G.703 interface

Unanswered Question
Feb 22nd, 2007

Hi,

the company i work for has to change its WAN infrastructure. Our provider (Deutsche Telekom AG) provides us 2 Mbit/s lines to all our locations in Germany and these lines are E1 with unstructured G.703.

Alternatively we had the possibility to chosse G.703 with G.704 framing, but we choose unstructured G.703.

I got these lines working with the VWIC2-1MFT interfaces. Cisco also offers the VWIC2-1MFT-G703 interfaces.

My opinion was, that for the unstructured G.703-leased lines, I need the VWIC2-1MFT-G703 interface, but the normal and cheaper VWIC2-1MFT also work.

I am happy about this, but i am wondering, for what I would need the -G703 interfaces?

Can anybody tell me the difference?

The normal VWIC2-1MFt seems also to with unstructured G.703 (E1). For what would I need the G703-interfaces?

Thanks for all information and best regards,

Florian

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Florian Zahn Mon, 02/26/2007 - 02:26

Hi,

thanks for your answer, but this is exactly what I am confused about:

This documents says, that for unstructured G.703 I would need the VWIC2-1MFT-G703 interface, but currently I run an unstructured G.703 with the VWIC2-1MFT (without -G703). I am wondering, why this is working...

Regards,

Florian

alexander.muhin Mon, 02/26/2007 - 08:03

Hi Florian,

>I am wondering, why this is working

Can you post "show controller E1" for that controller? Also show your config for the E1 controller.

IMO, unframed mode (G703) requires VWIC2-1MFT-G703 module.

regards,

Alexander

Florian Zahn Mon, 02/26/2007 - 08:12

Hi,

According to our provider, the lines are G.703 unstructred. We had the possibility to choose G.703 with G.704, but we did not.

Our configuration for unstructured E1-lines are:

controller E1 0/0/1

channel-group 0 timeslots 1-31

clock source internal

Then we have the Serial0/0/1:0 interface, which we configure for our lines.

The output of show controller E1 0/0/1 :

E1 0/0/1 is up.

Applique type is Channelized E1 - balanced

No alarms detected.

alarm-trigger is not set

Version info Firmware: 20040802, FPGA: 13, spm_count = 0

Framing is CRC4, Line Code is HDB3, Clock Source is Internal.

CRC Threshold is 320. Reported from firmware is 320.

Data in current interval (165 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Data in Interval 1:

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

...

Thanks for bringing light in the dark :-)

Best regards,

Florian Zahn

alexander.muhin Mon, 02/26/2007 - 08:36

With such configuration you are using framing (CRC4) mode. Therefore you have only 1.984 Mbps of available bandwidth.

To specify unframed mode for a controller E1 try the following example:

Router(config-controller)# channel-group channel-group-number unframed

The output should be like this one:

Router# show controller E1 1/0

E1 1/0 is up.

Applique type is Channelized E1 - balanced

Framing is UNFRAMED, Line Code is HDB3, Clock Source is Line.

PS. I think that such config is possible with G.703 card

hope this helps,

Alexander

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