Networking Exam 2

Is 10.3.45.78 routable on the internet? If yes indicate class. If no why?

No, Private A

Is 222.546.23.4 routable on the internet? If yes indicate class. If no, why?

No, 546>255

Is 187.34.24.56 routable on the internet? If yes indicate class. If no, why?

Yes, Class B

Is 195.168.3.1 routable on the internet? If yes indicate class. If no, why?

Yes, Class C

Subnetting is _

the practice of dividing a network into two or more networks

Routing Tables _

specifies how messages will travel through the network

T or F: Compared to a hub, a switch is intelligent and can read the frame and determine where to send it

True

T or F: The IP address 127.192.240.0 is a valid subnet mask

False (needs to be continuous 1’s, then 0’s)

What component of the computer provides it with a MAC address?

NIC (network card interface)

A MAC address is composed of two 24-bit numbers. What does the first 24-bit number represent?

It’s the organizationally unique identifier for the manufacturer of the device

A network address is 131.247.160.0/19. The 19 implies that _

19 bits are reserved for the network part of IP addresses on the network

The IPv6 address below 2001:0db8:0000:0000:aaaa:0000:eeee:0001 should be written as _

2001:db8::aaaa:0:eeee:1

The advantage(s) of using two different addresses on a computer (MAC address and IP address) include:

It is possible to upgrade the IP software without upgrading the network hardware

It is possible to upgrade the network hardware without upgrading the IP software

The data link and network layers can be independent of each other

Flow control in TCP is used to _

Slow down the sender if necessary

Given the subnet 10.5.12.0/22, which of the following IP addresses is a valid host address residing within the network?

A. 10.5.12.0

B. 10.5.16.1

C. 10.5.14.255

D. 10.5.15.255

10.5.14.255

A routing table is a table stored in a router which keeps track of _

the best paths to destination networks

Suppose you have leased the following network ID 145.34.0.0 and you want to divide it into 20 subnets to correspond to the 20 different departments in your company: What class of an address is this?

Class B

Suppose you have leased the following network ID 145.34.0.0 and you want to divide it into 20 subnets to correspond to the 20 different departments in your company: What is the default subnet mask for this class?

255.255.0.0 or /16

Suppose you have leased the following network ID 145.34.0.0 and you want to divide it into 20 subnets to correspond to the 20 different departments in your company: How many bits from the host space do you need to use so that you can create 20 subnets?

5

Suppose you have leased the following network ID 145.34.0.0 and you want to divide it into 20 subnets to correspond to the 20 different departments in your company: How many subnets will you be able to create with these borrowed bits?

32 (2^5=32)

Suppose you have leased the following network ID 145.34.0.0 and you want to divide it into 20 subnets to correspond to the 20 different departments in your company: What is the new subnet mask in Binary, Dotted Decimal, and Slash Notation?

11111111.11111111.11111000.00000000, 255.255.248.0, /21

Suppose you have leased the following network ID 145.34.0.0 and you want to divide it into 20 subnets to correspond to the 20 different departments in your company: If the new subnet mask is /21, how many unique hosts can you put on each of these subnets?

2046

Suppose you have leased the following network ID 145.34.0.0 and you want to divide it into 20 subnets to correspond to the 20 different departments in your company: If the new subnet mask is /21, what is the maximum number of unique hosts you can put on each of these subnets?

2046

Purpose of the data link layer is _

to move a message or a frame from one hub to another hub

What is a hub?

A device that has multiple ports that accepts ethernet connections from network devices

Routers connect

two or more networks

The network architecture component which contains the organization’s servers is called _

data center

When the data link layer detects errors in incoming data, it typically _

deletes the data

A 12-bit binary number can be used to uniquely label _ objects

4096

T or F: The building block process of network design focuses on predicting user traffic to optimize network capacity

False

T or F: Rather than predicting user traffic, the building block process emphasizes simplicity of design

True

Is 128.192.5.4 routable on the internet? If yes indicate class. If no, why?

Yes, Class B

Is 10.2.56.145 routable on the internet? If yes indicate class. If no, why?

No, Private A

Is 127.0.0.0 routable on the internet? If yes indicate class. If no, why?

No, Loopback

Given the subnet 10.5.12.0/22, which of the following IP addresses is a valid host address residing within the network?

A. 10.5.14.255

C. 10.5.12.0

D. 10.5.13.272

E. 10.5.15.255

10.5.14.255

If an error is detected in the network architecture, which layer fixes it?

TCP Transport Layer

Information Bits are those used to convey the user’s _

meaning

Overhead bits are used for purposes such as _ and marking the start and end of _

error checking/characters and packets

How long is IPV4?

