Simulate frame relay subinterfaces in lab

Unanswered Question
Aug 4th, 2007
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I have the following setup on a router to a DR site and I would like to simulate this in a lab environent.

The connection is a DS3 and is frame relay.

Is there any way to simulate this on a regular point-to-point T1 connection with a crossover cable from WIC T1 CSU/DSU to WIC T1 CSU/DSU?

I know I can simulate frame-relay with a third router, but I was hoping to do something with just a point-to-point and two routers.

The existing config is this on one side:

interface Serial1/0

description connected to DS3

no ip address

encapsulation frame-relay IETF

ip route-cache flow

load-interval 30

dsu bandwidth 44210

framing c-bit

cablelength 50

clock source internal

serial restart-delay 0

frame-relay lmi-type ansi

frame-relay intf-type dce


interface Serial1/0.4 multipoint

description Bridge VLAN 4

frame-relay map bridge 4 broadcast

frame-relay interface-dlci 4

bridge-group 3


interface Serial1/0.100 point-to-point

ip address

frame-relay interface-dlci 100


interface Serial1/0.101 multipoint

description Bridged VLAN 5

frame-relay map bridge 101 broadcast

frame-relay interface-dlci 101

bridge-group 1


interface Serial1/0.250 multipoint

description Bridge VLAN 2

frame-relay map bridge 2 broadcast

frame-relay interface-dlci 2

bridge-group 2

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Overall Rating: 5 (4 ratings)
l.monje Sat, 08/04/2007 - 18:07
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As long as I know you can connect 2 wics CSU/DSU back to back, you just need to make a crossover cable, you can find the pin-out at

About the Frame-relay configuration check this link

there are the configs to setup a frame-relay lab with two routers in the above link, and in the link below you will find the way to config the cross cable.

Let us know how works the lab!!!

Richard Burts Sat, 08/04/2007 - 20:44
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It certainly is possible to set up 2 routers with a back to back serial connection and to configure the link as frame relay. But since there is no device to provide the Frame Relay switching, the ability to really emulate Frame Relay is pretty limited. I am not clear from your description how closely and exactly you need to emulate the Frame Relay environment.

Your configuration has 4 subinterfaces (with multipoint and point to point). You might be able to emulate 1 of the point to point but I think you can not really emulate the multipoint. And I do not believe that 1 router back to back can possibly emulate 4 subinterfaces.



royalblues Sun, 08/05/2007 - 00:13
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As Rick said, you need to configure frame-relay switching and also specify the DCE terminal

Here is what i do for a lab but again the capabilities are limited


frame-relay switching

int serial 2/0

encap frame-relay ietf

frame-relay lmi-type ansi

frmae-relay intf-type dce

int serial 2/0.16 point-to-point

ip address x.x.x.x y.y.y.y

frame-relay interface-dlci 16

router 2

int serial 1/0

encap frame-relay ietf

frame-relay lmi-type ansi

int serial 1/0.16 point-to-point

ip address x.x.x.x y.y.y.y

frame-relay interface-dlci 16




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