Networking Concepts Quiz
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Questions and Answers

What is the primary goal of a conditional GET request in HTTP?

  • To reduce the size of the object transmitted
  • To request additional data from the server
  • To modify the existing cached object on the server
  • To avoid transmitting an object if it is already up-to-date in the cache (correct)

What is the effective data rate to browsers over the access link if the cache hit rate is 0.4?

  • 0.6 Mbps
  • 0.9 Mbps (correct)
  • 1.2 Mbps
  • 1.54 Mbps

Which FTP port is designated for control connections?

  • Port 21 (correct)
  • Port 443
  • Port 80
  • Port 20

Which of the following is NOT a component of electronic mail?

<p>File Transfer Protocol (FTP) (D)</p> Signup and view all the answers

What is the impact of having a cache hit rate of 0.4 on total delay?

<p>Increases total delay as more requests go to origin servers (C)</p> Signup and view all the answers

What must a browser and web server maintain during their interaction?

<p>Past history (state) (A)</p> Signup and view all the answers

What happens to the TCP connection in a non-persistent HTTP?

<p>It is closed after sending one object (D)</p> Signup and view all the answers

What is the main characteristic of persistent HTTP?

<p>Multiple objects can be sent over a single connection (C)</p> Signup and view all the answers

If a client or server crashes during an HTTP interaction, what must be addressed?

<p>Inconsistencies in their views of state (A)</p> Signup and view all the answers

What is the first step when a user enters a URL in a non-persistent HTTP scenario?

<p>The HTTP client initiates a TCP connection (B)</p> Signup and view all the answers

When a client receives a response message containing an HTML file, what happens next?

<p>The client parses the HTML file for additional objects (D)</p> Signup and view all the answers

What indicates a successful establishment of a TCP connection between client and server?

<p>The client receives a response message from the server (A)</p> Signup and view all the answers

What is the primary function of SMTP in mail protocols?

<p>Delivery and storage to the receiver's server (B)</p> Signup and view all the answers

Which of the following best describes IMAP?

<p>Offers advanced features including manipulation of stored messages (A)</p> Signup and view all the answers

During the authorization phase in the POP3 protocol, what is the purpose of the client command 'user'?

<p>To declare the username for login (D)</p> Signup and view all the answers

Which command in the POP3 protocol is used to delete a message?

<p>dele (D)</p> Signup and view all the answers

What does the server response '+OK' indicate in the POP3 protocol?

<p>The command was processed successfully (D)</p> Signup and view all the answers

What distinguishes IMAP from POP in mail protocols?

<p>IMAP supports message manipulation on the server (D)</p> Signup and view all the answers

In the context of email protocols, what does the command 'list' do in POP3?

<p>It lists the message numbers available on the server (C)</p> Signup and view all the answers

Which of the following is NOT a feature of the POP protocol?

<p>Direct manipulation of messages stored on the server (C)</p> Signup and view all the answers

Which HTTP-based service is mentioned in the context of email access protocols?

<p>Gmail (A)</p> Signup and view all the answers

What does the status code 200 indicate in an HTTP response?

<p>Request succeeded and the requested object is included. (A)</p> Signup and view all the answers

What response can be expected when the server responds with a 404 status code?

<p>The requested document was not found on the server. (D)</p> Signup and view all the answers

Which HTTP status code should be used when a requested object has permanently moved?

<p>301 Moved Permanently (A)</p> Signup and view all the answers

When sending a GET request using telnet, which line is necessary for the request to be complete?

<p>Host: cis.poly.edu (D)</p> Signup and view all the answers

What occurs when a server sends a 400 Bad Request status code?

<p>The request message is not understood by the server. (D)</p> Signup and view all the answers

How do you establish a TCP connection to a web server for HTTP requests?

<p>Using telnet on the appropriate server port. (A)</p> Signup and view all the answers

What must you do after typing in the GET HTTP request in telnet?

<p>Hit the carriage return twice to send the full request. (A)</p> Signup and view all the answers

What is indicated by the status code 505 in an HTTP response?

