MIS405 Exam 1
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Measurement table for speed:
. Kilobits per second; kbps; 1,000 bits . Megabits per second; Mpbs; 1,000,000 bits . Gigabits per second; Gbps; 1,000,000,000 bits . Terabits per second; Tbps; 1,000,000,000,000 bits
What is the Encapsulation/Decapsulation process as they are sent from one host across two routers to another host?
....
Decode the Decimal IP Address into Binary: 10.150.25.30
00001010.10010110.00011001.00011110
What are the five layers of TCP/IP-OSI architecture?
1. Physical 2. Data Link 3. Internet 4. Transport 5. Application
Encode the Binary IP Address into Decimal: 00001010.10010110.00011001.00011110
10.150.25.30
In a coffee shop, there are 5 users. Two are actively sending or receiving at the moment. The rated speed of the access point is 6 Gbps. Its aggregate throughput is 5 Gbps. What is the individual throughput?
2.5Gbps
What is a connection/connection-oriented protocol?
A connection in which the two sides (hosts) first agree to communicate and then agree to stop communicating at the end
What do most firms actually use instead of a standard TCP/IP architecture?
A hybrid TCP/IP-OSI architecture , which combines OSI
What is a TCP segment?
A message in TCP. We call it this because each segment carries a segment (fragment) if the application message is too long
What is configuration? Where is it done?
A policy-based rule set that determines how forwarding should be done It is done in the control function
What is a connectionless protocol?
A protocol in which packets are transported over the network without a connection being established Book definition: A connection in which there is no need to have a live connection before transmitting a message; i.e: sending an email. You just send it
What is Overprovisioning?
Adding much more capacity than needed so that peaks become rare and brief
What is individual throughput?
Aggregate throughput divided by the number of active users at the moment
In a coffee shop, there are 10 people sharing an access point with a rated speed of 2 Gbps. The throughput is half the rated speed. Several people are downloading. Each is getting an average of 100 Mbps. How many people are using the Internet at that moment?
All 10 Aggregate throughput = 1 Gbps, 1 Gb = 1,000,000,000 bits, each user is getting 100 Mbps so 100 x 1,000,000 = 100,000,000, 1,000,000,000 / 100,000,000 = 10
TCP/IP is the _________ while TCP and IP are the _________
Architecture Standards
What is a zero day attack?
Attacks that exploit vulnerabilities that have not yet been discovered by software vendors
What makes TCP a reliable protocol?
Connection-oriented sessions; this is different from error checking. If a packet is lost it goes to the next one instead of backpeddling and slowing down process
Is HTTP a connection or connectionless protocol?
Connectionless
How does a Software-Defined Network work and how does it have an advantage over traditional networks?
Each device is stripped of the control function so that the control function can be centralized on the SDN server. Not only does this reduce hardware costs but it permits instant configuration even amongst multiple devices. Control agility is highly increased
What is social engineering (in terms of malware)?
For when there is no vulnerability; users are tricked through the means of: . phishing: attacks that appear to be real to a group of people such as customers of a bank . Spear Phishing: phishing but with a more specific target such as a few individuals . Going on a website and being tricked into installing malware
What is the specific function of the Transport layer of the TCP/IP-OSI Architecture?
Governs aspects of end-to-end communication between two hosts that are not handled by the internet layer. These standards allow hosts to work together even if the computers are two different vendors. Handles message fragmentation
What is the specific function of the Application layer of the TCP/IP-OSI Architecture?
Governs how two applications work with each other, even if they are from different vendors
What is the specific function of the Internet layer of the TCP/IP-OSI Architecture?
Governs transmission of packets across an internet, typically by sending them through several routers across a route
What is the broad function of of Application, the fifth layer of the TCP/IP-OSI Architecture?
Interoperability of application programs
What makes a protocol reliable?
It correct errors
What does the Control function do?
It is a policy-based reconfiguring of network devices.
What other QoS Metric is there to consider?
Jitters: A time related QoS Metric that measures the average variability in the latency between successful packets. Jitters do not affect most applications but can be very noticeable in streaming media
What is a single mode fiber?
Long range, no modal dispersion, one source emitting a signal but is more expensive than multimode fiber to buy and install
What is a trojan horse?
Malware that replaces an existing file by taking it's name, making it hard to detect because it appears legitimate. It cannot propagate itself, it must be delivered to the computer by hacker or through other malware
How do network managers deal with peak demands where demand exceeds capacity?
Overprovisioning, Prioritizing Traffic, QoS guarantees, and Traffic Shaping
After propagation, malware might execute _____ which intends to do what?
Payloads Cause damage
Which MTP management strategy is acceptable for latency tolerant traffic?
Prioritizing Traffic
What are the considerations of Overprovisioning?
Pro: Requires no additional management labor Con: Expensive in terms of transmission costs
What are the considerations for prioritizing traffic?
