diff options
Diffstat (limited to 'doc/manuals/abis/rsl.adoc')
| -rw-r--r-- | doc/manuals/abis/rsl.adoc | 944 |
1 files changed, 944 insertions, 0 deletions
diff --git a/doc/manuals/abis/rsl.adoc b/doc/manuals/abis/rsl.adoc new file mode 100644 index 00000000..33ae26d6 --- /dev/null +++ b/doc/manuals/abis/rsl.adoc @@ -0,0 +1,944 @@ +== Radio Signalling Link (RSL) + +=== List of Messages + +The following tables list the RSL messages used by OsmoBTS A-bis/IP, +grouped by their level of compliance with 3GPP TS 08.58. + +==== Messages Compliant With TS 08.58 + +Specific additions and limitations apply, see the linked sections. + +.Messages compliant with TS 08.58 +[options="header",cols="10%,20%,45%,5%,20%"] +|=== +| TS 08.58 § | This document § | Message | <-/-> | Received/Sent by OsmoBTS +5+<| *Radio link layer management messages* +| 8.3.1 | - | DATA REQUEST | <- | Received +| 8.3.2 | - | DATA INDICATION | -> | Sent +| 8.3.3 | - | ERROR INDICATION | -> | Sent +| 8.3.4 | - | ESTABLISH REQUEST | <- | Received +| 8.3.5 | - | ESTABLISH CONFIRM | -> | Sent +| 8.3.6 | - | ESTABLISH INDICATION | -> | Sent +| 8.3.7 | - | RELEASE REQUEST | <- | Received +| 8.3.8 | - | RELEASE CONFIRM | -> | Sent +| 8.3.9 | - | RELEASE INDICATION | -> | Sent +| 8.3.10 | - | UNIT DATA REQUEST | <- | Received +| 8.3.11 | - | UNIT DATA INDICATION | -> | Sent +5+<| *DEDICATED CHANNEL MANAGEMENT MESSAGES* +| 8.4.1 | <<CHANNEL_ACTIVATION>> | CHANNEL ACTIVATION | <- | Received +| 8.4.2 | <<CHANNEL_ACTIVATION>> | CHANNEL ACTIVATION ACKNOWLEDGE | -> | Sent +| 8.4.3 | <<CHANNEL_ACTIVATION>> | CHANNEL ACTIVATION NEGATIVE ACKNOWLEDGE | -> | Sent +| 8.4.4 | - | CONNECTION FAILURE INDICATION | -> | Sent +| 8.4.5 | - | DEACTIVATE SACCH | <- | Received +| 8.4.6 | - | ENCRYPTION COMMAND | <- | Received +| 8.4.7 | - | HANDOVER DETECTION | -> | Sent +| 8.4.8 | <<MEASUREMENT_RESULT>> | MEASUREMENT RESULT | -> | Sent +| 8.4.9 | <<MODE_MODIFY>> | MODE MODIFY | <- | Received +| 8.4.10 | - | MODE MODIFY ACKNOWLEDGE | -> | Sent +| 8.4.11 | - | MODE MODIFY NEGATIVE ACKNOWLEDGE | -> | Sent +| 8.4.14 | - | RF CHANNEL RELEASE | <- | Received +| 8.4.15 | <<MS_POWER_CONTROL>> | MS POWER CONTROL | <- | Received +| 8.4.19 | - | RF CHANNEL RELEASE ACKNOWLEDGE | -> | Sent +| 8.4.20 | <<SACCH_INFO_MODIFY>> | SACCH INFO MODIFY | <- | Received +5+<| *COMMON CHANNEL MANAGEMENT MESSAGES* +| 8.5.1 | <<BCCH_INFORMATION>> | BCCH INFORMATION | <- | Received +| 8.5.2 | - | CCCH LOAD INDICATION | -> | Sent +| 8.5.3 | <<CHANNEL_REQUIRED>> | CHANNEL REQUIRED | -> | Sent +| 8.5.5 | <<PAGING_COMMAND>> | PAGING COMMAND | <- | Received +| 8.5.6 | - | IMMEDIATE ASSIGN COMMAND | <- | Received +| 8.5.8 | <<SMS_BROADCAST_COMMAND>> | SMS BROADCAST COMMAND | <- | Received +5+<| *TRX MANAGEMENT MESSAGES* +| 8.6.1 | <<RF_RESOURCE_INDICATION>> | RF RESOURCE INDICATION | -> | Sent +| 8.6.2 | <<SACCH_FILLING>> | SACCH FILLING | <- | Received +| 8.6.4 | - | ERROR REPORT | -> | Sent +|=== + +==== Messages Specific to OsmoBTS + +.Messages specific to OsmoBTS, not found in 3GPP TS 08.58 +[options="header",cols="15%,15%,45%,5%,20%"] +|=== +2+| This document § | Message | <-/-> | Received/Sent by OsmoBTS +5+<| *User Plane Transport Management* (<<user_plane_txp_mgmt>>) +.3+.| <<rsl_crcx>> | <<rsl_crcx_msg>> | RSL Create Connection (CRCX) | <- | Received + | <<rsl_crcx_msg_ack>> | RSL Create Connection (CRCX) ACK | -> | Sent + | <<rsl_crcx_msg_nack>> | RSL Create Connection (CRCX) NACK | -> | Sent +.3+.| <<rsl_mdcx>> | <<rsl_mdcx_msg>> | RSL Modify Connection (MDCX) | <- | Received + | <<rsl_mdcx_msg_ack>> | RSL Modify Connection (MDCX) ACK | -> | Sent + | <<rsl_mdcx_msg_nack>> | RSL Modify Connection (MDCX) NACK | -> | Sent +.3+.