| Harald Welte | d41b7c7 | 2019-06-13 09:41:58 +0200 | [diff] [blame] | 1 | [[smscb]] |
| 2 | == SMSCB (Cell Broadcast) |
| 3 | |
| 4 | OsmoBSC supports SMS Cell Broadcast (SMSCB) services (CBS). This |
| 5 | includes the CBSP protocol to interact with a CBC (Cell Broadcast |
| 6 | Centre) such as OsmoCBC, as well as the scheduling of SMSCB messages on |
| 7 | both the BASIC and EXTENDED CBCH and transmission of related RSL |
| 8 | messages to the attached BTS. |
| 9 | |
| 10 | More high-level information can be found at |
| 11 | https://en.wikipedia.org/wiki/Cell_Broadcast and the related |
| 12 | specification is <<3gpp-ts-23-041>>. |
| 13 | |
| 14 | In order to use SMSCB with OsmoBSC, you will need to |
| 15 | |
| 16 | * Configure the CBSP server and/or client |
| 17 | * Use a channel combination including a CBCH on the BTSs |
| 18 | |
| 19 | === Enabling a CBCH channel combination |
| 20 | |
| 21 | On the Um interface, SMSCB are transmitted via the CBCH (Cell Broadcast |
| 22 | Channel). The CBCH is a separate downlink-only logical channel which |
| 23 | must be activated on any of the BTSs requiring CBSP support. |
| 24 | |
| 25 | The channel combination is configured in the `timeslot` node of each TRX. |
| 26 | |
| 27 | The two `phys_chan_config` supporting CBCH are `CCCH+SDCCH4+CBCH` and |
| 28 | `SDCCH/8+CBCH`. Please note that the CBCH steals one of the SDCCH, so |
| 29 | a SDCCH/4 will only have three remaining SDCCH, and a SDCCH/8 will |
| 30 | have only seven remaining SDCCH. |
| 31 | |
| 32 | === Configuring the CBSP connection |
| 33 | |
| 34 | CBSP is the protocol between BSC and CBC. It operates over TCP. |
| 35 | |
| 36 | According to 3GPP TS 48.049, a BSC typically operates as a TCP server, |
| 37 | and the CBC connects as TCP client. This would require the CBC to have |
| 38 | out-of-band knowledge of all the BSCs in the network (and their IP |
| 39 | addresses). |
| 40 | |
| 41 | In order to comply with the specifications, OsmoBSC supports this mode |
| 42 | of operation as CBSP TCP server. However, to make network operation and |
| 43 | configuration more simple, it also can operate in TCP client mode, |
| 44 | connecting to the CBC. This way the all the BSCs need to know is the CBC IP |
| 45 | address, but not vice-versa. |
| 46 | |
| 47 | The BSC can operate both CBSP TCP server and CBSP TCP client mode in |
| 48 | parallel. |
| 49 | |
| 50 | The CBC related configuration of OsmoBSC can be found in the `cbc` configuration |
| 51 | node of the VTY interface. |
| 52 | |
| 53 | .Example: Configure CBSP TCP client to connect to CBC at 1.2.3.4:48049 |
| 54 | ---- |
| 55 | OsmoBSC> enable |
| 56 | OsmoBSC# configure terminal |
| 57 | OsmoBSC(config)# cbc |
| 58 | OsmoBSC(config-cbc)# remote-ip 1.2.3.4 |
| 59 | OsmoBSC(config-cbc)# remote-port 48049 |
| 60 | OsmoBSC(config-cbc)# end |
| 61 | ---- |
| 62 | |
| 63 | .Example: Disable CBSP TCP client |
| 64 | ---- |
| 65 | OsmoBSC> enable |
| 66 | OsmoBSC# configure terminal |
| 67 | OsmoBSC(config)# cbc |
| 68 | OsmoBSC(config-cbc)# no remote-ip |
| 69 | OsmoBSC(config-cbc)# end |
| 70 | ---- |
| 71 | |
| 72 | .Example: Configure CBSP TCP server to listen for CBC at 127.0.0.2:9999 |
| 73 | ---- |
| 74 | OsmoBSC> enable |
| 75 | OsmoBSC# configure terminal |
| 76 | OsmoBSC(config)# cbc |
| 77 | OsmoBSC(config-cbc)# listen-ip 127.0.0.2 |
| 78 | OsmoBSC(config-cbc)# listen-port 9999 |
| 79 | OsmoBSC(config-cbc)# end |
| 80 | ---- |
| 81 | |
| 82 | For more details on the available configuration commands, please check the OsmoBSC VTY Reference. |