1. EAGLE G-Flex C7 Relay User's Guide
  2. G-Flex C7 Relay (G-Flex) Feature

2 G-Flex C7 Relay (G-Flex) Feature

This chapter describes the G-Flex C7 Relay (G-Flex) feature and the following related functions:
  • DigitAction Expansion
  • G-Flex SCCP Service Re-Route Capability
  • G-Flex in an ANSI environment (ANSI G-Flex)

The chapter includes an overview of the Oracle Communications EAGLE Application Processor (EPAP). EPAP provides the Real Time Database (RTDB) that is used in the database lookup functions.

2.1 Introduction

This chapter describes the G-Flex C7 Relay (G-Flex) feature and the following related functions:
  • The G-Flex Relay function
  • DigitAction Expansion
  • G-Flex SCCP Service Re-Route Capability
  • G-Flex in an ANSI environment

The EPAP Provisioning Blocklist feature is described in EPAP Provisioning Blocklist EPAP Provisioning Blocklist and in EPAP Administration Guide

2.2 G-Flex Feature Description

In today’s mobile networks, subscribers are assigned to Home Location Registers (HLRs) and AuCs (Authentication Centers) in blocks or ranges of subscriber numbers. These ranges are used by MSCs (Mobile Switching Centers) to route many types of signalling messages to HLRs/AuCs. In this document, the term HLR is used to include AuC, as applicable.

G-Flex allows an operator to flexibly assign individual subscribers to HLRs and route signaling messages accordingly, based on subscriber numbering.

The G-Flex C7 Relay node is located in the operator's C7/SS7 network between the MSCs and HLRs. It can also serve as the direct interface to other networks.

There are several types of numbers that identify subscribers, which are assigned by MSCs to HLR/AuCs using this range mechanism:

  • MSISDN (Mobile Station International Integrated Services Digital Network) numbers, which use numbering plan E.164

  • IMSI (International Mobile Subscriber Identity) numbers, which use numbering plan E.212

  • MIN (Mobile Identification Number), which uses the E.164 numbering plan

  • MDN (Mobile Directory Number), which uses the E.164 numbering plan

G-Flex optimizes the use of subscriber numbers and number ranges by providing a logical link between any MSISDN number or IMSI, and an HLR.
  • Subscribers can be easily moved from one HLR to another.
  • Each HLR can be filled to 100% of its capacity by allowing subscriber number ranges to be split over different HLRs and individual subscriber numbers to be assigned to any HLR.
  • Subscriber number routing data is not required to be maintained in all MSCs in the network.

G-Flex is designed to alleviate problems in areas such as network load balancing and efficient use of HLR capacity. Today's rigid scheme for assigning subscribers to HLRs leads to several inefficiencies for network operators, as described in the following examples:

  • When IMSI numbers, which identify the SIM (Subscriber Identity Module), get lost or are otherwise out of service, “holes” sometimes open in the IMSI ranges. These holes result in HLR capacity that cannot be used because switches will not be routing messages using those lost numbers anymore.

  • In many cases, subscribers are “split” across multiple HLRs, as their IMSI range can point to a different HLR than their MSISDN range. Operators must take special steps to ensure that calls are not mishandled.

  • With the advent of MNP (Mobile Number Portability), the MSISDN no longer indicates the subscription network. This leads to holes in the MSISDN ranges that address HLRs. As in the case with IMSIs, these MSISDN holes result in HLR capacity that cannot be used by existing MSC routing schemes.

  • With the advent of MNP, operators need to handle message routing based on MSISDNs that are imported to the network from another operator and do not fit into the existing range mechanism.

  • Prepaid service may result in the allocation of a large block of IMSIs to an HLR, many of which may not be put in service immediately.

  • Corporate clients may reserve a large block of numbers that must be assigned to an HLR. Many of these may not be used immediately, or ever.

2.2.1 Number Conditioning

Incoming SCCP CdPAs (Called Party Numbers) destined for G-Flex processing are conditioned as follows to fit the RTDB lookup requirements where possible:

  • If the G-Flex GTT selectors available in the incoming message match an entry in the Selector table, then the service Numbering Plan from the Selector table entry uses the CdPA Numbering Plan. Further conditioning is applied based on the CdPA Numbering Plan.

  • If the G-Flex GTT selectors available in the incoming message match an entry in the Selector table, then the service Nature of Address from the Selector table entry uses the CdPA Nature of Address. Further conditioning is applied based on the CdPA Nature of Address.

  • If the Nature of Address is National (Significant), the default CC (country code for E.164 or E.214) or default MCC (mobile country code for E.212) is prepended to the number for RTDB look up. The default country code to be used by the EAGLE must be previously provisioned in the GSMOPTS table. If not, a UIM (Unsolicited Information Message) is issued, and the message falls through to GTT.

  • If the Nature of Address is Subscriber, the default CC + default NC (network code for E.164 or E.214) or default MCC + default MNC (for E.212) are prepended to the number. The default codes to be used by the EAGLE must be previously provisioned in the GSMOPTS table. If not, a UIM is issued, and the message falls through to GTT.

  • If the Numbering Plan is E.214, the CC + NC part of the number is replaced with its corresponding MCC + MNC from the provisioned conversion data. If no matching CC + NC has been provisioned, a UIM is issued, and the message falls through to GTT.

