Transport Layer

Question 1

Main purpose

Answer 1

Data is segmented and sent to destination device

Question 2

Multiplexing

Answer 2

Multiple apps use network at the same time

Question 3

Reliable delivery

Answer 3

Lost segments of data are resent so data is received complete

Question 4

Same order delivery

Answer 4

Ensures segments are reassembled into the proper order

Question 5

Flow control

Answer 5

Manages data delivery if there is congestion on the host

Question 6

Uses of TCP

Answer 6

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

Question 7

Uses of UDP

Answer 7

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

Question 8

Socket

Answer 8

IP address + port number

Ex. 192.168.1.20:80

Question 9

Well known port numbers

Answer 9

0 to 1023

Question 10

Netstat command

Answer 10

Lists protocols in use

Question 11

TCP headers contain…

Answer 11

Sequence numbers, order matters during reassembly

Question 12

TCP initial session

Answer 12

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

Question 13

Side note

Answer 13

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

Question 14

TCP session termination

Answer 14

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

Question 15

Expectational acknowledgement

Answer 15

Multiple segments can be sent before acknowledgement to avoid overhead

Question 16

Flow control

Answer 16

Adjusting rate of data flow between services in the session

Question 17

Window size

Answer 17

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

Question 18

More UDP

Answer 18

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

Question 19

Registered ports

Answer 19

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

Question 20

Dynamic or private ports

Answer 20

49152-65535; to client apps when initiating a connection

Question 21

Port number

Answer 21

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