Problem Statement for Application Policy on Network Functions (APONF)
draft-karagiannis-aponf-problem-statement-01

Network Working Group                                     G. Karagiannis
Internet-Draft                                      University of Twente
Intended status: Informational                                    W. Liu
Expires: December 30, 2014                                       T. Tsou
                                                     Huawei Technologies
                                                                  Q. Sun
                                                           China Telecom
                                                                D. Lopez
                                                              Telefonica
                                                           June 30, 2014

   Problem Statement for Application Policy on Network Functions (APONF)
                  draft-karagiannis-aponf-problem-statement-01

Abstract

   As more and more modern network management applications grow in scale 
   and complexity, their demands and requirements on the supporting 
   communication network will increase. 
   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 
   application programming interfaces to such service developers. The 
   main goal of APONF is to (1) communicate the up to date abstract view 
   of the network between the network management application systems and 
   network management and controlling systems and (2) map the abstract 
   view of the network into specific network management policies, i.e., 
   device level configuration models. 

Status of This Memo

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Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   This document is subject to BCP 78 and the IETF Trust's Legal
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   (http://trustee.ietf.org/license-info) in effect on the date of
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   described in the Simplified BSD License.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
   4.  Requirements/Objectives . . . . . . . . . . . . . . . . . . . . 7
   5   Relationships between APONF and other IETF Working Groups . . . 7
   6.  Existing Protocols and Methods . . . . . . . . . . . . . . . .  8
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 9
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   Today, 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. This also implies that demands and requirements of such 
   new services on the supporting communication network will increase. 

   Furthermore, and especially for cloud applications, the cloud tenants 
   and developers usually need to use the communication network 
   capabilities, such as dynamic network management easily, accurately 
   and efficiently. In this way, the deployment of new applications and 
   services may be accelerated and the user experience can be improved.

   Moreover, the Development Operations (DevOps), see e.g., [DevOps], is 
   another network development trend which orchestrates the complex 
   interdependent processes associated with software development and 
   IT operations in order to accelerate the production and roll out of 
   software products and services. 

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   Currently, the separation of development and operation of network 
   technologies leads to slow deployment of network functions/devices 
   and poor user experiences. The communication network needs to provide 
   graceful adjustment capabilities in order to accommodate the diverse 
   needs of applications and the rapid network evolution.

   In addition, 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. An abstract view of a network 
   infrastructure can be realized using a network configuration model, 
   that provides a declarative configuration and a network topology 
   model that describes a multi-layer network. Network management 
   applications are Operational Support System (OSS) like applications 
   that help a communication service provider to monitor, control, 
   analyze and manage a communication network.

   In this context, network management applications can be used to 
   provide the required configuration and 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 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. 

   Furthermore, there are currently no IETF solutions that can be used 
   to provide the necessary configuration interfaces to service 
   developers to program the abstract view of a network infrastructure. 
   Currently, the Application Enabled Collaborative Network (AECON) 
   activity can provide these necessary solutions.

   Moreover, there are no IETF solutions that can directly be used to 
  (1)enable the streaming transfer of bulk-variable/data of SFP based 
   network configuration and network topology models between network 
   management application systems and network management and controlling 
   systems, (2) map the SFP based network configuration and network 
   topology models into specific device level configuration models.

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   The APONF activity can provide a solution to this challenge. A 
   possible signaling protocol framework that can be enhanced and used 
   is the flexible IETF signaling protocol NSIS, see [RFC4080], 
   [RFC5971], [RFC5973].

   The main goal of APONF is to:
     o) enable the streaming transfer of bulk-variable/data of the up to 
        date SFP based network configuration and network topology models 
        between network management application systems and the network 
        management and controlling systems, by using and extending the 
        IETF Next Steps in Signaling Protocol (NSIS).
     o) map the SFP based network configuration and network topology 
        models into specific network management policies, i.e., 
        device level configuration models. 

   This document is organized as follows. Section 2 presents the 
   terminology. Section 3 provides a brief overview of the use cases 
   associated with APONF. The requirements/objectives are provided in 
   Section 4. Section 5 presents the relationships between APONF and 
   other IETF Working Groups and other IETF activities. The existing 
   IETF protocols and methods that can be used by the APONF solutions 
   are given in Section 6. Section 7 provides the security   
   considerations. The IANA considerations are given in Section 8. 
   Section 9 gives the acknowledgements and Section 10 lists the used 
   references.

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: Operational Support System (OSS) like 
   applications that help a communication 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.

   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.

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   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.  Use Cases

   This section briefly describes the use cases that are associated with 
   different types of network management applications. The detailed    
   description of these use cases is provided in other Internet 
   draft(s).

