1. © 2003, Cisco Systems, Inc. All rights reserved.

2. Transport Layer Functionality
Module : TCP/IP
Transport Layer Functionality

3. Objectives
Correctly order the steps to establish a peer system connection
Identify the capsulation term at the layer of the TCP/IP stack
Define three components of a TCP header
Define two components of a UDP header
Correctly order the steps to establish a TCP connection
Lesson Aim
<Enter lesson aim here.>

4. Objectives (Cont.) Describe TCP acknowledgement of segments
Define the term TCP windowing
Identify three characteristics of a TCP port
Identify the steps to terminate a TCP connection
Lesson Aim
<Enter lesson aim here.>

5. Establishing a Connection
Host
Host
In a Connection
Lesson Aim
<Enter lesson aim here.>
TCP

6. Encapsulation Application Message Application Segment Transport
Lesson Aim
<Enter lesson aim here.>
Segment
Transport
Transport
Network
Packet
Network
Data link
Frame
Data link
Physical
Physical

7. Transport Layer Application Transport Network Data Link Physical
TCP (Transmission Control Protocol)
UDP (User Datagram Protocol)
Transport
Network
Data Link
Physical

8. TCP Header 16-Bit source Port 16-Bit Destination Port
32-Bit Sequence Number
32-Bit Acknowledgment Number
4-Bit Header Length
urg
ack
psh
rst
syn
fin
Reserved
16-Bit Window Size
Lesson Aim
<Enter lesson aim here.>
16-Bit TCP Checksum
16-Bit Urgent Pointer
Options
Data

9. Establish : 3-Way Handshake
Host A
Host B 1
Send SYN
(seq=100 ctl:syn) 2
Send SYN, ACK
(seq=300 ack=101 ctl:syn/ack)
Lesson Aim
<Enter lesson aim here.>
Established
(ack=301 ctl:ack) 3

10. Ending : 4-Way Handshake
Host A
Host B 1
Send FIN
(seq=100 ctl:fin) 2
Send ACK
(ack=101 ctl:ack)
Lesson Aim
<Enter lesson aim here.> 3
Send FIN
(seq=300 ctl:fin) 4
Established
(ack=301 ctl:ack)

11. TCP Simple Acknowledgment
Sender
Receiver
Send 1
Receive 1
Send ACK 2
Receive ACK 2
Send 2
Receive 2
Lesson Aim
<Enter lesson aim here.>
Send ACK 3
Receive ACK 3
Send 3
Receive 3
Send ACK 4
Receive ACK 4

12. TCP Windowing Sender Receiver Packet 3 is Dropped Window size = 3
Lesson Aim
<Enter lesson aim here.>
Window size = 2
Send 3
Window size = 2
Send 4
ACK 5
Window size = 2

13. UDP Header 16-Bit Source Port 16-Bit Destination Port
16-Bit UDP Length
16-Bit UDP Checksum
Lesson Aim
<Enter lesson aim here.>
DATA

14. Numbers F T P T E L N E T S M T P D N S T F T P S N M P R I P
Application Layer
Lesson Aim
<Enter lesson aim here.> 21 23 25 53 69
161
520
Port Numbers
Transport Layer
TCP
UDP

15. Summary
A user of the transport layer must establish a connection-oriented session with its peer system.
The data package looks different at each layer and at each layer the package goes by a different name.
The TCP header supplies information specific to the TCP protocol.
The UDP header supplies information specific to the UDP protocol.
TCP establishes a conversation using a three-way handshake.

16. Summary (Cont.)
A window is the number of data octets the sender is allowed to have outstanding without having received an acknowledgment.
TCP provides sequencing of segments with a forward reference.
TCP and UDP use ports to support multiple conversations between different networked devices.
TCP terminates the connection when the conversation ends.