Chapter 5: Key Protocols and Interfaces
Figure 14 on page 69 shows an example network that uses VLANs. In this example network, the physical LAN consists of a switch, two servers, and five clients. The LAN is logically organized into three different VLANs, each representing a different IP subnet. The features of this network are described in Table 8.
| Table 8. Example VLAN Network Topology | |
|
|
|
Component |
| Description |
|
|
|
VLAN #1 |
| An IP subnet consisting of the Main Server, PC #3, |
|
| and PC #5. This subnet represents an engineering |
|
| group. |
|
|
|
VLAN #2 |
| Includes the Main Server, PCs #1 and #2 via shared |
|
| media segment, and PC #5. This VLAN is a software |
|
| development group. |
|
|
|
VLAN #3 |
| Includes the Main Server, the Accounting Server and |
|
| PC #4. This VLAN is an accounting group. |
|
|
|
Main Server |
| A |
|
| of the VLANs and IP subnets. The Main Server has an |
|
| |
|
| accessed via the single physical adapter interface. |
|
| The server is attached to one of the switch ports, |
|
| which is configured for VLANs #1, #2, and #3. Both |
|
| the adapter and the connected switch port have |
|
| tagging turned on. Because of the tagging VLAN |
|
| capabilities of both devices, the server is able to |
|
| communicate on all three IP subnets in this network, |
|
| but continues to maintain broadcast separation |
|
| between all of them. |
|
|
|
Accounting |
| Available to VLAN #3 only. The Accounting Server is |
Server |
| isolated from all traffic on VLANs #1 and #2. The |
|
| switch port connected to the server has tagging |
|
| turned off. |
|
|
|
PCs #1 and |
| Attached to a shared media hub that is then |
#2 |
| connected to the switch. PCs #1 and #2 belong to |
|
| VLAN #2 only, and are logically in the same IP subnet |
|
| as the Main Server and PC #5. The switch port |
|
| connected to this segment has tagging turned off. |
|
|
|
PC #3 |
| A member of VLAN #1, PC #3 can communicate only |
|
| with the Main Server and PC #5. Tagging is not |
|
| enabled on PC #3’s switch port. |
|
|
|
PC #4 |
| A member of VLAN #3, PC #4 can only communicate |
|
| with the servers. Tagging is not enabled on PC #4’s |
|
| switch port. |
|
|
|
70
