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Feature Article
June 2003

Tony Rybczynski photoMaking Business Realities Work For You

Part VI: Why �best effort� isn�t the best for your enterprise network.



Business Reality: The rules of the game have changed.

For at least three years, our economy has been on a wild ride that has challenged all notions about �business as usual.� Global network connectivity increased corporate reach and revenues, but also blurred the lines between internal and external resources, between trusted and insecure, private and virtually private. The communications advancements that spawned new opportunities for collaboration also accelerated the pace of change and ratcheted up every baseline expectation for productivity and turnaround. The eCommerce applications that generated gigabytes of data at every phase of the process also drowned the systems that were supposed to capture, digest, and share them. The proliferation of new contact channels produced disconnects that led customers to wonder if they were in fact dealing with one company.

These realities highlight the urgent need to increase IT agility in serving business objectives, and to implement a networking infrastructure that can meet evolving application demands.

When �Best Effort� Isn�t Good Enough
Traditional IP networks were built on hubs, bridges, and routers with limited or no redundancy. End-to-end reliability was achieved through a combination of dynamic routing and application-level TCP error recovery. IP networks offered best-effort networking only, relying on IT�s ability to stay ahead of the traffic growth curve.

The challenge is to create IP networks that support a full spectrum of business application needs, including transactional, interactive, and collaborative services and file transfers. However, meeting application needs goes beyond nodal reliability and quality of service (QoS) considerations, as is illustrated by these real-world examples:

� Routing protocol hop count limits can result in logical disconnects that result in a user not �seeing� a network resource such as a printer. In such a case, the network may be 100 percent up, and the application 100 percent down.

� Network congestion can increase packet loss, which in turn impacts audio and video streaming and IP telephony applications. IP telephony users may have to hang up the call and try again.

� Back-end processing delays may prompt customers to abandon Web transactions and visit competitive Web sites instead.

� Excessive file transfer delays could conflict with financial book closing intervals or customer contractual commitments.

� Users may get sluggish server response, while other servers that support the same application are underutilized.

� High participation in a Webcast can degrade performance to all users due to network congestion.

Taking months to redesign the network to accommodate a new application that will deliver competitive advantage is the wrong answer in today�s world.

Most enterprises recognize the need to evolve their networks from a best-effort IP world. Some will respond by according special treatment to selected applications, such as customer care, transaction services, or IP telephony. Others will run the network as an internal service or utility, offering a range of service level agreements (SLAs) to their business units. Whatever the strategy, the foundation is to adopt an application-oriented view of end-to-end network performance, rather than a network-oriented view.

Technology Response: Instead of �best-effort,� think �content-aware intelligence.�
When building and designing enterprise networks, the IT organization must foster an application-oriented view. Application-optimized networks:

� Provide the agility to support diverse data, voice, and video applications;

� Eliminate network bottlenecks that inhibit introduction of new applications;

� Consistently and reliably deliver required levels of connectivity, latency and throughput; and

� Embrace data centers, server farms, and databases, as well as communications links among them.

Let�s take a look at some key considerations:

Rapid recovery. Real-time, delay-intolerant applications such as IP telephony and interactive collaboration require rapid recovery from equipment and physical link failures. At the nodal level, key core elements must be engineered for redundancy and rapid recovery. Simplified network architectures (fewer tiers and fewer boxes) using Layer 2/3 switching ease networking engineering and design, while minimizing fault isolation and recovery times. For example, multi-link trunking and resilient packet rings provide highly reliable Ethernet networking.

Quality of service. Even when bandwidth is over-engineered, QoS mechanisms are required to ensure performance requirements are met under normal, congested, and failure conditions. Very low latency across network switches and a manageable number of user traffic categories across the network can support various classes, such as real-time, delay-intolerant (premium); real-time, delay tolerant (platinum, gold); non-real-time, mission-critical (silver, bronze); and non-real-time non-mission critical (standard). QoS classification functionality should be implemented as close to the application as possible, ideally in the application itself.

Policy management. �Closed loop� policy management ensures that QoS and security policies are consistently applied across the network, and includes configuration of edge devices, enforcement of policies in the network, and verification of performance and security controls in line with corporate policies. Enforcement of policies in the network also includes admission controls of applications vying for access to network and application resources.

Reconsidering The Network Edge, Core, And Operations Center
Extending application-optimized enterprise network performance and reliability across service provider networks requires a high degree of flexibility at the enterprise edge. QoS has to be mapped to the appropriate service provider protocol mechanisms, while optimizing price/performance. Reliability options include Layer 1, 2, and 3 mechanisms such as SONET and DWDM redundancy, ATM multilink, IP dual homing, and ISDN backup. Rapid detection of access and service failures on IP, frame relay, and ATM are also a necessity. Emerging optical Ethernet MAN/WAN networking eliminates many of the barriers to end-to-end application-optimized networking, by establishing a reliable consistent Ethernet-based networking infrastructure.

Finally, on the networking front, more rigorous operational and engineering procedures within the enterprise need to be adopted, recognizing the transition from best-effort networking to always-on, application-optimized networking.

These considerations apply across the enterprise network -- and to the data centers, server farms, and databases that fuel business-critical applications. Here�s where Layer 4-7 networking comes in -- extending intelligent security and networking technologies across entire application infrastructure to enhance reliability and performance.

The Role Of Layer 4-7 Networking In The Application-Optimized Network
Layer 1-3 routers make decisions based on physical, link, and network-level information -- which port, which interface, which IP address. That�s fine and well for best-effort routing, but the new Business Realities call for the advantages of Layer 4-7 traffic management and application switching.

Layer 4-7 application switches and networking devices know link and network information, just as Layer 1-3 devices do, but they also know application-level information, such as what type of user or device is requesting the content (handheld device, frequent shopper, first-time visitor, etc.), what type of content the user is requesting (executable script, static content, streaming Web cast, shopping cart, etc.), and more. These capabilities reduce global network load and costs, improve server and network response time, and enable differentiated services that cannot be achieved any other way.

Application switches and intelligent networking devices support a number of advanced services, such as:

� Intelligent load balancing across severs, firewalls, and many other devices, and content-intelligent application redirection, based on full Layer-7 inspection of URLs and cookies.

� Content-aware security that protects servers and applications against attacks and unwanted intrusion and SSL (Secure Socket Layer) acceleration, relieving servers of the processing-intensive tasks associated with encryption.

� Intelligent bandwidth management capabilities that can meter, control, and account for resource utilization by any Layer 2-7 attribute, including client, server farm, filters, service, application, user class, URL, cookies, and content type.

� Content caching capabilities, that cache frequently used content close to requesting users and apply other �smart� storage strategies to deliver content in a bandwidth-efficient fashion.

Purpose-built networking platforms, selectively operating across Layers 1-7, including integrated routing, are starting to replace legacy multi-protocol routers as the workhorse of enterprise networks. Application-optimized networking, include content-aware intelligence, deliver the functionality required to win, now that the rules of the game have irrevocably changed.

Tony Rybczynski is director of strategic enterprise technologies for Nortel Networks with 30 years experience in networking. For more information, visit the company�s Web site at www.nortelnetworks.com.

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