Transport Layer Flashcards Preview

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Flashcards in Transport Layer Deck (21):
0

Main purpose

Data is segmented and sent to destination device

2

Multiplexing

Multiple apps use network at the same time

3

Reliable delivery

Lost segments of data are resent so data is received complete

4

Same order delivery

Ensures segments are reassembled into the proper order

5

Flow control

Manages data delivery if there is congestion on the host

6

Uses of TCP

Web browsers, email, file transfers; reliable delivery, connection oriented

7

Uses of UDP

DNS, VoIP, video streaming, TFTP, snmp, online games, RIP; uses datagrams

8

Socket

IP address + port number
Ex. 192.168.1.20:80

9

Well known port numbers

0 to 1023

10

Netstat command

Lists protocols in use

11

TCP headers contain...

Sequence numbers, order matters during reassembly

12

TCP initial session

1. Initiates process to create connection with destination, initial sequence value
2. Dest sends ack back
3. Client sends ack back and session is established

13

Side note

An individual server cannot have two services assigned to the same port number

14

TCP session termination

1. Send fin
2. Destination sends ack
3. Destination sends fin
4. Host sends ack
RST reset connections
PSH PUSH FUNCTIONS
URG Urgent pointer field significant

15

Expectational acknowledgement

Multiple segments can be sent before acknowledgement to avoid overhead

16

Flow control

Adjusting rate of data flow between services in the session

17

Window size

Number of bytes sent before an acknowledgement is sent; can also be controlled dynamically

18

More UDP

Reliability provided by the application layer; no guaranteed delivery of datagrams

19

Registered ports

1034-49151; user processes or applications dynamically selected as client source port

20

Dynamic or private ports

49152-65535; to client apps when initiating a connection

21

Port number

Address for various applications and services; servers have static port numbers, clients have dynamic port numbers