packet reordering at exchange points

Tue Apr 9 18:16:24 UTC 2002

> Hmmmm.  You're right.  I lost sight of the original thread...
> GigE inter-switch trunking at PAIX.  In that case, congestion
> _should_ be low, and there shouldn't be much queue depth.

indeed, this is the case.  we keep a lot of headroom on those trunks.

> But this _does_ bank on current "real world" behavior.  If
> endpoints ever approach GigE speeds (of course requiring "low
> enough" latency and "big enough" windows)...
> 
> Then again, last mile is so slow that we're probably a ways away
> from that happening.

my expectation is that when the last mile goes to 622Mb/s or 1000Mb/s,
exchange points will all be operating at 10Gb/s, and interswitch trunks
at exchange points will be multiples of 10Gb/s.

> Of course, I'd hope that individual heavy pairs would establish
> private interconnects instead of using public switch fabric, but
> I know that's not always { an option | done | ... }.

individual heavy pairs do this, but as a long term response to growth,
not as a short term response to congestion.  in the short term, the
exchange point switch can't present congestion.  it's just not on the
table at all.