global title translation

Global Title Translation Siemens

MN2513EU11MN_0001 2006 Siemens AG

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Contents 1 Routing without global title translation 3 2 Routing with global title translation 7 2.1 Why global title translation? 8 2.2 Examples of global title translation 10 3 Global title translation 23 3.1 SCCP calling and called party addresses 24 3.2 Where is global title translation done? 28 3.3 Message flows 30 3.4 Administration of global title translation 34 4 Application examples 51 4.1 Network-internal location update 52 4.2 Mobile terminating call 56 4.3 International location update 60

Global Title Translation

Siemens Global Title Translation


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1 Routing without global title translation



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Link-by-link signaling is always used for traffic channel-oriented connections. In other words, the problem of addressing destination points in an unknown network does not occur with this kind of signaling. However, the problem of network gateways also exists in this case because the addressing in CCS7 is only possible within one network (NAT0/ NAT1/ INAT0). This does not present too many difficulties though, as the messages are evaluated and regenerated at user level (e.g., ISUP) in each switching center the traffic channels pass through. For this reason, at network gateways from e.g. the network NAT0 to the network NAT1, the incoming message from NAT0 is received and evaluated in the standard routing database, CR CPT CR DEST CR ROUTE CR TGRP CR TRUNK regenerated and sent to the signaling point defined using ENTRC7TGREL: DPC= , TGNO=.,NETIND=NAT1. In other words, signaling points that cover network gateways must have an OPC for different signaling networks.



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SIEMENS SIEMENS

SIEMENS SIEMENS

SIEMENS SIEMENS

SIEMENS SIEMENS

Dialing InfoOriginNet

DestinationNet

Dialing Info

ENTRC7TGREL:

DPC=NETIND=

Dialing Info

ENTRC7TGREL:

DPC=NETIND=

Dialing Info

ENTRC7TGREL:

DPC=NETIND=

Dialing Info

ENTRC7TGREL:

DPC=NETIND=

Dialing Info

ENTRC7TGREL:

DPC=NETIND=

Dialing Info

ENTRC7TGREL:

DPC=NETIND=

Signaling

Circuit

Fig. 1 Routing without global title translation



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2 Routing with global title translation



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2.1 Why global title translation? The CCS7 signaling method identifies the destination and the origin of a signaling message by using signaling point codes (SPCs). Since a signaling point code has got 14 bits only, it is too small to address all signaling points worldwide unambiguously. For this reason, signaling point codes are always combined with a network indicator NI which means that a code is only ever valid in one particular signaling network. To facilitate unambiguous global addressing, a unique international address or sender information is necessary. This global address is known as the global title and is sent in the SCCP called- and calling party address of CCS7 messages. Since SPCs are only valid within individual networks, so-called global title translation must be performed at each relevant network gateway. The SCCP performs the global title translation, whereby an internationally unique address (global title) is translated into an SPC and network indicator in order to be transferred to the network border, or to a destination if it is located in the same network. Global title translation is always used if no SPC for the destination is available at all. For example, the HLR has to be identified on the basis of the IMSI or the VLR/MSC on the basis of the VLRISD.



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NAT0 100 NAT0 200

NAT0 200NAT0 100

NAT0 300NAT1 100

NAT1 300NAT0 400

NoSPC

Global Title

DPC & NETIND

Global Title

DPC & NETIND

Global Title

DPC & NETIND

Global Title

DPC & NETIND

Global Title

DPC & NETIND

Global Title

DPC & NETIND

300 NAT0

200 NAT0

300 NAT1

NAT0

NAT1

NAT0

SPC=200NETIND=NAT0

SPC=200NETIND=NAT0

?

Fig. 2 Why global title translation?



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2.2 Examples of global title translation

Location update The visitor location register (VLR) requests the HLR for the subscriber data. The home location register (HLR) is determined by the IMSI (global title). The MCC and the MNC indicate if the HLR is from the home or from a foreign PLMN. The first digits of the MSIN identify the HLR within the PLMN. If the mobile subscriber has changed the VLR area, the HLR cancels the location in the old VLR. The old VLR is determined by the VLRISD (global title), stored in the subscriber's mobility data.

Mobile terminating call The gateway MSC (GMSC) requests routing information from the HLR (interrogation). The HLR is determined by the dialed MSISDN (global title). The CC and NDC indicate if the HLR is from the own or from a foreign PLMN. The first digits of the SN identify the HLR within the PLMN. The HLR then requests the VLR for an MSRN. The VLR is determined by the VLRISD (global title).

Triple request The VLR requests new authentication triples from the HLR. The HLR is determined by the IMSI (global title).

Inter MSC handover The old MSC requests a handover to a new MSC. The new MSC is determined by the MSCID (global title).



