Cisco Campus Design Best Practice. The current recommended practice is to use ieee 802.1q trunks. As a result, it is a good practice to avoid allowing the core and distribution switches to route traffic via access layer or server vlans, such as 101 and 102 or 401 and 402.
With security in place, we can take some initiative in designing the campus to decrease the size of broadcast domains by limiting where vlans traverse. The threshold value of 1 percent is given as an example. Cisco campus designs also use layers to simplify the architectures.
