Messente avatar logo

Home Location Register (HLR) & Visitor Location Register (VLR)

- 5 MIN READ - 20 May 2015

A significant part in delivering SMS messages is receiving delivery information. Apart from the basic delivery report, there are protocols that help us to identify the status of a phone number more precisely.

So what is HLR and VLR?

The Home Location Register, aka HLR, is a mobile operator database that includes details of subscribers, such as the phone number, billing details, and phone status parameters that are valuable if an SMS didn't get delivered. This data is accessible by all Mobile Switching Centres (MSC) and Visiting Location Registers (VLR).

Essential parameters in the HLR are:
  1. Phone number
  2. Current network location
  3. Supplementary Services
  4. Number status (registered or deregistered)
  5. Authentication key and AUC Functionality
  6. Mobile subscriber roaming number
The Visiting Location Register supports roaming functions for users outside the coverage area of their own HLR. It contains mostly the same data from the HLR, yet this information is stored temporarily, containing mostly duplicated information relevant to the subscriber network location.  As a phone number may operate outside their home network at times,  the VLR can locate in which network the number is currently roaming.

VLR helps to:
  1. Monitor subscribers’ locations within the VLR’s jurisdiction
  2. Determine whether a subscriber may access a particular service
  3. Locate roaming numbers during incoming SMS
  4. Delete the records of inactive subscribers
  5. Accept information passed to it by the HLR
When sending SMS messages, the operator initially checks whether the number is sending and receiving signals from the its home network. If it's not in the home network, the VLR sends a request for information about its current status and location by network via HLR. The VLR sends routing information back to the Mobile Switching Center, which allows it to locate the network it’s currently roaming to deliver the message. This communication is based on Signaling System (SS7) protocols and signaling.

The main difference between HLR and VLR is the data that is stored in them. HLR has more permanent data while VLR’s data changes all the time and is temporary.

Essential parameters in the VLR are:
  1. Location Area Identity (LAI)
  2. Temporary Mobile Subscriber Identity (TMSI)
  3. Mobile Station Roaming Number (MSRN)
  4. Mobile status

Margus Sütt

Margus Sütt - Key account manager

Margus works as a business analyst at Messente. Identifying new opportunities and going deep into industries Margus consults Messente's key customers to help their businesses to advance.

How we help with the regulations of global messaging

26 Jun 2017

Forgoing the need to integrate network operators everywhere you need messages delivered is one of the main advantages of using a global messaging platform. Each connection includes legalities, which includes reviewing several agreements and negotiating terms, and technical tasks, like setting up the connections. So, a single company going through this process on their own would invest a lot of time doing things that have already been done by a messaging platform. Also, the company would end up with higher pricing from network operators, as it has much less traffic.

Lauri Kinkar

Lauri Kinkar

Your sales lab time is scarce

20 Jun 2017

In the series about sales research, I touched upon allocating about 30% of your research time on finding new ideas and possibilities around sales tactics. But how do you actually do it and what do you look for?

Uku Tomikas

Uku Tomikas

An open letter to financial institutions from Yuriy

09 Jun 2017

To the bank, credit card company, and investment firm I work with: I trust you. I really do.

If I didn’t, I wouldn’t put my hard-earned money in your hands. While I’m not a Certified Financial Analyst, I am financially savvy, so I understand that we have a mutually beneficial relationship. From a high-level, banks use the money I deposit to sell loans and invest in other financial instruments. Credit card companies make money on interest charges, other fees, and transaction fees from merchants. The brokerage firm makes money through fees on my account. On the other hand, all I expect is that you are honest about your services, provide returns, and keep my money safe.

Yuriy Mikitchenko

Yuriy Mikitchenko

Start sending messages to

for € N/A

Contact us