Which File Transfer Protocol Uses UDP?

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TLDR: The article explains that while most file transfer protocols like FTP and HTTP use TCP, some use UDP for data transport because it can be faster but less reliable. It highlights that UDP itself has limitations such as lack of built-in reliability and congestion control. IBM Aspera’s FASP technology is presented as a solution that leverages UDP’s speed while adding reliability, congestion adaptation, and high performance for large file transfers.

UDP, or User Datagram Protocol, is used to transfer large files across the internet. While the Transmission Control Protocol (TCP) is the more known and used protocol, it falls short when it comes to transferring large files at fast speeds in comparison to UDP. UDP is commonly used for transferring files for:

• Audio Communication
• Video Communication
• Peer-to-Peer File Sharing

Both of these protocols break down large data sets into individual packets that are sent across the internet. They hop from one node to the next until they end up at their destination. Once the packets have arrived, the data set is reconstructed and the file is back to its original state.

Some file transfer protocols like HTTP, HTTPS, and FTP use TCP, which does not perform well in difficult network conditions. Some protocols that use UDP include DNS, VoIP, and DHCP. 

Disadvantages of UDP

While UDP is more lightweight than TCP and requires no dedicated connection, there are still some disadvantages of UDP. Some of these drawbacks include:

1. Unreliable: Because there is no concept of retransmission, acknowledgment, or time, UDP can be unreliable. When data is sent, it cannot be guaranteed that it will be delivered to its destination host. Sometimes it can be lost on its way or delivered twice.
2. Incorrect Order: Apart from data being undelivered, it can also be out of order. The sequence in which packets are sent cannot be guaranteed to be in the same order when they reach the host.
3. No Congestion Control: Congestion control methods are not present in UDP. This means that any congestion between the sender and receiver are not accounted for and the protocol cannot adapt.

IBM Aspera for File Transfers

IBM Aspera fills the gaps left by TCP and UDP in providing reliable, high-performance file transport. It eliminates the fundamental bottlenecks of TCP- or UDP-based file transfer technologies like FTP and others.

Using standard UDP in the transport layer, it achieves decoupled congestion and reliability control in the application layer. Through that, Aspera retransmits precisely the real packet loss on the channel. Data that is lost in transmission is retransmitted at a rate that matches the available bandwidth inside the end-to-end path with zero duplicate retransmissions.

Using FASP adaptive rate control, Aspera uses measured queuing delay as the primary indication of network congestion with the aim of maintaining a small, stable amount of queuing in the network. This allows FASP to work at high performance while responding to congestion along the transfer path.

Does FTP Use TCP or UDP?

FTP uses TCP, not UDP. It relies on TCP for both the control connection and the data connection. This design ensures reliable delivery, ordered packets, and built-in error correction. The downside is performance. TCP slows down significantly on high-latency or high-packet-loss networks. This makes traditional FTP inefficient for large file transfers over long distances, especially in global or cloud-based environments.

Which Protocol Uses UDP?

Most traditional file transfer protocols do not use UDP. One notable exception is IBM Aspera, which uses a proprietary protocol called FASP that runs on UDP. UDP allows Aspera to avoid TCP congestion limitations while adding its own reliability, encryption, and congestion control at the application layer. This makes UDP-based transfers ideal for moving very large files quickly and securely across long distances where TCP-based protocols struggle.

Learn More About Aspera with PacGenesis

PacGenesis is an IBM Gold Business Partner, which means we’ve earned IBM’s trust to implement their Aspera software with businesses looking for a reliable and fast file transfer solution. With over 10 years of experience, our team is ready to help you figure out the best service and software that can help your business. To better identify your high-speed transfer needs and set up an evaluation, contact us today.

To learn more about PacGenesis, follow @PacGenesis on Facebook, Twitter, and LinkedIn or contact us at pacgenesis.com.

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