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diff --git a/OsmoBTS/abis/oml.adoc b/OsmoBTS/abis/oml.adoc new file mode 100644 index 0000000..778a084 --- /dev/null +++ b/OsmoBTS/abis/oml.adoc @@ -0,0 +1,937 @@ +== Organization & Maintenance Link (OML) + +=== List of Messages + +The following tables list the OML messages used by OsmoBTS, grouped by their +level of compliance with 3GPP TS 12.21. + +==== Messages Compliant With TS 12.21 + +Specific limitations apply, see the linked sections. + +.Messages compliant with TS 12.21 +[options="header",cols="10%,10%,20%,35%,5%,20%"] +|=== +| TS 12.21 § | type code (hex) | This document § | Message | <-/-> | Received/Sent by OsmoBTS +6+<| *SW Download Management Messages:* +| 8.3.7 | 0x10 | <<sw_act_rep>> | SW Activated Report | -> | Sent +6+<| *Air Interface Management Messages:* +.3+.| 8.6.1 | 0x41 .3+.| <<set_bts_attr>> | Set BTS Attributes | <- | Received + | 0x42 | Set BTS Attributes Ack | -> | Sent + | 0x43 | Set BTS Attributes Nack | -> | Sent +.3+.| 8.6.2 | 0x44 .3+.| <<set_radio_attr>> | Set Radio Carrier Attributes | <- | Received + | 0x45 | Set Radio Carrier Attributes Ack | -> | Sent + | 0x46 | Set Radio Carrier Attributes Nack | -> | Sent +.3+.| 8.6.3 | 0x47 .3+.| <<set_chan_attr>> | Set Channel Attributes | <- | Received + | 0x48 | Set Channel Attributes Ack | -> | Sent + | 0x49 | Set Channel Attributes Nack | -> | Sent +6+<| *State Management and Event Report Messages:* + | 8.8.1 | 0x61 | <<state_changed_rep>> | State Changed Event Report | -> | Sent +.3+.| 8.8.5 | 0x69 .3+.| <<chg_adm_state>> | Change Administrative State | <- | Received + | 0x6A | Change Administrative State Ack | -> | Sent + | 0x6B | Change Administrative State Nack | -> | Sent +6+<| *Equipment Management Messages:* +.3+.| 8.9.2 | 0x74 .3+.| <<opstart>> | Opstart | <- | Received + | 0x75 | Opstart Ack | -> | Sent + | 0x76 | Opstart Nack | -> | Sent +|=== + + +==== Messages Specific to OsmoBTS + +.Messages specific to OsmoBTS, not found in 3GPP TS 12.21 +[options="header"] +[options="header",cols="20%,55%,5%,20%"] +|=== +| This document § | Message | <-/-> | Received/Sent by OsmoBTS +| <<ipacc_set_attr>> | Set Attribute | <- | Received +|=== + + +==== Messages Not Implemented by OsmoBTS +.3GPP TS 12.21 messages not implemented by OsmoBTS +[options="header",cols="10%,10%,80%"] +|=== +| TS 12.21 § | type code (hex) | Message +3+<| *SW Download Management Messages:* +.3+.| 8.3.1 | 0x01 | Load Data Initiate + | 0x02 | Load Data Initiate Ack + | 0x03 | Load Data Initiate Nack +.2+.| 8.3.2 | 0x04 | Load Data Segment + | 0x05 | Load Data Segment Ack + | 8.3.3 | 0x06 | Load Data Abort +.3+.| 8.3.4 | 0x07 | Load Data End + | 0x08 | Load Data End Ack + | 0x09 | Load Data End Nack +.3+.| 8.3.5 | 0x0A | SW Activate Request + | 0x0B | SW Activate Request Ack + | 0x0C | SW Activate Request Nack +.3+.| 8.3.6 | 0x0D | Activate SW + | 0x0E | Activate SW Ack + | 0x0F | Activate SW Nack +3+<| *A-bis Interface Management Messages:* +.3+.| 8.4.1 | 0x21 | Establish TEI + | 0x22 | Establish TEI Ack + | 0x23 | Establish TEI Nack +.3+.| 8.4.2 | 0x24 | Connect Terrestrial Signalling + | 0x25 | Connect Terrestrial Signalling Ack + | 0x26 | Connect Terrestrial Signalling Nack +.3+.| 8.4.3 | 0x27 | Disconnect Terrestrial Signalling + | 0x28 | Disconnect Terrestrial Signalling Ack + | 0x29 | Disconnect Terrestrial Signalling Nack +.3+.| 8.4.4 | 0x2A | Connect Terrestrial Traffic + | 0x2B | Connect Terrestrial Traffic Ack + | 0x2C | Connect Terrestrial Traffic Nack +.3+.| 8.4.5 | 0x2D | Disconnect Terrestrial Traffic + | 0x2E | Disconnect Terrestrial Traffic Ack + | 0x2F | Disconnect Terrestrial Traffic Nack +3+<| *Transmission Management Messages:* +.3+.