Numbers with fewer than 5 digits after the conditioning are not processed by G-Flex. A UIM is issued, and the message falls through to GTT.

Numbers with more than 15 digits after the conditioning are not processed by G-Flex. A UIM is issued, and the message falls through to GTT.

2.2.2 G-Flex Call Flows

Several types of subscriber numbers can be used as a basis for routing messages to HLRs: IMSI, MSISDN, MIN, and MDN.

G-Flex handle the two types of IMSI routing:
  • IMSI routing that uses the actual IMSI (an E.212 number)
  • IMSI routing that uses the Mobile Global Title (MGT), which is an E.214 number derived from the IMSI

G-Flex also handles the MSISDN/MIN/MDN cases, which use the E.164 numbering plan. The call flows in this section address these three cases.

The call flows in this section show only one possible scenario for how messages are routed in the network and where various stages of GTT are performed. G-Flex C7 Relay may perform intermediate or final GTT and/or replace the SCCP (Signaling Connection Control Part) CdPA (Called Party Address) with the HLR entity address, depending on the message received and provisioned data. All call flows here assume that G-Flex C7 Relay is integrated with the EAGLE.

Note:

In GSM networks, each network entity (for example, MSC, HLR, VLR [Visitor Location Register]) is identified by an E.164 entity address. GSM networks also route messages based on E.164 entity addresses when those addresses are known by the sender. While the routing of these messages must also be handled by G-Flex C7 Relay, this function is not considered to be a core part of G-Flex. Because these numbers are not expected to be populated in the G-Flex data, messages routed using these addresses should fall through to normal or enhance) GTT (Global Title Translation). Therefore, call flows for this type of routing are not described here.

MGT (E.214) Routing

The partial Update Location procedure shown in Figure 2-1 is an example of E.214 mobile global title routing. MGT is employed in situations where the E.164 address of the receiving node (labeled HLRB) is not yet known by the sending node (labeled VLRA).

In order to update information about the subscriber's location, VLRA sends a MAP (Mobile Application Part) Update_Location message to the G-Flex Relay (possibly through a Gateway Mobile Switching Center).

The steps in Figure 2-1 are cross-referenced in the following procedure.

  1. The message is received at the G-Flex Relay. Global title information triggers G-Flex processing. Because the SCCP CdPA contains an E.214 number, G-Flex first converts the E.214 number to an international E.212 number before searching the EAGLE Real Time Database (RTDB) with the E.212 number (Step 1). G-Flex also handles the case where an E.212 number is received in the SCCP CdPA. In this case, the database is searched directly using the E.212 number.

  2. G-Flex finds a match with HLR GT information and routes the message to the designated DPC (HLRB) (Step 2).

  3. HLRB responds to VLRA with an Update_Location ack. This message has the E.164 address of VLRA in the SCCP CdPA and is routed by normal or enhanced GTT, not G-Flex (Step 3).

  4. The message is relayed to VLRA (Step 4).

Figure 2-1 E.214 (E.212) Routing Example - Location Updating

img/c_product_description_feature_description_gflex-fig1.jpg

There are other MAP messages from VLR to HLR that also fall into this category of requiring E.214 global title routing. All of these messages are handled the same way by G-Flex, using the process described above.

IMSI (E.212) Routing

G-Flex processing for a message routed with an E.212 number in the SCCP CdPA GTA (Global Title Address) is essentially the same as the processing for a message routed with an E.214 number. The only difference is that the number does not have to be converted to E.212 (since it is already E.212) before doing the database lookup. Therefore, those call flows are not shown here.

MSISDN/MIN/MDN (E.164) Routing

A mobile terminated call results in the GMSC (Gateway Mobile Switching Center) querying the HLR through the use of the called number as a GTA. G-Flex is used to locate the appropriate HLR. The partial mobile terminated call procedure shown in Figure 2-2 is an example of MSISDN global title SCCP addressing. This applies to MIN and MDN routing numbers as well.

The steps in Figure 2-2 are cross-referenced in the following procedure.

  1. A call is originated and an IAM (Initial Address Message) is sent from the originating network to the subscription network (Step 1).

  2. Digit analysis at GMSCB detects a mobile terminated call to a mobile station and generates a MAP Send_Routing_Info (SRI) message to the G-Flex Relay (Step 2).

  3. The EAGLE receives the message. Global title information triggers G-Flex processing. Since the SCCP CdPA contains an E.164 number, G-Flex searches the RTDB with the E.164 number, which must be converted to an international number if it is not one already. The G-Flex finds a match with HLR GT information and routes the message to the designated DPC (HLRB) (Step 3).

  4. HLRB responds to GMSCB with an SRI ack. This message has the E.164 address of GMSCB in the SCCP CdPA, and is routed by normal or enhanced GTT, not G-Flex (Step 4).

  5. The message is relayed to GMSCB (Step 5).

  6. GMSCB sends an IAM containing the MSRN (Mobile Station Roaming Number) to the visited network (Step 6).

Figure 2-2 Mobile Terminated Call

img/c_product_description_feature_description_gflex-fig2.jpg

Other MAP messages that are routed using MSISDN/MIN/MDN global title routing to an HLR are handled the same way by G-Flex. This includes mobile terminated short messages.

