2. TCP/IP suite
• TCP/IP is part of a larger protocol suite.
• IP suit most used and most proven suite in the
world
• Contains specifications for email, ftp, and
terminal emulation.
• TCP/IP transport and network layer of OSI
model but is based on it’s own 5 layer
protocol (simplified OSI)
3. OSI to IP suite relation
Copyright, Cisco system
4. Transmission Control
• Layer 4 on TCP/IP model
– Directly under application layer.
– Combination of Presentation, session, and
transmission layers.
• Data unstructured stream of bytes
• Main purpose is error checking and flow
control
5. Transmission Control
• TCP segmented into Header and Data section
• Uses Ports to identify Source and destination
(16 bit number)
• Data belonging to specific TCP connections are
identified by sockets
– Combination of source and destination host
address and port
– Allows servers to provide multiple services to
multiple clients.
6. Flow Control and Error checking
• Sending Node
– Sequence of numbers and Acknowledgement
messages
– Delivery information for destination
• Retransmission of data if data loss occurs
• Drops duplicate data
• Slows transmission if destination computer is
behind
7. Internet Protocol
• Heart of the TCP/IP suite
• Primary Layer 3 protocol
• Packet-switching (apposed to circuit
switching)
• Error reporting
• Fragmentation and reassembly of Datagrams
– Data larger than MTU (max transmission unit) is
fragmented by IP.
8. Internet Protocol
• Data encapsulation (fragmentation) allows
packets to travel over any type of network with
no concern for Higher layer operations.
– Email and ftp can travel over the same or separate
networks.
• IP does not account for data error
– Best effort delivery
– No guarantees that data will arrive at destination
– Up to TCP to ensure data transmission
• Does ensure reassembled fragments are in order.
• Does error check it’s IP header.
9. IP Address
• Globally unique
• 3 classes, A, B, and C
• Divided into 3 parts, Network, subnet, host
address
• Allow IP networks to communicate with each
other across the world
• Networks can be subdivided further with a
subnet mask
11. IP address Classes
• Class A for Large networks
– 8 bits for network section
• Class B 16 bits for network
• Class C 24 bits for network leaving 8 bits for
Hosts
• Leftmost bits indicate Class
12. Why?
• Internet
– TCP/IP is why the internet works
– Interconnecting networks
– Allows for any network to communicate with
another
• TCP/IP allows data to move through separate
networks until it reaches it’s destination
through routing.
