DNS doesn't need any of these mechanisms for simple queries since the typical amount of sent data is tiny. TCP is optimized for long data transfers and has a bunch of complex mechanisms such as flow control and congestion control for optimizing the rate of data flow. Simplicity - UDP is a lot simpler than TCP. Lower data overhead - a UDP header is tiny compared to the header TCP sends for every segment. Otherwise, they might end up reaching different servers which won't know what to do with them. Since TCP involves multiple packets sent back and forth, reliable anycast is harder to achieve since you need to make sure that the packets always reach the same exact server. When you send a query to 1.1.1.1, one of these servers (probably one of the closest ones geographically) gets it. I haven't seen anybody use that API just because it's a. You can, in theory, get UDP-like characteristics out of a different web API - with a WebRTC datachannel configured to be unreliable and unordered. Gaffer on Games has an excellent article on the topic. In anycast, several servers (possibly around the world) share a single IP address - e.g. Others have hit the TCP/UDP thing pretty big - TL DR TCP is 'chatty' while UDP isn't. UDP makes it easy to deploy anycast DNS servers. TCP requires both the client and server to have a separate socket for each and every connection. UDP would only require one RTT, so 20ms.ĭue to TCP's connection-oriented nature, more resource are needed per-connection to store and manage TCP's state. So if it takes 20ms for a message to travel from your computer to the server and back (a time known as RTT - Round Trip Time), then a TCP query would require 3xRTT (60ms) to be fully processed - 20ms for opening the connection, 20 more ms for the query, and another 20ms to tear it down. TCP requires a connection to be established before each request, then subsequently torn down. If youre unaware of your IP address, go to Command Prompt and type ipconfig. TCP is a connection-oriented protocol, which means, once a connection is established, data can be sent bidirectional. There are several reasons why TCP DNS queries are slower: 2.1, UDP or TCP: TCP is more reliable and UDP is faster. Soulseek settings: port 50315 xFinity modem port forwarding settings. Difference between TCP and UDP - Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) are the most widely used Internet protocols. The biggest advantage to using UDP is the performance boost. In practice, most DNS servers support both UDP and TCP, though TCP is rarely used for simple DNS queries and is reserved mainly for operations like zone transfers. First of all, it is important to note that TCP can also be used for DNS.
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