Re: UPC at the end system is not working.

[ud3@irz301.inf.tu-dresden.de (Uwe Dannowski)]

Alfonso Gonzales wrote:
> Unfortunately, it doesn't work. I keep receiving cells at maximum speed
> (around 20,000 cells per second) independently of the max_pcr used (100,
> 10 or 1 cell per second).
> Anybody have and explanation for this?
Yes, I have. And it's quite simple: The PCA-200E driver never inspects
vcc->qos (except for debug messages, of course) because the card doesn't
support anything of that QoS stuff.
The only feature is a rate control mechanism working on a per-PDU basis.
It's possible to set the ratio "idle cells per data cells" as a quotient of
two 16 bit numbers. Look at pca200e__send() where the tpd is filled:

  tpd->rc_stream_desc.data_cells = 0x0000;
  tpd->rc_stream_desc.empty_cells = 0x0000;

Having 0 in both disables the rate control -> should give maximum throughput.
One could calculate these two numbers from the vcc->qos member.

But using rate control could possibly lead to timing problems with other
conections when a 64K PDU is send with one data cell in 65535 idle cells.


Uwe

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Uwe Dannowski, student, Dresden University of Technology, Dept. of CS, OS group
email: Uwe_Dannowski@inf.tu-dresden.de  WWW: http://www.inf.tu-dresden.de/~ud3/
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