Section: Annex N (normative): Ranking of reject causes for Location Registration (MM and GMM) in a shared network
Content: This annex describes how the reject cause is determined: - for a network sharing non-supporting MS in a shared network with multi-operator core network (MOCN) configuration; or - for any MS in a multi-operator core network (MOCN) with common GERAN, when a location registration request from the MS is redirected among CN operators via the shared RAN (see 3GPP TS 23.251[ Network sharing; Architecture and functional description ]  [109]) and is rejected by all core networks. In the following, the term 'location registration' is used for location area updating, GPRS attach, combined GPRS attach, routing area updating, and combined routing area updating. i) If the location registration request was either: 1) accepted; 2) rejected with a reject cause different from #11, #12, #13, #14, #15, #17, and #25; or 3) rejected with a reject cause #17 when the MSC or the SGSN received an error not indicating "system failure", "data missing" or "unexpected data value" from the HLR (see 3GPP TS 29.002[ Mobile Application Part (MAP) specification ]  [37] and 3GPP TS 29.010[ Information element mapping between Mobile Station - Base Station System (MS - BSS) and Base Station System - Mobile-services Switching Centre (BSS - MSC); Signalling Procedures and the Mobile Application Part (MAP) ]  [152]), then one of the following actions is taken: - in UTRAN Iu mode, the MSC or SGSN shall include the redirection completed information element in the RANAP DIRECT TRANSFER message transmitting the location registration accept message or location registration reject message to the RNC. According to 3GPP TS 25.413[ UTRAN Iu interface Radio Access Network Application Part (RANAP) signalling ]  [19c], the RNC will then forward the location registration accept message or the location registration reject message to the MS. - in A/Gb mode, the shall use DTAP message and SGSN shall use BSSGP DL-UNIDATA message to carry the location registration accept message or location registration reject message to the . According to 3GPP TS 48.008[ None ]  [85] and 3GPP TS 48.018[ None ]  [86], the will then forward the location registration accept message or location registration reject message to the MS. ii) If the location registration request was either: 1) rejected with one of the reject causes #11, #12, #13, #14, #15, and #25; or 2) rejected with a reject cause #17 when the MSC or the SGSN received an error indicating "system failure", "data missing" or "unexpected data value" from the HLR (see 3GPP TS 29.002[ Mobile Application Part (MAP) specification ]  [37] and 3GPP TS 29.010[ Information element mapping between Mobile Station - Base Station System (MS - BSS) and Base Station System - Mobile-services Switching Centre (BSS - MSC); Signalling Procedures and the Mobile Application Part (MAP) ]  [152]), then one of the following actions is taken: - in UTRAN Iu mode, the MSC or SGSN shall include a redirection indication in the RANAP DIRECT TRANSFER message transmitting the location registration reject message to the RNC. According to 3GPP TS 25.413[ UTRAN Iu interface Radio Access Network Application Part (RANAP) signalling ]  [19c], the RNC will then initiate the redirection procedure towards the next CN operator and treat the response from the core network according to (i) and (ii). - in A/Gb mode, the shall use BSSMAP Reroute Command message and SGSN shall use BSSGP DL-UNIDATA message to transmit the location registration reject message to the with a redirection indication. According to 3GPP TS 48.008[ None ]  [85] and 3GPP TS 48.018[ None ]  [86], the will then initiate the redirection procedure towards the next CN operator and treat the response from the core network according to (i), (ii) and (iii). iii) If the location registration request was rejected including a redirection indication and with one of the reject causes #11, #12, #13, #14, #15, #17, and #25 by all CN operators taking part in a shared network, the RNC for UTRAN Iu mode or the for A/Gb mode shall determine the reject cause with the highest rank from the received reject causes and send a location registration reject message containing this reject cause to the MS. The ranking of the reject causes, from the lowest rank to the highest rank, is given by: #11 < #12 < #13 < #14 < #15 < #25 < #17. iv) If the location registration request was rejected with one of the reject causes #11, #12, #13, #14, and #15 by all CN operators taking part in a shared network in a specific location area, but there is at least one additional CN operator taking part in a shared network in another location area of the shared network defined by the same common PLMN identity, the RNC for UTRAN Iu mode or the for A/Gb mode shall send a location registration reject message with the reject cause #15 to the MS.