| 8.5.1 | 0x31 | Connect Multi-Drop Link + | 0x32 | Connect Multi-Drop Link Ack + | 0x33 | Connect Multi-Drop Link Nack +.3+.| 8.5.2 | 0x34 | Disconnect Multi-Drop Link + | 0x35 | Disconnect Multi-Drop Link Ack + | 0x36 | Disconnect Multi-Drop Link Nack +3+<| *Test Management Messages:* +.3+.| 8.7.1 | 0x51 | Perform Test + | 0x52 | Perform Test Ack + | 0x53 | Perform Test Nack +.3+.| 8.7.2 | 0x54 | Test Report + | 0x55 | Send Test Report + | 0x56 | Send Test Report Ack + | 8.7.3 | 0x57 | Send Test Report Nack +.3+.| 8.7.4 | 0x58 | Stop Test + | 0x59 | Stop Test Ack + | 0x5A | Stop Test Nack +3+<| *State Management and Event Report Messages:* + | 8.8.2 | 0x62 | Failure Event Report +.3+.| 8.8.3 | 0x63 | Stop Sending Event Reports + | 0x64 | Stop Sending Event Reports Ack + | 0x65 | Stop Sending Event Reports Nack +.3+.| 8.8.4 | 0x66 | Restart Sending Event Reports + | 0x67 | Restart Sending Event Reports Ack + | 0x68 | Restart Sending Event Reports Nack +.3+.| 8.8.6 | 0x6C | Change Administrative State Request + | 0x6D | Change Administrative State Request Ack + | 0x6E | Change Administrative State Request Nack +.3+.| 8.8.7 | 0x93 | Report Outstanding Alarms + | 0x94 | Report Outstanding Alarms Ack + | 0x95 | Report Outstanding Alarms Nack +3+<| *Equipment Management Messages:* +.3+.| 8.9.1 | 0x71 | Changeover + | 0x72 | Changeover Ack + | 0x73 | Changeover Nack +.3+.| 8.9.3 | 0x87 | Reinitialize + | 0x88 | Reinitialize Ack + | 0x89 | Reinitialize Nack +.3+.| 8.9.4 | 0x77 | Set Site Outputs + | 0x78 | Set Site Outputs Ack + | 0x79 | Set Site Outputs Nack +.3+.| 8.9.5 | 0x90 | Change HW Configuration + | 0x91 | Change HW Configuration Ack + | 0x92 | Change HW Configuration Nack +3+<| *Measurement Management Messages:* + | 8.10.1 | 0x8A | Measurement Result Request + | 8.10.2 | 0x8B | Measurement Result Response + | 8.10.3 | 0x8C | Stop Measurement + | 8.10.4 | 0x8D | Start Measurement +3+<| *Other Messages:* + | 8.11.1 | 0x81 | Get Attributes + | 8.11.3 | 0x82 | Get Attribute(s) Response + | 8.11.1 | 0x83 | Get Attributes Nack +.3+.| 8.11.2 | 0x84 | Set Alarm Threshold + | 0x85 | Set Alarm Threshold Ack + | 0x86 | Set Alarm Threshold Nack +|=== + + +=== Details on Compliant OML Messages + +[[sw_act_rep]] +==== SW Activated Report + +OsmoBTS will send an _SW Activated Report_ when RF has been activated +successfully. The message is compliant with 3GPP TS 12.21 § 8.3.7. + +Upon RF activation, two _SW Activated Report_ messages will be sent, for the Object Classes + +- Radio Carrier (0x02) +- Baseband Transceiver (0x04) + +[[set_bts_attr]] +==== Set BTS Attributes + +OsmoBTS will receive a _Set BTS Attributes_ message and reply with a +corresponding ACK message on success. IE handling is fully compliant to TS +12.21, except that a change of BCCH ARFCN or BSIC while in operation is not +supported, and hence the _Starting Time_ IE is rejected. + +._Set BTS Attributes_ IEs not handled by OsmoBTS +[options="header",cols="10%,30%,60%"] +|=== +| TS 12.21 § | IE Name | Handling +| 9.4.52 | Starting Time | not supported (provokes NACK cause 0x10) +|=== + + +[[set_radio_attr]] +==== Set Radio Carrier Attributes + +This message conforms to 3GPP TS 12.21, with the following limitation, +as frequency hopping is not supported by OsmoBTS: + +._Set Radio Carrier Attributes_ IE limitations +[options="header",cols="10%,30%,60%"] +|=== +| TS 12.21 § | IE Name | Handling +| 9.4.5 | ARFCN List | ignored +|=== + + +[[set_chan_attr]] +==== Set Channel Attributes + +This message conforms to 3GPP TS 12.21, with the following limitation: OpenBTS +does not support frequency hopping, and the following 3GPP TS 12.21 IEs provoke +a NACK response when sent to OsmoBTS, as frequency hopping is not +supported: + +._Set Channel Attributes_ IE limitations +[options="header",cols="10%,30%,60%"] +|=== +| TS 