TK155 ITU .pdf

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TK155 EAGLE STP Global Title TransactionITU

Date issued November 2007Document reference & release version

TK155 v5.0

These presentation materials describe Tekelec's present plans to develop and make available to its customers certain products, features and functionality. Tekelec is only obligated to provide those deliverables specifically included in a written agreement signed by Tekelec and customer.

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Tekelec Confidential 07 | 2

Agenda

This class is intended to provide you with a full explanation of Global Title Translation in the Eagle STP

Course Outline Agenda includes the following sections: MTP3 & SCCP Routing GTT definition GTT example GTT configuration

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MTP3 & SCCP Routing

4Notes


Routing

There are 2 levels of routing in SS7 nodes, which are used depending on the type of message (MSU) :

MTP3 routing : Used mainly by ISUP messages SCCP routing : Used mainly by MAP and INAP messages

SCCP routing also uses MTP3 routing. Together they provide a complete routing solution for SS7 exchanges

SS7 stands for Signaling System 7

MSU stands for Message Signal Unit

MTP3 stands for Message Transfert Part level 3

SCCP stands for Signaling Connection and Control Part

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MTP3 Routing

An ISUP MSU uses MTP3 routing OPC and DPC are sufficient information to enable the call to be routed to

the next node, and to set up and manage an ISUP call

SSP

DPC: 4000 OPC: 1000

STP

1000

2000 4000

DPC: 4000 OPC: 1000

SSP

ISUP stands for ISdn User Part

OPC stands for Originating Point Code

DPC stands for Destination Point Code

SSP stands for Service Switching Point

STP stands for Signaling Tranfert Point

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SSN and MTP3 Routing

An SSN (Sub System Number) is a specific application available on a node

If this node is an SCP, an SSN is used to retrieve some information from the database associated with this application

MTP3 routing is not able to route to an SSN or a database

SSP SCP

SSN5

DPC: 3000 OPC: 1000

STP

SSN253

SSN251

1000

2000 3000

DPC: 3000 OPC: 1000

SSN stands for SubSystem Number

SCP stands for Service Control Point

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SCCP Routing

SCCP routing is used each time an application on a node needs to access a database

Examples of SCCP routing: Toll-free numbers: To request the database controlling Toll-free numbers to

find the true number associated them, and thus to enable the call to be setup

Check the credit of prepaid numbers: To request that the database of prepaid numbers, checks on available credit before the call is setup

For MAP operations such as Location Update or Forward Short Message: To request the HLR to retrieve some information about a subscriber

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Example of SCCP routing: Toll-free number

The called number is used for the SCCP routing (GTA) SCCP routing also uses the SSN value to reach the database to request

Caller dials: 08003456789

SSP SCP

SSN5

DPC: 2000 OPC: 1000GTA: 0800345

STP

SSN253

SSN251

1000

2000 3000

DPC: 3000 OPC: 2000SSN : 253

GTA stands for Global Title Address

9Notes


Global Title Translation

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Notes


Global Title Translation (GTT)

SCCP uses a process called Global Title Translation to convert a GTA to a Point Code (and an SSN if possible, and if required) it uses thisinformation to instruct MTP3 on where to route messages

Basically, GTT analyses the CDPA from the SCCP field of the MSU and compares it with its GTT tables to find a Point Code (and an SSN if possible, and if required) of the next node

There are 2 types of GTT: Intermediate GTT : The point code and the SSN of the final node are not

known

Final GTT : The point code and the SSN of the final node are known

CDPA stands for CalleD Party Address

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Notes


Example of the 2 types of GTT

SSP SCP SSN5STP

SSN253

SSN251


DPC: 1500 OPC: 1000GTA: 0800345

DPC: 3000 OPC: 2000SSN : 253

DPC: 2000 OPC: 1500GTA: 0800345

2000 30001500

1000

Final GTT

Intermediate GTT

STP

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Notes


MTP3 & SCCP fields of the MSU

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Notes


Fields read for GTT in the MSU

MTP2 FieldsDPC SI

MTP3 FieldsCDPA

SCCP FieldsTCAP FieldsINAP or MAP Fields

TRANSMISSION DIRECTION

Used to indicate the type of MSU

Used to show if the MSU is for this STP or not

Used to extract SCCP parameters as GTA

SI stands for Service Indicator: SI=3 means the MSU is an SCCP MSU SI=5 means the MSU is an ISUP MSU

