Network Working Group G. Karagiannis Internet-Draft W. Liu Intended status: Informational T. Tsou Expires: April 25, 2015 Huawei Technologies Q. Sun China Telecom Luis M. Contreras Telefonica P. Yegani Juniper Networks JF Tremblay Viagenie October 25, 2014 Problem Statement for Shared Unified Policy Automation (SUPA) draft-karagiannis-supa-problem-statement-02 Abstract As modern network management applications grow in scale and complexity, their demands and requirements on the supporting communication network increase. This is the root cause of one of the major challenges that network operators (service providers, SME, etc) are facing today. The operators are obliged to create a simplified view of their network infrastructure that can help network engineers to use such a simplified model rather than manipulating individual devices. In this context, providing network operators with a set of standard interfaces to configure and set policies at various points on their network is essential. This document describes what has to be addressed in order to equip service providers with the means to quickly and dynamically create/query/scale/update/ delete/ the services they want to offer. This may include a variety of different service enabling scenarios and in particular VPN and Inter-DC traffic steering and tunneling. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 25, 2015. Karagiannis, et al. Expires April 25, 2015 [Page 1] Internet-Draft SUPA Problem Statement October 2014 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 (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Inter-Data Center (DC) and VPN Use Cases . . . . . . . . . . . 5 4. Requirements/Objectives . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction Network operators are faced with networks of increasing size and complexity while trying to improve their quality and availability, as more and more services depend on them. Programmatic ways to configure networks, often called software-defined, are considered by many network operators in order to shift the balance in their favor. Currently, the separation of development and operation of network technologies leads to slow deployment of network functions/devices and poor user experiences. Providing means of exposing a view of the network to applications may provide significant improvements in configuration agility, error detection and uptime for operators. However, the real value behind central configuration schemes lies within the possible simplification through abstract models provided by such systems to applications and network services running above them (on the so-called northbound side). Well-designed simplified models are able to provide a wide range of granularity for various applications and network services needs, from the lower-level physical network to high-level application services. Karagiannis, et al. Expires April 25, 2015 [Page 2] Internet-Draft SUPA Problem Statement October 2014 1.1 Motivation As the underlying network infrastructure continues to grow, due to increasingly new services and applications, it becomes significantly more challenging than ever to maintain the network and deploy new services. Nowadays, network configuration, optimization and automation using software-defined networking tools and techniques, are being considered by many network operators in order to provide significant benefits in deployment agility and fast time to market. Shared Unified Policy Automation (SUPA) attempts to achieve this configuration automation by introducing multi-level and multi-technology network abstractions. It plans to create YANG model of general network topology and YANG model of service specific configuration to provide topology information as applications demand and map the network-wide configuration/topology into individual device-recognized configuration. This entails to defining standardized interfaces between applications and network domains (via network controllers) to enable automatic and programmable configuration required for proper operation of the network to deliver the target services. Several working groups in IETF such as I2RS (L3/ routing topologies), ALTO (cost maps), SFC (service chain), have already defined various schemes for the configuration of network devices and specific network controllers. However, none of these efforts offer a vendor-neutral standardized scheme for applications to transmit their needs to controllers. Figure 1 shows the SUPA architecture where applications can communicate with network controllers of all types, which can be for example single or multiple controllers. These network controllers can use any type of mechanisms for excahning information to and from NEs. In this architecture NEs can interact with local or remote network controllers (e.g., exchange configuration information, status, etc). Network controllers, exchange configuration information with NEs and derive the actual and detailed network topology model. When an application needs to use this network topology it applies NETCONF [RFC6241] or RESTCONF [ID.draft-ietf-netconf-restconf] and it sends a request to receive a service specific abstraction from the network controller(s). Subsequently, the network controller(s) provides, a service specific abstraction of the network topology to the application, which should be able to meet the requirements imposed by this application. Different types of applications may get different service specific abstractions of the same network topology from the network controller(s). For example, for the same actual network topology, a VPN network service will receive a different service specific abstraction of the network topology, than an inter Data Center (DC) network service. By using policies, e.g., for traffic steering, the application can instruct the network controller(s) to map the service specific abstractions to the actual (detailed) network topology and NE specific configuration. Karagiannis, et al. Expires April 25, 2015 [Page 3] Internet-Draft SUPA Problem Statement October 2014 The main goal of SUPA is to provide YANG models [RFC6020], [RFC6991] of vendor-neutral service specific abstractions for the VPN and Inter-DC traffic steering and tunneling network services. This is to allow applications to request these network services from network controller(s) of all types, e.g., single or multiple controllers. Such services can be quickly and dynamically created/deleted/updated, using proper mechanisms for exchanging information between the appropriate NEs. Examples of YANG-based data models for network topologies are provided in [ID.draft-contreras-supa-yang-network-topo]. A YANG Data model for SUPA configuration is provided in [ID.draft-zaalouk-supa-configuration-model]. The document [ID.draft-pentikousis-supa-mapping] describes guidelines for mapping high-level configuration and policy information into device-level configuration. This document is organized as follows. Section 2 presents the terminology. Section 3 provides a brief overview of the use cases associated with SUPA. The requirements/objectives are provided in Section 4. Section 5 provides the security considerations. The IANA considerations are given in Section 6. Section 7 gives the acknowledgements and Section 8 provides the list of references. ----------------------------------- | Applications | ----------------------------------- | \ | | \ | <------- service specific | \ | YANG models /NETCONF | \ | northbound interface | \ | ------------- -------------- mapping | | | | <--- service specific | Controller | | Controller | abstractions to | | | | network topology and --------------- ------------- configuration | | | | | | | | | | | | <------- NE/feature | | | | | | specific YANG | | | | | | models / NETCONF | | | | | | southbound interface NE1 NE2 NEn NE1 NE2 NEn Figure 1: SUPA architecture overview 2. Terminology Network Service: is the composition of network functions and defined by its functional and behavioural specification. The network service contributes to the behaviour of the higher layer service, which is characterized by at least performance, dependability, and security specifications. Karagiannis, et al. Expires April 25, 2015 [Page 4] Internet-Draft SUPA Problem Statement October 2014 Network Element: a physical or virtual entity that implements one or more network function(s). NEs can interact with local or remote network controllers in order to exchange information, such as configuration information and status. Service specific abstraction: an abstract view of the actual topology of a network, which is associated with a specific network service type, e.g., VPN or Inter-DC. 3. Inter-Data Center (DC) and VPN Use Cases This section briefly describes the use cases that are associated with different types of network services. The detailed description of these use cases is provided in other Internet draft(s). 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 networks, traffic is routed by 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. SUPA can be used to request the optimization of the traffic paths dynamically and has the ability to request load balancing between data centers and links, and direct customer traffic via network management policies. Path optimization can be accomplished using data models or software programs routines to differentiate customer based on their service class and/or QoS requirements. Moreover, when VPN tunnels are interconnecting DCs, SUPA can be used to dynamically reconfigure these VPN tunnels, e.g., L2VPN or L3VPN in order to avoid possible congested communication paths and improve end to end latency. Detailed descriptions of these use cases are provided in [ID.draft-cheng-supa-ddc-use-cases]. 4. Requirements/Objectives The SUPA architectural framework must support the following capabilities: o) Define network abstractions using Yang models for L0-L7 Network topologies with bi-directional and uni-directional links o) Map Service-Specific Yang models of both VPN tunneling and Inter-DC virtual links Network Configuration to NE-Specific configuration (i.e., Tunnel Policy and Traffic Steering Policy, etc.) Karagiannis, et al. Expires April 25, 2015 [Page 5] Internet-Draft SUPA Problem Statement October 2014 o) Specify how NEs can interact with local or remote network controllers (e.g., exchange configuration information, status, etc.). 5. Security Considerations Security is a key aspect of any protocol that allows state installation and extracting detailed configuration states of network elements. This places additional security measures on SUPA (e.g., authorization, and authentication of network services) that needs further investigation. 6. IANA Considerations This document has no actions for IANA. 7. Acknowledgements The authors of this draft would like to thank the following persons for the provided valuable feedback and contributions: Diego Lopez, 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, Tom Taylor, Kostas Pentikousis, Juergen Schoenwaelder, Eric Voit. 8. References 8.1. Normative References 8.2. Informative References [ID.draft-cheng-supa-ddc-use-cases] Y. Cheng, C. Zhou, G. Karagiannis, JF. Tremblay, "Use Cases for Distributed Data Center Applicatinos in APONF", IETF Internet draft (Work in progress), draft-cheng-supa-ddc-use-cases-01, October 2014 [ID.draft-contreras-supa-yang-network-topo] L.Contreras, Andrew Qu, "A YANG Data Model for Network Topologies", IETF draft (work in progress), draft-contreras-supa-yang-network-topo, September 18, 2004. [ID.draft-pentikousis-supa-mapping] K. Pentikousis, Junru Lin, Yiyong Zha, "SUPA Configuration and Policy Mapping", IETF Internet draft, draft-pentikousis-supa-mapping-00, September 23, 2014 [ID.draft-zaalouk-supa-configuration-model] A. Zaalouk, K. Pentikousis, W. Liu, "YANG Data Model for Configuration of Shared Unified Policy Automation (SUPA)", IETF draft, draft-zaalouk-supa- configuration-model-00, 22 September, 2014 [ID.draft-ietf-netconf-restconf] A. Bierman, M. Bjorklund, K. Watsen, R. Fernando, "RESTCONF Protocol", IETF Internet draft (work in progress), draft-ietf-netconf-restconf-03, October 2014 Karagiannis, et al. Expires April 25, 2015 [Page 6] Internet-Draft SUPA Problem Statement October 2014 [RFC6020] M. Bjorklund, "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010. [RFC6241] R. Enns, M. Bjorklund, J. Schoenwaelder, A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011. [RFC6991] J. Schoenwaelder, "Common YANG Data Types", RFC 6991, July 2013. Authors' Addresses Georgios Karagiannis Huawei Technologies Hansaallee 205, 40549 Dusseldorf, Germany Email: Georgios.Karagiannis@huawei.com 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 Luis M. Contreras Telefonica I+D Ronda de la Comunicacion, Sur-3 building, 3rd floor Madrid 28050 Spain Email: luismiguel.contrerasmurillo@telefonica.com URI: http://people.tid.es/LuisM.Contreras/ Parviz Yegani JUNIPER NETWORKS 1133 Innovation Way Sunnyvale, CA 94089 Email: pyegani@juniper.net Karagiannis, et al. Expires April 25, 2015 [Page 7] Internet-Draft SUPA Problem Statement October 2014 Jean-Francois Tremblay Viagenie inc. Email: jean-francois.tremblay@viagenie.ca Karagiannis, et al. Expires April 25, 2015 [Page 8]