1. Total Standards Picture
Client PC and Server Must be Compatible at All Six Layers
Application
Application
Transport
Transport
Internet
Internet
LAN Subnet
(NIC)
LAN Subnet
(NIC)

2. Application (service)
Upper Layers
Application Layer
Standard depends on the application
File service
Print services
Electronic mail
Etc.
Application (service)

3. Upper Layers Transport and Internet Layers
All new servers use TCP/IP standards
Transport layer: TCP
Internet layer: IP
Transport (TCP)
Internet (IP)

4. Upper Layers Novell NetWare Now uses TCP/IP
Before, used NetWare’s proprietary IPX/SPX
Many old NetWare servers still use IPX/SPX
Application
Other
NCP
Transport
SPX
Internet
IPX
IPX

5. Upper Layers Novell NetWare IPX at the internet layer
NCP at transport & application
File service, print service, etc.
SPX sometimes at transport
Application
Other
NCP
Transport
SPX
Internet
IPX
IPX

6. Upper Layers
All Servers on a LAN Use the Same Subnet Layer Standards, which are implemented by NICs
Servers can differ in upper-layer standards
App
App
App
TCP
SPX
NetBEUI IP
IPX
802.2
802.2
802.2
802.3 MAC
802.3 MAC
802.3 MAC
100Base-TX
100Base-TX
100Base-TX

7. Upper Layers Client Software is Flexible
Speaks TCP/IP to Windows NT Server, UNIX, new Novell NetWare Servers
Speaks IPX/SPX to older NetWare Servers
Simultaneously!
TCP/IP
IPX/SPX