Global Networking Final

A lesson of XSS is that programmers should never trust ________.

user input

Phase Modulation uses two _____ levels.

wave

________ is a general naming system for the Internet.

DNS

Which of the following provides end-to-end encryption?

S/MIME

The Internet is a ________.

WAN

NAT ________.

both allows a firm to have more internal IP addresses and provides some security

The Internet is organized in a ________.

mesh

".com" is a ________.

top-level domain

If someone says that a 1-bit flag is not set, this means its value is ________.

0

In a routing table, Rows 47 and 3497 both match the destination IP address of an arriving packet's IP address. What row will the router look at first when trying to find matching rows?

1

Which of the following already runs to nearly all customer premises?

1-pair VG UTP

1. What is the speed of a T1 line? 2. How many voice channels can a T3 line carry?

1. 1.544 Mbps 2. 672

1. If 4 different amplitudes are used, how many bits can be transmitted with each amplitude change? 2. If 8 different frequencies are used, how many bits can be transmitted with each frequency change? Hint: Amplitudes and Frequencies represent "states" as we have discussed earlier in the semester

1. 4 amplitudes -> 00,01,10,11 -> 2 bits 2. 8 frequencies -> 000,001,010,011 ,100,101,110, 111 -> 3 bits

1. What type of orbit does a satellite have to be in to appear stationary to an earth receiving station? 2. What altitude does the satellite have to orbit to achieve this?

1. Geosynchronous 2. 22,300 miles

Assume that an average SNMP response message is 100 bytes long. Assume that a manager sends 4,000 SNMP Get commands each second. a) What percentage of a 10 Mbps WAN link would the response messages represent? Hint: A byte is 8 bits.

100x8 = 800 bits 800x4000 = 3200000 bps 3200000/100000000 = 3.2% 4000 messages * 100 bytes * 8 bits/byte -> 3,200,000 bits/second / 10,000,000 bps -> .32 -> 32%

If I simplify the IPv4address 2001:0000:0000:00fe:3270:0000:0000:cdef., I get ________.

2001:0:0:00fe:3270::cdef

You have a 20-bit network part and a 4-bit subnet part. How many hosts can you have per subnet?

254

A mask has ________ bits.

32

The chapter speaks about QAM (Quadrature Amplitude Modulation), but this is just an implementation of what we've seen before. If there are 16 states (or signal combinations) and a baud rate (number of signals/second) of 8000/second, how many bps could I send? Hint: You first have to figure out how many bits I can send with 16 states, then multiply by the number of signals/second.

32,000 bps

The main version of Internet Protocol in use today is IP version

4

Typical T1 voice lines have 24 channels with each capable of carrying 1 telephone conversation with "8-bit" quantization and 8,000 samples/second. If we apply this to storiing a voice clip on disk, how much storage (in bits) does a 10 second clip take.

640,000 bits

In IP subnet planning, you need to have at least 130 subnets. How large should your subnet part be?

8

QAM (Quadrature Amplitude Modulation) uses phase and amplitude to indicate different signals so that multiple bits can be sent in a clock cycle. More generally, there is a relationship between the number of bits per second (bps) and the number of different signal combinations (states) and the baud rate (signal changes per second). If I want a data rate of 30,000 bps and the baud rate is 10,000 how many states do I need.

8

Typical T1 voice lines have 24 channels with each capable of carrying 1 telephone conversation with "8-bit" quantization and 8,000 samples/second. Suppose the quantization is 12-bits (same sampling rate). How many bits to store a 10 second video clip.

960,000

________ is/are widely used in Europe for PSTN signaling.

C7

To use a leased line, the customer must have a(n) ________ at each site.

CSU/DSU

There is a row for each host address in a(n) ________.

Ethernet switching table

In e-mail, UNICODE enhances security.

False

Which of the following is a file format standard?

HTML

________ is the process of presenting external IP addresses that are different from internal IP addresses used within the firm.

NAT

In the mask /14, how many 1s are there? a) 8 b) 16 c) 24 d) None of these

None of these

A customer's leased line to its ISP connects to the ISP's ________.

POP

Codec data comes after the ________ header in VoIP transport frames.

RTP

PSTN signaling in the United States uses ________.

SS7

Which type of service manages application software for users?

SaaS

If you need speeds of 1.2 Mbps between two corporate sites in the United States, you would need a ________ leased line.