| <<rsl_dlcx>> | <<rsl_dlcx_msg>> | RSL Delete Connection (DLCX) | <- | Received + | <<rsl_dlcx_msg_ack>> | RSL Delete Connection (DLCX) ACK | -> | Sent + | <<rsl_dlcx_msg_nack>> | RSL Delete Connection (DLCX) NACK | -> | Sent + | <<rsl_dlcx_ind>> | <<rsl_dlcx_ind_msg>> | RSL Delete Connection (DLCX) Indication | -> | Sent +5+<| *IPA style PDCH Management* (<<ipa_style_pdch_mgmt>>) +.3+.| <<pdch_act>> | <<rsl_pdch_act>> | RSL PDCH Activation | <- | Received + | <<rsl_pdch_act_ack>> | RSL PDCH Activation ACK | -> | Sent + | <<rsl_pdch_act_nack>> | RSL PDCH Activation NACK | -> | Sent +.3+.| <<pdch_deact>> | <<rsl_pdch_deact>> | RSL PDCH Deactivation | <- | Received + | <<rsl_pdch_deact_ack>> | RSL PDCH Deactivation ACK | -> | Sent + | <<rsl_pdch_deact_nack>> | RSL PDCH Deactivation NACK | -> | Sent +|=== + +==== Messages Not Implemented by OsmoBTS + +.3GPP TS 08.58 messages not implemented by OsmoBTS +[options="header",cols="10%,90%"] +|=== +| TS 08.58 § | Message +2+<| *DEDICATED CHANNEL MANAGEMENT MESSAGES* +| 8.4.12 | PHYSICAL CONTEXT REQUEST +| 8.4.13 | PHYSICAL CONTEXT CONFIRM +| 8.4.16 | BS POWER CONTROL +| 8.4.17 | PREPROCESS CONFIGURE +| 8.4.18 | PREPROCESSED MEASUREMENT RESULT +| 8.4.21 | TALKER DETECTION +| 8.4.22 | LISTENER DETECTION +| 8.4.23 | REMOTE CODEC CONFIGURATION REPORT +| 8.4.24 | ROUND TRIP DELAY REPORT +| 8.4.25 | PRE-HANDOVER NOTIFICATION +| 8.4.26 | MULTIRATE CODEC MODIFICATION REQUEST +| 8.4.27 | MULTIRATE CODEC MODIFICATION ACKNOWLEDGE +| 8.4.28 | MULTIRATE CODEC MODIFICATION NEGATIVE ACKNOWLEDGE +| 8.4.29 | MULTIRATE CODEC MODIFICATION PERFORMED +| 8.4.30 | TFO REPORT +| 8.4.31 | TFO MODIFICATION REQUEST +2+<| *COMMON CHANNEL MANAGEMENT MESSAGES* +| 8.5.4 | DELETE INDICATION +| 8.5.7 | SMS BROADCAST REQUEST +| 8.5.9 | CBCH LOAD INDICATION +| 8.5.10 | NOTIFICATION COMMAND +2+<| *TRX MANAGEMENT MESSAGES* +| 8.6.3 | OVERLOAD +2+<| *LOCATION SERVICES MESSAGES* +| 8.7.1 | LOCATION INFORMATION +|=== + + +=== Message Limitation Details + +[[CHANNEL_ACTIVATION]] +==== Channel Activation + +When used on a timeslot using the non-standard channel combination +'NM_CHANC_OSMO_TCHFull_TCHHalf_PDCH' as configured by OML, the regular +RSL channel activation procedures can not only be used for activation +of circuit-switched channels, but also for activation of a PDCH. + +See <<OSMOCOM_DYN_TS>>. + +NOTE:: Do not confuse this with the IPA style _PDCH ACT_ type +dynamic PDCH protocol employed by nanoBTS devices (<<ipa_style_pdch_mgmt>>). + +[[MEASUREMENT_RESULT]] +==== Measurement Result + +Conforms to 3GPP TS 08.58 § 8.4.8 with this limitation: + +._Measurement Result_ IE limitations +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.37 | MS Timing Offset | never sent by OsmoBTS +|=== + +[[MODE_MODIFY]] +==== Mode Modify + +Conforms to 3GPP TS 08.58 § 8.4.9 with these limitations: + +._Mode Modify_ IE limitations +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.45 | Main channel reference | _ignored_ +| 9.3.53 | MultiRate Control | _ignored_ +| 9.3.54 | Supported Codec Types | _ignored_ +|=== + +[[MS_POWER_CONTROL]] +==== MS Power Control + +Conforms to 3GPP TS 08.58 § 8.4.15 with these limitations: + +._MS Power Control_ IE limitations +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.31 | MS Power Parameters | _ignored_ +|=== + + +[[SACCH_INFO_MODIFY]] +==== SACCH Info Modify + +Conforms to 3GPP TS 08.58 § 8.4.20, with these exceptions: + +._SACCH Info Modify_ IE limitations +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.30 | System Info Type | See below for available types +| 9.3.23 | Starting Time | not supported, provokes an _Error Report_ response +|=== + +._System Info Type_ values