Re: WG chair on buffer exhaustion

On Monday, July 21, 2003, at 02:33 PM, David Robinson wrote:

> I would venture that it is not worth a discussion of the
> advantages and disadvantages of such trickery as failing
> to ACK. Simply state that lower layers MAY delay delivery
> of an untagged message to DDP when no buffers are available,
> details are left to the implementation.

To the degree that it is an implementation tradeoff, that is true.
But I believe it is relevant to simply state along the lines that
David has suggested that false drops have an impact on the
entire network, and that this solution should be kept to an
absolute minimum.

It is also important that we recognize that the ULP MUST have
some form of flow control, and that *if* that information has
been shared with the DDP Layer via the local interface that
the DDP Layer not only MAY, but MUST terminate the stream
when it receives an untagged segment with an out-of-range
MSN. Pat Thaler's comments last week provide some solid
reasons as to why it would be a bad idea to *mandate* that
this information MUST be shared.

I still think it's worthy of a Must Implement, but there were
valid application models raised where the local ULP
would not want to be bothered with communicating
the limit to the DDP layer.


Caitlin Bestler - [email protected] - http://asomi.com/