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8
Establishing an X.25 Connection
The CCNP Remote Access Exam requires you to be familiar with the implementation
options associated with X.25. You must understand the basic deployment of X.25 as well
as the optional configuration parameters.
X.25 is similar in some respects to ISDN. The basic functionality of the two is based on the
same technology, and the Public Switched Telephone Network (PSTN) still provides the
necessary switching facilities. X.25 is similar not only to ISDN for switched virtual circuits
(SVCs) but also to Frame Relay. In addition, the frame format is almost identical to High-
Level Data Link Control (HDLC). It is imperative that you understand the relationship
between DCE and DTE devices. The relationship is discussed throughout the chapter.
The exam requires an understanding of various deployment configuration options,
including window sizes, packet sizes, and communications windows.
How to Best Use This Chapter
By taking the following steps, you can make better use of your study time:
·
Keep your notes and answers for all your work with this book in one place for easy
reference.
·
Take the "Do I Know This Already?" quiz and write down your answers. Studies show
retention is significantly increased through writing facts and concepts down, even if
you never look at the information again.
·
Use the diagram in Figure 8-1 to guide you to the next step.