HLR Lookup has two primary applications: low volume message routing and number validation. 

To be useful, fundamental service issues must be overcome by providers.  Other use cases exist although it is difficult to offer these services consistently and lawfully across multiple jurisdictions. 

Routing optimisation for A2P messaging

In most markets, termination fees incur a surcharge if the received traffic is off-net (i.e. a subscriber doesn’t belong to the terminating network and requires forwarding to the correct network). In other markets, off-net messages can simply be dropped. To assure that messages are delivered in a timely manner and margins are optimised, A2P SMS aggregators check number portability records in real-time prior to attempting on-net message delivery (directly to the subscriber’s network).

In the past, the go-to tool for number portability was HLR Lookup, but such services don’t scale well and provide inconsistent results. Most A2P SMS aggregators have migrated to using dedicated number portability services which combine HLR Lookup, Number Range and MNP databases. HLR Lookup remains as the only viable tool for routing in low volume application with a high likelihood of intraday porting.

MNP by XConnect

Data quality management for CRM

Most enterprises place a high value on the accuracy of their customers’ telephone numbers.  Managing data quality can include validating customer lead forms in real-time, filtering out fixed line numbers prior to executing an SMS messaging campaign, or regularly performing data cleansing activities.  HLR Lookup is an important technique for basic number validation.  XConnect’s NPQ-Live service is powered by XConnect’s Number Range service as well as access to market leading HLR Lookup network providers.  HLR Lookup also powers XConnect’s advanced Number Validation service.

MNP by XConnect

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MNP by XConnect
Feature XConnect’s NPQ-Live Other HLR Lookup Providers

Routing Information

Amongst other attributes, an HLR Lookup returns the International Mobile Subscriber Identifier (IMSI) which relates to the telephone number.  This identifier is made up of 15 digits, the first 5 digits contain the mobile country code (MCC) and mobile network code (MNC) which are used to enable routing of traffic to the subscriber.

The lookup returns information that is contained in a network operators HLR at the time of the lookup.  Some HLR Lookup providers return results from their local cache which can be different to that stored in the HLR.

Yes Yes

Basic Validation Information 

HLR Lookup has been used for many years to clean telephone number lists.  When the lookup returns an IMSI, it provides certainty that the telephone number is allocated to a network provider.  However, HLR Lookup coverage can be very inconsistent and when used in validation applications can return a large number of false negatives.

More advanced and more cost effective validation solutions exists such as XConnect’s Number Validation service (VAR).

Yes Yes

Subscriber Information Blocking 

A full HLR Lookup response returns information including Roaming Status, Roamed Country and Subscriber Status.  These are highly sensitive personal attributes that can have legally significant consequences on individuals.  In most instances network operators block these attributes from being available to third parties in order to comply with consumer protection and privacy legislation.  

Some HLR Lookup providers pass on any attributes they receive regardless of any privacy and subscriber risk.  XConnect’s NPQ-Live service strictly controls access sensitive attributes through a privacy-by-design approach in order to maximise service trust and offer a consistent global service.

Yes Some

IMSI Masking 

The Mobile Subscriber Identity Number (MSIN) is the last 9 digits of the IMSI.  The MSIN uniquely identifies the SIM card installed in a mobile device.  Most operators have blocked access to the MSIN due to security and identity theft vulnerabilities (see blog, The Security of SMS One Time Passwords).

Some HLR Lookup vendors return the MSIN.  Many incorrectly claiming it to be valid or failing to implement appropriate checks to ensure that end to end services are appropriate.  Detecting a change in MSIN can indicate is the SIM card has been changed, which could have occurred illegally (see Account Takeover Protection for more information).

XConnect strictly controls access to MSIN information through a privacy-by-design approach in order to maximise service trust and offer a consistent global service.

Yes Some

Managed Coverage

HLR Lookup providers have access to a limited set of network operators.  This access can be subject to change without notice due to the firewall and filtering techniques deployed by mobile operators to protect their networks and subscribers. 

Obtaining complete country access and global coverage requires aggregation of services at a network operator level and a method to proactively test access on a daily basis so as to ensure the best coverage and consistency.  

Yes No

Low Latency 

HLR Lookups came to market as a by-product of A2P SMS messaging but were never designed to support the performance needs of high volume messaging applications or international voice interconnect.  In general, latency is unacceptably high, taking anywhere from 350 to 2000 milliseconds.  Such delays can cause huge message processing bottlenecks resulting in poor customer experiences.  Message routing applications, such as XConnect’s Number Portability Service (NPQ), exist to overcome these limitations working up to 1000 times faster.

No (see NPQ) No

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