<?xml version="1.0" encoding="UTF-8"?>
<reference anchor="I-D.ietf-pce-stateful-hpce" target="https://datatracker.ietf.org/doc/html/draft-ietf-pce-stateful-hpce-10">
   <front>
      <title>Hierarchical Stateful Path Computation Element (PCE).</title>
      <author initials="D." surname="Dhody" fullname="Dhruv Dhody">
         <organization>Huawei Technologies</organization>
      </author>
      <author initials="Y." surname="Lee" fullname="Young Lee">
         <organization>Huawei Technologies</organization>
      </author>
      <author initials="D." surname="Ceccarelli" fullname="Daniele Ceccarelli">
         <organization>Ericsson</organization>
      </author>
      <author initials="J." surname="Shin" fullname="Jongyoon Shin">
         <organization>SK Telecom</organization>
      </author>
      <author initials="D." surname="King" fullname="Daniel King">
         <organization>Lancaster University</organization>
      </author>
      <date month="June" day="17" year="2019" />
      <abstract>
	 <t>   A Stateful Path Computation Element (PCE) maintains information on
   the current network state, including: computed Label Switched Path
   (LSPs), reserved resources within the network, and pending path
   computation requests. This information may then be considered when
   computing new traffic engineered LSPs, and for associated and
   dependent LSPs, received from Path Computation Clients (PCCs). The
   Path computation response from a PCE is helpful for the PCC to
   gracefully establish the computed LSP.

   The Hierarchical Path Computation Element (H-PCE) architecture,
   provides an architecture to allow the optimum sequence of
   inter-connected domains to be selected, and network policy to be
   applied if applicable, via the use of a hierarchical relationship
   between PCEs.

   Combining the capabilities of Stateful PCE and the Hierarchical PCE
   would be advantageous. This document describes general considerations
   and use cases for the deployment of Stateful, and not Stateless, PCEs
   using the Hierarchical PCE architecture.

	 </t>
      </abstract>
   </front>
   <seriesInfo name="Internet-Draft" value="draft-ietf-pce-stateful-hpce-10" />
   
</reference>
