cisco ccna or network+

cisco ccna or network+.The 802.11 standard is just one branch of the IEEE 802 standard that covers wireless LANs.The Ethernet standards collection encapsulates several standards that define the functionality of the physical and data link layers. The Ethernet physical layer involves several standards, depending on the physical medium used to carry the information. The Ethernet Medium Access Control (MAC) sublayer, described in the IEEE 802.3 standard, and the Logical Link Control (LLC) sublayer, described in the IEEE 802.2 standard, together provide the data link layer functionality.Note that people sometimes refer to MAC as MediaAccessControl rather than MediaAccess Control (Medium Access Control). According to the I EEE 802 standard, both designations are correct. In theFor the rest of this book, the term Medium Access Control or simply MACO will be used.The original purpose of the LLC function was to allow multiple types of Layer 3 protocols to operate in concert with the MAC. However, within the context of today'smost networks in use today will only run one type of Layer 3 protocol, the Internet Protocol (IP), and the LLC function will be difficult toThe LLC function is difficult to use because the MAC function can encapsulate IP (packets) directly.The next section provides an overview of the Ethernet physical layer and MAC layer standards. The physical layer covers a number of standards that cover the various physical (networking) methods that may be used when deploying a LAN. For example, within a LAN, data can be transmitted over media such as fiber, copper, etc. Two such Ethernet standards are 10BASE-T and 1000BASE.LX. Each Ethernet standard defines a maximum transmission rate and a maximum transmission distance between two directly connected sites. Ethernet transmission rates have evolved tremendously (and continue to evolve). Several common Ethernet physical layer standards are shown in Table 1-5.Table 1-5 Several Commonly Used Ethernet Physical Layer Standards