Can TCP be implemented via UDP?

networking tcp udp
user34537 picture user34537 · May 21, 2012 · Viewed 25.2k times · Source

I had a strange idea. I heard of software which from my understanding uses UDP to transfer files decreasing the overhead found in TCP packets.

If my app requires TCP and my LAN has software set up to communicate with another datacenter on the other side of the coast with software setup on their end. Would it be possible to send the actual data via UDP but than simulating TCP on both ends?

Does anyone have any ideas or information about such projects?

Answer

mpontillo picture mpontillo · May 22, 2012

If you're asking if you can use UDP as a Layer 2, then the answer is yes, sort of. There are various protocols that allow you to create a tunnel to another network using a UDP transport, such as L2TP and even IPsec (with NAT traversal). You could also do it at the application layer.

If you're asking if TCP can be implemented in UDP, the answer is no. First, TCP packets and UDP packets have an incompatible format. Second, TCP and UDP have different protocol numbers (seen in the IP header) which means that TCP traffic destined for a UDP port would not be passed to the correct upper-layer protocol.

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