the present invention provides a power negotiation protocol that enables pds and pses to negotiate the amount of inline power that a pd consumes and the corresponding pse provides . this power negotiation allows the pds provide fine - grained power consumption level to pses , and the pses are able to manage inline power efficiently using the negotiation protocol of the present invention . the pds can ask the pses for more power when needed rather than having to constantly reserve the maximum amount of power they can consume at all times . similarly , the pds can release reservation of excess power when their respective power requirements decrease . the pses can limit the amount of power that can be consumed by the pd , thereby providing the ability for an administrator to control how much power a given pd can consume .