Changes in Enterprise Networks
Enterprise networks at many corporations have been undergoing major changes. The value of making vast amounts of data available to employees, customers, and business partners has been recognized. Corporate employees, field employees, contract employees, and telecommuters need access to sales, marketing, engineering, and financial data, regardless of whether the data is stored on centralized or distributed servers or mainframes. Suppliers, vendors, and customers also need access to many types of data.
A network that is used by only internal users is no longer the norm at many companies. Companies are seeking ways to build networks that more closely resemble modern organizations. Many modern organizations are based on an open, collaborative environment that provides access to information and services for many different constituents, including customers, prospective customers, vendors, suppliers, and employees. Cisco Systems uses the term network organizational model to define a network model that mirrors modern organizations that have expanded from traditional boundaries to include access for various constituents.
To remain competitive, companies need ways to reduce product development time and take advantage of just-in-time manufacturing principles. A lot of companies achieve these goals by partnering with suppliers and by fostering an online, interactive relationship with their suppliers. An example is automobile manufacturing. Instead of producing every automobile component in-house, many manufacturers contract with partners who specialize in specific components and technologies. For example, one partner might produce the engine while another produces the body. If all the partners can access data and services on the manufacturer's network, production costs are reduced, just-in-time manufacturing can be accomplished, and it is easier to plan around component shortages. The ability to share information saves time and money for the automobile manufacturer and for its partners.
A network designer must consider requirements to extend the network to outside users very carefully. For security reasons, external access should not mean full network access. Using a modular approach to network design is important here so that there is a clear boundary between the enterprise's private networks and the portions of the internetwork that partners can access.
Networks Must Make Business Sense
With the economic downturn that followed the Internet boom, there is an increased need to choose technologies that solve business problems. Although many companies made "technology for technology's sake" choices during the boom, this is no longer the case. Business leaders are more involved in Information Technology (IT) decisions than they once were, and IT managers rely on business managers to help them prioritize and fund IT projects. Network upgrades are made not because some new technology sounds interesting to the engineers, but because it will help an enterprise increase profits, productivity, market share, and cash flow. Network designers must choose solutions that solve a business manager's problem.
Network applications have become mission critical. Despite this trend, large budgets for networking and telecommunications operations have been reduced at some companies. Many companies have gone through difficult reengineering projects to reduce operational costs, and are still looking for ways to manage networks with fewer people and reduce the recurring costs of WAN circuits.
As the head count at many corporations remains flat or shrinks, there's a renewed focus on using network applications to increase individual productivity in all departments, not just within the networking and IT departments. One result has been the emergence of web-based productivity tools. Most enterprises streamline their business processes, applications, and protocols, and standardize on Transmission Control Protocol/Internet Protocol (TCP/IP). TCP/IP and web-based applications for selling products and supporting customers have risen in popularity, as have web-based applications for supporting employees and suppliers.
Streamlining processes and protocols has also led to an increased use of IP telephony and to the continued convergence of voice and data networks. To save money and to reduce the need for specialized data or voice engineers, companies continue to adopt IP telephony technologies.
Until recently, telecommunications and voice networks were separate.
Telecommunications engineers knew little about data networks, and networking engineers didn't know the difference between a TDM and a Tandem Switching System (TSS). In today's environment, voice, data, and video networks are merging.
In traditional voice and data terminal/mainframe networks, data flow and throughput were predictable. Closed communications systems were the norm, and data sources were well known. In today's networks, Internet surfing is ubiquitous. It is hard to predict data flow and the timing of bursts of data when users are jumping from one website to another, possibly downloading videos or animation files. In addition to web surfing, the move to a network organizational model where the network is used by both inside and outside users affects network data flow. Network design practices must keep pace with these changes in business practices.
The Need to Support Mobile Users
Notebook computers have finally become small enough to carry around, and workers now expect to get work done at home, on the train, in hotels, in meeting rooms, at customer sites, and even while having their morning latte at the local coffee shop. These days almost every notebook computer ships with wireless networking built in to facilitate users getting work done outside the office.
