Network Working Group Y. Luo Internet-Draft L. Ou Intended status: Informational China Telcom Co., Ltd. Expires: September 6, 2018 X. Huang Tencent S. Zhuang Z. Li Huawei March 5, 2018 Traffic Steering Based on BGP Controller draft-luo-grow-bgp-controller-based-ts-00 Abstract Due to the dramatically increased network traffic and the desire of differentiated services, it is essential for operators to provide the traffic steering service under limited network resources and maximize their benefits at the same time. The traditional method for traffic steering depends on static configuration which is time consuming and error-prone. As development of SDN, the controller is introduced for traffic steering with the global view of network topology and route information. This document describes typical use cases for traffic steering services and proposes the traffic steering solution based on BGP controller. 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]. 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 https://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." Luo, et al. Expires September 6, 2018 [Page 1] Internet-Draft Traffic Steering Based on BGP Controller March 2018 This Internet-Draft will expire on September 6, 2018. Copyright Notice Copyright (c) 2018 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 (https://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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Architecture . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1. Network Topology Collection . . . . . . . . . . . . . . . 4 3.2. Route Information Collection . . . . . . . . . . . . . . 4 3.3. Route Control . . . . . . . . . . . . . . . . . . . . . . 4 4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. Business-oriented Steering . . . . . . . . . . . . . . . 5 4.1.1. An Example of Preferential Users . . . . . . . . . . 5 4.1.2. An Example of Preferential Services . . . . . . . . . 6 4.2. Traffic Congestion Mitigation . . . . . . . . . . . . . . 6 4.2.1. An Example of Congestion Mitigation in Core . . . . . 7 4.2.2. An Example of Congestion Mitigation among ISPs . . . 7 4.2.3. An Example of Congestion Mitigation at International Edge . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 9.1. Normative References . . . . . . . . . . . . . . . . . . 10 9.2. Informative References . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction Transporting data to their users through the network is a fundamental service that can benefit both providers and consumers. Since data/ information transport is playing a key role nowadays, operators have Luo, et al. Expires September 6, 2018 [Page 2] Internet-Draft Traffic Steering Based on BGP Controller March 2018 to face this increasing challenge through satisfying services with differentiated criterias, such as latency, throughput, reliability and even user-defined constraints. Moreover, the internet traffic changes rapidly and is hard to be predicted, so there is chance that the network will be congested. However, the network capacity expansion takes time and could not meet the differentiated service requirement or solve the congestion problem in time. As a result it is nessesary to introduce traffic steering techniques into the network. The traditional method for traffic steering depends on static configuration which is time consuming and error-prone. As development of SDN, the controller is introduced for traffic steering with the global view of network topology and route information. This document describes typical use cases for traffic steering services and proposes the traffic steering solution based on BGP controller. 2. Terminology o QoS: Quality of Service o ISP: Internet Service Provider o MAN: Metropolitan Area Network o OTT: Over the Top o OTTSP: Over the Top Service Provider, or Content Operator o AR: Access Router 3. Architecture The following figure shows the solution of traffic steering through BGP controller. Luo, et al. Expires September 6, 2018 [Page 3] Internet-Draft Traffic Steering Based on BGP Controller March 2018 +-------------------+ | | | BGP | |----------| Controller |--------| | | | | | +-------------------+ | | ^ | ^ | Route Control / | \ Route Control | / | \ | | Topo/Route | Topo/Route | | Info Collection | Info Collection | | / | \ | \|/ / | \ \|/ +--------+ +--------+ +--------+ | CLIENT | | CLIENT | | CLIENT | | | ...... | | ...... | | | (PE) | | (P) | | (PE) | | | | | | | +--------+ +--------+ +--------+ Figure 6 Traffic Steering through BGP Controller 3.1. Network Topology Collection In order for traffic steering the BGP Controller must get the topology of the whole network. [RFC7752] can be used to collect the topology information of the network domain and [I-D.ietf-idr-bgpls-segment-routing-epe] can be used to collect the inter-domain topology information. 