If the DPC is not the Point Code of the Eagle STP, the MSU is just MTP3 routed

If the SI=3 and the DPC is the Point Code of the Eagle STP, the CDPA is parsed to extract the required information to perform GTT

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Notes


Structure of the CDPA

First Octet of the CDPA gives some information regarding the content of the following octets: This is the Address Indicator

8 7 6 5 4 3 2 1

NI RI GTI SSN PC

Used to show if a Point Code is present in the CDPA

Used to show if a SSN is present in the CDPA

Used to show which field of the CDPA extract to perform GTT

Used to indicate if the MSU needs further GTT or not

Not used in ITU

Bit 1: Indicate if the PC is present or not in the CDPA0 - point code is not included1 - point code is included

Bit 2: Indicate if the SSN is present or not in the CDPA0 - subsystem number is not included1 - subsystem number is included

Bits 3 thru 6 are the global title indicator (GTI). 3 possibles values are supported by the Eagle STP:0 - no global title included2 - global title includes translation type only4 - global title includes translation type, numbering plan, encoding scheme, nature of address

Bit 7: Indicates if subsequent GT translations are required 0 Called also GT, indicates that a subsequent translation must be performed1 Called also SSN, indicates that no further translations are required

Bit 8: Reserved and not used in ITU

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Notes


Structure of the CDPA

Following octets of the CDPA

8 7 6 5 4 3 2 1

SSN (if present)TT

NPNAI

Digit 1

ES

Digit 2Digit 3Digit 4Digit 5Digit 6Digit 7Digit 8

PC (if present)

GTA

In ITU the PC is rarely present in the CDPA also the second octet of the CDPA is the SSN if it is present

SSN is the value of the application used to query its associated database

TT is the Translation Type. Mostly equal to 0 in ITU

NP is the Numbering Plan of the following GTA in the CDPA. Could be E164, E214 or E212

ES is the Encoding Sheme of the following GTA in the CDPA. Always equal to BCD encoding in ITU

NAI is the Nature Address Indicator of the following GTA in the CDPA. Could be Subscriber, National or International

GTA part contains the dialed number. The BCD encoding is used. That means that one octet contains 2 digits of the number

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Notes


NI RI GTI=4 SSN PC

Global Title Indicator (GTI)

2 configurations are possible in ITU Depending on the value of the GTI, different fields are extracted to

perform GTT

SSNTT

NPNAI

Digit 1

ES


NI RI GTI=2 SSN PC

SSNTT

NPNAI

Digit 1

ES


The GTI=4 is the most used one in ITU because in ITU TT=0 in most of case also other field need to be extracted to interpret the GTA

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Notes


GTT Tables

Extracted fields from CDPA are used to lookup the corresponding table to translate the GTA to DPC (and SSN if possible and if required)

GTI=4, TT=0, NAI=NATL, NP=E164, ES=BCD

Table1GTA:06070000 DPC: 5000 RI:gtGTA:06071111 DPC: 6000 RI:gt

GTI=4, TT=0, NAI=INTL, NP=E164, ES=BCD

Table2GTA:336070000 DPC: 111 RI:gtGTA:336071111 DPC: 222 RI:gt

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Notes


Example of GTT

SSP


1500

1000

STP

MSU sent by the SSP to the STP

SSN=253TT=0

NP=E164NAI=NATL

Digit 1=0

ES=BCD

Digit 2=8Digit 3=0Digit 4=0Digit 5=3Digit 6=4Digit 7=5Digit 8=0

NI=0 RI=0 GTI=4 SSN=1 PC=0

DPC=1500 NI=2 SI=3MTP3 Fields

CDPASCCP Fields


The SSP doesnt have in its MTP3 routing table another SSP or Switch where to route this call