2.2.3 G-Flex Relay Function Description

The G-Flex Relay Function (G-Flex Relay) provides the following enhancements to EAGLE GTT:

  • Increased number of translations – The GTT limit is 270,000 total translations. With G-Flex Relay, the number is millions. However, G-Flex Relay translations are only from international MSISDNs and IMSIs to HLRs.

  • Number conditioning – Because the RTDB stores MSISDNs and IMSIs as international numbers and does not store MGTs, G-Flex provides the capability to condition incoming numbers to be international MSISDNs or IMSIs for the database look up.

  • Provides discrimination of messages that need its functionality – Because G-Flex is used only for translating to HLRs, it provides a method to identify which messages are processed by G-Flex Relay and which by. GTT. This is provided using a G-Flex Service Selector table that defaults back to the GTT Selector table if a match is not found, and by providing SSN-based discrimination.

  • Variable number of digits – There is no fixed number of digits for MSISDNs or IMSIs. For example, a 12-digit MSISDN can coexist with a 15-digit one. However, the number of digits of the stored numbers must be between 5 and 15.

  • Replacement of GT with entity address – The ability to set the outgoing CdPA GT (NP, NAI, ES, GTAI) to the HLR international entity number is provided.

Figure 2-3 shows the basic functioning of SCCP, with the parts for G-Flex in bold.

Figure 2-3 G-Flex in SCCP

img/c_gflex_relay_function_feature_description_gflex-fig1.jpg

In order to keep the diagram simple, the only error conditions shown are the no-match cases for G-Flex and GTT selectors and translations. G-Flex has its own error handling for some cases that issues UIMs and peg measurements appropriately before letting the MSU fall through to GTT translation. Also, there are error conditions in GTT selection, GTT translation, and message transfer that are handled by GTT error handling.

G-Flex Relay is performed in the following stages.

  1. The message arrives at EAGLE Route-on-GT. The EAGLE decodes the SCCP portion and uses the data to perform G-Flex selection based on the CdPA GT fields other than the ES and GTAI. The result of this selection provides two pieces of data, identification of the NP and NAI for G-Flex and a G-Flex Service Indicator. The Service Indicator is G-Flex if G-Flex Relay is required. If a G-Flex selector does not match the incoming GT fields, then GTT selection is attempted. It is possible that G-Flex and GTT selectors will not match the incoming GT fields. In this case, GTT error handling is used.

  2. If stage 1 indicates that G-Flex Relay is required and if the message is not a UDTS-generated by the EAGLE, the EAGLE performs SSN-based discrimination. If the G-Flex service state is ONLINE, then step 3 is performed. Otherwise, G-Flex SCCP Service Re-Route is performed.

  3. The conditioned number is looked up in the RTDB.

  4. If the number is found, the translation data for the number is used to alter and route the message.

  5. If G-Flex Relay is not required, or the number is not found in the RTDB, the set of GTT translations is used for translation.

Table 2-1 lists possible combinations for G-Flex selector and G-Flex data provisioning, and the resulting action of G-Flex Relay.

Table 2-1 G-Flex Relay Data Combinations

G-Flex Selector Matches Incoming GT Number in RTDB EAGLE Action

No

N/A

GTT used

Yes

No

Fall-through to GTT

Yes

Yes

G-Flex translation

G-Flex Relay is divided into the following subtasks:

  • Conversion of national/local numbers to international numbers

  • Conversion of E.214 MGT to E.212 international IMSI

  • RTDB lookup

  • Message forwarding

  • Error handling

2.2.3.1 Conversion of National/Local Numbers to International Numbers
G-Flex stores international DNs and IMSIs in the RTDB. SCCP CdPA numbers may need to be converted to international numbers in order to do an RTDB lookup. When a message needs G-Flex Relay and has either a national (significant) number or Subscriber Number as the Service NAI, then the national/local to international number conversion is triggered. G-Flex uses the SCCP CdPA GTAI number and its SNAI to convert to an international number based on the numbering plan. See Table 2-2.

Table 2-2 National/Local Numbers to International Numbers Conversion Logic

Service Numbering Plan Service Nature of Address Action

E.164

National (Significant) number

Prepend GTAI digits with the default E.164 Country Code (CC).

E.164

Subscriber number

Prepend GTAI digits with the default E.164 country code (CC) and network code (NC).

E.212

National (Significant) number

Prepend GTAI digits with the default mobile country code (MCC).

E.212

Subscriber number

Prepend GTAI digits with the default Mobile Country Code (MCC) and Mobile Network Code (MNC).

E.214

National (Significant) number

Prepend GTAI digits with the default E.164 Country Code (CC).

E.214

Subscriber number

Prepend GTAI digits with the default E.164 Country Code (CC) and Network Code (NC).

Other

N/A

Assume the default to be E.164 International number

Notes:

  • If any of the default CC, NC, MCC, or MNC are required for conversion and are not provisioned in the database, G-Flex Relay issues a UIM and falls through to GTT.

  • If the converted number is fewer than five digits, G-Flex Relay falls through and performs GTT on the message. G-Flex Relay issues a UIM when a converted number is fewer than five digits.

  • If the converted number is more than 15 digits, then G-Flex Relay issues a UIM when the number exceeds 15 digits and falls through to GTT.

  • G-Flex Relay uses the conditioned number for database lookup purposes only and does not modify the CdPA GTAI in the message unless rcgta=yes or ccgt=yes.

