PPP over Ethernet 2

By Chris July 19, 2016 13:05

Configuring PPPoE may seem scary, but it is not too hard from a practical sense. The complex part is understanding each command, and the even more complex part is connecting the configuration to the underlying ideas shown in the related show commands. But the first step is mastering the configuration, and this lab helps with that first step. This lab lets you choose the client-side PPPoE configuration, and gives you another rep on getting good at that config.


This lab assumes that you might want to try this lab exercise on your own gear, VIRL, or on a simulator. To that end, the lab can use a crossover cable between the router acting as the PPPoE client router and the ISP router. These two routers would normally sit in different buildings, one owned by the customer and one owned by the ISP, with DSL or some other technology for an Internet access link between the routers. In a lab, to test the PPPoE configuration, the two routers just use an Ethernet link.

For this lab, build a client-side PPPoE configuration to match the following requirements. You do not need to worry about the ISP configuration at all, but it is listed in Example 1 for reference. The specific rules for this lab – all for the client router – are as follows:

  • Use the Dialer 20 interface
  • Use the Dialer Pool number 10
  • Configure the client to dynamically learn it’s IPv4 address on the PPPoE link using PPP protocols (it should learn if you try this in lab, per the ISP router’s initial configuration)
  • Configure the MTU to a value that considers the extra PPPoE headers
  • Use the ‘Cert’ Authentication hostname and ‘Skills’ Authentication password. (The username/password combination is pre-configured; see Example 2 in this post.)
  • Configure a default route using the Dialer 20 interface as the outgoing interface
  • Assume all device interfaces shown in the lab are up, working and with correct IP addresses assigned (except for the Client interface connecting to the ISP).

Figure 1: Typical Lab Network for Testing PPPoE Configurations


Initial Configuration

Examples 1 and 2 show the beginning configuration state of ISP and Client devices.

Example 1: ISP Config

Example 2: Client Config


Answer on Paper, or Maybe Test in Lab

Next, write your answer on paper. Or if you have some real gear, or other tools, configure the lab with those tools.

To test your solution, if you happen to try it with CML/VIRL or real gear, you can verify the configuration and operation of the dialer interface by issuing the show interfaces dialer 10 command, you can verify the connectivity to the ISP by using the ping command. Also, on the client, try: show interfaces virtual-access 10, show interfaces virtual-access 10 configuration, and show pppoe session.


Do this Lab with Cisco’s CML (Formerly VIRL)

You can do these labs on paper and still get a lot out of the lab. As an extra help, we have added files for Cisco Modeling Lab – Personal (CML-P). CML-P replaces Cisco Virtual Internet Routing Lab (VIRL) software, in effect serving as VIRL Version 2.

Below, find two files: a file useful with CML-P and another useful with VIRL. (Note that the CML-P file has a .yaml filetype, while the older VIRL file has a VIRL filetype.) Once the file is loaded, CML-P or VIRL will create a lab topology similar to this lab’s topology, with the initial configuration shown in the lab as well.

This lab’s CML file!

This lab’s VIRL file!

The CML/VIRL topology matches this lab topology exactly.

Answers: GRE Tunnel 2
Answers: PPP over Ethernet 2
By Chris July 19, 2016 13:05
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