[SIPForum-discussion] sip uri format with the +sign

Thu Jan 5 09:43:29 UTC 2012

Hi John,

As you wrote in point A below. It is impractical to adopt these kind of
formats as they come with operational overhead. From my experience they
introduce human errors let alone complexity/scaling issues. Nowdays the
bilateral model dies carriers are exchanging traffic without geographical
awareness in mind. I believe as a requirement it will fade away as a ripe
fruit.

/nikos

On 5 January 2012 11:27, John Morlidge <John.Morlidge at jtglobal.com> wrote:

> Hi Nikos,
>
> I believe that this is less to do with the SIP standard, and more to do
> with international numbering standards, specifically E.164.  -
> http://en.wikipedia.org/wiki/E.164
> The '+' indicates to the operator that the number is in international
> format, rather than just a local number format.
>
> Firstly, let's differentiate between the 'telephone number' and the
> 'dialled number'....
>
> Roughly speaking, an E.164 'telephone number' is a globally unique number
> that identifies an end point within a PSTN network. This is used to route a
> call between networks to arrive at the correct destination.
> The dialled number, however, only has national meaning -  the '+' is
> roughly equivalent to the international call prefix
> http://en.wikipedia.org/wiki/International_call_prefix - however it should
> be noted that this prefix is not standard in all countries.
>
> Therefore, in the UK, a dialled number of '01123 456789' would be seen as
> nationally significant, whilst '00 1 123 4567' would be seen as
> internationally significant as it is prefixed with 00.  However the number
> '01123 456789' received in the US would be treated as international because
> the international prefix is 011.
>
> Within an operators network, they will generally perform digit manipulation
> to normalise the dialled numbers, and will also flag the numbers with
> national or international significance within the ISUP messaging.
> Therefore, within the UK, we would generally:
>
> Receive '00' - Strip '00' - Flag as international number in ISUP (ISUP =
> legacy signalling protocol used by many operators).
> Receive '0x' - Strip '0' - Flag as national number in ISUP.
>
> However this digit manipulation would not work if we were receiving dialled
> digits from a US customer.
>
> So now we have two potential issues:
>
> A) In a SIP environment, our customers are not longer geographically
> constrained - we can't assume that the customer is UK or US etc, and
> therefore performing digit manipulations can become impractical.
> B) There is no mechanism in SIP to identify whether the SIP URI has
> national or international significance (unlike the ISUP protocol which many
> operators use).
>
> To get around this, many operators try to adopt a standard format that
> their customers should use, and generally this is in line with the E.164
> standards. Requiring the '+' prefix allows the operator to know that this
> should be treated as an international number without performing any digit
> manipulations, or making assumptions about the format that the customer is
> sending.
>
> Thanks,
>
> John.
>
>
>
>
>
>
>
>
> From:   Nikos Leontsinis <leontsinis at gmail.com>
> To:
> Cc:     discussion at sipforum.org
> Date:   04/01/2012 18:02
> Subject:        Re: [SIPForum-discussion] sip uri format with the +sign
> Sent by:        discussion-bounces at sipforum.org
>
>
>
> I see that there are many carriers having adopted the sip uri with the + in
> front
>
>
> example:
>
>
> sip:+1-212-555-1212:1234 at gateway.com;user=phone
>
>
> This is not mandatory looking at the rfc 3261 is there any motivation
> behind this decision?
>
>
>
>
>
> /nikos_______________________________________________
> This is the SIP Forum discussion mailing list
> TO UNSUBSCRIBE, or edit your delivery options, please visit
> http://sipforum.org/mailman/listinfo/discussion
> Post to the list at discussion at sipforum.org
>
>
>
>
>
>
> This email and any attachments are confidential and may also be
> privileged. If you are not the addressee, do not disclose, copy, circulate
> or in any other way use or rely on the information contained in this email
> or any attachments. If received in error, notify the sender immediately and
> delete this email and any attachments from your system. Emails cannot be
> guaranteed to be secure or error free as the message and any attachments
> could be intercepted, corrupted, lost, delayed, incomplete or amended. JT
> Group Limited and its subsidiaries do not accept liability for damage
> caused by this email or any attachments and may monitor email traffic.
> JT Group Limited is incorporated in Jersey with limited liability under
> company number 84230 and has its registered office at No.1 The Forum,
> Grenville Street, St Helier, JE4 8PB.
> JT is the brand name of Jersey Telecom Limited a company incorporated in
> Jersey with limited liability under company number 83487 and has its
> registered office at No.1 The Forum, Grenville Street, St Helier, JE4 8PB.
> JT Global is also a trading brand of Jersey Telecom Limited.
> Wave Telecom Limited is incorporated in Guernsey with limited liability
> under company number 39971 and has its registered office at Suite 7,
> Havilland Street, St Peter Port, GY1 2QE.
> Wave Data Services Limited is incorporated in Guernsey with limited
> liability under company number 47458 and has its registered office at Suite
> 7,Havilland Street, St Peter Port, GY1 2QE and is a subsidiary of Wave
> Telecom Limited.
> Jersey Telecom (UK) Limited is incorporated in England with limited
> liability under company number 7476338 and has its registered office at 51
> Eastcheap, London, EC3M 1JP
> e.Kit.com Inc is a subsidiary of Jersey Telecom (UK) Limited and is
> registered in Boston, United States of America, with company number
> 770509280
>

-- 
Nikos Leontsinis
GSM: +306974477561
office:2103301193
ICQ Number:  201-100-938
msn: leontsinis at gmail.com
skype: leontsinis2
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sipforum.org/pipermail/discussion/attachments/20120105/aeebf426/attachment-0002.html>