Operator Policy

The proprietary concept of an operator policy, originally architected for the exclusive use of an SGSN, is non-standard and currently unique to the ASR 5500. This optional feature empowers the carrier with flexible control to manage functions that are not typically used in all applications and to determine the granularity of the implementation of any operator policy: to groups of incoming calls or to simply one single incoming call.

The following products support the use of the operator policy feature:

  • MME (Mobility Management Entity - LTE)
  • SGSN (Serving GPRS Support Node - 2G/3G/LTE)
  • S-GW (Serving Gateway - LTE)

This document includes the following information:

What Operator Policy Can Do

Operator policy enables the operator to specify a policy with rules governing the services, facilities and privileges available to subscribers.

A Look at Operator Policy on an SGSN

The following is only a sampling of what working operator policies can control on an SGSN:
  • APN information included in call activation messages are sometimes damaged, misspelled, missing. In such cases, the calls are rejected. The operator can ensure calls aren't rejected and configure a range of methods for handling APNs, including converting incoming APNs to preferred APNs and this control can be used in a focused fashion or defined to cover ranges of subscribers.
  • In another example, it is not unusual for a blanket configuration to be implemented for all subscriber profiles stored in the HLR. This results in a waste of resources, such as the allocation of the default highest QoS setting for all subscribers. An operator policy provides the opportunity to address such issues by allowing fine-tuning of certain aspects of profiles fetched from HLRs and, if desired, overwrite QoS settings received from HLR.

A Look at Operator Policy on an S-GW

The S-GW operator policy provides mechanisms to fine tune the behavior for subsets of subscribers. It also can be used to control the behavior of visiting subscribers in roaming scenarios by enforcing roaming agreements and providing a measure of local protection against foreign subscribers.

The S-GW uses operator policy in the SGW service configuration to control the accounting mode. The default accounting mode is GTPP, but RADIUS/Diameter and none are options. The accounting mode value from the call control profile overrides the value configured in SGW service. If the accounting context is not configured in the call control profile, it is taken from SGW service. If the SGW service does not have the relevant configuration, the current context or default GTPP group is assumed.

The Operator Policy Feature in Detail

This flexible feature provides the operator with a range of control to manage the services, facilities and privileges available to subscribers.

Operator policy definitions can depend on factors such as (but not limited to):
  • roaming agreements between operators,
  • subscription restrictions for visiting or roaming subscribers,
  • provisioning of defaults to override standard behavior.

These policies can override standard behaviors and provide mechanisms for an operator to circumvent the limitations of other infrastructure elements such as DNS servers and HLRs in 2G/3G networks.

By configuring the various components of an operator policy, the operator fine-tunes any desired restrictions or limitations needed to control call handling and this can be done for a group of callers within a defined IMSI range or per subscriber.

Re-Usable Components - Besides enhancing operator control via configuration, the operator policy feature minimizes configuration by drastically reducing the number of configuration lines needed. Operator policy maximizes configurations by breaking them into the following reusable components that can be shared across IMSI ranges or subscribers:
  • call control profiles
  • IMEI profiles (SGSN only)
  • APN profiles
  • APN remap tables
  • operator policies
  • IMSI ranges

Each of these components is configured via a separate configuration mode accessed through the Global Configuration mode.

Call Control Profile

A call control profile can be used by the operator to fine-tune desired functions, restrictions, requirements, and/or limitations needed for call management on a per-subscriber basis or for groups of callers across IMSI ranges. For example:
  • setting access restriction cause codes for rejection messages
  • enabling/disabling authentication for various functions such as attach and service requests
  • enabling/disabling ciphering, encryption, and/or integrity algorithms
  • enabling/disabling of packet temporary mobile subscriber identity (P-TMSI) signature allocation (SGSN only)
  • enabling/disabling of zone code checking
  • allocation/retention priority override behavior (SGSN only)
  • enabling/disabling inter-RAT, 3G location area, and 4G tracking area handover restriction lists (MME and S-GW only)
  • setting maximum bearers and PDNs per subscriber (MME and S-GW only)

Call control profiles are configured with commands in the Call Control Profile configuration mode. A single call control profile can be associated with multiple operator policies