12.21 § | IE Name | Handling +| 9.4.21 | HSN | not supported (provokes NACK cause 0x10) +| 9.4.27 | MAIO | not supported (provokes NACK cause 0x10) +| 9.4.52 | Starting Time | not supported (provokes NACK cause 0x10) +|=== + +[[state_changed_rep]] +==== State Changed Event Report + +This message is compliant with 3GPP TS 12.21. Exactly these IEs are sent by +OsmoBTS: + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message Type (0xf5) | 3GPP TS 12.21 9.1 | M | V | 1 +| Object Class | 3GPP TS 12.21 9.2 | M | V | 1 +| Object Instance | 3GPP TS 12.21 9.3 | M | V | 3 +| Operational State | 3GPP TS 12.21 9.4.38 | O | TV | 2 +| Availability Status | 3GPP TS 12.21 9.4.7 | O | TL16V (with length of 1) | 3 +|=== + +[[chg_adm_state]] +==== Change Administrative State + +This message is compliant with 3GPP TS 12.21 § 8.8.5. It applies to all of the +Objects Classes defined in 3GPP TS 12.21 § 9.2 as well as +<<addnl_obj_classes>>. + +[[opstart]] +==== Opstart + +This message is compliant with 3GPP TS 12.21 § 8.9.2. It applies to all of the +Objects Classes defined in 3GPP TS 12.21 § 9.2 as well as +<<addnl_obj_classes>>. + + +=== Details on OsmoBTS Specific Messages + +[[ipacc_set_attr]] +==== Set Attribute + +The message type is 0xf5. This message is sent to OsmoBTS to set +attributes on instances of managed objects of the non-standard +additional Object Classes (see <<addnl_obj_classes>>). + +The message specifics depend on the Object Class and are detailed in +<<addnl_obj_classes>>. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message Type (0xf5) | 3GPP TS 12.21 9.1 | M | V | 1 +| Object Class | 3GPP TS 12.21 9.2 | M | V | 1 +| Object Instance | 3GPP TS 12.21 9.3 | M | V | 3 +5+<| _Object Class specific IEs follow, see <<addnl_obj_classes>>..._ +|=== + + +[[addnl_obj_classes]] +=== Additional Object Classes + +In addition to 3GPP TS 12.21 Chapter 9.2, the following managed objects +are supported: + +.Additional Managed Object Classes +[options="header"] +[cols="20%,20%,60%"] +|=== +| Value | Name | Description +| 0xf0 | GPRS NSE | GPRS-NS Entity +| 0xf1 | GPRS CELL | GPRS Cell Entity +| 0xf2 | GPRS NSVC | GPRS NS Virtual Circuit +|=== + +==== GPRS-NSE Managed Object + +There is one NS Entity per BTS. It supports the *Set Attribute* message +with the following Information Elements: + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message Type | 3GPP TS 12.21 9.1 | M | V | 1 +| Object Class | 3GPP TS 12.21 9.2 | M | V | 1 +| Object Instance | 3GPP TS 12.21 9.3 | M | V | 3 +| GPRS NSEI | <<NM_ATT_IPACC_NSEI>> | O | TL16V | >= 5 +| GPRS NS Configuration | <<NM_ATT_IPACC_NS_LINK_CFG>> | O | TL16V | >= 10 +| GPRS BSSGP Configuration | <<NM_ATT_IPACC_BSSGP_CFG>> | O | TL16V | >= 14 +|=== + +==== GPRS Cell Managed Object + +There is one GPRS Cell entity per BTS. It supports the *Set Attribute* +message with the following Information Elements: + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message Type | 3GPP TS 12.21 9.1 | M | V | 1 +| Object Class | 3GPP TS 12.21 9.2 | M | V | 1 +| Object Instance | 3GPP TS 12.21 9.3 | M | V | 3 +| GPRS Routing Area Code | <<NM_ATT_IPACC_RAC>> | O | TL16V | >= 4 +| GPRS Paging Configuration | <<NM_ATT_IPACC_GPRS_PAGING_CFG>> | O | TL16V | >= 5 +| GPRS RLC Configuration | <<NM_ATT_IPACC_RLC_CFG>> | O | TL16V | >= 12 +| GPRS Coding Schemes | <<NM_ATT_IPACC_CODING_SCHEMES>> | O | TL16V | >= 5 +| GPRS RLC Configuration 2 | <<NM_ATT_IPACC_RLC_CFG_2>> | O | TL16V | >= 8 +| GPRS RLC Configuration 3 | <<NM_ATT_IPACC_RLC_CFG_3>> | O | TL16V | >= 4 +|=== + +==== GPRS NS-VC Managed Object + +There are two GPRS NS-VC instances per BTS. It supports the *Set +Attribute* message with the following Information Elements: + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message