Robert,
On 10/03/2021 11:29, Robert Raszuk wrote:
Peter,
> But suddenly the DOWN event distribution is considered
> problematic. Not sure I follow.
In routing and IP reachability we use p2mp distribution and flooding as
it is required to provide any to any connectivity.
Such spray model no longer fits services where not every endpoint
participates in all services.
So my point is that just because you have transport ready we should not
continue to announce neither good nor bad news in spray fashion for
services.
Sure it works, but it is hardly a good design and sound architecture.
It happened to BGP as the convenience of already having TCP sessions
between nodes was so great that we loaded loads of stuff to go along
basic routing reachability.
And now it seems time came to do the same with IGPs :).
I think unless we stop and define a real pub-sub messaging protocol
(like FB does with open-R) we will continue this.
you are of course free to do that. Here we are at the LSR WG.
thanks,
Peter
And to me it is like building a tower from the cards ... the higher you
go the more likely your entire tower is to collapse.
Cheers,
R.
PS.
> with MPLS loopback address of all PEs is advertised everywhere.
Is this a feature or a day one design bug later fixed by RFC5283 ?
On Wed, Mar 10, 2021 at 9:10 AM Peter Psenak <ppse...@cisco.com
<mailto:ppse...@cisco.com>> wrote:
Robert,
On 09/03/2021 19:30, Robert Raszuk wrote:
> Hi Peter,
>
> > Example 1:
> >
> > If session to PE1 goes down, withdraw all RDs received
from such PE.
>
> still dependent on RDs and BGP specific.
>
>
> To me this does sound like a feature ... to you I think it was
rather
> pejorative.
not sure I understand your point with "pejorative"...
There are other ways to provide services outside of BGP - think GRE,
IPsec, etc. The solution should cover them all.
>
> We want app independent way of
> signaling the reachability loss. At the end that's what IGPs
do without
> a presence of summarization.
>
>
> Here you go. I suppose you just drafted the first use case for OSPF
> Transport Instance.
you said it, not me.
>
> I suppose you just run new ISIS or OSPF Instance and flood info
about PE
> down events to all other instance nodes (hopefully just PEs and
no Ps as
> such plane would be OTT one). Still you will be flooding this to
100s
> of PEs which may never need this information at all which I think
is the
> main issue here. Such bad news IMHO should be distributed on a
pub/sub
> basis only. First you subscribe then you get updates ... not get
> everything then keep junk till it get's removed or expires.
with MPLS loopback address of all PEs is advertised everywhere. So you
keep the state when the remote PE loopback is up and you get a state
withdrawal when the remote PE loopback goes down.
In Srv6, with summarization we can reduced the amount of UP state to
minimum. But suddenly the DOWN event distribution is considered
problematic. Not sure I follow.
thanks,
Peter
>
> Many thx,
> Robert
>
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