Sybex CCNA 640-802Chapter 2: Ethernet Networking and DataEncapsulationInstructor & Todd Lammle

Chapter 2 ObjectivesThe CCNA Topics Covered in this chapter include:Use the OSI and TCP/IP models and their associated protocols to explain how data flows in a networkSelect the appropriate media, cables, ports, and connectors to connect switches to other network devices and hostsExplain the technology and media access control method for Ethernet networks Explain network segmentation and basic traffic management conceptsSelect the appropriate media, cables, ports, and connectors to connect routers to other network devices and hosts*

Ethernet NetworkingEthernet is a contention media access method that allows all hosts on a network to share the same bandwidth of a link. Ethernet is popular because its readily scalable, meaning that its comparatively easy to integrate new technologies, such as Fast Ethernet and Gigabit Ethernet, into an existing network infrastructure. Its also relatively simple to implement in the first place, and with it, troubleshooting is reasonably straightforward.*

Ethernet Collision Detection*CSMA/CD

Half and Full Duplex*Half-duplex Ethernet is defined in the original 802.3 Ethernet; Cisco says it uses only one wire pair with a digital signal running in both directions on the wire.But full-duplex Ethernet uses two pairs of wires instead of one wire pair like half duplex. And full duplex uses a point-to-point connection between the transmitter of the transmitting device and the receiver of the receiving device.Full-duplex Ethernet can be used in three situations: With a connection from a switch to a host With a connection from a switch to a switch With a connection from a host to a host using a crossover cable

Ethernet Addressing*The MAC, or hardware, address is a 48-bit (6-byte) address written in a hexadecimal format.

Binary Addressing*Binary to Decimal Memorization Chart10000000 12811000000 19211100000 22411110000 24011111000 24811111100 25211111110 25411111111 255Conversion Example

BINARY1286432168421DECIMAL 1000010010000100132110100101101001021010111000101110001841010011010100110166

Ethernet at the Physical Layer*The IEEE 802.3 and original Ethernet Physical layer specifications.

Ethernet Cabling*Ethernet cabling is an important discussion, especially if you are planning on taking the Cisco exams.

Three types of Ethernet cables are available:

Straight-through cable Crossover cable Rolled cable

We will look at each in the following sections.

Straight Through*The straight-through cable is used to connect Host to switch or hub Router to switch or hub

Crossover Cable*The crossover cable can be used to connect Switch to switch Hub to hub Host to host Hub to switch Router direct to host

Rolled Cable*Although rolled cable isnt used to connect any Ethernet connections together, you can use a rolled Ethernet cable to connect a host to a router console serial communication (com) port.

Using Hyper Terminal*Notice the settings for Hyper Terminal

What type of cable is used?*

What type of cable is used for each connection?*

Data EncapsulationWhen a host transmits data across a network to another device, the data goes through encapsulation:It is wrapped with protocol information at each layer of the OSI model. Each layer communicates only with its peer layer on the receiving device.*

Data Encapsulation*

PDU*

Port Numbers*The Transport layer uses port numbers to define both the virtualcircuit and the upper-layer process.

Ciscos Three-Layer Model*The following are the three layers and their typical functions: The core layer: backbone The distribution layer: routing The access layer: switching

Written Labs and Review QuestionsOpen your books and go through all the written labs and the review questions.Review the answers in class.*