Let me add one more word to this discussion. In case of simple and solid FDDI or Ethernet protocol it's not big chance if the whole switch would be failed down by one crazy interface card or one crazy router. In case of ATM nobody can protect the whole ATM system from being failed down due to some software bug since 1 / 5 after system was installed, because the number of different featires in ATM network and ATM interface is more then 10 - 100 times more in comparasion with FDDI. This means - if your FDDI switch works fine just now, it's more than 99% it'll work next 2 years (may be it'll be saturated but would not crash totally); in case of ATM it's more than 20% the whole system would be crashed by some new neighboar with some new ATM software... It's not my experience, but one of our partners are debbugging simple direct ATM link just about 3 months - there is 3 vendors (ATM provider, ATM's provider vendor, CISCO) and it's not possible to determine why this link loss more than 50% of packets sometimes. This is due to ATM is too complex system... --- Aleksei Roudnev, Network Operations Center, Relcom, Moscow (+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 239-10-10, N 13729 (pager) (+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)