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Community Member

Qsig & Partial Rerouting


We have a customer that has the following problem:

Their fixed telephony to cell phones is going outbound using a telco line, they don't want use that telco anymore so the numbers were transferred to a different telco.

Everything was fine untill a point where calls that are inbound to fixed cisco phones, where the phones are transferred to a cell phone. They then get the did from the main site and not the DID from the cell phone.

The Telco suggest "Partial Rerouting" because they don't support QSIG to get this resolved, but when opening a tac case with cisco to listen of "Partial Rerouting" is possible on a cisco device, they say it's not possible.

Anyone have a suggestion on how we can proceed further on this?


Hall of Fame Super Gold

Qsig & Partial Rerouting

What is "partial rerouting" ? Can you specify the relevant technical standard ?

Anyway, what you found  is normal and often asked had you searched before asking. Telco does not allow calls to be made with number different that your own, otherwise that would mean you can spoof caller-ID at will.

Community Member

Qsig & Partial Rerouting


There are telco's in this country (belgium) that accept a CLIP sent by the customer. So for example if you have an office with a fixed cisco phone that does a transfer to a cell phone. And someone calls that fixed phone then they see the number of the cell phone instead of that fixed number.

This telco doesn't accept this and they offer partial rerouting, i will look more into the specifics with the telco itself. The telco does not support QSIG,

The customer itself does want to swap to the same provider for all their lines and perhaps we can try this again with a SIP trunk

Hall of Fame Super Gold

Qsig & Partial Rerouting

I think you will find that no SIP provider will allow a CLIP that is not allocated to you.

If you can detail what exactly is "partial rerouting" according to telco, that can be looked into.

Community Member

Re: Qsig & Partial Rerouting

Hi there,

Partial rerouteing is a term used in QSIG networks. See ECMA-174 standard paragraph 4.2.17. It is the ECMA standard on the call diversion supplemantry service. Basically the transferring party (B)indicates to the transferred party (A) that it can call the transfer-to party (C) directly and thus replacing the call legs A to B and B to C by a call leg from A to C.

One still needs to support QSIG in order to send/receive/interpret the Facility IE containing the callRerouteing suppl. service. So I would think that if the telco is not supporting QSIG that this partial rerouteing won't work either. As far as I know, IOS does not support QSIG but CUCM does!

But that doesn't help you. If the transferring party is an IOS gateway, you might try to enable :

interface serial 0:15

  isdn outgoing ie redirecting_number

Some service providers take that into account and present the original calling number and the redirecting number. Belgacom does for example :-)

As we live in the same country, talking might be easier...



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