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

Network class

Class	bits	Network ID bits	Host ID bits	IP range
A	0	7	24	TBD
B	10	14	16	TBD
C	110	21	8	TBD
D	1110	0	28 (multicast)	TBD
E	reserved	reserved	reserved	TBD

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 — hop by hop; TCP — end to end.