On 10/20/21 20:37, Lady Benjamin Cannon of Glencoe, ASCE wrote:
-48VDC power is still the best.
I really envy folk that love DC for networking gear :-). Work in 2007 was an all-DC network. I rebuilt it into AC, considering the ISP also owned the data centre (most of whose customers bought AC). The space we freed up and the ease of deployment was night & day. Currently, we obviously need DC for the terrestrial Transport and wet plants (because that's just how classic telco rolls), but I also switched all IP/MPLS gear to AC soon as I arrived. Heck, even the Arbor (now Netscout) gear, as well as the HP server rack, was loaded with DC power supplies. Those things just had to go. There is an avenue of pleasure in not having to spend inordinate amounts of time adding major electrical planning to deploying/decommissioning a router, switch or server. But yeah, I know the AC vs. DC discussion can become a rat hole. I'm aware of data centre operators now providing DC as an option for their expansion projects, when they previously had it as the norm, FWIW. Mark.
Outside the datacenter is where DC power really shines in my opinion. Inside the DC, everything is AC now and probably for the best. We never came up with a modular standard for -48VDC. Perhaps that could have changed things. But it sure is nice having 72hrs of battery run time in the field/edge - although those are becoming mini data centers themselves and are in turn also slowly going AC. Ms. Lady Benjamin PD Cannon of Glencoe, ASCE 6x7 Networks & 6x7 Telecom, LLC CEO lb@6by7.net "The only fully end-to-end encrypted global telecommunications company in the world.” FCC License KJ6FJJ Sent from my iPhone via RFC1149.
On Oct 20, 2021, at 10:19 PM, Mark Tinka <mark@tinka.africa> wrote:
On 10/20/21 20:37, Lady Benjamin Cannon of Glencoe, ASCE wrote:
-48VDC power is still the best.
I really envy folk that love DC for networking gear :-).
Work in 2007 was an all-DC network. I rebuilt it into AC, considering the ISP also owned the data centre (most of whose customers bought AC). The space we freed up and the ease of deployment was night & day.
Currently, we obviously need DC for the terrestrial Transport and wet plants (because that's just how classic telco rolls), but I also switched all IP/MPLS gear to AC soon as I arrived. Heck, even the Arbor (now Netscout) gear, as well as the HP server rack, was loaded with DC power supplies. Those things just had to go.
There is an avenue of pleasure in not having to spend inordinate amounts of time adding major electrical planning to deploying/decommissioning a router, switch or server.
But yeah, I know the AC vs. DC discussion can become a rat hole.
I'm aware of data centre operators now providing DC as an option for their expansion projects, when they previously had it as the norm, FWIW.
Mark.
On Oct 21, 2021, at 13:50 , Lady Benjamin Cannon of Glencoe, ASCE <lb@6by7.net> wrote:
Outside the datacenter is where DC power really shines in my opinion. Inside the DC, everything is AC now and probably for the best.
We never came up with a modular standard for -48VDC. Perhaps that could have changed things.
I’m actually surprised the industry never standardized on the connectors used in Forklifts. They’re basically a large-current variant of Anderson Power Pole style connectors, but they come in a fixed two-conductor format. They are genderless connectors with excellent durability and very easy assembly. This is an example of the 175A rated version: https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwix29Cn4dzzAhWAPq0GHXbQBIsYABAwGgJwdg&ae=2&ohost=www.google.com&cid=CAESQeD2msApqo8j1XMaWbSlUZSb5GKwd-_HS9fjxEHuC1OZtIF_P1TcvIJf6iU1eWg7zXydeBdm7vKY48oTxpBuYKqk&sig=AOD64_0UQZ9Dc5Zv-hSYz-76-eM0uMPfKQ&q&adurl&ved=2ahUKEwjprsSn4dzzAhWCIDQIHYCNAzcQ0Qx6BAgCEAE&dct=1 They come in sizes from 120A to 350A. Owen
On 10/21/21 22:50, Lady Benjamin Cannon of Glencoe, ASCE wrote:
Outside the datacenter is where DC power really shines in my opinion. Inside the DC, everything is AC now and probably for the best.
We never came up with a modular standard for -48VDC. Perhaps that could have changed things.
But it sure is nice having 72hrs of battery run time in the field/edge - although those are becoming mini data centers themselves and are in turn also slowly going AC.
