Re: [Lsr] Fwd: Open issues with Dynamic Flooding

["Les Ginsberg (ginsberg)" <[e-mail]>]

Huaimo -

I am aware of the other thread and the discussion you are having with Tony.
My reading of it is that you have not yet defined a deterministic solution to this problem - you have only defined the goal. If you do define a deterministic solution, that would be most welcome and we can then incorporate it in the Dynamic Flooding draft.

Please continue the thread w Tony.

Thanx.

   Les


> -----Original Message-----
> From: Huaimo Chen <[e-mail]>
> Sent: Tuesday, April 09, 2019 8:47 AM
> To: Les Ginsberg (ginsberg) <[e-mail]>; [e-mail];
> [e-mail]
> Subject: RE: [Lsr] Fwd: Open issues with Dynamic Flooding
> 
> Hi Les,
> 
>     For "add temporary flooding in a rate limited manner", can you give some
> details about how does the rate limit manner work for fixing a FT split? how
> does each node get the rate limit? Will every node add temporary flooding
> on a given number of links independently? If so, there are lots of links to be
> added into the FT temporarily for fixing the FT split. This may cause some
> issues.
>     In another thread "[Lsr] Min Links for Multiple Failures on Flooding
> Topology", there is a solution for fixing the FT split using almost minimum
> number of links.
> 
> Best Regards,
> Huaimo
> -----Original Message-----
> From: Lsr [mailto:[e-mail]] On Behalf Of Les Ginsberg (ginsberg)
> Sent: Tuesday, April 9, 2019 11:09 AM
> To: [e-mail]; [e-mail]
> Subject: Re: [Lsr] Fwd: Open issues with Dynamic Flooding
> 
> Tony -
> 
> Here is my take.
> 
> Regarding Issue #2 below, we had a healthy thread on this since Prague and I
> believe have consensus that we WILL support LANs in the encoding of the
> flooding topology (centralized mode). Authors need to agree on changes to
> the draft which we will take offline and then publish an update.
> 
> Regarding Issue #1 below, we did have a thread on this BEFORE Prague and
> seemed to reach consensus on:
> 
> <snip>
> Let me propose that we add something to sections 6.7.5, 6.7.9, and 6.7.11
> like:
> 
> Addition of temporary flooding should be done with caution, as the addition
> of excessive connectivity to the flooding topology may trigger unwanted
> behavior. Routers SHOULD add temporary flooding in a rate limited manner,
> if not configured otherwise.
> 
> <end snip>
> 
> (See attached email)
> 
> Again, authors need to address this in the next draft revision but I believe we
> have agreement in principle.
> 
> So I think we can consider these matters resolved - pending WG feedback on
> the updated draft whenever it becomes available.
> 
>    Les
> 
> 
> > -----Original Message-----
> > From: Lsr <[e-mail]> On Behalf Of [e-mail]
> > Sent: Monday, April 08, 2019 7:27 AM
> > To: [e-mail]
> > Subject: [Lsr] Fwd: Open issues with Dynamic Flooding
> >
> >
> > Hi all,
> >
> > It’s been another week and we’ve had a few more very interesting
> > conversations, but we seem to have not moved very far.
> >
> > Have we converged?
> >
> > Tony
> >
> >
> >
> > > Hi all,
> > >
> > > I hope that everyone had a safe and uneventful trip home from Prague
> > > and
> > that no one else had the seat right in front of the screaming baby.
> > ;-)
> > >
> > > I would like to re-open the discussion on the mailing list. Based on
> > > the off-
> > line discussions that I had with folks, I believe that we’re leaning
> > towards including the LANs in the signaling and rate limiting link addition
> during repair.
> > >
> > > Dissent? Discussion?
> > >
> > > Tony
> > >
> > >
> > >> On Mar 4, 2019, at 9:54 AM, [e-mail] wrote:
> > >>
> > >>
> > >> Hello,
> > >>
> > >> There are still two issues that need to be discussed and I was
> > >> hoping that
> > we could make progress on the mailing list before Prague.
> > >>
> > >> 1) Temporary additions to the flooding topology
> > >>
> > >>   There are several cases where we would like to make temporary
> > additions to the flooding topology: repairing a partition of the
> > flooding topology or adding a node to the base topology for the first time.
> We can:
> > >>
> > >>   (a) Temporarily add all of the links that would appear to remedy
> > >> the
> > partition. This has the advantage that it is very likely to heal the
> > partition and will do so in the minimal amount of convergence time.
> > >>
> > >>   (b) For each node adjacent to the partition, add no more than a
> > >> single
> > link across the partition.  If that does not repair the partition in a
> > while (LSP propagation time + SPF time), then add another link.
> > >>        Iterate as necessary. This has the advantage that it
> > >> minimizes the risk
> > of creating a cascade failure.
> > >>
> > >> 2) Inclusion of pseduonodes in the System IDs TLV
> > >>
> > >>   In the general case, a topology can include LANs. If a LAN is in
> > >> parallel
> > with a P2P link, the Area Leader cannot currently distinguish between
> > the two links. This can be of importance if there are other
> > >>   systems also on the LAN that should be using their LAN interface
> > >> for
> > flooding.
> > >>
> > >>   We propose to change the System IDs TLV to include a pseudo-node
> > >> ID
> > as well as the system ID.  It would also make sense to rename the TLV
> > to be the “IS-IS Area Node IDs TLV”.
> > >>
> > >>   Behaviorally, we should add a requirement that if the Area Leader
> > includes a pseudonode in the flooding topology, then all systems with
> > an adjacency on that LAN should use the LAN as part of the
> > >>   flooding topology, whether or not they are explicitly listed as
> > >> adjacent to
> > the LAN in the Flooding Path TLV.
> > >>
> > >> Thoughts? Comments? Flames?
> > >>
> > >> Regards,
> > >> Tony
> > >>
> > >
> >
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