fourth layer
Application Layer
Megaco/H.248 is an Application Layer protocol and works on TCP/UDP.
TCP and UDP are transport layer protocols; the OSI layer is layer 4 (transport)
TCP operates at transport layer
smtp, http, anything on that specific OSI layer.
UDP or User Datagram Protocol works on the Transport Layer (layer 4) in the OSI model.
There is a good descrition of the network layer and TCP in the related link. NO. In general TCP and UDP are transport protocols that operates in Layer 4 Transport Layer
HTTP works over a TCP connection.HTTP works over a TCP connection.HTTP works over a TCP connection.HTTP works over a TCP connection.
A firewall generally works at layer 3 and 4 of the OSI model. Layer 3 is the Network Layer where IP works and Layer 4 is the Transport Layer, where TCP and UDP function. Many firewalls today have advanced up the OSI layers and can even understand Layer 7 - the Application Layer.
TELNET operates at Application Layer in TCP/IP Model. It's an Application to establish a connection to TCP Port Number 23, where a Telnet server application (telnetd) is listening.
The tcp layer
The Transport layer