Chapter 2 Essentials Flashcards
Describe the operation of Carrier Sense Multiple Access with Collision Detection (CSMA/CD).
CSMA/CD is a protocol. Although it does not eliminate collisions, it helps to greatly reduce them, which reduces retransmissions, resulting in a more efficient transmission of data for all devices. Detects a collision in the medium and backing off (after transmitting a jam signal) as necessary. Assume, we have a LAN with a number of hosts. When one host wants to transmit a frame, it listens on the medium to check if the medium is busy.
Differentiate half-duplex and full-duplex communication and define the requirements to utilize each method.
Full-duplex Ethernet uses two pairs of wires at the same time instead of one wire pair like half-duplex. Full-duplex allows for sending and receiving at the same time, using different wires to eliminate collisions, while half-duplex can send or receive but not at the same time and still can suffer collisions. To use full-duplex, the devices at both ends of the cable must be capable of and configured to perform full-duplex.
Describe the sections of a MAC address and the information contained in each section.
The MAC, or hardware, address is a 48-bit (6-byte) address written in a hexadecimal format. The first 24 bits, or 3 bytes, are called the organizationally unique identifier (OUI), which is assigned by the IEEE to the manufacturer of the NIC. Second half is the vendor assigned
Identify the fields in the Data Link portion of an Ethernet frame.
The fields in the Data Link portion of a frame include the preamble, Start Frame Delimiter, destination MAC address, source MAC address, Length or Type, Data, and Frame Check Sequence.
Identify the IEEE physical standards for Ethernet cabling
These standards describe the capabilities and physical characteristics of various cable types and include but are not limited to 10Base-2, 10Base-5, and 10Base-T.
Differentiate types of Ethernet cabling and identify their proper application.
The three types of cables that can be created from an Ethernet cable are straight-through (to connect a PC’s or router’s Ethernet interface to a hub or switch), crossover (to connect hub to hub, hub to switch, switch to switch, or PC to PC), and rolled (for a console connection from a PC to a router or switch).
Describe the data encapsulation process and the role it plays in packet creation
Data encapsulation is a process whereby information is added to the frame from each layer of the OSI model. This is also called packet creation. Each layer communicates only with its peer layer on the receiving device.
Understand how to connect a console cable from a PC to a router and switch.
Take a rolled cable and connect it from the COM port of the host to the console port of a router. Start your emulations program such as
putty or SecureCRT and set the bits per second to 9600 and flow control to None.
Identify the layers in the Cisco three-layer model and describe the ideal function of each layer
The three layers in the Cisco hierarchical model are the core (responsible for transporting large amounts of traffic both reliably and quickly), distribution (provides routing, filtering, and WAN access), and access (ensures that packets are delivered to end user devices).
