Is the MSISDN stored in the VLR?

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Peter Simonsen - 30 Jan 2007 20:55 GMT

Does anyone know if the MSISDN is stored in the VLR?

I'm asking because I want to know if you can get a list from the VLR
with all the MSISDN's connected to that VLR.

I'm confused because I have found information about both cases -
stored and not stored.

According to an article in Wikipedia, the MSISDN is stored in the VLR
(http://en.wikipedia.org/wiki/GSM_core_network)

According to a report (Use of text messaging in public safety alerts)
by the Finnish Communications Regulatory Authority it is not possible
to harvest all the MSISDN's from the VLR. (www.ficora.fi/attachments/
englanti/1156489131089/Files/CurrentFile/WGReport072005.pdf, page 8)

So what should I believe?

Is it specified by ETSI/3GPP?

/Peter

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Peter Simonsen - 30 Jan 2007 22:06 GMT

Additional question: Where can the operator see the MSISDN of a
roamer? Is it also stored in the VLR (if that is the case for the
operator's own customers)?

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John Henderson - 01 Feb 2007 06:00 GMT

> Does anyone know if the MSISDN is stored in the VLR?
>
[quoted text clipped - 15 lines]
>
> So what should I believe?

That Finnish document (WGReport072005.pdf - "USE OF TEXT
MESSAGING IN PUBLIC SAFETY ALERTS") makes very interesting
reading.

I don't know the answer to your questions. Both documents agree
that the IMSI is stored. The following might add to the
confusion:

GSM 03.02, clause 3.2 discusses the VLR. It says

"the following elements are included:
- the International Mobile Subscriber Identity (IMSI);
- the Mobile Station International ISDN number (MSISDN);".

But note that an IMSI may be associated with more than one
MSISDN. For example, an IMSI capable of receiving data calls
must have separate MSISDNs for voice and data calls. And if I
recall correctly, some carriers offer (at a price) a second
voice MSISDN for an IMSI (effectively, line 1 and line 2). One
of these will be the primary MSISDN, and I don't know how a
multi-MSISDN implementation affects the ability to SMS the
device carring the SIM (whether any MSISDN associated with it
can be used).

Don't be surprised if the whole thing is more complex than would
seem necessary on a cursory glance.

John

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