WAN design. Although analyzing the amount of traffic crossing the WAN and dissecting the
WAN's routing protocols are important, your first analysis should be an understanding of the
business objectives. Customers know that if a network is cost-effective, reliable, and available,
it will help them meet their bottom-line goals. For businesses that have profit as an objective,
the network must help them achieve their goal of profitability. Nonprofit organizations will
want the network to help them be more productive.
implemented and accepted within the organization. Understanding an organization's politics is
important. In a perfect-world vacuum, the best technical solution would always be accepted.
More often than not, the rendered real-world solution reflects a compromise between the
technical, political, and organizational dynamics of the day. As an example, an organization
might have policies regarding vendors, platforms, and technologies. For example, your favorite
vendor and first choice, RouteitRight, might not be on the list of approved vendors. The CCDP
must be prepared to address real-world constraints when rendering the original design concept.
As soon as a customer's business objectives are understood, the CCDP should pursue the
customer's technical objectives for a WAN design.
design themes of availability, scalability, reliability, and cost still apply, the CCDP who designs
the WAN will find that they have less control over some of the WAN design variables.
LAN design. As an example, latency plays a more important factor in WAN design. Because
WAN bandwidth is typically slower than a LAN, a WAN and the traffic that travels on it are
more sensitive to issues of latency. Cost plays a larger factor in WAN design than LAN design.
The recurring monthly costs of the WAN do not exist in LAN design.
backbone, impacts so many people. To add to the drama, much of the WAN's reliability and
availability lie beyond the control of the CCDP and within the control of the vendor. Vendors
in different geographical areas provide different capabilities. Issues that impact the last mile
will vary from location to location. Nevertheless, certain areas of the WAN core can be
controlled. This chapter discusses the tools and methods available to the CCDP to optimize the
WAN for maximum reliability and availability.