Introduction to Frame-Relay for CCNA Students

Hi Muhammad,

You are right, I should change the picture :wink:


Hi Rene,

Really a gr8…explanation. Now I understand actual Frame Relay concept…Thanks once again,

I think now in Network MPLS is used instead of Frame Relay…may be I have wrong…but please explain me difference between this MPLS vs Frame Relay…?

Waiting for your reply,

Imran Ghumara

Hi Imran,

Frame-relay is pretty old and you won’t see it in networks anymore. MPLS is very popular nowadays but it’s a completely different protocol compared to frame-relay…hard to explain in a few sentences here. I’ll write some more tutorials on MPLS in the future to explain it.


Thanks but give also the configuration parameters under frame relay

You are welcome iLeana and thanks :slight_smile:

The configuration examples for point-to-point and point-to-multipoint are here:

Thank you so much rene,ur article made me to master 60% of frame relay next configuration…

I think we cannot be more clear about basics of frame relay

thanks rene.
great explantion.

I felt how many times had you concerned about easily teaching! On reading your Introduction, I understood at one time.


Thanks that answered a lot of my questions.


Can u explained the steps involved after u completed and order for a VC.
What is the service provider obligation/responsibilities to get the VC up and running for u?
What equipment will they installed on ur premise? What cables will they run to ur premise?

Hi Raymond,

To be honest, I never worked with frame-relay on a production network here :slight_smile: It’s pretty old and here in the Netherlands a lot of companies switched to DSL / fibre / cable around 2000.

The installation is similar to any other link that you would get today (Fibre perhaps). The ISP takes care of the cabling and normally supplies the customer with a router for each site. These routers are normally managed by the ISP and you are not allowed to change the configuration.

Routers nowadays have WIC modules with an integrated CSU/DSU, older WIC modules so you needed a separate modem that was connected to your router. About the cabling, frame-relay supports a lot of different cabling options…copper and fibre.



Someone can explain me what is the relationship between the DE and the CIR in Frame Relay?


Hi Dominik,

The CIR rate is the committed rate, in other words the rate that the ISP guarantees that you will get.

The DE bit indicates that the frame has a lower importance. When there is congestion, the frames with the DE-bit set can be dropped.

Normally, all frames that exceed the CIR rate will have their DE-bit set so that’s the relationship between the two.



when HQ and sites are connected through physical serial interface. what is the use of virtual circuit(logical).
is it just to provide DLCI num

Hello Dheeraj!

As you mentioned correctly, the virtual circuit is a logical connection between two DTE (Data Terminal Equipment) devices within the framework of a Frame Relay implementation.

Regardless of how many physical serial interfaces you have connected to the frame relay network, you still require a virtual circuit for each logical connection. In other words, if you only have one physical serial interface, and you only have one virtual circuit connecting to a remote device via a frame relay connection, then you still require the virtual circuit. The virtual circuit is what defines the connection (via the DLCI as you mentioned) and the physical interface just provides the “pipe” through which the DTE connects to the network.

I hope this has been helpful!


19 posts were merged into an existing topic: Introduction to Frame-Relay for CCNA Students

Is it possible to do the lab in unetlab

Can you explain the below

If you use point-to-point it will solve your split-horizon problem but you’ll need to use a different IP subnet per PVC. Point-to-multipoint means you have the split-horizon problem but you can use a single IP subnet for all PVCs.