For the multiple choice questions, place your answer in the box provided under e
ID: 3770720 • Letter: F
Question
For the multiple choice questions, place your answer in the box provided under each question. For example:
In wireless networking, one challenge involves unexpected collisions from two separated stations when physical obstructions get in the way of signal propagation. This is called:
signal to noise ratio
signal attenuation
hidden terminal problem
In wireless networking, another challenge involves unexpected collisions from two separated stations when distance causes signal to fade. This is called:
signal to noise ratio
signal attenuation
hidden terminal problem
CDN stands for
Collision Detection Network
Content Delivery Network
Channel Division Nesting
Content Detection Network
Select the item that describes why video content is stored and positioned in peering points or in multiple locations making up a CDN to serve clients:
Content is often stored in one location for clients to view and download; the other locations provide backup copies of the content.
Voice and video streams are stored separately in different locations and then streamed separately until the client merges the stream together to produce an acceptable play back.
The closer content is stored to the clients that view it, the quicker it will download.
CDNs are not used for video; only voice
_____ is a hop-by-hop protocol involving hosts and routers, while _______ is an end-to-end protocol involving only the two end-stations.
FTP, HTTP
IP, TCP
WiFi, WiMax
FDM, TDM
Expand the acronym RTP: __________________________________________
Expand the acronym SSL: ___________________________________________
Expand the acronym ARP: __________________________________________
Expand the acronym TCP: __________________________________________
Expand the acronym IP: ___________________________________________
Choose the item that describes RTP or an attribute of the RTP protocol:
RTP can extend UDP with port numbers, IP addresses, payload type identification
SIP and H.323 both can use the RTP protocol
RTP is used by Voice and Video applications
RTP stands for Realtime Transport Protocol
All of the above
Once client playout of stored stream video begins, playback must match original timing. Network delays can be variable, though, so video applications use ______ to compensate:
the RTP protocol
client-side buffering
DNS
Jitter
When using Dynamic, Adaptive Streaming over HTTP (DASH), a server does the following:
relies on the DNS to provide a nearby source of content
divides video files into multiple chunks, each encoded at multiple rates
periodically measures one-way delay and/or throughput to inform requests
re-encodes raw data on the fly to match requirements
When using Dynamic, Adaptive Streaming over HTTP (DASH), a client does the following:
relies on the DNS to provide a nearby source of content
divides video files into multiple chunks, each encoded at multiple rates
periodically measures one-way delay and/or throughput to inform requests
re-encodes raw data on the fly to match requirements
For the next 5 questions, fill in the blank using one of the 9 words or phrases found below.
CSMA/CA CSMA/CD CSMD/CP
CDMA FDMA TDMA
Token Passing OFDMA FDDI
802.11 WiFi LAN protocols make use of ____________ for channel access.
802.3 Ethernet LAN protocols make use of ____________ for channel access.
Channel partitioning based on frequencies is known as ___________.
Channel partitioning based on time slots is known as ___________.
_______ is a technique that allows simultaneous transmissions using unique codes.
The two fundamental functions that routers perform are:
Forwarding and routing
Forwarding and broadcasting
Forwarding and managing link state
Forwarding and reflecting
A common IP network queue discipline, in which the traffic is queued and serviced in the order in which it arrives, is called ___________ queuing.
FIFO queuing
weighted fair queuing
token bucket queuing
round robin queuing
A queue discipline in IP networks in which there are multiple queues and each class gets a weighted amount of service during each cycle is called ___________
priority queuing
weighted fair queuing
token bucket queuing
round robin queuing
IPv4 uses ________ bit addresses while IPv6 uses _________ bit addresses.
32, 64
32, 128
64, 128
128, 256
When considering IPv4 addressing, a subnet mask tells us how many of the 32 bits are associated with the ____________ and how many are available for use by ___________.
Network, Hosts
Routers, Switches
Protocols, Applications
None of the above
When considering IPv4 addressing, a “/30 subnet” has space for _______ hosts when setting aside the all-0 host address for the network and the all-1 host address for broadcasts.
30
4
2
0
When it comes to common symmetric key cryptographic approaches, ___________ is a stronger and more modern encryption standard than the older ______________:
AES, FTP
AES, DES
SSL, TLS
monoalphabetic, polyalphabetic
For the next 7 questions, fill in the blank using one of the 15 words or phrases found below.
