Re: Virtual Circuit protocols => universal access

Karl Auerbach (karl@cavebear.com)
Thu, 25 Aug 94 08:03:05 PDT


> >What about a reliable, connectionless protocol, like ARDP? (Well, it's
> >not really any more or less connectionless than TCP, but there is no
> >connection establishment overhead in ARDP).
>
> Maybe the connection overhead concerns can be solved another way such
> as with MGET, lookahead, smarter caching etc. ?
>
> On the otherhand, it might be reasonable to implement HEAD with a datagram
> if that would help.

(This kind of stuff tends to be discussed on the www-speed list.)

That might help a little bit, but it means putting timers and
retransmit logic in the client.

But my observations indicate that transfer delay and rate are governed
quite a bit more by TCP connection time and the progression through
its slow start algorithms.

FYI...

Just a data point -- two DEC Alpha boxes (i.e. relatively fast
engines), one with a the NCSA server and the other with mosaic. They
each have short, direct 155Mbit paths to a dedicated ATM switch.

In other words, this setup has significant CPU and bandwith resources.

And the time to fetch documents wasn't significantly faster than on an
Ethernet.

--karl--