  • For the G-Flex selector-specified service numbering plan (IMSI, DN, or MGT), the numbering plan in the incoming message is replaced with the G-Flex Selector service numbering plan (E.164, E.212, or E.214, respectively). This is for RTDB lookup purposes only.

2.2.3.2 Conversion of E.214 MGT to E.212 IMSI

Because the RTDB does not store MGTs, the messages with E.214 MGT in the CdPA GTAI are converted to an E.212 International IMSI in order to perform the RTDB lookup. G-Flex maintains a logical MGT2IMSI conversion table to perform this conversion. The MGT2IMSI conversion table contains up to ten entries of E.164 part (CC + NC digits) and its corresponding E.212 part (MCC + MNC). If a G-Flex message has E.214 as the CdPA numbering plan, G-Flex Relay performs the following steps to derive the E.212 International IMSI:

  1. G-Flex Relay uses MGT as the key and does a lookup in the MGT2IMSI conversion table to find a match on E.164 part (CC + NC digits).

  2. If a match is found, G-Flex Relay replaces the matched digits of the MGT with the corresponding E.212 part (MCC + MNC digits). If a match is not found, a UIM is issued and the G-Flex Relay falls through to GTT.

  3. G-Flex Relay uses this complete E.212 International IMSI number to do the RTDB lookup.

Note:

If the IMSI for a particular country/network is the complete 15 digits and the E.164 CC + NC for that country is more than five digits, the MGT generated could contain a truncated MSIN. This is possible because the converted MGT is more than 15 digits and the maximum number of digits allowed in the MGT is 15 digits. (Refer to E.214 for more details on conversion.) Under these circumstances, the MGT is truncated at 15 digits. Therefore, the MGT-to-IMSI reconversion would not regenerate a complete IMSI and would lead to incorrect results and errors.
2.2.3.3 RTDB Lookup

G-Flex Relay performs the RTDB lookup using either the complete international DN or IMSI. If the DN or IMSI number is found in the RTDB and it has an HLR translation, then G-Flex Relay extracts the HLR translation data and generates a forwarding message. G-Flex Relay falls through and performs GTT for the following error cases:

  • The DN number is not present in the database.

  • The IMSI number is not present in the database.

The preceding error cases do not generate any UIM or UAM, but fall through to GTT processing.

If the RTDB lookup is for GTI=2 and is an even number of digits ending in 0, then G-Flex performs a less than or equal to lookup for the odd number of digits (digit length minus 1). If a match is found, G-Flex saves the record and record index.

G-Flex then tries to continue to find an exact match on the even number of digits. If the exact match is found in the RTDB, then the HLR translation data corresponding to the even number of digits record is used. Otherwise the HLR translation data corresponding to the found odd number of digits record is used. If the even and odd translation is not found, then the G-Flex Relay falls through and performs GTT.

The important issue is that the less than or equal to search re-enters the search where the comparison left off. This minimizes any impact on performance for this special case.

2.2.3.4 Message Forwarding

GFRF Forwarding Message: MTP Portion

G-Flex modifies the MTP routing label to include the HLR PC as the DPC and the EAGLE true PC as the OPC. G-Flex modifies the MTP Level 2 length based on the size of the forwarding message. Table 2-3 lists the fields modified by G-Flex Relay.

Table 2-3 G-Flex Relay Forwarding Message: MTP Portion

Fields Values

MTP Level 2 length

Number of octets in response MSU starting from MTP3 SIO field. If number of octets is greater than 63, Level 2 length is set to 63

MTP Level 3 DPC

Point code obtained from the HLR GT information in RTDB

MTP Level 3 OPC

EAGLE true PC

G-Flex Relay Forwarding Message: SCCP Portion

The following functions are performed for the SCCP portion of the message:

Replacing the CdPA GTAI digits with the HLR entity number

When an MSISDN or IMSI number is found in the RTDB and the Replace GT flag is set for this entry, G-Flex Relay replaces the CdPA GTAI digits with the provisioned HLR entity number. G-Flex also modifies the numbering plan (E.164), nature of address (international), and encoding scheme to match the HLR entity number.

G-Flex Relay does not replace the Global Title Indicator format (GTI) element of the GT.

Replacing of SSN in the CdPA

When the HLR translation data includes a SSN, G-Flex Relay replaces the SSN in the called party address of the message with the new SSN. If the SSN is not present in the incoming message, then G-Flex Relay updates the Subsystem Number Indicator and includes the new SSN in the Called Party Address of the message before it forwards the message to the next node.

Inclusion of OPC in the CgPA

When the routing indicator of the calling party address is set to Route-on-SSN, and no SPC is present in it, the OPC from the received message is taken and inserted into the CgPA before the message is forwarded to the next node.

Deleting the CdPA GT Digits

When G-Flex performs Final-GTT, the Routing Indicator of the Called Party Address is set to Route-on-SSN. G-Flex provides an option to delete the Global Title present in the Called Party Address. If the Delete GT option is set, G-Flex modifies the GTI to zero and deletes the GT information from the SCCP CdPA before the message is forwarded to the end node. Table 2-4 summarizes the possible changes by G-Flex Relay to the SCCP fields.