Type | 3GPP TS 12.21 9.1 | M | V | 1 +| Object Class | 3GPP TS 12.21 9.2 | M | V | 1 +| Object Instance | 3GPP TS 12.21 9.3 | M | V | 3 +| GPRS NSVCI | <<NM_ATT_IPACC_NSVCI>> | O | TL16V | >= 5 +| GPRS NS Link Configuration | <<NM_ATT_IPACC_NS_LINK_CFG>> | O | TL16V | >= 11 +|=== + + +=== Information Elements Overview + +All of the IEs handled by OsmoBTS are listed below, with limitations and +additions to TS 12.21 specified in more detail. + +==== IEs Conforming to TS 12.21 + +The following Information Elements are accepted by OsmoBTS. Not all IEs are +actually evaluated. + +.IEs conforming to TS 12.21 +[options="header",cols="5%,10%,40%,5%,40%"] +|=== +| tag (hex) | TS 12.21 § | IE name | <-/-> | Received/Sent by OsmoBTS +| 0x00 | 9.4.1 | Abis Channel | | _ignored_ +| 0x01 | 9.4.2 | Additional Info | | _ignored_ +| 0x02 | 9.4.3 | Additional Text | | _ignored_ +| 0x03 | 9.4.4 | Administrative State | <- -> | Received & Sent +| 0x04 | 9.4.5 | ARFCN List | <- | Received, with exactly 1 ARFCN: see <<NM_ATT_ARFCN_LIST>>; + ignored by _Set Radio Attribute_ message (<<set_radio_attr>>) +| 0x05 | 9.4.6 | Autonomously Report | | _ignored_ +| 0x06 | 9.4.7 | Availability Status | -> | Sent +| 0x07 | 9.4.8 | BCCH ARFCN | <- | Received +| 0x08 | 9.4.9 | BSIC | <- | Received +| 0x09 | 9.4.10 | BTS Air Timer | <- | Received +| 0x0a | 9.4.11 | CCCH Load Indication Period | <- | Received +| 0x0b | 9.4.12 | CCCH Load Threshold | <- | Received +| 0x0c | 9.4.13 | Channel Combination | <- | Received, with additional channel combinations: see <<ie_chan_comb>> +| 0x0d | 9.4.14 | Connection Failure Criterion | <- | Received, with limitations see <<ie_conn_fail_crit>> +| 0x0e | 9.4.15 | Destination | | _ignored_ +| 0x0f | 9.4.16 | Event Type | | _ignored_ +| 0x11 | 9.4.17 | File Data | | _ignored_ +| 0x12 | 9.4.18 | File Id | | _ignored_ +| 0x13 | 9.4.19 | File Version | | _ignored_ +| 0x14 | 9.4.20 | GSM Time | | _ignored_ +| 0x16 | 9.4.22 | HW Configuration | | _ignored_ +| 0x18 | 9.4.24 | Intave Parameter | <- | _ignored_ +| 0x19 | 9.4.25 | Interference level Boundaries | <- | _ignored_ +| 0x1a | 9.4.26 | List of Required Attributes | | _ignored_ +| 0x1c | 9.4.28 | Manufacturer Dependent State | | _ignored_ +| 0x1d | 9.4.29 | Manufacturer Dependent Thresholds | | _ignored_ +| 0x1e | 9.4.30 | Manufacturer Id | | _ignored_ +| 0x1f | 9.4.31 | Max Timing Advance | <- | Received +| 0x20 | 9.4.34 | Multi-drop BSC Link | | _ignored_ +| 0x21 | 9.4.35 | Multi-drop next BTS Link | | _ignored_ +| 0x22 | 9.4.36 | Nack Causes | -> | Sent +| 0x23 | 9.4.37 | Ny1 | <- | Received +| 0x24 | 9.4.38 | Operational State | -> | Sent +| 0x25 | 9.4.39 | Overload Period | <- | _ignored_ +| 0x26 | 9.4.40 | Physical Config | | _ignored_ +| 0x27 | 9.4.41 | Power Class | | _ignored_ +| 0x28 | 9.4.42 | Power Output Thresholds | | _ignored_ +| 0x29 | 9.4.43 | Probable Cause | | _ignored_ +| 0x2a | 9.4.44 | RACH Busy Threshold | <- | Received +| 0x2b | 9.4.45 | RACH Load Averaging Slots | <- | _ignored_ +| 0x2c | 9.4.46 | Radio Sub Channel | | _ignored_ +| 0x2d | 9.4.47 | RF Max Power Reduction | <- | Received +| 0x2e | 9.4.48 | Site Inputs | | _ignored_ +| 0x2f | 9.4.49 | Site Outputs | | _ignored_ +| 0x30 | 9.4.50 | Source | | _ignored_ +| 0x31 | 9.4.51 | Specific Problems | | _ignored_ +| 0x33 | 9.4.53 | T200 | <- | _ignored_ (1s on DCCH, 2s on ACCH) +| 0x34 | 9.4.54 | TEI | | _ignored_ +| 0x35 | 9.4.55 | Test Duration | | _ignored_ +| 0x36 | 9.4.56 | Test No | | _ignored_ +| 0x37 | 9.4.57 | Test Report Info | | _ignored_ +| 0x38 | 9.4.58 | VSWR Thresholds | | _ignored_ +| 0x39 | 9.4.59 | Window Size | | _ignored_ +| 0x40 | 9.4.60 | TSC | <- | Received, with limitations: see <<NM_ATT_TSC>> +| 0x41 | 9.4.61 | SW Configuration | | _ignored_ +| 0x43 | 9.4.63 | Perceived Severity | | _ignored_ +| 0x44 | 9.4.64 | Get Attribute Response Info | | _ignored_ +| 0x45 | 9.4.65 | Outstanding Alarm Sequence | | _ignored_ +| 0x46 | 9.4.66 | HW Conf Change Info | | _ignored_ +| 0x47 | 9.4.32 | Measurement Result | | _ignored_ +|=== + +==== IEs Not Conforming to TS 12.21 + +.IEs not conforming to TS 12.21 +[options="header",cols="5%,10%,30%,55%"] +|=== +| tag (hex) | TS 12.21 § | IE name | Description +| 0x15 | 9.4.21 | HSN | presence causes NACK response +| 0x17 | 9.4.23 | HW Description | _ignored_ by OsmoBTS, but coding may differ, see <<ie_hw_desc>> +| 0x1b | 9.4.27 | MAIO | presence causes NACK response +| 0x32 | 9.4.52 | Starting Time | presence causes NACK response +| 0x42 | 9.4.62 | SW Description | not supported +| 0x48 | 9.4.33 | Measurement Type | not supported +|=== + + +==== Additional Attributes and Parameters + +The following Information Elements are defined in addition to those +specified in 3GPP TS 12.21 Chapter 9.4. + +All of these additional IEs are _received_ by OsmoBTS. + +The content of these attributes is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + +.Additional IEs handled by OsmoBTS but not defined in TS 12.21 +[options="header",cols="5%,50%,45%"] +|=== +| tag (hex) | IE name | Description +| 0x80 | RSL Destination IP Address | <<NM_ATT_IPACC_DST_IP>> +| 0x81 | RSL Destination TCP Port | <<NM_ATT_IPACC_DST_IP_PORT>> +| 0x85 | RSL IPA Stream ID | <<NM_ATT_IPACC_STREAM_ID>> +| 0x9a | GPRS Routing Area Code | <<NM_ATT_IPACC_RAC>> +| 0x9c | GPRS Paging Configuration | <<NM_ATT_IPACC_GPRS_PAGING_CFG>> +| 0x9d | GPRS NSEI | <<NM_ATT_IPACC_NSEI>> +| 0x9e | GPRS BVCI | <<NM_ATT_IPACC_BVCI>> +| 0x9f | GPRS NSVCI | <<NM_ATT_IPACC_NSVCI>> +| 0xa0 | GPRS NS Configuration | <<NM_ATT_IPACC_NS_CFG>> +| 0xa1 | GPRS BSSGP Configuration | <<NM_ATT_IPACC_BSSGP_CFG>> +| 0xa2 | GPRS NS Link Configuration | <<NM_ATT_IPACC_NS_LINK_CFG>> +| 0xa3 | GPRS RLC Configuration | <<NM_ATT_IPACC_RLC_CFG>> +| 0xa8 | GPRS Coding Schemes | <<NM_ATT_IPACC_CODING_SCHEMES>> +| 0xa9 | GPRS RLC Configuration 2 | <<NM_ATT_IPACC_RLC_CFG_2>> +| 0xac | GPRS RLC Configuration 3 | <<NM_ATT_IPACC_RLC_CFG_3>> +|=== + + +=== Details on IEs + +[[ie_hw_desc]] +==== HW Description + +TS 12.21 suggests a series of 5 length-value pairs for the _HW Description_ IE. +Instead, OsmoBTS interprets it as a single TL16V. The value of this IE is +ignored by OsmoBTS, yet the coding may affect message parsing. + +[width="40%",cols="90%,10%"] +[grid="none"] +|=== +| Attribute Identifier (0x17) | 1 +| Length | 2-3 +| Ignored | N +|=== + + +[[NM_ATT_ARFCN_LIST]] +==== ARFCN List + +Since OsmoBTS does not support frequency hopping, the _ARFCN List_ must contain +exactly one ARFCN. + +[[ie_chan_comb]] +==== Additional Channel Combinations + +In addition to 3GPP TS 12.21 Chapter 9.4.13, the following channel +combinations are supported: + +.Additional Channel Combinations +[options="header"] +[cols="10%,90%"] +|=== +| Value | Description +| 0x0b | Reserved for PBCCH + PCCCH + PDTCH/F + PACCH/F + PTCCH/F +| 0x0c | Reserved for PBCCH + PDTCH/F + PACCH/F + PTCCH/F +| 0x0d | PDTCH/F + PACCH/F + PTCCH/F +| 0x80 | Reserved for Dynamic TCH/F / PDCH +| 0x81 | Reserved for Dynamic TCH/F / TCH/H +|=== + +[[ie_conn_fail_crit]] +==== Connection Fail Criterion + +3GPP TS 12.21 Chapter 9.4.14 specifies two different options for the +_Connection Failure Criterion_. OsmoBTS only implements the option +coded as 0x01, i.e. based upon uplink SACCH error rate +(RADIO_LINK_TIMEOUT). + +[[NM_ATT_TSC]] +==== TSC + +Due to limitations in the currently supported PHY implementations, +OsmoBTS supports only one global TSC for all channels on one TRX, rather +than a separate TSC for each timeslot, as expected by 3GPP TS 