Router Interfaces - 3Com CoreBuilder 2500 User Manual

4-4 C 4: R
HAPTER OUTING WITH

Router Interfaces

IP T
ECHNOLOGY
An example of an IP address that includes network, subnetwork, and host
parts is 158.101.230.52 with a subnet mask of 255.255.255.0. This
address is divided as follows:
158.101 is the network part
230 is the subnetwork part
52 is the host part
As shown in this example, the 32 bits of an IP address and subnet mask
are usually written using an integer shorthand. This notation translates
four consecutive 8-bit groups into four integers ranging from 0 through
255. The subnet mask in the example is written as 255.255.255.0.
A router interface connects the router to a subnetwork. In traditional
routing models, the interface is the same as the port because only one
interface can exist per port. In the IP routing model for the
™
CoreBuilder 2500 system, more than one port can connect to the same
subnetwork.
Each router interface has an IP address and a subnet mask. This router
interface address defines both the number of the network to which the
router interface is attached and its host number on that network. A
router interface IP address serves two functions:
For sending IP packets to or from the router.
For defining the network and subnetwork numbers of the segment
connected to that interface. See Figure 4-4.
Network 1
158.101.1.2
Interface 1
158.101.1.1
Figure 4-4 Router Interfaces in the CoreBuilder 2500 System
Network 2
Interface 2
158.101.2.2
1 2
Router
3
158.101.3.2
Interface 3
Network 3
158.101.2.1
158.101.3.1