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SIEMENS SIEMENS SIEMENS SIEMENS

VLR/MSC HLR

IMSI DPCNETIND

Location Update


VLR/MSC HLR

MSISDN DPCNETIND

Mobile Terminating Call

SIEMENS SIEMENS

VLR/MSC

SRI

PRNDPCNETIND

Location Update


VLR/MSC HLR

DPCNETIND

TripleRequest

Triple Request

SIEMENS SIEMENS

newMSC

SIEMENS SIEMENS

Old MSC

DPCNETIND

HandoverRequest

Handover

VLRISD

MSCID

IMSI

Fig. 3 Examples of global title administration



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2.2.1 Location update with national / international roaming

National roaming For location updates with national roaming, the IMSI is supplied by the mobile station, or, if the location changes, from a known VLR in the new location. The location update must then be sent to the HLR of the subscriber. The IMSI is transferred to the SCCP for this purpose. The SCCP contains the global title database. Using this database, the SCCP translates the IMSI, including the HLRID, to a destination point code and the associated network indicator. Global title translation is not required for the reply from the HLR because the DPC can be used for addressing.



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MTP

SCCP

TCAP

VLRBSSAP

OTHER

INAP EIR MSC HLR

VLR/MSC

MCC/MNC/HLRID


MCC/MNC/HLRID

SPC&NETINDof HLR


MCC/MNC/HLRID

SPC&NETINDof HLR

SIEMENS SIEMENS

DPCNETIND

HLR

Fig. 4 National location update



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C

International roaming For location updates with international roaming, the IMSI is supplied by the mobile station or, if the location changes, from a known VLR in the new location. The location update must then be sent to the HLR in the remote network of the booking subscriber. The IMSI is transferred to the SCCP for this purpose. The SCCP contains the global title database. Using this database, the SCCP translates the IMSI up to the MNC into the destination point code of the gateway to the next network. The IMSI is also transferred as the international address/global title in the SCCP called party address. The IMSI must therefore be changed to an international standard that can be recognized by the PSTN (hybrid IMSI). Global title translation takes place again in that gateway in order to obtain the CCS7 address in the next signaling network. Global title translation is performed for each change in network until the destination network is reached. Generally, translation takes place a last time in the gateway of the destination network, where the DPC and network indicator of the HLR are determined.



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NAT0 100

NAT0 200NAT1 100

MCC/MNC/MSINMCC/MNC

DPC=200 NI=NAT0

MCC/MNC

DPC=200 NI=NAT0NAT0

OriginNet

NAT1

NAT0DestinationNet

NAT1 300INAT0 100

INAT0 300NAT1 100

INAT0

NAT1 300NAT0 100

NAT0 200

NAT1

hybrid IMSI

DPC=300 NI=NAT1

hybrid IMSI

DPC=300 NI=NAT1

Global Title

Global Title

Global Title

Global Title

No Global Title

HLR

MSC/VLR

hybrid IMSI

DPC=200 NI=NAT0

hybrid IMSI

DPC=200 NI=NAT0

hybrid IMSI

DPC=300 NI=INAT0

hybrid IMSI

DPC=300 NI=INAT0

hybrid IMSI

DPC=300 NI=NAT1

hybrid IMSI

DPC=300 NI=NAT1

Fig. 5 Location update with international roaming



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2.2.2 National mobile terminating call The digit translator receives a dialed MSISDN of the own PLMN with the result "interrogation" (TRATYP=MOBINTER). This result leads to a destination with MINMAX on one hand, and to global title translation on the other. Similar to the IMSI in location updates, the MSISDN is translated by global title translation into the CCS7 signaling address of the HLR of the called party. The MAP message Send Routing Information is then sent to the HLR. The mobility data of the called party are read in the HLR in response to the message. Using the VLRISD stored in the HLR, the global title translation function is activated to translate the VLRISD into the CCS7 signaling address of the VLR/MSC of the called party. The request to provide a mobile station roaming number is sent to this address.



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MTP

SCCP

TCAP

VLRBSSAP

OTHER

INAP EIR MSC HLR

VLR/MSC

[CC]/[NDC]/SN

Global Title Translation:

CC/NDC/HLRID

SPC&NETINDof HLR


CC/NDC/HLRID

SPC&NETINDof HLR

SIEMENS SIEMENS

HLR

MTP

SCCP

TCAP

VLRBSSAP

OTHER

INAP EIR MSC HLR

HLRvisited

VLR/MSCof B sub


VLRISD

SPC&NETINDof MSC/VLR


VLRISD

SPC&NETINDof MSC/VLR

Fig. 6 National mobile terminating call



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2.2.3 International mobile terminating call If a foreign MSISDN is received by an MSC, usually no international interrogation is started. The dialed MSISDN is analyzed in the visited MSC and the call is switched as a normal traffic channel connection (e.g., ISUP) to the destination network (usually via PSTN). The call received in the destination network is analyzed in the gateway MSC and interrogation is started. From this point on, the mobile terminating call is handled in the same way as a national mobile terminating call, described before.



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VLR/MSC SIEMENS SIEMENS

Gate-way

SIEMENS SIEMENS

SIEMENS SIEMENS

SIEMENS SIEMENS

Gate-way

SIEMENS SIEMENS

OriginNet

PSTNSwitch

PSTNSwitch

HLR

ISUP

ISUP

ISUP

ISUP

DestinationNet

MAP

PSTNNet

MSISDN


MSISDN

SPC&NETINDof HLR


MSISDN

SPC&NETINDof HLR

Fig. 7 International mobile terminating call



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2.2.4 Mobile terminating call to an own mobile subscriber roaming in a foreign PLMN

In case of mobile terminating calls to a networks own mobile subscriber, currently located in a foreign network, the MSISDN of the called party is received by the calling partys MSC. Since the mobile user belongs to the same network, interrogation is started in the networks own HLR. The VLRISD of the foreign VLR is stored in the HLR as part of the mobility data of the called party. Using global title translation, the VLRISD is translated into the address of the networks own gateway switches and the MAP message Provide Roaming Number is sent there. Since this involves a change in networks, global title translation is again necessary. The VLRISD is translated to the signaling address of the next network node (e.g., to NAT1) and the message is transferred. Global title translation is performed for each change in network until the gateway in the destination network is reached. Generally, translation takes place a last time here because the VLR can be identified from this point by means of the CCS7 signaling address.