T1

For the transport layer, VoIP uses ________ for transport transmission.

UDP

Simpify the following IPv6 addresses: a) 2001:0000:0000:00fe:0000:0000:0000:cdef. b) 2001:0000:0000:00fe:0000:0000:ba5a:cdef.

a) 2001:0:0:fe::cdef b) 2001::fe:0:0:ba5a:cdef Note: Remove leading zeros Replace the longest set of 4 zeros replacing with 2 colons If there are two the same size Replace the 1st set Non-removed sets of 4 zeros shortened to 1 zero

a) If your firm has an 18-bit network part and you need at least 16 subnets, what must your subnet part size be? b) How many hosts can you have per subnet?

a) 5 bits If the network part is 18 bits, that leaves 14 bits for subnets and hosts. 4 bits would give 16-2 subnets or only 14, so I will need 5 bits which will allow for 32-2 or 30 subnets. b) (2^9 - 2) =510 hosts If I have 5 bits for subnets then I will have 9 bits for hosts (14-5). 2 ^ 9 is 512 -2 leaves 510 hosts per subnet.

a) In cellular technology, what is a cell? b) What is a cellsite? c) What are the two functions of the MTSO?

a) A cell is a small geographical region served by a cellsite b) A cellsite is the equipment at a site near the middle of each cell, that contains a transceiver and supervises the operations of all cellphones c) MTSO connects cellular customers to one another and to wired telephone users, and also oversees all cellular calls

For the following Routing Table. a) Which rows match 172.30.17.6? b) Which rows match 60.168.7.32? c) Which rows match 128.171.17.13?

a) Row 13 (default) matches 172.30.17.6. b) Row 12 and 13 (default) match 60.168.7.32. c) Row 1, 7, and 13 (default) match 128.171.17.3.

Which of the following is NOT one of the three categories of PBX services?

advanced services

In SNMP, the manager communicates directly with a(n) ________.

agent

VoIP ________ uses the Internet Protocol for transmission.

always

Tor provides the sending host with ________.

anonymity

IPsec protects ________ layer content.

application

Which of the following affects what cellular throughput an individual user will receive?

both being in a moving car and being far from the cellsite

An MTSO ________.

both controls cellsites in a cellular system and links mobile users to wired telephone customers

When a message arrives at a Tor router, the router ________.

both decrypts the arriving message and erases its memory of the source address

A DHCP server provides a client with ________.

both one or more IP addresses for it to use and the IP address of one or more DNS servers

An IaaS owns ________.

both servers and application programs

Which reduces traffic more when sending long files?

caching

Express the mask /18 in dotted decimal notation. a) 255.0.0.0 b) 255.255.0.0 c) 255.255.255.0 d) None of these

d) None of these

If your subnet part is 7 bits long, how many subnets can you have? a) 128 b) 256 c) 512 d) None of these

d) None of these

Companies get second-level domains from ________.

domain registrars

Pinging is to send ICMP ________ messages to the target host.

echo request

One-bit fields are called ________ fields.

flag

In TDM, time is first divided into brief periods called ________.

frames

In cellular technology, G stands for ________.

generation

A ring topology is attractive because it brings ______.

greater reliability

Creating a new VM is ________.

instantiation

Router ports are called ________.

interfaces

In e-mail, SSL/TLS provides ________.

link encryption

Amplitude modulation uses two _______ levels.

loudness

The primary applications architecture is ________.

neither TCP/IP nor OSI

A border router connects different IP ________.

networks

If any row other than the default row matches an IPv4 address, the router will ________.

never choose the default row

Traffic shaping reduces traffic by ________.

preventing or limiting undesirable traffic from entering the network

Compression reduces traffic by ________.

reducing redundancy in the data

Because of the curvature of the earth, microwave systems that must travel over long distances need ________.

repeaters

For 100,000 addresses, which will have fewer rows?

routing table

IaaSs own ________.

servers

Cells are used in cellular telephony to provide ________.

service for more customers

SIP is a ________ protocol for VoIP.

signaling

In TDM, a voice conversation gets the same ________ in each ________.

slot, frame

An internal router connects different IP ________.

subnets

In Tor, ________ can read the content of the message delivered to the destination host.

the last Tor router

Speech codecs ________.

translate human voice signals into digital signals for transmission

Which of the following receive rights of way for transmission beyond sites?

carriers