CCNA ICND1 100-105

What port number is used for DHCP? A. 69 B. 68 C. 67 D. 53

67 and 68 are used for DHCP

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

Frame Check Sequence

A field in many data link trailers used as part of the error detection process.

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

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

What best describes an ESS? A. A system that boosts the power output of a wireless access point so that a greater area can be covered B. An access point extends the use of a WLAN so that a connection to the world wide web can be made. C. A group of access points create one WLAN covering a larger area than one access point could cover. D. An Extensible Security System that uses the MD5 algorithm.

C. A group of access points create one WLAN covering a larger area than one access point could cover.

Which layer of the OSI model is associated with segments? A.Network layer B. Internet layer C.Physical layer D.Data Link layer

D.Data Link layer

HDLC

High-Level Data Link Control. A bit-oriented synchronous data link layer protocol developed by the International Organization for Standardization (ISO).

Network (Layer 3) Protocols and Devices

IP. Router.

TCP/IP defines two versions of IP...

IPv4 and IPv6

Physical (Layer 1) Protocols and Devices

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

Transport (Layer 4) Protocols and Devices

TCP and UDP. Hosts, firewalls

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.

Presentation Layer

This layer negotiates data formats, such as ASCII text, or image types like JPEG

Data Link Layer is in charge of...

encapsulation and addressing

OSI Layer 4 - Transport

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

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.

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.

Physical layer

This layer defines the physical characteristics of the transmission medium, including connectors, pins, use of pins, electrical currents, encoding, light modulation, and so on.

Steps using Ethernet to forward an IP packet

1. Encapsulate the IP packet between an ethernet header and ethernet trailer, creating an ethernet frame. 2. physically transmit the bits of this ethernet frame over cabling.

dotted-decimal notation (DDN)

1.1.1.1 or 3.3.3.3 are examples

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

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

Application Layer

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

IP provides several features, most importantly...

addressing and routing

line console 0 command

configures console port. eg. password

line vty

configures telnet port. eg password

Transport Layer includes ______ recovery

error

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

PDU (Protocol Data Unit)

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

IP header includes

the source and destination IP address

Segment for the ______ layer

transport

packet

A logical grouping of bytes that includes the network layer header and encapsulated data, but specifically does not include any headers and trailers below the network layer.

TCP/IP

*blank* is the most pervasively used networking model in the history of networking.

What port number is used for TFTP? A. 161 B. 143 C. 69 D. 53

C. 69

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.

Physical Layer is in charge of...

bit transmission

Ethernet

A series of LAN standards defined by the IEEE, originally invented by Xerox Corporation and developed jointly by Xerox, Intel, and Digital Equipment Corporation.

frame

A term referring to a data link header and trailer, plus the data encapsulated between the header and trailer.

Ethernet Frame

A term referring to an Ethernet data link header and trailer, plus the data encapsulated between the header and trailer.

serial interface

A type of interface on a router, used to connect to some types of WAN links, particularly leased lines and Frame Relay access links

What is a Denial of Service (DoS) attack? A. A attack whose main purpose is to break things or prevent them from working. B. An attempt to compromise a PC using DoS commands. C. An attack that prevents users from changing the settings on a PC. D. An attack that makes a server return a No Access message to a client.

A. A attack whose main purpose is to break things or prevent them from working.

What is an HTTP GET request? A. A message sent from a web client to a web server requesting that a file be sent to the client. B. A message sent from a web client to a web server asking for a list of all available files. C. A Hyper Text Transfer Protocol General Echo Time request. D. A message sent to a Cisco device at the start of in-band administration.

A. A message sent from a web client to a web server requesting that a file be sent to the client.

What does Network Access Control attempt to do? A. Ensure that all network users have a valid username and password. B. Ensure that packets not intended for a network are sent to the default gateway. C. Prevent rouge employees from stealing data. D. Detect viruses before they are installed and become active.

A. Ensure that all network users have a valid username and password.

A host receives a packet. How does it know which application the packet is destined for? A. It bases this decision on the port number assigned to the packet. B. It refers to the Application Identification Code (AIC) within the payload data. C. Packets intended for different applications are radically different so it is not difficult to know which application to send them to. D. It sends the packet to all possible applications in random order until one application accepts the packet.

