"IP routed subnet" on cisco C921 router

[MBestt]

Hello,

We currently have a setup with a Draytek router. This router has 'IP routed subnet' configured on it. From my understanding this is a Draytek concept. The construction is as following:

First we have the uplink to our ISP. This is connected to the WAN-interface of the Draytek. The Draytek is configured with PPPoE on the WAN-interface and when authenticated it gets the .169. (in total we have x.x.x.169/29 public IP's from the ISP).

The LAN-1 interface on the Draytek is connected to a Cisco 8-p switch that is then connected to 2 Palo Alto firewalls (configured in HA). Those Palo Alto firewalls have the .170 public IP-addres. When I plug in my PC on the second LAN-port (Draytek), I get the .171 IP from the ISP. From what I can see, this is done by a DHCP-pool on the Draytek. When I do IPCONFIG, I see the public IP-adres and that the .169 (Draytek) is the gateway.

Now my question is, how do I configure this construction on the Cisco C921 router? What are the steps I need to perform?

1. Create Dialer interface with PPPoE settings

2. ....???


Kind regards,

Jeffrey

[MHM Cisco World]

Troubleshoot Bridge Virtual Interface & Bridge Domain Interface - Cisco

MHM

[Richard Burts]

Jeffrey

Certainly setting up the outside interface of the C921 for PPPOE is the important first step. 

From your description I believe that there is a DHCP pool and I believe that it is at the ISP and not on the Draytek. 

Your description indicates that the interface connecting to ISP, interface connecting to 8 port switch, and other interface on Draytek are all in the same vlan/same subnet. I am not clear what the options on the C921 are to accomplish that. If the interface on C921 connecting to ISP is a layer 3 routed interface then the suggestion by MHM to use BVI might be the way to go.