<p>The specified HTTP version is not supported by the server. (D)</p> Signup and view all the answers

What would typically be included following a 301 Moved Permanently status code?

<p>The new location of the requested object. (B)</p> Signup and view all the answers

The average request rate from browsers to origin servers is 15 requests per second.

<p>True (A)</p> Signup and view all the answers

In a caching scenario with a 1.54 Mbps access link, the access link utilization is 100%.

<p>False (B)</p> Signup and view all the answers

Increasing the access link speed is a cost-effective solution in every situation.

<p>False (B)</p> Signup and view all the answers

The LAN utilization is 15% in the given caching example.

<p>True (A)</p> Signup and view all the answers

Total delay in a network is the sum of Internet delay, access delay, and LAN delay.

<p>True (A)</p> Signup and view all the answers

An IP address and port number are sufficient for uniquely identifying a process running on a host.

<p>False (B)</p> Signup and view all the answers

File transfer applications require 100% reliable data transfer.

<p>True (A)</p> Signup and view all the answers

UDP provides flow control, making it suitable for applications requiring low latency.

<p>False (B)</p> Signup and view all the answers

Web document applications require no data loss and are considered elastic in terms of throughput.

<p>True (A)</p> Signup and view all the answers

Real-time audio and video applications can tolerate some loss of data.

<p>True (A)</p> Signup and view all the answers

TCP is characterized as an unreliable transport protocol that does not require connection setup.

<p>False (B)</p> Signup and view all the answers

Interactive games require low delays to be effective and can function with few kilobits per second of throughput.

<p>True (A)</p> Signup and view all the answers

DNS operates as a centralized database for all hostname to IP address translations.

<p>False (B)</p> Signup and view all the answers

If a local name server cannot resolve a name, it contacts a root name server.

<p>True (A)</p> Signup and view all the answers

Mail server aliasing involves using one canonical name to represent multiple mail servers.

<p>True (A)</p> Signup and view all the answers

Load distribution in DNS helps scale the system by mapping a single name to multiple IP addresses.

<p>True (A)</p> Signup and view all the answers

A distant centralized database is preferred for efficient DNS operation.

<p>False (B)</p> Signup and view all the answers

Root DNS servers are only contacted when a local name server has the IP address already cached.

<p>False (B)</p> Signup and view all the answers

The process for obtaining the IP address of a domain involves multiple queries to different DNS servers.

<p>True (A)</p> Signup and view all the answers

Traffic volume can lead to performance issues if DNS does not utilize load distribution.

<p>True (A)</p> Signup and view all the answers

An authoritative name server is contacted only if the root server knows the name mapping.

<p>False (B)</p> Signup and view all the answers

In a client-server approach, the time to distribute a file to N clients increases linearly in N.

<p>True (A)</p> Signup and view all the answers

The server must upload at least two copies of the file in a P2P approach to ensure distribution.

<p>False (B)</p> Signup and view all the answers

The maximum upload rate is the sum of the server upload rate and the sum of all peers' upload capacities.

<p>True (A)</p> Signup and view all the answers

The time required to send one copy of a file is calculated as $F/us$.

<p>True (A)</p> Signup and view all the answers

In a client-server model, each client's minimum download time depends on their upload rate.

<p>False (B)</p> Signup and view all the answers

In the P2P distribution method, the time to distribute to N clients can be calculated using $DP2P > max{F/us,F/dmin,NF/(us + Sui}$.

<p>True (A)</p> Signup and view all the answers

Client download times in a P2P approach are independent of the download rates of the peers.

<p>False (B)</p> Signup and view all the answers

The server needs to send multiple copies sequentially in a client-server approach to all clients.

<p>True (A)</p> Signup and view all the answers

The aggregate download capability of clients in a P2P system can decrease overall distribution time.