IPSec VPN SSL Public Key
Private Key Symmetric Key Block Cipher
authentication session hijacking confidentiality
message integrity block-cipher certificate authority
A facility providing encryption and authentication services, frequently for web applications, and implemented as a layer in between the Application layer and TCP: ____________________
This approach is often used by companies with multiple sites to provide security at the network layer: _________________
In a ____________, the message to be encrypted is processed k bits at a time. The cipher uses a one-to-one mapping to map the k-bits of cleartext to a new k-bits of ciphertext.
A security goal in which only a sender and intended receiver “understand” a message contents: ______________________
A security goal in which sender and receiver want to ensure a message has not been altered (in transit, or afterwards) without detection: ____________________________
____________________ is a kind of cryptography in which two communicating parties use the same cryptographic key.
A cryptographic approach in which a public encryption key is known to all and a private decryption key is known only to receiver is called ____________________ cryptography.
Alice wants to encrypt a message she is sending to Bob. She does so with Bob’s ___________________ key, knowing that Bob can decrypt the message with his ______________key.
public, private
private, public
symmetric, secret
None of the above
Alice wants to digitally sign a message she is sending to Bob. She does not need to encrypt the message. She creates a ________________ of her message and encrypts that with her ___________________ key, and concatenates the result with the original message. Bob will then verify her “signature” by making use of Alice’s ______________key.
MAC, public, private
Hash, private, public
decoy, symmetric, secret
None of the above
For a network that carries both Voice over IP traffic from IP Phones, as well as Data network traffic from laptops and desktops, a network designer might configure __________ to separate and expedite voice traffic.
FIFO queuing
802.1Q VLANs with 802.1p priority
Jumbo frames on the local LAN
802.11i and 802.11ac
A common way to use standards-based VoIP protocols is to use __________ for carrying the call audio, and ____________ for call setup and tear-down.
RTCP, DASH
Skype, NAT
HTTP, FTP
RTP and UDP, SIP
To recover from packet loss, given the small tolerable delay between original transmission and playout, VoIP doesn’t rely upon retransmission. Instead it uses _________________ which involves sending additional bits to allow recovery without retransmission.
Secure Sockets Layer (SSL)
The Session Initiation Protocol (SIP)
Forward Error Correction (FEC)
Weighted Fair Queuing (WFQ)
Choose the item below that best describes flow control:
Flow control involves sender/receiver speed matching, to help ensure that a sender won’t overwhelm a receiver by sending packets at too high a rate.
Flow control resends packets at a lower rate when packets are dropped along the path between a sender and a receiver.
Flow control is performed by link layer switches to throttle broadcast traffic so receiving hosts do not get overloaded.
Flow control limits each TCP connection to its fair share of network bandwidth.
Select the item below that describes an attribute of a link-layer switch:
Link-layer switches are self-learning.
Link-layer switches examine the ports embedded in the transport layer header of a packet
Link-layer switches forward packets based on their destination IP addresses
Link-layer switches forward packets based on their source IP addresses
VLANs can allow a single switch to act as ___________
An IP router
A mobile-IP node
Multiple virtual switches
All of the above
When configuring VLANs on multiple switches, any single VLAN can appear across multiple switches through the configuration of VLAN ___________
Spanning Tree
DHCP
Mobile IP
Trunk Ports
For the final 5 questions, you are asked to design a network to meet the following requirements:
A new network is required to connect a new building on campus with (2) wings.
Each wing will require a wired network with (100) wired computers in each.
The wired network in each wing will require (4) managed Ethernet switches
Each wing will also require a wireless network with up to (100) IP addresses for mobile users.
The wireless network in each wing will require (4) managed 802.11 wireless access points
You are told to use either (1) or (2) IP subnets for this new building. Your choice.
If one subnet, the network will also require one additional address for the subnet router interface. If two subnets, the network will require two additional addresses for router interfaces.