The SSP must build an INAP query and uses its SCCP routing table to send it to the STP with the Point Code 1500

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Notes


Example of GTT

The STP with the PC 1500 performs GTT depending on the information extracted from the incoming MSU

This information is used to lookup the corresponding table to translate the GTA to a DPC (SSN is already known in this example and does not need to be looked up)

1500

STP


Table1GTA:0800345 DPC: 2000 RI:gt

GTT is donein the STP

As RI=gt that mean this STP perform Intermediate GTT

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Notes


Example of GTT

1500

STP

MSU sent by the STP to the next STP NI=0 RI=0 GTI=4 SSN=1 PC=0

SSN=253TT=0

NP=E164NAI=NATL

Digit 1=0

ES=BCD



CDPASCCP Fields


2000

STP

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Notes


Example of GTT

The STP with the PC 2000 performs GTT depending on the information extracted from the incoming MSU

This information is used to lookup the corresponding table to translate the GTA to a DPC (SSN is already know in this example and does not need to be looked up)

2000

STP


Table1GTA:0800345 DPC: 3000 RI:ssn

GTT isdone in the STP

Ri=ssn means this STP perform Final GTT

As the SSN is already into the MSU, this STP dont have to fill this information into the MSU to perform Final GTT

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Notes


Example of GTT

2000

STP

MSU sent by the STP to the next STP

SSN=253TT=0

NP=E164NAI=NATL

Digit 1=0

ES=BCD




CDPASCCP Fields


SCPSSN253

3000

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Notes


CGPA

To be enable it to receive a response from the requested database the originating node (SSP in the previous example) inserts its GTA address in the CGPA of the SCCP field of the MSU

This means all nodes are identified by a PC and an SCCP address (called node ID)

The structure of the CGPA is exactly the same as the CDPA

Normally the Node Initiating the query inserts the CGPA of the originating SSN into the SSN field of the CGPA

To route the response, the final SCP node switches the CDPA & CGPA and uses SCCP routing to respond to the originating node

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Notes


DPC=1500 NI=2 SI=3


CGPA: SSP builds an INAP query

SSP

1500

1000

STP

250

MSU sent by the SSP to the next STP

SSN=250TT=0

NP=E164NAI=NATL

Digit 1=1

ES=BCD


MTP3 FieldsCGPA

SCCP Fields


12345678

When an SSP build an INAP query an SSN on the SSP is specified

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Notes


DPC=1500 NI=2 SI=3


CGPA: MSC/VLR sends an Update Location

MSC

1500

1100

STP

7

MSU sent by the MSC/VLR to the next STP SSN=7

TT=0NP=E164

NAI=NATLDigit 1=1

ES=BCD


MTP3 FieldsCGPA

SCCP Fields


12345666

When an MSC/VLR send an Update Location, the SSN of the VLF (7) is put into the SSN field of the CGPA of the MSU

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Notes


MTP3 & SCCP routing within the Eagle STP

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Notes


MTP3 Routing in the Eagle STP

SS7 Card 1201

Port A or B

incoming ISUP MSU

Discrimination

Level 2

MTP Routing Routing

Port A or B

IMT Bus

outgoing ISUP MSU

Step 1

Step 2

Step 3

SS7 Card 1301

In the SS7 card 1201 Step1: MTP2 error checking is performed to check the MSU is not corrupted Step2: Discrimination means extract the SI field from the MTP3 portion of the MSU to identify the type of theincoming MSU. In this example SI=5 means ISUP MSU. That means this MSU just need to be MTP3 routed Step3: The SS7 card has a copy in her memory of the routing table stored in the TDMs. With the DPC of the MSU, the SS7 card is so able to route the MSU to the next node. A link has been chosen and the card where this link isplugged is also identified

