IT 403 Final Exam
How does the user see the network?
As a utility - only cares that it works (not how)
How does TCP work?
- Breaks data up into packets - Puts a header on each packet (which contains its sequence # and the sequence number of the next expected packet) - Makes sure that all of the data arrives to at its destination
Relationships in a relative path.
- Parent: always a folder (up, ../) - Child: folder (down, name of folderr/filename) - Sibling: folder or a file (over, name of file or folder) - Grandparent: (up up, ../../)
How does the internet work?
- user connects to a local ISP, which connects to other ISP's creating a regional network - made of many LAN's and WAN's - need a NIC card, software, and cabling to connect
HTML for numbered list (ordered list)
<ol> <li> Item 1 </li> <li> Item 2 </li> <li> Item 3 </li> </ol>
HTML for paragraph
<p>....</p>
HTML for bold
<strong>......</strong>
HTML for bulleted list (unordered list)
<ul> <li> Item 1 </li> <li> Item 2 </li> <li> Item 3 </li> </ul>
What is packet switching?
A method of sending data in which the data is broken up into packets, sent, and reassembled at the destination.
What is SNA?
A networking model
What is layering?
A networking model
What is IXP (or IX)?
A point where content deliver networks exchange data with an ISP. It's an autonomous system.
Are IP addresses static or dynamic?
Dynamic (generally). They're dynamically assigned by DHCP when one is needed
What's the difference between guided and unguided media?
Guided media's signals go through solid media (copper, fiber) while unguided media propagates freely.
What does HTML stand for?
Hypertext Markup Language
What is IP?
Internet Protocol - logical addressing and routing
What does the title do and can names be repeated?
It's what's displayed in the tab and they should only be used once per site
What is a LAN?
Local Area Network - a network that connects computers within a limited area such as a school or office
Can you have headers outside of the body?
NO
Is there ambiguity in protocols?
NO - it's intolerable
Commands for traversing directories.
Siblings (aka "Over"): Name-of-file
What is a de jure standard and an example of one?
Something that has gone through a standard's body, which made it official. TCP/IP is a de jure standard
Syntax vs. simantics
Syntactically correct content compiles correctly. Semantically correct content is written with elements that convey the meaning to the browser that you're using them for. Important for web crawlers and screen readers.
What is the scheme in a URL?
Tells the browser how to retrieve the resource ex: http, ftp, sftp, mailto
What is the identifier in a URL?
Tells the browser where to go get the resource (may include a path)
How do image elements work?
They go out into the world and replace the image element with the image once its rendered.
What is a positive aspect of using relative URL's?
They make it easier to maintain a site
What are anchor elements and what are they used for?
They're hyperlinks. Use to link to other websites or email addresses.
Before networking standards, how was information between different brands of machine sent?
Through a gateway (worked like a translator/ converter)
What is the hierarchy of network service providers look like?
Tier 1 - nation or worldwide network Tier 2 - regional networks Tier 3 - local ISP's
What does URL stand for?
Universal Resource Locator
What is the peer to peer file transfer model?
What's needed?: - IP addresses that the data is coming from and going to - The file - An application on both computers that can communicate
What is a WAN?
Wide Area Network - connects computers that are further apart, made of many connected LAN's
Are elements case sensitive?
YES - always lowercase
Does TCP require IP to work?
Yes
What is the internet?
a network of interconnected networks
In HTML, words such as id, href, src, and alt may be added within an element's start tag in order to provide a browser with additional information about that element. What is such an element called
attribute
What is a network?
combination of hardware, software, and cabling which together allow multiple computing devices to communicate with each other
What are the required pieces of an HTML page?
doctype, html heading, head, title (in head), meta (in head), body
What protocol is most specifically involved in making the World Wide Web possible?
http(s)
What does a network engineer do?
network engineer takes the wires from the wire panel into the server
What is the subdomain of a URL?
www
How does the peer to peer file transfer model work?
- SFTP sends the file - TCP breaks up the file into packers - IP figures out where the packets need to go - Ethernet send the packets - TCP puts the packets back together Example: skype
What are some of the earliest networks?
- Telegraph (physical wires ran across the country, on which currents were sent) - Phone (each phone was wired to a central location, the central location connected people to one another) - party lines (some families shared lines, only one could use it at a time - at one point central locations had operators connect people to each other
Setting permissions/ access privileges on a site.
- There are 3 types of access: specify, read, write, execute. - There are three groups to set for: user, group, world. - Common values: 644 (readable by all, editable by user), 755 (readable by all, writable by user, executable for all).
How does IP work?
- figures out where the data is going, puts the destination and source address in a header **Does no error recovery (that's part of TCP's job!)
What are tier 3 ISP's and how do they work?
- local ISP's - many of these - closest to the customer
What are tier 2 ISP's and how do they work?
- regional networks - <100 in US - pays to connect to one or more tier 1 provider
What are tier 1 ISP's and how do they work together?
- very few of them (<20 in US) - backbone of the internet - they'll carry one another's traffic when one is overloaded or broken - don't charge one another - they treat each other as equals - each tier 1 has many tier 2 customer nets
Parent (aka "Up"):
../
Grandparent (aka "Up" "Up")
../../
What pieces in the OSI model correspond to each piece in the TCP/IP model?
