09.603GPPGeneral Packet Radio Service (GPRS)GPRS Tunnelling Protocol GPT) across the Gn and Gp InterfaceRelease 1998TS
In this sub-section a naming convention for GSNs is described.
It shall be possible to refer to a GSN by a logical name that shall then be translated into a physical IP address. Here a GSN naming convention is proposed which would make it possible for an internal GPRS DNS server to make the translation.
An example of how a logical name of a SGSN could look like is:
SGSNxxxx.MNCyyyy.MCCzzzz.GPRS; x,y and z shall be Hex coded digits.
Annex B (informative):
A method for sequence number checking
This annex describes a method to determine whether or not a received T-PDU is valid, for the Usage of the Sequence Number section, 126.96.36.199
This method deals with two distinct problems.
The first one is the ‘drifting’ between the Sequence Number value that we expect to receive in the light of the total number of T-PDU received for this tunnel (the Expected value), and the effective received value. The probability that the received T-PDU is not correct because not awaited is higher if the distance between Expected and received Sequence Numbers is high than if this distance is low. This leads to Condition 1. Its left part represents the distance between the Expected and received values, in a circular 65536 dimension.
The second one is the duplication of T-PDU frames within a given number of last received frames which have been accepted by the condition 1.
This leads to the following actions:
This operation shall start when the dialogue is established between the GSNs. When each T-PDU is received during the dialogue, if this T-PDU is valid, its Sequence Number shall be saved. The last ‘A’ saved Sequence Numbers represent the ‘Recorded Sequence Number Set’.
A received T-PDU sequence number is valid only if it satisfies both of the following conditions:
1) Min(Abs(E – r), Abs(r – 65536 – E), Abs(E – 65536 – r)) < ‘B’ Condition 1 Where: ‘E’ is the Expected Sequence Number and ‘r’ is the received Sequence Number.
2) The received Sequence Number is not a member of the Recorded Sequence Number Set. Condition 2
‘A’ and ‘B’ are parameters.The receiving GSN shall discard a received T-PDU with an invalid Sequence Number.
Abs(X) represents the absolute value of the number X.
Min(X,Y,Z) represents the lowest value taken from the numbers X, Y, and Z.
Annex C (informative):
Document change history
Updated with SMG#25. CR’s A001r2, A004r1, A005r2, A006r2, A007 and A010 are included.
Updated with SMG#26. CR’s A012r2, A013r1, A014r2, A015r1, A016r2, A017r1, A018r2, A20r1 and A021 are included.
CR A022r1 Modification of the coding of the Cause values of the Cause information elements.
One-step Approval Procedure OAP 9957: 1999-09-01 to 1999-12-31
CR A024r1 Corrections and clarifications.
CR A025r1 Charging ID to three GTP message types
CR A026 Modification of the definition of the length of the protocol messages.
CR A027r2 Information Elements: Clarification of the handling of the unused bits, re-definition of range.
CR A028r2 Clarification of the handling of protocol errors in the Error handling section.
CR A029 Update of the Protocol Configuration Options IE
Editorial correction to figures
Editorial correction to figures
CR A043Removal of not defined cause ‘TLLI Signature mismatch
CR A042 PDP Context IE
CR A041 PDP context establishment and restoration
CR A040r1 Correction of the value of parameter LLC Frame number within GTP header
CR A039r2 Alignment of the GSM 09.60 with GSM 09.02
CR A038r1 Addition of IMSI to SGSN Context Request
CR A037r1 Corrections and clarifications of the GSM 09.60 specification
CR A036r1 Addition of IMSI to SGSN Context Request
CR A035r2 Improving restoration procedure between SGSN and GGSN
CR A034r1 Correction of used cipher IE
CR A032r6 GPRS Charging enhancements to GTP
CR A045r1 GTP/GTP’ Protocol Type bit
CR A044r1 Introduction of the PDP-type PPP
CR A048 Introduction of the PDP type OSH:IHOSS
CR A052 Clarification of ambiguous/superflous information
CR A054 Timer handling in GTP
CR A055r1 Codepoint for PDP type OSP:IHOSS
CR A062 Removal of changes in PDP context establishment and restoration
CR A063 Mandatory info in MM Context IE
CR A064 APN to be transferred in the PDP context at inter SGSN RA update
CR A065 Consistency on implemented CRs from SMG#28
CR A066 Replacing the V(R) transfer mechanism with the N-PDU number transfer mechanism in routing area update
CR A067 Mandatory SGSN Context Acknowledge message
CR A068 MSISDN in the Create PDP Context request
CR A073r2 on Specification of the MSISDN Information Element in GSM 09.60
CR A079r1 Clarification of GSN Address field
CR A081Clarification of Repeated Information Element Ordering
CR A082r2 Use of 3 Digit MNCs in GTP for R’98
CR A084r1 on Encoding of spare IMSI Digits
CR A090r2 MM Context information coding clarification
CR A091r1 Encoding of IMSI
CR A094 Removal of IHOSS from GTP
CR A095r1 Coding of TI in PDP Context IE
CR A097 Addition of MS Not Reachable Reason to Send Routing Information
Conversion to 3GPP layout
IMSI Encoding Clarification
Re-configure the IEs in the Create PDP Context Request to make it in ascending order
Corrupted figure 20 fixed
Corrupted figures fixed
Clearfication of the term TLLI in SGSN Context Request
Addition of APN-OI to Inter-SGSN RAU
Removing inconsistency in definition of PDP Address length
Enabling control of content served to subscribers based on their location