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diff --git a/manuals/OsmoNITB/chapters/net.adoc b/manuals/OsmoNITB/chapters/net.adoc new file mode 100644 index 000000000..455e1a6ab --- /dev/null +++ b/manuals/OsmoNITB/chapters/net.adoc @@ -0,0 +1,139 @@ +[[net]] +== OsmoNITB Core Network Subsystem + +The OsmoNITB Core Network is a minimalistic implementation of the +classic MSC/VLR/HLR/AUC/SMSC components. None of the standardized core +network protocols (such as SCCP/TCAP/MAP) are used, interfaces between +VLR and HLR are simple function calls inside the same software package. + +OsmoNITB can thus provide autonomous voice and SMS services to its +coverage area, but it cannot provide roaming interfaces to classic GSM +operators. To support this configuration, it is suggested to use the +OsmoBSC variant of OpenBSC and interface it with a conventional MSC +using A-over-IP protocol. + +If you have classic GSM network/operator background, many of the +concepts used in OsmoNITB will appear foreign to you, as they are very +unlike the conventional GSM networks that you have worked with. + + +=== Configuring the Core Network + +Like everything else, the core network related parameters are configured +using the VTY. The respective parameters are underneath the +`network` config node. + +You can get to that node by issuing the following commands: + +.Entering the config network node +---- +OpenBSC> enable +OpenBSC# configure terminal +OpenBSC(config)# network +OpenBSC(config-net)# +---- + +A full reference to them can be found in the _OsmoNITB VTY reference +manual_ <<vty-ref-osmonitb>>. This section will only introduce the most +commonly used settings in detail. + +[TIP] +==== +You can always use the `list` VTY command to get a list of all possible +commands at the current node. +==== + + +=== Configuring the MCC/MNC + +The key identities of every GSM PLMN is the MCC and MNC. They are +identical over the entire network. In most cases, the MCC/MNC will be +allocated to the operator by the respective local regulatory authority. +For example, to set the MCC/MNC of 262-89, you may enter: + +.Configuring the MCC/MNC +---- +OpenBSC(config-net)# network country code 262 +OpenBSC(config-net)# mobile network code 89 +---- + + +=== Configuring MM INFO + +The __MM INFO__ procedure can be used after a successful __LOCATION +UPDATE__ in order to transmit the human-readable network name as well as +local time zone information to the MS. + +By default, MM INFO is not active. You can activate it, and set its +configuration using the VTY. An example is provided below. + +.Configuring MM INFO +---- +OpenBSC(config-net)# mm info 1 +OpenBSC(config-net)# short name OpenBSC +OpenBSC(config-net)# long name OpenBSC +---- + +[NOTE] +==== +Not all phone support the MM INFO procedure. Unless they already are +factory-programmed to contain the name for your MCC/MNC, then they will +likely only provide a numeric display of the network name, such as +__262-89__ or with the country code transformed into a letter, such as +__D 89__. +==== + +The time information transmitted is determined by the local system time +of the operating system on which OsmoNITB is running. As BTSs attached +to one OsmoNITB can reside in different time zones, it is possible to +use the `timezone` command at each BTS node to set different time +zone offsets in hours and quarter hours. + + +=== Setting the NECI bit + +NECI (New Establishment Cause Indication) is an optional change of the +definition for establishment cause in the RACH burst. Among other +things, in a network with NECI, a MS can explicitly indicate its TCH/H +capability while asking for a dedicated radio channel. + +It is strongly recommended to use NECI. You can do so by issuing the following command: +.Enabling NECI +---- +OpenBSC(config-net)# neci 1 +---- + + +=== Configuring Handover + +As opposed to cell re-selection in idle mode, handover refers to the +explicit transfer of a MS dedicated channel from one radio channel to +another. This typically happens due to a MS moving from one cell to +another while in an active call. + +OsmoNITB has a number of hand-over related parameters by which the +hand-over algorithm can be tuned. Logically, those settings are settings +of the BSC component, but for historic reasons, they are also configured +under the __network__ VTY node. + +.Configuring Handover +---- +OpenBSC(config-net)# handover 1 +OpenBSC(config-net)# handover window rxlev averaging 10 +OpenBSC(config-net)# handover window rxqual averaging 1 +OpenBSC(config-net)# handover window rxlev neighbor averaging 10 +OpenBSC(config-net)# handover power budget interval 6 +OpenBSC(config-net)# handover power budget hysteresis 3 +OpenBSC(config-net)# handover maximum distance 9999 +---- + +[NOTE] +==== +If you are receiving the following error message: +---- +OpenBSC(config-net)# handover 1 +% Cannot enable handover unless RTP Proxy mode is enabled by using the -P command line option +---- +then you should do as indicated and make sure to start your `osmo-nitb` process using +the `-P` command line option. +==== |