This Industry Viewpoint was authored by Praveen Chalamalasetti, Vishwa Nigam, and Rakesh Roy at Prodapt.
VoD/CDN delivery ecosystem
Video on demand (VoD) continues to grow at an unprecedented rate as millions of users subscribe to digital on-demand video viewing experience globally. Cisco predicts that the IP video traffic will be 82 percent of the global consumer internet traffic by 2021, from 73 percent in 2016 and consumer VoD traffic will nearly double by 2021. However, digital service providers (DSPs) face a huge challenge in delivering high-quality viewing experience to customers with this multi-fold increase in consumption of on-demand video content and increased complexity. The content consumption pattern of consumers is changing rapidly. The expectation for the seamless delivery of on-demand content services across devices, with more inclination towards mobile devices, has increased significantly. DSPs rely heavily on their own CDN cache regions or interconnects with third-party ISPs. Congestion on these links can directly affect the customer experience. The challenges posed by such complex VoD/CDN delivery ecosystem in ensuring congestion-free traffic delivery are:
- Unpredictable service outages: Link failures, CDN region failures, hardware failures
- Inefficient utilization of capacity and resources
- VoD traffic congestion due to inefficient routing methodologies (e.g. manual CLI-based routing configurations)
DSPs need a sophisticated, real-time traffic management mechanism to deliver quality video viewing experience. An SDN-based traffic steering with central management plane is the ideal solution to handle these challenges. This article covers the key steps involved in the implementation of the SDN-based traffic steering model for VoD traffic handling.
- Implement SDN controller to enable centralized control plane with avendor-neutralnetwork abstraction
Implementing SDN Controller is the first step towards achieving centralized control and sophisticated traffic steering. However, customizations are required to address the below challenges in the SDN environment. Some of them are:
- Managing legacy switches/routers that do not support open interfaces
- Managing MPLS features like route positioning, conditional routing
OpenDaylight (ODL) SDN controller is used in this blog to highlight the solution approach. However, other leading SDN controllers like Juniper Contrail, Cisco WAE, Border 6 can also be used based on the business need.
Highlights of OpenDaylight (ODL) Controller:
ODL is an opensource, cost-effective and vendor agnostic controller that allows building custom applications within the controller itself. It also allows developing a traffic engineering application to manage both legacy MPLS network elements and SDN-ready elements.
- Develop a traffic engineering app to manage both legacy MPLS network elements and SDN-ready elements
Traffic Engineering (TE) App: TE app enables real-time, automated routing policy enforcement based on various business logic and network events from the central control plane. No more hassles of manual and cumbersome CLI-based routing configurations at each network element.
The TE app offers the following functionalities:
- Enables CLI-based adapter development for legacy MPLS network integration
- Enables interface/integration with northbound IT systems (O/BSS applications)
- Enables API development for specific business applications
- Enables traffic-handling features like policy-based routing and egress peer engineering implemented externally
TE app has two components that work together to provide above functionalities.
- Internal component: This is developed as a native OSGI bundle in ODL SDN controller readily using internal capabilities
- External component: It is independent of the SDN controller and enables business and network logics and API development
- Configuring automated and dynamic routing policies on TE application to achieve sophisticated traffic steering:
Once the customized TE app is built, all the needed sophisticated traffic steering policies can be configured on it and implemented on the central control plane.
- Policy-based Routing (PBR): PBR provides a flexible mechanism for forwarding data packets. TE app configures the access control lists (ACLs) to determine LSPs. The configured policies can selectively cause packets to take different/alternate paths.
- Segment Routing: Segment routing helps to specify a routing policy to multiple paths to steer labeled or IP traffic. The SDN controller allows the ingress router in a core network to steer traffic through explicit paths. The TE app enables SDN controller to automatically add an ordered list of segments associated with the policy to the header of a data packet. This enables automated traffic steering, based on network or business requirement.
- Egress Peer Engineering: The controller instructs an ingress router in a domain to direct traffic towards a specific egress router using a specific external interface. It then defines a template with paths on egress BGP peers to enable MPLS fast reroute. The TE app then configures automated IP forwarding on the boundary routers for policy-based traffic steering (QoS, time-of-day etc.)
- Improved service availability and enhanced customer video experience with automated and sophisticated traffic steering
- Reduced operational overhead and increase in operational efficiency with multi-vendor network abstraction and centralized routing control
- Automated traffic steering enables utilization of latent link capacity in real time to facilitate improved resource utilization
Praveen Chalamalasetti, Technical Lead- SDN Labs, Prodapt
Vishwa Nigam, Manager Strategic Insights and Thought Leadership, Prodapt
Rakesh Roy, Senior Solution Architect, SDN/ NFV, Prodapt