WAN/VLAN Example Deployment

In the Overview of this section, an example deployment of PXE is given for a WAN/VLAN environment. Then, the following sections provide the specific steps required to configure network equipment so that they will correctly forward PXE network traffic:

• Configuring Cisco Equipment
• Configuring Nortel Network Equipment
• Configuring Bay Network Equipment

Overview

In this example, three VLAN are configured on a Bay Networks Accel 1200 switch running firmware version 2.0.1. One VLAN hosts the Proxy DHCP service, the second VLAN hosts the DHCP service, and the third VLAN hosts the PXE client. The PXE client's DHCP broadcast is forwarded by the switch to both the Proxy DHCP service and the DHCP service. The response from both servers is then routed correctly back to the PXE client, and the PXE client starts the PXE session correctly.

The three VLANs are all 24-bit networks, that is their subnet mask is 255.255.255.0

The first VLAN gateway is 10.0.0.1. This VLAN hosts the PXE client that is allocated an IP in the range of 10.0.0.2 to 10.0.0.128. This VLAN is named VLAN1.

The second VLAN gateway is 10.1.1.1. This VLAN hosts the DHCP server with IP 10.1.1.2. This VLAN is named VLAN2.

The third VLAN gateway is 196.10.229.1. This VLAN hosts the server running the Proxy DHCP server and the Transaction server. The server's IP is 196.10.229.2. This VLAN is named VLAN3.

Routing is enabled between all the VLANs. Each VLAN is (and must be) in its own spanning tree group.

Configuring Cisco Equipment

1. Go to Global Configuration mode.

2. Type ip forward-protocol udp 67 and press Enter.

3. Type ip forward-protocol udp 68 and press Enter.

4. Go to the LAN interface that serves the PXE workstation.

5. Type ip helper-address 10.1.1.2 and press Enter.

6. Type ip helper-address 196.10.229.2 and press Enter.

7. Save the configuration.

Configuring Nortel Network Equipment

1. Connect to the router with Site Manager.

2. Ensure that IP is routable.

3. Enable Bootp on the PXE workstation subnet/VLAN.

4. Select the interface that the PXE workstations are connected to.

5. Edit the circuit.

6. Select Protocols.

7. Select Add/Delete.

8. Ensure there is a check in the Bootp check box.

9. Press OK.

10. Select Protocols > IP > Bootp > Relay Agent Interface Table.

    The interface where Bootp was enabled will visible in the list.

11. Click Preferred Server.

12. Change the Pass Through Mode value to Bootp and DHCP.

Set up the relay agents:

1. Click Add.

2. In the Relay Agent IP Address box, type the local LAN IP address.

3. In the Target Server IP Address box, type the DHCP server IP address.

4. Click OK.

5. Change the Pass Through Mode value to Bootp and DHCP.

6. Perform steps 1-5 again and enter the Proxy DHCP server IP address at Step 3.

7. Apply the configuration.

Configuring Bay Network Equipment

Perform the following steps on the switch:

1. Enable DHCP for the client VLAN using the following command lines:

   # config vlan1 ip

   # dhcp enable

2. Configure ip helpers to forward DHCP requests from the workstation subnet to the Proxy DHCP service, using the following command lines:

   # config ip dhcp-relay

   # create 10.0.0.1 10.1.1.2 mode dhcp state enable

   # create 10.0.0.1 196.10.229.2 mode dhcp state enable

   The create command has the form create agent server mode dhcp state enable, where agent is the IP address of the gateway that serves the PXE workstation, and server is the IP address of the server that the DHCP frame should be forwarded to.

3. Save the configuration.