Telecoms Acronyms (CAMEL IN) Flashcards
Recall acronyms from the CAMEL Intelligent Network Book
MSC
Mobile Switching Center
is the core switching entity in the network. Users of the GSM network are registered
with an MSC; all calls to and from the user are controlled by the MSC. A GSM network has
one or more MSCs, geographically distributed.
MSC - Mobile Switching Center
VLR
Visitor Location Register
contains subscriber data for subscribers registered in an MSC. Every MSC contains a ___. Although MSC and ___ are individually addressable, they are always contained in one integrated node.
(VLR) Visitor Location Register
GMSC
Gateway MSC
is the switching entity that controls mobile terminating calls. When a call is established towards a GSM subscriber, a ___ contacts the HLR of that subscriber, to obtain the address of the MSC where that subscriber is currently registered. That MSC address is used to route the call to that subscriber
(GMSC) Gateway MSC
HLR
Home Location Register
is the database that contains a subscription record for each subscriber of the network. A GSM subscriber is normally associated with one particular ____. The ____ is responsible for the sending of subscription data to the VLR (during registration) or GMSC (during mobile terminating call handling).
(HLR) Home Location Register
CN
Core Network
consists of, amongst other things, MSC(s), GMSC(s) and HLR(s). These entities are the main components for call handling and subscriber management. Other main entities in the ___ are the equipment identification register (EIR) and authentication centre
(AUC). CAMEL has no interaction with the EIR and AUC; hence EIR and AUC are not further
discussed.
(CN) Core Network
BSS
Base Station System
is composed of one or more base station controllers (BSC) and one or more base transceiver stations (BTS). The BTS contains one or more transceivers (TRX). The TRX is responsible for radio signal transmission and reception. BTS and BSC are connected through the Abis interface. The ___ is connected to the MSC through the A interface.
(BSS) Base Station System
MS
Mobile Station
is the GSM handset.
(MS) Mobile Station
PLMN
Public Land Mobile Network
TDMA
Time Division Multiple Access
CDMA
Code Division Multiple Access
HPLMN
Home PLMN
the ___ is the GSM network that a GSM user is a subscriber of. That implies that GSM user’s subscription data resides in the HLR in that PLMN. The HLR may transfer the subscription data to a VLR (during registration in a PLMN) or a GMSC (during mobile terminating call handling). The HPLMN may also contain various service nodes, such as
a short message service centre (SMSC), service control point (SCP), etc.
(HPLMN) Home PLMN
VPLMN
Visited PLMN
the ____ is the GSM network where a subscriber is currently registered. The subscriber may be registered in her HPLMN or in another PLMN. In the latter case, the subscriber is outbound roaming (from HPLMN’s perspective) and inbound roaming
(from ___ ’s perspective). When the subscriber is currently registered in her HPLMN, then the HPLMN is at the same time ___.
(VPLMN) Visited PLMN
IPLMN
Interrogating PLMN
the ___is the PLMN containing the GMSC that handles mobile terminating (MT) calls. MT calls are always handled by a GMSC in the PLMN, regardless of the origin of the call. For most operators, MT call handling is done by a GMSC in the HPLMN; in that case, the HPLMN is at the same time ___. This implies that calls destined for a GSM
subscriber are always routed to the HPLMN of that GSM subscriber. Once the call has arrived in the HPLMN, the HPLMN acts as ___. MT call handling will be described in more detail in subsequent sections. When basic optimal routing (BOR) is applied, the ___is not the same PLMN as the HPLMN.
(IPLMN) Interrogating PLMN
The user of a GSM network is referred to as the
Served subscribe
the MSC that is handling the call is the serving MSC for this call; the calling subscriber is the served subscriber;
Mobile originated call
the GMSC that is handling the call is the serving GMSC for this call; the called subscriber is the served subscriber.
Mobile terminated call
The connections to the various entities are known as
Reference Points
the connection between MSC and BSC
“A” Interface
the connection between BSC and BTS
Abis Interface
the connection between MSC and HLR
“D” Interface
the radio connection between MS and BTS.
Um Interface
MAP
Mobile Application Part
is used for call control, subscriber registration, short message service, etc.; ___ is used over many of the GSM network interfaces
(MAP) Mobile Application Part
BSSAP
Base Station System Application Part
used over the A interface
Base Station System Application Part (BSSAP)
is used between MS and MSC; DTAP is carried over the Abis and the A interface.
(DTAP) Direct Transfer Application Part
ISUP
ISDN user part
is the protocol for establishing and releasing circuit switched calls. ___ s also used in landline Integrated Services Digital Network (ISDN). A circuit is the data channel that is established between two users in the network. Within ISDN, the data channel
is generally a 64 kbit/s channel. The circuit is used for the transfer of the encoded speech or other data.
(ISUP) ISDN user part
refers to the exchange of information for call set up
Signalling
refers to the data that is transferred within a call, i.e. voice, video, fax etc.
Payload
this is the GSM terminal, excluding the SIM card;
mobile equipment (ME)
SIM
Subscriber Identification Module
this is the chip embedded in the ___ that identifies a subscriber of a GSM network; the ___ is embedded in the ___. When the ___ card is inserted in the ME, the subscriber may register with a GSM network. The ME is now effectively personalized for this GSM subscriber;
(SIM) Subscriber Identification Module
