CCENT/CCNA ICND1 640-822

Collision domain

The set of devices whose frames could collide.

Same-layer interaction on different computers

The two computers use a protocol to communicate with the same layer on another computer. The protocol defined by each layer uses a header that is transmitted between the computers to communicate what each computer wants to do.

dotted-decimal notation (DDN)

1.1.1.1 or 3.3.3.3 are examples

HTTP, POP3 and SMTP is located on what TCP/IP layer?

Application Layer

Network (Layer 3) Protocols and Devices

IP. Router.

TCP/IP Network Access Layer

The TCP/IP model's network access layer defines the protocols and hardware required to deliver data across some physical network.

Data Link Layer is in charge of...

encapsulation and addressing

Transport Layer includes ______ recovery

error

OSI Layer 4 - Transport

focuses on issues related to data delivery to another computer (for instance, error recovery and flow control).

TCP/IP network access layer includes two distinct functions:

functions related to the physical transmission of the data, plus the protocols and rules that control the use of the physical media.

OSI network layer defines

logical addressing and routing, as does the TCP/IP Internet layer.

Frame for the ______ layer

network access

Encapsulation

refers to the process of putting headers (and sometimes trailers) around some data.

PDU (Protocol Data Unit)

represents the bits that include the headers and trailers for that layer, as well as the encapsulated data.

Physical Layer is in charge of...

bit transmission

TCP/IP host sends data can be viewed as a five-step process. Step 4

Encapsulate the data supplied by the Internet layer inside a data link layer header and trailer. This is the only layer that uses both a header and a trailer.

TCP/IP host sends data can be viewed as a five-step process. Step 2

Encapsulate the data supplied by the application layer inside a transport layer header. For end-user applications, a TCP or UDP header is typically used.

How to memorize the 7 OSI layers?

Please Do Not Take Sausage Pizzas Away (Layers 1 to 7)

OSI Layer 6 - Presentation

This layer's main purpose is to define and negotiate data formats, such as ASCII text, EBCDIC text, binary, BCD, and JPEG. Encryption is also defined by OSI as a presentation layer service.

TCP/IP host sends data can be viewed as a five-step process. Step 5

Transmit the bits. The physical layer encodes a signal onto the medium to transmit the frame.

TCP and UDP are located on what TCP/IP layer?

Transport Layer

The process of a web server adding a TCP header to the contents of a web page, followed by adding an IP header, and then adding a data link header and trailer is an example of what? a. Data encapsulation b. Same-layer interaction c. OSI model d. All of these answers are correct.

A

Which OSI layer defines the standards for cabling and connectors? a. Layer 1 b. Layer 2 c. Layer 3 d. Layer 4 e. Layer 5 f. Layer 6 g. Layer 7

A

Which of the following protocols are examples of TCP/IP network access layer protocols? (Choose two answers.) a. Ethernet b. HTTP c. IP d. UDP e. SMTP f. TCP g. PPP

A, G

The process of HTTP asking TCP to send some data and making sure that it is received correctly is an example of what? a. Same-layer interaction b. Adjacent-layer interaction c. OSI model d. All of these answers are correct.

B. Adjacent-layer interaction occurs on one computer, with two adjacent layers in the model. The higher layer requests services from the next lower layer, and the lower layer provides the services to the next higher layer.

The process of TCP on one computer marking a TCP segment as segment 1, and the receiving computer then acknowledging the receipt of TCP segment 1 is an example of what? a. Data encapsulation b. Same-layer interaction c. Adjacent-layer interaction d. OSI model e. All of these answers are correct.

B. Same-layer interaction occurs on multiple computers. The functions defined by that layer typically need to be accomplished by multiple computers—for example, the sender setting a sequence number for a segment, and the receiver acknowledging receipt of that segment. A single layer defines that process, but the implementation of that layer on multiple devices is required to accomplish the function.

