Interconnect Switch User Guide

Spanning Tree Protocol
Compaq ProLiant BL p-Class GbE Interconnect Switch User Guide D-13
COMPAQ CONFIDENTIAL Codename: Vanilla Part Number: 263680-001 Last Saved On: 4/23/02 10:15 AM
Figure D-9: Common network design example 1
The preceding graphic is an example of a common network design. The switches C and D
have redundant links to the backbone switches A and B using trunks. Trunks, by default,
carry all the VLAN traffic from VLAN 1 and VLAN 2. So switch C is not only receiving
traffic for VLAN 1, but it is also receiving unnecessary broadcast and multicast traffic for
VLAN 2. It is also blocking one port for VLAN 2. Thus, there are three redundant paths
between switches A and B and two blocked ports per VLAN. This increases the chance of a
data loop.