Novell NETWARE 6-DOCUMENTATION Manual page 1421

Figure 1 OSI Reference Model
OSI Reference Model
Layer Function
1
Application
2
Presentation
3 Session
4
Transport
5
Network
6
Data Link
7
Physical
Table 1
12
NetWare TCP/IP Administration Guide
illustrates the seven layers of the OSI reference model, as defined by ISO, and
the roughly corresponding layers of the TCP/IP protocol suite.
TELNET FTP
TCP
IP
Ethernet
The layering system allows the developers to concentrate their efforts on the
functions in a given layer. It is not necessary for designers to create all the
mechanisms to send information across the network. They have to know only
what services the software needs to provide to the layer above it, what services
the layers below it can provide to the software, and which protocols in the
suite provide those services.
Table 1 lists some of the more common protocols in the TCP/IP suite and the
services they provide.
TCP/IP Protocols
Protocol
Internet Protocol (IP)
Internet Control Message
Protocol (ICMP)
TCP/IP Protocol Suite
Protocol
SMTP
ICMP RIP
Token
Ring
Service
Provides packet delivery services (routing)
between nodes.
Provides transmission of error and control
messages between hosts and routers.
DNS SNMP
UDP
OSPF EGP
ARP RARP
Other
Media