Which OSI layer defines the functions of logical network-wide addressing and routing? a. Layer 1 b. Layer 2 c. Layer 3 d. Layer 4 e. Layer 5 f. Layer 6 g. Layer 7

C

Which of the following terms are not valid terms for the names of the seven OSI layers? (Choose two answers.) a. Application b. Data link c. Transmission d. Presentation e. Internet f. Session

C, E

OSI Layer 1 - Physical

This layer typically refers to standards from other organizations. These standards deal with the physical characteristics of the transmission medium, including connectors, pins, use of pins, electrical currents, encoding, light modulation, and the rules for how to activate and deactivate the use of the physical medium.

OSI Layer 3 - Network

The network layer defines three main features: logical addressing, routing (forwarding), and path determination. Routing defines how devices (typically routers) forward packets to their final destination. Logical addressing defines how each device can have an address that can be used by the routing process. Path determination refers to the work done by routing protocols to learn all possible routes, and choose the best route.

TCP/IP host sends data can be viewed as a five-step process. Step 1

Create and encapsulate the application data with any required application layer headers. For example, the HTTP OK message can be returned in an HTTP header, followed by part of the contents of a web page.

Which of the following terms is used specifically to identify the entity created when encapsulating data inside data link layer headers and trailers? a. Data b. Chunk c. Segment d. Frame e. Packet f. None of these—there is no encapsulation by the data link layer.

D

Which of the following protocols are examples of TCP/IP transport layer protocols? (Choose two answers.) a. Ethernet b. HTTP c. IP d. UDP e. SMTP f. TCP

D, F

OSI Layer 5 - Session

The session layer defines how to start, control, and end conversations (called sessions). This includes the control and management of multiple bidirectional messages so that the application can be notified if only some of a series of messages are completed. This allows the presentation layer to have a seamless view of an incoming stream of data.

TCP/IP host sends data can be viewed as a five-step process. Step 3

Encapsulate the data supplied by the transport layer inside an Internet layer (IP) header. IP defines the IP addresses that uniquely identify each computer.

Data link (Layer 2) Protocols and Devices

Ethernet (IEEE 802.3), HDLC, Frame Relay, PPP. LAN switch, wireless access point, cable modem, DSL modem

Which OSI layer defines the standards for data formats and encryption? a. Layer 1 b. Layer 2 c. Layer 3 d. Layer 4 e. Layer 5 f. Layer 6 g. Layer 7

F

Packet for the ______ layer

Internet

IP is located on what TCP/IP layer?

Internet Layer

OSI Layer 7 - Application

Layer 7 provides an interface between the communications software and any applications that need to communicate outside the computer on which the application resides. It also defines processes for user authentication.

Ethernet, PPP, Frame Relay and T1 is located on what Original TCP/IP layer?

Network Access layer (Original TCP/IP Model)

Adjacent-layer interaction on the same computer

On a single computer, one layer provides a service to a higher layer. The software or hardware that implements the higher layer requests that the next lower layer perform the needed function.

Note

Protocols define both headers and trailers for the same general reason, but headers exist at the beginning of the message, and trailers exist at the end.

Physical (Layer 1) Protocols and Devices

RJ-45, EIA/TIA-232, V.35, Ethernet (IEEE 802.3). LAN hub, LAN repeater, cables

The TCP/IP model both defines and references a large collection of protocols that allow computers to communicate. To define a protocol, TCP/IP uses documents called

Requests for Comments (RFC). (You can find these RFCs using any online search engine.)

Transport (Layer 4) Protocols and Devices

TCP and UDP. Hosts, firewalls

Application, presentation, session (Layers 5-7) - Protocols and Devices

Telnet, HTTP, FTP, SMTP, POP3, VoIP, SNMP. Firewall, intrusion detection systems, hosts

OSI Layer 2 - Data Link

The data link layer defines the rules that determine when a device can send data over a particular medium. Data link protocols also define the format of a header and trailer that allows devices attached to the medium to successfully send and receive data.

IP provides several features, most importantly...

addressing and routing

IP header includes

the source and destination IP address

Segment for the ______ layer

transport