In the SS7 card 1301: The MSU is just routed on the chosen link

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Notes


SCCP Routing in the Eagle STP

SS7 Card 1201

Port A or B

incoming SCCP MSU

Discrimination

Level 2

Distribution

routing table

linkset table

slk table

Routing

Port A or B

IMT Bus

outgoing SCCP MSU

GTT Tables

DSM-VSCCP 1203

Step 1

Step 2

Step 3

Step 7

Step 6

Step 5

Step 4

SS7 Card 1301

In the SS7 card 1201 Step1: MTP2 error checking is performed to check the MSU is not corrupted Step2: Discrimination means extract the SI field from the MTP3 portion of the MSU to identify the type of theincoming MSU. In this example SI=3 means SCCP MSU. That means this MSU must be translated by using GTT to find the PC of the next node Step3: The SS7 card use the method of Ticket Voucher Group to find a DSM card available to perform this GTT and send her the MSU

In the DSM card 1203 Step4: GTT is performed Step5: The DSM card has a copy in her memory of the routing table stored in the TDMs. With the translated DPC (given by GTT) of the MSU, the DSM card find out a linkset in the routing table to reach that DPC Step6: The linkset table is used to choose a link inside this linkset by using SLS rotation on 4bits in ITU Step7: The slk table is used to find out the SS7 card where the chosen link is plugged

In the SS7 card 1301: The MSU is just routed on the chosen link

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Notes


Configuration of GTT in the Eagle STP

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Notes


GTT and EGTT features

Whereas in ANSI networks the GTT feature of the Eagle STP is sufficient, in ITU it is not as the TT field of CDPA is never used to identify a translation table and additional selectors are required

This is why the EGTT feature must be activated in ITU networks to increase the number of selectors

EGTT provides some additional functions during the processing of gttwhich are compliant with the ETSI recommendations

To activate a feature the following command is used: CHG-FEAT:GTT=ON

To activate EGTT the feature GTT must already be set to ON CHG-FEAT:EGTT=ON

When these features are ON it is not possible to turn them back OFF

Number of Selectors means extract other fields from the CDPA than only the TT field EGTT provide some additional features defined in the ETSI norm:

Deletion of GT Insertion of the SSN into the CDPA Insertion of the OPC into the CGPA EGTT will not check for the presence of gaps in the message length EGTT allows routing of ITU messages without SSN

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Notes


Example of configuration from scratch

Two configurations must be created (one on each STP) to allow SSP 1000 to reach the database 253

SSP SCPSTP

SSN253


2000 30001500

1000

STP

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Notes


Example of configuration: for STP 1500

STP 1500 will perform an Intermediate GTT. The first step is to create the table that will contain the GTAs. The command is:

ENT-GTTSET:GTTSN=TABLE1:NETDOM=ITU:NDGT=7

To specify the domain of the GTAs contained in the table

The name of the table Number of digits in the GTAs contained in this table

All the GTAs from the defined table must have the same number of digits specified by the NDGT parameter

One GTTSET is a bunch of GTA values

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Notes


Example of configuration: STP 1500

When the Eagle STP extracts information from the CDPA, this information is used to find a match with the defined selectors

The second step is to create the selector that will specify which GTTSET table will be used to lookup the GTA and find the translation information The command is:

ENT-GTTSEL:GTIN=4:TT=0:NP=E164:NAI=NATL:GTTSN=TABLE1

Table created on the first step

The N means national but ITU doesnt make any differentiation between national and international

If the CDPA of the MSU contains these values, then table=TABLE1 will be used to translate the GTA

The Eagle STP knows if the MSU comes from a National or International Linkset according the NI field from the MTP3 portion of the MSU

GTII is not used on ITU GTIN is enough as ITU doesnt make any difference between national and international into the SCCP part.

