3 ms·

There are various ways to identify the type of connection that is being made. The most straightforward way for the service provider to block some traffic is to

There are various ways to identify the type of connection that is being made. The most straightforward way for the service provider to block some traffic is to put in place a firewall rule that blocks specific protocol/port number combinations. This won't work if WhatsApp were to use HTTPS on port 443 because then the call would look identical to regular web traffic. Another possibility is related to the fact Meta is likely cooperating in the data bundle scheme. So it might be that WhatsApp is intentionally sending a specific signal of some kind that Econet can use to determine what each connection is for. There is a good overview of some of the possible methods on Wikipedia, for example: https://en.wikipedia.org/wiki/Deep_content_inspection https://en.wikipedia.org/wiki/Deep_content_inspection

toast0 2y ago
In the before times, I ran the engineering side of WhatsApp's special pricing / zero rating program. Things may have changed a bit since then, and there's some stuff I heard about but never got the details on. A couple notes: a) Several carriers offered programs without connecting up with us. AFAIK, that's the case for the airline free messaging programs. I've never been sufficiently motivated to do packet traces while in an airplane, but it could be interesting to try to figure out what they're doing. b) there is (or was) support from WA for carriers to do special pricing for messaging (including multimedia) separate from real time (voice/video calls). When I was doing this, this was primarily done by having different address pools for messaging and voip relay servers. p2p voip makes it harder to special price and I don't know how that's handled (but in this case --- the carrier seems to be only allowing traffic for messaging, so p2p voip doesn't need to be specifically matched) c) it's not that hard to look at a packet trace and see what's what anyway. chat isn't TLS, multimedia is, calling is different too. Even if everything looked like TLS, packet spacing and sizes will make the usage clear. Chat is going to be a lot fewer packets, many of them small, and irregularly spaced. Multimedia is going to be an initial clump of packets and then ack clocked; mostly full sized packets. You can't really change the nature of calling packets to look like one of the others without compromising quality of the call. d) I personally really enjoyed seeing advertisements for WhatsApp Twitter Facebook plans, but corporate wasn't as happy about carriers advertising WTF plans ;)
- 20after4 2y ago
  Thanks for clarifying these details! Obviously much better than my pure speculation, though I'm not sure why I got downvoted for it.

toast0 2y ago

In the before times, I ran the engineering side of WhatsApp's special pricing / zero rating program. Things may have changed a bit since then, and there's some stuff I heard about but never got the details on. A couple notes: a) Several carriers offered programs without connecting up with us. AFAIK, that's the case for the airline free messaging programs. I've never been sufficiently motivated to do packet traces while in an airplane, but it could be interesting to try to figure out what they're doing. b) there is (or was) support from WA for carriers to do special pricing for messaging (including multimedia) separate from real time (voice/video calls). When I was doing this, this was primarily done by having different address pools for messaging and voip relay servers. p2p voip makes it harder to special price and I don't know how that's handled (but in this case --- the carrier seems to be only allowing traffic for messaging, so p2p voip doesn't need to be specifically matched) c) it's not that hard to look at a packet trace and see what's what anyway. chat isn't TLS, multimedia is, calling is different too. Even if everything looked like TLS, packet spacing and sizes will make the usage clear. Chat is going to be a lot fewer packets, many of them small, and irregularly spaced. Multimedia is going to be an initial clump of packets and then ack clocked; mostly full sized packets. You can't really change the nature of calling packets to look like one of the others without compromising quality of the call. d) I personally really enjoyed seeing advertisements for WhatsApp Twitter Facebook plans, but corporate wasn't as happy about carriers advertising WTF plans ;)

20after4 2y ago
Thanks for clarifying these details! Obviously much better than my pure speculation, though I'm not sure why I got downvoted for it.