<div dir="ltr"><div class="gmail_default" style="font-size:small"><br></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Thu, Jul 31, 2014 at 4:13 PM, Wes Felter <span dir="ltr"><<a href="mailto:wmf@felter.org" target="_blank">wmf@felter.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="">On 7/30/14, 5:49 PM, Dave Taht wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
I have been following the level3 vs verizon debate with some interest,<br>
trying to sort out fact from fiction. It does appear that once they<br>
saturate a core interconnect they end up with nearly 100ms of latency in<br>
it. Is RED not available on 10GigE interconnects or any other mediation<br>
means to increase packet loss in exchange for getting better latency?<br>
</blockquote>
<br></div>
Wasn't CoDel created because nobody understands how to configure RED?<br></blockquote><div><br></div><div class="gmail_default" style="font-size:small">More or less.... Dave Oran noted at one IETF meeting that RED tuning (at least on Cisco gear) might not even be stable between different versions of their operating system.</div>
<div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">CoDel's goal was to be a "do no harm" aqm safe enough to always have turned on (according to Kathie and Van).</div>
<div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">But RED mistuned can hurt you (or so I gather).... And testing your tuning under load is not something you want to do, even if you can arrange it.</div>
<div class="gmail_default" style="font-size:small"><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
If you've built a network under the assumption that congestion won't happen, why enable RED?<br></blockquote><div><br></div><div class="gmail_default" style="font-size:small">Backhoe events, tsunamis, and peering disputes show that congestion does happen. And it takes time to lay more fiber, particularly in backbone networks. Crystal ball gazing goes only so far on avoiding congestion in the core. But see above...</div>
<div class="gmail_default" style="font-size:small"></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
If you're in an adversarial public pissing match, is your incentive to make the situation look better or worse?</blockquote><div><br></div><div class="gmail_default" style="font-size:small">It's commonplace, and given RED's difficulty, hardly surprising to me that many peering points run without it.</div>
<div class="gmail_default" style="font-size:small"><br></div><div class="gmail_default" style="font-size:small">Also note that the *actual* bottleneck may not even be in a device where you have (W)RED present; switches are widespread...</div>
<div class="gmail_default" style="font-size:small"> - Jim</div><div class="gmail_default" style="font-size:small"></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<span class="HOEnZb"><font color="#888888"><br>
<br>
-- <br>
Wes Felter<br>
<br>
<br>
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