that can occur on the SACCH +[options="header",width="50%",cols="20%,80%"] +|=== +| Value | Name +| 0x05 | RSL_SYSTEM_INFO_5 +| 0x06 | RSL_SYSTEM_INFO_6 +| 0x0d | RSL_SYSTEM_INFO_5bis +| 0x0e | RSL_SYSTEM_INFO_5ter +| 0x47 | RSL_EXT_MEAS_ORDER +| 0x48 | RSL_MEAS_INFO +|=== + +[[BCCH_INFORMATION]] +==== BCCH Information + +Conforms to 3GPP TS 08.58 § 8.5.1, with these limitations and extensions: + +._BCCH Information_ IE details +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.30 | System Info Type | See <<SACCH_INFO_MODIFY>> for available types +| 9.3.11 | L3 Info | This IE may be included instead of a 9.3.39 _Full BCCH Info_ IE. + The _Full BCCH Info_ takes precedence over _L3 Info_. + To stop SI transmission, both of these IEs must be omitted. +|=== + + +[[CHANNEL_REQUIRED]] +==== Channel Required + +Conforms to 3GPP TS 08.58 § 8.5.3, with these limitations: + +._Channel Required_ message IE details +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.16 | Physical Context | never sent by OsmoBTS +|=== + + +[[PAGING_COMMAND]] +==== Paging Command + +Conforms to 3GPP TS 08.58 § 8.5.5, with these limitations: + +._Paging Command_ message IE details +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.49 | eMLPP Priority | _ignored_ +|=== + +NOTE: If adding the identity to the paging queue fails, the BSC is not notified +in any way. + +[[SMS_BROADCAST_COMMAND]] +=== SMS Broadcast Command + +Conforms to 3GPP TS 08.58 § 8.5.8, with these limitations: + +._Broadcast Command_ message IE details +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.44 | SMSCB Channel Indicator | _ignored_ +|=== + + +[[RF_RESOURCE_INDICATION]] +==== RF Resource Indication + +This message does not conform to 3GPP TS 08.58 § 8.6.1, in that it omits the +_Resource Information_ IE that would contain the actual payload data, which +renders this message void. + +._RF Resource Indication_ message IE exceptions +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.21 | Resource Information | OsmoBTS omits this IE, though TS 08.58 + specifies it as mandatory. +|=== + + +[[SACCH_FILLING]] +==== SACCH Filling + +Conforms to 3GPP TS 08.58 § 8.6.2, with these limitations: + +._SACCH Filling_ message IE limitations +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.3.30 | System Info Type | See <<SACCH_INFO_MODIFY>> for available types +| 9.3.23 | Starting Time | _ignored_ +|=== + + +[[user_plane_txp_mgmt]] +=== User Plane Transport Management + +This chapter defines the A-bis/IP specific RSL procedures that are +introduced in addition to the 3GPP TS 08.58 standard procedures. + +In classic A-bis over E1, user plane traffic is carried over 16kBps +sub-slots of 64kBps E1 time-slots according to ETSI/3GPP TS 08.60. As +the E1 line is a dedicated line between BTS and BSC, no further +addressing information is required. + +In A-bis/IP as described by the present document, new RSL procedures +have been introduced to deal with the different properties of +the underlying IP based transport medium. + +[[rsl_crcx]] +==== RSL Create Connection (CRCX) + +This procedure is used by the BSC to request the BTS to allocate + bind +to a BTS-local UDP port for the subsequent transmission of user-plane +data via RTP. + +To do so, the BSC sends the *Create Connection (CRCX)* message. In case of +successful outcome, the BTS responds with *Create Connection (CRCX) +ACK*. In case of any error, the BTS responds with *Create Connection +(CRCX) NACK*. + +See <<rsl_crcx_msg>>, <<rsl_crcx_msg_ack>>, <<rsl_crcx_msg_nack>> + +[[rsl_mdcx]] +==== RSL Modify Connection (MDCX) + +This procedure is used by the BSC to request the BTS to modify an +already-bound BTS-local UDP port