dor
Registration Date: 01.01.1970
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17.07.2008 19:44 |
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i-p
Super Moderator
Registration Date: 14.01.2006
Posts: 4792
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17.07.2008 21:37 |
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dor
Registration Date: 01.01.1970
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RE: CID doesn't pass to provider |
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Zitat: |
Originally posted by i-p-tel
Writing the above mentioned $-Codes into the trunk is not static, and did you try leaving “My Name” of your classical extension empty? |
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Guys, there’s definitely a problem here. Since putting <1${DOLLAR}{CALLERIDNUM}> into trunk’s outbound CID resolved the problem only partially, I went to provider again for some more extensive testing.
Here’s what’s happening, and please note – incoming CID from DID provider is always looks as “Doronin Test” <5141111111>, 10 digits.
If I don’t set trunk’s outbound CID at all, provider receives the following: name and URI, as you can see number 5141111111 isn’t sent there at all.
From: "Doronin Test" <sip:188778888@sip.callwithus.com>
If I set trunk’s outbound CID to <${DOLLAR}{CALLERIDNUM}>, with no any prefix, it eliminates the name part from CID, and provider receives the following:
From: "5141111111" <sip: 188778888@sip.callwithus.com>
As you can see number 5141111111 goes instead of the name, and again URI sent instead of the number. In this case provider picks CID from name field, and this is why it appears to work sometimes. It has nothing to do with e164
To confirm the above, I set trunk’s outbound CID to "Doronin Test" <${DOLLAR}{CALLERIDNUM}>
As expected, provider received again only name part and URI
From: "Doronin Test" <sip:188778888@sip.callwithus.com>
Guys, all this caused by the fact that PBXes always send URI like <sip:188778888@sip.callwithus.com> instead of the number. Now I can understand all weird results I see in other providers call monitor lists. It would be much helpful if you fix it to send CID in its original form.
Thanks!!
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18.07.2008 16:27 |
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i-p
Super Moderator
Registration Date: 14.01.2006
Posts: 4792
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18.07.2008 20:20 |
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Dia
Premium Account
Registration Date: 03.03.2006
Posts: 1443
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Some background info regarding SIP and the Off-Net realm |
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We should keep in mind when the SIP protocol was conceived, it was designed to allow ubiquitous communications (voice, video, messaging) between users of broadband networks. SIP was not designed or intended as an ISUP or SS7 replacement, which are the underlying protocols of the PSTN telephone system worldwide.
Through its' versatility, expandability and flexibility the SIP protocol is currently able to handle most of the ISUP call flows natively, almost all of the PSTN features we take for granted today, as well as the advanced functionality it was designed for initially, which should follow us well in the future. Regarding the rest of the PSTN centric and the GSM / 3G centric ISUP messages, the SIP-T and SIP-I standard extensions were introduced, to handle them properly and to allow interoperation with the legacy telephone networks.
So when making bold claims, the SIP URIs should have been this way or the other, a lot of carefully selected choices and details are glossed over, for questionable gains which can be achieved via other means. SIP URIs resemble email addresses, so messages between them can be exchanged using similar methods email messages employ. Phone numbers are notations of the PSTN world, which were carried forward into the SIP realm to make it intuitive for us to use, but they are not essential to communicate as they were in the PSTN realm.
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19.07.2008 05:32 |
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dor
Registration Date: 01.01.1970
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20.07.2008 05:20 |
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Dia
Premium Account
Registration Date: 03.03.2006
Posts: 1443
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Zitat: |
Originally posted by doronin However, as a software developer myself, I'm having hard time to understand why would you make your customers to do this kind of effort to merely find a way to pass CID in a form that is "standard" to "real world" providers. |
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Well, we didn't design the SIP protocol or how it interacts with ISUP, the underlying PSTN protocol. We didn't create the various SIP Proxies available, or run the ITSPs who provide us with SIP Trunks to call PSTN numbers.
On the other hand, keep in mind that you can't pass the CallerID you desire with any of the "real world" providers, namely the telcos who use TDM Class-5 switches. When you Call Forward your fixed line at home to your mobile phone, there is no way the "real world" telco will display the CallerID of the original inbound call to your home PSTN line, but the displayed number on your mobile will be your home number.
All this functionality became available with VoIP telephony, precisely because the telephone numbers are no longer essential to the underlying process for communication between users of the network.
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29.07.2008 00:54 |
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