Zusammenfassung der Ressource
TCP/IP
Transport
- Port
Numbers
- For the client/server model to work, the server's computer process must start & open a TCP port, waiting on TCP segments to arrive into that TCP port
- Port numbers for both TCP & UDP range from 0 through 65,535, because they exist in
the headers as 16-bit binary numbers
- To use a port to communicate, an application must ask TCP for
permission to use that port with a process called opening a port
- TCP and UDP
Functions
- The maximum allowed length of data link frame's data field defines the maximum size of an IP packet encapsulated in a data link frame
- TCP provides a guaranteed delivery service to all applications that use TCP, whereas UDP does not
- The size of the UDP data field is potentially limited to some maximum size on
each link, based on that link's IP MTU
- Error
Recovery
- When an error happens, the Recovery happens later
- The TCP error recovery process uses the same SEQ & ACK fields that hosts use to confirm that TCP segments arrive
- When the receiving host gets some of the TCP segments, but
not all, the receiving host can send back an ACK- but with a
value that tells the sender to recover some of the data
- Upper
Layers
- Network layer IP forwarding logic, ignoring the lower layers, follows a hop by hop process between hosts & routers
- The application protocol on the sending host adds an application protocol header, expecting that
the receiving host's application layer protocol will read & react to the contents of that header
- A TCP segment is the part of a message in the network
that begins with the TCP header, through the encapsulated
data, but ignoring the lower-layer headers & trailers