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diff --git a/OsmoBTS/chapters/architecture.adoc b/OsmoBTS/chapters/architecture.adoc deleted file mode 100644 index a0e66cd..0000000 --- a/OsmoBTS/chapters/architecture.adoc +++ /dev/null @@ -1,120 +0,0 @@ -== OsmoBTS software architecture - -=== OsmoBTS PHY interface abstraction - -The OsmoBTS PHY interface serves as an internal abstraction layer -between given PHY hardware (as provided by the bts_model) and the actual -logical transceivers (TRXs) of a BTS inside the OsmoBTS code base. - - -==== PHY link - -A PHY link is a physical connection / link towards a given PHY. This -might be, for example, - -* a set of file descriptors to device nodes in the /dev/ directory - (sysmobts, litecell15) -* a packet socket for sending raw Ethernet frames to an OCTPHY -* a set of UDP sockets for interacting with OsmoTRX - -Each PHY interface has a set of attribute/parameters and a list of 1 to -n PHY instances. - -PHY links are numbered 0..n globally inside OsmoBTS. - -Each PHY link is configured via the VTY using its individual top-level -vty node. Given the different bts-model / phy specific properties, the -VTY configuration options (if any) of the PHY instance differ between -BTS models. - -The PHY links and instances must be configured above the BTS/TRX nodes -in the configuration file. If the file is saved via the VTY, the code -automatically ensures this. - - -==== PHY instance - -A PHY instance is an instance of a PHY, accessed via a PHY link. - -In the case of osmo-bts-sysmo and osmo-bts-trx, there is only one -instance in every PHY link. This is due to the fact that the API inside -that PHY link does not permit for distinguishing multiple different -logical TRXs. - -Other PHY implementations like the OCTPHY however do support addressing -multiple PHY instances via a single PHY link. - -PHY instances are numbered 0..n inside each PHY link. - -Each PHY instance is configured via the VTY as a separate node beneath each -PHY link. Given the different bts-model / phy specific properties, the -VTY configuration options (if any) of the PHY instance differ between -BTS models. - - -==== Mapping PHY instances to TRXs - -Each TRX node in the VTY must use the 'phy N instance M' command in -order to specify which PHY instance is allocated to this specific TRX. - -=== Internal control flow - -==== start-up / sequencing during OsmoBTS start - -.Control flow at OsmoBTS start-up procedure -[options="header",cols="10%,35%,55%"] -|=== -| section | function | description -| bts-specific | main() | Entering main() from glibc -| common | bts_main() | initialization of talloc contexts -| common | bts_log_init() | initialization of logging -| common | handle_options() | common option parsing -| bts-specific | bts_model_handle_options() | model-specific option parsing -| common | gsm_bts_alloc() | allocation of BTS/TRX/TS data structures -| common | vty_init() | Initialziation of VTY core, libosmo-abis and osmo-bts VTY -| common | main() | Setting of scheduler RR priority (if configured) -| common | main() | Initialization of GSMTAP (if configured) -| common | bts_init() | configuration of defaults in bts/trx/s object -| bts-specific | bts_model_init | ? -| common | abis_init() | Initialization of libosmo-abis -| common | vty_read_config_file() | Reading of configuration file -| bts-specific | bts_model_phy_link_set_defaults() | Called for every PHY link created -| bts-specific | bts_model_phy_instance_set_defaults() | Called for every PHY Instance created -| common | bts_controlif_setup() | Initialization of Control Interface -| bts-specific | bts_model_ctrl_cmds_install() | Install model-specific control interface commands -| common | telnet_init() | Initialization of telnet interface -| common | pcu_sock_init() | Initialization of PCU socket -| common | main() | Installation of signal handlers -| common | abis_open() | Start of the A-bis connection to BSC -| common | phy_links_open() | Iterate over list of configured PHY links -| bts-specific | bts_model_phy_link_open() | Open each of the configured PHY links -| common | write_pid_file() | Generate the pid file -| common | osmo_daemonize() | Fork as daemon in background (if configured) -| common | bts_main() | Run main loop until global variable quit >= 2 -|=== - - -==== At time of OML establishment - -.Control flow at time of OML establishment -[options="header",cols="10%,35%,55%"] -|=== -| section | function | description -| bts-specific | bts_model_oml_estab() | Called by core once OML link is established -| bts-specific | bts_model_check_oml() | called each time OML sets some attributes on a MO, checks if attributes are valid -| bts-specific | bts_model_apply_oml() | called each time OML sets some attributes on a MO, stores attribute contents in data structures -| bts-specific | bts_model_opstart() | for NM_OC_BTS, NM_OC_SITE_MANAGER, NM_OC_GPRS_NSE, NM_OC_GPRS_CELL, NMO_OC_GPRS_NSVC -| bts-specific | bts_model_opstart() | for NM_OC_RADIO_CARRIER for each trx -| bts-specific | bts_model_opstart() | for NM_OC_BASEB_TRANSC for each trx -| bts-specific | bts_model_opstart() | for NM_OC_CHANNEL for each timeslot on each trx -| bts-specific | bts_model_change_power() | change transmit power for each trx (power ramp-up/ramp-down) -|=== - -==== At time of RSL connection loss - -.Control flow at time of RSL connection loss -[options="header",cols="10%,35%,55%"] -|=== -| section | function | description -| bts-specific | bts_model_abis_close() | called when either one of the RSL links or the OML link are down -|=== |