1. Broader Perspective
A Multiprotocol World

2. Other TCP/IP-IP Standards
Even if you use TCP/IP-OSI, you will not always use HTTP, TCP, and IP at the top layers
There are any other TCP/IP protocols for the application, transport, and internet layers
Application layer protocols for , etc.
Also multiple transport and internet layer protocols; not always TCP and IP

3. Other TCP/IP-IP Standards
Even if you use TCP/IP-OSI, you will not always use PPP and modems at the data link and physical layers
Many other subnet standards
Ethernet and other subnet standards for LANs
Many WAN standards

4. Other TCP/IP-IP Standards
Viewing TCP/IP broadly
Each layer, in other words, can use any of several TCP/IP-OSI protocols
Don’t confuse the standards of webserver access from home using a telephone line and modem (HTTP, TCP, IP, PPP, and serial ports, modems, etc.) with TCP/IP-OSI standards in general

5. You Will Not Always Use TCP/IP-OSI Standards
You almost always will use OSI standards for the data link and the physical layers
However, at higher layers, you may use Non-TCP protocols
IPX/SPX in some Novell NetWare file servers
SNA for mainframes
AppleTalk for Macintoshes
NetBEUI for servers on some small LANs

6. Living in a Multiprotocol World
There are many standards architectures
Each has different layering
Each has multiple standards at each layer
This book will focus on TCP/IP-OSI and some specific TCP/IP-OSI standards only because not all standards can be covered
We live in a multiprotocol world