The Cisco Learning Network lists the areas that you will be tested on. The candidate should familiarize themselves with those. The things that I feel you need to have a firm grasp on are varied. The biggest trouble spot for people is the way in which Cisco words their questions. Anyone that has taken a Cisco test will recognize the style of questions, and you should be able to narrow down the possible answers if you have studied well enough. Again you should not be surprised by any questions you are asked. I have taken about 20 Cisco exams over the years, and I still get confused by the way questions are presented. The way to overcome this is to know the information they will possibly test you on very well.
As with any test, your preparation will decide success or failure. The first thing you will need to do is develop a study plan for this exam; a good method is to start by dividing the topics into sections. Knowing your subject is the most important and is crucial to success. The commands that are associated with CVOICE 8.0 should be practiced over and over until you can recognize any discrepancies on the exam that will help you isolate the correct answer. The next thing that will help is to practice setting up a CUCME from scratch a few times. This knowledge will prove vital during the exam. Dial-peers are another thing you should practice; try creating enough dial-peers that you are tired of creating them. Once you have mastered dial-peers, move on to e-phones. Practice configuring a few e-phones and their options.
QoS is another area you should be very familiar with. The QoS implemented on Cisco devices hasn’t changed in a long time. Cisco use to have an entire test on QoS, so count yourself lucky you’re not taking the old exam. However, you will need to study all resources that will assist you mastering QoS. The QoS on the exam must not be taken lightly, as there will probably be a good number of questions about it within the test. When learning QoS, you need to find ways to memorize the exact commands; the choices you will have will look very similar. Another area you will need to know is the various QoS methods and how the function. Areas that should be studied are the main QoS methods and when they should be used, and how to implement them. This goes back to the point earlier that you will need to know topics well.
Dial plans are a huge part of the CVOICE 8 exam. The area is vast and requires a good study approach. Questions about dial plans can cover a range of areas, including permissions, dial-peers, translation patterns, etc. the areas of concern will most likely be translations. You should be able to decrypt translation in CLI. The process of how gateways handle inbound and outbound calls should be second nature. Another aspect of dial plans will be the steps required to complete calls according to the requirements. You should be able to do this on any device, CUCME, CUBE, and Gateways. It would be safe to assume that there will be quite a few questions dealing with dial plan components.
Codecs are also a subject that can be tested on the exam. It would be in your best interest to learn the formula for calculating the number of calls that can be sent across links, depending on the codec, link speed and other options. The formula should be practiced until you are good with these calculations. The information you use for this should give you a good foundation to deal with any codec questions.
Signaling is a required knowledge for the exam. You should be able to explain how signaling between different components work. The exam might ask you to what signaling you should use in certain areas of a network. The signaling can deal with T1 circuits, PBX, and gateways.
VLAN questions can be included on your exam. This area should come easily; make sure you have a firm grasp on the concept and how to configure them.
Cisco Unified Communications Express, as one might expect, is also a major test area. The knowledge required here should include the commands to fully setup the CUCME. If you know the commands needed to make the CUCME fully functional, you’re ahead of the curve. The candidate will be tested on interactions with other devices within the network, depending on the functions being provided. One area you will need to know when dealing with CUCME is how the phones operate and their configurations. You should be able to analyze portions of the running configuration and resolve missing commands.