EXAM3

client initiates, server responds

network interface card. either wifi or ethernet

ethernet is a bus network. Ethernet listens to see if the wire is busy. Then if it's not busy it will send the info on the bus. T or F

A repeater. Will extend ethernet networks and broadcast anything that is sent to it right back out.

A more sofisticated Hub that connects hubs together. Will learn where to send specific information based on the most frequent routes. Still on LAN and deals with frames.

devices that create the "internet" which spans Wide Area Networks. Handles IP adresses and TCP. Also bridges the gap between incompatible protocols. allow Point-to-Point phone connections

protocol that defines internet addressing. Is unreliable. store and forward. out of order on its own. ROGERS DEFINITION: provides the basic naming scheme and a delivery mechanism that can send packets, known as datagrams, from one Internet host to any other host.

protocol that adds reliability to IP. Ensures delivery of packets and provides in order delivery. ROGERS DEF: It provides reliable full duplex (bidirectional) connections between processes

Clients and Servers are Processes. NOT machines (hosts) T or F

Some wires and a small box

A chunk of bits that is sent from one host to another ON LAN

Extends IP slightly just so that packets/datagrams can be sent from process to process instead of host to host

Client calls Sockets interface, sockets calls kernel for TCP/IP stuff (NOT A QUESTION JUST TYPE T) this is how they are layered.

unsigned 32-bit integer. stored in the structure called in_addr which is in network byte order.

What is the function that converts byte order host to network short

What is this notation? (128.2.194.242)

You convert dotted decimal to hex by taking each number between the dots and converting it to hex. 128.2.194.242 = 0x80 02, C2, F2 T or F

What command shows the dotted decimal address of each NIC

a human-friendly representation of an IP address

What is the organization that deals with domain names (only highlevel such as tntech and .edu)

Mapping of domain names is maintained by

Command to get ip address from domain name

Command that gets hostname of local host (other than just saying "localhost")

A connection between a pair of processes is called

A connection where data can flow in both directions at the same time is called

An end point of a connection

Contains an internet address and 16 bit integer port

Port that is assigned automatically by the kernel when the client makes a connection request

Port that is permanently associated with a service

How to create a socket (server and client use this) #include <sys/types.h> and <sys/socket.h>

What function attempts to establish an internet connection (client) #include <sys/types.h> and <sys/socket.h>

What function asks the kernel to associate the server's socket address with the socket descriptor? (server) #include <sys/types.h> and <sys/socket.h>

What function tells the OS that a server is listening on a socket and to start queing connections. (server) #include <sys/types.h> and <sys/socket.h>

What function takes the queued connection request and fills in the socket address and returns a socket that can be used to communicate? (server) #include <sys/types.h> and <sys/socket.h>

TAKE THIS TIME TO MEMORIZE THIS CLIENT CODE:
int main() {
int sock;
struct sockaddr_in servAddr;
struct hostent *hp;
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0 {
error */
}
bzero((char *) &servAddr, sizeof(servAddr));
servAddr.sin_family = AF_INET;
hp = gethostbyname(”www.csc.tntech.edu”);
memcpy(&servAddr.sin_addr, hp->h_addr, hp->h_length);
servAddr.sin_port = htons(PORT);
if (connect(sock, &servAddr, sizeof(servAddr)) < 0) {
error */
}
if (send(sock, msg, strlen(msg), 0) < 0) { error */ }
close(sock);
return 0;
}

MEMORIZE THIS SERVER CODE
int sockfd, newsockfd, clilen;
struct sockaddr_in cli_addr, serv_addr;
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
error */
}
memset((void *) &serv_addr, 0, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
serv_addr.sin_port = htons(PORT);
if (bind(sockfd, (struct sockaddr *) &serv_addr,
sizeof(serv_addr)) < 0) { error */ }
listen(sockfd, 5);
for (;;) {
clilen = sizeof(cli_addr);
newsockfd = accept(sockfd,
(struct sockaddr *) &cli_addr, &clilen);
if (newsockfd < 0) { error */ }
handleConnect(newsockfd);
}

What opens a socket descriptor into a file stream

What does HTTP stand for

Typically with web servers, the response to a request is in this declaritive language that describes how something should look

Java and c++ are ____ which means they have instructions on how to do something

What is MIME type (ex: text./html or image/png)

Content that is simply fetched from disk and given to a client

Content that is an exectutable file that must be ran for the client

What does URL stand for?

How do you format arguments sent by URL?

How do you write a http request?

Whats the most recent Version of HTTP

What format is a HTTP response in?

200 = OK 301= Moved permentatnly 400= bad request 403=Forbidden 404=not found 501= not implemented 505= html not supported

content-type: ___

content-length: ___

How are spaces shown in arguments

- accessing slow I/O devices
- interacting with humans
- Reducing latency by defering work
- servicing multuple network clients
- computing in parallel on multicore machienes

Each logical control flow is a process maintained by kernel. Harder to communicate between them (seperate address space). simplest way maintained through for and exec.

difficult to share state information, tend to be slower becayse of inter process communication and context switching

run in the context of a single process, scheduled by kernel, share virtual address space, unique thread ID, smaller context than processes,

void *thread(void *vargp);
int main() {
pthread_t tid;
pthread_create(&tid, NULL, thread, NULL);
pthread_join(tid, NULL);
exit(0);
}
void *thread(void *vargp) {
Thread routine */
printf("Hello, world!\n");
return NULL;
}
MEMORZE THIS

what creates a thread

How to reap a thread

how to detach a thread (make it release all memory instead of reaping)

This is a form of concurrent programming where applications explicitly schedule their own logical
flows in the context of a single process.
Logical flows are modeled as state machines that the main program explicitly transitions from state to
state as a result of data arriving on file descriptors

Each thread has its own:
• Thread context, including a unique integer thread ID (TID)
• Stack and stack pointer
• Program counter
• General-purpose registers, and
• Condition codes

Each thread shares the context of the process its ran in

Pthread_create returns

Each thread share global variables

When two threads are attempting to change a shared global variable at the same time

the compiler will attempt to apply the operation in one atomic machine code instruciton

the property that only one process is allowed in a critical section at a
time

pthread_mutex_t mut;
pthread_mutex_init(&mut, 0);
pthread_mutex_lock(&mut)
//do something with a shared variable
pthread_mutex_unlock(&mut);