3.2. Route Information Collection In order to steering traffic in and/or out the network, the BGP controller must learn the existing BGP route information in the network. There are several ways to learn the BGP route information from the network: 1. The BGP controller can work as the route reflector so that it can directly learn the BGP route from the client. 2. The BGP controller can also learn the BGP route through BGP Mornitoring Protocol [RFC7854]. 3.3. Route Control Based on the servie requirement BGP controller can calculate the traffice steering policy for the specific BGP route. The traffice steering policy should be advertised from the BGP controller along Luo, et al. Expires September 6, 2018 [Page 4] Internet-Draft Traffic Steering Based on BGP Controller March 2018 with the route information to the clients in the network to take effect. BGP, PCE and Netconf can be used for the advertisement. 4. Use Cases 4.1. Business-oriented Steering It is a reasonable commercial way to provide multiple paths to the same destination with differentiated experiences to preferential users/services. This is an efficient approach to maximize providers' network resources as well as their profit and offer more choices to network users. 4.1.1. An Example of Preferential Users +----------+ | HongKong | --+----------+-- --- | --- --- | --- -- | -- +----------+ | +----------+ |Singapore | | | LA | +----------+ | +----------+ -- |Path1 -- --- | --- Path2 --- | --- Path3 --+----------+-- | Sydney | +----------+ | | +-----------+-----------+ | | | +-------+ +-------+ +-------+ |Silver | |Gold | |Bronze | |Users | |Users | |Users | +-------+ +-------+ +-------+ Figure 1 Differentiated Path Selection for Different User In the above ISP network, there are three kinds of users in Sydney, saying Gold, Silver and Bronze, and they wish to visit website located in HongKong. The ISP provides three different paths with different experiences according to users' priority. The Gold Users may use Path1 with less latency and loss. The Silver Users may use the Path2 through Singapore with less latency but maybe some congestion there. The Bronze Users may use Path3 through LA with some latency and loss. Luo, et al. Expires September 6, 2018 [Page 5] Internet-Draft Traffic Steering Based on BGP Controller March 2018 4.1.2. An Example of Preferential Services * * City A * City B * City C * * * +-----+ * * |Users| * * +-----+ * * | * +-----------+-----------+ | * | * | +-----+ * +-----+ * +-----+ | R11 |-----| R12 |-----| R13 | +-----+ * +-----+ * +-----+ ISP | * | * | *****|***********|***********|********* | * | * | | * | * | OTT +-----+ * +-----+ * +-----+ | R21 |-----| R22 |-----| R23 | +-----+ * +-----+ * +-----+ | * | * | +-----------+-----------+ * | * * +-----+ * +-------+ * | AR |--------|Content| * +-----+ * |Server | +-------+ Figure 2 Differentiated Path Selection for Different Services As depicted above, the OTTSP has 3 exits with one ISP, which are located in City A, City B and City C. The content is obtained from Content Server and send to the exits through AR. an OTTSP may make its steering strategy based on different services. For example, the OTTSP in the graph above may choose exit R21 for video service and exit R22 for web service, which REQUIREs a mechanism/system exists to identify different services from traffic flow. 4.2. Traffic Congestion Mitigation It is a persistent goal for providers to increase the utilization ratio of their current network resources, and to mitigate the traffic congestion. Traffic congestion is possible to happen anywhere in the ISP network(MAN, IDC, core and the links between them), because internet traffic is hard to predict. For example, there might be some local online events that the network operators didn't know beforehead, or some sudden attack just happened. Even for the big events that can be predicted, such as annual online discount of Luo, et al. Expires September 6, 2018 [Page 6] Internet-Draft Traffic Steering Based on BGP Controller March 2018 e-commerce company, or IOS update of Apple Inc, we could not guarantee there is no congestion. Since the network capacity expansion is usually an annual operation, there could be delay on any links of the engineering. As a result, the temporary traffic steering is always needed. The same thing happens to the OTT networks as well. It should be noted that, the traffic steering is absolutely not a global behavior. It just acts on part of the network, and it's temporary. 4.2.1. An Example of Congestion Mitigation in Core Core +----------+ | Core A | +------+ --+----------+-- +------+ |MAN C1|-+ --- --- +-|MAN D1| +------+ | --- --- | +------+ | -- -- | | +----------+ +----------+ | +-| Core C | | Core D |-+ | +----------+ +----------+ | | -- -- | +------+ | --- --- | +------+ |MAN C2|-+ --- --- +-|MAN D2| +------+ --+----------+-- +------+ | Core B | +----------+ Figure 3 An Example of Congestion Mitigation in Core As depicted above, traffic from MAN C1 to MAN D2 follows the path Core C->Core B->Core D as the primary path, but somehow the load ratio becomes too much. It is reasonable to transfer some traffic load to less utilized path Core C->Core A->Core D when the primary path has congestion. 