When a selector match, the GTA digits from the CDPA is decoded and his length is compared to the NDGT parameter of the corresponding table

If length of GTA < NDGT => error If length of GTA > NDGT => use leading ndgt on GTA

Note the ES field from the CDPA is never used by an Eagle Command. This value is used internally by the Eagle to extract the GTA digits from the CDPA

The GTTSET command must be entered in the configuration of the Eagle before the GTTSEL command because of the GTTSN parameter

One GTTSET table can have several GTTSEL selectors linked to it

It is not possible to have 2 GTTSEL selectors with the same value for GTI, TT, NP and NAI (to avoid confusion)

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Notes


Example of configuration: STP 1500

The last step is to enter the GTA into the existing table. The command is:

ENT-GTA:GTTSN=TABLE1:GTA=0800345:RI=GT:XLAT=DPC:PCN=2000

GTA we add to this table

The name of the table

To define Intermediate GTT is performed

The result of the translation is a PC

The value of the PC

RI parameter equal SSN in case of a Final GTT

XLAT parameter define what the result of the GTT is. It could be:DPC: means only the PC of the next node is definedDPCSSN: means the PC of the next node is defined and the SSN of the final node which is requested will be fill intothe CDPA. In this case the SSN parameter must be used with the command ent-gtaNGT: means New Global Title. Only the field TT of the CDPA portion can be changed

PCN : means Point Code National. If the result of the translation is an International Point Code, the parameter PCI will beused instead of PCN

The GTA length must be between 1 and 21 (1 and 21 included)

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Notes


Example of configuration: for STP 2000

STP 2000 will perform a Final GTT. The commands to be entered into this STP are:

ENT-GTTSET:GTTSN=TABLE1:NETDOM=ITU:NDGT=7

ENT-GTTSEL:GTIN=4:TT=0:NP=E164:NAI=NATL:GTTSN=TABLE1

For Final GTT before using the ENT-GTA command, another step is required to define the mated applications

ENT-MAP command configure a solitary mode

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Notes


SCCP Network Management Messages

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Notes


SCCP Network Management Messages

When an application on a node becomes unavailable the node sends an SSP to the adjacent points code to inform them the database is no longer reachable

When the application is back up again, the node sends an SSA to the adjacent point codes to inform them the database is now reachable again

SCP253STP2000 3000

SSP

SCP253STP2000 3000

SSA

SSP stands for SubSystem Prohibited

SSA stands for SubSystem Allowed

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Notes


Mated Application for Final GTT

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Notes


Mated Applications: MAP Table

Mated application is used for Final GTT only and is done by accessing the MAP Table in the Eagle STP

In the MAP table an application on a node can be associated with up to 32 other applications on other nodes

As for the MTP3 routing, the parameter RC is used to configure the relation between an application on a node with the other applications on other nodes. 4 possible configurations:

Solitary Mode Dominant Mode Load Sharing Mode Combined Dominant / Load Sharing Mode

RC means Relative Cost

When a PC/SSN pair is not replicated, the pair is in solitary mode. The subsystem acts as the only application, with no backup. If this subsystem fails, messages routed to it are discarded and SCCP management returns Subsystem Unavailablemessages to the originator

A group of replicated PC/SSN pairs are in dominant mode if each PC/SSN pair in the group has a unique relative cost. The specified subsystem acts as the primary point code/subsystem, while the mate point code/subsystem acts as a backup. In the event of congestion, messages route to the mate point code/subsystem. When the congestion subsides, messages are again routed to the primary (dominant) point code/ subsystem

A group of replicated PC/SSN pairs are in load sharing mode if each point code/SSN pair in the group has the same relative cost. All messages are evenly distributed at the SCCP level to both point code/subsystems in the group. In the event of congestion or failure, the non-affected subsystem assumes the load of its failed or congested mate

The combined load sharing/dominant mode supports a combination of load sharing and dominant mode. A group of PC/SSN pairs are in combined load sharing/dominant mode when at least two of the point code/SSN pairs have the same relative cost and another node subsystem in the group has a different relative cost