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NAT0 100

NAT0 200NAT1 100

MSISDNMSISDN

DPC=300 NI=NAT0

MSISDN

DPC=300 NI=NAT0

NAT0 OriginNet

NAT1

NAT0DestinationNet

NAT1 300INAT0 100

INAT0 300NAT1 100

INAT0

NAT1 300NAT0 100

NAT0 200

NAT1

VLRISD

DPC=300 NI=NAT1

VLRISD

DPC=300 NI=NAT1

VLRISD

DPC=300 NI=INAT0

VLRISD

DPC=300 NI=INAT0

VLRISD

DPC=300 NI=NAT1

VLRISD

DPC=300 NI=NAT1

VLRISD

DPC=200 NI=NAT0

VLRISD

DPC=200 NI=NAT0

Global Title

Global Title

Global Title

Global Title

No Global Title

VLR

VLRISD

DPC=200 NI=NAT0

VLRISD

DPC=200 NI=NAT0

NAT0 300MSCHLR

Fig. 8 Mobile terminating call to an own mobile subscriber roaming in a foreign net



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3 Global title translation



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3.1 SCCP calling and called party addresses The variable mandatory part and optional part fields in the SCCP message contain the called party and calling party addresses. The addresses are used for global addressing of signaling point codes and additionally contain the subsystem number. This number is used for addressing the subsystem in the destination point by the SCCP. The global title is not required in the simplest case (internal network routing) because the routing label of the CCS7 message can be used for addressing. In other words, the subsystem number is adequate as addressing information in this case. The information units of this type of address have the following meaning:

Length indicator (mandatory) The length indicator indicates the amount of the following octets

Address indicator (mandatory): 1. SPC indicator (bit 0)

A "1" indicates that the address contains an SPC A "0" indicates that the address does not contain an SPC

(set to 0 according to GSM recommendation) 2. Subsystem indicator (bit 1)

A "1" indicates that the address contains a subsystem number SSN (set to 1 according to GSM recommendation)

3. Global title indicator (bits 2...5) The global title indicator indicates the content of the address field

0000 no global title included 0100 global title includes translation type, numbering plan, encoding scheme

and nature of address (Global Title Format 4) 4. Routing indicator (bit 6)

Bit 6 of the address indicator octet informs the next SCCP signaling node how SCCP routing has to be performed:

a) A "0" in bit 6 indicates that routing should be based on the global title in the address.

b) A "1" in bit 6 indicates that routing should be based on the DPC in the MTP routing label and the subsystem number SSN in the called party address. (If the point code indicator is set to "1", the SCCP receiver could take the SPC of the SCCP address instead of the MTP-DPC.)

5. Bit 7 of the address indicator octet is designated for national use.



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Subsystem Number Carries the number of the calling/called Subsystem, e.g. HLR, VLR, BSSAP.

(0)(0)(0) (0) (1)(0)(0) (0)

(1) (1) (1)(0)(0) (0) (0)

(0) (0) (0) (0)

SSNIndicator

(1)

SPCIndicator

(0)Global Title Indicator (0)

SSNIndicator

(1)

RoutingIndicator

(1)

notused

(0)SSN (e.g. VLR=7)

Lenght Indicator (2)

Length Indicator is 2 because two more bytes follow.

SPC Indicator is 0 because no SPC is included. Recommended!

SSN Indicator is 1 because SSN is always included in Siemens solution.

Global Title Indicator is 0 because no GT is included. Recommended!

Routing Indicator 1 means Route on OPC/DPC of MTP L3 Routing Label.

Subsystem Number.E.g. HLR=6, VLR=7, MSC=8, EIR=9

Called and Calling Party Address structure if routingis done on OPC/DPC of the MTP L3 Routing Label.Shortest possible length of Address fields!

Fig. 9 Example of called and calling party addresses for net internal use: no GT contained



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Signaling point code SPC (optional, but not necessary for GSM). The SPC identifies the absolute end SPC and, if point code indicator = 1, consists of 14 bits of 2 octets.

