Computer Networking and Application Layer Review

A set of 40 vocabulary flashcards covering key networking concepts, DNS, application/transport protocols, video streaming, and web architecture from lecture notes.

DNS (Domain Name Service)

An application layer protocol that provides mapping from human-preferred URLs to computer-preferred IP addresses, handles aliasing, and manages mail server associations.

IP Address (IPv4 Size)

A 32-bit numerical identifier associated with every URL on the Internet.

Root DNS Server

A top-level hierarchy DNS server containing canonical info about everything; acts as a contact of last resort and provides IP addresses for Top Level Domain servers.

Top Level Domain (TLD) Server

A DNS server responsible for top-level domain extensions such as .com, .edu, and .uk.

Authoritative DNS Server

A DNS server maintained by a registered organization or company that directs queries to the specific IP address of its hosts.

Local DNS Server

A DNS server provided by an ISP that sits outside the official hierarchy to cache responses and make queries faster.

Time to Live (TTL)

An expiration field included in every DNS resource record that specifies how long a record can be cached before it must be re-checked for updates.

DNS Type A Record

A DNS resource record where the Name field is a hostname and the Value field is its corresponding IP address.

DNS Type AAAA Record

A DNS resource record where the Name field is a hostname and the Value field is an IPv6 address.

DNS Type NS Record

A DNS resource record where the Name field is a domain (e.g., simmons.edu) and the Value field is the hostname of its authoritative name server.

DNS Type CNAME Record

A DNS resource record where the Name field is an alias hostname and the Value field is its canonical hostname.

DNS Type MX Record

A DNS resource record where the Name field is a domain and the Value field is the name of the associated SMTP mail server.

Iterative DNS Query

A DNS resolution method where the local ISP DNS server directly queries root, TLD, and authoritative servers step-by-step to obtain an IP address.

Recursive DNS Query

A DNS resolution method where the local DNS server requests the root server, which queries the TLD server, which queries the authoritative server, passing the final answer back down the chain.

Propagation Delay

The time required for a signal bit to cross a physical link, determined by the speed of sound or light.

Transmission Delay

The time required to push all signal bits of a message onto a link, described as how fast words are spoken out of a mouth.

ATNLP

An acronym representing the five layers of the Internet protocol stack: Application, Transport, Network, Link, and Physical.

Application Layer

The highest layer of the internet protocol stack that decides application needs and is directly interacted with by the user.

Client-Server Paradigm

An application architecture where an always-on server with a permanent IP address waits to be contacted by intermittently connected clients with dynamic IP addresses.

Peer-to-Peer (P2P) Paradigm

An application architecture with no central server where end systems communicate directly with each other to share files.

Mesh Network

A network structure using proprietary protocols where each device repeats what it hears to transmit messages across long distances.

Socket

The software interface through which a process sends and receives messages, described as a door or a place in memory where messages wait.

Process Identifier (Process ID)

The unique network identifier for a process, formed by combining an IP address and a port number.

Port 80

The standard port number designated for HTTP traffic.

Message Syntax

The structure or form of messages defined by an application layer protocol.

Message Semantics

The specific meaning of the fields and information contained inside protocol messages.

Data Integrity

A transport layer service guarantee confirming whether all data arrives intact at its destination.

Elastic Throughput

A network characteristic where data transfer speed can flexibly operate faster or slower than the transmission rate.

DASH Protocol

Dynamic, Adaptive Streaming over HTTP; a video protocol where the server divides video into chunks and re-encodes them at multiple bit rates and quality levels.

Content Distribution Network (CDN)

A distributed system of servers used by media services to distribute and stream video content efficiently to large numbers of users.

Enter Deep Strategy

A CDN deployment strategy that places server nodes deep inside local access networks near users worldwide for fast access.

Bring Home Strategy

A CDN deployment strategy that builds large server clusters in centralized locations of the internet with high traffic throughput.

Buffering

The requirement of storing a certain amount of video data locally before playback can begin.

TCP (Transmission Control Protocol)

A connection-oriented transport protocol that guarantees reliable transport, flow control, and congestion control.

UDP (User Datagram Protocol)

A connectionless transport protocol that provides fast, unreliable data transport without flow, congestion, timing, or throughput guarantees.

Host Name

The server identifier portion of a URL (e.g., login.motorcycles) that holds greater routing importance than the path name.

Path Name

The directory file path in a URL (e.g., /pictures/me.jpg) specifying a resource location on a server.

HTTP (Hypertext Transfer Protocol)

The primary application-layer protocol for the web, consisting of independent request and response messages.

Cookies

Text files stored on a user's computer that allow web servers to track user state across independent HTTP requests.

User Agent (Mail)

An application such as Thunderbird (also called a mail reader) that allows users to compose and read emails while storing a local copy of messages.