April  2000

Application-Optimized Networking: A Case Study

BY TONY RYBCZYNSKI

THE EARLY DAYS
In the 70s, AFC�s network was legion: multiple disparate networks including its telephony network and of a mix of vendor -- and application-specific data networks centered around mainframes or distributed minicomputers. The end devices were dumb terminals. Each network was individually designed to minimize the cost of delivering certain performance and reliability levels, and ran over a common channelized T1 multiplexor network.

In the 80s and early 90s, the network moved toward PCs and client/server, LAN-based infrastructures. While mission-critical transaction-based applications ran on IBM�s SNA and token ring LANs, other business unit-driven applications used multiple protocols run over bridged and routed LANs deployed in a relatively decentralized fashion. In order to improve WAN price/performance and reliability, AFC leveraged highly reliable Layer 2 enterprise network switch technologies, integrating all its traffic over a dynamic bandwidth ATM and frame relay network at the backbone and branch levels respectively.

THE MID 90s
The mid 90s saw four major events: the strategic importance of IP, the emergence of Ethernet switching, Y2K, and the emergence of the Web. AFC made a decision to converge on IP as the standard networking protocol, and as the platform for new applications. Moving towards IP simplified its networking environment and allowed AFC to leverage IP industry developments. AFC also decided to standardize on Ethernet switching at the desktop, enhancing manageability and price/performance. The campus backbone was built on FDDI and ATM, both viewed as highly reliable architectures. All IP-based applications were treated equally and continued to be handled on a best effort basis. As mainframe applications were either encapsulated onto IP or displaced by client server solutions, more comprehensive IP network engineering was required to meet performance requirements.

THE LATE 90s
While internal growth was one of the major factors driving AFC�s IP network during the last decade, a critically important new factor has emerged. Initially, AFC provided consumer-to-business and business-to-business self-serve product information via the Web. Today, AFC supports transactional capabilities. AFC also runs a sophisticated call center, which today is being operated totally independently of its Web services. AFC is just starting to roll out an integrated CRM system, with the intent of allowing unified customer interaction across the full range of contact channels.

These Internet-driven e-business capabilities not only impose requirements at the edge of the Internet, but also across the entire inter-site network. AFC is going with best-in-class open IP solutions: high performance networking for back-office applications and access to databases, and application servers and customer-facing employees distributed across the enterprise. With the large-scale deployment of IP-based applications and services across its network and out across the Internet, AFC has evolved its IP network to offer better security, more predictability, increased reliability, and better price/performance.

Reliable Layer 3 routing switches supporting multilink 100/1000 Mbps trunking were deployed in the campus networks, replacing ATM- and FDDI-based solutions. This eased networking engineering and design, minimized fault isolation times, and enhanced network reliability. In the inter-site WAN, AFC continued to use of Layer 2 capabilities to provide better resilience and traffic management. At the edge of the Internet, AFC deployed a complex of application servers, routers, switches, and security devices.

Since AFC was pushing the envelope, it had to do its own integration and deploy multiple boxes for redundancy. AFC also made use of unified network management tools to monitor network status and facilitate rapid fault isolation across multivendor network environments via SNMP, though these capabilities were much more comprehensive over the inter-site network than at the Internet edge.

AFC started to make use of Class of Service (CoS) mechanisms based on the IETF DiffServ architecture to ensure performance requirements were met under any conditions. Given that CoS configuration was relatively resource intensive, AFC�s strategy was to deploy CoS at network hot spots (e.g., across the WAN), while continuing to use best effort networking over relatively bandwidth-rich LANs. AFC redesigned its IP network to meet the reliability and latency requirements by ensuring a maximum of two hops between any two backbone sites with redundancy. This eased the introduction of CoS.

Growth on the network has been dramatic. IP traffic is growing at a run-rate of 100 percent per year, driven by hundreds of internal Web servers as well as by Internet traffic. There is also substantial telephony, room-to-room video conferencing, and legacy traffic. AFC�s network supports the business 24 hours per day, seven days per week.

THE NEW FRONTIER
AFC�s enterprise IP network is now central to how AFC conducts marketing, sales, and service in a highly distributed environment. But the rate of change is increasing as the Web moves towards real-time collaboration with customers and with an ever more distributed workforce. AFC sees IP telephony as a key enabling technology. To implement it and to provide an architected CoS and security infrastructure, AFC is deploying comprehensive management policies that define how network resources are allocated across devices, end users, and applications.

While handling IP CoS reliably across leased lines is under the control of the enterprise, doing the same over virtual leased lines is somewhat more problematic. AFC maintains a high degree of flexibility at the WAN edge to extend multiservice IP network reliability and performance across these carrier environments on a global basis.

AFC sees security as a critical dimension of policy management, coupled with on-switch functionality and �off-network� security management. This is not only driven by e-business. Remote access Internet VPNs have been standardized within AFC, replacing its own remote access switches for telecommuters and road warriors. AFC�s network is also being opened up to partners and suppliers as a business necessity. Inter-site Internet IP VPNs are also being considered for some remote sites.

LESSONS LEARNED
AFC has learned that taking an application perspective is key in the development of a multiservice IP network. It therefore will commit via service level agreements to securely, consistently, and reliably meet connectivity, latency, and throughput requirements for business-critical applications and end users.

Service level management includes capabilities to monitor network availability, transaction times, and throughput, all as seen by the end user application. This requires a small client resident in the end user PC that recognizes most common applications and monitors how the network is performing for these applications. AFC has therefore adopted a �closed loop� policy management approach that includes configuration of edge devices, enforcement of policies in the network, and verification of performance as seen by the end user application.

Tony Rybczynski is director of strategic marketing and technologies for Nortel Networks� Enterprise Solutions unit. For more information, visit the company�s Web site at nortelnetworks.com. E-mail comments to [email protected].