<p>True (A)</p> Signup and view all the answers

Match the following concepts related to caching with their explanations:

<p>Cache hit rate = Percentage of requests served by the cache RTT = Round Trip Time for a request to the server and back Access link utilization = Percentage of the link's capacity being used LAN utilization = Utilization rate of the Local Area Network</p> Signup and view all the answers

Match the following network performance issues with their consequences:

<p>High access link utilization = Increased response time Low LAN utilization = Inefficient use of resources Insufficient cache = Higher number of requests to origin servers Increased RTT = Longer delays in data retrieval</p> Signup and view all the answers

Match the following types of caching scenarios with their potential benefits:

<p>Local caching = Reduces access link utilization Using a fatter access link = Improves data transfer rates Caching by ISP = Enhances user experience for repeated requests P2P file sharing = Distributes load across multiple users</p> Signup and view all the answers

Match the following average rates in the caching example with their definitions:

<p>Avg object size = Size of data typically requested from the server Avg request rate = Number of requests sent to the server per second Avg data rate to browsers = Speed at which data is delivered to end users Access link rate = Maximum throughput of the connection to the internet</p> Signup and view all the answers

Match the following network elements with their descriptions:

<p>Origin server = The main server hosting the content Client = The end-user device requesting data Access link = The link connecting the institution to the internet LAN = Local network within an institution</p> Signup and view all the answers

Match the following application protocols with their primary usage:

<p>SMTP = Email transmission HTTP = Web communication FTP = File transfer Telnet = Remote terminal access</p> Signup and view all the answers

Match the following HTTP status codes with their meanings:

<p>200 = OK 404 = Not Found 301 = Moved Permanently 400 = Bad Request</p> Signup and view all the answers

Match the following application types with their corresponding transport protocols:

<p>Web applications = TCP Streaming multimedia = TCP or UDP Internet telephony = TCP or UDP Email = TCP</p> Signup and view all the answers

Match the following protocols with their layer in the OSI model:

<p>SMTP = Application Layer TCP = Transport Layer IP = Network Layer Ethernet = Data Link Layer</p> Signup and view all the answers

Match the following application characteristics with their descriptions:

<p>Stateless = Server retains no client information Encrypted connection = Secure data transmission Cleartext passwords = Risk of exposure during transmission Endpoint authentication = Verifying the identities of communicating parties</p> Signup and view all the answers

Match the following services with their reference protocols:

<p>Web page delivery = HTTP Email retrieval = POP3 File transfer = FTP Domain name resolution = DNS</p> Signup and view all the answers

Match the following web page components with their types:

<p>HTML file = Text document JPEG image = Picture Java applet = Interactive application Audio file = Sound recording</p> Signup and view all the answers

Match the following types of HTTP connections with their characteristics:

<p>Non-persistent HTTP = At most one object sent over TCP connection Persistent HTTP = Multiple objects sent over single TCP connection TCP connection close = Requires multiple connections for multiple objects Single TCP connection = Connection is kept open for subsequent requests</p> Signup and view all the answers

Match the steps of a non-persistent HTTP request with their sequence:

<p>Initiate TCP connection = HTTP client sends request message Form response message = HTTP server receives request message Close TCP connection = HTTP server sends response message Display HTML file = HTTP client parses received HTML</p> Signup and view all the answers

Match the following protocols with their roles:

<p>HTTP = Application-layer protocol for web communication TCP = Transport protocol ensuring reliable connections FTP = File transfer protocol between client and server SMTP = Protocol for sending email messages</p> Signup and view all the answers

Match the following terms with their definitions:

<p>State in HTTP = Past history that must be maintained Inconsistent state = Views of client/server may differ post-crash HTTP response = Message containing requested object HTTP request message = Indicates client wants an object</p> Signup and view all the answers

Match the types of content with their associated HTTP methods:

<p>GET = Requesting a resource from the server POST = Submitting data to be processed PUT = Updating an existing resource DELETE = Removing a resource from the server</p> Signup and view all the answers

Match the following concepts related to efficiency in HTTP with their explanations:

<p>Caching = Storing responses to reduce future requests Load balancing = Distributing requests across multiple servers Compression = Reducing size of data to speed up transfer Pre-fetching = Loading data before it is requested</p> Signup and view all the answers

