Читать книгу CCNP Enterprise Certification Study Guide: Implementing and Operating Cisco Enterprise Network Core Technologies - Ben Piper, David Higby Clinton - Страница 24

THE CCNP ENCOR EXAM OBJECTIVES COVERED IN THIS CHAPTER INCLUDE THE FOLLOWING:

 Domain 1.0: Architecture✓ 1.1 Explain the different design principles used in an enterprise network✓ 1.7 Differentiate hardware and software switching mechanisms

 Domain 3.0: Infrastructure✓ 3.1 Layer 2✓ 3.2 Layer 3

Forgetting the fundamentals is by far the biggest cause of failures—both network failures and failing Cisco exams. Just visit any networking forum and look at the posts from people who failed an exam by a narrow margin. Almost without exception, they can trace back their failure to misunderstanding or simply failing to learn fundamental networking concepts.

Networking fundamentals can at times seem abstract and even impractical. It's important to remember that networks are both logical and physical, so you need to keep a tight grip on both. If you neglect theory and just focus on typing in commands, you'll end up with a jalopy network. It might work, but not very well, and probably not for long. On the other hand, learning theory that you fail to put into practice leads to being educated but unemployed.

This chapter will give you a solid theoretical foundation on which to build practical skills. Much of the theory should already be familiar to you, and you'll likely have some “I already know this stuff” moments. But more often than not you'll gain new insights on something you already understood.

There's a lot of networking information out there, much of which is poorly explained, if not just plain wrong. Networking myths abound on forums, blogs, and even Wikipedia. Even official Cisco documentation has been known to contain the occasional errata. It's not intentional, of course. Learning networking is no different than learning any other complex topic. Some concepts are easy, whereas others just never quite click. Those harder concepts are fertile breeding ground for misconceptions that eventually get passed around until they become common knowledge, or worse, “best practices.” Almost every network professional I've encountered holds at least one glaring misconception about networking that eventually ends up stumping them (sometimes on an exam!). Chances are you, too, have been the unfortunate recipient of such information. The sooner we identify and dispel those myths, the better. That's what this chapter is all about.