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Notes


Mated Applications: Example

In many cases applications are deployed in pairs for security and reliability reasons. If a database is not reachable, the request can be processed by using a mated application node

An example of Load Sharing Mode between 2 applications on 2 nodes

SSP SCP253

SCP253

(50) Queries

(25) Queries

(25) Queries

STP

1000

2000 3000

4000

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Notes


Mated Applications: Example

To configure the previous example on the Eagle STP the command is:

ENT-MAP:PCN=3000:SSN=253:RC=50:MPCN=4000:MSSN=253:MATERC=50

The value of the PC

The value of the application

Translated PC after Final GTT and the SSN value contained in the MSU after Final GTT

Relative cost of this couple (PC, application)

Values of the mated couple (PC,application)

Same as for the command for GTT PCN stands for Point Code National. PCI will be used instead if an International Point Code need to be configured

The Mated Applications configuration is not explicitly defined in the command. It is the relative cost values define theconfiguration applied (Dominant, Load Sharing or Combined)

With a command ent-map only 2 mated applications can be entered in the same time. As we can go up to 32 matedapplications we have to enter the command again with the PC and SSN of the result of Final GTT and the new couple (PC, application). For example to add a third PC and Application to this Load Sharing configuration the command would be: ENT-MAP:PCN=3000:SSN=253:RC=50:MPCN=5000:MSSN=253:MATERC=50

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Notes


Mated Applications

Before entering the ENT-GTA command, the DPC of the Final Destination must have been entered into the MAP table with the ENT-MAP command

When a Final GTT is performed on an MSU, before sending this MSU to the translated DPC and the SSN of the Final Destination, a lookup is done in the MAP table to apply for the mated application configuration associated to the translated DPC

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Notes


Example of configuration: STP 2000 (end)

The configuration of STP 2000 can now be completed:

ENT-MAP:PCN=3000:SSN=253:RC=99

ENT-GTA:GTTSN=TABLE1:GTA=0800345:RI=SSN:XLAT=DPC:PCN=3000

After entering both these GTT configurations the database associated with SSN 253 can be requested

But at this stage the response cant be returned to the initiating SSP

ENT-MAP command in this example configure a solitary mode

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Notes


Concerned Signaling Point Code (CSPC)

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Notes


CSPC definition

A CSPC is an STP performing Final GTT that doesnt have adjacent links to the final destination

STPs which have adjacent links to the final destination have to broadcast SCCP Network Management Messages to inform the CSPC STPs about SSP or SSA

SCP253

SCP253

SubsystemProhibited

(SSP)

STP

STP

STP

STP

1000

2000

3000

4000

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Notes


CSPC example in STP 3000

A CSPC Table can be created in the Eagle STP to add these CSPCs. The command is: ENT-CSPC:GRP=GROUP1

Then ENT-CSPC:GRP=GROUP1:PCN=1000 ENT-CSPC:GRP=GROUP1:PCN=2000

In this example the same configuration must be entered into STP 4000

First the list of CSPCs must be created

Each CSPC is inserted to the created list (Group 1 in this example)

A maximum of 32 concerned point codes per group and a maximum of 2549 groups are possible in this table

The point code entered must exist in the Eagle's routing tables and cannot already exist in the specified group

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Notes


CSPC example

The result is:

SCP253

SCP253

SubsystemProhibited

(SSP)

STP

STP

STP

STP

1000

2000

3000

4000CSPC Table GRP=Group1PC=1000PC=2000

CSPC Table GRP=Group1PC=1000PC=2000

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Notes


Variable GTT

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Notes


VGTT Feature

VGTT feature gives some flexibilities for the GTT configuration

All entries in a list of GTAs (GTTSET) must have the same length depending on the value of parameter NDGT when a GTTSET list is created

With VGTT feature the NDGT parameter no longer has to be specified and each list can contain GTAs of different lengths

Up to 10 different GTA lengths are allowed in each GTTSET

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Notes


VGTT Feature

To activate VGTT the feature GTT and EGTT must already be set to ON. Then to activate VGTT the command is:

