[Rstplib-users] RE: 802.1w: 3 questions about flushing

[<alb...@ya...>]

Alex, thank you, but I am not sure, that undesrtand
you :(
How may txHoldTimer "prevent" tcWhile decrementing ?
What do you mean under "driver below STP engine" ?
Why in .1s there is no clarifications about flushing ?
Albina


 --- Alex Ruzin <al...@nb...> wrote: > 
> On Monday, January 07, 2002 Albina Krigma-Lee wrote:
> 
> Albina > Question 1. tcWhile decrementing.
> Albina > When Topology Change is DETECTED, the timer
> tcWhile
> Albina > accepts a value 4 (twice HelloTime). Then,
> the PTM binds
> Albina > "topology change flag" in BPDU. While in
> pure RSTP
> Albina > LAN there are no "topology change
> acknowledgements",
> Albina > this timer is decremented until 0 "by
> natural".
> Albina > So, there are 2 outgoing BPDU with
> "topology change
> Albina > flag": the Albina > first – when tcWhile=4;
> the second
> Albina > – when tcWhile=2.
> Albina > If the considerations above are right, it
> seems, that Alex is
> Albina > optimist: it will be "triple" flushing, not
> double!
> 
Alex> I would like to believe, that txHoldTimer will
Alex> prevent it
> 
> Albina > Question 2. Do we have to make FDB flushing
> for a
> Albina > Port when this Port becomes "Disabled" (or,
> let us
> Albina > say, Albina > macOperational=FALSE).
> Albina >
> Albina > Let us consider a Bridge and 2 stations U1
> and U2.
> Albina > Station U1 is connected to Port P1; station
> U2 - to
> Albina > Port P2.
> Albina > Station U2 sends ping responses to U2 and
> receives
> Albina > ping replies from it.
> Albina >
> Albina > Now we disconnect U2 from P2 and connect it
> to the
> Albina > Port P3.
> Albina >
> Albina > While station U2 is silent (it acts as
> "passive" echo
> Albina > server and doesn't send anything without
> request) and
> Albina > Filtering Database entry that holds U2 on
> Port P2 continues to
> Albina > be valid, the Bridge forwards  responds to
> "disabled" Port P2.
> Albina > So, the poor U1 will not see U2 until ARP
> entry aging Albina > :(
> 
> I think, Bridge does have to make flushing on Link
> Down, but it seems to be
> a business of some driver below STP engine. The same
> problem will be
> without STP, will not it ?
> 
> Albina > Question 3. In 1s: Do we have to make
> flushing per all
> Albina > tags  in an MSTi ?
> 
Alex> IMHO, yes.
> 
> Albina > And what about CSTi ?
Alex> I don't sure, IMHO in CSTi the function flush()
must
Alex> flush *all* entries of
Alex> the Port,
Alex> I mean for all tags. Anyway, let's wait for
Alex> explanations from WG :)
> 
> Albina > Yours truly, Albina
> 
Alex> Best regards, Alex
Alex> ---------------------
Alex> Open Source RSTP 
Alex> https://sourceforge.net/projects/rstplib/
Alex> Optical Access Ltd. http://www.opticalaccess.com
>  

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