function): An implementation of an
executable software program that constitutes the whole or a part of
an NF and can be deployed on a virtualization infrastructure.
3. Overview of the APONF Architecture
This section depicts an overview of the architecture of application-
based policy on network functions. Figure 1 shows APONF
architecture. The basic components of the APONF architecture are:
Network Management Application: Operational Support System (OSS) like
applications that help a communication service provider to monitor,
control, analyze and manage a communication network. Several network
management applications MAY communicate with the Application Based
Policy Decision block via the Network Management Application Agent.
The Network Management Application Agent (NMAA):The NMAA is part of
the network management application and is a network entity that
creates and runs network services. These network services should be
developed by an operator, which are assumed to be already available.
The NMAA is able to generate for each of these network services and
using application based demands a SFP based network configuration and
network topology model.
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Application Based Policy Decision(ABPD): A network entity which
provides an interface to NMAA(s) and is able to map the classified
application based models, which are including the classified
application based demands and the SFP based network configuration and
network topology models, into specific network management policies,
i.e., device level configuration models, which are used by the
communication network. ABPD can communicate with multiple NMAAs
simultaneously.
Network Element (NE):handles incoming packets based on the ABDP
network management policies and the corresponding network management
and manipulation procedures.
Figure 1 shows the basic architecture of application-based policy on
network functions.
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+----------------------------------+ +----------------------------------+
| Network Management Application | | Network Management Application |
| | | |
| | | |
| +---------------------+ | | +---------------------+ |
| | Network Management | | | | Network Management | |
| | Application Agent | |... | | Application Agent | |
| | | | | | | |
| | (NMAA) | | | | (NMAA) | |
| +-------------+-------+ | | +---------+-----------+ |
| | | | | |
| | | | | |
+-----------------|----------------+ +------------------|---------------+
| |
| |
| |
+---------------|----------------------------------------|---------------+
|+--------------v--------------+ +---+ +-------------v--------------+|
||Classified Application Model | |...| |Classified Application Model||
|+-----------------------------+ +---+ +----------------------------+|
| |
| Application Based Policy Decision (ABPD) |
+-----------------------------------^------------------------------------+
|
|
|
+--------------------+---------------------+
| |
| |
| |
+----------------v---------------+ +----------------v-------------+
| | | |
| | ... | |
| Network Element | | Network Element |
+--------------------------------+ +------------------------------+
Figure 1: Architecture of application-based policy on network
functions
4. Network Management Applications
This architecture is expected to be used for several categories of
network management applications. Such network management
applications are representing the realizations of the APONF use
cases, which are: "Distributed Data Center " [ID.cheng-aponf-ddc-use-
cases], "IPv6 transition " [ID.sun-aponf-openv6-use-cases],
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"Virtualized Enterprise Applications " [ID.huang-aponf-use-cases-
label], "Source Address Validation and Traceback (SAVI)" [SAVI]
[ID.bi-aponf-sdsavi], and "Using the abstract view of network by
service developers" [ID.saldana-aponf-abstract-network-view-use-
case].
These network management applications are represented by a set of
network services. Each network service can be represented by a
classified application based policy model, since it can model the
group of demands coming from a bundle of applications that impose
similar requirements on the communication network. Such network
services can be "Distributed Data Center ", " IPv6 transition ",
"Virtualized Enterprise Applications " and "Source Address Validation
and Traceback (SAVI) " and "Using the abstract view of network by
service developers".
4.1. Network Management Application Agent (NMAA)
The NMAA is part of the network management application and is a
network entity that creates and runs network services. These network
services should be developed by an operator, which are assumed to be
already available.
The assumption here is that the network management application has a
complete view of the available network and network capabilities that
it can use. Moreover, it is assumed that the network management
application is able to have the abstract view of the network and on
how the network service is mapped into this abstract view. This
network abstract view is defined using the Service Function Path
(SFP), specified in the IETF SFC WG. It is assumed that the NMAA can
use the network service description and create a SFP based network
configuration and network topology model, by using the guidelines
provided by the SFC WG.
An NMAA is a typical OSS gateway or Network Management Station
entity, that needs to support the following new functional blocks as
shown in Figure 2:
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+----------------------------------------------+
|NMAA |
| |
| +--------------+ +--------------+ |
| | | | Create/Update| |
| | Typical OSS | | SFP | |
| | | | | |
| +--------------+ +--------------+ |
| |
| |
| |
| +--------------+ +--------------+ |
| | End User | | NSIS | |
| | Application | | | |
| | Interaction | | Interface | |
| +--------------+ +--------------+ |
+----------------------------------------------+
Figure 2: NMAA Functionality Block Diagram
o Typical OSS (Operations Support System) features.
o Create/Update SFPs: this is a NMAA functional block and is used by
the NMAA to use the network service and create or update an SFP.
