3Com SuperStack II 3300, User Manual

Page: 23 / 172

Network Configuration Examples 23
Addition of Multiple VLANs per Switch
In Figure 6, the Switches are connected by 802.1Q tagged links . 802.1Q
tagged links are links that use the tagging system defined in the IEEE
802.1Q standard to carry traffic for multiple VLANs. Using the 802.1Q
tagged links, the Layer 3 Module can tell Switches A, B and C which
VLAN the packets are destined for. All Switches at the end of the links
receive traffic for all VLANs.
Figure 6 Network Using Multiple VLANs
The Switches could also be connected in a stack using a SuperStack II
Switch Matrix Module. For further information, see the user guide for the
SuperStack II Switch Matrix Module.
Traffic on each VLAN is switched at Layer 2 via Switch D, and routed at
Layer 3 to other VLANs via the Layer 3 Module. For example, traffic from
VLAN 1 on Switch A is switched to VLAN 1 on Switch B via Switch D.
Traffic from VLAN 1 on Switch C to VLAN 2 on Switch C is routed at
Layer 3 through the Layer 3 Module on Switch D.
Packets routed
between VLANs
Switch A
VLAN 3
Subnet mask: 255.255.255.0 192.168.170.0
Switch B
Switch C
VLAN 1
Subnet mask: 255.255.255.0
192.168.168.0
VLAN 2
Subnet mask: 255.255.255.0
192.168.169.0
802.1Q
tagged link
Server
Workstation
Key
Cable
Layer 3 Module
Switch D
VLAN 1
Subnet mask: 255.255.255.0
192.168.168.0
VLAN 2
Subnet mask: 255.255.255.0
192.168.169.0
VLAN 1
Subnet mask: 255.255.255.0
192.168.168.0
VLAN 2
Subnet mask: 255.255.255.0
192.168.169.0