D-Link DES-3326 User Manual - Ip Level
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
86
Switch Management and Operating Concepts
number in the window field. In practice, a single packet can
acknowledge the receipt of data and give permission for more data
to be sent.
IP Level
TCP sends its packets to IP with the source and destination IP
addresses. IP is only concerned with these IP addresses. It is not
concerned with the contents of the packet or the TCP header.
IP finds a route for the packet to get to the other end of the TCP
connection. IP adds its own header to the packet to accomplish
this.
The IP header contains the source and destination addresses, the
protocol number, and another checksum.
The protocol number tells the receiving IP which protocol to give
the packet to. Although most IP traffic uses TCP, other protocols
can be used (such as UDP).
The checksum is used by the receiving IP in the same way as the
TCP checksum.