Enterasys Networks 6H2xx - Manual (Page 402)

Example 2, VLANs Across Multiple Switches
13-30 VLAN Operation and Network Applications
Figure 13-14 Transmitting to Switch 4
3. When Switch 2 receives the tagged frame on its Port 2, it checks the frame’s VLAN Tag Header
and determines that the frame is classified as belonging to the Red VLAN, and that the frame is
a broadcast frame. Switch 2 forwards the frame to all ports in the Red VLAN Forwarding List
excluding Port 2, which received the frame. In this example, the only eligible port is Port 3,
which connects to Bridge 4. Switch 2 checks its Forwarding List, which specifies that the VLAN
frame type for that port is untagged. Switch 2 then updates its Source Address Table in FDB ID
2 for MAC address “Y” if necessary. The untagged frame is then transmitted out Port 3 to
Bridge 4. Bridge 4 forwards the frame out all its ports because it is a broadcast frame, and the
server receives it as shown in
Figure 13-15 .
Floor 2
22631_15
Floor 3
Floor 4
Bridge 1 Bridge 2
Bridge 3
Bridge 4
Redco
Redco
Blue Industries
Blue Industries
Red VLAN Red VLAN
Red VLAN Red VLAN
Blue VLAN Blue VLAN
Blue VLAN Blue VLAN
User A
File Server
4
2
1
2
3
4
1
2
3