12.21. + + +[[NM_ATT_IPACC_DST_IP]] +==== RSL Destination IP Address + +The value part of this attribute has a length of 4 octets and is encoded +as IPv4 address in network byte order. + +[width="40%",cols="90%,10%"] +[grid="none"] +|=== +| Attribute Identifier (0x80) | 1 +| IPv4 Address (MSB first) | 2-5 +|=== + + +[[NM_ATT_IPACC_DST_IP_PORT]] +==== RSL Destination TCP Port + +The value part of this attribute has a length of 2 octets and contains +the TCP destination port for the RSL connection, encoded in network byte +order. + +[width="40%",cols="90%,10%"] +[grid="none"] +|=== +| Attribute Identifier (0x81) | 1 +| Port number (MSB first) | 2-3 +|=== + + +[[NM_ATT_IPACC_STREAM_ID]] +==== RSL IPA Stream ID + +The value part of this attribute has a length of one octet and specifies +the IPA stream ID to be used for the RSL connection of this TRX. + +[width="40%",cols="90%,10%"] +[grid="none"] +|=== +| Attribute Identifier (0x85) | 1 +| Stream ID | 2 +|=== + + +[[NM_ATT_IPACC_RAC]] +==== GPRS Routing Area Code + +The value part of the GPRS Routing Area code consist of a single octet +encoding the GPRS Routing Area Code. + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_GPRS_PAGING_CFG]] +==== GPRS Paging Configuration + +The value part of this attribute consists of two octets encoded as +follows: + +[options="header"] +[cols="10%,90%"] +|=== +| Offset | Description +| 0 | GPRS Paging repeat time in units of 50ms intervals +| 1 | GPRS Paging repeat count +|=== + + +[[NM_ATT_IPACC_NSEI]] +==== GPRS NSEI + +The value part of the GPRS NSEI is encoded as 16bit integer value in +network byte order. + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_BVCI]] +==== GPRS BVCI + +The value part of this attribute consists of two octets encoding the +BSSGP Virtual Circuit Identifier (BVCI) as unsigned 16 bit integer in +network byte order. + + +[[NM_ATT_IPACC_NSVCI]] +==== GPRS NSVCI + +The value part of the GPRS NSVCI attribute is a 16bit unsigned integer +in network byte order, encoding the GPRS NSVCI as specified in 3GPP TS +08.16. + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_NS_CFG]] +==== GPRS NS Configuration + +The value part of the GPRS NS Configuration consist of an array of 7 octets, each +describing one GPRS NS related timer: + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_BSSGP_CFG]] +==== GPRS BSSGP Configuration + +The value part of the GPRS BSSGP configuration consists of an array of +11 octets, each describing one GPRS BSSGP related timer: + +[options="header"] +[cols="10%,90%"] +|=== +| Offset | Description +| 0 | Blocking Timer (T1) +| 1 | Blocking Retries +| 2 | Unblocking Retries +| 3 | Reset Timer (T2) +| 4 | Reset Retries +| 5 | Suspend Timer (T3) in units of 100ms +| 6 | Suspend Retries +| 7 | Resume Timer (T4) in units of 100ms +| 8 | Resume Retries +| 9 | Capability Update Timer (T5) +| 10 | Capability Update Retries +|=== + +The detailed description of the meaning of those timers is given in the +GPRS BSSGP specification 3GPP TS 08.18. + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_NS_LINK_CFG]] +==== GPRS NS Link Configuration + +The content of this attribute is 8 octets long and encoded as follows: +[options="header"] +[cols="10%,10%,80%"] +|=== +| Offset | Length | Description +| 0 | 2 | GPRS-NS Remote UDP Port Number (SGSN side) +| 2 | 4 | GPRS-NS Remote IPv4 Address (SGSN side) +| 6 | 2 | GPRS-NS Local UDP Port Number (BTS side) +|=== + +All values are encoded in network byte order. + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_RLC_CFG]] +==== GPRS RLC Configuration + +The value part of the GPRS RLC Configuration consists of an array of 9 +octets, each describing a RLC timer: + +[options="header"] +[width="60%",cols="10%,80%,10%"] +|=== +| Offset | Description | Unit +| 