Subsystem number (optional, but necessary for GSM) The subsystem number (SSN) identifies an SCCP user function and if subsystem indicator = "1", consists of one octet coded as follows (examples): 1. 11111110= 254 BSSAP (SSID = BSSAP) 2. 00000111= 7 VLR (SSID = MAPVLR) 3. 00000110 = 6 HLR (SSID = MAPHLR) 4. 00001000= 8 MSC (SSID = MAPMSC) 5. 00001001= 9 EIR (SSID = MAPEIR)

Translation type The translation type is a one-octet field that is used to direct the message to the appropriate global title translation function. Thus, it may be possible for the address information to be translated into different values for and different combinations of DPCs, SSNs and GTs. 1. 00000000= 0 TTID=UNKNOWN (mandatory for international

applications) 2. 00000001= 1 TTID=IMSI (not used: in case of international location

update TTID=IMSI has to be converted to UNKNOWN) 3. 00000010= 2 TTID=IMEI According to GSM recommendation, the

translation type should be UNKNOWN

Numbering plan 1. 0000= 0 NP= unknown: not used in international traffic

2. 0010= 1 NP= ISDNTNP (ISDN telephony numbering plan, E.163/E.164). Example: to address a VLR of a foreign PLMN

3. 0110= 6 NP= LMNP (land mobile numbering plan, E.212): not used in intern. traffic

4. 0111= 7 NP= ISDNMNP (ISDN mobile numbering plan, E.214). Example: to send a location update message to an HLR of a foreign PLMN



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Encoding scheme (that information cannot be administered) 1. 0001 = 1 odd number of digits 2. 0010 = 2 even number of digits

Nature of address 1. 0000001= 1 NA = SUBNO (subscriber number) 2. 0000010= 2 reserved for national use 3. 0000011= 3 NA = NATNO (national number) 4. 0000100= 4 NA = INTNO (international number)

(0)(0)(0) (0) (1)(0)(1) (1)

notused

(0) (0) (0) (1)(0) (0) (0) (1)

(0)(0)(0)(0)(0)(0)(0)(0)

(1) (1) (0)(0)(0) (0) (0)

(0) (1) (0) (0)

SSNIndicator

(1)

SPCIndicator

(0)Global Title Indicator (Type 4)

SSNIndicator

(1)

RoutingIndicator

(0)

notused

(0)SSN (e.g. HLR=6)

TTID (e.g. UNKNOWN)

NP (e.g. ISDNTNP) Encoding Scheme (e.g. odd)

(0)(0)(1)(0)(0)(0)(0)NA (e.g. INTNO)

(0) (1) (0) (0)(1) (0) (0) (1)GT digit 2 (e.g. 9) GT digit 1 (e.g. 4)

(0) (0) (0) (1)(0) (1) (1) (1)GT digit 4 (e.g. 7) GT digit 3 (e.g. 1)

(0) (1) (1) (0)(1) (1) (1) (1)GT digit n+1 (e.g. Filler) GT digit n (e.g. 6)

Lenght Indicator (e.g. 11)...

Length Indicator depends on number of Global Title Digits.

SPC Indicator is 0 because no SPC is included. Recommended!

SSN Indicator is 1 because SSN is always included in Siemens solution.

Global Title Indicator is 4 because GT of Type 4 is included.

Routing Indicator 0 means Route on Global Title.

Position and structure of SPC if it is included. NOT RECOMMENDED!

Called and Calling Party Address structure if routingis done on Global Title Translation.Length depends on number of Global Title digits!

notused

notused

(SPC bits 0-7)

(SPC bits 8-14)

Subsystem Number.E.g. HLR=6, VLR=7, MSC=8, EIR=9

Translator Type Identification. 0=UNKNOWN, 1=IMSI, 17=IEESS.

Encoding Scheme. 1=odd number of GT digits, 2=even number of digits.

Numbering Plan. 1=ISDNTNP, 6=LMNP, 7=ISDNMNP.

Nature of Address. 3=National number, 4=International Number

GT digits. Last digit is a filler (HF) if Encoding Scheme is odd.

Fig. 10 Example of called/calling party addresses for international use: GT contained



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3.2 Where is global title translation done? One (or more) of the main processors for applications (MP:AP) has to be determined to be responsible for GTT. The functions of this "MP:GTT" is not exclusively available to the shelf in which it is located but to the whole node. The parameters Load type and Load model determine the software functions of the MP, since the HW is the same for all MP:AP. For "MP:GTT" the Load models SLTSGTR (recommended use) or SLTSGTR1/2 may be used in combination with the Load type TSLT0001.

Load Type Load Model Meaning TSLT0001 SLTSGTR MP for SCCP global title translation only

(recommended)

TSLT0001 SLTSGTR1/2 MP for SCCP global title translation and MTP L2/L3 functions



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Create MP for Global Title Translation

CRMP: MP = ,Load type = TSLT0001,Load model= ,Rack= ,Shelf= ,Pitch= ,Board type= ,Statistics= FALSE,[Alarm profile MP= ,][Alarm profile MP Mpu= ];

Fig. 11 Creating a main processor for global title translation



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3.3 Message flows

3.3.1 Signaling end point Messages from a LTG, for which global title translation has to be done are forwarded to the MP responsible for GTT automatically. After GTT, the MSU with the new DPC/NETIND in it's routing label leaves towards the MP:SLT that will do message routing by evaluating the DPC and allocating a linkset and a link via which the message leaves the NE. Signaling messages, coming in from another NE, will be received by an MP:SLT and also routed to the MP responsible for GTT. After GTT the message will be passed on to the subsystem responsible for evaluating the message content. This may be located in the CP or in a GP of the LTGs. (Example: The switch receiving such a message is a Gateway AND the final receiver). The SSNC-internal path of the MSU is the same, no matter via which kind of link it was received (64kbit/s link or high speed link).