Table 2-4 G-Flex Relay Forwarding Message: SCCP Portion

Field Value

SCCP CdPA Length

New CdPA length after the possible modifications

SCCP CdPA Routing indicator

Routing Indicator obtained from the RTDB. (GT or DPCSSN)

SCCP CdPA Global Title Indicator

Same as incoming message or zero

SCCP CdPA Subsystem Number Indicator

Same as incoming message or replaced/inserted with the subsystem number indicator based on the existence of the SSN provisioned in the HLR translation

SCCP CdPA SSN

Same as incoming message or replaced/inserted with the SSN provisioned in the HLR translation

SCCP CdPA GT

Same as incoming message or replaced or deleted with HLR entity address provisioned in the RTDB

SCCP CgPA Length

New CgPA length after the possible modifications

SCCP CgPA Point Code Indicator

Same as incoming message or if CgPA RI is Route-on-SSN and PCI is not 1, then set PCI to 1

SCCP CgPA SPC

If the CgPA RI is Route-on-SSN and no point code is present in the CgPA SPC, then the OPC is included as the SPC (Secondary Point Code)

SCCP CdPA Subsystem Number Indicator

Same as incoming message or replaced/inserted with the Subsystem Number indicator based on the existence of the SSN provisioned in the HLR translation

Error Handling

The purpose of the Error Handling is to discard or return messages that encounter routing and database failures and cannot be delivered to the HLR. When G-Flex Relay is unable to transfer a message and Return on Error is set, then G-Flex Relay follows the same error handling procedures used by GTT. The DATA field of the UDT message and the reason cause for return are included in UDTS message.

G-Flex Relay follows the same error handling procedures as GTT for the following error cases:

  • Routing failures

  • Network congestion

Forwarding message after replace GT and/or Insertion of OPC or SSN is greater than the CCS7 message limit (272 bytes).

An exception to GTT error handling is when the G-Flex Relay RTDB entry cannot be found. In this case, it is not considered an error and the G-Flex Relay capability will forward the message to GTT processing.

2.2.4 MTP-Routed SCCP Message Processing

An MTP-routed message is a “through-switched” message that is not generated by or destined to the EAGLE (neither the MTP OPC nor DPC is the EAGLE true point code or capability point code). An MTP-routed message is routed to the destination designated by the DPC of the MTP3 routing label.

Typically, MSUs that receive service on a Service Module card require the message to be GT-routed to the EAGLE, so that GTT service selector-based discrimination can be applied to the message to select a specific service (such as GFLEX).

When the MTP Routed Messages for SCCP Applications (MTP Msgs for SCCP Apps) feature is on, it forwards all incoming MTP-routed SCCP messages (SI=3 in the message) from LIM cards to Service Module cards for processing. The feature is available system-wide and can be enabled and turned on when the GTT feature is turned on.

If the MTP-routed message arrives with the CdPA RI=GT or RI=SSN, and the CdPA GTI=2 (ANSI) or GTI=2 or 4 (ITU), service selection is performed.
  • If the GFLEX service is selected, then the message is handled by the GFLEX service and the message processing is the same as that used for GT-routed messages.
  • If the service selection does not find a match, or if the service is OFFLINE, then the message is MTP-routed.

Service re-route is not performed on MTP-routed messages.

The GFLEX service is not supported for MTP-routed messages that contain SCCP CdPA GTI=0.

2.2.5 G-Flex Configuration Options

The GSMOPTS table contains configuration option values for the G-Flex feature and the G-Flex MAP Layer Routing (G-Flex MLR) feature. The GSMOPTS option data is loaded to the LIM cards and to Service Module cards that contain the RTDB database. The configuration option values influence number conditioning, response message formatting and generation, and G-Flex MLR processing.

The GSMOPTS options described in Table 2-5 can be provisioned only after the G-Flex feature and the G-Flex MLR feature are enabled and turned on.

Table 2-5 GSMOPTS Configuration Options for G-Flex and G-Flex MLR

Parameter Value Description Notes

CCNC - Country Code and Network Code

2-8 digits   Mandatory when the MCCMNC parameter is specified.

DEFMCC - E.212 Default Mobile Country Code

 3 hexadecimal digits, NONE   The value NONE deletes the current parameter value.

DEFMNC - E.212 Default Mobile Network Code

 1-4 hexadecimal digits, NONE   The value NONE deletes the current parameter value.
MCCMNC - E.212 Mobile Country Code and Mobile Network Code 4-7 hexadecimal digits, NONE Specifies the CgPN NAI that is used during number conditioning. The value NONE deletes the current parameter value.
GFLEXMAPLAYERRTG - G-Flex MAP Layer Routing status ON G-Flex MLR is performed. The G-Flex MLR feature must be on to specify this parameter.
  OFF G-Flex MLR is not performed.  
GFLEXMAPLAYERRTG - Type of G-Flex MLR to be performed (see G-Flex MAP Layer Routing) NONE G-Flex MLR is not performed. The G-Flex MLR feature must be on to specify this parameter.
IMSI Use the IMSI parameter value for RTDB lookup.
MSISDN Use the MSISDN parameter value for RTDB lookup.
ALL Use the IMSI or the MSISDN parameter value for RTDB lookup, based on the message operation code.
MAPLYRRTGON

MAPLYRRTGOFF - Perform (ON) or do not perform (OFF) G-Flex MLR for each specified operation or all operations (see G-Flex MAP Layer Routing)

