Hub and spoke frame relay enviroment for lab

Answered Question
Jun 6th, 2008

Hi

i am trying to set up a frame relay hub and spoke topology in my home lab

i have two 2600 routers with wic-1t cards and a one 2520 frame relay router

My question how do i connect them physically back to back with a db60

dce/dte cable to make a hub and spoke network

should it be one physical connection with db60 cable from 2520 router which acts as a hub to the one 2620 router or two physical connection from 2520 to the the two 2620 routers

please advice

Thanks

I have this problem too.
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Correct Answer by Kevin Dorrell about 8 years 5 months ago

Hi,

When I think of a hub-and-spoke topology in the lab, I usually think of four routers rather than three. One of the "routers" - the 2520 - would act as a frame-relay switch, not as a router. Let us call that box "FRS".

Let us call the other three routers R1, R2, and R3. You could connect R1 to FRS-S0, R2 to FRS-S1, and R3 to FRS-S2. You do this with three DB60 back-to-back cables, with the DCE ends on FRS, and the DTE ends on your routers.

Now decide which router is the hub, say R1. Make two frame-relay PVCs: one R1<-->R2, and one R1<-->R3. There you have a hub-and-spoke topology with R1 as the hub.

You could, I suppose, eliminate the frame-relay switch by configuring the links back-to-back, but that is not the usual way to set it up in the lab - nor in real life. I suspect you would then be spending more time trying to get the back-to-back connections working than studying hub-and-spoke. And in any case, if you are using this to study for an exam I fear it might too different from the standard topology, and might cause confusion.

If I were you I would try and get a third 2620.

Kevin Dorrell

Luxembourg

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sdoremus33 Sat, 06/07/2008 - 08:33

I recently set up a home lab using the following config

Hub Router --> Csco 3620

Spoke(1)--> Csco 3620

Spoke(2)--> Csco 3620

Frame Relay Switch -->Csco 2514

I basically set up the following env.

Hub-(2)Spoke setup

where rtr1--> Hub rqan ptomp

and teo spokes ran physical interfaces back to Hub

In this scenario remember the following confiuratiion

1)In Physiclal or PtoMPFrame-Relay connections when inverse-arp is not an option you need to use the Frame-Relay map command Ex

Frame-Relay map ip brodcast

In PtoP environments you use the Frame-relay dlci command (See Below)

Frame-relay interface dlci

I connected the DCE end to the Frame-Relay switch, and the DTE to each Frame router.

To verify the connection issue the following cmd (See Below)

sh controllers serial

The third line down or so will show you your connection and clock rate

Remember on DCE connection Frame-Relay i used the following configalong with other Frame-Relay configuration (See Below)

config t

Frsme-relay intf-type DCE

clock rate 64000.HTH

gurkamal01 Sat, 06/07/2008 - 16:57

Hi

thanks for your help

what i have in my lab is a one 2520 router and 2 2620 router

what i am asking is how many back to back dte/dce connection from the serial int of the the 2520 router do i need to connect to the two 2620 routers to make a frame relay enviroment

Is it s0 of 2520 connects to the s0/0 of 2620 thru serial cable and also s1 of 2520 connects physically to the s0/0 of the second 2620 router

Or we need just need one physical connection fron 2520 to the any 2620 router

please help

Edison Ortiz Sat, 06/07/2008 - 17:15

Is it s0 of 2520 connects to the s0/0 of 2620 thru serial cable and also s1 of 2520 connects physically to the s0/0 of the second 2620 router

That should cover it.

__

Edison.

Correct Answer
Kevin Dorrell Sat, 06/07/2008 - 23:40

Hi,

When I think of a hub-and-spoke topology in the lab, I usually think of four routers rather than three. One of the "routers" - the 2520 - would act as a frame-relay switch, not as a router. Let us call that box "FRS".

Let us call the other three routers R1, R2, and R3. You could connect R1 to FRS-S0, R2 to FRS-S1, and R3 to FRS-S2. You do this with three DB60 back-to-back cables, with the DCE ends on FRS, and the DTE ends on your routers.

Now decide which router is the hub, say R1. Make two frame-relay PVCs: one R1<-->R2, and one R1<-->R3. There you have a hub-and-spoke topology with R1 as the hub.

You could, I suppose, eliminate the frame-relay switch by configuring the links back-to-back, but that is not the usual way to set it up in the lab - nor in real life. I suspect you would then be spending more time trying to get the back-to-back connections working than studying hub-and-spoke. And in any case, if you are using this to study for an exam I fear it might too different from the standard topology, and might cause confusion.

If I were you I would try and get a third 2620.

Kevin Dorrell

Luxembourg

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