0 | GPRS RLC Timer T3142 | s +| 1 | GPRS RLC Timer T3169 | s +| 2 | GPRS RLC Timer T3191 | s +| 3 | GPRS RLC Timer T3193 | 10ms +| 4 | GPRS RLC Timer T3195 | s +| 5 | GPRS RLC Timer T3101 | s +| 6 | GPRS RLC Timer T3103 | s +| 7 | GPRS RLC Timer T3105 | s +| 8 | GPRS RLC CV Countdown | - +|=== + +The meaning of the RLC timers are specified in 3GPP TS 04.60. + +The countdown value specifies the RLC CV value from which the countdown +procedure is started. + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_CODING_SCHEMES]] +==== GPRS Coding Schemes + +The value part of the GPRS Coding Schemes consists of two octets +encoding the available GPRS and EDGE coding schemes. + +[options="header"] +|=== +| *bit* | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 +| byte at offset 0 | MCS9 | x | x | x | CS4 | CS3 | CS2 | CS1 +| byte at offset 1 | MCS8 | MCS7| MCS6 | MCS5 | MCS4| MCS3 | MCS2 | MCS1 +|=== + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_RLC_CFG_2]] +==== GPRS RLC Configuration 2 + +The value part of this attribute is 8 octets long and encoded as +follows: +[options="header"] +[width="60%",cols="10%,10%,70%,10%"] +|=== +| Offset | Length | Description | Unit +| 0 | 2 | Downlink TBF Extension Timer | 10ms +| 2 | 2 | Uplink TBF Extension Timer | 10ms +| 4 | 2 | Initial GPRS Coding Scheme | - +|=== + +The Initial GPRS Coding Scheme is encoded as follows: +[options="header"] +[width="40%",cols="50%,50%"] +|=== +| Value | Description +| 1 | CS 1 +| 2 | CS 2 +| 3 | CS 3 +| 4 | CS 4 +|=== + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + + +[[NM_ATT_IPACC_RLC_CFG_3]] +==== GPRS RLC Configuration 3 + +The content of this attribute contains information about the initial MCS +used for new EDGE TBFs. + +It is encoded as follows: +[options="header"] +[width="40%",cols="50%,50%"] +|=== +| Value | Description +| 1 | MCS 1 +| 2 | MCS 2 +| 3 | MCS 3 +| 4 | MCS 4 +| 5 | MCS 5 +| 6 | MCS 6 +| 7 | MCS 7 +| 8 | MCS 8 +| 9 | MCS 9 +|=== + +The content of this attribute is not used by OsmoBTS, but +simply passed to OsmoPCU connected to the PCU socket. + +=== A-bis OML Initialization / BTS bring-up + +At the time an Abis/IP BTS connects to via OML to the BSC, it is +initialized according to the procedures described in 3GPP TS 12.21 as +amended in this document. + +Each Managed Object (MO) is separately initialized. The initialization +sequence and parameters differ slightly depending on the MO involved. + +Some parts of the sequences described below are optional, such as the +Software activation. In the OsmoBTS case, the software is nod modular +and thus all MOs start with the software fully activated. Thus, no +__Software Activate Request__ is being sent by the MO to the BSC, nor +does the BSC need to initialize the __Activate Software__ procedure. + +Still, the full sequences are shown in order to explain the Abis/IP +protocol. + +Also, the initial state of the MOs at time of OML connection +initialization is not always guaranteed to be Disabled/Notinstalled. +Rather, the BSC implementation has to deal with the initial state as +reported by the MOs at time of re-connection. + +==== Site Manager MO Initialization + +.A-bis OML Initialization of Site Manager MO +["mscgen"] +---- +include::oml-mo-sitemgr.msc[] +---- + +As the Site Manager MO does not depend on other MOs, nor does it have an +Administrative state (__Locked/Unlocked__), it immediately ends up in the +__Enabled__ state. + +==== BTS MO Initialization + +.A-bis OML Initialization of BTS MO +["mscgen"] +---- +include::oml-mo-bts.msc[] +---- + +As can be seen in the BTS MO, its state is + +* Availability state __Dependency__, meaning it depends on other MOs to + be initialized before becoming enabled. +* Administrative state __Locked__, as the object