FRF.15 and FRF.16

Unanswered Question
Jan 2nd, 2009


both the FRF.15 and FRF.16 looks same as far as the functionality is concern, so what are the differences in there at configuration level as well as theory level?


Devang Patel

I have this problem too.
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Giuseppe Larosa Sat, 01/03/2009 - 07:07

Hello Devang,


The Frame Relay Forum has created two different


• FRF.15: This covers the end-to-end mode. The CPE does the MLFR

protocol and uses standard UNI on multiple T1 lines into the service

provider. The service provider has no knowledge of the MLFR. Of

course, being end-to-end means that each MLFR bundle can only talk

to one endpoint.

• FRF.16: This standard covers the UNI and NNI interfaces for MLFR.

Once in the providers network the traffic can be routed on other

MLFR bundles or higher speed links. The terminating enterprise can

also be on an MLFR bundle or a high speed link. And because the

bundle terminates at each network interface, different endpoints via

multiple PVCs on each bundle can be supported

Hope to help


devang_etcom Sat, 01/03/2009 - 10:25


I read the same slides from ipmpls forum and got bit confuse thats why I asked this question on this forum! but thanks for your time!


Devang Patel

Giuseppe Larosa Sat, 01/03/2009 - 13:23

Hello Devang,

the pictures in the following pages are more clear to me:

with FRF.16 (that actually is the one I know more) the service is provided by the service provider that is aware of the bundle so you have a UNI (DTE) to NNI (DCE) communication for setting up the bundle.

The advantage is that on other nodes the PVCs can be carried over whatover type of FR (or ATM) link.

FRF.15 is instead a sort of private bundle performed end-to-end between the routers.

In this case the service provider just provides some E1 links (circuit switching) and it is not aware of the bundle.

On the other hand all links have to be E1.

In some way FRF.15 is more similar to what happen with PPP multilink where you can bundle two E1 and the configuration is end-to-end (WAN switches in the middle just cross connect the E1 links).

For example we have a PPP bundle of two E1 and each E1 is provided by a different provider,

Hope to help


devang_etcom Sat, 01/03/2009 - 16:11


So I can say that FRF.16 is more flexible for service provider as they just need to worried about CE to PE connectivity for bundling after PE they can have any kind of connectivity right?


Devang Patel

Giuseppe Larosa Sun, 01/04/2009 - 02:30

Hello Devang,

yes FRF.16 handles the multilink on PE to CE only, and then the single FR PVCs can be carried over whatever type of link the service provider can use.

Actually, FR multilink is normally associated to FRF 16 or 16.1.

Hope to help



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