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MP/SM

MP/SLT

MP/GTT

LIC

LIC

MP/OAM

SC

ASN

SSNC

MB D

SS7-Links 64kbit/sorHS-Links 2Mbit/s

SS7-Links 64kbit/s,trunks

CP113CCP113C

LTG

LTGDLU

SNSN

LTG

LTG

MP/STAT

Fig. 12 Signaling end point, incoming MSU

MP/SM

MP/SLT

MP/GTT

LIC

LIC

MP/OAM

SC

ASN

SSNC

MB D



CP113CCP113C

LTG

LTGDLU

SNSN

LTG

LTG

MP/STAT

Fig. 13 Signaling end point, outgoing MSU



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3.3.2 Signaling relay point Pure signaling transfer points (STP) do not care about the message content. They forward an MSU because of the DPC in it's routing label and don't do global title translation. Signaling relay points (SRP) also don't care about the message content, but they do a global title translation and forward the message, depending on the result of that GTT (typical application: international gateway exchange for signaling traffic). Incoming MSUs will be received by an MP:SLT, forwarded to the MP responsible for GTT and, depending on the result of the GTT, forwarded to another MP:SLT that provides the connection to the link, leading to the DPC found in GTT. The SSNC-internal path of the MSU is the same, no matter via which kind of link it was received (64kbit/s link or high speed link).



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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MP/SM

MP/SLT

MP/SLT

LIC

LIC

MP/OAM

SC

ASN

SSNC

MB D



CP113CCP113C

LTG

LTGDLU

SNSN

LTG

LTG

MP/STAT

MP/GTT

Fig. 14 Signaling relay point with GTT



34

3.4 Administration of global title translation The global title translation database should be created in the following sequence: 1. CR SPLNKLOC / SPLNKREM:

General data about the own SCCP or the SCCP in the destination signaling points (see chapter about SCCP administration).

2. CR SPSSN: Links a subsystem ID to a subsystem number for a local SCCP linkage (see chapter about SCCP administration).

3. CR SPAPLOC / SPAPREM: Creation of subsystems control data in the own or the destination signaling point (see chapter about SCCP administration).

4. CR SPCLGPA: Creation of Calling Party addresses for local subsystems which use message transfer via Global Title Routing

5. CR SPTT: Linking an SCCP-specific translation type id to a translation type number that will be used in the SCCP messages.

6. CR SPENS/SPRNS: List of possible routes, used to reach a local or remote SCCP linkage with or without further GTT.

7. CR SPGTTRL: Combinations of format parameters that describe the global title digits.

8. CR SPGTCRUL: List of instructions to modify the global title that leaves the NE as new SCCP called party address (if required).

9. CR SPGTRUL: Definition of how to find the result of global title translation.



35

Relay Node Set RetranslationEnd Point Entity

Set without SSN

Remote SCCPLinkage

SCCPLinkage

SCCP cdPA

OPC DPC NI

Incoming MSU

Global Title Conversion Rule

Global Title Rule

Global Title Translator

SCCP cdPA

OPC DPC NI

Outgoing MSU

Relay Node Set RetranslationEnd Point Entity

Set without SSN

Remote SCCPLinkage

Fig. 15 Global title translation



36

3.4.1 Administration of the calling party address For each local SCCP subsystem which may use message routing via GT, a calling party address (cgPA) has to be defined, containing the global title of the NE (E.164) and the subsystem number. It has the same data fields as the SCCP called party address. This cgPA is included in outgoing SCCP messages to other signaling networks and contains enough information to identify the originating signaling point and/or the SCCP service access point unambiguously. A cgPA may contain a global title, e.g. for international signaling. A global title is usually not required in an SCCP calling party address for network internal signaling, since in that case all necessary information for routing an acknowledgement can be obtained from the routing label. The 'CLGPA type indicator' defines the routing preference, i.e. whether a GT shall be contained in the cgPA field of an outgoing MSU or not.



37

Create SCCP calling party address

CRSPCLGPA: SPCLGPA name = , [SPCLGPA id = ,] SPAPLOC name / ID = , SPLNKLOC name / ID = , GT Address Info = , TTID = Unknown, NP = ISDN Telephone Numbering Plan, NA = International Nr. , CLGPA Type Indicator = Programmed , [Include SPC = False,] [Include GT = False];

Fig. 16 SCCP calling party address

SIEMENS SIEMENS

SIEMENS SIEMENS

SIEMENS SIEMENS

HLR

VLR

IGE

foreignPLMN

SIEMENS SIEMENS

RI = 1:

cgPA =

onlySSN

Update_

Locatio

n

RI = 0:cgPA = Full Global

TitleUpdate_Location

LocationUpdate

HLR

CRSPCLGPA:CLGPA Type Ind=Programmed, ...

Fig. 17 Effect of parameter 'CLGPA Type Indicator'



38

3.4.2 SCCP end node entity sets The SCCP End Node Entity Sets describe a local or remote SCCP linkage as result of global title translation in case the final signaling end point (i.e. where the message content is evaluated) can be determined in the own node. In these cases, no further GTT is necessary (RI=1) and the global title will be removed from the called party address automatically. A primary and, optionally, a second destination are provided that may be operated in a loadsharing mode, described by the 'Sharing Mode' (only one of them may be a local SCCP). Both destinations must exist and must have been created in the same signaling network. The 'Sharing Mode' parameter has the following meanings:

Sharing Mode Primary 1 Primary 2 Dupli Load Shared 50% 50%

Dupli Dominant 100% standby

Solitary 100% not entered

TIP Sharing mode = 'Dupli Replacement' can also be found in the selection lists of the switch commander but is not supported by the SCCP.