The network manager asks you to assign IP addresses from the range:
192.168.50.0 to 192.168.51.255 (which is 512 total addresses)
How many total IP addresses will be needed for computers and mobile users? ___________
How many total IP addresses are needed for Ethernet switches, wireless access points, and router interfaces for this new network? Show how you arrived at that number. _________________________________________________________________________
How many subnets will you use? Describe how you chose, and how you will use them:
__________________________________________________________________________________
__________________________________________________________________________________
Show your network address(es) including subnet size(s)
__________________________________________________________________________________
Show your broadcast address(es)
__________________________________________________________________________________
Explanation / Answer
1. In wireless networking, one challenge involves unexpected collisions from two separated stations when physical obstructions get in the way of signal propagation. This is called:
Hidden Terminal Problem
2. In wireless networking, another challenge involves unexpected collisions from two separated stations when distance causes signal to fade. This is called:
signal attenuation
3. CDN stands for
Content Delivery Network
4. Select the item that describes why video content is stored and positioned in peering points or in multiple locations making up a CDN to serve clients:
The closer content is stored to the clients that view it, the quicker it will download.
5. _____ is a hop-by-hop protocol involving hosts and routers, while _______ is an end-to-end protocol involving only the two end-stations.
IP, TCP
6. Expand the acronym RTP: _______Real-time Transport Protocol
Expand the acronym SSL: __________Secure Sockets Layer
Expand the acronym ARP: _________Address Resolution Protocol
Expand the acronym TCP: _________Transmission Control Protocol
Expand the acronym IP: ___________Internet Protocol
7. Choose the item that describes RTP or an attribute of the RTP protocol:
RTP can extend UDP with port numbers, IP addresses, payload type identification
SIP and H.323 both can use the RTP protocol
RTP is used by Voice and Video applications
RTP stands for Realtime Transport Protocol
All of the above
8. Once client playout of stored stream video begins, playback must match original timing. Network delays can be variable, though, so video applications use ______ to compensate:
client-side buffering
9. When using Dynamic, Adaptive Streaming over HTTP (DASH), a server does the following:
divides video files into multiple chunks, each encoded at multiple rates
10. When using Dynamic, Adaptive Streaming over HTTP (DASH), a client does the following:
periodically measures one-way delay and/or throughput to inform requests
11. 802.11 WiFi LAN protocols make use of __ CSMA/CA ___for channel access.
802.3 Ethernet LAN protocols make use of ___CSMA/CD___ for channel access.
Channel partitioning based on frequencies is known as __ FDMA__.
Channel partitioning based on time slots is known as __ TDMA __.
__CDMA__ is a technique that allows simultaneous transmissions using unique codes.
12. The two fundamental functions that routers perform are:
Forwarding and routing
13. A common IP network queue discipline, in which the traffic is queued and serviced in the order in which it arrives, is called ___________ queuing.
FIFO queuing
14. A queue discipline in IP networks in which there are multiple queues and each class gets a weighted amount of service during each cycle is called ___________
weighted fair queuing
15. IPv4 uses ________ bit addresses while IPv6 uses _________ bit addresses.
32, 128
16. When considering IPv4 addressing, a subnet mask tells us how many of the 32 bits are associated with the ____________ and how many are available for use by ___________.
Network, Hosts
17. When considering IPv4 addressing, a “/30 subnet” has space for _______ hosts when setting aside the all-0 host address for the network and the all-1 host address for broadcasts.
4
18. When it comes to common symmetric key cryptographic approaches, ___________ is a stronger and more modern encryption standard than the older ______________:
AES, DES
19. A facility providing encryption and authentication services, frequently for web applications, and implemented as a layer in between the Application layer and TCP: __session__
This approach is often used by companies with multiple sites to provide security at the network layer: ____IPSec___
In a __block-cipher___, the message to be encrypted is processed k bits at a time. The cipher uses a one-to-one mapping to map the k-bits of cleartext to a new k-bits of ciphertext.
A security goal in which only a sender and intended receiver “understand” a message contents: ______confidentiality______
A security goal in which sender and receiver want to ensure a message has not been altered (in transit, or afterwards) without detection: ________integrity________
____Symmetric Key _______ is a kind of cryptography in which two communicating parties use the same cryptographic key.
A cryptographic approach in which a public encryption key is known to all and a private decryption key is known only to receiver is called ____Public Key_____ cryptography.
20. Alice wants to encrypt a message she is sending to Bob. She does so with Bob’s ___________________ key, knowing that Bob can decrypt the message with his ______________key.
public, private
21. Alice wants to digitally sign a message she is sending to Bob. She does not need to encrypt the message. She creates a ________________ of her message and encrypts that with her ___________________ key, and concatenates the result with the original message. Bob will then verify her “signature” by making use of Alice’s ______________key.
Hash, private, public