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what the hell are SIM cards for? SIM cards are for binding IMSI/MSISDN/IMEI, to authenticate you to the mobile network and update the HLR with your location.

what the hell are SIM cards for? SIM cards are for binding IMSI/MSISDN/IMEI, to authenticate you to the mobile network and update the HLR with your location. This data also traverses the SS7 network but does contain some authentication data specific to the wireless provider. The landline telcos have no knowledge of what this data means beyond the ability to route it. The mobile switches will route your MSISDN to the other SS7 networks. accurate caller ID attached by the carrier This goes back to the suggested shaken/stir method of authentication. There is really no other way to determine what is valid and what is not. The carrier can attach nearly any number and that number can be entirely valid.

wtallis 6y ago
Again, what the hell are SIM cards for? Skip the alphabet soup, please. On some level, a SIM card must authenticate you to the local tower operator as authorized to place calls, and identify what other carrier gets billed for that if you're roaming. They also identify (in an authenticated manner) what the phone number is for your cell phone, so that the local tower operator can start routing calls to that number to your handset. This seems sufficient for the local tower operator to ensure that you aren't using your smartphone to place tons of robocalls with spoofed numbers, using only infrastructure that is already universally implemented. I don't see where a landline telco on the receiving end of calls originating from your smartphone needs to know anything about any of that process; the mobile network operator that's connecting the first hop of your call can be and should be the one responsible for preventing you from abusing the network. I want my phone company to hold the mobile network to that standard before letting calls from that network make my phone ring. > This goes back to the suggested shaken/stir method of authentication. There is really no other way to determine what is valid and what is not. The carrier can attach nearly any number and that number can be entirely valid. This sounds again like you're deciding ahead of time that the problem can only be addressed by a technical solution that turns out to be basically intractable. You're saying that solving the spoofed robocall problem requires every telco to be able to fully validate in realtime who owns what number and is roaming where. I'm pointing out a relatively non-technical solution where each network is only responsible for restricting the bullshit the let into their network, at the boundaries where it seems practical to enforce without overhauling the entire protocol stack for the whole industry. And lax enforcement would get a carrier blacklisted, or at least make all calls originating from their network readily identifiable as suspicious and trivially blockable.
- LinuxBender 6y ago
  What I am saying is that mobile networks don't share any of this data with telcos. To do so would require overhauling the landline networks to support this. No such technical capabilities exist today. The business decision you are suggesting could not be implemented even if they wanted to. Mobile networks are another implementation of SS7 and the only thing common between them and landline networks is the routing. I am not deciding anything and I am just basing my opinions on my long past experience.
  - wtallis 6y ago
    > What I am saying is that mobile networks don't share any of this data with telcos. I'm not asking for any new data to be shared from mobile networks to landline telcos. You haven't explained why you think that is required in order for mobile networks to perform sanity checking (or sanitization) on the data they're already sending to other telcos during call setup.

wtallis 6y ago

Again, what the hell are SIM cards for? Skip the alphabet soup, please. On some level, a SIM card must authenticate you to the local tower operator as authorized to place calls, and identify what other carrier gets billed for that if you're roaming. They also identify (in an authenticated manner) what the phone number is for your cell phone, so that the local tower operator can start routing calls to that number to your handset. This seems sufficient for the local tower operator to ensure that you aren't using your smartphone to place tons of robocalls with spoofed numbers, using only infrastructure that is already universally implemented. I don't see where a landline telco on the receiving end of calls originating from your smartphone needs to know anything about any of that process; the mobile network operator that's connecting the first hop of your call can be and should be the one responsible for preventing you from abusing the network. I want my phone company to hold the mobile network to that standard before letting calls from that network make my phone ring. > This goes back to the suggested shaken/stir method of authentication. There is really no other way to determine what is valid and what is not. The carrier can attach nearly any number and that number can be entirely valid. This sounds again like you're deciding ahead of time that the problem can only be addressed by a technical solution that turns out to be basically intractable. You're saying that solving the spoofed robocall problem requires every telco to be able to fully validate in realtime who owns what number and is roaming where. I'm pointing out a relatively non-technical solution where each network is only responsible for restricting the bullshit the let into their network, at the boundaries where it seems practical to enforce without overhauling the entire protocol stack for the whole industry. And lax enforcement would get a carrier blacklisted, or at least make all calls originating from their network readily identifiable as suspicious and trivially blockable.

LinuxBender 6y ago
What I am saying is that mobile networks don't share any of this data with telcos. To do so would require overhauling the landline networks to support this. No such technical capabilities exist today. The business decision you are suggesting could not be implemented even if they wanted to. Mobile networks are another implementation of SS7 and the only thing common between them and landline networks is the routing. I am not deciding anything and I am just basing my opinions on my long past experience.
- wtallis 6y ago
  > What I am saying is that mobile networks don't share any of this data with telcos. I'm not asking for any new data to be shared from mobile networks to landline telcos. You haven't explained why you think that is required in order for mobile networks to perform sanity checking (or sanitization) on the data they're already sending to other telcos during call setup.