Network and Security – Foundations Test Questions with 100% Complete Answers, Rated A+

Physical Layer (Layer 1) - This layer is responsible for the physical connections of the devices in the network. This layer is implemented through the use of devices such as hubs, repeaters, modem devices, and physical cabling. Data Link Layer (Layer 2) - This layer is responsible for the error-free delivery of data to the receiving device or node. This layer is implemented through the use of devices such as switches and bridge devices, as well as anything with a network interface, like wireless or wired network cards. Network Layer (Layer 3) - This layer is responsible for the transmission of data between hosts in different networks as well as routing of data packets. This layer is implemented through the use of devices such as routers and some switches. Transport Layer (Layer 4) - This layer provides services to the application layer and receives services from the network layer. It is responsible for the reliable delivery of data. It segments and reassembles data in the correct order for it to be sent to the receiving device. This layer is often called the heart of OSI. Session Layer (Layer 5) - This layer is responsible for connection establishment, session maintenance, and authentication. Presentation Layer (Layer 6) - This layer is responsible for translating data from the application layer into the format required to transmit the data over the network as well as encrypting the data for security if encryption is used. Application Layer (Layer 7) - This layer is responsible for network applications (like HTTP or FTP) and their production of data to be transferred over the network. Modem - A device that allows computers to communicate over telephone lines Router - A device that transfers data from one network to another in an intelligent way Switch - A device for making, breaking, or changing the connections in an electrical circuit. Bridge - A device that connects two or more networks. Forwards the data to the next network without analysis. Repeater - A device that picks up signals from lower-power radio units, such as mobile and portable radios, and retransmits them at a higher power. It allows low-power radio signals to be transmitted over longer distances. Hub - A device that uses its ports to connect devices (computers, printers, etc.) together What Layer(s) does a Switch operate at - Operates at the Network and Data Link Level What Layer(s) does a Router operate at - Operates at the Network Level What Layer(s) does a Modem operate at - Operates at the Data Link and Physical Level What Layer(s) does a Bridge operate at - Operates at the Data Link Level What Layer(s) does a Hub operate at - Operates at the Physical Level What Layer(s) does a Repeater operate at - Operates at the Physical Level