Networking Basics Module 5 – 7 Checkpoint Test Online

Hint

The OSI transport layer is functionally equivalent to the TCP/IP transport layer, and the OSI network layer is equivalent to the TCP/IP Internet layer. The OSI data link and physical layers together are equivalent to the TCP/IP network access layer. The OSI session layer (with the presentation layer) is included within the TCP/IP application layer.

Hint

TCP/IP is a protocol stack that contains a lot of other protocols such as HTTP, FTP, and DNS. The TCP/IP protocol stack is required to be used when communicating on the Internet. A MAC address is an address that is burned into an Ethernet network card. OSI is the 7 layer model that is used to explain how networking works.

Hint

Place the options in the following order:

internet	determines the best path to forward data through the network.
application	represents data to the user, data encoding, and dialog control.
network access	controls hardware devices and media that make up the network.
transport	supports communication between diverse devices across networks.

Hint

A data communication protocol is a set of rules that govern the communication process.

Hint

The TCP/IP internet layer provides the same function as the OSI network layer. The transport layer of both the TCP/IP and OSI models provides the same function. The TCP/IP application layer includes the same functions as OSI Layers 5, 6, and 7.

Hint

The TCP/IP model consists of four layers: application, transport, internet, and network access. The OSI model consists of seven layers: application, presentation, session, transport, network, data link, and physical. The top three layers of the OSI model: application, presentation, and session map to the application layer of the TCP/IP model.

Hint

All communication methods include a message source, destination, and a transmission medium.

Hint

In twisted-pair cables, wires are grouped in pairs and twisted together to reduce interference. The pairs of wires are colored so that the same wire at each end can be easily identified.

Hint

Data is transmitted across a network on media. Modern networks primarily use three types of media to interconnect devices:

• Metal wires within cables (copper cable, such as twisted-pair and coaxial cable) – Data is encoded into electrical impulses.
• Glass or plastic fibers within cables (fiber-optic cable) – Data is encoded into pulses of light.
• Wireless transmission – Data is encoded via modulation of specific frequencies of electromagnetic waves.

Hint

Copper cabling is usually cheaper and easier to install than fiber optic cabling. However, fiber cables generally have a much greater signaling range than copper.

Hint

Fiber-optic cables can carry very large amounts of data and are used extensively by telephone companies and in backbone networks.

Hint

Coaxial cable is the kind of copper cable used by cable TV companies. It is used to connect TV sets to the wall jacks that are connected to a cable TV company. It is also used for connecting the various components which make up satellite communication systems.

Hint

Criteria for choosing a network medium are the distance across which the selected medium can successfully carry a signal, the environment in which the selected medium is to be installed, the amount of data and the speed at which the data must be transmitted, and the cost of the medium and its installation.

Hint

Network cabling includes different types of cables:

• Twisted-pair Ethernet cables consist of four pairs of color-coded wires that have been twisted together and then encased in a flexible plastic sheath.
• Coaxial cables use a copper conductor and a layer of flexible plastic insulation that surrounds the copper conductor.
• Fiber-optic cables are flexible, extremely thin, transparent strands of glass surrounded by plastic insulation.

Hint

When a switch receives a frame with a source MAC address that is not in the MAC address table, the switch will add that MAC address to the table and map that address to a specific port. Switches do not use IP addressing in the MAC address table.

Hint

Encapsulation is the process of placing one type of message format into another. On computer networks this process is known as encapsulation. Once a message is encapsulated, it is called a frame.

Hint

Every frame that enters a switch is checked for new information to learn. It does this by examining the source MAC address of the frame and port number where the frame entered the switch: If the source MAC address does not exist in the MAC address table, the MAC address and incoming port number are added to the table.

Hint

When a switch powers on, the MAC address table is empty. The switch builds the MAC address table by examining the source MAC address of incoming frames. The switch forwards based on the destination MAC address found in the frame header. If a switch has no entries in the MAC address table or if the destination MAC address is not in the switch table, the switch will forward the frame out all ports except the port that brought the frame into the switch.

Hint

Important actions that a switch performs are as follows: – When a frame comes in, the switch examines the Layer 2 source address to build and maintain the Layer 2 MAC address table. – It examines the Layer 2 destination address to determine how to forward the frame. When the destination address is in the MAC address table, then the frame is sent out a particular port. When the address is unknown, the frame is sent to all ports that have devices connected to that network.

Hint

To maintain the MAC address table, the switch uses the source MAC address of the incoming packets and the port that the packets enter. The destination address is used to select the outgoing port.

Hint

According to the Ethernet standards, each Ethernet frame can carry 46 to 1500 bytes of user data. During the encapsulation process, other fields are added, such as destination MAC address, source MAC address, and FCS. The size of Ethernet frames is normally limited to a maximum of 1518 bytes and a minimum of 64 bytes.