is first waiting to + receive attributes in the __Locked__ state, before the __Change + Administrative State (Unlocked)__ procedure is used to request + transitioning into Unlocked state. + +==== Baseband Transceiver MO Initialization + +.A-bis OML Initialization of Baseband Transceiver MO +["mscgen"] +---- +include::oml-mo-transceiver.msc[] +---- + +There is one Baseband Transceiver MO per TRX in the BTS. For a +multi-TRX BTS, the above procedure must be repeated for each TRX. + + +==== Radio Carrier MO Initialization + +.A-bis OML Initialization of Radio Carrier MO +["mscgen"] +---- +include::oml-mo-carrier.msc[] +---- + +There is one Radio Carrier MO per TRX in the BTS. For a multi-TRX BTS, +the above procedure must be repeated for each TRX. + + +==== Channel MO Initialization + +.A-bis OML Initialization of Radio Carrier MO +["mscgen"] +---- +include::oml-mo-channel.msc[] +---- + +There are 8 Timeslots in each TRX, and correspondingly 8 Channel MOs in +every TRX. The above procedure must thus be repeated for each timeslot +in each transceiver of the BTS. + + +==== Full Initialization of entire BTS + +Some of the steps are optional, as is their detailed ordering. In +reality, the procedures for different MOs may overlap. The message +sequence charts in this document have been hand-crafted to avoid such +overlap for the sake of clarity. + +[[oml-msc-1]] +.A-bis OML BTS bring-up (1/3) +["mscgen"] +---- +include::oml-startup.msc[] +---- + +As can be seen in <<oml-msc-1>>, after the OML TCP connection is +established + +. the identity is exchanged via IPA CCM, +. the BTS sends an 'OML EVENT STATE CHANGED REPORT' for every + Managed Object +. the BTS subsequently requests the activation of its 'Site Manager' Object + which the BSC performs by the 'Activate SW' command. +. After successful activation of the software in the Site Manager, +.. the state changes to 'Enabled', and an event report is generated + accordingly +.. the BSC is notified about the SW activation in an associated report +. Finally, the BSC requests the start of the Site Manager +.. using the 'OPSTART' command, +.. which is subsequently acknowledged by the Site Manager. + +[[oml-msc-2]] +.A-bis OML BTS bring-up (2/3) +["mscgen"] +---- +include::oml-startup2.msc[] +---- + +[[oml-msc-3]] +.A-bis OML BTS bring-up (3/3) +["mscgen"] +---- +include::oml-startup3.msc[] +---- + +In <<oml-msc-2>>, we can see + +. Software Activation and associated state transitions of the BTS MO +. Setting of the BTS Attributes followed by OPSTART +. Software Activation and associated state transitions of the 'Baseband + Transceiver' MO +. Software Activation and associated state transitions of the 'Radio + Carrier' MO +. Once the 'Baseband Transceiver' MO has its software activated, the + 'Channel' MOs (one for each timeslot) indicate their state change and + software activation, too. + +In <<oml-msc-3>>, we can see + +. The 'Radio Carrier' MO Software Activation +. The Request to the 'Baseband Transceiver' MO to establish the RSL + signalling connection to the BSC. +. Subsequent OPSTART and Change of Administrative State on the 'Baseband + Transceiver' MO +. The following procedure for each of the 'Channel' MOs: +.. Setting the Channel Attributes (such as channel combination) +.. OPSTART +.. Changing the Administrative State to Unlocked +.. Subsequent State Change Event Report with the new state +. After all 'Channel' MOs are initialized, the Radio Carrier goes through + a similar procedure of +.. Setting its attributes +.. OPSTART +.. Changing its Administrative State to Unlocked +.. Subsequent State Change Event Report with the new State (Enabled/OK) +. All 'Channel' MOs now also report their state as Enabled/OK +. Finally, the BTS reports its state as Enabled/OK + |