32 bits (4 bytes)

How long is IPV6

128 bits (16 bytes)

T or F: IP addresses are NOT assigned at random like MAC addresses or even on first come first serve basis

True

there are two addresses on every network that are reserved – the first one is called _ and the second is called _

subnet ID/broadcast network

What is controlled access?

A type of media access control where the wireless access point controls the circuit and determines which clients can transmit at what times (By request, roll call polling, token passing)

What is contention based access?

A type of media control where computer wait until the circuit is free (no other computers are transmitting) and then transmit whenever they have data to send

Most wireless LAN’s use _

controlled access

_ is commonly used in ethernet LAN’s

contention

_ are controlled by network hardware and software, typically consist of corrupted and lost data

network error

_ are controlled by application programs and typically result from a mistake in typing a number

human erros

Sources of error include:

line outages, white noise, impulse noises, cross talk, echo, attenuation, intermodulation noise, jitter, harmonic distortion

A data link protocol determines _

who can transmit at what time, where a message begins and ends, and how a receiver recognizes and corrects a transmission error

An objective of the network:

move as many bits as possible with minimum errors (higher efficiency and lower cost)

What is a session?

a conversation between two computers, when the sender wants to send a message it first establishes a session with the destination computer

What are the responsibilities of the transport layer (TCP)?

Linking to the application layer, segmentation (splitting large data into small chunks) so it can be sent over networks, session management (end to end responsibility)

What are the responsibilities of the network layer (IP)?

Addressing (finding destination address), routing (finding best route through network)

What does a TCP 3 way handshake look like?

Client - Hi, I want to talk to you

Server - Sure, I also want to talk. Are you ready?

Client - Ok, lets talk

UDP (user datagram protocol)

Connection-less protocol, unreliable (used to send only 1 frame), does not check for lost messages so a datagram is occasionally lost and the message must be resent. Decision on which protocol to use is left to the engineer

TCP (transmission control protocol)

Connection-oriented protocol, reliable (establishes connection with 3 way handshake), 4 way to end, many applications use this

IP (internet protocol)

Routable, unreliable (does not do error checking, just goes and sends), address assignment (where IP address comes from, static vs dynamic)

ICMP (internet control message protocol)

Between routers

ARP (address resolution protocol)

Non-routable (only function locally), MAC address

How many bytes of MAC address?

6 bytes

What is the type of address for the application layer?

Web url, email (assigned by software)

What is the type of address for the transport layer?

port number (well-known, registered, and temporary) (assigned by software)

What is the type of address for the network layer?

IP address: IPV4 and IPV6 (assigned by software)

What is the type of address for the data link layer?

MAC (media access control) (assigned by hardware, typically manufacturers)

There are _ addresses in the IPV4 address space

4.3 billion

IP addresses are managed by _

IANA (internet assigned numbers authority) (assigns these numbers to regional internet registries)

What is ARP (address resolution protocol) used for?

to find a MAC address from a host where it knows its IP address, maps an IP to a MAC address

Centralized routing

one computer does all the routing, common in host-based architecture, send all the messages to the central computer which performs the task of ‘routing’

Static decentralized routing

each computer does its own routing, routing tables change only as the network changes, static routing is commonly used in networks that have few routing options that seldom change

Dynamic decentralized routing

each computer does its own routing, routing tables are adjusted on the fly based on distance vector (# of hops) and link state (determines how fast each route is)

Enterprise edge

the parts of a network that are at the edge of an enterprise campus and connect that campus to the rest of the world

Needs analysis

the process during which the designer attempts to understand the fundamental current and future network needs of the various users, departments, and applications

Technology design

examines the available technologies and assesses which options will meet users’ needs

Cost assessment

The relative costs of the technologies are considered

LAN (local area network) (access layer)

enables users to access the network (network hub, switches, and AP’s)

Building backbone network (distribution layer)

It distributes network traffic to and from the LAN’s (faster switches)

Campus backbone (core layer)

It connects all the buildings on one campus (routers or 3 layer switches)

Data center

data center contains the organization’s servers (database servers, email servers)

WAN (wide area network)

private network that connects its different campus locations, usually leased from a common carrier such as AT&T; used for private use of the organization and only carries its network traffic from one campus to another

Internet access

It enables the organization to connect to the internet. Internet access carries traffic from many different organizations

E-commerce edge

A special LAN with a group of servers that enables electronic data exchange between organization and the external entities with which it does business (customers and suppliers)

Parity check

one additional bit is added to each byte in the message, the value of this addition is based on the number of 1’s in each byte transmitted

Checksum

typically 1 byte, added to the end of the message, calculated by adding the decimal value of each character in the message, dividing the sum by 255, and using the remainder as one

Cyclic redundancy check (crc)

a message is treated as one long binary number, which is divided by a preset number, and the remainder is used as a code