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Technical Reference (Appendix)

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Technical reference for SS7 protocols and OmniSS7 implementation.

SS7 Protocol Stack


MAP Operation Codes

OperationOpcodePurpose
updateLocation2Register subscriber location
cancelLocation3Deregister from VLR
provideRoamingNumber4Request MSRN
sendRoutingInfo22Query call routing
mt-forwardSM44Deliver SMS to subscriber
sendRoutingInfoForSM45Query SMS routing
mo-forwardSM46Forward SMS from subscriber
sendAuthenticationInfo56Request auth vectors

TCAP Message Types

  • BEGIN - Start transaction
  • CONTINUE - Mid-transaction
  • END - Final response
  • ABORT - Cancel transaction

SCCP Addressing

Global Title Formats

  • E.164 - International phone number (e.g., 447712345678)
  • E.212 - IMSI format (e.g., 234509876543210)
  • E.214 - Point code format

Subsystem Numbers (SSN)

  • SSN 6: HLR
  • SSN 7: VLR
  • SSN 8: MSC/SMSC
  • SSN 9: GMLC
  • SSN 10: SGSN

SMS TPDU

Message Types

  • SMS-DELIVER (MT) - Network to mobile
  • SMS-SUBMIT (MO) - Mobile to network
  • SMS-STATUS-REPORT - Delivery status
  • SMS-COMMAND - Remote command

Character Encodings

  • GSM7 - 7-bit GSM alphabet (160 chars per SMS)
  • UCS2 - 16-bit Unicode (70 chars per SMS)
  • 8-bit - Binary data (140 bytes per SMS)

M3UA States

  • DOWN - No SCTP connection
  • CONNECTING - SCTP connecting
  • ASPUP_SENT - Waiting for ASPUP ACK
  • INACTIVE - ASP up but not active
  • ASPAC_SENT - Waiting for ASPAC ACK
  • ACTIVE - Ready for traffic

Common SS7 Point Codes

Point codes are typically 14-bit (ITU) or 24-bit (ANSI) values.

Example Format (ITU):

  • Network: 3 bits
  • Cluster: 8 bits
  • Member: 3 bits

SCCP Error Codes

  • 0 - No translation for address
  • 1 - No translation for specific address
  • 2 - Subsystem congestion
  • 3 - Subsystem failure
  • 4 - Unequipped user
  • 5 - MTP failure
  • 6 - Network congestion
  • 7 - Unqualified
  • 8 - Error in message transport

MAP Error Codes

CodeErrorDescription
1unknownSubscriberSubscriber not in HLR
27absentSubscriberSubscriber not reachable
34systemFailureNetwork failure
35dataMissingRequired data not available
36unexpectedDataValueInvalid parameter value


OmniSS7 by Omnitouch Network Services