Internet Engineering Task Force Georgios Karagiannis Internet-Draft University of Twente Intended status: Experimental Anurag Bhargava Expires: April 12, 2013 Cisco Systems, Inc. October 12, 2012 Generic Aggregation of Resource ReSerVation Protocol (RSVP) for IPv4 And IPv6 Reservations over PCN domains draft-ietf-tsvwg-rsvp-pcn-03 Abstract This document specifies the extensions to the Generic Aggregated RSVP [RFC4860] for support of the PCN Controlled Load (CL) and Single Marking (SM) edge behaviors over a Diffserv cloud using Pre- Congestion Notification. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 12, 2013. Karagiannis, et al. Expires April 12, 2013 [Page 1] Internet-Draft Aggregated RSVP over PCN October 2012 Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 2. Overview of RSVP extensions and Operations . . . . . . . . . . . 10 2.1 Overview of RSVP Aggregation Procedures in PCN domains . . . . . 10 2.1.1 PCN Marking and encoding and transport of pre-congestion Information . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.1.2. Traffic Classification Within The Aggregation Region . . . . 12 2.1.3. Deaggregator (PCN-egress-node) Determination . . . . . . . . 12 2.1.4. Mapping E2E Reservations Onto Aggregate Reservations . . . . 12 2.1.5. Size of Aggregate Reservations . . . . . . . . . . . . . . . 12 2.1.6. E2E Path ADSPEC update . . . . . . . . . . . . . . . . . . . 13 2.1.7. Intra-domain Routes . . . . . . . . . . . . . . . . . . . . . 13 2.1.8. Inter-domain Routes . . . . . . . . . . . . . . . . . . . . . 13 2.1.9. Reservations for Multicast Sessions . . . . . . . . . . . . . 13 2.1.10. Multi-level Aggregation . . . . . . . . . . . . . . . . . . 13 2.1.11. Reliability Issues . . . . . . . . . . . . . . . . . . . . . 13 2.1.12. Message Integrity and Node Authentication . . . . . . . . . 13 3. Elements of Procedure . . . . . . . . . . . . . . . . . . . . . . 13 3.1. Receipt of E2E Path Message By PCN-ingress-node (aggregating router) . . . . . . . . . . . . . . . . . . . . . . 13 3.2. Handling Of E2E Path Message By Interior Routers . . . . . . . 14 3.3. Receipt of E2E Path Message By PCN-egress-node (deaggregating router) . . . . . . . . . . . . . . . . . . . . . 15 3.4. Initiation of new Aggregate Path Message By PCN-ingress-node (Aggregating Router) . . . . . . . . . . . . . . . . . . . . . 15 3.5. Handling Of new Aggregate Path Message By Interior Routers . . 15 3.6. Handling of E2E Resv Message by Deaggregating Router . . . . . 15 3.7. Handling Of E2E Resv Message By Interior Routers . . . . . . . 15 3.8. Initiation of New Aggregate Resv Message By Deaggregating Router 15 Karagiannis, et al. Expires April 12, 2013 [Page 2] Internet-Draft Aggregated RSVP over PCN October 2012 3.9. Handling of Aggregate Resv Message by Interior Routers . . . . 16 3.10. Handling of E2E Resv Message by Aggregating Router . . . . . . 16 3.11. Handling of Aggregated Resv Message by Aggregating Router . . 16 3.12. Removal of E2E Reservation . . . . . . . . . . . . . . . . . . 17 3.13. Removal of Aggregate Reservation . . . . . . . . . . . . . . . 17 3.14. Handling of Data On Reserved E2E Flow by Aggregating Router . 17 3.15. Procedures for Multicast Sessions . . . . . . . . . . . . . . 17 4. Protocol Elements . . . . . . . . . . . . . . . . . . . . . . . . 17 4.1 PCN object . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5. Security Considerations . . . . . . . . . . . . . . . . . . . . . 23 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 23 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 23 8. Normative References . . . . . . . . . . . . . . . . . . . . . . 23 9. Informative References . . . . . . . . . . . . . . . . . . . . . 24 10. Authors' Address . . . . . . . . . . . . . . . . . . . . . . . . 25 Karagiannis, et al. Expires April 12, 2013 [Page 3] Internet-Draft Aggregated RSVP over PCN October 2012 1. Introduction Two main Quality of Service (QoS) architectures have been specified by the IETF. These are the Integrated Services (Intserv) [RFC1633] architecture and the Differentiated Services (DiffServ) architecture ([RFC2475]). Intserv provides methods for the delivery of end-to-end Quality of Service (QoS) to applications over heterogeneous networks. One of the QoS signaling protocols used by the Intserv architecture is the Resource reServation Protocol (RSVP) [RFC2205], which can be used by applications to request per-flow resources from the network. These RSVP requests can be admitted or rejected by the network. Applications can express their quantifiable resource requirements using Intserv parameters as defined in [RFC2211] and [RFC2212]. The Controlled Load (CL) service [RFC2211] is a quality of service (QoS) closely approximating the QoS that the same flow would receive from a lightly loaded network element. The CL service is useful for inelastic flows such as those used for real-time media. The DiffServ architecture can support the differentiated treatment of packets