The TCP/IP Protocol Suite

The TCP/IP protocol suite operates at Layers 3–7 of the OSI seven-layer model.

Network Layer Protocols

Internet Protocol (IP) works at the Network layer, where it takes data chunks from the Transport layer (which become the packet’s payload ), adds addressing, and creates the final IP packet. IP then hands the IP packet to the Data Link layer for encapsulation into a frame.

• Remember the following three protocols
• The full IPv4 packet header has 14 fields but here are a few of them

Transport Layer Protocols

When moving data between systems the TCP/IP protocol suite needs to know if the communication is connection-oriented or connectionless. (TCP or UDP ?)

TCP

Most TCP/IP applications use TCP. TCP gets an application’s data from one machine to another reliably and completely.

• TCP communication rules
• TCP header important fields

UDP

UDP is the “fire and forget” missile of the TCP/IP protocol suite. Two of the most important networking protocols, Domain Name System (DNS) and Dynamic Host Configuration Protocol (DHCP), use UDP.

• UDP header important fields

Application Layer Protocols

TCP/IP applications use TCP/IP protocols to move data back and forth between clients and servers.

IP and Ethernet

TCP/IP supports both LAN and WAN, because every host runs TCP/IP software over Ethernet hardware, creating a situation where every host has two addresses: MAC and IP addresses.

• If computer A wants to send an IP packet to computer B on the LAN, the sending computer must encapsulate the IP packet into an Ethernet frame: