links on the blink (fwd)

Subject: Re: links on the blink (fwd)
Date: Mon, 06 Nov 1995 00:21:09 -0800
From: Paul A Vixie <>
[praise of the DEC GIGAswitch deleted...]
... and further,
they now sell an ATM version of the GIGAswitch in case you don't want FDDI
but you need an ATM with working congestion control.)

Contact your DEC sales representative to verify these details, but:

o The GIGAswitch FDDI switch has an OC-3c ATM interface. However,
  the last I knew it could only be used to communicate with another
  GIGAswitches. In other words, it could connect with another
  GIGAswitch, perhaps through an ATM network, but it could not
  connect to, for example, an ATM host. When I looked at this,
  it supported only PVCs, although SVC support was planned.

o DEC productized the AN2 ATM switch, and gave it a confusing
  name something like GIGAswitch ATM. The AN2/GIGAswitch ATM has
  basically nothing in common with the GIGAswitch FDDI switch.

  The AN2 implements a credit-based congestion control mechanism.
  The ATM Forum adopted, after long debate, a rate-based
  congestion control mechanism.

In my opinion:

o The GIGAswitch FDDI switch is a great box.

o The GIGAswitch ATM switch is one of a number of switches which
  ought to be examined when selecting an ATM switch.