8-2 CHAPTER 8: IP UNICAST ROUTING
In Figure 8-1, a Switch 3800 is shown with two VLANs defined: Finance
and Personnel. Ports 1 and 3 are assigned to Finance; ports 2 and 4 are
assigned to Personnel. Finance belongs to the IP network 192.207.35.0;
the router interface for Finance is assigned the IP address
192.206.35.1. Personnel belongs to the IP network 192.207.36.0; its
router interface is assigned IP address 192.207.36.1. Traffic within
each VLAN is switched using the Ethernet MAC addresses. Traffic
between the two VLANs is routed using the IP addresses.
Figure 8-1 Routing between VLANs
Populating the
Routing Table
The Switch 3800 maintains an IP routing table for both network routes
and host routes. The table is populated from the following sources:
■ Dynamically, by way of RIP packets or ICMP redirects exchanged
with other routers
■ Statically, by way of routes entered by the administrator
■ Default routes, configured by the administrator
■ Locally, by way of interface addresses assigned to the
Switch 3800
■ By other static routes, as configured by the administrator
192.207.35.11 192.207.36.12 192.207.35.13 192.207.36.14
1
Finance Personnel
192.207.36.1192.207.35.1
234
192.207.36.0192.207.35.0
SW3800.BK Page 2 Tuesday, May 5, 1998 5:20 PM