Network Edge Traffic Steering: IP Services

FIGURE 1-6 shows an overview of the various IP services that can be used in creating a multi-tier data center network architecture. These services are essentially packet processing functions that alter the flow of traffic from client to server for increasing certain aspects of the architecture. Firewalls and Secure Sockets Layer (SSL) are added for increasing security. Server load balancing (SLB) is used to increase availability, scalability, flexibility, and performance. In Chapter 4, we describe key services that the architect can leverage, including in-depth explanations of how they work and which variant is the best and why. A question that is often asked is which server load balancing algorithm is best and why. We provide a detailed technical analysis explaining exactly why one algorithm is the best. We also provide detailed explanation of the new emerging quality of service (QoS), which has gained more importance because of increasing deployment time-dependent applications, such as Voice over IP (VoIP) or multimedia.

Figure 1-6. Data Center Edge IP Services

Most enterprise networks are overprovisioned. Normal steady-state network flows are usually not an issue. What really concerns most competent network architects is how to handle peaks or bursts. Every potential incoming HTTP request could be a revenue-producing opportunity that cannot be discarded. Here is where QoS plays an essential role. One of the missing pieces in most network architectures is planning for handling peak workloads and providing differentiated services. When there is congestion, we absolutely must prioritize and service the important customers ahead of casual browsing Web surfers. Quality of service will be discussed in detail: its importance, where to use it, and how it works.