39

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Create SCCP End Node Entity Set without Subsystem Number

CRSPENS: SPENS Name = ,Primary 1 Name = ,[Primary 2 Name = ,]Sharing Mode = ;

Fig. 18 End node set without SSN



40

3.4.3 SCCP relay node entity sets The SCCP Relay Node Entity Sets describe a remote SCCP linkage as result of global title translation in case the final signaling end point can not be determined in the own node. In this case, a further GTT is necessary in these SCCPs (RI=0). Two primary and two backup SCCP Linkages may be defined. At least 'Primary 1 ID/Name' must be entered. The loadsharing mode between the entered SCCPs is assigned implicitly without extra parameter. The optional 'SSID' parameter allows to set the subsystem number in the outgoing MSU after global title translation if routing is done on global title to a relay node. This parameter should not be used! Implicit loadsharing mode:

SCCP linkage combinations:

Primary 1 load

Backup 1 load

Primary 2 load

Backup 2 load

Primary 1 100%

Primary 1/Primary 2 50% 50%

Primary 1/Backup 1 100% standby for Primary 1

Primary 1/Backup 1/ Primary 2/Backup 2

50% standby for Primary 1

50% standby for Primary 2



41

Create SCCP Relay Node Entity Set

CRSPRNS: SPRNS Name = ,Primary 1 Name = ,[Primary 2 Name = ,][Backup 1 Name = ,][Backup 2 Name = ,][SSID = ];

Fig. 19 Relay node entity set

Primary1:active

Backup1:standby

OPCPrimary1:active

Primary2:active

50 : 50

Primary1:active

Primary2:active

Backup2:standby

Backup1:standby 50 : 50

OPC

OPC

Fig. 20 Loadsharing models for relay node entity sets



42

3.4.4 Global title translator The global title translator specifies the entry requirement for global title translation by providing the format parameters for each possible global title as a combination of Translation Type ID (TTID), Numbering Plan (NP) and Nature of Address (NA). In other words: it tells the SCCP how to interpret the global title digits. This combination must be unique. The 'Global Title Translation Type attribute' represents the translation type, which is a pure SCCP concept. It is part of the global title that indicates the specific use of the global title address information. In other words, it is the key information that differentiates between the use of identical NP/NA/GT- digit combinations. This global title translation has to be converted into a Translation Type Number (TTN) by means of the task CRSPTT.



43

SCCP Global Title Translator

CRSPGTTRL: SPGTTRL Name = ,[SPGTTRL Id = ,]TTID = ,NP = ,NA = ;

Fig. 21 SCCP global title translator

NATNOISDNTNPIEESSCCBS National Number

INTNOISDNTNPIEESSCCBS International Number

NATNOISDNTNPUNKNOWNNational Telephone Number

INTNOISDNTNPUNKNOWNInternational Telephone Number

INTNOISDNMNPUNKNOWNHybrid-IMSI

INTNOLMNPIMSIIMSI

NANPTTID

GT SupplementsGT Number Type

Fig. 22 Examples of format parameters



44

3.4.5 Global title conversion rule The conversion rule for the global title digits contains an ordered list of instructions specifying to insert, delete, replace, or take-over digits or supplements in the old called party address to produce a new one. This new called party address will not be processed again in the own node but will be part of the outgoing MSU. Conversion operations to be defined in a global title conversion rule are:

Operation Meaning + Digits after the '+' sign are inserted at the respective position

R Digits after the 'R' sign replace the original digits at the respective position

X The original digit remains at the respective position (one 'X' per digit)

. The original digit is deleted (one '.' per digit) S Stop converting immediately

T Copy the remaining characters, and then stop

Example: (see next page) An IMSI of a roaming subscriber is being received in a VLR during location update and used as global title in the called party address of the 'Update_Location' message to the subscriber's HLR. Since that global title is not in accordance with the international standard for routing based on global title, it has to be converted into a 'hybrid IMSI'. Whether this conversion is done in the VLR immediately or in a gateway, just before the message leaves the own PLMN, is up to the operator.

IMSI 'hybrid IMSI' MCC - MNC MSIN CC - NDC MSIN

e.g.: 262 - 02 - 1234567890 e.g.: 49 - 172 - 1234567890

TTID=IMSI TTID=UNKNOWN

NP=LMNP NP=ISDNMNP

NA=INTNO NA=INTNO



45

Create SCCP Global Title Conversion Rule

CRSPGTCRUL: SPGTCRUL Name = , Addr. Info Conv. Rule = , New TTID = , New NP = , New NA = ;

Fig. 23 SCCP global title conversion rule

SCCP cdPA

OPC DPC NI

Incoming MSU

SCCP cdPA

OPC DPC NI

Outgoing MSU

IMSI = 262 - 02 - 1234567890

hybrid-IMSI = 49 - 172 - 1234567890

CR SPGTCRUL:

SPGTCRUL Name= .............................................................

