Ip Routing And The Osi Reference Model - 3Com CoreBuilder 2500 User Manual

4
IP Routing and the
OSI Reference
Model
R
OUTING WITH
This chapter reviews IP routing technology in these sections:

IP Routing and the OSI Reference Model

Elements of IP Routing
IP Routing Transmission Errors
Routing with Classical IP over ATM
IP Routing References
An IP router, unlike a bridge, operates at the network layer of the Open
Systems Interconnection (OSI) Reference Model. An IP router routes
packets by examining the network layer address (IP address). Bridges use
data link layer MAC addresses to perform forwarding. See Figure 4-1.
OSI Reference Model
Application layer
Presentation layer
Session layer
Transport layer
IP
Network layer
ARP
MAC
Data link layer
Physical layer
Figure 4-1 OSI Reference Model and IP Routing
IP T
ECHNOLOGY
RIP OSPF
ICMP