What I mean by that is creating a loopback interface and placing it in the particular VLAN as opposed to assigning the VLAN interface an IP address directly. So, for example, let's take a Catalyst 6506. If I'm hosting three VLANs 10-12 that need IP addresses (default routes for three different networks) I would potentially have three loopback interfaces with an IP address (one in each subnet consumed by those VLANs). The alternative is to instead assign the VLAN interfaces the IP addresses and not mess with loopback interfaces.
So lets give an example. Normally I just assign addresses to the VLANs thusly:
int vlan10
description Fiscal
ip address 10.10.10.1
int vlan11
description IT
ip address 10.10.11.1
int vlan12
description Maintenance
ip address 10.10.12.1
I'm asking if it's good, bad, or indifferent to use loopback interfaces instead:
int vlan10
description Fiscal
no ip address
int vlan11
description IT
no ip address
int vlan12
description Maintenance
no ip address
int lo10
switchport
switchport access vlan 10
switchport mode access
ip address 10.10.10.1
int lo11
switchport
switchport access vlan 11
switchport mode access
ip address 10.10.11.1
int lo12
switchport
switchport access vlan 12
switchport mode access
ip address 10.10.12.1