Addr. Info Conv. Rule= .......................................................

New TTID= .................................................................................

New NP= .....................................................................................

New NA= .....................................................................................

Fig. 24 GT conversion rule for location updates



46

3.4.6 Cancel a Global Title in the cdPA A special version of a conversion rule is usually used to cancel a GT address in the CALLED Party Address. This can be done e.g. in the last Gateway, because the final destination is known there so no further GTT is necessary, or in the very first switch, when no routing on GT is used for an outgoing message. The benefit will be that the outgoing message is shortened and is therefore transmitted more efficiently. The creation of this rule is very simple. The name is free, but CANGT is a very common name. For the Addr. Info Conv. Rule parameter just enter the character "S", which means "Stop conversion and delete all remaining digits and supplements". All other parameters of the task are not used in this case.

TIP As this can be done for the CALLED PARTY only, the CALLING PARTY address will remain unchanged in the outgoing message which is routed on GT! But the CALLING PARTY address will also be deleted, if routing on OPC/DPC (SPENS) is already used in the first switch and the parameter CLGPA Type Indicator = Programmed of the task CRSPCLGPA (see 3.4.1) is used.

The following rules should be noticed: 1. Message CREATED in a switch and sent with routing on OPC/DPC (SPENS):

a) Conversion Rule to delete CALLED Party address necessary (CANGT) b) CALLING Party address automatically deleted ("Programmed")

2. Message CREATED in a switch and sent with routing on GTT (SPRNS): a) No Conversion Rule to delete CALLED Party address allowed b) CALLING Party address automatically included ("Programmed")

3. Message TRANSFERRED in a switch with routing on OPC/DPC (SPENS): Switch is just STP so doesn't touch the SCCP addresses anyway

4. Message TRANSFERRED in a switch with routing on GTT (Gateway/SRP): a) Conversion Rule to delete CALLED Party address only allowed if switch is the

VERY LAST Gateway/SRP to the final receiver, so change to routing on OPC/DPC (SPENS)

b) CALLING Party address is still included, because the message was not created there (so "Programmed" is not relevant) and the incoming message to be transferred already contained a CALLING Party address



47

Create SCCP Global Title Conversion Rule to cancel GT in cdPA

CRSPGTCRUL: SPGTCRUL Name = CANGT, Addr. Info Conv. Rule = S,

Fig. 25 Special Conversion Rule to cancel a GT in the cdPA

SIEMENS SIEMENS

SIEMENS SIEMENS

SIEMENS SIEMENS

Destination

Origin

STPCRSPCLGPA:CLGPA Type Ind=Programmed,...;CRSPGTRUL:GTCRUL Name=CANGT,SPENS Name=,...;

Routing on OPC/DPC:cdPA = cancelled

cgPA = not included

Does not touchthe SCCPaddresses

Fig. 26 Example for CANGT with routing on OPC/DPC

foreignPLMN

SIEMENS SIEMENS

Rout

ingon

GTT

:

Full G

lobal

Title

Destination

SIEMENS SIEMENS

Last Gateway

SIEMENS SIEMENS

Gateway

ownPLMN

Routing on GTT:

Full Global Title Rout

ingon

OPC

/DPC

:

CgPA

includ

ed!

CdPA

canc

elled

!

CANGT todelete cdPA

SIEMENS SIEMENS

Origin

Fig. 27 Example for CANGT with routing on GTT



48

3.4.7 Global title rule The GT-Rule contains matching attributes ('Global Title Address Info' and 'Global Title Translator') used to select the right GT-Rule as well as attributes that allow translation of a global title. The SPENS Name points to a SCCP Entity Set with a LOCAL or REMOTE Sccp linkage. In this case, no further GTT will be performed (RI=1) because the final destination signaling point can be determined in the own node. The global title will NOT automatically be canceled from the SCCP called party address, so use the CANGT conversion rule described before to keep the outgoing message as short as possible! The SPRNS Name points to a relay node entity set, where another GTT has to be performed (RI=0) because the final destination signaling point can't be determined in the own node. In this case, the global title can not be canceled from the SCCP called party address. Global title retranslation can be invoked by means of SPGTT Rule Reference Name and Resume At Digit parameters which allow the selection of another GT Rule. Include SPC indicates whether or not the SPC as the result of GTT shall additionally be included in the SCCP called party address field of the outgoing message. NOT RECOMMENDED! SPGTCRUL is used to modify the address and address indicator fields in the called party address of outgoing messages (e.g. IMSI->hybrid IMSI or CANGT). Traffic Type provides data for traffic measurements by allowing to analyze the cdPA without the need to analyze all possible combinations of global title digits. Possible values are: 'Local', 'Nat. Own', 'Nat. Foreign' or International'.



49

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Create SCCP Global Title Rule

CRSPGTRUL: SPGTRUL Name = , SPGTTRL Name = , [SPGTCRUL Name = ,] GT Address Info = , [SPENS Name =,] [SPRNS Name = ,] [SPGTT Rule Reference Name = ,] [Resume At Digit = ,] [Include SPC = ,] [Traffic Type = ,]

Fig. 28 SCCP global title rule



50



51

4 Application examples



52

4.1 Network-internal location update VLR and HLR within the same node An own mobile subscriber requests a location update in a VLR that is located in the same D900 as his HLR (i.e. they share the same message transfer part and the same SCCP).