REGSS Perform (ON) or do not perform (OFF) G-Flex MLR processing for the registerSS operation. The G-Flex MLR feature must be on to specify these parameters.
ACTSS Perform (ON) or do not perform (OFF) G-Flex MLR processing for the activateSS operation.
DACTSS Perform (ON) or do not perform (OFF) G-Flex MLR processing for the deactivateSS operation.
INTROSS Perform (ON) or do not perform (OFF) G-Flex MLR processing for the interrogateSS operation.
AUTHFAILRPT Perform (ON) or do not perform (OFF) G-Flex MLR processing for the authenticationFailureReport operation.
RSTDATA Perform (ON) or do not perform (OFF) G-Flex MLR processing for the restoreData operation.
PROCUNSTRQT Perform (ON) or do not perform (OFF) G-Flex MLR processing for the processUnstructuredSS-Request operation.
RDYFORSM Perform (ON) or do not perform (OFF) G-Flex MLR processing for the readyForSM operation.
PURGMOBSS Perform (ON) or do not perform (OFF) G-Flex MLR processing for the purgeSS operation.  
SRILOC Perform (ON) or do not perform (OFF) G-Flex MLR processing for the sendRoutingInfoForLCS operation.  
ALL Perform (ON) or do not perform (OFF) G-Flex MLR processing for all 10 of the listed operations.  

2.2.6 DigitAction Expansion

DigitAction Expansion provides more flexibility to formulate the SCCP (SCCP) Called Party Address (CdPA) Global Title Address (GTA) field of the MAP messages relayed by G-Flex.

Without DigitAction Expansion, G-Flex supports four options (none, insert, prefix, and replace) to overwrite the SCCP CdPA GTA field. With DigitAction Expansion, four additional options (delcc, delccprefix, spare1, and spare2) are included to overwrite the SCCP CdPA GTA field.

DigitAction Expansion is provisioned using the PDBI Enter Network Entity or Update Network Entity commands. DigitAction Expansion can also be modified using the Add an NE and Update an NE EPAP GUI screens.

The rules for formatting the SCCP CdPA GTA field are based on the value specified in the DigitAction field. If DigitAction = none, the EAGLE does not overwrite the SCCP CdPA GTA. For all other values, the EAGLE formats the SCCP CdPA GTA according to the value assigned to DigitAction. See Table 2-6 for examples of DigitAction Expansion on the SCCP CdPA GTA of an outgoing message when the Entity ID = 1404 and the default country code = 886.

Table 2-6 DigitAction Applications

DigitAction Value in Incoming CdPA GTA Value in Outgoing CdPA GTA Meaning

none

886944000213

886944000213

No change to the Called Party GTA (default)

prefix

886944000213

1404886944000213

Prefix Called Party GTA with the entity id

replace

886944000213

1404

Replace Called Party GTA with the entity ID

insert

886944000213

8861404944000213

Insert entity ID after country code. (CC + Entity Id + NDC + SN)

delccprefix

886944000213

1404944000213

Delete country code and add prefix

(No action is taken if country code is not present.)

delcc

886944000213

944000213

Delete country code

spare1

886944000213

treated as none

No change to the Called Party GTA (default)

spare2

886944000213

treated as none

No change to the Called Party GTA (default)

Digit Action DELCCPREFIX

The Digit Action to delete country code if present and prefix database entity feature allows the DELCCPREFIX Digit Action to be applied to the Called Party Global Title Address (CdPA GTA) when the GTA has a National format, as well as when the GTA has an International format. The DELCCPREFIX option in the SCCPOPTS table specifies how the DELCCPREFIX digit action is applied to a Called Party Global Title Address (CdPA GTA).

  • When the SCCPOPTS:DELCCPREFIX option is set to PFXWCC, the DELCCPREFIX digit action is applied to the CdPA GTA only when the address has a International format. The Country Code is deleted and the GTA is prefixed with the Entity ID.
  • When the SCCPOPTS:DELCCPREFIX option is set to PFX4ALL, the DELCCPREFIX digit action is applied to the CdPA GTA in all cases. For an International format, the Country Code is deleted and the GTA is prefixed with the Entity ID. For a National format, the GTA is prefixed with the Entity ID.

The chg-sccpopts command is used to specify the delccprefix parameter value to configure the DELCCPREFIX Digit Action functionality.

2.2.7 G-Flex SCCP Service Re-Route Capability

G-Flex SCCP Service Re-Route Capability provides the ability to re-route the traffic from one EAGLE to other G-Flex nodes within an operator's network, and inform the originating nodes to re-route the G-Flex service related traffic to other G-Flex service nodes. The following functions are used to provide G-Flex re-routing capability:
  • Service Capability Point Codes
  • Service State
  • Service Re-routing (using alternate point codes and a configuration option)

Service State

G-Flex SCCP Service Re-Route Capability provides an option to change the state of the G-Flex service to OFFLINE or ONLINE. The service state is persistent. Booting the OAM or all of he Service Module cards would not change the service state. The service state must be manually changed .
  • The G-Flex service state defaults to OFFLINE when the G-Flex feature is turned on in the system. The service must be set to ONLINE and at least one Service Module card must be IS-NR (In-Service-Normal) before G-Flex processing occurs in the system.
  • The G-Flex service can be taken OFFLINE at any time, such as when the databases are incoherent or Service Module cards need to be reloaded for some reason. Taking the service OFFLINE causes processing of G-Flex traffic to stop and allows a controlled re-routing procedure to be performed. A Critical UAM is generated as a warning that the G-Flex service is disabled because it has been taken OFFLINE.