Pros: Delayed traffic will get through after a brief delay, limited additional cost (routers, switches, line etc.) Cons: Requires ongoing management and labor which drives up costs
What are the considerations for QoS guarantees?
Pros: Protected Traffic will always get through Cons: Unprotected traffic gets whatever is left over which makes things worse for all traffic, If reserved capacity is not used by protected traffic it is not available to other traffic
What are the considerations for Traffic Shaping?
Pros: Reduces overall costs, satisfies corporate needs because staff can not access unwanted traffic (torrents websites, youtube etc.), with unwanted traffic blocked there is plenty of room for desired traffic Cons: Can typically be blocked with a VPN, tends to make people unhappy
What is QoS guarantees?
Reserving capacity on each switch, router, transmission line, etc. for protected traffic
What is an example of a Layer 3 (Internet) device?
Router
What is the TCP three-way handshake? (Be able to draw this out for the exam
SYN, SYN/ACK, ACK 1. Host A (the client in the HTTP exchange) initiates communication by transmitting a TCP Synchronization segment to Host B, requesting to start a connection 2. Host B send back a SYN / ACK segment. The SYN indicates Host B is willing to begin communication. The ACK is an acknowledgement of Host A's SYN 3. Host A then acknowledges Host B's SYN/ACK and servers can now communicate *** FIN (Final) is sent to close the session
What is Prioritizing Traffic?
Sending higher priority traffic (i.e: delay intolerant traffic such as voice) through first
What is a virus?
Small pieces of code that attach themselves to legitimate programs, making them difficult to detect. When the program executes, the virus infects other parts of the computer. Viruses can also self-propagate to other computers through means of email, software downloads, social networks etc.
How do software vendors fix vulnerabilities and why is malware still an issue after they fix it?
Software vendors release "patches" but users do not always install patches promptly or at all
What is the purpose of layering?
Specialization in design. If layering is done well, one layer can change without requiring the other layers to
What are the QoS metrics that we discussed in class?
Speed: Transmission Speed in bits per second Errors: Percentage of incorrect bits (measure for physical layer) or packets (measure for internet layer) Availability: Percentage of time network is available to users Latency: Time Delay in Packet Delivery, Measured in Milliseconds
What is a worm?
Stand-alone malware programs that do not have to attach themselves to legitimate programs that usually spread like viruses, however, in some cases a vulnerability will allow worms to infect another computer with no human interaction
What is an example of a layer 2 (Data Link device)?
Switch
What does the forwarding function do?
Switches arriving frames back out or routes arriving packets back out. Forwards based on the control function's rule set
What is control agility?
The ability to rapidly change how the network operates when conditions change
What is throughput?
The speed that you actually receive. Sometimes much lower than rated speed. This is the only thing that is actually relevant to networking professionals
What is rated speed?
The speed the standard or the carrier specifies
What is aggregate throughput?
The throughput available to all users on a shared access point. i.e: a router at a coffee shop
What is the specific function of the Data Link layer of the TCP/IP-OSI Architecture?
To govern the transmission of frames across a single switched network. This is typically done by sending sending them through several switches across the data link. Data Link standards also govern frame organization, timing constraints, reliability, and tranmission of frames
What is the specific function of the Physical Data layer of the TCP/IP-OSI Architecture?
To govern transmission between devices. Example of a physical layer device: computer, tablet, phone etc.
The IETF Standards Architecture is named after it's two main initial standards. What are these?
Transmission Control Protocol / Internet Protocol (TCP/IP)
What is the broad function of of Physical and Data Link, the first two layers of the TCP/IP-OSI Architecture?
Transmission across a single network
What is the broad function of of Internet and Transport, the third and fourth layers of the TCP/IP-OSI Architecture?
Transmission across an internet
What is Traffic Shaping?
Tries to prevent occasional traffic peaks by reducing traffic allowed into the network so that traffic that cannot get in cannot cause traffic peaks
What are the different types of malware (that we learned about)?
Viruses, worms, trojan horse
What does malware exploit?
Vulnerabilities, which are security flaws in a program
What makes a protocol unreliable?
When there is no provision for the retransmission of last or damaged messages; HTTP is unreliable for this reason. It is like sending a text message
When should you measure errors?
When traffic is high so that it is possible to gain an adequate understanding of error rate risks
Why are traditional networks now at a disadvantage?
Whenever policy changes are made, configuration must be done manually on the control function. Traditionally, the rule set rarely changed but today the rule set changes frequently so a new way to configure devices is needed; control agility is quite limited
What are quality of service metrics?
quantitative measures of network performance that define how well a network is working an providing services
This is not always the case, but a connection/connection-oriented protocol tends to be _____ while a connectionless protocol tends to be _____
reliable unreliable
What is a multimode fiber?
shorter range, has modal dispersion, has thick core diameter, multiple sources emitting a signal
