User:Dean Turbo/TCP IP

RFCs

 * 1) Assigned Numbers
 * 2) Host Requirements
 * 3) Router Requirements

History
NCP preceded TCP, wasn't duplex: TCP often has odd port numbers.

Common ports

 * 1) echo 7
 * 2) discard 9
 * 3) daytime 13 (human readable)
 * 4) chargen 19
 * 5) time 37 (seconds since January 1 1900 UTC)

The Internet is an internet.

Routers
Router connects networks at IP layer.

Layers

 * 1) Link
 * 2) Network
 * 3) Transport
 * 4) Application


 * Unit of data
 * 1) TCP-IP: TCP segment
 * 2) IP-network interface: IP datagram
 * 3) Network interface-Ethernet: frame

IP
Unreliable, connectionless (expand), "best effort".

TBD

 * 1) Anything sent to host's own IP is sent to loopback, therefore does not usually send to network.
 * 2) Force to send to network? Flash switch LED?
 * 3) Use ARP to get Ethernet address
 * 4) Path MTU needn't be constant? Expand.
 * 5) Routing need not be symmetric.
 * 6) CIDR
 * 7) network byte order
 * 8) Demultiplexing
 * 9) TCP server generally concurrent
 * 10) UDP server generally iterative
 * 11) Ephemeral ports 1024-5000 (still true?)
 * 12) IP &mdash; hop by hop; TCP &mdash; end to end.