Mirja -

In regards to Section 6.3...


> 
> Sec 6.3
> This section is entirely not clear to me. There is no algorithm described and 
> I
> would not know how to implement this.

[LES:] This is intentional.
As this approach is NOT dependent on any signaling from the receiver, the 
transmitter is free to implement in whatever manner it finds effective - there 
are no interoperability issues.
As we state:

"Such an algorithm is a local matter and there is no requirement or intent to 
standardize an algorithm."

> Also because you interchangeably
> use the
> terms congestion control and flow control. 

[LES:]  Good point.
I believe we should use the term "congestion control" throughout this section.
Will work with Bruno to make that change.

> Further you say that no input
> signal
> from the receiver is needed, however, if you want to send with the rate of
> acknowledgement received that is an input from the receiver. 

[LES:] The use of the neighbor partialSNPInterval sub-TLV (Section 4.5) is 
optional.
It may be useful, but as our intention is to have the algorithm work with 
legacy neighbors who do not support the additional advertisements defined in 
this document, it is necessary that the algorithm work well even in the absence 
of that signaling.
If by "rate of acknowledgement ...is an input from the receiver" you think we 
are contradicting ourselves, I will gently pushback.
We have not changed the operation of the Update Process in any way. So the acks 
we receive and the rate at which they were received is information which is 
available today from current operation of the Update Process. To date it just 
hasn’t been used to influence transmission rate of other LSPs - it has only 
been used to cancel retransmissions on the LSPs already sent.

[ >However, the
> window based TCP-like algorithms does actually implicitly exactly that: it 
> only
> send new data if an acknowledgement is received. It further also takes the
> number of PDUs that are acknowledged into account because that can be
> configured. If you don’t do that, you sending rate will get lower and lower.
> 
[LES:] Paragraphs 4, 5, 6 discuss both slowing down the transmission rate and 
speeding up the transmission rate. The algorithm needs to do both - and does so 
based on the actual performance i.e., how quickly ACKs have been received.
Paragraph 6 highlights that we cannot assume that performance is static. If you 
think that once we slow down we will never speed up then please reread 
Paragraph 5.

At the risk of repeating myself, I emphasize that lack of dependence on 
signaling by the receiver is a key element of this approach which enables it to 
work with both legacy and upgraded nodes.

   Les
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