Global Title Translation (GTT) is a function usually performed in a Signal Transfer Point (STP). GTT is the procedure by which the destination signaling point and the subsystem number (SSN) is determined from digits (that is, the global title) present in the signaling message.

There are 3 type of numbering plan :

i. E.164  That is MSISDN

ii. E.212 That is IMSI

iii. E.214 That is Mobile Global Title (MGT)

Lets say IMSI is 470070020071316

Here 470 is MCC & 07 is MNC.

Findout the IMSI detail from SGSN:

 

=== root@eqm01s14p2 ANCB ~ # gsh get_imsins 47007

IMSI Number Series             : 47007

Roaming Status                 : Home

Default APN Operator Id        : mnc007.mcc470.gprs

Numbering Plan                 : E.214

Nature of Address              : International

No of Digits to Remove         : 5

Digits to Add                  : 88016

Miscellaneous 1                : 

Miscellaneous 2                : 

Miscellaneous 3                : 

Allow Camel Phase 3            : false

QoS PolicyMap WCDMA            : 2

QoS PolicyMap GSM              : 1

 

According to above IMSI series we need to remove first 5 digits & add 88016 from subscriber IMSI. Let’s Say:

IMSI is 470070020071316

Inorder to find MGT we need to remove first 5 digits from IMSI and add 88016 as prefix. Then it becomes

880160020071316. This is called Mobile Global Title (MGT).

Now we have to find out the SCCP GT tule.

gsh list_ss7_sccp_gtrule

Above command will give the available GT rules in SGSN.

 

A       ss7_sccp_gtrule                 -rn GT_E214_Warid_8801600       -tn GTTrans_E214 

A       ss7_sccp_gtrule                 -rn GT_E214_Warid_8801601       -tn GTTrans_E214 

A       ss7_sccp_gtrule                 -rn GT_E214_Warid_8801602       -tn GTTrans_E214 

A       ss7_sccp_gtrule                 -rn GT_E214_Warid_8801603       -tn GTTrans_E214 

A       ss7_sccp_gtrule                 -rn GT_E214_Warid_88016040      -tn GTTrans_E214 

A       ss7_sccp_gtrule                 -rn GT_E214_Warid_88016041      -tn GTTrans_E214 

Now we have to search the longest match with MGT.

In this case it matchs with 

A       ss7_sccp_gtrule                 -rn GT_E214_Warid_8801600       -tn GTTrans_E214 

To see what the rule is:

gsh get_ss7_sccp_gtrule                 -rn GT_E214_Warid_8801600       -tn GTTrans_E214

Output like:

 

Parameter               Active Data             Planned Data

 

————————————————————

timestamp               20071119030838          _

planState               _                       _

addr                    8801600*                _

ti                      1                       _

en                      ES_HLR01_HLR02_SSN6     _

To see what the Entity is:

gsh get_ss7_sccp_entityset_remote -en ES_HLR01_HLR02_SSN6

Output is like:

 

Parameter               Active Data             Planned Data

 

————————————————————

timestamp               20070414095029          _

planState               _                       _

lsi                     0                       _

pdpc                    3001                    _

popc                    5001                    _

pssn                    6                       _

sdpc                    3002                    _

sopc                    5001                    _

sssn                    6                       _

Here DPC is OPC is 5001 that is SGSN and DPC is 3001 that is HLR, our final destination.

To check all routsets:

gsh list_ss7_mtpl3_routeset

To check all routes in all routesets

gsh list_ss7_mtpl3_altroute

To check a single route:

gsh get_ss7_mtpl3_altroute              -opc 5001       -dpc 3001       -lsid 1

To check avabile linksets:

gsh list_ss7_mtpl3_linkset

To check a single linkset:

gsh get_ss7_mtpl3_linkset               -opc 5001       -lsid 1

To check every link for all linkset:

gsh list_ss7_mtpl3_link_nb

To check hardware equipment & time slot of a link:

gsh get_ss7_mtpl3_link_nb               -opc 5001       -lsid 1         -slc 0

Output:

Parameter               Active Data             Planned Data

————————————————————

timestamp               20061208142732          _

planState               _                       _

eqp                     1.3                     _

trunk                   A                       _

ts                      1                       _

Source : http://mantikore.wordpress.com/