For planning purposes, based on the system configuration, type of packet services cards, type of network (2G, 3G, 4G, LTE), and/or application configuration (single, combo, dual access), the following call control profile configuration rules should be considered:
  • 1 (only one) - call control profile can be associated with an operator policy
  • 1000 - maximum number of call control profiles per system (e.g., an SGSN).
  • 15 - maximum number of equivalent PLMNs for 2G and 3G per call control profile
    • 15 - maximum number of equivalent PLMNs for 2G per ccprofile.
    • 15 - maximum number of supported equivalent PLMNs for 3G per ccprofile.
  • 256 - maximum number of static SGSN addresses supported per PLMN
  • 5 - maximum number of location area code lists supported per call control profile.
  • 100 - maximum number of LACs per location area code list supported per call control profile.
  • unlimited number of zone code lists can be configured per call control profile.
  • 100 - maximum number of LACs allowed per zone code list per call control profile.
  • 2 - maximum number of integrity algorithms for 3G per call control profile.
  • 3 - maximum number of encryption algorithms for 3G per call control profile.

APN Profile

An APN profile groups a set of access point name (APN)-specific parameters that may be applicable to one or more APNs. When a subscriber requests an APN that has been identified in a selected operator policy, the parameter values configured in the associated APN profile will be applied.

For example:
  • enable/disable a direct tunnel (DT) per APN. (SGSN)
  • define charging characters for calls associated with a specific APN.
  • identify a specific GGSN to be used for calls associated with a specific APN (SGSN).
  • define various quality of service (QoS) parameters to be applied to calls associated with a specific APN.
  • restrict or allow PDP context activation on the basis of access type for calls associated with a specific APN.

APN profiles are configured with commands in the APN Profile configuration mode. A single APN profile can be associated with multiple operator policies.

For planning purposes, based on the system configuration, type of packet processing cards and 2G, 3G, 4G, and/or dual access, the following APN profile configuration rules should be considered:
  • 50 - maximum number of APN profiles that can be associated with an operator policy.
  • 1000 - maximum number of APN profiles per system (e.g., an SGSN).
  • 116 - maximum gateway addresses (GGSN addresses) that can be defined in a single APN profile.

IMEI-Profile (SGSN only)

The IMEI is a unique international mobile equipment identity number assigned by the manufacturer that is used by the network to identify valid devices. The IMEI has no relationship to the subscriber.

An IMEI profile group is a set of device-specific parameters that control SGSN behavior when one of various types of Requests is received from a UE within a specified IMEI range. These parameters control:
  • Blacklisting devices
  • Identifying a particular GGSN to be used for connections for specified devices
  • Enabling/disabling direct tunnels to be used by devices

IMEI profiles are configured with commands in the IMEI Profile configuration mode. A single IMEI profile can be associated with multiple operator policies.

For planning purposes, based on the system configuration, type of packet processing cards, type of network (2G, 3G, 4G, LTE), and/or application configuration (single, combo, dual access), the following IMEI profile configuration rules should be considered:
  • 10 - maximum number of IMEI ranges that can be associated with an operator policy.
  • 1000 - maximum number of IMEI profiles per system (such as an SGSN).

APN Remap Table

APN remap tables allow an operator to override an APN specified by a user, or the APN selected during the normal APN selection procedure, as specified by 3GPP TS 23.060. This atypical level of control enables operators to deal with situations such as:

  • An APN is provided in the Activation Request that does not match with any of the subscribed APNs either a different APN was entered or the APN could have been misspelled. In such situations, the SGSN would reject the Activation Request. It is possible to correct the APN, creating a valid name so that the Activation Request is not rejected.

  • In some cases, an operator might want to force certain devices/users to use a specific APN. For example, all iPhone4 users may need to be directed to a specific APN. In such situations, the operator needs to be able to override the selected APN.

An APN remap table group is a set of APN-handling configurations that may be applicable to one or more subscribers. When a subscriber requests an APN that has been identified in a selected operator policy, the parameter values configured in the associated APN remap table will be applied. For example, an APN remap table allows configuration of the following:

  • APN aliasing - maps incoming APN to a different APN based on partial string match (MME and SGSN) or matching charging characteristic (MME and SGSN).

  • Wildcard APN - allows APN to be provided by the SGSN when wildcard subscription is present and the user has not requested an APN.

  • Default APN - allows a configured default APN to be used when the requested APN cannot be used for example, the APN is not part of the HLR subscription. In 21.4 and later releases, the configuration to enable default APN on failure of DNS query is enhanced to support S4-SGSN. When wildcard APN is received in subscription, the DNS request is tried with the MS requested APN and on failure of DNS, it is retried with the APN value configured in the APN remap table.

APN remap tables are configured with commands in the APN Remap Table configuration mode. A single APN remap table can be associated with multiple operator policies, but an operator policy can only be associated with a single APN remap table.

For planning purposes, based on the system configuration, type of packet processing cards, type of network (2G, 3G, 4G, LTE), and/or application configuration (single, combo, dual access), the following APN remap table configuration rules should be considered:

  • 1 - maximum number of APN remap tables that can be associated with an operator policy.

  • 1000 - maximum number of APN remap tables per system (such as an SGSN).

  • 100 - maximum remap entries per APN remap table.

Operator Policies

The profiles and tables are created and defined within their own configuration modes to generate sets of rules and instructions that can be reused and assigned to multiple policies. An operator policy binds the various configuration components together. It associates APNs, with APN profiles, with an APN remap table, with a call control profile, and/or an IMEI profile (SGSN only) and associates all the components with filtering ranges of IMSIs.

In this manner, an operator policy manages the application of rules governing the services, facilities, and privileges available to subscribers.

Operator policies are configured and the associations are defined via the commands in the Operator Policy configuration mode.

The IMSI ranges are configured with the command in the SGSN-Global configuration mode.

For planning purposes, based on the system configuration, type of packet processing cards, type of network (2G, 3G, 4G, LTE), and/or application configuration (single, combo, dual access), the following operator policy configuration rules should be considered:
  • 1 maximum number of call control profiles associated with a single operator policy.
  • 1 maximum number of APN remap tables associated with a single operator policy.
  • 10 maximum number of IMEI profiles associated with a single operator policy (SGSN only)
  • 50 maximum number of APN profiles associated with a single operator policy.
  • 1000 maximum number of operator policies per system (e.g., an SGSN) this number includes the single default operator policy.
  • 1000 maximum number of IMSI ranges defined per system (e.g., an SGSN).

Important

SGSN operator policy configurations can be converted to enable them to work with an SGSN. Your Cisco Account Representative can accomplish this conversion for you.

IMSI Ranges

Ranges of international mobile subscriber identity (IMSI) numbers, the unique number identifying a subscriber, are associated with the operator policies and used as the initial filter to determine whether or not any operator policy would be applied to a call. The range configurations are defined by the MNC, MCC, a range of MSINs, and optionally the PLMN ID. The IMSI ranges must be associated with a specific operator policy.

IMSI ranges are defined differently for each product supporting the operator policy feature.

How It Works

The specific operator policy is selected on the basis of the subscriber's IMSI at attach time, and optionally the PLMN ID selected by the subscriber or the RAN node's PLMN ID. Unique, non-overlapping, IMSI + PLMN-ID ranges create call filters that distinguish among the configured operator policies.

The following flowchart maps out the logic applied for the selection of an operator policy:

Figure 1. Operator Policy Selection Logic

Operator Policy Configuration

This section provides a high-level series of steps and the associated configuration examples to configure an operator policy. By configuring an operator policy, the operator fine-tunes any desired restrictions or limitations needed to control call handling per subscriber or for a group of callers within a defined IMSI range.

Most of the operator policy configuration components are common across the range of products supporting operator policy. Differences will be noted as they are encountered below.


Important

This section provides a minimum instruction set to implement operator policy. For this feature to be operational, you must first have completed the system-level configuration as described in the System Administration Guide and the service configuration described in your product's administration guide.

The components can be configured in any order. This example begins with the call control profile:

Procedure

Step 1

Create and configure a call control profile, by applying the example configuration presented in the Call Control Profile Configuration section.

Step 2

Create and configure an APN profile, by applying the example configuration presented in the APN Profile Configuration section.

Note 

It is not necessary to configure both an APN profile and an IMEI profile. You can associate either type of profile with a policy. It is also possible to associate one or more APN profiles with an IMEI profile for an operator policy (SGSN only).

Step 3

Create and configure an IMEI profile by applying the example configuration presented in the IMEI Profile Configuration section (SGSN only).

Step 4

Create and configure an APN remap table by applying the example configuration presented in the APN Remap Table Configuration section.

Step 5

Create and configure an operator policy by applying the example configuration presented in the Operator Policy Configuration section.

Step 6

Configure an IMSI range by selecting and applying the appropriate product-specific example configuration presented in the IMSI Range Configuration sections below.

Step 7

Associate the configured operator policy components with each other and a network service by applying the example configuration in the Operator Policy Component Associations section.

Step 8

Save your configuration to flash memory, an external memory device, and/or a network location using the Exec mode command save configuration . For additional information on how to verify and save configuration files, refer to the System Administration Guide .

