the tcp and udp protocols both exist at what layer of the osi model
OSI model Although not developed under the OSI Reference Model and not strictly conforming to the OSI definition of the transport layer, the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) of the Internet Protocol Suite are commonly categorized as layer-4 protocols within OSI.
Address Resolution Protocol The Address Resolution Protocol is a request and response protocol whose messages are encapsulated by a link layer protocol. It is communicated within the boundaries of a single network, never routed across internetwork nodes. This property places ARP into the link layer of the Internet Protocol Suite.[2] Although ARP was not developed in the OSI model, it is often described here as residing in layer 3, being encapsulated by Layer 2 protocols.[citation needed]