Config Museum: Frame Relay IP Configuration

By certskills May 7, 2012 08:15

This blog post can be a stand-alone lab, but it is also a continuation of an earlier museum piece. The earlier lab asked you to configure Frame Relay, without the IP addressing. This lab adds the IP Addressing details to the picture. So, this lab’s starting point is the previous lab’s ending point.

As usual with these Config Museum pieces, it’s a lab, no guile, no tricks, but just a straightforward chance to practice. Enjoy!

Initial State: Working Interfaces, No IP

This lab begins with a Frame Relay design, with the physical interfaces and subinterfaces configured. At this point, the routers should show both the physical and subinterfaces up, and the PVCs show up as “active” in the output of the show frame-relay pvc command.

This lab begins with the design shown in Figure 1, and the configuration on the routers as shown in the three examples that follow the figure.

Figure 1 – Frame Relay Configuration Details

Example 1: R1 Initial Config


Example 2: R2 Initial Config


Example 3: R3 Initial Config


Today’s Problem: IP Design and Config

For today’s lab, you need to add IP addressing. Part of the lab lets you practice your IP addressing math, and part lets you think about where to add IP addressing configuration for Frame Relay.

The biggest challenge with Frame Relay IP configuration relates to some of the design issues, and how those translate to where you configure the IP addresses. This lab attempts to give you enough room to think about those details, without it just being a completely open-ended exercise.

To that end, the following list details all the requirements for IP addressing on Frame Relay. Partly you have to do so IP addressing and subnetting design to pick subnets and pick IP addresses. At that point, you need to create additional configuration for all three routers.

Also, note that the figure shows the IP subnets for the three LAN subnets in the design, so refer to the figure, with some details in the list, to figure out the LAN interface IP configuration for this lab.

The following list details your rules for what to configure.

  1. Choose Subnet(s) for the Frame Relay part of the network, based on your reading of the figure and the initial configuration.
  2. Use the smallest subnets possible, that is, the subnet(s) with the fewest host IP addresses.
  3. Use the smallest number of subnets possible that will work. For example, if you can make the Frame Relay addressing work with 1 subnet, use 1; if at least 2 are required, use 2; if at least 3 are required, use 3.
  4. Use subnets that begin with “10.2”, and use the numerically-lowest subnets in that range.
  5. Router R1 gets the numerically lowest IP address in each subnet to which it connects.
  6. R2 and R3 get the numerically highest IP address in each subnet to which it connects, but if they connect to the same subnet, R3 gets the highest address, and R2 gets the next highest.
  7. Create the router configuration for all three routers, for IP addressing.
  8. Use defaults if possible
  9. Assume the interfaces all already work – in other words, they are in an up/up state

That’s it! Enjoy!

Answer, Config Museum: Frame Relay
Mask Conversion: Quick Draw McGraw or Quick Claude?
By certskills May 7, 2012 08:15
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