I think it's actually pretty easy to make the case that a
circuit-switched protocol with a sliding window is superior to a
stop-and-wait system that required the RFNM from the receiver before
every message. In that sense, X.25 was an upgrade over the ARPANET. One
problem with coax-based Ethernet was the absence of flow control, which
caused bad things to happen to the Internet when IMPs were replaced by
Ethernets.
RB
On 9/15/2010 12:04 PM, Bob Hinden wrote:
On Sep 14, 2010, at 5:08 PM, Richard Bennett wrote:
I wonder how many people realize that X.25 was a direct descendant of ARPANET, and
that BB&N became a leading supplier of X.25 hardware simply by continuing the
IMP down its evolutionary path.
I was at BBN at the time this was going on. BBN implemented X.25 because it needed a
"standardized" interface to the network instead of BBN's proprietary 1822 interface and
choose X.25. X.25 was developed in parallel to the Arpanet and I disagree that it "was a
direct descendant of ARPANET". It has a very different interface (connection oriented vs.
message oriented) that IMHO was not an improvement.
Bob
p.s. I suggest that BBN use Ethernet instead but that didn't get any traction.
I am pretty sure the world would be different had they followed my suggestion.
--
Richard Bennett
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