Product Documentation

Solutions for Telecom Service Providers

May 13, 2016

Information and Communication Technology (ICT) is about bringing the Internet user closer to the apps and data. The latest datacenter technologies have enabled the user, apps and data to be located anywhere. A user can access apps and data from the office or from home, or from a location such as an airport. The apps and data can be located either on the enterprise's premises, in a public or private cloud, or on a hybrid host. The result has been on only increased productivity, but also reduced costs of ownership and maintenance.

Service provides offer the core infrastructure needed for carrying the user's apps and data over the network. Because the core infrastructure serves millions of subscribers and a wide variety of apps and data, requirements for scale and protocol support are very high. The core infrastructure handles two major types of traffic: data plane and control plane. Each of these planes has its own scale and protocol-support requirements.

The data plane is the part of the core infrastructure that carries user apps and data from end to end, that is, between end-user equipment and the application server. The number of users accessing apps and data is in the thousands of millions, so throughput and IP-addressing requirements are very high. Every user in the network must be uniquely identifiable. Only then can the service provider control the traffic, monitor network usage, deliver user-specific services, and log information correctly. Many of the today's client devices and application servers support IPv6 natively. The core infrastructure must not only support a mix of IPv4 and IPv6 clients and servers, but also provide the technologies for cross-communication between IPv4 and IPv6. Finally, a service provider is measured by the quality of service (directly related to end-user experience) and the availability of service without disruptions. The data plane should be resilient enough to provide both quality and availability at the same time.

The control-plane infrastructure manages user traffic and maintains the business and network operations services. The most important of the many protocols that run in this plane are Diameter, Radius, and SMPP. Diameter is a base protocol over which several other function-specific protocols have been developed. For example:

  • Gx interface between the Policy and Charging Enforcement Function (PCEF) and the Policy and Charging Rules Function (PCRF)
  • Gy interface between the Online Charging System (OCS) and the Cisco Packet Data Network Gateway (PGW)/Policy and Charging Enforcement Function (PCEF)

The volume of control plane traffic is in direct proportion to user activity. To manage the control plane traffic, service providers use several ADC functionalities, such as load balancing and content switching. They need fine-grain control of control plane traffic, which equals data-plane traffic in complexity.

Service providers must meet demanding service-level agreements (SLAs), and are scrutinized thoroughly by regulators for compliance. Adhering to requirements while managing the data and control plane traffic requires a service provider to keep its infrastructure nimble, within budget, easily upgradable, and flexible. As the most powerful and advanced ADCs in the market today, Citrix NetScaler products are a natural fit for the service-provider environment.