Difference between tcp and udp

TCP is a connection-oriented protocol, whereas UDP is a connectionless protocol. A key difference between TCP and UDP is speed, as TCP is comparatively slower than UDP. Overall, UDP is a much faster, simpler, and efficient protocol, however, retransmission of lost data packets is only possible with TCP.

TCP guarantees (in-order) packet delivery. UDP doesn’t. TCP – used for traffic that you need all the data for. i.e HTML, pictures, etc. UDP – used for traffic that doesn’t suffer much if a packet is dropped, i.e. video & voice streaming, some data channels of online games, etc.

TCP (Transmission Control Protocol)

UDP (User Datagram Protocol) TCP is a connection-oriented communication protocol. UDP is a connectionless communication protocol. TCP data units are known as packets. UDP data units are commonly referred to as datagrams (although they’re sometimes called packets as well).

UDP is commonly used for applications that are “lossy” (can handle some packet loss), such as streaming audio and video. It is also used for query-response applications, such as DNS queries.

UDP (User Datagram Protocol) is a communications protocol that is primarily used for establishing low-latency and loss-tolerating connections between applications on the internet. It speeds up transmissions by enabling the transfer of data before an agreement is provided by the receiving party.

Netflix, Hulu, Youtube, etc. video streaming all use TCP and simply buffer a few seconds of content, instead of using UDP since the delay is not crucial and TCP transfers can be easily accomplished over HTTP and web browsers without the need for additional plugins and software.

UDP reduces overhead because it does not add flow control, error control, or sequence delivery unlike connection-oriented services. UDP is used for the transmission of data in which delivery of the data is more important than accuracy. Therefore, UDP is needed.

Examples include Voice over IP (VoIP), online games, and media streaming. Speed – UDP’s speed makes it useful for query-response protocols such as DNS, in which data packets are small and transactional.

Even though UDP is a stateless protocol, the firewall treats it as if it were stateful traffic, and it documents it in its stateful connection table. Since the ASA has no way to track the state of the packet exchanges in the UDP connection, it has no way to determine when the UDP connection is over.

HTTP and connections

Among the two most common transport protocols on the Internet, TCP is reliable and UDP isn’t. HTTP therefore relies on the TCP standard, which is connection-based. For example, Google is experimenting with QUIC which builds on UDP to provide a more reliable and efficient transport protocol.

HTTP/3 doubles down on that, offering very similar features but replacing TCP with UDP. This time more fundamental changes to networking infrastructure may be required to take advantage of the better performance over poor connections and mobile networks, but for most developers, the change will be transparent.

HTTPS over UDP is secure.

There are two that you can choose from – Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). In essence, both of them are doing the same thing, allowing you to transfer data. However, they do it in different ways, which means that it matters which one you use.

Because most protocols use TCP, many enterprise firewalls are configured to simply block UDP. This allows the firewall to protect the network and protect hosts from several attack vectors (replay attacks, host IP address probing, DDOS attack etc.).

UDP is stateless and connectionless in that there is no handshake to set up a session, and no connection between the sender and receiver; the packets may take different routes to get to a single destination.

DTLS (Datagram transport Layer Security) is a protocol that provides privacy for UDP communications.

Wikipedia: TLS belongs to the Application layer in terms of the TCP/IP model.

TLS was designed to operate on top of a reliable transport protocol such as TCP. However, it has also been adapted to run over datagram protocols such as UDP.

TLS is a cryptographic protocol that provides end-to-end security of data sent between applications over the Internet. It is mostly familiar to users through its use in secure web browsing, and in particular the padlock icon that appears in web browsers when a secure session is established.

The existence of TLS 1.0 and 1.1 on the internet acts as a security risk. Clients using these versions are suffering from their shortcomings, while the rest of the internet is vulnerable to various attacks exploiting known vulnerabilities, for almost no practical benefit.