for user-plane RTP. It is used in +particular to configure the remote IP address and UDP port to which the +BTS shall send user-plane RTP traffic. This remote address is normally +either a Media Gateway (MGW) of some sort, but could also be the RTP +socket of the corresponding other leg of a mobile-to-mobile call. + +To modify a user-plane connection, the BSC sends the *Modify Connection* +message. In case of successful outcome, the BTS responds with +*Modify Connection (MDCX) ACK*. In case of any error, the BTS responds +with *Modify Connection (MDCX) NACK*. + +See <<rsl_mdcx_msg>>, <<rsl_mdcx_msg_ack>>, <<rsl_mdcx_msg_nack>> + +[[rsl_dlcx]] +==== RSL Delete Connection (DLCX) + +This procedure is used by the BSC to request the BTS to delete an +already-existing BTS-local UDP port for user-plane RTP. + +To delete a user-plane connection, the BSC sends the *Delete Connection +(DLCX)* message. In case of successful outcome, the BTS responds with +*Delete Connection (DLCX) ACK*. In case of any error, the BTS responds +with *Delete Connection (DLCX) NACK*. + +See <<rsl_dlcx_msg>>, <<rsl_dlcx_msg_ack>>, <<rsl_dlcx_msg_nack>> + +[[rsl_dlcx_ind]] +==== RSL Delete Connection (DLCX) Indication + +When a BTS-local UDP connection for user-plane RTP is automatically +released at the time of RF CHANNEL RELEASE, the BTS sends a unilateral, +non-acknowledged *RSL Delete Connection (DLCX) Indication* to the BSC. + +See <<rsl_dlcx_ind_msg>> + + +[[rsl-dynamic-channels]] +=== Dynamic Channel Combinations + +In the classic data model established by ETSI/3GPP for A-bis, each +timeslot (channel) is configured using a static channel combination by +means of A-bis OML. Particularly in presence of GPRS services, this +is very unflexible and leads to inefficient use of air interface +resources. + +As such, several methods have been implemented to overcome this +limitation. The fundamental operation can be outlined like this: + +* Configuration of a particular _dynamic_ channel combination via OML +* activation of TCH works like on a classic TCH channel combination +* activation of PDCH requires some specific PDCH activation procedure + +There are two variants implemented in the OsmoBTS A-bis dialect: + +[[ipa_style_pdch_mgmt]] +==== IPA Style Dynamic Channels + +This method is used when OML uses 'NM_CHANC_IPAC_TCHFull_PDCH' (0x80) +as channel combination for the given time-slot. + +'IPA style' refers to 'ip.access' compatible PDCH activation and deactivation. + +When the IPA style dynamic channel combination _TCH/F or PDCH_ +is set, the non-standard 'PDCH ACTIVATE' (<<pdch_act>>) and 'PDCH +DEACTIVATE' (<<pdch_deact>>) procedures are used for switching an idle +channel into PDCH mode and back into idle mode. + +When the channel is used as TCH/F, regular circuit-switched activation +is performed, like on any traditional TCH/F. However, the BSC must +make sure to first disable the PDCH on the timeslot, before activating +it as TCH/F. Likewise, any circuit-switched TCH/F on the channel must +be deactivated using standard RSL signalling, before the specific PDCH +related procedures are used to enable the PDCH. + +[[pdch_act]] +===== PDCH Activate + +This procedure is used by the BSC to request the BTS to activate an +IPA style dynamic TCH/F+PDCH channel in PDCH mode. + +The operation is not supported on any other physical channel type. + +See <<rsl_pdch_act>>, <<rsl_pdch_act_ack>>, <<rsl_pdch_act_nack>> + +[[pdch_deact]] +===== PDCH Deactivate + +This procedure is used by the BSC to request the BTS to deactivate an +active PDCH on any an IPA style dynamic TCH/F+PDCH channel. + +The operation is not supported on any other physical channel type. + +See <<rsl_pdch_deact>>, <<rsl_pdch_deact_ack>>, <<rsl_pdch_deact_nack>> + +===== IPA Style Dynamic Switchover Example + +.Part 1: example for dynamic channel switchover, for IPA style dynamic timeslots +["mscgen"] +---- +include::dyn_ts_ipa_style1.msc[] +---- + +.Part 2: example for dynamic channel switchover, for IPA style dynamic timeslots +["mscgen"] +---- +include::dyn_ts_ipa_style2.msc[] +---- + + +[[OSMOCOM_DYN_TS]] +==== Osmocom Style Dynamic Channels + +This method is in use when OML uses +'NM_CHANC_OSMO_TCHFull_TCHHalf_PDCH' (0x90) for the given time-slot. + +The activation of PDCH is performed by using the regular 'RSL CHANNEL ACTIVATE' +procedure according to <<CHANNEL_ACTIVATION>>, with these modifications: + +* The 'C-bits' part of the 'Channel Number' IE take the non-standard binary + value 11000 (C5 thru C1 as seen in 3GPP TS 08.58 § 9.3.1). +* The 'A-bits' part of the 'Activation Type' IE take the non-standard binary + value 1111, with an additional fourth bit (add A4 to A3 thru A1 as seen in + 3GPP TS 08.58 § 9.3.3; all remaining reserved bits as well as the 'R' bit are + coded as zero). +* The normally mandatory 'Channel Mode' IE is omitted; none of the optional IEs + are included. + +Hence the message consists of exactly these IEs: + +.PDCH type _Channel Activation_ message IEs +[options="header",cols="10%,30%,60%"] +|=== +| TS 08.58 § | IE Name | Handling +| 9.1 | Message discriminator | Dedicated Channel Management +| 9.2 | Message type | CHANnel ACTIVation +| 9.3.1 | Channel number | 'C-bits' 11000, plus TS bits as usual +| 9.3.3 | Activation type | 'A-bits' 1111 +|=== + +===== Osmocom Style Dynamic Switchover Example + +.Part 1: example for dynamic channel switchover, for Osmocom style dynamic timeslots +["mscgen"] +---- +include::dyn_ts_osmocom_style1.msc[] +---- + +.Part 2: example for dynamic channel switchover, for Osmocom style dynamic timeslots +["mscgen"] +---- +include::dyn_ts_osmocom_style2.msc[] +---- + +=== Message Formats and Contents + +[[rsl_crcx_msg]] +==== Create Connection (CRCX) + +This message is sent by the BSC to the BTS to request the +creation of a user-plane RTP connection for the specified *Channel +number*. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Destination IP Address | <<RSL_IE_IPAC_REMOTE_IP>> | O | TV | 5 +| Destination IP Port | <<RSL_IE_IPAC_REMOTE_PORT>> | O | TV | 3 +| IP Speech Mode | <<RSL_IE_IPAC_SPEECH_MODE>> | O | TV | 2 +| RTP Payload Type 2 | <<RSL_IE_IPAC_RTP_PAYLOAD2>> | O | TV | 2 +|=== + +[[rsl_crcx_msg_ack]] +==== Create Connection (CRCX) ACK + +This message is sent by the BTS to the BSC to acknowledge the +successful outcome of creating a user-plane RTP connection. It is sent +in response to the *Create Connection (CRCX)*. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Connection Id | <<RSL_IE_IPAC_CONN_ID>> | M | TV | 3 +| Source IP Address | <<RSL_IE_IPAC_LOCAL_IP>> | O | TV | 5 +| Source IP Port | <<RSL_IE_IPAC_LOCAL_PORT>> | O | TV | 3 +| RTP Payload Type 2 | <<RSL_IE_IPAC_RTP_PAYLOAD2>> | O | TV | 2 +|=== + +[[rsl_crcx_msg_nack]] +==== Create Connection (CRCX) NACK + +This message is sent by the BTS to the BSC to signal the +unsuccessful outcome of creating a user-plane RTP connection. It is +sent in response to the *Create Connection (CRCX)*. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Destination IP Address | <<RSL_IE_IPAC_REMOTE_IP>> | O | TV | 5 +| Destination IP Port | <<RSL_IE_IPAC_REMOTE_PORT>> | O | TV | 3 +| Cause | 08.58 9.3.26 | O | TLV | >= 3 +|=== + + +[[rsl_mdcx_msg]] +==== Modify Connection (MDCX) + +This message is sent by the BSC to the BTS to modify the +properties of a user-plane RTP connection. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Connection Id | <<RSL_IE_IPAC_CONN_ID>> | O | TV | 3 +| Destination IP Address | <<RSL_IE_IPAC_REMOTE_IP>> | O | TV | 5 +| Destination IP Port | <<RSL_IE_IPAC_REMOTE_PORT>> | O | TV | 3 +| IP Speech Mode | <<RSL_IE_IPAC_SPEECH_MODE>> | O | TV | 2 +| RTP Payload Type 2 | <<RSL_IE_IPAC_RTP_PAYLOAD2>> | O | TV | 2 +|=== + +[[rsl_mdcx_msg_ack]] +==== Modify Connection (MDCX) ACK + +This message is sent by the BTS to the BSC to acknowledge the +successful modification of a user-plane RTP connection. It is sent in +response to a *Modify Connection (MDCX)* + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Connection Id | <<RSL_IE_IPAC_CONN_ID>> | O | TV | 3 +| Source IP Address | <<RSL_IE_IPAC_LOCAL_IP>> | C | TV | 5 +| Source IP Port | <<RSL_IE_IPAC_LOCAL_PORT>> | C | TV | 3 +| RTP Payload Type 2 | <<RSL_IE_IPAC_RTP_PAYLOAD2>> | O | TV | 2 +|=== + +[[rsl_mdcx_msg_nack]] +==== Modify Connection (MDCX) NACK + +This message is sent by the BTS to the BSC to signal the +unsuccessful outcome of modifying the user-plane RTP connection for the +specified Channel number. It is sent in response to the *Modify +Connection (MDCX)*. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Cause | 08.58 9.3.26 | M | TLV | >= 3 +|=== + +[[rsl_dlcx_ind_msg]] +==== Delete Connection (DLCX) Indication + +This message is sent by the BTS to indicate the automatic +deletion of a BTS-local UDP connection for user-plane RTP traffic at the +time of RF Channel release. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Connection Id | <<RSL_IE_IPAC_CONN_ID>> | M | TV | 3 +| Connection Id | <<RSL_IE_IPAC_CONN_STAT>> | M | TV | 3 +| Cause | 08.58 9.3.26 | M | TLV | >= 3 +|=== + +[[rsl_dlcx_msg]] +==== Delete Connection (DLCX) + +This message is sent by the BSC to the BTS to request the +disconnection of a user-plane RTP connection for the specified Channel +number. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Connection Id | <<RSL_IE_IPAC_CONN_ID>> | O | TV | 3 +|=== + +[[rsl_dlcx_msg_ack]] +==== Delete Connection (DLCX) ACK + +This message is sent by the BTS to signal the successful +outcome of deleting the user-plane RTP connection for the specified +Channel number. It is sent in response to the *Delete Connection +(DLCX)*. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Connection Id | <<RSL_IE_IPAC_CONN_ID>> | O | TV | 3 +| Connection Statistics | <<RSL_IE_IPAC_CONN_STAT>> | C | TV | 29 +|=== + +[[rsl_dlcx_msg_nack]] +==== Delete Connection (DLCX) NACK + +This message is sent by the BTS to signal the unsuccessful +outcome of deleting the user-plane RTP connection for the specified +Channel number. It is sent in response to the *Delete Connection +(DLCX)*. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Connection Id | <<RSL_IE_IPAC_CONN_ID>> | O | TV | 3 +| Cause | 08.58 9.3.26 | M | TLV | >= 3 +|=== + +[[rsl_pdch_act]] +==== PDCH Activate + +This message is sent by the BSC to request the activation of a PDCH on +a IPA style dynamic TCH/F+PDCH channel. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +|=== + +NOTE:: This message is *not* used by Osmocom style dynamic channels + +[[rsl_pdch_act_ack]] +==== PDCH Activate ACK + +This message is sent by the BTS to confirm the successful activation +of a PDCH on a IPA style dynamic TCH/F+PDCH channel. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Frame Number | 08.58 9.3.8 | O | TV | 3 +|=== + +NOTE:: This message is *not* used by Osmocom style dynamic channels + +[[rsl_pdch_act_nack]] +==== PDCH Activate NACK + +This message is sent by the BTS to reject the successful activation +of a PDCH on a IPA style dynamic TCH/F+PDCH channel. