Talk:Network switching subsystem

A lot of the technical terms and acronyms on this page link to redirects that just bounce people back here. It would be best if those terms were explained on this page. Also, the language here is very acronym-heavy and very abstract. It would be good if terms were spelled out, non-technical vocabulary used to explain technical terms. Also, it's important to talk in concrete terms, about what sort of hardware is actually typically used to serve as a given TLA. The article currently speaks largely in abstract terms more appropriate to a hardware-agnostic specification. -- Beland 23:11, 27 Dec 2004 (UTC)


 * I agree with your comments. I will attempt to clarify some of the text.  It is a complex subject though - I think it is best served by splitting into a "descriptions" article which desribes what all the elements do and a "how it works" article which goes into more detail (heavily cross referenced to make editing easier.  Can you comment on the page GSM services which was split off from the main GSM page to try and address exactly this kind of issue.  Is that the right level for non-technical users?? ChrisUK 23:25, 27 Dec 2004 (UTC)


 * (Comments made there. -- User: 11:16, 29 Dec 2004 (UTC))

OK, coming back here, I realize now that this article is the "parts list" or glossary for the explanation in GSM services. Things could be much improved if the various articles at play were re-titled and cross-referenced more tightly. Given my suggestions on Talk:GSM services, I'm not sure what articles might be merged with what else. Assuming no mergers take place, I think what you'd want to do is leave social/political/economic context at Global System for Mobile Communications, re-title GSM services as How GSM works, and re-title GSM core network as "GSM network elements" or "GSM glossary" or something. The intros of the other two pages should clearly point readers interested in How GSM works to that article. -- Beland 11:15, 29 Dec 2004 (UTC)

Technical Error in HLR section?
I noticed that in the section of this article detailing the function of the HLR, the text seems to claim that both the IMSI and the MSISDN are separately primary keys for HLR records, which is impossible by the very definition a primary key. Based on the description of the HLR and how these numbers relate to HLR records, I'm led to believe that the MSISDN is the primary key for HLR records and not the IMSI, since it is written that multiple (secondary) MSISDNs may be related to a SIM (and, therefore, an IMSI). Or, alternatively, it occurs to me that the primary key might instead be the combination of these two entities, in which case this could stand to be better clarified to the reader.

Either way I'm not knowledgeable enough on the topic to make such an edit, but if someone with the appropriate knowledge could do so that would be great. 72.235.162.95 13:36, 12 August 2007 (UTC)

The article is changed, but I think that together with this change a bit of information intended to be provided by original version has been lost. I think that problem is that "primary key" is typical database term, while we speak here about values by which we can find HLR record fast. In fact, when you e.g. change SIM card because old has been destroyed, you get new IMSI, but your old MSISDN is left intact. Because HLR is not defined in terms of (relational) DBMS language, then it is possible that actual implementation of HLR will not have anything resembling "primary key" inside.

80.55.244.74 (talk) 23:46, 21 December 2010 (UTC)

"To do list" for making the article less technical for readers

 * The AuC for 3G needs to be described accurately (or perhaps open another page as this one is starting to get long)
 * rewrite sections describing elements split into description/other elements it connects to and procedures. This way non technical readers can skip over the last two sections if they wish
 * Could use a diagram or two - there is one on the main GSM page but I think something clearer is required and relevant to just the core network ChrisUK 09:37, 28 Dec 2004 (UTC)
 * An architecture/context section is needed just after the intro and just before the HLR section to tie all the elements together (this is where a diagram should go). I'm working on one this week, but anyone else feel free ChrisUK 23:24, 28 Dec 2004 (UTC)

VLR issue
The Visitor Location Register (VLR) should not use the plural 'Visitors' as on this page and probably elsewhere. Google for 'visitor VLR GSM' for evidence - very few sites and no glossaries use the plural.

network w/o HLR
I am fairly certain that in the case of an HLR outage, the MSC/VLR would still be able to process calls for MSs that did not travel outside of that LA. Of course, if the MS went into another LA, the target MSC would require the HLR in order to update its VLR. Cacophony 02:04, 12 November 2005 (UTC)


 * wow - long term bump; if an HLR goes down, then the sub homed on that HLR would still be able to MAKE calls, as long as (s)he stays on their VMSC;  however, they wouldn't be able to receive calls, since the SRI from the GMSC (either PSTN gateway, inter-PLMN, or serving MSC of A party) would fail.  Same goes for SMS.  This is also limited to the network dependant VLR purge time scale, and periodic location updates.  Trust me on this, HLR outages are very very bad... I've lived through a few, as the HLR vendor to a pretty major operator - we made the national news, when it went down for 12 hours, courtesy of a software bug :)

HLR & VLR
HLR and VLR are entities that are not unique to GSM networks. (As are many concepts on this whole page) These should be either broken out into their own network-generic pages, and/or much of this page needs to be less GSM specific. --Alexjag 23:53, 13 July 2006 (UTC)

MSS and MSCS?
The acronyms surrounding the mobile switching centre server are a bit confusing here and on the mobile switching centre page. The abbreviation provided in parentheses on this page is MSCS but the abbreviation actually used in the text here is MSS. On the mobile switching centre server page the only abbreviation used is MSS. Presumably MSS is the correct abbreviation and MSCS was just added in error, but someone should verify this and make the appropriate corrections. --Ennustaja (talk) 12:48, 1 June 2010 (UTC)