3.1 Distributed Data Center 

   A large-scale IDC (Inter Data Center) operator provides server 
   hosting, bandwidth, and value-added services to enterprises and ISPs,  
   and has more than 10 data centers and more than 1Tbs bandwidth in a 
   capital city. In current IDC network, traffic is 
   routed via configuring policy routes and adjusting routes 
   prioritization to choose an outgoing link. This type of static 
   provisioning comes with high costs and poor operability. Furthermore, 
   the link bandwidth resources in the data centers are not efficiently 
   utilized.  
   Services usually do not have consistent bandwidth requirements at
   all times of a day, e.g. video ISP usually require more
   bandwidth at non-working hours but require less bandwidth at working
   hours.  Some customers have relative high QoS requirement for their
   services, e.g. IM (Instant Messaging).  Static bandwidth and QoS 
   provisioning for all the customers and services is not reasonable and 
   not a cost-effective solution.
   APONF can be used to optimize the traffic paths dynamically and  
   have the ability to load balance between data centers and links, and 
   direct customer traffic via network management policies (e.g., 
   models, software programs routines) based on customer grade and QoS 
   requirements.  

3.2 IPv6 transition 
 
   The IPv6 transition has been an ongoing process throughout the world
   due to the exhaustion of the IPv4 address space.  However, this
   transition leads to costly end-to-end network upgrades and poses new
   challenges of managing a large number of devices with a variety of
   transitioning protocols.  While IPv6 transition tools exist, there
   are still new challenges to be solved.  Operators may need various 
   types of IPv6 transition technologies depending on performance 
   requirements, deployment scenarios, etc.

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   To address these difficulties, APONF can be used as the software 
   defined unifying approach that can provide a unified way to deploy 
   IPv6 in a cost-effective, flexible manner.

3.3. Virtualized Enterprise Applications

   Virtualized Enterprise applications make the Virtualized Network 
   Function (VNF) functionality available to enterprise users as a 
   service, comparable to the cloud computing concept denoted as the 
   Software as a Service (SaaS), see [NIST SP 800-146]. 
   Virtualized Enterprise application policies include dynamic 
   orchestration of virtualized network functions, dynamic 
   increase/decrease of network bandwidth, pay as you go billing and 
   charging. 
   GiLAN is another important application of network function 
   virtualization. In mobile core networks, it is preferable that QoS 
   provisioning and network function requirements are different for 
   subscribers with different profiles. In such scenarios, specialized 
   network management applications such as BSS/OSS can send application 
   based demands to a policy decision point, which further map these 
   application based demands to GiLAN specific VNF policies, and realize 
   the required QoS and with appropriate network functions, for example, 
   for dynamic path reconfiguration.

   APONF can be used to support the dynamic network reconfiguration 
   demands imposed by such virtualized enterprise applications.

3.4.  Source Address Validation and Traceback (SAVI)

   It has been long known that the IPv4/IPv6 transition makes the 
   Tracking and validation of source IP address thorny.  Whenever an 
   IPvX packet is translated into an IPvY packet, there are three 
   Troublesome issues: 1. how to track the origin of the IPvY packet 
   which is actually in the IPvX world? 2. how to validate the IPvX 
   packet at the edge of the IPvY world to prevent possible spoofing? 3. 
   how to protect the IPvY address from being spoofed in the IPvY world?
   SAVI[RFC7039] has given the source address validation solutions for
   both IPv4 and IPv6.  
   In order to address the above issues, APONF can be used to block or 
   permit the traffic based on the validation of the source address.

  3.5 Using the abstract view of network by service developers

   This use case description argues that service developers can profit 
   by using the abstract view of the network during the programming and 
   development process instead of manipulating individual devices.
   In this way one can write software that programs an arbitrary 
   network. 
   APONF can be used to interface the programmed arbitrary network 
   into network management policies, i.e., device configuration 
   models.

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   4. Requirements/Objectives

   The requirements/objectives that need to be supported by the APONF 
   methods, models and protocol solutions are the following ones:

      o) monitor and verify the freshness of the SFP based network 
         configuration and network topology models

      o) extend the IETF NSIS protocol to securely and efficiently 
         distribute the SFP based network configuration and network 
         topology models between network management applications systems 
         (e.g., OSS) and the network management and/or controlling 
         systems.

      o) use 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:

           a) encapsulating, de-encapsulating packets associated with a 
            flow into a tunnel (for example, VPN service, IPv6 
            transition service demands on the network)

           b) 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).

            c) configure and dynamically reconfigure data centers to the 
            steer and reroute traffic associated with a specific flow

            d) configure and dynamically reconfigure data centers to  
            change priorities of different types of traffic associated 
            with a specific flow

            e) logging the traffic associated with a flow for network 
            security service, optimization of the traffic based on the 
            IETF ALTO [ALTO] 

            f) other actions defined by the administrator

      o) specify the Authentication Authorization and Accounting (AAA) 
         method

5. Relationships between APONF and other IETF Working Groups

   The following relationships between APONF and other IETF WGs have 
   been identified:

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   IETF SFC WG: the main goal is 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 denoted as the 
   Service Function Path (SFP). This will enable the development of 
   suitable models for network configuration and network topology. 
   APONF can make use of such network configuration and network topology 
   models specified by the IETF SFC.