in very large scale environments. While Intserv and RSVP classify packets per-flow, Diffserv networks classify packets into one of a small number of aggregated flows or "classes", based on the Diffserv codepoint (DSCP) in the packet IP header. At each Diffserv router, packets are subjected to a "per-hop behavior" (PHB), which is invoked by the DSCP. The primary benefit of Diffserv is its scalability, since the need for per-flow state and per-flow processing, is eliminated. However, DiffServ does not include any mechanism for communication between applications and the network. Several solutions have been specified to solve this issue. One of these solutions is Intserv over Diffserv [RFC2998] including resource-based admission control, policy-based admission control, assistance in traffic identification/classification, and traffic conditioning. Intserv over Diffserv can operate over a statically provisioned Diffserv region or RSVP aware. When it is RSVP aware, several mechanisms may be used to support dynamic provisioning and topology- aware admission control, including aggregate RSVP reservations, per- flow RSVP, or a bandwidth broker. [RFC3175] specifies aggregation of Resource ReSerVation Protocol (RSVP) end-to-end reservations over aggregate RSVP reservations. In [RFC3175] the RSVP aggregated reservation is characterized by a RSVP SESSION object using the 3-tuple . Several scenarios require the use of multiple generic aggregate reservations that are established for a given PHB from a given source IP address to a given destination IP address, see [RFC4860], [SIG-NESTED]. Karagiannis, et al. Expires April 12, 2013 [Page 4] Internet-Draft Aggregated RSVP over PCN October 2012 For example, multiple generic aggregate reservations can be applied in the situation that multiple e2e reservations using different preemption priorities need to be aggregated through a PCN- domain using the same PHB. By using multiple aggregate reservations for the same PHB allows enforcement of the different preemption priorities within the aggregation region. This allows more efficient management of the Diffserv resources, and in periods of resource shortage, this allows sustainment of a larger number of E2E reservations with higher preemption priorities. In particular, [SIG-NESTED] discusses in detail how end-to-end RSVP reservations can be established in a nested VPN environment through RSVP aggregation. [RFC4860] provides generic aggregate reservations by extending [RFC3175] to support multiple aggregate reservations for the same source IP address, destination IP address, and PHB (or set of PHBs). In particular, multiple such generic aggregate reservations can be established for a given PHB from a given source IP address to a given destination IP address. This is achieved by adding the concept of a Virtual Destination Port and of an Extended Virtual Destination Port in the RSVP SESSION object. In addition to this, the RSVP SESSION object for generic aggregate reservations uses the PHB Identification Code (PHB-ID) defined in [RFC3140], instead of using the Diffserv Code Point (DSCP) used in [RFC3175]. The PHB-ID is used to identify the PHB, or set of PHBs, from which the Diffserv resources are to be reserved. The main objective of Pre-Congestion Notification (PCN) is to support the quality of service (QoS) of inelastic flows within a Diffserv domain in a simple, scalable, and robust fashion. Two mechanisms are used: admission control, to decide whether to admit or block a new flow request, and (in abnormal circumstances) flow termination to decide whether to terminate some of the existing flows. To achieve this, the overall rate of PCN-traffic is metered on every link in the PCN-domain, and PCN-packets are appropriately marked when certain configured rates are exceeded. These configured rates are below the rate of the link thus providing notification to PCN-boundary-nodes about incipient overloads before any congestion occurs (hence the "pre" part of "pre-congestion notification"). The level of marking allows decisions to be made about whether to admit or terminate PCN- flows. The PCN-egress-nodes measure the rates of differently marked PCN-traffic in periodic intervals and report these rates to the decision points for admission control and flow termination, based on which they take their decisions. The decision points may be collocated with the PCN-ingress-nodes or their function may be implemented in a centralized node. For more details see [RFC5559], [RFC6661], [RFC6662]. In this document it is considered that the decision point is collocated with the PCN-ingress-node. Karagiannis, et al. Expires April 12, 2013 [Page 5] Internet-Draft Aggregated RSVP over PCN October 2012 This document follows the PCN signaling requirements defined in [RFC6663] and specifies the extensions to the Generic Aggregated RSVP [RFC4860] for the support of PCN edge behaviors as specified in [RFC6661] and [RFC6662]. Moreover, this document