Power over Ethernet | 78536Power over EthernetPower over Ethernet (PoE) is supported only on platforms: c sThis chapter contains the following major sections:• Configuring Power over Ethernet on page 786• Power Additional PoE Ports on the S-Series on page 794• Deploying VOIP on page 795FTOS supports Power over Ethernet (PoE), as described by IEEE 802.3af . IEEE 802.3af specifies that amaximum of 15.4 Watts can be transmitted to Ethernet devices over the signal pairs of an unshieldedtwisted pair (UTP) cable. PoE is useful in networks with IP phones and wireless access points becauseseparate power supplies for powered devices (PD) are not needed.Table 36-2 describes the classes of powered devices defined by IEEE 802.3af:FTOS supports PoE on all copper ports on the C-Series and on the S25V and S50V models of the S-Series.The C-Series and S-Series transmit power to connected IEEE 802.3af-compliant powered devices throughports that have been configured to supply PoE. Those platforms also support the protocols LLDP andLLDP-MED, which help optimize power distribution to PoE devices. See Chapter 46, Link LayerDiscovery Protocol, on page 861.Table 36-1. PoE Classes of Powered DevicesClassPower Range(Watts)ClassificationCurrent(mA)0 0.44 to 12.95 < 5.01 0.44 to 3.84 10.52 3.84 to 6.49 18.53 6.49 to 12.95 284 Reserved 40Note: FTOS treats Class 0, Class 3, and Class 4 powered devices the same. Class 4 is meant forIEEE802.3at compliant devices which require >12.95 Watts. Currently FTOS treats Class 4 devices asClass 3.