Match the components of a typical HTTP transaction with their order:

<p>Client sends request = Server accepts connection Server forms response = Client displays content Client displays content = Server closes TCP connection Server sends response = Client parses HTML</p> Signup and view all the answers

Match the following causes of state inconsistencies in HTTP with their descriptions:

<p>Client crash = Loss of request in progress Server crash = Inability to serve client requests Network failure = Interruption of data transfer Timeouts = Expiration of connection without data exchange</p> Signup and view all the answers

Match the following networking layers with their appropriate functions:

<p>Application Layer = User interfaces and applications Transport Layer = End-to-end communication and reliability Network Layer = Routing and forwarding of packets Link Layer = Physical addressing and data frames</p> Signup and view all the answers

Match the following HTTP response status codes with their meanings:

<p>200 = Request succeeded, requested object later in this msg 301 = Requested object moved, new location specified later in this msg 400 = Request msg not understood by server 404 = Requested document not found on this server</p> Signup and view all the answers

Match the following terms related to HTTP requests with their descriptions:

<p>GET = An HTTP method used to request data from a server POST = An HTTP method used to send data to a server PUT = An HTTP method used to update an existing resource on a server DELETE = An HTTP method used to remove a resource from a server</p> Signup and view all the answers

Match the following commands with their function in an HTTP interaction using telnet:

<p>telnet = Opens a TCP connection to a specific port GET = Sends a request for a specific resource from a server Host = Specifies the domain to which the request is sent HTTP/1.1 = Defines the version of the HTTP protocol being used</p> Signup and view all the answers

Match the following HTTP status codes with their situations:

<p>200 = The request was successful 301 = Resource has permanently moved to a new URL 400 = The server cannot process the request due to client error 505 = The server does not support the HTTP protocol version used in the request</p> Signup and view all the answers

Match the following HTTP request components with their descriptions:

<p>Request line = Specifies the method, resource, and HTTP version Headers = Provide additional information in the request Body = Contains data to be sent to the server (if applicable) Request message = Entire message sent from client to server including all components</p> Signup and view all the answers

Match the following HTTP client actions with their sequence:

<p>Open TCP connection = Establishes a communication channel to the server Send GET request = Requests specific data from the server Wait for response = Client pauses to receive the server's reply Display response = Shows the returned data to the user</p> Signup and view all the answers

Match the following HTTP version phrases with their appropriate codes:

<p>HTTP/1.1 = Version commonly used for web traffic HTTP/2 = Introduced multiplexing for improved performance HTTPS = Secure version of HTTP using SSL/TLS HTTP/0.9 = An early version of HTTP with limited capabilities</p> Signup and view all the answers

Match the following outcomes with their corresponding status codes:

<p>200 = Success 301 = Moved Permanently 404 = Not Found 400 = Bad Request</p> Signup and view all the answers

Match the following telnet commands with their action:

<p>GET /~ross/ HTTP/1.1 = Initiates a request for the specified resource Host: cis.poly.edu = Identifies the host to the server Hit carriage return twice = Signals the end of the request Observing response = Analyzes the HTTP response from the server</p> Signup and view all the answers

Flashcards

Caching Example

Using a local cache to store frequently accessed data, reducing latency and improving performance.

Conditional GET

A technique to avoid transmitting data if a cached copy is up-to-date.

FTP

File Transfer Protocol; a standard network protocol used to transfer files between computers.

FTP Control Connection

Connection used for commands and control in FTP.

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FTP Data Connection

Separate connection used for the actual file transfer in FTP.

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Non-persistent HTTP

A type of HTTP connection where a single TCP connection is used to send only one object between client and server, then the connection is closed.

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Persistent HTTP

A type of HTTP connection where multiple objects can be sent over a single TCP connection, which remains open between client and server.

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HTTP Request

A message sent by the HTTP client (browser) to the HTTP server to request an object (e.g., a webpage or image).

