FR speed management

[ohassairi]

Hello

If  service provider is providing FR services

Now for each DLCI there is one CIR, Bc (commited burst) and Be (excess burst)…

1-How do they configure these parameters in FR switches? Do they make traffic policing in the entry to FR cloud ? or shaping ? or nothing?

2-the FECN and BECN how they are triggered by FR switch?

Is there any config example from SP side ?

[paolo bevilacqua]

They can do anything of the above, and perhaps some more, depending on their policies and decisions.

And there is no way of knowing beside careful observation, or direct information.

[Joseph W. Doherty]

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Posting

For #1, normally the FR provider will police your traffic at the CIR rate.  Frames that exceed CIR (and not already marked discard eligible[?]) are marked discard eligible.

For #2, when a FR switch detects link congestion, it tags the frames with FECN.  When the PVC receiving router receives the FECN tagged frames, there's an option to reflect the FECN on outgoing frames as BECN.  The PVC sending router can shape (slower) its transmission rate when it detects the BECNs (the reflected FECNs).

NB: in theory, the FR switch when it tags a frame with a FECN might tag opposite flowing frames with BECN, but it both needs to know the opposite flowing frame is going to the source and there would be need for a frame for it to piggy back upon (don't believe it will generate frames).  (Been years since I've worked with FR, but don't recall seeing BECNs unless I reflected FECNs.)

Don't have any configuration examples as they would be specific to frame-relay switch type.

[ohassairi]

thanks josef

you said : Don't have any configuration examples as they would be specific to frame-relay switch type

do you mean that in practice we don't use cisco devices as frame relay switches?

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

ohassairi wrote:
 thanks josef
you said : Don't have any configuration examples as they would be specific to frame-relay switch type
do you mean that in practice we don't use cisco devices as frame relay switches?

Correct, I don't believe they do.  Believe they are dedicated devices.

However, if you want to see how a Cisco router can be used to do frame-relay switch emulation in a lab, you can search the Cisco site for papers and examples how to configure that.