0.1%
1%
2.5%
25%
第1题：
【A popular service that has attercted the interest of companies and has home users alike is the sending of voice signals over an IP-based network, such as the Internet. The practice of making telephone calls over the internet has had a number of different names, including packet voice, voice over packet, voice over the internet, internet telephone, and Voice over Ip（Voip）. But it appears the industry has settled on the term”Voice ove IP” in reference to the internet protocol, which controls the transfer of data over the internet. There are currently three ways to deliver VoIp to users, the first technique is found at the corporate level. Many companies are offering VoIP systerms that operate over a local area network. These systems involve a fair amount of equipment, such as VoIP servers, special IP-enabled telephones, and routers that can direct telephone calls. Today a large portion of corporate sites have converted their older internal telephone systems to VoIP systems that opreate over a LAN, thus converging two systems into one. A second common solution is the one often encountered at home. Using existing telephones, a special converter is added between the telephone and a high speed internet（DSL or cable modem）connection. The converter digitizes the voice signal and creates a stream of packets that are then sent over an ip connection.The third technique involves smart cell phones. Never cell technologies are all packet-based, thus requiring a telephone call to be converted to digital packets and sending those packets over IP networks.】
From the paragraph above，a popular service that has attracetd the interest of companies and home users,is termed as （） . The data transfer over the Internet is controlled by the （） . At corporate level, many companies have replaced their older internal telephone systerms with （） that oprerate over a local area network.
A、voice over the internet B、voice over packet C、Voice over IP D、internet telephony A、packet B、internet protocol C、industry D、VoIp servers A、VoIP systems B、IP-enablde telephones C、VoIP servers D、routers
第2题：
Which two statements are true about voice packets in a LAN？ （Choose two.） （）
第3题：
A. prioritization
B. classification
C. fragmentation
D. traffic shaping
第4题：
An internet is a combination of networks connected by (1). When a datagram goes from a source to a (2), it will probably pass many (3) until it reaches the router attached to the destination network. A router receives a (4) from a network and passes it to another network. A router is usually attached to several networks. When it receives a packet, to which network should it pass the packet? The decision is based on optimization: Which of the available (5) is the optimum pathway? 空白（5）处应选择（）
第5题：
To ensure voice packets are kept within the Committed Information Rate （CIR） of a Frame Relaylink， what should be used in the CPE？（）
第6题：
For acceptable voice calls， the packet error rate should be no higher than what value？（）
第7题：
Refer to the exhibit. A router has a 256 kbps Frame Relay circuit connected to interface serial 0/0. As a large FTP packet is being placed into the hardware transmit queue of interface serial 0/0， a voice packet is placed into the priority queue of that interface. How， and in what order， wi the packets be transmitted？（）
第8题：
A.0.01
B.0.1
C.1
D.2.5
第9题：
For acceptable voice calls, the packet error rate should be less than（）%
第10题：
What is the advantage of using DTX for an MS? （）