Transmission
Control
Protocol
(TCP)
1
2
Sending and receiving buffers
Stream of bytes
3
TCP segments
Segment N
Segment 1
H
H
Numbering:
Byte Number
Sequence Number
Data + Ctrl, Data, Ctrl (response) - Valid Sequence number
Acknowledge Number
4
TCP segment format
5
Control field
TCP Connections
✓ Connection Establishment
✓ Data Transfer
✓ Connection Termination
✓ Connection Reset
7
Connection establishment using three-way handshake
seq: 8000
UAPRS F
SYN
seq: 15000
ack: 8001
nd: 5000
U A P R S F rw
SYN + ACK
seq: 8000
ack: 15001
UAPRS F
rwnd: 10000
ACK
Means “no data” !
seq: 8001 if piggybacking
8
Data Transfer
Pushing data
Urgent data
Connection Termination
9
Connection termination using three-way handshake
10
Half-Close
11
STATE TRANSITION DIAGRAM
12
Simultaneous open
13
Simultaneous close
ex
14
WINDOWS IN TCP
Send window in TCP
15
Receive window in TCP
16
FLOW CONTROL
An example of flow control
17
ERROR CONTROL
Normal operation
18
Lost segment
19
Fast retransmission
20
Lost acknowledgment
21
Lost acknowledgment corrected by resending a segment
22
CONGESTION CONTROL
Slow start, exponential increase
23
Congestion avoidance, additive increase
24
TCP Taho
TCP Taho - Example
TCP Reno
TCP Reno - Example