The assumption used here is that the description of the network
services is provided to end user applications in such a way that
the end user application developer can use and program certain
network capabilities in such a way that the end user application
can increase its support for end user QoE. The modified versions
of the network service are made known to the network management
application and NMAA. This event initiates the update of the SFP.
o End User Application Interaction: this functional block is used to
provide and receive information to/from the end user application
engine. This functional block is in charge to provide the
description of the network services to end user applications in
such a way that the end user application developer can use and
program certain network capabilities in such a way that the end
user application can increase its support for end user QoE. This
functional block is also used to receive the modified versions of
the network service from the end user application and to inform
the Create/Update SFPs functional block about this change. This
event initiates the update of the SFP.Note that it is assumed that
the realization of this functional block and the interface with
the end user are out of the APONF's scope.
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o NMAA NSIS (Next Steps in Signaling) interface: this functional
Block is used to support the enhanced APONF NSIS protocol engine
as described in Section 7.
The Network Management Application Agent (NMAA) will use the APONF
interface to communicate with the Application Based Policy Decision
(ABPD) entity.
5. Application Based Policy Decision
The Application-Based Policy Decision (ABPD) block, is a an entity
used between the Network Management Applications and the network
elements to provide and maintain the application based policies. It
supports the APONF interface/protocol and is a software repository,
which stores the information associated with each NE, and maps the
classified application models, i.e., application based demands and
the SPF based network configuration and network topology models, into
existing network management policies, i.e., device configuration
models. In particular, by creating application based policies that
mirror application semantics, a better mapping to existing network
management policies can be realized. This provides a simple, self-
documenting mechanism for capturing application-based policy
requirements and mapping them to existing network management
policies. This will allow applications to use the network
capabilities in a more accurate and efficient way.
Figure 3 illustrates the ABPD functionality block diagram, which is
based on [ID.farrkingel-pce-abno-architecture] and enhanced to
satisfy the demands of the APONF use cases.
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+----------------------------------------------------------------+
|ABPD Block |
| +--------------------------+ |
| | ABPD Management Interface| |
| +------------+-------------+ |
| +--------------+ | +--------------++--------------+ |
| | ABPD NSIS | | | Fresh SFP ||Application to| |
| | | | | || Network | |
| | Interface | | | Maintenance || Mapping | |
| +-----------+--+ | +------+-------++-+------------+ |
| | | | | |
| | | | | |
| +-+----+------+------------+-+ |
| +------+ | | +-------+ |
| |Policy+--+ ABPD Controller +-----+ | |
| |Agent | | +--+ | OAM | |
| +-+--+-+ +-+------------+----------+--+ | |Handler| |
| | | | | | | | | |
| +-----++ | +----+-+ +-------+-------+ | | +-------+ |
| |ALTO | +-+ VNTM |--+ | | | |
| |Server| +--+-+-+ | | | +---+--------+ |
| +--+---+ | | | PCE | | |I2RS client | |
| | +-------+ | | | | | | |
| | | | | | | +------------+ |
| +------+--+-+ | | | | |
| | Databases +-------:----+ | | |
| | TED | | +-+---+----+----+ | |
| | LSP-DB + | | | | | |
| +-----+--+--+ +-+---------------+-------+-+ |
| | Provisioning Manager | |
| +---------------------------+ |
+----------------------------------------------------------------+
Figure 3: ABPD Functionality Block Diagram
The Application Based Policy Decision (ABPD) block includes all the
functional blocks provided in Figure 1 of
[ID.farrkingel-pce-abno-architecture], together with the following
new defined functional blocks:
o Fresh SFPs Maintenance: maintains a fresh abstract view of the
network. Note that this is realized using the Service Function
Path (SFP), specified in the IETF SFC WG. Important to note is
that for each network service / classified application model that
is managed by a network management application a different SFP is
needed. So in order to support this the APONF architecture needs
to support a functional block that stores all these abstract views
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of the network in different SFPs that are identified by an unique
ID.
o Application to Network Mapping: the following features are
supported by this functional block:
o
1. Translates the actions and the changed SFP received from the
network management application, see explanation below, to a
new SFP. This is accomplished by using application based
demands generated by network management applications systems
to map the SFP based network configuration and network
topology models into specific network management policies,
i.e., into device level configuration models. Such
application based demands are:
2.
Encapsulating, de-encapsulating packets associated with a
flow into a tunnel (for example, VPN service, IPv6
transition service demands on the network).
