In addition to reading new material, I enjoy reading older networking books in attempt to see where we've come from and possibly where we're going. Currently, I'm reading a book called Cisco LAN switching, which was published in 1999 as part of the CCIE Professional Development series. The book talks quite a bit about using ATM in network backbones, and it occurred to me that I rarely see anything about ATM anymore in today's network engineering.

Is ATM used anymore or has it mostly been replaced with other technologies at this point in time?

  • ATM is not a transport protocol, it is a physical/data-link protocol. The transport protocols are things like TCP, UDP, SCTP, DCCP, etc.
    – Ron Maupin
    Aug 4, 2023 at 15:45

1 Answer 1


It is still used a bit, but most providers are phasing it out.

  • 1
    Most DSL (gshdsl, adsl flavors) is still on ATM, EFM is comparatively new. But ATM as core is getting rare, we have only very few NNIs to other operators with ATM and hopefully in 3 years time none.
    – ytti
    Jun 10, 2013 at 22:16
  • PTM - Packet Transport Mode. Common for VDSL. And used in AT&T's hacked up Uverse ADSL2+ setup. ("hack" because they're the only one's with a firmware that'll do it.)
    – Ricky
    Jun 10, 2013 at 22:33
  • What technologies are they phasing it out for? MPLS?
    – WaxTrax
    Jun 11, 2013 at 10:46
  • 1
    @WaxTrax whatever flavour the provider wants. MPLS is indeed one of the big candidates.
    – Bulki
    Jun 11, 2013 at 10:53
  • Yeah weirdly MPLS is indeed quite right answer, even though MPLS is not at same layer. Very strictly speaking Ethernet is replacing ATM, but in practice ATM like 'l2 circuits' are build on top of the ethernet with MPLS.
    – ytti
    Jun 11, 2013 at 14:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.