Economic rationale for the use of PoE (Power over Ethernet)
Searching through habraprostor, I realized that almost nobody wrote about the use of PoE technology, so I decided to share my experience in plowing this field.
WIKI (recall what PoE is)
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Preamble
It all began shortly before the crisis, and in October 2008 reached a climax. A certain company acquired in defaultCity a certain building into which, after renovation, it planned to enter and work. Before the purchase, there was an entertainment facility in the building, and, in general, the networks, telephones, and video surveillance in the building were not very good. But rather not at all good. And if it is absolutely fair - then absolutely everything was bad.
The author, being at that moment “early. IT department ", and, by and large," responsible for everything ", what are the wiring and current - was assigned to the tasks - to implement in the building 225 jobs for staff (office - computer, telephone), server, and the system CCTV (there was some awful analog G in the building, it was as fascinating to look at it as it was to spy on the girls in a public bath through the keyhole - everything was in pairs, nothing could be seen), and some more specific systems.
In general, I was puzzled, and sat down to write Technical Specification (TK) for all this, combining it into an Automated System (AC) - a shop to write everything according to GOST 34.
For a start, I went around all the managers of the divisions, collected their Wishlist, ran it into my thought, counted it, brought it to the signature. The leadership grunted, but it was still May 2008, the money was still there, and, reluctantly, signed the papers.
Quietly and peacefully everyone lived until September 2008, when everyone “started” - the building in which the office rented the premises raised the rent + required a deposit six months in advance. The management made a decision - 1) to urgently repair its building and move as fast as possible into it, 2) to save on everything that can be saved during the repair process.
And since the installation of HP switches with PoE was planned in the new building, and the amounts for them were serious, we had to fight for them as well.
Ambula
In GOST 34 there is a very interesting part - the feasibility study of the project - in terms of economy in the future, I decided to build a rationale for the use of PoE.
So, given - tel.stantsiya Alcatel OMNI PCX Ent (IP) - this bastard was purchased before the Kryzys, 220 phones Alcatel 4018 + 5 tel. Alcatel with secretarial functions, I do not remember the model, in general, and it does not matter - 225 phones. Alcatel 4018 has 2 ports - through the phone you can connect the computer to the SCS for 100 Mbps.
To connect all this stuff - 5 switches X 48 ports - there is still 15 cameras (Axis, ACTi) in place. RoE switches are expensive (by the way, in the HP line, they are indicated by the addition of the PWR name). We start to count on what we can save.
225 Alcatel phones come without power supplies - this is the policy. Separately, the power supply unit (PSU) GPSU15B-8 costs at least 800 rubles, all units - 180,000 rubles. Already not bad, since with PoE we do not need blocks.
We pick the blocks, and at the same time switches.
1) The GPSU15B-8 block is an ordinary transformer block, 15W. The efficiency of such a unit is ~ 60%
But to transfer power from the switch to the phone, a pulse power supply unit is used, its efficiency is ~ 98%. The switches themselves are powered by UPS, there are also pulsed power supplies, the overall efficiency of the switch + UPS pair is 96%.
2) A telephone with a power supply is always connected to the network, acc. constantly consuming their 15 W - 24 hours a day, 365 days a year. Switches with PoE function allow you to manage power. This means that a phone connected using PoE will consume 15 W only at the time of direct use of the device (receiving / transmitting a call, working with a menu), the rest of the time the phone will be in standby mode and consume a few tenths of a watt.
We take out the calculator, we start counting - 15W * 24hours * 365days / 0.6 Efficiency = 219 kW * hour per year - according to the scheme “telephone + BP” one workplace eats 219 kilowatt-hours per year.
And all 225 places - 49.3 megawatt-hours per year.
When switched on according to the “PoE phone” scheme, I assumed conditionally that the switch consumes energy, but not phones - the switch consumes about 80 W (the working computer without frills consumes about 60 W, measured it itself), and then the switch controls the distribution of energy to the phones - total 80W * 24hours * 365 days / 0.96 (KPD) = 730 kW * h / year. 5 switches, sootv. - 3.65 MW * h / year
The difference in power consumption is 45.65 MW * h. At the then cost of lipidism, savings of ~ 170,000 rubles a year came out.
Total - 350 000 r - for the first year this model pays off.
This is in addition to the fact that it is almost impossible to connect additional electrical power to the building in defaultCity even for a bribe physically carried by one person, and the problem of power shortage is quite acute and frequent.
isp. materials -
WIKI (recall what PoE is)
Power over Ethernet, or PoE, is a technology that allows electric power to be transmitted to a remote device along with data through a standard twisted pair over an Ethernet network. This technology is intended for IP-telephony, access points of wireless networks, Web-cameras, network hubs and other devices to which it is undesirable or impossible to conduct a separate electrical cable.