Service Re-routing

Service re-routing is optional and does not affect normal G-Flex processing.

Service re-routing can be enabled by using the chg-sccp-serv command to define a list of alternate PCs or to set the GTT option to YES. Re-routing is initiated by taking a service OFFLINE.
  • If alternate PCs are provisioned any messages destined to that service would be re-routed to available alternate PCs defined for that service. Up to 7 alternate point codes per domain can be defined. ANSI, ITU-I, ITU-N, ITU-I spare, ITU-N spare, and ITU-N24 domains are supported. An entire set of alternate point codes is called a Re-route set. Intermediate GTT loadsharing rules apply to the Alternate PC Re-route set.
  • The GTT option is used if alternate PCs are not provisioned or none of them are available. If the GTT option value is YES (the default), then messages destined to that service would fall through to GTT as part of the re-routing procedure.

Service Capability Point Codes

One or more G-Flex Capability Point Codes (CPC) can be provisioned when the G-Flex feature is on. The Capability Point Code is used to distinguish G-Flex messages from other types of messages, so that the G-Flex service OFFLINE state can be reported by sending response method TFPs to G-Flex nodes. (Response method TFx messages are not generated if CPCs are not used.)

The service CPCs aid the adjacent nodes in knowing about a service outage. When a service is taken OFFLINE and capability point codes are defined for the service, the following actions occur for all traffic destined to the service node:
  • A response method TFP message is generated to the adjacent node about the service CPC.
  • The TFP response to the adjacent node causes the traffic-originating nodes to stop sending service traffic to this node.
  • All service traffic coming into this node is sent to the alternate service nodes.
  • Adjacent nodes initiate route-set-test procedures after receipt of the TFP.

If the messages are destined to the EAGLE true point code, then TFP messages are not generated when a service is OFFLINE, and the originator would not be aware of the outage.

After the service is back ONLINE in the EAGLE, a TFA message is sent to the traffic-adjacent nodes in response to route-set-test message. The traffic-originating nodes then start sending service traffic to this node.

2.2.7.1 G-Flex Re-Route Message Handling

Table 2-7 shows the actions that the EAGLE takes with the G-Flex service is OFFLINE, a message requiring G-Flex service arrives at the affected node, and Service Module cards are available.

Table 2-7 G-Flex SCCP Re-Route Message Handling Summary

DPC Alternate PC Defined and Available GTT to be Performed as Fall Through Message Handling Network Management
G-Flex CPC Yes N/A Rer-oute to alternate PC based on Relative Cost (RC) TFP concerning CPC
G-Flex CPC No (Defined, and prohibited or congested) Yes Fall through to and perform GTT TFP concerning CPC
G-Flex CPC No (Defined, and prohibited or congested) No Generate UDTS (Return Cause = Network Failure) TFP concerning CPC
G-Flex CPC Not Defined Yes Fall through to and perform GTT TFP concerning CPC
G-Flex CPC Not Defined No Generate UDTS (Return Cause = No xlation for this addr) TFP concerning CPC
True or Secondary PC or non-G-Flex CPC Yes N/A Re-route to alternate PC based on Relative Cost (RC) None
True or Secondary PC or non-G-Flex CPC No (Defined, and prohibited or congested) No Generate UDTS (Return Cause = Network Failure) None
True or Secondary PC or non-G-Flex CPC No (Defined, and prohibited or congested) Yes Fall through to and perform GTT None
True or Secondary PC or non-G-Flex CPC Not Defined Yes Fall through to and perform GTT None
True or Secondary PC or non-G-Flex CPC Not Defined No Generate UDTS (Return Cause = No xlation for this addr) None

Table 2-8 shows the actions of LIM re-route functions when Service Module cards are unavailable or down.

Note:

G-Flex does not support Rt-on SSN.

* If some Service Module cards are available but are overloaded, this is considered a partial failure.

Table 2-8 G-Flex LIM Card Re-Route Message Handling Summary

Routing Indicator in Incoming Message DPC Full or Partial Failure G-Flex Service Status Message Handling Network Management
Rt-on-GT G-Flex CPC Full N/A Generate UDTS TFP concerning CPC, UPU
Rt-on-GT Non-G-Flex CPC Full N/A Generate UDTS TFP concerning CPC, UPU
Rt-on-GT True PC Full N/A Generate UDTS UPU
Rt-on-GT G-Flex CPC Partial* ONLINE Generate UDTS None
Rt-on-GT True PC or non-G-Flex CPC Partial* ONLINE Generate UDTS None
Rt-on-GT G-Flex CPC Partial* OFFLINE Generate UDTS TFP concerning CPC, UPU (ITU only)
Rt-on-GT True PC or non-G-Flex CPC Partial* OFFLINE Generate UDTS None
Rt-on-SSN G-Flex CPC N/A N/A Generate UDTS None

Route-Set-Test Messages

When the G-Flex service is OFFLINE,
  • If a Route-Set-Test Message - Prohibited (RSP) is received for a G-Flex CPC, the EAGLE does not reply.
  • If a Route-Set-Test Message - Restricted (RSR) is received for a G-Flex CPC, the EAGLE replies with a TFP concerning the CPC.