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HTTP Response

A message sent from the HTTP server to the HTTP client containing the requested object.

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TCP Connection

A network connection between the HTTP client (browser) and HTTP server to transfer messages.

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Application Layer

The layer in the network model dealing with protocols like HTTP, responsible for managing application-level communications.

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State Management

The process of maintaining the past history of the interactions between the client and server to ensure consistency during crashes or issues.

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HTTP Response Status Code

A numerical code that indicates the outcome of an HTTP request from a client to a server.

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200 OK

The HTTP status code indicating a successful request, and the requested object follows.

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301 Moved Permanently

HTTP status code indicating the requested object was moved, with a new location specified.

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400 Bad Request

HTTP status code meaning the server cannot understand the request message.

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404 Not Found

HTTP status code signifying the requested resource is unavailable on the server.

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505 HTTP Version Not Supported

HTTP status code indicating the server does not support the HTTP version in the request.

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GET HTTP Request

An HTTP method used to request a resource from a server.

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Telnet

A network protocol used to establish a connection to a remote host.

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HTTP port 80

The standard port number used by web servers for communication.

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Mail access protocol

A protocol used to retrieve emails from a mail server.

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POP3: Authorization phase

The initial phase of POP3 connection where the client (your email program) verifies your username and password with the server.

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POP3: Transaction phase

The phase after successful authorization where the client can interact with the server to retrieve, delete, or manage emails.

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POP3: list command

Used to list all available email messages on the server.

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POP3: retr command

Used to retrieve the contents of a specific message.

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Caching

Storing copies of frequently accessed data closer to users to improve performance and reduce load on the origin server.

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Client-Server Architecture

A system where a client requests data from a server, which processes and sends the data back.

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Internet Delay

The time it takes for data to travel from the origin server to the user's browser.

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Access Link Rate

The speed at which data can be transferred between the local network and the wider internet.

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Local Cache Impact

Installing a local cache can improve performance by serving content locally, reducing latency.

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Open Protocol

A protocol defined in specifications (RFCs) and available to the public, allowing for interoperability between different systems.

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Proprietary Protocol

A protocol owned and controlled by a specific company or organization, often restricted to their own systems.

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Transport Service Requirements

The specific needs of applications in terms of data reliability, throughput, timing, and security.

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TCP (Transmission Control Protocol)

A reliable transport protocol that provides flow control, congestion control, and connection-oriented data transfer. Ensures data arrives in order and without loss.

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UDP (User Datagram Protocol)

An unreliable transport protocol that does not offer flow control, congestion control, or connection-oriented data transfer. Offers fast but less reliable data transfer.

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Why Use UDP?

Despite its unreliability, UDP is useful for applications that can tolerate data loss or prioritize speed over absolute reliability, such as streaming media.

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DNS: Hierarchical Database

DNS, or Domain Name System, is a hierarchical database that maps human-readable domain names to numeric IP addresses. It utilizes a distributed structure of servers to efficiently resolve names.

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DNS: Root Name Servers

Root name servers are the highest level in the DNS hierarchy. They provide starting points for name resolution by directing queries to the appropriate top-level domain (TLD) servers.

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DNS: Resolution Process

Resolving a domain name involves a series of queries. A client first queries a local name server, which then contacts the root server to find the appropriate TLD server. The resolution continues until the server holding the specific domain name's IP address is reached.

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Single Point of Failure

A single point of failure (SPOF) is a component within a system that, if it fails, will cause the entire system to fail. With DNS, a single root server failure could disrupt worldwide name resolution.

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Load Distribution

Load distribution refers to distributing traffic across multiple servers to prevent a single server from becoming overloaded. It's essential for improving website performance and reliability.

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Replicated Web Servers

Replicated web servers involve multiple servers running the same service or website. This redundancy mitigates the impact of server failures and improves performance by allowing for load distribution.

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Host Aliasing

Host aliasing allows multiple domain names or hostnames to point to the same IP address. This is useful for providing alternate access points or simplifying user experience.

