Enabling Agile Service Chaining with Service Based Routing

Enabling Agile Service Chaining with Service Based Routing

Contents Abstract...1 1. Introduction...1 2. Huawei s SBR Solution for Agile Service Chaining...3 2.1. Architecture Overview...3 2.2. Multi-Dimensional Policy Control...4 2.3. Flexible Deployment...5 3. Evolution to SDN based SBR...6 4. Benefits of Huawei SBR Solution...7 5. Conclusion...7 6. Annex: Abbreviation...8

Abstract Service Based Routing (SBR) is an efficient means for chaining service enablers as a Value- Added Service (VAS) that are provided for the user data traffic in mobile networks. The Mobile Service Zone, the part of the mobile network that provides operator specific VAS, requires continuous enhancement and expansion for keeping pace with the steadily growing traffic and the change in type of traffic. Deploying service enablers offers new ways for creating innovative value added services and monetizing mobile network assets. This paper introduces Huawei's SBR solution that provides a flexible, scalable and future proof architecture for the mobile service zone. The solution selectively steers traffic to the desired service enablers in the specific order for composing the VAS. Powerful policies are described using a multi-dimensional policy control model which is enabled by the 3GPP Policy Control and Charging (PCC) architecture. Huawei s SBR solution offers different deployment options enabling operators to customize their Mobile Service Zone according to their needs. These deployments remain open for future evolution. The Huawei SBR deployments can smoothly evolve to employ Software-Defined Network (SDN) capabilities thereby protecting investments in SBR and providing enhanced flexibility and performance for creation and provision of value added services. 1. Introduction Mobile networks are typically separated into two zones for the mobile broadband traffic. One is the Mobile Pipe Zone, which may be described as consisting of radio access and core networks, providing bearer services for carrying mobile broadband traffic. The other zone is the Mobile Service Zone, allocated between the bearer services or the Mobile Pipe Zone and the Internet, with a collection of service enablers for providing Value Added Services (VAS). These service enablers include, for example, traffic compression, video optimization, web caching, HTTP header enrichment, firewalls, may greatly improve the user experience resulting in increased user loyalty, but may also be utilized to lower operational costs or to monetize the traffic by providing differentiated service handling. Typical deployments today simply chain all the service enablers for all mobile broadband traffic for provisioning VAS in the Mobile Service Zone. The service enablers are chained in a serial manner as shown in Fig. 1. Since all the mobile broadband traffic flows pass every service enabler, this model has the several deficiencies. It requires considerable effort to insert new service enablers or to upgrade existing ones. Every change of a single enabler may lead to a reconfiguration of all service enablers that are chained. A failure of a single enabler may interrupt the overall service. Each enabler has to process and forward all the traffic flows, which increases the overall processing, the traffic delay and also service costs. 1

PCRF BOSS TCP O&M Service Enablers Video Ad Insert WEB Others Internet User RAN PGW/GGSN Mobile Pipe Zone Mobile Service Zone Fig.1 Current mobile pipe zone and mobile service zone This paper introduces Huawei s Service Based Routing (SBR) solution that provides a flexible, scalable and future proof approach for the mobile service zone. The solution selectively steers traffic to the desired service enablers in the order determined by policies. Powerful policies are described using a multi-dimensional policy control model. The Huawei SBR solution offers two deployment options: Standalone SBR, which works separate from the mobile gateway (GGSN/PGW), Embedded SBR, which works as part of the mobile gateway (GGSN/PGW). Both deployment options can evolve smoothly to employ SDN means for traffic steering with enhanced flexibility and performance. The following describes the deployment options and their evolution towards an SDN based SBR. 2

2. Huawei s SBR Solution for Agile Service Chaining 2.1 Architecture Overview Huawei s SBR solution is based on Policy and Charging Enforcement Function (PCEF) or Traffic Detection Function (TDF). It is either embedded in the mobile gateway or provided as standalone equipment. The SBR consists of three parts, the SBR controller (SBR-C), the Traffic Classifier (TC) and the Traffic Steering (TS) functional modules. The SBR-C manages the service routing policies either configured locally or received dynamically from a PCRF. The TC classifies traffic flows using shallow or deep packet inspection and reports the results to the SBR-C. According to the service routing policy, the SBR-C binds the classified traffic to the associated service chain and indicates TS to forward the classified traffic selectively to the service enablers determined by the service routing policies. After processing the data traffic every service enabler sends the traffic back to the TS for the next forwarding, which bases on policies. The SBR-C also has the capability to monitor the running status (e.g., heath, load etc) of each service enabler for service enabler selection when executing load balancing in a service enabler pool. This approach, specifically using policies, provides an agile service chaining, which also avoids that all traffic flows have to pass all the service enablers. We estimate that the savings on TCO for service enablers can reach up to 60% for typical traffic patterns. PCRF Gx Gx/Sd The PCEF/TDF (SBR) is either embedded in the PGW/GGSN or provided as standalone equipment. PCEF/TDF (SBR) SBR Controller User A Cell1: Congestion Cell2: Normal Traffic Classifier Traffic Steering Internet User B GGSN/PGW LAN Switch TCP Video Ad Insert WEB Service Enablers Mobile Pipe Zone Mobile Service Zone Fig. 2 Huawei SBR architecture 3

