service port number
transport layer
The routing process occurs in the 3rd OSI layer (network layer) routing protocols use network address (IP address in TCP/IP) to chose the correct path to the destination. ps: You can also have routing protocols on other layers sometimes (application layer in p2p routing) but this is something completely different.
+network layer logical communication between hosts +transport layer: logical communication between processes ex: we have 2 house and one house have 12 room. kids in the houses send letter together. network layer: only send letter between the houses transport layer: it make sure that the letter be sent to right the room in the house.
Network Layer
Typically TCP (the Transmission Control Protocol) is responsible for adding reliable delivery mechanisms to information flows. It operates at the Transport Layer. Some applications use the session layer in addition to or in place of transport layer mechanisms however.
The data link layer header contains the destination and source of information of the original frame and device sending information. You will also find that it contains the information of the device to receive it.
Network Layer
the Layer 2 source and destination address
transport layer
The destination host address
The data link layer header contains the source's physical address. It refers the address that is found in the Network Interface Card.
Transport layer is responsible for reliable delivery of information, error correction and so on.
An atmospheric layer that contains layer is stratosphere. It contains ozone layer.
Trailer is added at only data link layer because data link layer provides error and flow control.Header Contains address of device where frames will be send
Layer 3 of the OSI model. An ICMP header follows the IP header of the IP packet.
The routing process occurs in the 3rd OSI layer (network layer) routing protocols use network address (IP address in TCP/IP) to chose the correct path to the destination. ps: You can also have routing protocols on other layers sometimes (application layer in p2p routing) but this is something completely different.
HEADERS: It is a part of an information structure that precedes and identifies the information that follows,such as block of bytes in communication.TRAILERS:It is an information typically occupying several bytes ,at the tail end of a block of transmitted data which may contain a checksum or other error-checking data useful for confirming the accuracy and status of transmission.