A. It bases this decision on the port number assigned to the packet.

Which layer(s) of the TCP/IP model equates most directly to the Data Link and Physical layers of the OSI model? A. Network Access Layer. B. The MAC and LLC layers. C. Transport Layer. D. IPX Layer

A. Network Access Layer.

Which layer of the OSI model is associated with authentication services? A. The Application layer. B. The Security layer. C. The Session layer. D. The Presentation layer.

A. The Application layer.

Extended Service Set (ESS)

An extended service set (ESS) is one or more interconnected basic service sets (BSSs) and their associated LANs. Each BSS consists of a single access point (AP) together with all wireless client devices (stations, also called STAs) creating a local or enterprise 802.11 wireless LAN (WLAN). To the logical link control layer (part of layer 2 of the 7-layer OSI Reference Model) the ESS appears as a solitary BSS at any one of the STAs.

What are the advantages of using a layered network model (choose 2)? A. The model ensures that all vendors do not implement new ideas which might impact on the efficient functioning of the internet. B. Standard interfaces between the layers allow hardware manufacturers and software developers to create products that interact properly with products from other vendors. C. People involved in developing the model get to go to conferences in far off locations. D. Complex systems are broken into smaller parts and are therefore easier to understand.

B and D. Complex systems are broken into smaller parts and are therefore easier to understand. Standard interfaces between the layers allow hardware manufacturers and software developers to create products that interact properly with products from other vendors.

An attack which attempts to learn an IP address would be know as? A. A Get Request Attack B. A Reconnaissance Attack. C. A DNS Attack D. An Routing Targeted Attack.

B. A Reconnaissance Attack

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 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

What term is used to describe a communication between one layer of a networking model and the layer immediate above or below? A. OSI interaction. B. Client/server interaction. C. Adjacent layer interaction. D. Layer 1 interaction.

C. Adjacent layer interaction.

A host has just sent a packet using CSMA/CD logic. What does it do now? A. Wait until it receives confirmation from the destination host, then send another packet. B. Forget about the packet altogether and send some more before another host can take control of the media. C. Listen for collisions. D. Send a "packet sent" notice to the Ethernet Logging Database (EDB).

C. Listen for collisions.

Which layer of the OSI model is associated with IP? A. The Internet Layer. B. The Transport layer. C. The Network layer. D. The Data Link layer.

C. The Network layer.

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.

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.

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

Ethernet and PPP

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

segment

In TCP, a term used to describe a TCP header and its encapsulated data (also called an L4PDU). Also in TCP, the process of accepting a large chunk of data from the application layer and breaking it into smaller pieces that fit into TCP segments. In Ethernet, a segment is either a single Ethernet cable or a single collision domain (no matter how many cables are used).

Transport Layer

In function, much like TCP/IP's transport layer. This layer focuses on data delivery between the two endpoint hosts (for example, error recovery)

IEEE

Institute of Electrical and Electronics Engineers. A professional organization that develops communications and network standards, among other activities.

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.

Data link layer

Like the TCP/IP data link layer, this layer defines the protocols for delivering data over a particular single type of physical network (for example, the Ethernet data link protocols)

Network Layer

Like the TCP/IP network (Internet) layer, this layer defines logical addressing, routing (forwarding), and the routing protocols used to learn routes

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

Network Access layer (Original TCP/IP Model)

de-encapsulation

On a computer that receives data over a network, the process in which the device interprets the lower-layer headers and, when finished with each header, removes the header, revealing the next-higher-layer PDU.

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.

How to memorize the 7 OSI layers?

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

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.

Application Layer

Provides an interface from the application to the network by supplying a protocol with actions meaningful to the application, for example, "get web page object"

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.)

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.

Encapsulation

The placement of data from a higher-layer protocol behind the header (and in some cases, between a header and trailer) of the next-lower-layer protocol. For example, an IP packet could be encapsulated in an Ethernet header and trailer before being sent over an Ethernet

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.

Session Layer

This layer provides methods to group multiple bidirectional messages into a workflow for easier management and easier backout of work that happened if the entire workflow fails.

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.

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

enable secret command

sets encrypted password