INTERNET-DRAFT X.Wei Intended Status: Informational Huawei Technologies Expires: January 1, 2015 June 30, 2014 Interaction between SFC network and 3GPP network draft-wei-sfc-mobile-consideration-00 Abstract This document provides a discussion of how SFC (Service Function Chain) domain could interact with carrier network to provide network service for traffic. Here LTE (Long Term Evolution) network is used as an example of carrier network for discussion. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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. 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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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Interaction between LTE network and SFC domain . . . . . . . . 4 2.1 Interaction model . . . . . . . . . . . . . . . . . . . . . 4 2.2 Information exchange . . . . . . . . . . . . . . . . . . . 6 3 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 4 Security Considerations . . . . . . . . . . . . . . . . . . . . 6 5 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 6 6 References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.1 Normative References . . . . . . . . . . . . . . . . . . . 6 6.2 Informative References . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 X.Wei Expires January 1, 2015 [Page 2] INTERNET DRAFT Re-classification analysis in SFC June 30, 2014 1 Introduction Different kinds of network Service Function (SF) have been deployed in current network to provide network service for traffic. But current SF deployments are tightly coupled to network topology and physical resources, and this limits the ability of an operator to introduce new services and/or service functions. To overcome the disadvantages of current SF deployments, flexible SFC (Service Function Chain) is under discussion in IETF [SFC PS]. Though SFC domain is typically deployed by the owner of carrier network, here we treat SFC domain and carrier network as two separate network domain. A typical relationship between carrier network and SFC domain is shown in Figure 1. When network traffic goes through SFC domain, the SFC domain needs to know how to steer the traffic, i.e. which service chain the traffic should pass. The carrier network and SFC domain should interact properly in order to provide network service to traffic. +---------------+ traffic +----------+ traffic--------+ |Carrier Network| <=======> |SFC domain| <=====>|Internet| +---------------+ +----------+ +--------+ Figure 1 Relationship between carrier network and SFC domain LTE (Long Term Evolution) network [TS23.401] is standardized by 3rd Generation Partnership Project (3GPP), the basic architecture of LTE network is shown in Figure 2, three network entities including eNodeB, SGW and PDN-GW form the data path for user's traffic from UE to IP service network, and MME (Mobility Management Entity) acts as a central control point of the network. +--------+ | IP | S1-MME +-------+ S11 |Networks| +----|----| MME |----|----+ +--------+ | | | | |SGi | +-------+ | S5/ | +----+ LTE-Uu +-------+ S1-U +-------+ S8 +-------+ |UE |----|---|eNodeB |---|-----------------| SGW |--|---|PDN-GW | | |========|=======|=====================|=======|======| | +----+ +-------+ +-------+ +-------+ Figure 2 Basic LTE network architecture LTE network connects to IP service network through SGi interface X.Wei Expires January 1, 2015 [Page 3] INTERNET DRAFT Re-classification analysis in SFC June 30, 2014 [TS29.061]. Gi-LAN service area is presently used by mobile network operator to differentiate their services to their subscribers; mobile network operator could deploy any kinds of SFs, e.g. Firewall, video optimizer, NAT (Network Address Translator), to provide network service for user's traffic. +-----------+ SGi +------+ +-----------+ |LTE network| <======> |Gi-LAN|<========>|IP Networks| +-----------+ +------+ +-----------+ Figure 3 Gi-LAN for LTE network This document use LTE network as an example to illustrate how carrier network and SFC domain could cooperate to provide network service to traffic. 1.1 Terminology 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]. SFC domain: or SFC network, a network that implements SFC. 2. Interaction between LTE network and SFC domain In this section, we will discuss how SFC domain could provide network service for traffic in LTE network. 2.1 Interaction model Before the discussion of interaction between LTE network and SFC domain, we first introduce the concept of Logical Service Function Chain (LSFC) and Physical Service Function Chain (PSFC). LSFC is a service function chain which is consisted of a list of SF type, and no specific SF instance is included in LSFC. PSFC is a service function chain which is consisted of a list of SF instance, so PSFC could be viewed as an instance of LSFC. Considering of the requirements of load balance, there could be more than one instance for one type of SF, so a LSFC could be mapped into one or more PSFC. LSFC stands for a requirement of service function chain for certain traffic, and PSFC is a physical implementation that satisfies the requirement. X.Wei Expires January 1, 2015 [Page 4] INTERNET DRAFT Re-classification analysis in SFC June 30, 2014 When we take LTE network and SFC domain as two separate domains, LTE network plays the role of producing network service requirements and SFC domain plays the role of providing network service for LTE network's traffic. An overview of interaction between LTE network and SFC domain is depicted in Figure 4. LTE network creates LSFC for traffic and sends the LSFC to SFC domain, and then SFC domain is in charge of translating LSFC to PSFC. Besides LSFC, additional information such as subscriber ID, that might be used but could not be accessed directly by SFC domain, will also be conveyed in service chain request procedure. service chain request +----------------------------+ | | | | +------|----+ traffic +----V-----+ |LTE Network| <==============> |SFC domain| +-----------+ +----------+ Figure 4 Overview of Interaction between LTE network and SFC domain There are sorts of information that could be used in creating of LSFC: - Mobile user's subscription information. For example, the network operator could provide video optimization service for gold and silver user's video traffic, but not for bronze user's traffic. - Network status information. For example, the radio access type that the mobile user currently attached to or the network congestion level could affect the choice of video optimizer for video traffic. - Agreement between content provider and network operator. Content provider, e.g. YouTube, could rent TCP optimization or video optimization function for its traffic, so for the traffic of content provider that has service agreement with network operator certain service function could be implemented. - Application Characteristics. Application characteristics play very important role in creating service chain for the traffic, different kinds of application traffic, such as Web application and video application, would definitely go through different service chain. - QoS information of the service. QoS information of LTE network traffic could affect the choice of specific SF. Per operator's consideration, the combination of different information can be used in creating LSFC for the traffic. X.Wei Expires January 1, 2015 [Page 5] INTERNET DRAFT Re-classification analysis in SFC June 30, 2014 2.2 Information exchange This sub-section discusses what information elements should be conveyed in service chain request procedure from LTE network to SFC domain as depicted in Figure 4. As discussed in sub-section 2.1, LSFC will be conveyed in service chain request. +-----------+---------------------------------------------------+ | Match rule| To identify which traffic the LSFC is specific to.| +-----------+---------------------------------------------------+ | LSFC | To specify network service function chain that | | | will act on the traffic. | +-----------+---------------------------------------------------+ | Additional| SFC related auxiliary information such as User's | | info | Subscriber ID. | +-----------+---------------------------------------------------+ 3 IANA Considerations This document requires no requirement for IANA. 4 Security Considerations Security related issues is not involved. 5 Acknowledgments Many thanks to John Kaippallimalil and Chunshan Xiong (Sam) for their valuable comments. 6 References 6.1 Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011. [RFC6733] Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn, Ed., "Diameter Base Protocol", RFC 6733, October 2012. X.Wei Expires January 1, 2015 [Page 6] INTERNET DRAFT Re-classification analysis in SFC June 30, 2014 6.2 Informative References [Krishnan] R. Krishnan et al. "draft-krishnan-sfc-long-lived-flow- use-cases", April 21, 2014 [SFC PS] P. Quinn et al. "draft-ietf-sfc-problem-statement-07", June 24, 2014 Authors' Addresses Xinpeng Wei EMail: weixinpeng@huawei.com X.Wei Expires January 1, 2015 [Page 7]