2.2 Multi-Dimensional Policy Control The Huawei SBR provides operators with multi-dimensional service routing policy control, i.e. with best awareness option. These options are user awareness, radio access awareness, and service type awareness. The traffic can be steered through any service enabler in any possible order based on any combination of these awareness conditions. User awareness The SBR holds for every user a user context. The context comprises, amongst others, the user identity and the service routing policy. The service routing policy is decided according to the user subscription. So the service routing policy is associated with user profile. With the user specific service routing policy, the traffic can be classified into different user categories. For example, the video traffic of VIP user can be steered via a video optimizer service enabler, while the video traffic of regular user goes directly to the internet. Radio access awareness The SBR can also acquire other mobile network information such as radio access type and user location from mobile gateway or PCRF. Furthermore, if the mobile gateway is upgraded with new features, such as User Plane Congestion Management (UPCON), the SBR can obtain radio congestion status. With all this information the SBR can steer user traffic to service enablers depending on different network conditions. For example, when the user has a 3G connection, the video traffic is steered via a video optimizer for smooth video streaming under low bandwidth condition. When the user has a 4G connection, the video traffics needs no specific optimization and can be routed straight from the source to the user device. Service type awareness The SBR has the ability to identify the service type of a traffic flow by analyzing traffic from layer 3 to layer 7. The VAS policies can base on the service type determined by any of those criteria. For example, web traffic can be directed to the web cache enablers, while the video streaming traffic can be forwarded to the video optimization enabler. 4

2.3 Flexible Deployment Huawei s SBR solution offers operators flexible deployment choices: Embedded SBR deployment This choice is for operators who prefer to deploy a new PGW/GGSN or replace an old one. The embedded SBR solution provides flexible and efficient service routing policy control based on user context and radio access information directly available at the mobile gateway. Further this choice of a new PGW/GGSN with embedded SBR function simplifies the deployment and management efforts for service provision at mobile service zone. Standalone SBR deployment This choice is for operators who have deployed PGWs/GGSNs and prefer not to replace those. Here Huawei s SBR solution is deployed as standalone PCEF/TDF equipment. This PCEF/TDF is placed behind the Gi/SGi interface of the existing PGW/GGSN without any changes for the mobile pipe zone. The standalone SBR deployment leads to more policy control signaling and additional configuration than the embedded SBR. 5

3. Evolution to SDN based SBR The emerging Software Defined Networking (SDN) technology, decoupling control and data plane, provides operators with programmable switches and centralized controller to achieve highly flexibly and automatically networking. PCRF User A The PCEF/TDF (SBR) is either embedded in the PGW/GGSN or provided as standalone equipment. Cell1: Congestion Cell2: Normal GGSN/PGW Gx Gx/Sd PCEF/TDF (SBR) SBR Controller Traffic Classifier NB SDN SB Controller SB Cloud Service Enablers TCP Video Ad Insert SDN Switches / Fabric WEB Internet User B Mobile Pipe Zone Mobile Service Zone Fig. 3 Huawei SBR solution using SDN Huawei s PCEF/TDF based SBR can smoothly evolve to support SDN capabilities. As shown in Figure 3, the TS function is offloaded to the SDN enabled network and the SBR-C and TC part are left in the PCEF/TDF (SBR). The SBR using SDN solution contains three kinds of components: PCEF/TDF (SBR), SDN controller and SDN switch. The TC classifies traffic flows using shallow or deep packet inspection and reports the results to the SBR-C. According to the service routing policy, the SBR-C binds the classified traffic to the associated service chain. The SBR-C then indicates SDN controller (via southbound interface of SDN controller) to send L3/L4 forwarding rules (via northbound interface of SDN controller) to the programmable switches along the service chain path. These forwarding rules steer the classified traffic flows to the required service enablers in specific order as defined by the service chain. With SDN based SBR the traffic that traverse multiple service enablers does not have to go back to the PCEF/TDF (SBR) for traffic steering to the next service enabler, which optimizes the traffic going through the mobile service zone. On the other hand, when the SDN based SBR solution is deployed in Cloud-based virtualization environment, the SDN helps PCEF/TDF (SBR) to do virtual service enabler load balancing and scale-out/scale-in according to traffic load automatically, which is not an easy task in the Non-SDN approaches. 6

4. Benefits of Huawei SBR Solution In summary, Huawei SBR solution provides following benefits: Has minimal impact on existing investment by utilizing 3GPP standard PCC architecture Provides multi-dimensional policy control with mobile user identity awareness, radio access awareness as well as service type awareness. Eliminates need for over-dimensioning capacity of service enablers by its flexible service chaining. The TCO saving of service enablers can be achieved up to 60% for typical traffic pattern. Enables flexible deployment, embedded or standalone Ready for smooth evolution to SDN based SBR with enhanced flexibility and performance. 5. Conclusion A need for continued investment in value added services for the mobile service zone may be envisioned given the rate of traffic growth. Besides improving the resource usage of the mobile pipe zone deploying value added services can also provide new ways to monetize mobile network as well as improve mobile user experience. Today s common practice at mobile service zone lacks efficient service provision mechanisms that can provide agile service chaining. Huawei offers an SBR solution that provides a flexible, scalable and future proof approach for the mobile service zone. The solution selectively steers user data traffic to the required service enablers in the required specific order using a multi-dimensional policy control. Two deployment options (embedded SBR and standalone SBR) and the SDN evolution capability are offered to meet various operator requirements. The embedded SBR solution provides operator with low deployment efforts and most flexible policy control, while the standalone SBR can be deployed with minimal impact on the existing network. Both SBR solutions can smoothly evolve to use SDN method with enhanced flexibility and performance. 7

6. Annex: Abbreviation SBR EPC MME GGSN OTT PGW PCC PCEF TDF PCRF SGSN SDN TCO UPCON VAS Service Based Routing Evolved Packet Core Mobility Management Entity Gateway GPRS Support Node Over The Top PDN Gateway Policy Control and Charging Policy and Charging Enforcement Function Traffic Detection Function Policy and Charging Rules Function Serving GPRS Support Node Software Defined Network Total Cost of Ownership User Plane CONgestion management Value Added Service 8

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