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by PinguTS
4302 days ago
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That is not right, that ATM failed to see real world usage. ATM was the backbone of the German infrastructure run mainly by German Telekom for years. It provided a very good service especially for telephony (ISDN). Germany basically had the best telephony network in the world. But the problem is, that IP does not fit with the 55ms time slot in ATM. That is the why all the backbones are replaced with the so-called Next Generation Networks (NGN), which basically is pure IP traffic and everything will be on top of IP, not anymore in parallel to IP. That basically means, moving to VoIP in the backbone and consequently also for the consumer end. |
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ATM is essentially circuit-switched technology lying somewhere between L1 and L2 that allows for efficient QoS for different services sharing same wire at the expense of ludicrous framing overhead and creating networks of such channels with reasonably simple and fast switches. The QoS part is mostly irrelevant today as faster interfaces made the problem significantly easier to solve so is the simple and fast switching. ATM's orientation towards end-to-end circuit-switched channels is what allows fast switches but also requires some external control-plane that builds and tears down the virtual channels, which I think is the major reason why ATM (and OSI in general) didn't catch on, on IP, you just send packet with destination address down the wire, with ATM you have to establish connection first (by using something essentially out-of-band and centralized).
In the end, ATM is widely used today, but mostly as pre-existing way of handling QoS and framing on top of some unrelated but relatively slow L1 technology (ATM is the first higher-level layer of both UMTS and xDSL)