CHG-FEAT:VGTT=ON

When VGTT is set to ON it cant be set back to OFF

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Notes


VGTT Feature example

Example of different GTA lengths in the same GTTSET

ENT-GTTSET:GTTSN=TABLE1:NETDOM=ITU

ENT-GTTSEL:GTIN=4:TT=0:NP=E164:GTTSN=TABLE1

ENT-GTA:GTTSN=TABLE1:GTA=080040:EGTA=080050:RI=GT:XLAT=DPC:PCN=1500

ENT-GTA:GTTSN=TABLE1:GTA=0800555100:RI=GT:XLAT=DPC:PCN=1500

The NDGT parameter doesnt need to be specified

Example of range of GTAs

GTA of 6 digits and GTA of 10 digits

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Notes


Intermediate GTT Load Sharing

53

Notes


IGTTLS Feature

IGTTLS feature is an additional feature to allow load sharing for STPsperforming Intermediate GTT

It works in the same way as the Mated Application for STPs performing Final GTT

Final GTT uses MAP Table whereas Intermediate GTT uses MRN Table

In the MRN table a node can be associated with up to 32 other nodes

As for the MTP3 routing, the parameter RC is used to configure the relation between a node and other adjacent nodes. There are 3 possible configurations:

Dominant Mode Load Sharing Mode Combined Dominant / Load Sharing Mode

MRN stands for Mated Relay Node

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Notes


IGTTLS Feature

Example of dominant configuration on STP 1000

SCP253

SCP

STP

1000 STP

253STP

STP

STP

STP

2000

3000

40005000

6000

1

2

3

4

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Notes


Example of IGTTLS on STP 1000

The first step is to activate the IGTTLS feature

The IGTTLS feature is not a feature like GTT, EGTT or VGTT. It is a Control Feature, meaning it is protected by a Feature Access Key (FAK)

The command to enable this feature is: ENABLE-CTRL-FEAT:partnum=893006901:fak=CDXHSAN6PHKTE

The command to activate this feature is: CHG-CTRL-FEAT:partnum=893006901:status=ON

Tekelec Identifier of this feature Unique & valid only for this STP

Tekelec Identifier of this feature

Activate the feature

The FAK is computed according the Serial Number of the Eagle STP and is so valid only on that corresponding Eagle STP

IGTTLS can be turned off (mean the MRN Table will no more be lookup) with the following command:CHG-CTRL-FEAT:partnum=893006901:status=ON

56

Notes



Then type the command to enter the configuration into the MRN table: ENT-MRN:PCN=3000:RC=10:PCN1=4000:RC1=20:PCN2=5000:RC2=30

With the RC parameter for each PC defined, the dominant mode hasbeen configured

The GTT will be configured as following: ENT-GTA:GTTSN=TABLE1:GTA=0800345:RI=GT:XLAT=DPC:PCN=3000

After the GTT and before sending the defined the MSU to node 3000, the MRN Table is accessed to find a match with PC 3000

If no match is found, the MSU is sent to PC 3000 If a match is found, the associated configuration is applied. In this example,

if PC 3000 is reachable, the MSU is sent there

In Dominant Mode if the PC designed by the GTT is not available, the next highest value of RC is choosen to send the MSU to the corresponding PC with this RC. If this one is also not available the process continue as the same way

It is possible to define in the GTT that the translated DPC doesnt match with the smallest RC in the MRN table associatedwith this PC. The MSU is anyway sent to this choosen DPC and if it is not available the next highest is choosen (not thesmallest one)

57

Notes



To add the latest STP to this MRN group:

CHG-MRN:PCN=3000:PCN1=6000:RC1=40

Enter one PC of the group

Add the PC with its RC to this group

58

Notes


Limitations of IGTTLS

Eagles will not guarantee correct MSU sequencing when Load Sharing is used. MSUs with the same SLS values may be sent to different nodes

