you can see it, HERE
- Rout able: it can pass through routers.
- Connect dissimilar systems: Win, Mac, Unix, etc...
- Method of access to the inventor.
App Layer: using an app, it gains access to the network.
Telnet, FTP, TFTP , NFS, SMTP, LPD, DNS, DHCP.
Transportation: provides communication sessions between the two computers. TCP, UDP
Internet Layer: routers the data from it's source to it's source to its destination. ARP, RARP, IP, ICMP, IGMP.
Network Layer: it sends & receive data on the wire. Ethernet, Token Ring, Frame, Relay, ATM
(Well-Know Port Numbers:
FTP: 20 & 21, SMTP: 25, DNS: 53, Telnet:23, HTTP: 80, HTTPS: 443)
** IMPORTANT FIELDS
- Source port: sending App port number
- Destination port: receiving App number
- Sequence number: maintains reliability & sequencing
- Acknowledgement number: used to acknowledge received segments formation .
- Windows: the number of segments that are allowed to be sent before waiting for an acknowledgement from the destination.
- Checksum: CRC of the header & data.
- Data: user App information.