<html><head></head><body>It really depends on what you're interconnecting. <br><br>Some NICs don't support SM optics, so even if you would like to run SM everywhere, it's not necessarily possible depending on the equipment.<br>For example, I had issues with some SolarFlare cards which happily take 10G-SR MM but won't take 10G-LR SM.<br><br>Filip<br><br><div class="gmail_quote">On 26 February 2020 5:30:56 pm GMT+01:00, Warren Kumari <warren@kumari.net> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail">On Wed, Feb 26, 2020 at 11:20 AM Coy Hile <coy.hile@coyhile.com> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"><br> On 2020-02-26 11:14, Randy Bush wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #ad7fa8; padding-left: 1ex;"><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #8ae234; padding-left: 1ex;">We use plenty of multi-mode, but only in the data centre, between our<br>own kit, for racks within the same cage.<br></blockquote><br> so you have to stock both single and multi? hmmm<br><br> randy<br></blockquote><br> I'd expect that from the ToR -> Servers would be MMF, but that other<br> infrastructure cabling would be SMF.<br> Even using aftermarket optics, putting single-mode transceivers in every<br> server and access port would quickly become cost-prohibitive, would it<br> not?<br></blockquote><br>Cisco GLC-SX-MM Compatible 1000BASE-SX SFP 850nm 550m DOM Transceiver<br>Module - $6.00 - <a href="https://www.fs.com/products/11774.html">https://www.fs.com/products/11774.html</a><br>Cisco SFP-GE-L Compatible 1000BASE-LX/LH SFP 1310nm 10km DOM<br>Transceiver Module - $7.00 - <a href="https://www.fs.com/products/12622.html">https://www.fs.com/products/12622.html</a><br><br>Yup, it is $1.00 more for SM, and you need 2 per link, but unless you<br>are doing *lots* that's likely not cost-prohibitive. The delta on 10G<br>is a bit more ($21 vs $18), but still not crazy-pants territory...<br><br>Of course, sometimes you don't have the option of SM - you are<br>connecting some someone else than they only do MM, or you are<br>connecting to a piece of kit which doesn't have replaceable optics, or<br>you have legacy cabling which is MM, or... but, the cost of the optics<br>these days is not really the limiting factor.<br><br><blockquote class="gmail_quote" style="margin: 0pt 0pt 1ex 0.8ex; border-left: 1px solid #729fcf; padding-left: 1ex;"><br> --<br> Coy Hile<br> coy.hile@coyhile.com<br></blockquote><br><br></pre></blockquote></div><br>-- <br>Sent from my mobile device. Please excuse my brevity.</body></html>