Blocking, or dropping packets associated with a flow in
(the edge of) the network element when the network security
service is aware of the attack (for example, SAVI service,
Anti-DoS service demands on the network).
Configure and dynamically reconfigure data centers to the
steer and reroute traffic associated with a specific flow.
Configure and dynamically reconfigure data centers to
change priorities of different types of traffic associated
with a specific flow.
logging the traffic associated with a flow for network
security service, optimization of the traffic based on the
IETF ALTO [ID.ietf-alto-protocol].
Other actions defined by the administrator.
3. if required updates all databases, see Section 2.3.1.8 of
[ID.farrkingel-pce-abno-architecture].
4. Uses existing network management and signaling protocols, i2rs
[I2RS], SFC [SFC], NETCONF [NETCONF], NFVcon, etc., to request
the implementation of the changes into the network.
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o ABPD Network Management Interface: this functional block provides
the interface with existing network management, i2rs, SFC,
NETCONF, NFVcon, etc. protocols to request and negotiate the
implementation of the changes into the network configuration.
o ABPD NSIS (Next Steps in Signaling) interface: this functional
Block is used to support the enhanced APONF NSIS protocol engine.
The definition of the network management policies is out of the APONF
scope.
These application-based policy models can meet the application's
demands on the communication network and map these demands to network
management policies that can be understood by the communication
network.
6. Network Elements
The Network Element (NE) handles incoming packets based on the policy
information communicated with the ABPD block and makes corresponding
policy enforcement, which is based on existing network management
policies, see Section 5.
A NE may be a physical entity or a virtual entity and is locally
managed, whether via CLI, SNMP, or NeTConf. Examples of NEs can
include:
o A router that has an extended function module. The extended
module handles incoming packets basing on the flow table of the
module.
o A server that runs vRouter or vSwitch.
o A CGN that runs NAT, Tunnel En/De-capsulation functions.
o A virtual network function entity.
7. The APONF Interface
This APONF Interface/Protocol, needs to be specified by the APONF
effort and is used to support the communication between the NMAA
entity and the ABPD entity. The IETF Next Steps in Signaling (NSIS)
protocol may be extended in two ways to support this interface, see
[ID.karagiannis-aponf-problem-statement]:
1. Extend NSIS GIST [RFC5971] in such a way that it can be used for
off-path support;
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2. Specify a new signaling protocol (NSIS Signaling Layer Protocol),
similar to the NAT/Firewall NSLP [RFC5973] that can be applied
and support the APONF use cases. This signaling protocol is
denoted as APONF NSLP.
8. Security Considerations
Security is a key aspect of any protocol that allows state
installation and extracting of detailed configuration states. More
investigation remains to fully define the security requirements, such
as authorization and authentication levels.
9. IANA Considerations
No IANA considerations.
10. Acknowledgements
The authors of this draft would like to thank the following persons
for the provided valuable feedback: Jose Saldana, Spencer Dawkins,
Jun Bi, Xing Li, Chongfeng Xie, Benoit Claise, Ian Farrer, Marc
Blancet, Zhen Cao, Hosnieh Rafiee, Mehmet Ersue, Mohamed Boucadair.
11. informative References
[ID.farrkingel-pce-abno-architecture]
King, D. and A. Farrel, "A PCE-based Architecture for
Application-based Network Operations", Feb 2014.
[ID.karagiannis-aponf-problem-statement]
Karagiannis, G., Liu, W., Tsou, T., Sun, Q., and D. Lopez,
"Problem Statement for Application Policy on Network
Functions (APONF)(work in progress)", June 2014.
[ID.montpetit-transport-use-cases]
Montpetit, M. and I. Zhovnirovsky, "Use Cases and
Requirements", Feb 2014.
[RFC5971] Schulzrinne, H. and R. Hancock, "GIST: General Internet
Signalling Transport", RFC 5971, October 2010.
[RFC5973] Stiemerling, M., Tschofenig, H., Aoun, C., and E. Davies,
"NAT/Firewall NSIS Signaling Layer Protocol (NSLP)", RFC
5973, October 2010.
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Authors' Addresses
Cathy Zhou
Huawei Technologies
Bantian, Longgang District
Shenzhen 518129
P.R. China
Email: cathy.zhou@huawei.com
Tina Tsou
Huawei Technologies
Bantian, Longgang District
Shenzhen 518129
P.R. China
Email: Tina.Tsou.Zouting@huawei.com
Diego Lopez
Telefonica
Email: diego@tid.es
Georgios Karagiannis
University of Twente
Email: g.karagiannis@utwente.nl
Qiong Sun
China Telecom
No.118 Xizhimennei street, Xicheng District
Beijing 100035
P.R. China
Email: sunqiong@ctbri.com.cn
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