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I'm seeing a lot of posts reference lar_disable like this one for instance. I'm wondering what it does. modinfo iwlwifi just says,

parm:           lar_disable:disable LAR functionality (default: N) (bool)

What is "LAR functionality"?

Evan Carroll
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    If you don't know what it does, then disable it and if it is useful, you will notice it. – Rolf Mar 22 '19 at 14:14

3 Answers3

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LAR means Location Aware Regulatory

I searched LAR in the source code of Linux wireless driver, only Intel use the LAR term in their code. In their code comment [1, 2, 3] mention the full form of LAR

Comzyh
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LAR functionality for WIFI modules is not connected to Location-Aided Routing, but Location-Aware Regulatory. Let me disambiguate those two terms.

Location-Aided Routing

decides how to send you packets in the fastest way and shortest distance in Ad-Hoc networks, i.e. IoT (Internet of Things) or other on-location usages, such as army or emergency response units.

Location-Aware Regulatory

gives a country code to your wifi module on automatic basis based on the location you are in (European Union states have different regulations from US or China for radiation, mainly in 5GHz band). It was possible to turn it off previously, using the lar_disable parameter, although it was removed somewhere around 2019/2020, so now the country code is only set automatically and there is almost nothing you can do about it, mostly within INTEL cards. Qualcomm, Realtek and all those other guys should not, as of now 2023, force onto you the country's regulation using the country code. You see iwlwifi is Linux' driver for Intel Wireless WiFi. See this link.

Andrej Kružliak
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    Great answer and welcome to the site, when you say "now the country code is only set automatically and there is almost nothing you can do about it," it's not clear what is setting it automatically -- the manufacturer in hardware, software? – Evan Carroll Sep 08 '23 at 15:39
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    It's also not clear when you say, "gives a country code to your wifi module on automatic basis based on the location you are in" how "automatic" works there? Does this get programmed by the OEM? – Evan Carroll Sep 08 '23 at 15:41
  • Hi @EvanCarroll, as far as I know, the regulatory domain 00 is baked into the Intel cards directly. I.e. in the chipset memory. Therefore anything built on top of that cannot do changes. The regulatory domain is somehow (I don't precisely know how) is passed through the ISP (internet service provider). This is a problem, because if you have only one wifi card connected to the internet, when you wanna create 5GHz AP (Access Point) without ethernet cable as input of the internet, the wifi card by Intel drops from known regulatory domain (US for example) to 00 and hence you cannot transmitt. – Andrej Kružliak Oct 24 '23 at 09:05
  • The 00 is the basic regulatory domain where 5GHz is forbidden (no IR) - no initiate radiation. If you get other regulatory domain information from your ISP by cable or other router, you should be able (although it sometimes doesn't work, multiple different Intel models had set regulatory domain to different countries, IDK why) to get correct regulatory domain. But once your card does not access the WWW, you don't see the country regulatory domain, therefore it falls to 00. I had this problem where I wanted a robot to have 5G AP for control, instead of crowded 2.4GHz. Solved by buying USB wifi – Andrej Kružliak Oct 24 '23 at 09:09
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LAR functionality is a reference to Location-Aided Routing Protocols.

Example papers:

  1. Location-Aided Routing (LAR) in Mobile Ad Hoc Networks
  2. Secure Location-Aided Routing Protocols With Wi-Fi Direct For Vehicular Ad Hoc Networks
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StandardEyre
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