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Mail Server Aliasing

Similar to host aliasing, email server aliasing allows multiple email addresses to be forwarded to a single inbox. This simplifies email management and reduces spam.

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Distant Centralized Database

A centralized database, often located far from users, can pose challenges due to increased latency and potential maintenance issues. This can impact performance and reliability.

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Peer Upload/Download Capacity

The maximum rate at which a peer can upload or download data. It's a limited resource, impacting file distribution performance.

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Server Upload Capacity

The maximum rate at which the server can send data to peers. It's a crucial factor in file distribution time.

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Peer Download Capacity

The maximum rate at which a peer can receive data from other peers or the server. It influences how quickly a file is received.

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File Distribution Time: Client-Server

The time it takes to distribute a file to N clients using a traditional client-server approach. It's determined by the server's upload capacity, network bandwidth, and the slowest client's download rate.

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File Distribution Time: P2P

The time it takes to distribute a file to N clients using a peer-to-peer network. It's determined by the server's upload capacity, the slowest client's download rate, and the aggregate upload capacity of all peers.

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How does P2P affect distribution time?

In a P2P network, file distribution time is influenced not only by the server's upload capacity but also by the combined upload capacity of all participating peers. This can significantly reduce overall distribution time as more peers contribute.

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Client-Server vs. P2P: Distribution Time

In client-server networks, distribution time increases linearly with the number of clients due to the server's limited capacity. In P2P networks, distribution time also increases linearly with the number of clients, but the combined upload capacity of peers helps mitigate this.

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Scaling File Distribution

P2P networks handle large-scale file distribution more efficiently than client-server models because peers contribute their upload capacity to the system. This leads to improved performance as the number of clients increases.

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P2P Advantages

Peer-to-peer networks offer advantages like improved scalability, reduced server load, and faster file distribution. This is because peers contribute their upload bandwidth, creating a distributed network.

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HTTP: Stateless

HTTP servers do not maintain information about past client requests. Each request is treated independently.

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HTTP: Client-Server

HTTP communication follows a client-server model. Clients (e.g., browsers) send requests to servers (e.g., web servers), which respond with requested data.

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Web Page Components

A web page comprises various objects, including HTML files, images, applets, or audio files. These objects are linked together and accessible through URLs.

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URLs

Uniform Resource Locators (URLs) identify and locate specific objects on the web. They include the hostname and path name, pointing to the object's location on the server.

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TCP Connection in HTTP

HTTP uses TCP to establish a reliable connection between the client and server. TCP ensures data arrives in order and without loss.

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What are the benefits of persistent HTTP?

Persistent HTTP improves efficiency by reducing the overhead of establishing and closing multiple TCP connections, leading to faster downloads. It is particularly beneficial when downloading multiple related objects from the same server.

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What is the difference between persistent and non-persistent HTTP?

Persistent HTTP keeps the TCP connection open for multiple objects, while non-persistent HTTP closes it after each object is sent. Persistent HTTP is generally more efficient, while non-persistent is simpler.

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Why is state management important in HTTP?

State management ensures that both the client and server have consistent information about the state of their interactions, preventing inconsistencies or errors when one crashes.

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Telnet to Web Server

Using Telnet to establish a TCP connection to a web server, allowing you to send and receive data.

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Study Notes

Chapter 2: Application Layer

  • The chapter outlines the fundamentals of application layer protocols in computer networking.
  • PowerPoint slides are freely available for educational purposes.
  • Users are asked to mention the source and copyright when using or posting the slides online.
  • The goal is to understand protocols used in popular applications, their implementation, transport layer service models, client-server and peer-to-peer paradigms, and how to create network applications with a socket API.
  • Various network applications such as email, web browsing, messaging, remote login, file sharing, games, and streaming video are discussed.
  • Applications are built on top of end systems without the need for software on network core devices.
  • Two common application architectures are described; client-server and peer-to-peer(P2P).
  • Client-server architecture is characterized by always-on servers with persistent IP addresses and clients that may be intermittently connected with dynamic IP addresses. They do not communicate directly with each other.
  • For P2P applications there is no always-on server. End systems act as both client and server and communicate directly. It is self-scalable and involves complex management.
  • Processes within a host communicate via inter-process communication(IPC) defined by the operating system. Hosts communicate by exchanging messages.
  • Sockets are used as analogous to doors, messages are sent to a socket at the receiving process.
  • Applications need identifiers (IP address and port numbers) to properly receive messages from hosts.