It shouldn't matter (to the user anyway) where data is and in what format. Network users expect network performance to be uniform, regardless of where the user or data resides. A user should be able to read e-mail on a cell phone, for example, and read voice mail from a web browser while sipping coffee in an Internet cafe. Users should have secure and reliable access to tools and data wherever they are. The challenge for network designers is to build networks that allow data to travel in and out of the enterprise network from various wired and wireless portals without picking up any viruses and without being read by parties for whom it was not intended.
One of the biggest trends in network design is virtual private networking, where private networks make use of public service networks to get to remote locations or possibly other organizations. Customers getting involved in VPN projects have concerns about security, reliable and predictable performance, and data throughput requirements. VPNs are covered in Chapter 5, "Designing a Network Topology."
Network architectures are taking on a virtual and ubiquitous form for users, while remaining highly structured and managed from the network engineers' point of view. The designer is challenged to develop secure, resilient, and manageable solutions that allow users to work efficiently, wherever they are physically located.
The Importance of Network Security and Resiliency
Network security has filtered to the top of the list of business goals at many companies. Although security was always important, it has become even more important as networks become indispensable and as tools for breaking into networks become ubiquitous. Enterprises must protect their networks from both the unsophisticated "script kiddies" and from more advanced attacks launched by criminals or political enemies. There is also a continued requirement to protect networks from Trojan horses and viruses.
Many enterprise managers now report that the network must be available 99.999 percent of the time. Although this goal may not be achievable without expensive redundancy in staff and equipment, it may be a reasonable goal for companies that would experience a severe loss of revenue or credibility if the network were down for even very short periods of time. This goal is linked to goals for security, as the network can't be available if security breaches and viruses are disabling network devices and applications. When security and operational problems occur, networks must recover quickly. Networks must be resilient. More than ever, IT and business managers require high-availability and resiliency features for their network equipment and protocols, as they realize the extent to which network downtime can jeopardize business success.
In addition to security, another goal that has filtered to the top of the list of business goals is the need for business continuity during and after a disaster. Companies have learned from the attacks on the World Trade Center on September 11th, 2001, the importance of resiliency for network designs and applications. Many companies, including Lehman Brothers and the Wall Street Journal, managed to resume operations immediately following the attack. They were able to continue business operations because of a well-planned disaster recovery strategy and because of the redundancy built in to their networks.
Companies that have survived hurricanes, earthquakes, and fires have also learned the importance of a disaster recovery plan that promotes business continuity, despite the loss of critical network devices and services. Many companies have not had the misfortune of learning these lessons the hard way, but are nonetheless embarking on network design projects with the goal of developing a network that will recover quickly in the event of a natural or unnatural disaster.
One aspect of analyzing a customer's business goals is the process of analyzing vulnerabilities related to disasters and the impact on business operations. Help your customer determine which network capabilities are critical and which facilities provide them. Consider how much of the network could be damaged without completely disrupting the company's mission. Determine whether other locations in the company are prepared to take on mission-critical functions.
In the last few years, networks have become more interconnected and complex, which can make meeting goals for network resiliency more difficult. Many enterprise networks are linked to telecommuter home networks, branch-office networks, extranets that offer access to business partners and customers, and the Internet. The diversity and quantity of portals into the enterprise network pose many security and stability risks. On the other hand, geographical diversity of mission-critical capabilities has turned out to be a lifesaver for some companies hit with disaster. One reason that the Wall Street Journal was able to publish its newspaper the day after the 9/11 attacks was because it had learned from 1990 power outages about the need to disperse critical functions across many different sites.
These days, security and disaster recovery should be considered with every network design choice, and the network designer must propose solutions that provide resiliency and stability. A systematic and modular design process, as taught in this book, is even more important than it once was, as networks become increasingly complex and vital to an organization's success.
Continue reading here: Identifying the Scope of a Network Design Project
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