1.3 Network Data Mangement

Question 1

What is NAS?

Answer 1

Network Application Software

Single or groupings of applications that control system functionality in a network.

Question 2

What are three common NAS applications?

Answer 2

Remote Terminal Applications
File Transfer Protocols
Ping

Question 3

What is a Remote Terminal Application?
What are three common types of RTA’s?

Answer 3

Allow users to access and manage remote devices on a client-server model.

Includes:

Secure Shell (SSH)
Telnet
SSL/TLS

Question 4

Describe Telnet. What is a disadvantage to Telnet?

Answer 4

Allows clients to remotely send commands to servers and network devices.

Commands are sent over plaintext with no encryption, which is a security risk.

Question 5

What is Secure Shell (SSH)

Answer 5

Allows clients to remotely send commands to servers and network devices but uses password and public key encryption.

Question 6

What is SSL?

Answer 6

SSL is Secure Sockets Layer:

Establishes a secure connection on an insecure network.

Your computer accesses a web server.
The web server gets an SSL certificate from the website to authenticate its identity.
The web server sends the SSL cert. to your computer.
Your computer tells the web server it trusts the website.
The web server acks and opens the connection.

Question 7

What is TLS?

Answer 7

Transport Layer Security:

Establishes secure connection on insecure network.

Supersedes SSL.

Similar to SSL but also encrypts the data.

Question 8

What is FTP?

Answer 8

File Transfer Protocol.

The protocol to transfer files over a TCP/IP network.

Uses client-server model.

Uses plaintext so it is not secure.

Question 9

What is Ping?

Answer 9

Tests the reachability of a host on an IP based network.

Sends ICMP echo request packets to the target and measures the round-trip time.

Question 10

What is Bandwidth Management?

Answer 10

Prevents unexpected drains on a limited bandwidth.

IPv6 has more native bandwidth control
IPv4 requires extra software and devices.

Question 11

What are the factors of Bandwidth Management?

Answer 11

Same as QoS.

Bandwidth
Throughput (packet loss)
Latency
Jitter

Question 12

What are some hardware solutions to bandwidth management?

Answer 12

Statistical multiplexing.
Throttling
Server segmentation
T Carrier
E Carier

Question 13

What is Statistical Multiplexing? (STDM)

Answer 13

Hardware solution to bandwidth management.

STDM = Statistical Time Division Multiplexing

Assigns time slots for transmitting. Reassigns empty slots to fill empty slots.

Question 14

What is Bandwidth Throttling?

Answer 14

Intentionally slowing or speeding internet service to minimize network congestion and prevent server crashes. Prevents a user from spamming the network.

Question 15

What is segmentation?

Answer 15

Breaking up a LAN into smaller broadcast domains.

AKA subnetting.

Question 16

What is a T Carrier?

Answer 16

A piece of hardware which carries digitized voice over time division multiplexed channels over a 4 wire circuit. Replaced by E-Carrier

Question 17

What is an E-Carrier

Answer 17

Hardware device which allows digital transmission of many simultaneous phone calls via TDM. Replaced by Ethernet.

Question 18

Describe TCP Congestion Control.

Answer 18

Senders increase packet rates until a packet is lost.

Tahoe and Reno algorithms are used to:

Increasing: test the network to determine whether the network can sustain a higher sending rate

Decreasing: react to congestion to minimize loss rate.

Question 19

Describe the ‘sliding window’ method for TCP congestion control.

Answer 19

The sender uses acknowledgements from the reciever to clock its data sending, to ensure there is a fixed amount of packets in flight at any given time.

Question 20

Describe Data Compression.

Answer 20

Encoding information to use fewer bits.

Question 21

What is Lossless data compresssion?

Answer 21

Identifying and eliminating statistical redundancy to reduce bits.

Question 22

What is Lossy data compression?

Answer 22

Removing unnecessary or less important information to reduce bits.

Question 23

What is Packet Shaping?

Answer 23

Delays flow of certain types of packets IOT prioritize certain applications.

Question 24

Describe a Token Bucket.

Answer 24

Tokens represent a group of bits or bytes.

A user request to send data reaches the bucket and if there are tokens in the bucket, the data goes through, using a token.. If not, the packet is dropped. The tokens are filled up at a refill rate.

Question 25

Describe Leaky Bucket

Answer 25

Packs are send through the bucket at a constant rate to smooth traffic.

Question 26

Describe Caching

Answer 26

Data is stored (usually on RAM) to allow faster call up for frequent requests. Helps latency and throughput.

Question 27

Describe Scheduling.

Answer 27

More bandwidth is given to certain types of traffic.

Eg. VOIP requires more bandwidth because it is more sensitive to congestion.

Question 28

Describe First Come, First Serve

Answer 28

Packets sent first are allowed through the network first. Fair algorithm that ensures starvation will not occur.

Question 29

Describe priority scheduling.

Answer 29

A network scheduler will prioritize packets based on priority flags or ports (not on data type)

Question 30

Describe Round Robin scheduling.

Answer 30

Everyone gets a turn to transmit in sequence. Fair, no starvation.

Can add dynamic weights to connections to implement priority.