Frame Relay Switch as Frame Relay Endpoint

Answered Question
Jan 10th, 2008

Hi everyone! I have one question concerning frame relay switching... Perhaps anyone could help me please with that?

So, the here is the task:

Router2(Serial0) - (Serial0)Router1(Serial1) - (Serial1)Router3

*Router1:*

frame-relay switching

interface Serial0

bandwidth 64

encapsulation frame-relay

clockrate 64000

frame-relay route 111 interface Serial1 101

!

interface Serial1

bandwidth 64

encapsulation frame-relay

clockrate 64000

no frame-relay inverse-arp

frame-relay route 101 interface Serial0 111

*Router2:*

interface Serial0

encapsulation frame-relay

!

interface Serial0.111 point-to-point

frame-relay interface-dlci 111

*Router3:*

interface Serial1

encapsulation frame-relay

!

interface Serial1.101 point-to-point

frame-relay interface-dlci 101

In this configuration Router2 sees Router3 and everything's good.

My question is: can Router1 act as frame relay endpoint to Router2 or Router3? Using the same physical interfaces, and achiving the goal somehow by configuring subinterfaces?

In general, I would like to establish multipoint connection from Router2 to Router1 and Router3. Is it possible?

I can rephrase my question in more theretical way... FR switch receives frames, extracts DLCIs from address field, compares them with switching table and forwards them out of some interface. How to tell FR switch that some frames are his and should be passed up the network stack for further processing?

Thanks in advance for any comments!

I have this problem too.
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Correct Answer by mounir.mohamed about 8 years 11 months ago

Look right now i don't have access to my Rack and there is an idea but i can not test it, also i can not remember my last test result for this case, but u can lab it up and test.

Only add the below configurations to your old config posted above.

On R1 (The Frame-Relay Switch)

*Router1:*

frame-relay switching

interface Serial0

ip address 1.1.13.1 255.255.255.252

frame-relay interface-dlci 13

frame-relay route 13 interface serial1 31

*Router3:*

interface Serial1

encapsulation frame-relay

!

interface Serial1.101 point-to-point

frame-relay interface-dlci 101

interface serial1.31 point-to-point

ip address 1.1.13.3 255.255.255.252

frame-relay interface-dlci 31

With The configurations above i'm trying to route frame-relay PVC from R3 to R1 and terminate it on R1 Serial0, and this will give you P2P PVC between R1 and R3 so now R1 acting as normal end point frame-relay router not FRSW only, but take care this for P2P only but for Multipoint PVC you have to install a new serial interface, Again this is just for test.

Besy Regards,

Mounir Mohamed

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mounir.mohamed Thu, 01/10/2008 - 12:11

As far as i understand, R1 now acting as FR-SW and you need it to particpate as FR end router like R2/R2, From my point of view, more physical interfaces should be installed, then you can create different PVC's between R1 and R2, R1 and R3, but again more serial interfaces should be used because the frame-route only supported under physical interfaces not logcal.

tar_mynastyr Thu, 01/10/2008 - 22:35

Thank you for the answer!

But I wonder, why it is so from the theoretical point of view? Or this is due to Cisco implementation only?

Could you explain your considerations, please!

Thanks a lot!

tar_mynastyr Thu, 01/10/2008 - 22:37

Thank you for the answer!

But I wonder, why it is so from the theoretical point of view? Or this is due to Cisco implementation only?

Could you explain your considerations, please!

Thanks a lot!

Sorry for double post. It's by accident...

Correct Answer
mounir.mohamed Thu, 01/10/2008 - 23:56

Look right now i don't have access to my Rack and there is an idea but i can not test it, also i can not remember my last test result for this case, but u can lab it up and test.

Only add the below configurations to your old config posted above.

On R1 (The Frame-Relay Switch)

*Router1:*

frame-relay switching

interface Serial0

ip address 1.1.13.1 255.255.255.252

frame-relay interface-dlci 13

frame-relay route 13 interface serial1 31

*Router3:*

interface Serial1

encapsulation frame-relay

!

interface Serial1.101 point-to-point

frame-relay interface-dlci 101

interface serial1.31 point-to-point

ip address 1.1.13.3 255.255.255.252

frame-relay interface-dlci 31

With The configurations above i'm trying to route frame-relay PVC from R3 to R1 and terminate it on R1 Serial0, and this will give you P2P PVC between R1 and R3 so now R1 acting as normal end point frame-relay router not FRSW only, but take care this for P2P only but for Multipoint PVC you have to install a new serial interface, Again this is just for test.

Besy Regards,

Mounir Mohamed

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