846 Configuring Routing Interfaces
In Figure 30-1 the PowerConnect switch is configured as an L3 device and 
performs the routing functions for hosts connected to the L2 switches. For 
Host A to communicate with Host B, no routing is necessary. These hosts are 
in the same VLAN. However, for Host A in VLAN 10 to communicate with 
Host C in VLAN 20, the PowerConnect switch must perform inter-VLAN 
routing.
Figure 30-1. Inter-VLAN Routing
Loopback Interfaces
When packets are sent to the loopback IP address, the network should be able 
to deliver the packets as long as any physical interface on the switch is up. 
There are many cases where you need to send traffic to a switch, such as in 
switch management. The loopback interface IP address is a good choice for 
communicating with the switch in these cases because the loopback interface 
cannot go down when the switch is powered on and operational. 
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PowerConnect Switch
L2 Switch
L2 Switch
Host A
Host B
Host C
VLAN 10
VLAN 20