ccna 200-301 official cert guide library 1st edition pdf

ccna 200-301 official cert guide library 1st edition pdf.Extended star hierarchy typek 10Model Chapter 2 Network Interconnection and Reference Models*** I02forms are the broadcast topology and the token topology.(1) Broadcast topology. Each host sets the destination address of the data to be sent to the address of a particular network interface card on the network medium, a multicast address, or a broadcast address, and then sends that data to the transmission medium. Each host does not have to follow a certain order when using the transmission medium, i.e., first-come, first-served. Ethernet, which is most often used today, works in this way, and there is a special section on Ethernet technology later in this book.(2) Token topology. A token topology controls access to the network medium by sequentially passing an electronic token to each host. When a host receives a token, it can send data to the network medium; if that host has no data to send, then the token is passed to the next host, and so on. The main uses of token passing are token ring and fiber distributed data interface (FDDI), both of which use token passing on a physical ring topology.2.1.3 Classification by transmission medium***According to the classification of the transmission medium of the network, computer networks can be divided into two kinds of wired networks and wireless networks. Wired networks include computer networks that are connected using wired media such as coaxial cable, twisted pair, and optical fiber. Local area networks usually use a single transmission medium, while metropolitan area networks and wide area networks use multiple transmission media.Twisted-pair cable is the most common way to connect to a network because it is cheap and easy to install. (1) Types of twisted-pair cable. Twisted pair cable in computer LAN can be divided into unshielded twisted pair cable, aluminum foil shielded twisted pair cable and shielded twisted pair cable. Unshielded Twisted Pair (UTP), as shown in Figure 2-1-5, is the most common transmission medium because of its low price and easy installation and reconfiguration.It consists of two strands of very fine gauge copper wire (usually solid), insulated from each other and twisted together at fixed intervals, with the twist serving to counteract the electromagnetic fields formed during the transmission of electrical impulses. Nowadays, UTP is widely used in the field of local area networks in order to connect terminals to hubs, switches and routers. Within the transmission distance (theoretically 100m), Category 5 UTP can achieve data rates of 100Mb/s (bits per second) and even 1000Mb/s.