I suppose it depends what business you are in. If you are a mobile operator and have towers in all sorts of places where utility mains may be unavailable or spotty, I guess having to convert DC to AC makes little sense if that's your primary source of power (especially since solar PV, wind turbines and batteries all output DC power anyway). We run a fair bit of Metro-E network in the countries we operate, and most of that is in standard commercial buildings that are not data centres. Even there, we run AC, with a UPS, and rely on the building generator for an alternate AC source in case of a mains outage. But yes, for our terrestrial Transport network, that's all DC anyway, regardless of the power source. Mark.
One of the 4 or 5 datacenters in downtown Tampa had a telco or offshoot in their spaces, when I took All The Tours about 9 years ago. They have 8x750MCM hauling -48VDC from their power plant to the cage in question. On each side. It was, in fact, pretty impressive to look at. But I was a little worried about the loading on the building frame. :-) And while I think there might be advantages in running power supplies in gear at -48, I'd want to rectify it in the cage, preferably from 480/3ph. Cheers, -- jra ----- Original Message -----
From: "Lady Benjamin Cannon of Glencoe, ASCE" <lb@6by7.net> To: "Mark Tinka" <mark@tinka.africa> Cc: "NANOG Operators' Group" <nanog@nanog.org> Sent: Thursday, October 21, 2021 4:50:10 PM Subject: Re: Network visibility
Outside the datacenter is where DC power really shines in my opinion. Inside the DC, everything is AC now and probably for the best.
We never came up with a modular standard for -48VDC. Perhaps that could have changed things.
But it sure is nice having 72hrs of battery run time in the field/edge - although those are becoming mini data centers themselves and are in turn also slowly going AC.
Ms. Lady Benjamin PD Cannon of Glencoe, ASCE 6x7 Networks & 6x7 Telecom, LLC CEO lb@6by7.net "The only fully end-to-end encrypted global telecommunications company in the world.”
FCC License KJ6FJJ
Sent from my iPhone via RFC1149.
On Oct 20, 2021, at 10:19 PM, Mark Tinka <mark@tinka.africa> wrote:
On 10/20/21 20:37, Lady Benjamin Cannon of Glencoe, ASCE wrote:
-48VDC power is still the best.
I really envy folk that love DC for networking gear :-).
Work in 2007 was an all-DC network. I rebuilt it into AC, considering the ISP also owned the data centre (most of whose customers bought AC). The space we freed up and the ease of deployment was night & day.
Currently, we obviously need DC for the terrestrial Transport and wet plants (because that's just how classic telco rolls), but I also switched all IP/MPLS gear to AC soon as I arrived. Heck, even the Arbor (now Netscout) gear, as well as the HP server rack, was loaded with DC power supplies. Those things just had to go.
There is an avenue of pleasure in not having to spend inordinate amounts of time adding major electrical planning to deploying/decommissioning a router, switch or server.
But yeah, I know the AC vs. DC discussion can become a rat hole.
I'm aware of data centre operators now providing DC as an option for their expansion projects, when they previously had it as the norm, FWIW.
Mark.
-- Jay R. Ashworth Baylink jra@baylink.com Designer The Things I Think RFC 2100 Ashworth & Associates http://www.bcp38.info 2000 Land Rover DII St Petersburg FL USA BCP38: Ask For It By Name! +1 727 647 1274
On 10/22/21 1:13 AM, Jay R. Ashworth wrote:
It was, in fact, pretty impressive to look at. But I was a little worried about the loading on the building frame. :-)
And while I think there might be advantages in running power supplies in gear at -48, I'd want to rectify it in the cage, preferably from 480/3ph.
High voltage DC (400v) has all the advantages of DC with none of the lossy drawbacks of -48v. What's nice is most every AC PSU now will run off it with minor modifications, so it's trivial for vendors to support. Nokia and Juniper even do it in the same AD/HVDC supply. I like DC, it's much simpler, but it's a lower volume product. One advantage to AC is I can call any electrocution and they can run a cable in a pinch for me. DC, even though it's the same physics, is harder to find experienced tech to work with. -- Bryan Fields 727-409-1194 - Voice http://bryanfields.net
participants (5)
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Bryan Fields -
Jay R. Ashworth -
Lady Benjamin Cannon of Glencoe, ASCE -
Mark Tinka -
Owen DeLong