Step 9

Verify the configuration for each component separately by following the instructions provided in the Verifying the Feature Configuration section of this chapter.

Call Control Profile Configuration

This section provides the configuration example to create a call control profile and enter the configuration mode.

Use the call control profile commands to define call handling rules that will be applied via an operator policy. Only one call control profile can be associated with an operator policy, so it is necessary to use (and repeat as necessary) the range of commands in this mode to ensure call-handling is sufficiently managed.

Configuring the Call Control Profile for an SGSN

The example below includes some of the more commonly configured call control profile parameters with sample variables that you will replace with your own values. 

configure 
   call-control-profile profile_name> 
      attach allow access-type umts location-area-list instance list_id 
      authenticate attach  
      location-area-list instance instance area-code area_code   
      sgsn-number E164_number  
      end
Notes:
  • Refer to the Call Control Profile Configuration Mode chapter in the Command Line Interface Reference for command details and variable options.
  • This profile will only become valid when it is associated with an operator policy.

Configuring the Call Control Profile for an MME or S-GW

The example below includes some of the more commonly configured call control profile parameters with sample variables that you will replace with your own values. 

configure 
    call-control-profile profile_name 
      associate hss-peer-service service_name  s6a-interface 
      attach imei-query-type imei verify-equipment-identity 
      authenticate attach  
      dns-pgw context mme_context_name  
      dns-sgw context mme_context_name  
      end
Notes:
  • Refer to the Call Control Profile Configuration Mode chapter in the Command Line Interface Reference for command details and variable options.
  • This profile will only become valid when it is associated with an operator policy.

APN Profile Configuration

This section provides the configuration example to create an APN profile and enter the apn-profile configuration mode.

Use the apn-profile commands to define how calls are to be handled when the requests include an APN. More than one APN profile can be associated with an operator policy.

The example below includes some of the more commonly configured profile parameters with sample variables that you will replace with your own values. 

configure 
   apn-profile profile_name 
      gateway-address 209.165.200.227 priority 1(SGSN only) 
      direct-tunnel not-permitted-by-ggsn (SGSN only) 
      idle-mode-acl ipv4 access-group station7 (S-GW only) 
      end
Notes:
  • All of the parameter defining commands in this mode are product-specific. Refer to the APN Profile Configuration Mode chapter in the Command Line Interface Reference for command details and variable options.
  • This profile will only become valid when it is associated with an operator policy.

IMEI Profile Configuration - SGSN only

This section provides the configuration example to create an IMEI profile and enter the imei-profile configuration mode.

Use the imei-profile commands to define how calls are to be handled when the requests include an IMEI in the defined IMEI range. More than one IMEI profile can be associated with an operator policy.

The example below includes some of the more commonly configured profile parameters with sample variables that you will replace with your own values. 

configure 
   imei-profile profile_name 
      ggsn-address 211.211.123.3 
      direct-tunnel not-permitted-by-ggsn (SGSN only) 
      associate apn-remap-table remap1 
      end
Notes:
  • It is optional to configure an IMEI profile. An operator policy can include IMEI profiles and/or APN profiles.
  • This profile will only become valid when it is associated with an operator policy.

APN Remap Table Configuration

This section provides the configuration example to create an APN remap table and enter the apn-remap-table configuration mode.

Use the apn-remap-table commands to define how APNs are to be handled when the requests either do or do not include an APN.

The example below includes some of the more commonly configured profile parameters with sample variables that you will replace with your own values. 

configure 
   apn-remap-table table_name 
      apn-selection-default first-in-subscription 
      wildcard-apn pdp-type ipv4 network-identifier apn_net_id 
      blank-apn network-identifier apn_net_id (SGSN only) 
      end
Notes:
  • The apn-selection-default first-in-subscription command is used for APN redirection to provide "guaranteed connection" in instances where the UE-requested APN does not match the default APN or is missing completely. In this example, the first APN matching the PDP type in the subscription is used. The first-in-selection keyword is an MME feature only.
  • Some of the commands represented in the example above are common and some are product-specific. Refer to the APN-Remap-Table Configuration Mode chapter in the Command Line Interface Reference for command details and variable options.
  • This profile will only become valid when it is associated with an operator policy.

Operator Policy Configuration

This section provides the configuration example to create an operator policy and enter the operator policy configuration mode.

Use the commands in this mode to associate profiles with the policy, to define and associate APNs with the policy, and to define and associate IMEI ranges. Note: IMEI ranges are supported for SGSN only.

