Annex C07 Transport Layer

Question 0

Transmission Control Protocol (TCP)

Answer 0

Connection oriented protocol that incurs over twice the overhead of UDP IOT gain additional functionality

Provides:

- reliable delivery
- error recovery
- flow control
- congestion control
- ordered delivery
- connection establishment

Question 1

User Datagram Protocol (UDP)

Answer 1

Simple connectionless delivery method. Low overhead that works well with high bandwidth applications such as voice/video

Question 2

Command used to view ports being used on a PC

Answer 2

netstat

Question 3

Well Known Ports

Answer 3

Ports 0-1023 are reserved fro commonly used services and applications

21 FTP
23 Telnet
25 SMTP
80 HTTP
110 POP3
194 Internet Relay Chat (IRC)
443 Secure HTTPS

Question 4

Registered Ports

Answer 4

Ports 1024-49151, primarily ports assigned to applications that a user might decide to install.

1863 MSN Messenger
8008 Alternate HTTP
8080 Alternate HTTP

Question 5

Dynamic/Private Ports

Answer 5

Ports 49152-65535 are usually assigned dynamically to client applications as they initiate connections.

Question 6

How ports are used to establish a Transmission Control Protocol (TCP)

Answer 6

Client computer will use a unique and random port number as the source port (DYNAMIC) and request a web page from a server with the destination port of 80 (WELL KNOWN). The server will establish a connection with its source port being port 80 and the destination port being the same random port that originated the request for the web page

Question 7

Purpose of Order Delivery in relation to the functions of TCP

Answer 7

The SEQUENCE NUMBER is the next part of the TCP header field that we will examine, this provides the ordered delivery for TCP

Question 8

Sequence the steps of the TCP connection process in chronological order of the TCP 3 Way Handshake

Answer 8

1. Initiating client sends a synchronization “syn” segment requesting to start a comm session
2. The distant end responds with an acknowledgment of the synch request, a “syn.ack.” The distant end then sends its own syn request to initiate the flow of info back to the initiating client.
3. The initiating client responds with an “ack” of the distant end’s “synch”

Question 9

Reliable Delivery

Answer 9

TCPP provides reliable delivery on top of unreliable IP

Question 10

Window Size

Answer 10

Listed in the TCP header, is the amount of data that a source can transmit before an acknowledgment must be received.

Question 11

How TCP dynamically changes Window Size to overcome network congestion

Answer 11

Since the goal of TCP is to guarantee info delivery, the window size will flex to fit the quality of the connection and the bandwidth available.

Question 12

Flow Control

Answer 12

Flow control and window size together account for congestion control

Flow control (buffers)

Question 13

Match transport layer protocol to its header size

Answer 13

Fields of the TCP header enable TCP to provide connection oriented, reliable data comm

UDP header contains source port, destination port, UDP length, checksum, and data