connectionless transport
UDP. do not guarantee reliable data transport
connection-oriented transport
establish logical connection. guarantee reliable data transport, but a little bit slower than UDP.
sequencing
establish order of segments so they dont have to arrive at same time
flow control
sender and reciever coordinate to optimize data transfer speed
three way handshake
integral part of TCP flow control.
1) sender sends SYN message
2) receiving host replies with its own SYN and ACK
3) sending host replies with its own ACK
SYN message
synchronize. request TCP connection. contains starting sequence number. these sequence number establish reliability
ACK
acknowledge reception of original SYN message
PAR
- positive acknowledgement and retransmission
- ensure all segments are recieved in certain amt of time
- sending host will retransmit if acknowledgment not recieved
- recieving has to send acknowledgments for each segment recieved
TCP sliding window
- host can send segments before waiting for acknowledgements
- window defines how many segments can be sent before acknowledgements
acknowledgments most useful for
ensuring data delivery
TCP/IP port
allow different applications to use TCP/IP at same time.
- 0 to 1000 are standard ports
- 1000 to 50k are registered for companies
- 50k to 65k are private ports
routing
figuring out best route to send packets
ICMP
used to send error and status messages. ping command most famous
routing table
stored in router. keeps track of:
1) know networks
2) router interface through which network can be reached
3) metrics associated with each route
routed protocols
used to route data PACKETS
routing protocols
used to send route update packets. most common protocol is RIP
ARP
find MAC address given a IP address