The example below includes sample variable that you will replace with your own values. 

configure 
   operator-policy policy_name 
      associate call-control-profile profile_name 
      apn network-identifier apn-net-id_1 apn-profile apn_profile_name_1 
      apn network-identifier apn-net-id_2 apn-profile apn_profile_name_1  
      imei range <imei_number to imei_number imei-profile name profile_name  
      associate apn-remap-table table_name 
      end
Notes:
  • Refer to the Operator-Policy Configuration Mode chapter in the Command Line Interface Reference for command details and variable options.
  • This policy will only become valid when it is associated with one or more IMSI ranges (SGSN) or subscriber maps (MME and S-GW).

IMSI Range Configuration

This section provides IMSI range configuration examples for each of the products that support operator policy functionality.

Configuring IMSI Ranges on the MME or S-GW

IMSI ranges on an MME or S-GW are configured in the Subscriber Map Configuration Mode. Use the following example to configure IMSI ranges on an MME or S-GW: 

configure 
   subscriber-map name 
      lte-policy 
         precedence number match-criteria imsi mcc mcc_number mnc mnc_number msin first start_range last end_range operator-policy-name policy_name 
         end
Notes:
  • The precedence number specifies the order in which the subscriber map is used. 1 has the highest precedence.
  • The operator policy name identifies the operator policy that will be used for subscribers that match the IMSI criteria and fall into the MSIN range.

Configuring IMSI Ranges on the SGSN

The example below is specific to the SGSN and includes sample variables that you will replace with your own values. 

configure 
   sgsn-global 
      imsi-range mcc 311 mnc 411 operator-policy oppolicy1  
      imsi-range mcc 312 mnc 412 operator-policy oppolicy2  
      imsi-range mcc 313 mnc 413 operator-policy oppolicy3  
      imsi-range mcc 314 mnc 414 operator-policy oppolicy4  
      imsi-range mcc 315 mnc 415 operator-policy oppolicy5  
      end
Notes:
  • Operator policies are not valid until IMSI ranges are associated with them.

Associating Operator Policy Components on the MME

After configuring the various components of an operator policy, each component must be associated with the other components and, ultimately, with a network service.

The MME service associates itself with a subscriber map. From the subscriber map, which also contains the IMSI ranges, operator policies are accessed. From the operator policy, APN remap tables and call control profiles are accessed.

Use the following example to configure operator policy component associations: 

configure 
   operator-policy name 
      associate apn-remap-table table_name 
      associate call-control-profile profile_name 
      exit 
   lte-policy 
      subscriber-map name 
         precedence match-criteria all operator-policy-name policy_name 
         exit 
      exit 
   context mme_context_name 
      mme-service mme_svc_name 
         associate subscriber-map name 
         end
Notes:
  • The precedence command in the subscriber map mode has other match-criteria types. The all type is used in this example.

Configuring Accounting Mode for S-GW

The accounting mode command configures the mode to be used for the S-GW service for accounting, either GTPP (default), RADIUS/Diameter, or None.

Use the following example to change the S-GW accounting mode from GTPP (the default) to RADIUS/Diameter: 

configure 
   context sgw_context_name 
      sgw-service sgw_srv_name 
         accounting mode radius-diameter 
         end
Notes:
  • An accounting mode configured for the call control profile will override this setting.

Verifying the Feature Configuration

This section explains how to display the configurations after saving them in a .cfg file as described in the System Administration Guide.


Important

All commands listed here are under Exec mode. Not all commands are available on all platforms.

Procedure

Verify that the operator policy has been created and that required profiles have been associated and configured properly by entering the following command in Exec Mode: 

show operator-policy full name oppolicy1

The output of this command displays the entire configuration for the operator policy configuration. 

show operator-policy full name oppolicy1 
Operator Policy Name = oppolicy1 
Call Control Profile Name                    : ccprofile1 
   Validity                                  : Valid 
APN Remap Table Name                         : remap1 
   Validity                                  : Valid 
IMEI Range 711919739      to       711919777 
   IMEI Profile Name                         : imeiprof1 
      Include/Exclude                        : Include 
        Validity                             : Valid 
APN NI homers1 
   APN Profile Name                          : apn-profile1 
      Validity                               : Valid

Notes:

  • If the profile name is shown as "Valid", the profile has actually been created and associated with the policy. If the Profile name is shown as "Invalid", the profile has not been created/configured.
  • If there is a valid call control profile, a valid APN profile and/or valid IMEI profile, and a valid APN remap table, the operator policy is valid and complete if the IMSI range has been defined and associated.