Re: [Rpm] Almost had a dialog going with juniper...

[Dave Taht <dave.taht@gmail.com>]

On Sun, Feb 19, 2023 at 3:44 PM rjmcmahon <rjmcmahon@rjmcmahon.com> wrote:
>
> It's a conflict in design goals. They're trying to sell to customers
> that don't want data loss in the data centers for things like RDMA
> messaging and claiming their equipment is universal to all use cases.
> It's really not.
>
> We're TCP end/end guys and packet loss can be a very good signal.

The test I did in that blog series was with RFC3168 ecn. No loss on the link.

> Bob
> > On Sun, Feb 19, 2023 at 3:34 PM rjmcmahon <rjmcmahon@rjmcmahon.com>
> > wrote:
> >>
> >> Their post isn't really about bloat. It's about the discrepancy in i/o
> >> bw of memory off-chip and on-chip.
> >
> > The original comment thread was about how the flow queuing aspect of
> > fq_codel derived algorithms, would leverage on-chip resources better,
> > and about how VOQs do misbehave today.
> >
> >
> >>
> >> My opinion is that the off-chip memory or hybrid approach is a design
> >> flaw for a serious router mfg.
> >
> > I concur. I think we need smarter buffering, not more buffering.
> > Admittedly while the overhead for
> > 10,000 fq_codel'd virtual queues (e.g. 1 million total queue states)
> > without tuning is presently 64M that needs to live in high speed
> > memory for that next indirect lookup... it is possible to trim that
> > down quite a lot.
> >
> >> The flaw is thinking the links' rates and
> >> the chip memory i/o rates aren't connected when obviously they are.
> >> Just
> >> go fast as possible and let some other device buffer, e.g. the end
> >> host
> >> or the server in the cloud.
> >
> > Juniper will hold onto their big buffers are
> > profitable^H^H^H^H^H^H^H^Hneeded strategy until the bitter end.
> >
> >>
> >> Bob
> >> > https://blog.cerowrt.org/post/juniper/
> >> >
> >> > But they deleted the comment thread. It is interesting, I suppose, to
> >> > see how they frame the buffering problems to themselves in their post:
> >> > https://www.linkedin.com/pulse/sizing-router-buffers-small-new-big-sharada-yeluri/



-- 
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Dave Täht CEO, TekLibre, LLC