order of digit manipulation

Unanswered Question
Apr 11th, 2008


Could you please explain me the order of operation for following digit manipulation commnads:

no digit-strip


forwared digit


I have this problem too.
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smallrain_2 Fri, 04/11/2008 - 08:05

[English is not my native.]

Let me try again:

Assumed dial-peer is configured with all/combiantion of prefix, digit-strip, forward digit, and etc.

I want to know which command is tested/used before the others.


Kenneth Mohammed Fri, 04/11/2008 - 11:49

All of these commands are executed after the outbound dial peer is matched, and before the digits are sent out of the gateway to the pstn. The command that you decide to use on the dial peer is dependent on the type of behavior you would like the gateway to exhibit.

POTS dial peers, by default, strip any outbound digits that explicitly match their destination pattern. For example, given a destination pattern of 55512.. , the called number sent to the PSTN would contain just the last 2 digits. The first 5 digits would be stripped. To stop this behavior, you would use the command "no digit-strip".

The "forward-digits" command lets you specify the exact number of digits to be forwarded to the PSTN. If the number of digits presented exceeds the number allowed, the rightmost digits are sent. Here are some examples:

I want to dial 123-456-7890

In the below scenario, 456-7890 gets sent to PSTN

dial-peer voice 100 pots

destination-pattern 123456....

forward-digits 7

In the below scenario, 123-456-7890 gets sent out

dial-peer voice 100 pots

destination-pattern 123456....

forward-digits all

Lastly, in this scenario 7890 is sent

dial-peer voice 100 pots

destination-pattern 123456

forward-digits extra

The "prefix" commmand adds digits to the number before sending the call out of the gateway. Example: I want to dial 9-1-123-456-7890

dial-peer voice 100 pots

destination-pattern 91T

prefix 1

port 1/0:15

The original 9 and 1 digits are stripped, as they explicitly matched the destination pattern on the dial peer, and the 1 is prefixed to the remaining number, thus sending 1-123-456-7890 to the PSTN.

I hope that made sense to you.

smallrain_2 Fri, 04/11/2008 - 12:31

Your explanation make sense to me.

I have a few more questions:

Does forward-digits overwrite digit-strip?

Your example forward-digits forward everything without stripping anything.

What happen all prfix, forward-digits and digit-strip are configured? (not sure this was allowed)

for example:

dialed number = 123456

destination-pattern 123...

forward-digits 4

prefix 9

if order is digit-strip, prefix, forward-digits, the result woule be 9456

if order is digit-strip, forward-digits, prefix, the result would be 93456

I am not sure about order of the commands.

Please help


Kenneth Mohammed Fri, 04/11/2008 - 13:01

I just tried this in our lab, and it appears to work. So my belief at this point is the router should allow you to configure both forward-digits and prefix on the same dial peer. Like I said, all of these operations are performed after the outbound dial peer is matched and before the call is sent out the gateway.


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