Is this a Lease line or Frame-relay circuit?

Unanswered Question
Apr 6th, 2008

My telco Verizon told me that the link between my CE and PE is a lease line but my CE router is using encapsulation frame-relay configuration. My question to verizon is that is this a frame-relay circuit or lease line? They replied is a lease line but encapsulated with frame-relay. But my question to them is if is a lease line then how come I cannot use PPP or HDLC? and frame-relay is using DLCI circuit but lease line is not so how can this be a lease line? They did not reply my question on this. My next question is since this is a lease line then I can configure it with PPP or HDLC. They replied can, but I need to submit a change for the PE router too. The frame-relay is a standard configuration verizon used to connect between my PE and CE all over my downstream routers and then connected to MPLS cloud. I really hope to find out how is it possible to configure a frame-relay configuration with a lease line? Even on the CCIE lab, you still need a Frame-relay switch in between to make frame-relay works so how can this be a lease line circuit. I do not have proof to make my concepts right but I really hope to find out more. Please enlighten me. Thanks.

interface Serial0/0

description 512k to IP-VPN

no ip address

max-reserved-bandwidth 95

encapsulation frame-relay

load-interval 30

no fair-queue

frame-relay traffic-shaping

frame-relay lmi-type ansi


Current configuration : 247 bytes


interface Serial0/0.1 point-to-point

description Connecting to Verizon 2M MPLS to internet

ip address

backup delay 5 10

backup interface Dialer0

frame-relay interface-dlci 100

class xyz


map-class frame-relay xyz

frame-relay cir 486400

frame-relay bc 4864

frame-relay be 0

frame-relay mincir 486400

service-policy output ip-vpn

policy-map ip-vpn

class silver

bandwidth 256


class class-default



I have this problem too.
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Danilo Dy Sun, 04/06/2008 - 22:06


Leased-lines are dedicated circuits. There are many types of leased-lines (media, interface, encapsulation): E1, E3, T1, DS3, OC, and FRAME-RELAY.

If you need a specific leased-line, you need to ask the provider for it. However, sometimes it depends on the following which could be the reason they provide you FRAME-RELAY (if you didn't ask for specific type).

- Bandwidth

- Provider infrastructure available at your end (or both ends).



mohammedmahmoud Sun, 04/06/2008 - 23:18


Nowadays, the Leased line word seems to be very vague, in the past you could have rent a dedicated circuit between your 2 sites (physical link) and have your desired layer 2 encapsulation (FR, PPP, HDLC, ...) between your CEs directly, this was a pure leased line. As for your case the local loop between your site and the PoP that contains your SP PE is what they call a leased line, afterwards your traffic is packet switched (or label switched, or whatever based on the SP backbone) to your other end over the provider backbone. I believe that since a PE router is included in your setup thus your provider is providing you the FR link over AToM, in order to change the layer 2 encapsulation you need to inform your provider since the layer 2 encapsulation is between your CE(s) and his (PEs) then the PVC(s) is configured end-to-end over his MPLS backbone.

I hope that i've been informative.


Mohammed Mahmoud.

Richard Burts Mon, 04/07/2008 - 04:24

Seng seems to be operating from an assumption that Frame Relay and leased line are mutually exclusive (it can be one or the other but not both). However this assumption is not correct. It is quite possible for a leased line to use Frame Relay encapsulation. It appears from his post that this is the case.

In my experience it is fairly common for Internet providers to use Frame Relay encapsulation for point to point leased lines from the customer to the provider Point Of Presence. As long as the traffic gets from the Customer Edge (CE) to the Provider Edge (PE) I am not sure that it is significant what encapsulation is used.


Is there some problem here or is this just a question about concepts?



Rick Morris Mon, 04/07/2008 - 10:11

Verizon - the old MCI folks love Frame Relay...use to work there.

It is a way to save bandwidth. They do this because they know that not everyone will be using all their bandwidth at the same time, so Frame Relay is best effort Bandwidth. You share it. What they do is provide you a point to point T-1 and run it through their frame relay cloud and map the link directly as a leased line would be. This is also a way to have multiple T-1's running in the Frame Relay cloud and not have multiple T-1's coming back in your HQ.

For instance.

We had 5 clients running 128k frame back into our Main HQ as the Hub. We had one T-1 into our office and all 5 were built on the 1 T-1 into sub interfaces on the router.

When you sign the contract you are given a CIR, but still with Frame Relay not a guarentee.


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