')
Preamble
It all began shortly before the crisis, and in October 2008 reached a climax. A certain company acquired in defaultCity a certain building into which, after renovation, it planned to enter and work. Before the purchase, there was an entertainment facility in the building, and, in general, the networks, telephones, and video surveillance in the building were not very good. But rather not at all good. And if it is absolutely fair - then absolutely everything was bad.
The author, being at that moment “early. IT department ", and, by and large," responsible for everything ", what are the wiring and current - was assigned to the tasks - to implement in the building 225 jobs for staff (office - computer, telephone), server, and the system CCTV (there was some awful analog G in the building, it was as fascinating to look at it as it was to spy on the girls in a public bath through the keyhole - everything was in pairs, nothing could be seen), and some more specific systems.
In general, I was puzzled, and sat down to write Technical Specification (TK) for all this, combining it into an Automated System (AC) - a shop to write everything according to GOST 34.
For a start, I went around all the managers of the divisions, collected their Wishlist, ran it into my thought, counted it, brought it to the signature. The leadership grunted, but it was still May 2008, the money was still there, and, reluctantly, signed the papers.
Quietly and peacefully everyone lived until September 2008, when everyone “started” - the building in which the office rented the premises raised the rent + required a deposit six months in advance. The management made a decision - 1) to urgently repair its building and move as fast as possible into it, 2) to save on everything that can be saved during the repair process.
And since the installation of HP switches with PoE was planned in the new building, and the amounts for them were serious, we had to fight for them as well.
Ambula
In GOST 34 there is a very interesting part - the feasibility study of the project - in terms of economy in the future, I decided to build a rationale for the use of PoE.
So, given - tel.stantsiya Alcatel OMNI PCX Ent (IP) - this bastard was purchased before the Kryzys, 220 phones Alcatel 4018 + 5 tel. Alcatel with secretarial functions, I do not remember the model, in general, and it does not matter - 225 phones. Alcatel 4018 has 2 ports - through the phone you can connect the computer to the SCS for 100 Mbps.
To connect all this stuff - 5 switches X 48 ports - there is still 15 cameras (Axis, ACTi) in place. RoE switches are expensive (by the way, in the HP line, they are indicated by the addition of the PWR name). We start to count on what we can save.
225 Alcatel phones come without power supplies - this is the policy. Separately, the power supply unit (PSU) GPSU15B-8 costs at least 800 rubles, all units - 180,000 rubles. Already not bad, since with PoE we do not need blocks.
We pick the blocks, and at the same time switches.
1) The GPSU15B-8 block is an ordinary transformer block, 15W. The efficiency of such a unit is ~ 60%
But to transfer power from the switch to the phone, a pulse power supply unit is used, its efficiency is ~ 98%. The switches themselves are powered by UPS, there are also pulsed power supplies, the overall efficiency of the switch + UPS pair is 96%.
2) A telephone with a power supply is always connected to the network, acc. constantly consuming their 15 W - 24 hours a day, 365 days a year. Switches with PoE function allow you to manage power. This means that a phone connected using PoE will consume 15 W only at the time of direct use of the device (receiving / transmitting a call, working with a menu), the rest of the time the phone will be in standby mode and consume a few tenths of a watt.
We take out the calculator, we start counting - 15W * 24hours * 365days / 0.6 Efficiency = 219 kW * hour per year - according to the scheme “telephone + BP” one workplace eats 219 kilowatt-hours per year.
And all 225 places - 49.3 megawatt-hours per year.
When switched on according to the “PoE phone” scheme, I assumed conditionally that the switch consumes energy, but not phones - the switch consumes about 80 W (the working computer without frills consumes about 60 W, measured it itself), and then the switch controls the distribution of energy to the phones - total 80W * 24hours * 365 days / 0.96 (KPD) = 730 kW * h / year. 5 switches, sootv. - 3.65 MW * h / year
The difference in power consumption is 45.65 MW * h. At the then cost of lipidism, savings of ~ 170,000 rubles a year came out.
Total - 350 000 r - for the first year this model pays off.
This is in addition to the fact that it is almost impossible to connect additional electrical power to the building in defaultCity even for a bribe physically carried by one person, and the problem of power shortage is quite acute and frequent.
isp. materials -
www.nist.ru/hr/doc/gost/34-602-89.htm
www.altair.org/labnotes_POE.html
www.poweroverethernet.com
hp.com
Source: https://habr.com/ru/post/95361/
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