0. Variety of TCP2－ Reno
Internet Engineering

1. Window Control of TCP Tahoe (Review)
Window Size
Maximum Window Size
Packet loss
Packet loss
Packet loss
ssthresh
(slow start threshold)
Times
Retransmission
Retransmission

2. TCP Reno : Fast Recovery
Problem of Tahoe: Window size fall extremely when packet loss (Window size fall into 1)
Determine packet loss by duplicate ACKs:
Replied ACKs are able to arrive  traffic congestion isn’t serious
Determine packet loss by time out
Replied ACKs are unable to arrive  traffic congestion is serious
Decrease Window size by a half
 Congestion Avoidance phase
fast recovery
Window size is decreased to 1Slow start phase
(Similar to Tahoe)

3. Window Size of Tahoe and Reno
Determine packet loss by duplicate ACKs:
Tahoe
Window Size 1
Reno
Window Size divided by 2
Determine packet loss by time out:
Tahoe
Window Size 1
Reno
Reno
Reno
Tahoe
Tahoe

4. TCP Window Control Summarize (Reno)
Window Size
Maximum Window Size
Packet loss
Packet loss
Packet loss
ssthresh
(slow start threshold)
Time
Retransmission
Retransmission

5. Inefficient case of TCP Reno
WS: Window Size
WS=8
WS=4
WS=5
Retransmission 1 18
Sender 1 2 3 4 5 6 7 8 1 9 10 11 11 12 13 14 15 16 17 19
Data
Packet
1 is dropped
ACK
Receiver 9 10 11 12 13 14 15 16 17 18 19 21
Next is 1
Retransmission 1
Retransmission 3
Sender 1 2 3 4 5 6 7 8 1 9 10
Time out 3
Data
Packet
1, 3, 4 are dropped
ACK
Receiver 10
Next is 1
Next is 3
Lack of duplicate ACKs number  Time out  Retransmission

6. Wireless (Including satellite)
Variety of TCP
Trade-off the reliability and efficiency, which is efficiently retransmission?
Which is the best algorithm to define the window control according to network state
What is the approach to solve problem for each typical network
Wired
Wireless (Including satellite)
Ad Hoc
TCP Tahoe
TCP Reno
TCP Newreno
TCP SACK
TCP Vegas
ECN
HighSpeed TCP
FAST TCP
Hamilton-TCP
Scalable TCP
BIC-TCP
CUBIC-TCP
TCP Aflica
MulTCP
Adaptive-TCP
LTCP
Hybla
TCP-Peach
TCP-Westwood
Freeze-TCP
ILC-TCP
JTCP
TCP Veno
TCP-Casablanca
TCP-DCR
TCP-Jersey
TCP-Probing
TCP-Santa Cruz
Delayed Duplicate ACK
I-TCP
M-TCP
METP
Snoop
ELN
EBSN
BA-TCP
Ad hoc TCP
DelAck
ELFN
TCP-ADA
TCP-DOOR
TCP-Feedback
TCP-Bus
Fixed RTO
Split TCP
DDA

7. Experiment 8 4 FTP/TCP 2 3 1 5 25Mbps 5ms 25Mbps 5ms FTP Download4
FTP/TCP
25Mbps
5ms
25Mbps
5ms 2 3
Bandwidth: Bw
Delay: d 1 5
FTP
Download
TCP Agent
TCPSink Agent
Network
Router
Network