4.2.2. An Example of Congestion Mitigation among ISPs Luo, et al. Expires September 6, 2018 [Page 7] Internet-Draft Traffic Steering Based on BGP Controller March 2018 * * City A * City B * City C * * +-------+ * +-------+ * +-------+ |IXP A1 |----|IXP B1|---|IXP C1 | +-------+ * +-------+ * +-------+ ISP 1 | * | * | | *******|*************|*********|**|********** | +----------|---------+ | | | * | * | ISP 2 | | * | * | +------+ * +------+ * +------+ |IXP A2|----|IXP B2|----|IXP C2| +------+ * +------+ * +------+ | * | * | | * | * | +-------+ * +-------+ * +-------+ |Core A |----|Core B |---|Core C | +-------+ * +-------+ * +-------+ Figure 4 An Example of Congestion Mitigation among ISPs As depicted above, ISP1 and ISP2 are interconnect by 3 exits which are located in 3 cities respectively. The links between ISP1 and ISP2 in the same city are called local links, and the rest are long distance links. Traffic from IXP C1 to Core A in ISP 2 usually passes through link IXP C1->IXP A2->Core A. This is a long distant route, directly connecting city C and city A. Part of traffic could be transferred to link IXP C1->IXP B1->IXP A1->IXP A2->Core A when the primary route congest. 4.2.3. An Example of Congestion Mitigation at International Edge An ISP usually interconnects with more than 2 transit networks at the international edge, so it is quite common that multiple paths may exist for the same foreign destination. Usually those paths with better QoS properties such as latency, loss, jitter and etc are often preferred. Since these properties keep changing from time to time, the decision of path selection has to be made dynamically. Luo, et al. Expires September 6, 2018 [Page 8] Internet-Draft Traffic Steering Based on BGP Controller March 2018 ******************************** * * * AS C1 * * * AS Y1 * * * +---+ +---+ * +-----------+ * /| B |---------| C |-----| Transit A | AS Z1 * / +---+\ +---+ * +-----------+-- * / | \\ // | * -- +-------------+ *+---+/ | \\// | * --| | *| A | | //\ | * |Destination H| *+---+\ | // \\ | * --| | * \ | / \ | * -- +-------------+ * \ +---+ +---+ * +-----------+-- * \| D |---------| E |-----| Transit B | * +---+ +---+ * +-----------+ * * * IP Core * AS X1 * * ******************************** Figure 5 An Example of Congestion Mitigation at International Edge As depicted above, the traffic to the foreign destination H from IP core network (AS C1) has two choices on transit network, saying Transit A and Transit B. Under normal conditions, Transit B is the primary choice, but Transit A will be preferred when the QoS of Transit B gets worse. As a result, the same traffic will go through Transit A instead. 5. Contributors Nan Wu Huawei Email: eric.wu@huawei.com 6. IANA Considerations This document has no request to IANA. 7. Security Considerations This document has no security issue introduced. 8. Acknowledgements TBD. Luo, et al. Expires September 6, 2018 [Page 9] Internet-Draft Traffic Steering Based on BGP Controller March 2018 9. References 9.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . 9.2. Informative References [I-D.ietf-idr-bgpls-segment-routing-epe] Previdi, S., Filsfils, C., Patel, K., Ray, S., and J. Dong, "BGP-LS extensions for Segment Routing BGP Egress Peer Engineering", draft-ietf-idr-bgpls-segment-routing- epe-14 (work in progress), December 2017. [I-D.li-idr-flowspec-rpd] Li, Z., Ou, L., Luo, Y., Lu, S., Zhuang, S., and N. Wu, "BGP FlowSpec Extensions for Routing Policy Distribution (RPD)", draft-li-idr-flowspec-rpd-02 (work in progress), June 2016. [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and S. Ray, "North-Bound Distribution of Link-State and Traffic Engineering (TE) Information Using BGP", RFC 7752, DOI 10.17487/RFC7752, March 2016, . [RFC7854] Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP Monitoring Protocol (BMP)", RFC 7854, DOI 10.17487/RFC7854, June 2016, . Authors' Addresses Yujia Luo China Telcom Co., Ltd. 109 West Zhongshan Ave,Tianhe District Guangzhou 510630 China Email: luoyuj@gsta.com Luo, et al. Expires September 6, 2018 [Page 10] Internet-Draft Traffic Steering Based on BGP Controller March 2018 Liang Ou China Telcom Co., Ltd. 109 West Zhongshan Ave,Tianhe District Guangzhou 510630 China Email: oul@gsta.com Xiang Huang Tencent Email: terranhuang@tencent.com Shunwan Zhuang Huawei Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China Email: zhuangshunwan@huawei.com Zhenbin Li Huawei Huawei Bld., No.156 Beiqing Rd. Beijing 100095 China Email: lizhenbin@huawei.com Luo, et al. Expires September 6, 2018 [Page 11]