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Re: tc syntax for data rates



On Wed, 14 Jun 2000, jamal wrote:

> This is true. I suppose its the opposite of what hard-disk manufacturers
> tell you  when you buy a disk from them ;->

	Heh, the funny thing is this is exactly the same type item.
HD manufs apply *1000 measurements to *1024 units, in this case tc
applies *1024 measurements to *1000 units... :)

> If you are asking if its wrong, i dont know.

	I can see there are reasons to use computer storage units.  
*However*, using these same values for line rates, that are measured
differently, without even a note mentioning the need to convert is
wrong.

> One way to work around it is to enter the correct value that will come out
> to be computed as  1250000 bytes per second; the other way is to
> introduce a new extension "MBIT"? that will do this for you.

	The problem is you end up with entering

	bandwidth 100000000bps
instead of
	bandwidth 100Mbit

	Gets kinda hard keeping all those zeros straight, and in any
case an undocumented work-around to get correct rates in such a great
system is a very broken thing.  I love the system, just about every
router I have is using it, and I can understand how it was written
this way, but the fact I have never even gotten a response to my
questions about *why* it is this way is irksome.  Not even a, "We know
it *seems* broken, but this is why it is not..."


	Data rates on transmission lines are in bits, as in kilo,
mega, giga, tera.

	However, this is as in kilohertz, megahertz, gigahertz,
terahertz.
	1,000Hz
	1,000,000Hz
	1,000,000,000Hz
	1,000,000,000,000Hz


	I don't know what the final syntax should be, but right now
saying bandwidth 100Mbit on a 100Mbit ethernet is *wrong*, a 100Mbit
ethernet has a data rate of 1,000,000bits/sec, *not*
1,048,576bits/sec.


	I think either a dual set of commands (if wanted), or
switching everything to line rates is needed.


	In other words, choose one (xbps or xbit) to stand for line
rates and document it, *or* change them all over.


	Just my humble opinion.

---
As folks might have suspected, not much survives except roaches, 
and they don't carry large enough packets fast enough...
        --About the Internet and nuclear war.