Second Topic Subtitle

  • Web and HTTP:
  • Web pages are composed of multiple objects (HTML, images, applets, audio).
  • The base HTML file references other objects.
  • URLs are used to address objects.
  • HTTP is a hypertext transfer protocol for Web applications.
  • It uses TCP, client requests objects, the server sends the objects in response.

Third Topic Subtitle

  • HTTP overview (continued);
  • HTTP is 'stateless'
  • The server does not retain information about past client requests.
  • Different types of HTTP connections exist, non-persistent and persistent. The persistent connection allows multiple objects to be sent over a single TCP connection.
  • HTTP request messages have a request line (GET, POST, HEAD commands), headers, and a blank line between header and body.
  • HTTP response messages comprise a status line, headers, and a blank line separating headers from the body.
  • Some HTTP response status codes are 200 OK, 301 Moved Permanently, 400 Bad Request, 404 Not Found, 505 HTTP Version Not Supported.

Fourth Topic Subtitle

  • Uploading form input:
  • POST method uploads form inputs to the server within the entity body.
  • URL method uses GET uploads input in the URL field of the request line.

Fifth Topic Subtitle

  • Method Types
  • HTTP/1.0 supports GET, POST, and HEAD methods.
  • HTTP/1.1 builds on 1.0, adding PUT and DELETE. Methods specify types of actions to be performed on the requested resource.

Sixth Topic Subtitle

  • Cookies
  • cookies are used by web sites for session state management, authorization, shopping carts, and recommendations, and other features.
  • Cookies have four components: a header line in the response message, a header line in the request message, a cookie file stored on the user's host, and a backend database.

Seventh Topic Subtitle

  • Web Caches (Proxy server)
  • Caches assist in returning client requests without involving the origin server, reducing response time and traffic.
  • Typical caches are installed through ISP.

Eighth Topic Subtitle

  • Conditional GET
  • Caches can copy content and specify date, which helps in determining whether a cached copy is up to date.
  • If-Modified-Since: is used to check if a cached version is up to date; if not updated, the server returns a "304 Not Modified" code instead of the object.

Ninth Topic Subtitle

  • FTP: File Transfer Protocol
  • FTP transfers files between a remote host and a client.
  • It uses a client-server model, where clients initiates the transfer.
  • FTP uses separate control and data connections. The control connection manages commands and the data connection transfers the data.

Tenth Topic Subtitle

  • Electronic Mail (email)
  • Three major components: user agents (mail readers), mail servers, and simple mail transfer protocol (SMTP).
  • SMTP handles transferring email messages between mail servers.
  • The SMTP process involves three phases: handshaking, message transfer, and closure.

Eleventh Topic Subtitle

  • Mail Access Protocols
  • Mail access protocols (POP3, IMAP) are used by mail clients to retrieve mail from mail servers. POP3 downloads and deletes, while IMAP keeps messages on the server with additional features for managing message organization.

Twelfth Topic Subtitle

  • Socket Programming
  • Sockets are used in client/server applications to facilitate communication.
  • UDP sockets provide unreliable datagram transfer, while TCP sockets provide reliable byte-stream transfer. UDP requires no handshaking, uses IP destination addresses and port# which is useful for broadcasting, while TCP requires handshaking between client and server for a connection to be established before data transfer.

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Chapter_2_V6.3.pdf

Description

Test your knowledge on essential networking concepts such as conditional GET requests in HTTP, FTP control connections, and the effects of cache hit rates on data transfer. This quiz challenges your understanding of electronic mail components and total delay implications in network communications.

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