1. Application 7. Application 6. Presentation 5. Session 2. Transport 4. Transport 3. Internetwork 3. Network 4. Network Interface 2. Data Link 1. Physical Link
What are the pieces of the TCP/IP networking model?
1. Application (HTTP) 2. Transport (TCP) 3. Internetwork (IP) 4. Network Interface (ethernet)
What are the pieces of the TCP/IP networking model?
1. Application (HTTP) (Armadillos) 2. Transport (TCP) (typically) 3. Internetwork (IP) (interact) 4. Network Interface (ethernet) (nicely indoors))
HTML for a comment
<!-- this is the comment -->
What is a container element?
An element that has both an opening and closing set of <>, with information between them
What is an empty element?
An element that has only one set of <> and all of the element's info is between that one set of <> In best practice, they end with a terminating slash ex: </br>, <img.../>
How does the server administrator see the network?
As a utility - only cares that it works (not how)
What are character entities and what are some examples?
Characters that have a syntactical meaning in HTML. In the form &char. Includes: - < (less than) - > (greater than) - " (quote) - &apos (apostraphe) - & (&) -   attaches two words with a space between them (used if you want the words on the same line)
What are files made up of?
Collections of bits
What is XML?
Computer Language
What are the two types of elements?
Container and empty
What are block level elements?
Elements with space around them. Ex: <p>, <div>, <h1>
How (in what form) does a network send data?
In packets (groups of bits). This breaks large amounts of data into small pieces, and allows easier data recovery.
What steps does a packet go through to get to a customer?
Local ISP → tier 3 ISP → Tier 2 ISP → tier 1 ISP → tier 1 ISP → Tier 2 ISP → Tier 3 ISP → local ISP **this is only one example, sometimes there are extra jumps
What is the purpose of peering points?
Locations where (Tier-1 or Tier-2) networks are connected for the purpose of exchanging traffic
What is the difference between a logical and physical port?
Logical port is a software port - port 8080 Physical port is something a wire would plug into - an outlet
What is the domain/ host name of a URL?
Name and extension
Children (aka "Down")
Name-of-folder/filename
What piece of hardware do all devices need to be able to talk to any other devices?
Network (NIC) card
What elements can be within a list?
Only list items.
What do the TCP/IP and the OSI network models demonstrate?
The division of labor - each piece has a function
What is peering?
Tier 1 ISP's often work together by swapping traffic at specific points. They don't charge one another to do this.
What is TCP?
Transmission Control Protocol - breaks data up into chunks and error recovery
What makes UDP different from TCP?
UDP doesn't maintain a connection, doesn't guarantee delivery, or preserve the sequences. TCP provides a connection between 2 entities to regulate flow check errors and has forward acknowledgement with its sequencing.
Can you nest lists?
You can only nest a list inside of another list, if the nested list is within a list element. (lists within lists must be in a list element)
What does an electrician do?
runs the physical cable from wall plates into wiring panels
What is the basic layout of an HTML page?
<!DOCTYPE html> <html lang = "en"> <head> <title> hello, I'm the title </title> <meta charset = "utf 8" /> </head> <body> </body> </html>
HTML for a link to an email address
<a href = "[email protected]"> shows up as on the page (normally a name)</a>
HTML for an link to a website
<a href = "this_is_where_the_link_goes.com"> This is the text that you would click to follow the link</a>
HTML for line break
<br/> **empty element
HTML for a divider
<div>.....</div> ***creates a new line ***used when there's not a better option
HTML for definition/dictionary lists (pairs of items, term and definition)
<dl> <dt> term 1 </dt> <dd> def. 1 </dd> <dt> term 2 </dt> <dd> def. 2 </dd> </dl> **not every dd needs a dt or vise versa
HTML for italics
<em> ........ </em>
HTML for headings
<h#>.......</h#> **# can be any int between 1-6
HTML for an image
<img src = "link_to_img.jpg" width = "#" height = "#" alt="Text that could show up in place of the img" />
What is a de facto standard?
A standard that's developed by individual companies and are generally just used (not official). Windows systems are used as a standard in many offices and homes.
What's the difference between absolute and relative URL's?
Absolute URL's can be accessed from anywhere. Relative URL's are in reference from another location.
What is IXP (or IX)?
Content deliver networks, autonomous systems
Who (what group) is in charge of the TCP/IP networking model?
Internet Engineering Task Force
Does IP require TCP to work?
No
Is modern HTML both structural and presentational?
No - HTML is structural, CSS is presentational
What is the purpose of best practices?
To build skills that are applicable to both HTML5 and XHTML
What is the purpose of protocols?
To have interoperability
What is the purpose of a network and how does it work?
To move bits around using binary (1's and 0's) indicated by voltage
Anatomy of a URL
http://www.example.com http == scheme www == sub-domain example == name .com == extension example.com == domain name www.example.com == identifier
Types of communication and their pros/cons
human to human: - max flexibility and complexity - ambiguity is unavoidable human to device: - moderate flexibility and complexity - programming languages device to device: - minimal flexibility and complexity - no ambiguity == effiency
What is accidental network usage and what are some examples?
user doesn't even know that they're using a network ex: file access, printing services
What is intensional network usage and what are some examples?
user is aware that they're using a network ex: sending an email, going to a URL, upload/download
Can you nest div's?
yes! They're great for organizing, especially with id's
