Software-Defined Networking( SDN) promises to add value and greatly improve the way IP routers and optical transports are currently managed.

High-level SDN controller languages made accessible via an emerging AT&T User-Defined Network Cloud (built on top of the AT&T Domain 2.0 network architecture) are putting customers at the center of the network with a modern, cloud-based architecture that runs on a global scale. That capability is expected to significantly reduce the time required to bring technologically-advanced products and services to market.

photo of cloud networkThe AT&T User-Defined Network Cloud will simplify configuration, ease the introduction of nimble policy control, reduce errors, and enable more real-time changes in a packet/optical network. Controller-to-packet switch interface standards like OpenFlow and NETCONF, for example, will make it easier not only to manage and maintain networks, but also to incrementally introduce improvements in a non-disruptive manner, because there will be far fewer hardware dependencies.

Virtualization technology enables opportunity

A new generation of Network Function Virtualization (NFV) infrastructure must be in place to enable these AT&T User-Defined Network Cloud capabilities. NFV infrastructure allows network functions to be turned into software, called virtual network functions (VNFs). This represents either a one-for-one mapping of an existing appliance function or, in the future, a combination of new and existing network functions.

At its core, NFV makes use of virtualization technology to consolidate many network equipment types onto industry-standard high-volume servers, switches, and storage that can be located in any data centers, network points of presence (PoPs), or customer premise.

VNFs will also distribute data services in a way that not only eliminates tiers of appliances, but also satisfies fault-tolerant or one-for-one failover spare appliance hardware requirements. This ability to reduce equipment diversity and power consumption through consolidating equipment creates a unique opportunity to simultaneously cut costs while increasing the flexibility of the AT&T User-Defined Network Cloud environment.

Meeting challenges with orchestration software

To turn that vision into reality, the first challenge is developing new applications that support existing monolithic control plane elements, such as route reflectors, DNS servers, and DHCP servers.

Over time, a broad range of network edge and middle box functions are expected to migrate to NFV infrastructure, including SAE gateways, broadband network gateways, IP edge routers for services like IP-VPN and Ethernet, and load balancers and distributors. Because these elements don’t typically need to forward large aggregates of traffic, their workloads can be distributed across a number of servers, adding an elastic capability that is unattainable in a monolithic model.

A critical component of the AT&T User-Defined Network Cloud is the orchestration software used to manage the overall environment. Similar to what we see today in cloud computing services, orchestration software will enable organizations to create catalogs of functions that can be instantiated any number of times. In addition, it will allow users to dynamically compose various network functions to expose SDN capabilities via open application programming interfaces.

The high cost of hardware: investment and operation

Like every other network, the AT&T networking environment is composed of a large number of proprietary hardware appliances. Launching a new network service often requires adding yet another variety of hardware. In addition to the capital expense required, the space and power these hardware appliances consume represents a significant operating expense.

These challenges are further compounded by the increasing costs of energy and the scarcity of the skills needed to design, integrate, and operate increasingly complex hardware-based appliances. Moreover, appliances rapidly reach end-of-life, which leads to a procure-design-integrate-deploy cycle that has to be continuously repeated with little or no revenue benefit.

Taken together, all these issues serve to constrain innovation and inhibit the expeditious rollout of new network services.

Exploring the promise of visualization

SDN and NFV technologies make it possible to envision changes in basic system architecture without having to dump and re-deploy infrastructure and the associated capital investment. Because the essence of networking is now provided through software, it becomes possible to use the same supporting infrastructure to simultaneously deploy multiple network architectures.

For these reasons, we believe that VNFs will rapidly become the “killer app” of AT&T User-Defined Network Cloud.