When the G-Flex service is ONLINE and at least one Service Module card is in the IS-NR state, the EAGLE replies with a TFA message to RSRs and RSPs for the G-Flex CPC.

Gateway Screening and GSM MAP Screening

Gateway Screening and GSM MAP Screening are not performed on messages that are re-routed to alternate PCs.

If G-Flex Re-Route processing falls through to GTT based on the SCCP-SERV GTT configuration option, Gateway Screening and GSM MAP Screening can be applied after GTT translation.

2.2.8 G-Flex in an ANSI Environment

The Support ANSI G-Flex at 1700 TPS per DSM function increases the transaction capacity of the G-Flex feature running on a Service Module card from 850 TPS to 1700 TPS for ANSI systems. (ITU systems operate at 850 TPS per DSM.)

The STPOPTS ANSIGFLEX option (chg-stpopts:ansigflex=yes command) allows Service Module cards to operate at 1700 TPS when the G-Flex feature is ON. The default for the ANSIGFLEX system option is NO (disabled).

The G-Flex feature must be on, no other EPAP-related features can be on, and no ITU service selectors can be provisioned, before the ANSIGFLEX system option can be set to YES.

The ANSIGFLEX system option can be set to NO after it has been set to YES. Service Module card TPS granting is reduced to 850 TPS when the option setting is NO. A notification to the user concerning the reduction in SCCP capacity is generated.

Although a warning message is provided when the ANSIGFLEX option is set to NO, the user must perform system checks manually to ensure that SCCP system capacity will be sufficient after the ANSIGFLEX option is set to NO. If the user does not perform these capacity checks, the system may discard SCCP messages (TVG grant failures).

The SCCP capacity is reported in the rept-stat-sccp:mode=perf command output; the command lists the performance of all Service Module cards, including message rates for TVG. The TVG capacities that are reported in the rept-stat-sccp command take into account the ANSIGFLEX system option.

2.2.9 G-Flex as a "Stand-Alone" Node

G-Flex can be deployed two ways (the G-Flex processing is the same for both ways, as described in this manual):

  • As an integrated part of the STP (Signal Transfer Point)

  • As a "stand-alone" node

    Destinations, routes, and point codes can be configured so that one STP of a mated EAGLE pair performs only G-Flex processing, while the other STP performs all of the STP other functions.

2.2.10 Assumptions/Limitations

The following assumptions and limitations apply.

  1. The EAGLE does not perform any conversion in the SCCP portion of the message to support message routing across the domain boundary (ANSI to ITU and visa versa).

  2. The EAGLE supports message routing across network boundaries (ITU-N to ITU-I and visa versa). However, GTT and Enhanced GTT (EGTT) do not modify the National Indicator bit in the CdPA Address Indicator (AI) or convert the CdPA PC (Point Code) to match the network type.

  3. For messages with E.214 numbers in the SCCP CdPA, a simple conversion can form an E.212 number. The E.212 number formed in this way is the full IMSI of the subscriber, that is, it is assumed that no truncation occurs when the E.214 number is originally formed from the E.212 number. Such truncation is allowed by the E.214 recommendation.

  4. G-Flex allows for up to eight MSISDN numbers per subscriber (that is, per IMSI) to be related. It is assumed that operators do not need to support more than eight MSISDN numbers per subscriber.

  5. No overload controls are required beyond the existing EAGLE lower level mechanisms (for example, for MTP congestion)

  6. Using combinations of the GTT selectors GTI (Global Title Indicator), TT (Translation Type), NP (Number Portability), and NAI as triggers for G-Flex processing plus SSN discrimination provide the ability to limit G-Flex processing to only the messages for which it is appropriate.

  7. G-Flex C7 Relay supports message routing to a single network node for a particular subscriber. For example, an individual subscriber cannot have some messages routed to his HLR and other messages routed to a separate AuC. In this example, G-Flex does not support the AuC being collocated with the HLR.

  8. For performance estimates, EAGLE-generated UDTS messages will count as two processed messages.

2.3 Hardware Requirements

EPAP-related features that perform an RTDB lookup require Service Module cards (E5-SM4G, E5-SM8G-B, or SLIC cards) running the SCCPHC application. The EAGLE can be equipped with up to 32 (31+1) Service Module cards.

Features that do not perform an RTDB lookup require Service Module cards only for GTT processing that might be performed for the feature. These features can coexist in systems with EPAP, but do not require an EPAP connection.

2.4 MPS/EPAP Platform

Oracle provides the Multi-Purpose Server (MPS) platform as a subsystem of the Oracle Communications EAGLE. The MPS provides support for EPAP-related features that perform Real Time Database (RTDB) lookups.

The MPS is composed of hardware and software components that interact to create a secure and reliable platform. For details about the MPS hardware, refer to Application B Card Hardware and Installation Guide. The MPS provides the means of connecting the customer provisioning application with the EAGLE and accepts the customer number portability data, while accommodating numbers of varying lengths.

The Oracle Communications EAGLE Application Processor (EPAP) is software that runs on the MPS hardware platform. EPAP collects and organizes customer provisioning data, and forwards the data to the EAGLE Service Module cards. For detailed information about EPAP, refer to Administration Guide for EPAP.

In this manual, Service Module card refers to an E5-SM4G, E5-SM8G-B, or SLIC card unless a specific card is required. For more information about the supported cards, refer to Hardware Reference.