   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. AECON 
   can be used to provide the necessary configuration interfaces to 
   service developers to program the abstract view of a network 
   infrastructure. The AECON activity can be used to provide the 
   necessary configuration interfaces to service developers to program 
   the SFP based abstract view of a network infrastructure. 

   APONF is different than existing WGs and other IETF activities, due 
   to the fact that APONF is the only activity that: 
     o) enables the streaming transfer of bulk-variable/data of the up 
        to date SFP based network configuration and network topology 
        models between network management application systems and the 
        network management and controlling systems, by using and 
        extending the IETF Next Steps in Signaling Protocol (NSIS).
     o) map the SFP based network configuration and network topology 
        models into specific network management policies, i.e., 
        device level configuration models. 

6.  Existing Protocols and Methods

   The APONF protocol and mechanisms will have an impact on layers 4 and 
   above. 
   The IETF signaling protocol NSIS, see [RFC4080], [RFC5971], [RFC5973] 
   is the signaling protocol framework that can be enhanced and used 
   for the streaming transfer of bulk-variable/data of SFP based network 
   configuration and network topology models between network management 
   application systems and network management and controlling systems.
  
   Currently NSIS is an on path protocol (supports only signaling for 
   entities that are part of the data plane), but APONF needs to use an 
   off path protocol (i.e., support signaling for entities that are not 
   located on the data plane). Therefore, NSIS needs to be extended in 
   two ways:

     1) Extend NSIS GIST [RFC5971] in such a way that it can be used  
     for off-path support
     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. 

   The following activities are out of the APONF scope:

   o) the generation of the abstract view of the network infrastructure  
   using an SFP based network configuration and network topology models,

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   o) the necessary configuration interfaces to service 
      developers to program the abstract view of a network 
      infrastructure. 

   o) definition of the used SFP based network configuration and    
      network topology models 

  o) the specification of the network management policies and their 
     associated device configuration models

7.  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.

8.  IANA Considerations

   This document has no actions for IANA.

9.  Acknowledgements

   The authors of this draft would like to thank the following 
   persons for the provided valuable feedback: Spencer Dawkins, Jun Bi, 
   Xing Li,  Chongfeng Xie, Benoit Claise, Ian Farrer, Marc 
   Blancet, Zhen Cao, Hosnieh Rafiee, Mehmet Ersue, Simon Perreault, 
   Fernando Gont, Jose Saldana.

10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
   Requirement Levels", BCP 14, RFC 2119, March 1997.

10.2.  Informative References

   [ALTO] R. Alimi, R. Penno, Y. Yang, "ALTO Protocol", IETF Internet 
    draft (work in progress), March 2014

   [DevOps] DevOps website, http://devops.com/

   [NIST SP 800-146] Badger et al.: "Draft Cloud Computing Synopsis and 
   recommendations", NIST specifications, May 2011.

   [RFC4080] R. Hancock, G. Karagiannis, J. Loughney,  S. Van den Bosch, 
   "Next Steps in Signaling (NSIS): Framework", IETF RFC 4080, June 2005

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   [RFC5971] H. Schulzrinne, R. Hancock, "GIST: General Internet 
   Signalling Transport", IETF RFC 5971, October 2010

   [RFC5973] M. Stiemerling, H. Tschofenig, C. Aoun, E. Davies, 
   "NAT/Firewall NSIS Signaling Layer Protocol (NSLP)", IETF RFC 5973, 
   October 2010

   [RFC7039] J. Wu, J. Bi, M. Bagnulo, F. Baker, C. Vogt, "Source 
   Address  Validation Improvement (SAVI) Framework", IETF RFC 7039,  
   October 2013.

   [SFC] IETF SFC (Service Function Chaining) WG charter,  
   http://datatracker.ietf.org/wg/sfc/charter/

Authors' Addresses

   Georgios Karagiannis
   University of Twente

   Email: g.karagiannis@utwente.nl

   Will(Shucheng) Liu
   Huawei Technologies
   Bantian, Longgang District
   Shenzhen  518129
   P.R. China

   Email: liushucheng@huawei.com

   Tina Tsou
   Huawei Technologies
   Bantian, Longgang District
   Shenzhen  518129
   P.R. China

   Email: Tina.Tsou.Zouting@huawei.com

   Qiong Sun
   China Telecom
   No.118 Xizhimennei street, Xicheng District
   Beijing  100035
   P.R. China

   Email: sunqiong@ctbri.com.cn

   Diego Lopez
   Telefonica

   Email: diego@tid.es

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