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Exactly. More specifically, Internet servers in data centers connected themselves to the IP network, not the phone network (not surprisingly), so they almost al

Exactly. More specifically, Internet servers in data centers connected themselves to the IP network, not the phone network (not surprisingly), so they almost always had an uplink significantly faster than 56 Kb/s. And the analog local loop had encodings that could transmit at 56 Kb/s. But these encodings were not compatible with the analog-digital conversion used in phone network backbone. While today you'd probably expect that the IP network could connect to every phone branch office where the local loops were connected to the phone network, that wasn't necessarily the case - Internet data would usually have to travel some of its way over the phone network backbone, with the problematic digital encodings. V.90 and related standards allowed the phone network to accept the digital data directly from ISPs and send it in digital form to the branch office, without attempting a digital to analog to digital conversion to inject it as digital voice into the phone network. That's why the upload speed couldn't be improved via this method - it would still need to undergo analog-digital conversion to travel across the phone network to the ISP where it could enter the IP network. (V.92, a later standard, improved upload speed to 48 Kb/s via fancier signal processing trickery that could survive the digital voice conversion.)

hylaride 2y ago
All the early metropolitan or long-haul fiber (mostly SONET) networks were digital aggregations of various circuit-modes (DS*) in those days. It made sense since the phone network was pretty much the only long haul network around and even the pure-IP networks didn't yet have enough of a market for alternative protocols. I've been out of the core-networking loop for awhile, but my understanding is that most modern long-haul networks are ethernet over OTN. The phone companies had enormous sway over the development of these longer haul protocols. The debate around packet sizing almost always favoured smaller cells (especially ATM), which was more ideal for voice - with the added overhead for more standard IP packets. They were also often very connection-oriented, with all the extra equipment overhead required.
- immibis 2y ago
  Circuits meant for IP didn't convert digital to analog and back unless they had to share the line with a phone at one end. If you had digital connections to both ends of a digital circuit, you'd use all the bits for data.
  - hylaride 2y ago
    I'm a little confused - I didn't say that? I said that a lot of the circuits meant for IP still had to use (digital) protocols designed for voice.

hylaride 2y ago

All the early metropolitan or long-haul fiber (mostly SONET) networks were digital aggregations of various circuit-modes (DS*) in those days. It made sense since the phone network was pretty much the only long haul network around and even the pure-IP networks didn't yet have enough of a market for alternative protocols. I've been out of the core-networking loop for awhile, but my understanding is that most modern long-haul networks are ethernet over OTN. The phone companies had enormous sway over the development of these longer haul protocols. The debate around packet sizing almost always favoured smaller cells (especially ATM), which was more ideal for voice - with the added overhead for more standard IP packets. They were also often very connection-oriented, with all the extra equipment overhead required.

immibis 2y ago
Circuits meant for IP didn't convert digital to analog and back unless they had to share the line with a phone at one end. If you had digital connections to both ends of a digital circuit, you'd use all the bits for data.
- hylaride 2y ago
  I'm a little confused - I didn't say that? I said that a lot of the circuits meant for IP still had to use (digital) protocols designed for voice.