Ybts socket protocol

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Signalling

Protocol type: Packet oriented

Packet format:

Name Description Length Presence Note
Primitive Packet description 1 Mandatory The most significant bit will indicate if the packet is connection related
If not set the packet header will contain the connection id field
If set the packet will not contain the connection id field
Info Extended info 1 Mandatory Interpreted according to primitive and packet data
ConnectionId Unsigned integer in network byte order 2 Conditional Present only if primitive most significant bit is not set
Data Packet data 0-n Optional

Primitives with code 0-127 are associated with a communication channel and its ID is presen after the Info field. Primitives with code 128-255 are not associated with a channel and Data (if present) follows immediately after the Info field.

Primitive

Value Name Sender Description Note Available in release
0 L3Message Both Connection related L3 message The packet carries a connection related L3 message 1
1 ConnLost <YBTSPeer> Connection abnormally released The <YBTSPeer> notifies about connection lost
No response is required
1
2 ConnRelease YBTS Request connection release YBTS requests a connection release
No response is required
1
3 StartMedia YBTS Request media channel YBTS requests changing the channel mode to allow traffic
On success MediaStarted is notified, on error a MediaError is reported
1
4 StopMedia YBTS Request stopping media YBTS requests media traffic to stop
No response is required
1
5 AllocMedia YBTS Request reservation of a traffic channel YBTS requests having a traffic channel allocated
In case of error a MediaError is reported
1
6 MediaError <YBTSPeer> Notifies about a traffic channel error This is sent in case of allocation failure or channel mode change failure 1
7 MediaStarted <YBTSPeer> Notifies that the traffic channel has started This is sent to confirm a StartMedia request 1
8 EstablishSAPI Both Request or notification for SAPI establishment This should be used for SAPI 1-3, SAPI 0 is established by default 1
9 PhysicalInfo <YBTSPeer> Physical channel information report Provides information about uplink physical channel 4
10 HandoverRequired <YBTSPeer> Outbound handover required Provides list of candidate cells and MS measured levels 4
11 HandoverAck <YBTSPeer> Inbound handover acknowledge Confirms resource allocation, carries RR HANDOVER COMMAND 4
 ? StartCiphering YBTS Request ciphering start To be discussed: The message may carry a RR CIPHERING MODE COMMAND
64 GprsAttachReq <YBTSPeer> GPRS Attach Request from MS This message is repeated as attach procedure progresses 4
65 GprsAttachLBO YBTS Attach Accept with Local Breakout Attach procedure continues with locally provided connectivity 4
66 GprsAttachOk YBTS Attach Accept through core network Attach procedure continues with data going through the core network 4
67 GprsAttachRej YBTS Attach is rejected by network The connection is closed when this message is sent or received 4
68 GprsIdentityReq YBTS The MS is requested to send the IMSI identity A new GprsAttachReq is expected after receiving IMSI 4
69 GprsAuthRequest YBTS The MS is requested to authenticate A new GprsAttachReq is expected after successful authentication 4
70 GprsDetach Both GPRS is being detached either by MS or by network The connection is closed when this message is sent or received 4
71 PdpActivate Both PDP Context creation is requested or acknowledged The reply parameter indicates a response 4
72 PdpModify Both PDP Context modification is requested or acknowledged The reply parameter indicates a response 4
73 PdpDeactivate Both A PDP Context is to be deleted There is no answer, it is assumed to always succeed 4
128 Handshake Both Handshake This is the first message exchanged on signalling interface.
Sent by <YBTSPeer>. Response: Handshake
1
129 RadioReady <YBTSPeer> Radio ready notification This message indicates the radio side is functional 1
130 StartPaging YBTS Paging start request This message request paging. It will transport a mobile identity 1
131 StopPaging YBTS Paging stop request This message request paging. It will transport a mobile identity 1
132 NeighborsList YBTS Update the list of neighbor cells The data holds a list of cells ordered by ARFCN 4
133 HandoverRequest YBTS Request inbound handover resources The Handover Reference must be handled by YBTS 4
134 HandoverReject <YBTSPeer> Indicates handover allocation failure 4
135 Stop <YBTSPeer> Application stopping notification YBTS will stop. It may not restart if a non retryable radio error is received 5
255 Heartbeat Both Connection idle heartbeat The packet don't carry data or connection id field
It must be sent on idle connection
Interval: ? seconds
1

Info

  • L3Message, EstablishSAPI:
    • Bit 7: Set if message is for SACCH
    • Bits 0-2 contains the SAPI
  • Handshake:
    • Bits 0-3: Protocol version. Current: 0
    • Bit 7: MSC/SGSN identity. This bit must be the same on both ends of a connection
    • Bits 4-6: Reserved, must be 0
  • StartMedia
    • Codes the channel traffic type, 0-3 (0 = Signaling only, 1-3 = GSM voice v...)
  • StartPaging
    • Codes the requested paged channel type (0 = Voice, 1 = SMS, 2 = SS)
  • MediaError
    • L3 CC Cause code (similar to Q.850)
  • HandoverRequest, HandoverAck, HandoverReject
    • Handover reference used to match Ack to Request
  • GprsDetach
    • Detach reason flags, bit 3 (0x08) indicates power off
  • GprsAttachReq
    • For a routing area update procedure, the message may also contain a pdps parameter detailing the known active PDP contexts from the point a view of the MS. If the MS doesn't provide the information, the parameter will arrive as 0xffff
  • GprsAttachOk
    • For a routing area update procedure, the message will also contain a pdps parameter listing active PDP contexts, a llcsapis parameter listing used LLC SAPIs and a tids parameter listing transaction IDs used by the MS for each PDP context
  • Stop
    • Stopping reason (Normal/RadioLost/InternalError/RadioExiting/RadioError)


Data

  • StartPaging, StopPaging
    • Mobile identity: TMSIxxxxxxxxxxxxxxxx (hex digits) or IMSIdddddddddddddddddddddddddddddd (BCD digits) in identity parameter
    • if mobile identity is TMSI, StartPaging will also contain the IMSI in imsi parameter
  • PhysicalInfo
    • Human-readable string describing physical level information
  • NeighborsList
    • String: BAND ARFCN1:BSIC1:CELLID1 ARFCN2:BSIC2:CELLID2 ...
  • HandoverRequired
    • String: MY_LEVEL LEVEL1:CELLID1 LEVEL2:CELLID2 ...
  • HandoverAck
    • Binary RR Handover Command
  • GprsAttachReq, GprsAttachOk, GprsAuthRequest, PdpActivate, PdpModify, PdpDeactivate
    • List of space separated tag=value parameters
  • Stop
    • List of space separated tag=value parameters

Media

Protocol type: Packet oriented

Packet format:

2 bytes connection id: unsigned integer in network byte order
0..n bytes media data

Logging

Protocol type: Packet oriented

Packet format:

Byte 0 Debug type Bytes 1..n Available in release
0xff Output Text 1
Bits 6-7: 0 Debug/Alarm with syslog level set in bits 0-5
Output if log level is not 0..7
Text 1
Bits 6-7: 3 Relay Output Text + 2 * NULL 4
Bits 6-7: 2 Relay Debug with level set in bits 0-3 Text + 2 * NULL 4
Bits 6-7: 1 Relay Alarm with level set in bits 0-3 Text + 3 * NULL + Component + NULL + Alarm Info 4

Command

Protocol type: Packet oriented

Command: 1..n bytes single line of text, up to 1023 characters

Response: 1..n bytes text, may include \n line separators