Frame Relay and the issues with Cisco IOU

As part of the big lab I am doing I want to do some work with Frame Relay. Nothing too exciting at the moment, but I do want to touch on it.

So with IOU I want a Frame Relay connecting to four other routers in a hub and spoke topology. Pretty simple right?

Well using this netmap:

5:0/0 1:0/0
5:0/1 2:0/0
5:0/2 3:0/0
5:0/3 4:0/0

I get what I want:
Frame relay hub and spoke

Frame Relay basic configuration

I can set up my FR switch as follows:

hostname FR1
!
boot-start-marker
boot-end-marker
no aaa new-model
clock timezone CET 1 0
mmi polling-interval 60
no mmi auto-configure
no mmi pvc
mmi snmp-timeout 180
ip auth-proxy max-login-attempts 5
ip admission max-login-attempts 5
ip cef
no ipv6 traffic interface-statistics
no ipv6 cef
frame-relay switching
multilink bundle-name authenticated
crypto pki token default removal timeout 0
redundancy
!
interface Serial0/0
 description Connected to R1
 no ip address
 encapsulation frame-relay
 no keepalive
 serial restart-delay 0
 no frame-relay inverse-arp
 frame-relay lmi-type ansi
 frame-relay intf-type dce
 frame-relay route 102 interface Serial0/1 201
 frame-relay route 103 interface Serial0/1 301
 frame-relay route 104 interface Serial0/1 401
!
interface Serial0/1
 description Connected to R2
 no ip address
 encapsulation frame-relay
 shutdown
 no keepalive
 serial restart-delay 0
 frame-relay intf-type dce
 frame-relay route 201 interface Serial0/0 102
!
interface Serial0/2
 description Connected to R3
 no ip address
 encapsulation frame-relay
 no keepalive
 serial restart-delay 0
 frame-relay intf-type dce
 frame-relay route 301 interface Serial0/0 103
!
interface Serial0/3
 description Connected to R4
 no ip address
 encapsulation frame-relay
 no keepalive
 serial restart-delay 0
 no frame-relay inverse-arp
 frame-relay lmi-type ansi
 frame-relay intf-type dce
 frame-relay route 401 interface Serial0/0 104
!

Ok, so nothing too complicated here.

Looking at R1 and R4 (truncated):

hostname R1
!
interface Serial0/0
 no ip address
 encapsulation frame-relay
 serial restart-delay 0
 frame-relay lmi-type ansi
!
interface Serial0/0.14 point-to-point
 ip address 10.1.14.1 255.255.255.0
 frame-relay interface-dlci 104   
!

hostname R4
!
interface Serial0/0
 no ip address
 encapsulation frame-relay
 serial restart-delay 0
 frame-relay lmi-type ansi
!
interface Serial0/0.41 point-to-point
 ip address 10.1.14.4 255.255.255.0
 frame-relay interface-dlci 401   
!

I should be able to ping R4 from R1 and R1 from R4, but “sh ip int bri” shows that the sub-interfaces are down/down and the physical interface is up/down. If I add “no keepalive” to the physical interfaces they come up, but I still can’t ping across them:

frame relay
So the config looks ok, the interfaces are up, and we know from part two of the big lab series that serial interfaces do work on IOU, so what’s the problem? Well it looks to be an issue in IOU:

frame relay show interface

DCE and DTE

Look at the result of the “sh int serial 0/3”, it clearly shows that its set to Frame Relay DCE, but the result of the “sh controllers serial 0/3” shows a very different story:

frame relay show controllers

It’s showing a cable type of DTE.

Having a look at the netmap tutorial on Route Reflector page it shows a Frame Relay switch sitting in the middle of a bunch of routers and the netmap has 107 at the end of the connections, 107 being the Link-Layer header type for Frame Relay. So if I change my netmap to:

5:0/0 1:0/0 107
5:0/1 2:0/0 107
5:0/2 3:0/0 107
5:0/3 4:0/0 107

I get this:

frame relay iou

Clearly, this is not what I am looking for!

Means I have to rethink how my big lab topology will pan-out. I am guessing it’ll be without Frame-Relay for the time being! Even Andrea over at Route Reflector states that serial interfaces appear as DTE in the FAQs.

If anyone knows how to get around this, I’d love to hear from you. I have tried a number of different images but so far nothing works.

I am going to continue playing around, so hopefully will be able to pull something out of the hat, unless there is someone out there that can point me in the right direction…

*Update* GNS3 works fine with the same configs.

7 Comments

  1. Anonymous November 6, 2014
  2. Stuart Fordham November 6, 2014
  3. David June 25, 2015
  4. NN June 25, 2015
  5. Stuart Fordham June 25, 2015
  6. Stuart Fordham June 25, 2015
  7. Reuben April 7, 2018