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Cause | 08.58 9.3.26 | M | TLV | >= 3 +|=== + +NOTE:: This message is *not* used by Osmocom style dynamic channels + +[[rsl_pdch_deact]] +==== PDCH Deactivate + +This message is sent by the BSC to request the deactivation of a PDCH +on a IPA style dynamic TCH/F+PDCH channel. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +|=== + +NOTE:: This message is *not* used by Osmocom style dynamic channels + +[[rsl_pdch_deact_ack]] +==== PDCH Deactivate ACK + +This message is sent by the BTS to confirm the successful deactivation +of a PDCH on a IPA style dynamic TCH/F+PDCH channel. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +|=== + +NOTE:: This message is *not* used by Osmocom style dynamic channels + +[[rsl_pdch_deact_nack]] +==== PDCH Deactivate NACK + +This message is sent by the BTS to reject the deactivation of a PDCH +on a IPA style dynamic TCH/F+PDCH channel. + +[options="header"] +[cols="30%,25%,15%,15%,15%"] +|=== +| INFORMATION ELEMENT | REFERENCE | PRESENCE | FORMAT | LENGTH +| Message discriminator | 08.58 9.1 | M | V | 1 +| Message type | <<own_msg_types>> | M | V | 1 +| Channel number | 08.58 9.3.1 | M | TV | 2 +| Cause | 08.58 9.3.26 | M | TLV | >= 3 +|=== + +NOTE:: This message is *not* used by Osmocom style dynamic channels + +=== Information Element Codings + +[[own_msg_types]] +==== A-bis/IP specific RSL Message discriminators + +The following message discriminators are used in addition to those +indicated in 3GPP TS 08.58 Section 9.1: + +.OsmoBTS specific new message discriminators +[options="header",cols="10%,50%,40%"] +|=== +| Message Type | Message | This document § +| 0x70 | Create Connection (CRCX) | <<rsl_crcx_msg>> +| 0x71 | Create Connection (CRCX) ACK | <<rsl_crcx_msg_ack>> +| 0x72 | Create Connection (CRCX) NACK | <<rsl_crcx_msg_nack>> +| 0x73 | Modify Connection (MDCX) | <<rsl_mdcx_msg>> +| 0x74 | Modify Connection (MDCX) ACK | <<rsl_mdcx_msg_ack>> +| 0x75 | Modify Connection (MDCX) NACK | <<rsl_mdcx_msg_nack>> +| 0x76 | Delete Connection (DLCX) Indication | <<rsl_dlcx_ind_msg>> +| 0x77 | Delete Connection (DLCX) | <<rsl_dlcx_msg>> +| 0x78 | Delete Connection (DLCX) ACK | <<rsl_dlcx_msg_ack>> +| 0x79 | Delete Connection (DLCX) NACK | <<rsl_dlcx_msg_nack>> +| 0x48 | PDCH Activate | <<rsl_pdch_act>> +| 0x49 | PDCH Activate ACK | <<rsl_pdch_act_ack>> +| 0x4a | PDCH Activate NACK | <<rsl_pdch_act_nack>> +| 0x4b | PDCH Deactivate | <<rsl_pdch_deact>> +| 0x4c | PDCH Deactivate ACK | <<rsl_pdch_deact_ack>> +| 0x4d | PDCH Deactivate NACK | <<rsl_pdch_deact_nack>> +|=== + +==== A-bis/IP specific RSL IEIs + +The following Information Element Identifiers (IEIs) are used in +addition to those indicated in 3GPP TS 08.58 Section 9.3: + +.A-bis/IP specific information elements +[options="header",cols="10%,50%,40%"] +|=== +| IEI | Name | This document § +| 0x01 | RSL_IE_CHAN_NR | <<RSL_IE_CHAN_NR>> +| 0xf0 | RSL_IE_IPAC_REMOTE_IP | <<RSL_IE_IPAC_REMOTE_IP>> +| 0xf1 | RSL_IE_IPAC_REMOTE_PORT | <<RSL_IE_IPAC_REMOTE_PORT>> +| 0xf3 | RSL_IE_IPAC_LOCAL_PORT | <<RSL_IE_IPAC_LOCAL_PORT>> +| 0xf4 | RSL_IE_IPAC_SPEECH_MODE | <<RSL_IE_IPAC_SPEECH_MODE>> +| 0xf5 | RSL_IE_IPAC_LOCAL_IP | <<RSL_IE_IPAC_LOCAL_IP>> +| 0xf6 | RSL_IE_IPAC_CONN_STAT | <<RSL_IE_IPAC_CONN_STAT>> +| 0xf8 | RSL_IE_IPAC_CONN_ID | <<RSL_IE_IPAC_CONN_ID>> +| 0xfc | RSL_IE_IPAC_RTP_PAYLOAD2 | <<RSL_IE_IPAC_RTP_PAYLOAD2>> +|=== + +[[RSL_IE_CHAN_NR]] +==== RSL_IE_CHAN_NR + +This information element is coded like 3GPP TS 08.58 Section 9.3.1, +but in addition supports the following extended coding: + +* C5..C1 bits 0b11000 for PDCH type channels + +The TN-Bits are not re-defined in this case but use the same encoding +as specified in TS 08.58 Section 9.3.1. + +NOTE:: The above extension is only valid on an Osmocom-style dynamic +channel, having configured the 'NM_CHANC_IPAC_TCHFull_PDCH' channel +combination by OML. + +[[RSL_IE_IPAC_REMOTE_IP]] +==== RSL_IE_IPAC_REMOTE_IP + +This information element contains the remote (MGW side) IPv4 address in +network byte order. It is encoded as fixed-size element with one byte +IEI followed by four bytes IPv4 address. + +[[RSL_IE_IPAC_REMOTE_PORT]] +==== RSL_IE_IPAC_REMOTE_PORT + +This information element contains the remote (MGW side) UDP port in +network byte order. It is encoded as fixed-size element with one byte +IEI followed by two bytes UDP port number. + +[[RSL_IE_IPAC_LOCAL_PORT]] +==== RSL_IE_IPAC_LOCAL_PORT + +This information element contains the local (BTS side) IPv4 address in +network byte order. It is encoded as fixed-size element with one byte +IEI followed by two bytes UDP port number. + +[[RSL_IE_IPAC_SPEECH_MODE]] +==== RSL_IE_IPAC_SPEECH_MODE + +This information element encodes the speech mode. It is set according +to the voice codec used on the connection. It is encoded as a fixed-size +element of two bytes, with one byte IEI followed by one byte Speech mode +indicator. + +.A-bis/IP Speech Mode Indicator Values +[options="header",width="40%",cols="20%,80%"] +|=== +| Value | Description +| 0x00 | TCH/F with FR codec +| 0x01 | TCH/F with EFR codec +| 0x02 | TCH/F with AMR codec +| 0x03 | TCH/H with HR codec +| 0x05 | TCH/H with AMR codec +|=== + +[[RSL_IE_IPAC_LOCAL_IP]] +==== RSL_IE_IPAC_LOCAL_IP + +This information element contains the local (BTS side) IPv4 address in +network byte order. It is encoded as fixed-size element with one byte +IEI followed by four bytes IPv4 address. + +[[RSL_IE_IPAC_CONN_STAT]] +==== RSL_IE_IPAC_CONN_STAT + +This information element contains statistics about the RTP connection. + +It is encoded as 29 bytes, with the first byte as IEI and 28 bytes +fixed-length payload encoded as follows: + +.A-bis/IP Connection Statistics +[options="header",width="60%",cols="15%,15%,70%"] +|=== +| Offset | Size | Description +| 0 | 4 | Total number of RTP packets sent +| 4 | 4 | Total number of octets sent +| 8 | 4 | Total number of RTP packets received +| 12 | 4 | Total number of octets received +| 16 | 4 | Total number of lost packets in Rx direction +| 20 | 4 | Inter-arrival Jitter +| 24 | 4 | Average transmission delay +|=== + +All the above values are encoded in network byte order. + +A detailed definition of the individual values is given in RFC 1889. + +[[RSL_IE_IPAC_CONN_ID]] +==== RSL_IE_IPAC_CONN_ID + +This IE is a TV with a value length of two bytes. The value is a 16 bit +connection ID in network byte order. + + +[[RSL_IE_IPAC_RTP_PAYLOAD2]] +==== RSL_IE_IPAC_RTP_PAYLOAD2 + +This information element contains the RTP payload identifier, which is +used in the PT (Payload Type) field of the RTP header in subsequent +transmissions of the RTP flow. + +=== A-bis RSL Initialization / BTS bring-up + +Upon receiving the 'IPA RSL CONNECT' OML message by the respective +'Baseband Transceiver' MO, the BTS proceeds with establishing a separate +TCP connection for the given TRX. + +[[rsl-msc-pri]] +.A-bis RSL BTS bring-up for primary TRX +["mscgen"] +---- +include::rsl-startup-pri.msc[] +---- + +[[rsl-msc-sec]] +.A-bis RSL BTS bring-up for secondary TRXs +["mscgen"] +---- +include::rsl-startup-sec.msc[] +---- + +The initialization of the primary and secondary TRX slightly differ, as +illustrated by the differences of <<rsl-msc-pri>> and <<rsl-msc-sec>>. +Since the secondary TRX has no BCCH, it does not (need to) receive any 'RSL +BCCH INFORMATION' messages from the BSC. + |