Transport Layer Tasks:-tracks conversations-manages data for many applications-segments data-multiplexes applications

numbering and

sequencing

-tracks conversations

-manages data for many applications

-segmentaion-multiplexing

Voice:Daten:

vollständig

schnell, < 80ms delay

dafür ist TCP geeignetdafür ist UDP geeignet

64-20 bis 1500-20 Byte

64-20 bis 1500-20 Byte

TCP Ports

UDP Ports

Internet Assigned Numbers Authority (IANA)

Port Adressing:-identifies the communicating applications

-enables a receiving host to forward the data to the appropriate application

-identifies multiple conversations between the hosts

Anmerkung: Microosoft Windows verwendet für Webbrowser Ports im Bereich 1024 bis etwa 5000.(Diese „RPC dynamic port allocation“ Einstellungen können geändert werden.)

TCP Connection Termination:

netstat –n zeigt als State:TIME_WAIT

TCP is connection-oriented !

TCP Connection Establishment:

Data Transfer:

3-Way Handshake:initializes the sequence numbers for the session.

The 3-Way Handshake initializes the sequence numbers for the session.

packets will be delivered and reassembled at the destination

Source Destination

Flow Control with Window Size = 10

Only the data in the segments that complete the stream are acknowledged.

Timeout:A host transmits segments and starts a timer. If the acknowledgment is not received before the timer expires, the segments are retransmitted.

timeout and resend the data that needs to be acknowledged

Flow Control:to prevent the receiver from being overwhelmed by incoming data, provided by window size

connectionless

low overhead: