FTP is a standard protocol for transferring files that suffers from latency and packet loss issues inherent in using TCP. These problems can be solved by using file transfer acceleration techniques that switch from TCP to UDP, eliminating the effects of latency. UDP allows packets to be received out of order and does not stall if packets are dropped, improving throughput. While UDP provides the data channel, error-correcting commands are sent over a separate TCP channel to ensure reliability. This approach can significantly increase transfer speeds compared to standard FTP.

1. Solving the Problems of FTP

2. Overview
• What is FTP?
• How does FTP work?
• Drawbacks of FTP
• Solving the Problems of FTP
• Speed Gains with Acceleration vs. FTP
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3. What is FTP?
• FTP (file transfer protocol) is a standard network protocol
used to transfer files from one host to another on the TCP
protocol
• FTP is one of the oldest protocols on the Internet, first drafted
in the 1970’s (with few changes since!)
• FTP was designed to be completely agnostic – independent
from operating systems, file storage systems, and file types
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4. How Does FTP Work?
• FTP runs on the TCP/IP protocol, using 2 TCP connections
• The first connection used is a control channel used to
exchange instructions and is always open
• The second is a data channel used for file transfer and
directory listings and is opened as needed
2-way control channel (always open)
Client
Server
Data channel (opened as needed)
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5. Drawbacks of FTP
• As FTP is based on the TCP protocol, it inherits the same
drawbacks as TCP including:
– Latency (RTT): TCP/IP requires the receiver to acknowledge each
packet being sent, in sequential order. Each trip is known as round trip
time (RTT) and this communication vastly slows down file transfers,
especially as geographic distance grows
– Packet loss: Network congestion typically causes buffer overflows of
intermediate routers, causing packet loss. Since packets are sent
sequentially, this can cause a hold-up in the cycle, slowing down file
transfers.
• Latency combined with packet loss creates even worse
performance for FTP transfers.
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6. Solving the Problems of FTP with
Acceleration
• File transfer acceleration is possible by optimizing throughput
(removing latency from the equation).
– By switching out TCP for UDP (user datagram protocol) the effects of
latency on a network are eliminated.
– UDP is a “connectionless” protocol that does not depend on
sequenced acknowledgements and retransmissions (unlike TCP).
Without the same acknowledgment requirements as TCP, latency is
effectively eliminated.
– Since UDP allows packets to be received in a different order than they
were sent it does not stall if packets are dropped.
– To ensure reliability with UDP transfers lost packets can be requested
with a command channel: data flows over UDP while error-correcting
commands are periodically exchanged over a TCP/IP stream. Without
the
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7. Speed Gains with Acceleration vs. FTP
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8. About FileCatalyst
FileCatalyst technology is developed by Unlimi-Tech Software Inc., a world
leader in file transfer solutions. Founded in 2000, the company has more than
1000 clients with a user base of over 1 million. FileCatalyst provides softwarebased solutions designed to accelerate and optimize file transfers across
global networks. Being immune to packet loss and latency, FileCatalyst can
send files much faster than methods such as FTP, HTTP or CIFS, while adding
security and reliability.
To learn more visit www.filecatalyst.com
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