specifies how RSVP aggregation can be used to setup and maintain: (1) Ingress Egress Aggregate (IEA) states at Ingress and Egress nodes and (2) generic aggregation of RSVP end-to- end RSVP reservations over PCN (Congestion and Pre-Congestion Notification) domains. This document, and according to [RFC4860] MAY also be used end-to-end directly by end-systems attached to a Diffserv network. Furthermore, this document and according to [RFC4860], in absence of e2e RSVP flows, a variety of policies (not defined in this document) can be used at the Aggregator to set the DSCP of packets passing into the aggregation region and how they are mapped onto generic aggregate reservations. These policies are not described in this document but are a matter of local configuration. In this document it is considered that the PCN-nodes MUST be able to support the functionality specified in [RFC5670], [RFC5559], [RFC6660], [RFC6661], [RFC6662]. Furthermore, the PCN-boundary-nodes MUST support the RSVP generic aggregated reservation procedures specified in [RFC4860] which are augmented with procedures specified in this document. 1.1. Terminology This document uses terms defined in [RFC4860], [RFC3175], [RFC5559], [RFC5670], [RFC6661], [RFC6662]. For readability, a number of definitions from [RFC3175] as well as definitions for terms used in [RFC5559], [RFC6661], and [RFC6662] are provided here, where some of them are augmented with new meanings: Aggregator This is the process in (or associated with) the router at the ingress edge of the aggregation region (with respect to the end-to-end RSVP reservation) and behaving in accordance with [RFC4860]. In this document, it is also the PCN-ingress-node and the decision point. Deaggregator This is the process in (or associated with) the router at the egress edge of the aggregation region (with respect to the end-to-end RSVP reservation) and behaving in accordance with [RFC4860]. In this document, it is also the PCN-egress-node. E2E (or e2e) end to end Karagiannis, et al. Expires April 12, 2013 [Page 6] Internet-Draft Aggregated RSVP over PCN October 2012 E2E Reservation This is an RSVP reservation such that: (i) corresponding RSVP Path messages are initiated upstream of the Aggregator and terminated downstream of the Deaggregator, and (ii) corresponding RSVP Resv messages are initiated downstream of the Deaggregator and terminated upstream of the Aggregator, and (iii) this RSVP reservation is aggregated over an Ingress Egress Aggregate (IEA) between the Aggregator and Deaggregator. An E2E RSVP reservation may be a per-flow reservation, which in this document is only maintained at the PCN-ingress-node and PCN-egress- node. Alternatively, the E2E reservation may itself be an aggregate reservation of various types (e.g., Aggregate IP reservation, Aggregate IPsec reservation, see [RFC4860]). As per regular RSVP operations, E2E RSVP reservations are unidirectional. PHB-ID (Per Hop Behavior Identification Code) A 16-bit field containing the Per Hop Behavior Identification Code of the PHB, or of the set of PHBs, from which Diffserv resources are to be reserved. This field MUST be encoded as specified in Section 2 of [RFC3140]. VDstPort (Virtual Destination Port) A 16-bit identifier used in the SESSION that remains constant over the life of the generic aggregate reservation. Extended vDstPort (Extended Virtual Destination Port) An identifier used in the SESSION that remains constant over the life of the generic aggregate reservation. The length of this idenitifier is 32- bits when IPv4 addresses are used and 128 bits when IPv6 addresses are used. A sender(or Aggregator) that wishes to narrow the scope of a SESSION to the sender-receiver pair (or Aggregator-Deaggregator pair) SHOULD place its IPv4 or IPv6 address here as a network unique identifier. A sender (or Aggregator) that wishes to use a common session with other senders (or Aggregators) in order to use a shared reservation across senders (or Aggregators) MUST set this field to all zeros. In this document, the Extended vDstPort SHOULD contain the IPv4 or IPv6 address of the Aggregator. Karagiannis, et al. Expires April 12, 2013 [Page 7] Internet-Draft Aggregated RSVP over PCN October 2012 PCN-domain: a PCN-capable domain; a contiguous set of PCN-enabled nodes that perform Diffserv scheduling [RFC2474]; the complete set of PCN-nodes that in principle can, through PCN-marking packets, influence decisions about flow admission and termination for the PCN-domain; includes the PCN-egress-nodes, which measure these PCN-marks, and the PCN-ingress-nodes. PCN-boundary-node: a PCN-node that connects one PCN-domain to a node either in another PCN-domain or in a non-PCN-domain. PCN-interior-node: a node in a PCN-domain that is not a PCN- boundary-node. PCN-node: a PCN-boundary-node or a PCN-interior-node. PCN-egress-node: a PCN-boundary-node in its role in handling traffic as it leaves a PCN-domain. PCN-ingress-node: a PCN-boundary-node in