Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!HPLB.HPL.HP.COM!rhc
From: rhc@HPLB.HPL.HP.COM (Robert Cole)
Newsgroups: comp.protocols.iso
Subject: Re: Performance Metrics
Message-ID: <8905052232.AA21243@ucbvax.Berkeley.EDU>
Date: 4 May 89 09:31:15 GMT
References: <11789.8904281324@pyr.swan.ac.uk>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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> I am currently involved in a British Standards exercise looking at
> Time Critical Communication Architectures (TCCA) in the context of
> the OSI reference model. We are currently examining metrics for network 
> performance so that users may have some tools to use in the choice of
> or configuration of time critical networks.

> We find the current means of quantifying performance (ie. octects per
> second through layers etc.) to be rather unsuitable for our purposes. I
> have seen some discussion on the list about the optimization of ASN.1
> encoding and the metrics used for that purpose. My questions are...

>  - Have any metrics for the performance of layered protocols been 
>    defined in the time domain;   

>  - Are any other groups addressing this problem;

> We are interested in any input in this area and are particularly 
> concerned that we do not replicate any effort already expended in 
> this area.

> Any assistance/information would be most welcome.

Ivan,
I am interested in your project.

I am currently thinking about the problems of moving a time
synchronisation protocol over to OSI. The protocol runs on the DARPA
Internet where it uses the datagram service. The protocol relies on
the round trip time being fairly constant. That is, only delays due to
queueing should afect the round trip time. When moving over to OSI it
seems that the connection oriented protocols at each layer are not
only going to interfere with each other, but any retransmissions due
to lost packets at lower layers will cause severe disrupton to the
round trip time varience.

Is your project looking at this type of application?

Robert.