Re: [Lsr] 答复: 答复: Option B from "Migration between normal flooding and flooding reduction"

Aijun -

Please look at https://tools.ietf.org/html/draft-ietf-lsr-dynamic-flooding-02#section-6.4 which defines how to disable dynamic flooding w/o resigning as Area Leader.

Note that having deployed dynamic flooding in a network which functions poorly in its absence, disabling dynamic flooding has risks.
Nonetheless, I agree we need a way to disable dynamic flooding and it is helpful to be able to do so w/o altering what all possible area leader candidates are advertising - and we have that.

   Les

> -----Original Message-----
> From: Lsr <lsr-bounces@ietf.org> On Behalf Of Aijun Wang
> Sent: Tuesday, May 28, 2019 6:44 PM
> To: Peter Psenak (ppsenak) <ppsenak@cisco.com>; 'Tony Li'
> <tony1athome@gmail.com>; 'Robert Raszuk' <robert@raszuk.net>
> Cc: lsr@ietf.org
> Subject: [Lsr] 答复: 答复: Option B from "Migration between normal flooding
> and flooding reduction"
> 
> Hi, Peter:
> 
> Under the current mechanism, only all the candidate area leaders stop
> advertise this sub-TLV, then the network will be back to normal flooding?
> Is it more efficient that only one area leader indicates(according to the
> command from NMS) explicitly then the network will be back to normal
> flooding?
> 
> For the number of candidate area leaders, I support we should have more
> than one for consideration of redundancy.
> 
> -----邮件原件-----
> 发件人: Peter Psenak [mailto:ppsenak@cisco.com]
> 发送时间: 2019年5月28日 15:34
> 收件人: Aijun Wang; 'Tony Li'; 'Robert Raszuk'
> 抄送: lsr@ietf.org
> 主题: Re: [Lsr] 答复: Option B from "Migration between normal flooding and
> flooding reduction"
> 
> Aijun,
> 
> On 28/05/2019 08:15, Aijun Wang wrote:
> > Hi, Tony:
> >
> > How the receiver judge the leader has stopped advertising the Area Leader
> sub-TLV? Do you need some timers?
> 
> no timer needed, all event driven. Area Leader sub-TLV is removed from the
> LSP.
> 
> thanks,
> Peter
> 
> >>From the current discussion, I think the explicit instruction that proposed
> by Huaimo is more acceptable.
> >
> >
> > Best Regards.
> >
> > Aijun Wang
> > Network R&D and Operation Support Department China Telecom
> Corporation
> > Limited Beijing Research Institute,Beijing, China.
> >
> > -----邮件原件-----
> > 发件人: Tony Li [mailto:tony1athome@gmail.com]
> > 发送时间: 2019年5月27日 12:20
> > 收件人: Robert Raszuk
> > 抄送: lsr@ietf.org
> > 主题: Re: [Lsr] Option B from "Migration between normal flooding and
> flooding reduction"
> >
> >
> > Hi Robert,
> >
> >> The current draft is pretty robust in terms of area leader election. It also
> says that  "Any node that is capable MAY advertise its eligibility to become
> Area Leader”
> >
> >
> > Correct.  This can be all systems. It can be one. For redundancy, a few
> would be sensible.
> >
> >
> >> With that can you confirm the procedure to "resign" as area leader ?
> >
> >
> > Stop advertising the Area Leader sub-TLV.  It’s that simple.
> >
> >
> >> Especially that under those circumstances just having active area leader to
> resign clearly is not enough to change given flooding scheme.
> >
> >
> > If there are multiple potential area leaders, then all of them would have to
> resign.
> >
> >
> >> In some deployments all eligible nodes may advertise such capability
> which in turn the "resign" procedure would require NMS action to disable
> such capability by configuration and re-flooding it. Not that I am advocating it
> nor see need for complex migration procedures, but just would like to better
> understand the "resign" part.
> >
> >
> > Correct, this is rightfully an NMS operation.
> >
> > Tony
> >
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> 
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