SIEMENS SIEMENS

MSC/VLR/HLR

SP 100

Locationupdate

IMSI=262 02 42 12345678

VLRISD=49 172 4200097

HLRISD=49 172 4200096

Fig. 29 Node internal location update



53

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Remote SCCP Linkage

Global Title Conversion RuleGlobal Title Conversion Rule

Local Access Point

Relay Point End Point with SSN

OPC NI+DPCSCCP cdPA

incoming MSU

GT TranslatorGT Translator

GT RuleGT Rule

End Point without SSN

Remote Access PointRemote Access Point


Local SCCP Linkage

OPCSCCP cdPA

outgoing MSU

CRSPGTTRL:

SPGTTRL Name=TTID=NP=NA=

CRSPGTRUL:

SPGTRUL Name=SPGTTRL Name=GT Adr Info=SPENS Name=SPENSSSN Name=SPRNS Name=SPGTCRUL Name=SPGTT Rule Ref Name=Resume at Digit=Include SPC=Traffic Type=

CRSPENS:

SPENS Name=Prim1 Name=Prim2 Name=Sharing Mode=

CRSPAPREM:

SPAPREM Name=SPLNKREM Name=SSID=

CRSPGTCRUL:

SPGTCRUL Name=Addr Info Cov Rule=New TTID=New NP=New NA=

CRSPLNKLOC:

SPLNKLOC Name=Net Name=...

GTDIG=OPC=DPC=SSID=NI=RI=

Global Title:GTDIG=SSID=

NI+DPC

cgPA:

cgPA:

Fig. 30 GTT database



54

HLR and VLR in different nodes An own mobile subscriber registers with a VLR inside his home network and, as a result, causes an 'Update_Location' message, sent from VLR to his HLR.

SIEMENS SIEMENS

MSC/VLR

SP 100

SIEMENS SIEMENS

HLR

SP 200

Locationupdate

IMSI=262 02 4112345678

VLRISDN=49 172 4200097

HLRISDN=49 172 4100096

Fig. 31 Location update in HPLMN



55

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Local Access Point


OPC NI+DPCSCCP cdPA

incoming MSU


GT RuleGT Rule




OPCSCCP cdPA

outgoing MSU

CRSPGTTRL:


CRSPGTRUL:

SPGTRUL Name=SPGTTRL Name=GT Adr Info=SPENS Name=SPENSSSN Name=SPRNS Name=SPGTCRUL Name=SPGTT Rule Ref Name= Resume at Digit=Include SPC=Traffic Type=

CRSPENS:


CRSPAPREM:


CRSPGTCRUL:


GTDIG=OPC=DPC=NI=RI=


NI+DPC

cgPA:

cgPA: Local SCCP LinkageRemote SCCP Linkage

CRSPLNKREM:

SPLNKREM Name=Net Name=DPC=Ass. Con. Section=

Fig. 32 GTT database



56

4.2 Mobile terminating call Interrogating the HLR A mobile subscriber dials the MSISDN of the subscriber from the previous section. The MSC of the A-subscriber send the MAP message 'Send_Routing_Info' to the B subscriber's HLR.

SIEMENS SIEMENS

MSC/VLR

SP 300

SIEMENS SIEMENS

HLR

SP 200

Send Routing Info

SIEMENS SIEMENS

MSC/VLR

SP 100

ProvideRoamingNumber

MSISDN=01724112345

HLRISDN=491724100096

VLRISDN=491724200097

Fig. 33 Mobile terminating call



57

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Local Access Point


OPC NI+DPCSCCP cdPA

incoming MSU


GT RuleGT Rule




OPCSCCP cdPA

outgoing MSU

CRSPGTTRL:


CRSPGTRUL:


CRSPENS:


CRSPAPREM:


CRSPGTCRUL:


GTDIG=OPC=DPC=NI=RI=


NI+DPC

cgPA:

cgPA: Local SCCP LinkageRemote SCCP Linkage

CRSPLNKREM:

SPLNKREM Name=Net Name=DPC=Ass. Con. Section=

Fig. 34 GTT database in A-MSC



58

Requesting an MSRN Due to the VLRISDN, found in the mobility data of the B-subscriber, the HLR requests an MSRN by sending 'Provide_Roaming_Number' to the visited MSC/VLR of the B-subscriber.

SIEMENS SIEMENS

MSC/VLR

SP 300

SIEMENS SIEMENS

HLR

SP 200

Send Routing Info

SIEMENS SIEMENS

MSC/VLR

SP 100

ProvideRoamingNumber

MSISDN

VLRISDN=491724200097

HLRISDN=491724100096

Fig. 35 Mobile terminating call



59

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


Local Access Point


OPC NI+DPCSCCP cdPA

incoming MSU


GT RuleGT Rule




OPCSCCP cdPA

outgoing MSU

CRSPGTTRL:


CRSPGTRUL:


CRSPENS:


CRSPAPREM:


CRSPGTCRUL:

SPGTCRUL Name=Addr Info Cov Rule=New TTID

global title translation

Documents

siemens ag

unambiguous global addressing

network nat1

unknown network

problem of network gateways

network nat0 nat1 inat0

network indicator ni

party address of ccs7