Any given point code can be part of only one point code group, i.e., any point code entered as part of a point code group cannot later be made part of a different point code group, unless it is first deleted from the initial group

An MRN group can contain up to 32 alternate point codes, that can be used for load sharing between multiple nodes

32 alternate point codes since the release 36.0 of the Eagle. Only 8 alternate point codes before this version

59

Notes


Flexible Load Sharing

60

Notes


Flexible Intermediate GTT LS Example

STP

STPSTP

1000

MRNSET1 Table (Dominant Mode)PCN= 2000RC=10PCN= 3000RC=20

MRNSET2 Table (Load Sharing Mode)PCN= 2000RC=20PCN= 3000RC=20

GTA TableGTA=999999 PCN= 2000 MRNSET=MRNSET1GTA=999998 PCN= 2000 MRNSET=MRNSET2

2000

3000

61

Notes


Flexible Final GTT LS Example

STPMAPSET1 Table (Dominant Mode)PCN= 4000 SSN=253RC=10PCN1= 5000 SSN=253RC1=20

MAPSET2 Table (Load Sharing Mode)PCN= 4000 SSN=253RC=20PCN1= 5000 SSN=253RC1=20

GTA TableGTA=999999 PC= 4000 SSN=253 MAPSET=MAPSET1GTA=999998 PC= 4000 SSN=253 MAPSET=MAPSET2

SCP253

SCP253

2000

4000

5000

62

Notes


Origin Based SCCP Routing

63

Notes


Origin Based SCCP Routing Example

STP

2000

4000

5000

SCP253

SCP253

MSC

MSC

1100999999

GTA TableGTA=9194602000 EGTA=9194602200 PC= 4000 SSN=253 XLAT=DPCSSN RI=SSN idx=1

Advanced GTA Tableidx=1 CGPA=999998 PC= 5000 SSN=253 XLAT=DPCSSN RI=SSN

1200999998

For the same mobile when 2 differents MSCs queries an SCP the result of GTT is not the same: For MSC 999999 the GTA table indicate the PC of the SCP 4000. An advanced index exist so the Advanced GTA table must be check. No match is found so the query is sent to the SCP 4000 For MSC 999998 the GTA table indicate the PC of the SCP 4000. An advanced index exist so the Advanced GTA table must be check. A match is found so the query is sent to the SCP 5000

64

Notes


Weighted GTT Load Sharing

65

Notes


Weighted GTT Load Sharing Example

Example of Final GTT

STP

2000

MAPSET1 Table (Combined Dominant / Load Sharing)PC= 4000 SSN=253 RC=10 WEIGHT 70 THR 60PC= 5000 SSN=253 RC=10 WEIGHT 30PC= 6000 SSN=253 RC=20 WEIGHT 60 THR 40PC= 7000 SSN=253 RC=20 WEIGHT 40

GTA TableGTA=999999 PC= 4000 SSN=253 MAPSET=MAPSET1

SCP253

SCP2535000

SCP253

SCP253

4000

6000

7000

Works for Intermediate GTT in the same way. In this case MAPSET is replaced by MRNSET

In normal mode the traffic is load shared between PC 4000 and PC 5000:4000 will carry 70% of the traffic5000 will carry 30% of the traffic

ISWT means In-Service Weight Threshold which means in this example that at least 60% of the traffic must be carry by thisRC. If not the other RC will be use (RC=20 in this example)

If the linkset to 4000 is down, only 30% of the traffic can be carry through 5000, thats not enough because the threshold is 60% so traffic will be load shared between 6000 and 7000

6000 will carry 60% of the traffic 7000 will carry 40% of the traffic

66

Notes


Transaction Based GTT Load Sharing

67

Notes


Modified GTT

68

Notes


Rept-stat-sccp

69

Notes


Lesson Review

Q Which fields are extracted from the MSU by the Eagle STP to perform GTT ?

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TK155 ITU .pdf

Documents

Transcript of TK155 ITU .pdf