CCNA1-第七章.doc

1 第七章法 窗体顶端 What is a function of the data link layer? provides the formatting of data provides end-to-end delivery of data between hosts provides delivery of data between two applications provides for the exchange data over a common local media 窗体底端 2 窗体顶端 What is the purpose of the preamble in an Ethernet frame? is used as a padding for data is used for timing synchronization is used to identify the source address is used to identify the destination address 窗体底端 3 窗体顶端 What are three characteristics of valid Ethernet Layer 2 addresses? (Choose three.) They are 48 binary bits in length. They are considered physical addresses. They are generally represented in hexadecimal format. They consist of four eight-bit octets of binary numbers. They are used to determine the data path through the network. They must be changed when an Ethernet device is added or moved within the network. 窗体底端 4 窗体顶端 Refer to the exhibit. How many CRC calculations will take place as traffic routes from the PC to the laptop? 1 2 4 6 8 16 窗体底端 5 窗体顶端 What is a primary purpose of encapsulating packets into frames? provide routes across the internetwork format the data for presentation to the user facilitate the entry and exit of data on media identify the services to which transported data is associated 窗体底端 6 窗体顶端 What determines the method of media access control? (Choose two.) network layer addressing media sharing application processes logical topology intermediary device function 窗体底端 7 窗体顶端 Which sublayer of the data link layer prepares a signal to be transmitted at the physical layer? LLC MAC HDLC NIC 窗体底端 8 窗体顶端 What is true regarding media access control? (Choose three.) Ethernet utilizes CSMA/CD defined as placement of data frames on the media contention-based access is also known as deterministic 802.11 utilizes CSMA/CD Data Link layer protocols define the rules for access to different media controlled access contains data collisions 窗体底端 9 窗体顶