ccna practice questions reddit

ccna practice questions reddit.Circuit-switched services provide temporary connections over telephone lines. When networking, this service is often used to provide a backup connection to the main circuit or to temporarily increase bandwidth. More commonly today, cellular wireless services (3G and 4G) are used to support on-demand dial-up applications or to provide a backup connection.A dedicated circuit is a permanent connection between two sites with bandwidth dedicated to the company leasing the circuit. Such circuits are typically leased when they are needed to support a variety of services (e.g., voice, video, and data), have high latency requirements, and need guaranteed bandwidth.Cellular switching services have the characteristics of a private circuit. Compared to a private circuit, the advantages of a meta-switched service are that it can be connected to multiple devices through a single interface, but the disadvantages are that the service is not available everywhere, it is difficult to install and troubleshoot, and the equipment is expensive. Packet-switched services are similar to element-switched services. The use of fixed-length packets (tokens) for meta-switched services and variable-length packets for packet-switched services makes packet-switched services more suitable for providing data services, although it also provides some of the QoS features offered by meta-switched services.The two newer WAN services are DSL and cable TV cable, which are very widely used in the U.S. DSL can offer speeds of up to several Mbit/s at a much lower cost than the typical WAN circuits offered by carriers. It supports voice and video and does not require a dial-up connection (always-on.) The main disadvantage of DSL is that the transmission distance cannot exceed 18,000 feet, so it is not available everywhere. Cable access uses coaxial cable and fiber optic connections - the same media used to provide television broadcast services. It supports higher data rates than DSL and provides 24/7 connectivity as DSL does. However, cable TV cable access has two major drawbacks: it is a shared service; and it uses a logical bus topology like Ethernet, which will be discussed in Chapter 2. As a result, the more subscribers in a cell using cable cable for connectivity, the less bandwidth is available to each subscriber; also, because the medium is shared by many subscribers, there is a higher security risk, such as traffic being eavesdropped on by others.Network equipment used for WAN connectivity includes cable cable modems and DSL modems, carrier switches, CSUs/DSUs, firewalls, analog modems, NT1s, and routers.Chapter 1 Networking 7Certification H Standard 1.021.2 Network topologyVarious topologies can be used when connecting network components using cables. The topology determines how the components are connected, and Figure 1.1 shows the various mediatypes of topologies used. In a point-to-point topology, there is only one connection between two components. In this topology, two components can communicate directly, without interference from other components. This is not usually used when many components need to be connected