1. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 1 © 2010 Cisco and/or its affiliates. All rights reserved. 1 Universal Power Over Ethernet - World’s First Power-Extended Network Rev 6 UABU Engineering 12/1/2010

2. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 2 Power over Ethernet basics Universal Power Over Ethernet (UPOE) LLDP based UPOE Forced 4-pair UPOE

3. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 3 © 2010 Cisco and/or its affiliates. All rights reserved. 3 Power Over Ethernet Basics

4. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 4 GLOSSARY: PoE – Power Over Ethernet DTE – Data Terminal Equipment PSE – Power Sourcing Equipment (eg: CAt4K Switch) PD – Powered Devices (end device receiving power) LLDP – Link Layer Discovery Protocol (Layer 2 protocol) ALT-A : IEEE Terminology for Signal pair – (1,2) & (3,6) on a RJ45 pinout ALT-B : IEEE Terminology for Spare pair – (4,5) & (7,8) on a RJ45 pinout

5. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 5 Power over Ethernet (PoE) Delivers DC Power and data over a Standard Copper Ethernet Cable(RJ45) Source: Fred Schindler, PoE Nerd lunch presentation

6. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 6 PoE/PoE+ is intended for DTE powering – to provide a 10Base-T, 100Base-T or 1000Base-T device with a single interface to both data it requires and power to process this data. PoE : IEEE 802.3af – Delivery of upto 15W of power over ALT A pairs of RJ45 PoE+ : IEEE 802.3at –Delivery of upto 30W of power over ALT A pairs of RJ45

7. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 7 Fig 1.Ethernet Data Transmission over RJ45 Fig 2. Overlaying Power with Data Figure 1 below shows the normal Data transmission between two PHY silicon. Figure 2 depicts how power is inserted along with data on ALT-A or ALT-B pairs to provide DTE powering. A power source introduces a port voltage “V” through the center tap of the Ethernet transformer. The end device in need of power, connects its load to the center tap of the Ethernet transformer to draw power from the source voltage “V”. This power does not affect the data since it is fed as a common-mode voltage.

8. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 8 Power is coupled from PSE to PD through a center tap transformer configuration Power is extracted on the PD side from center tap again and fed to a diode bridge The diode bridge is to ensure PD is polarity insensitive (see next slide). The diode bridge in turn feeds a PD chip which takes care of implementing the PD features. This configuration can provide upto 30W To double the power, the unused ALT B pairs (shown in the picture) are put to use as well. Simply by duplicating the circuitry shown on unused pairs upto 60W can be drawn. Source: Fred Schindler, PoE Nerd lunch presentation PD chip 50-57V

9. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 9 Source: Fred Schindler, PoE Nerd lunch presentation

10. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 10 Detection—is this a true PD device? Physical Layer Classification—how much power is required? (PoE - Type I) Power-on—provide the requested power (upto 12.95W is available at the PD). Data Link Layer Classification (LLDP) —refine the required power(more than 15.4W request and upto 30W – Poe+ - Type II). Source: Fred Schindler, PoE Nerd lunch presentation

11. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 11 DETECTION: Send Detection voltage pulse, measure current, Calculate R det = (V 1 -V 2 )/(I 1 -I 2 ) Valid Detection Signature? – Yes (IEEE802.3af/at define the valid and invalid ranges) CLASSIFICATION: Send Classification Voltage pulse, measure current (Physical layer classification) Valid Classification signature? – Yes (IEEE802.3af/at define the valid and invalid ranges) POWER ON: Turn on power

12. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 12 ParameterUnitMin max Power turn on timems400 Inrush current(startup mode) mA400450 Inrush timems5075 IEEE 802.3at defines all the parameters related to power on, power monitoring and related timing etc for PoE/PoE+ This is to ensure safety and proper operation for a PoE powered network The table below shows some key parameters. Ie Inrush control and Power on time Refer to IEEE802.3at for a detailed list and explanation

13. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 13 Upper limit due to: - component limits - safety Lower limit: - supports the maximum average PD demand Short Circuit limit -PSE protection PD Surge Allowance (~15%)

14. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 14 DC Disconnect - Decided based on maintain power signature -If PD current draw is in the range of I min for greater than T MPDO -After power removal – PSE goes back to start of state machine (detection state) ParameterSymbolUnitMinMax IDLE state currentIminmA05 PD maintain power signature dropout time Tmpdoms300400

15. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 15 Cisco Confidential © 2010 Cisco and/or its affiliates. All rights reserved. 15 Universal Power Over Ethernet

16. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 16

17. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 17 Replicate the same ALT-A HW circuitry on the unused ALT B pairs Upto 60W delivery using all the 4-pairs on cat5e Even under worst case (100m cable) 51W available at PD Cisco’s proprietary UPOE defines two power up mechanisms  LLDP based (preferred)  Forced 4-pair PDChip 50-57V

18. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 18 Cisco Confidential © 2010 Cisco and/or its affiliates. All rights reserved. 18 LLDP based UPOE

19. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 19 LLDP – Link Layer Discovery Protocol LLDP is a layer 2 protocol in Networking. It is vendor-neutral and used for advertising identity, capabilities and neighbours on a LAN LLDP uses Type, Length and Value fields(TLV) to convey the information

20. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 20 IEEE 802.3at already defines LLDP for power negotiation greater than 15.4W and upto 30W. UPOE uses the same negotiation method to provide upto 60W contingent on a successful 4-pair handshake. IEEE802.3at LLDP format is shown below. “4-wire Power Via MDI” - is the new subtype for Cisco specific OUI TLV. It is present in all modes of operation and is used to exchange 4-pair capabilities before enabling 4pair and providing upto 60W.

21. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 21 TLV typeTLV information String Length Cisco OUI Identifier Cisco OUI subtype PSE/PD capabilities 7 bits9bits3 octets1 octet1 octet TLV type-127(organisation specific) Information string length = 5 (bytes) Cisco OUI Identifier = 00-01-42 Cisco OUI subtype = 1 BitFunctionValue/Meaning 0UPOE supported0=No 1=Yes 1ALT-B pair Detection/Classification Required 0=No 1=Yes 2PD ALT-B pair desired state0=No 1=Yes 3PSE ALT-B pair operational state 0=Disabled 1=Enabled 4:7Reserved

22. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 22 NOTE: This is an example for independent PD architecture – Actual handshake will depend on the PD architecture

23. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 23 Cisco Confidential © 2010 Cisco and/or its affiliates. All rights reserved. 23 Forced 4-pair UPOE

24. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 24 To support already deployed devices which don’t have LLDP capabilities Physical layer signature is a must on both ALT-A and ALT-B pairs. This is used in lieu of LLDP to detect UPOE end device. Least Preferred – Doesn’t support the advantages that come with LLDP. For instance, In LLDP if a UPOE port drops down in power consumption this extra power can now be returned to general pool for use by other ports. Forced 4-pair implementation doesn’t support this – power allocation to a forced 4-pair port is static at 60W By Default UPOE switch uses LLDP – to turn on forced 4-pair a CLI command is provided => “power inline four-pair forced”

25. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 25

26. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 26

27. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 27 RJ45 1234567812345678 Diode Bridge PD chip(s) DC-DC Vout Vout_rtn Power Path Data Path Input 50-57V

28. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 28 For Utilizing UPOE the end device should have the following  A IEEE802.3at compliant Powered Device (PD) circuit (ALT-A and ALT-B pairs could combine before and feed into a single PD chip if LLDP capabilities are present; However if forced UPOE is needed then a compliant PD chip would be needed on both ALT-A and ALT-B pairs)  LLDP implementation of Cisco 4-pair power via MDI TLV  LLDP TLV for power negotiation NOTE: In absence of LLDP forced 4-pair can be utilized but this method is not the preferred method of implemention. If LLDP implementation is possible the end device is advised to take that route.

29. © 2010 Cisco and/or its affiliates. All rights reserved. Cisco Confidential 29 Thank you.