its role in handling traffic as it enters a PCN-domain. In this document the PCN-ingress-node operates also as a Decision Point and aggregator. PCN-traffic, PCN-packets, PCN-BA: a PCN-domain carries traffic of different Diffserv behavior aggregates (BAs) [RFC2474]. The PCN-BA uses the PCN mechanisms to carry PCN-traffic, and the corresponding packets are PCN-packets. The same network will carry traffic of other Diffserv BAs. The PCN-BA is distinguished by a combination of the Diffserv codepoint (DSCP) and ECN fields. Microflow: a single instance of an application-to-application (from [RFC2474]) flow of packets which is identified by source address, destination address, protocol id, and source port, destination port (where applicable). e2e microflow a microflow where its associated packets are being forwarded on an E2E path. PCN-flow: the unit of PCN-traffic that the PCN-boundary-node admits (or terminates); the unit could be a single e2e microflow (as defined in [RFC2474]) or some identifiable collection of microflows. Karagiannis, et al. Expires April 12, 2013 [Page 8] Internet-Draft Aggregated RSVP over PCN October 2012 RSVP generic aggregated reservation: an RSVP reservation that is identified by using the RSVP SESSION object for generic RSVP aggregate reservation. This RSVP SESSION object is based on the RSVP SESSION object specified in [RFC4860] augmented with the following information: o) the IPv4 DestAddress, IPv6 DestAddress SHOULD be set to the IPv4 or IPv6 destination addresses, respectively, of the Deaggregator (PCN-egress- node) o) PHB-ID (Per Hop Behavior Identification Code) SHOULD be set equal to PCN-compatible Diffserv codepoint(s). o) Extended vDstPort SHOULD be set to the IPv4 or IPv6 destination addresses, of the Aggregator (PCN-ingress-node) Ingress-egress-aggregate (IEA): The collection of PCN-packets from all PCN-flows that travel in one direction between a specific pair of PCN-boundary-nodes. An ingress- egress-aggregate is identified by the combination of (1) fields), (2) IP addresses of the specific pair of PCN-boundary-nodes used by a ingress-egress-aggregate. In this document one RSVP generic aggregated reservation is mapped to only one ingress-egress-aggregate, while one ingress-egress- aggregate is mapped to either one or to more than one RSVP generic aggregated reservations. PCN-admission-state The state ("admit" or "block") derived by the Decision Point for a given ingress-egress-aggregate based on statistics about PCN-packet marking. The Decision Point decides to admit or block new flows offered to the aggregate based on the current value of the PCN-admission-state. Congestion level estimate (CLE) The ratio of PCN-marked to total PCN-traffic (measured in octets) received for a given ingress- egress-aggregate during a given measurement period. The CLE is used to derive the PCN-admission-state and is also used by the report suppression procedure if report suppression is activated. t_meas A configurable time interval that defines the measurement period over which the PCN-egress-node collects statistics relating to PCN-traffic marking. Karagiannis, et al. Expires April 12, 2013 [Page 9] Internet-Draft Aggregated RSVP over PCN October 2012 t_maxsuppress A configurable time interval after which the PCN-egress-node MUST send a report to the Decision Point for a given ingress-egress-aggregate regardless of the most recent values of the CLE. This mechanism provides the Decision Point with a periodic confirmation of liveness when report suppression is activated. t_fail An interval after which the Decision Point concludes That communication from a given PCN-egress-node has failed if it has received no reports from the PCN-egress-node during that interval. t_crit A configurable interval used in the calculation of T_fail. t-recvFail An ingress-egress-aggregate timer that is used at The Decision point (in this document at the PCN- ingress-node) which when expires raises an alarm to management, and activates the PCN-ingress-node to block the admission of new PCN-flows. This timer expires when it value is equal to T-fail and is reset when a report, i.e., RSVP aggregated RESV message, is received for a RSVP generic aggregated reservation (which is matched to one ingress-egress-aggregate). 2. Overview of RSVP extensions and Operations 2.1 Overview of RSVP Aggregation Procedures in PCN domains The PCN-boundary-nodes, see Figure 1, can support RSVP SESSIONS for generic aggregated reservations {RFC4860], which are depending on ingress-egress-aggregates. In particular, one RSVP generic aggregated reservation matches to only one ingress-egress-aggregate. However, one ingress-egress-aggregate matches to either one or to more than one RSVP generic aggregated reservations. In addition, in this document it is considered that the PCN-boundary nodes are able to distinguish and process (1) RSVP SESSIONS for generic aggregated sessions and their messages according to [RFC4860], (2) e2e RSVP sessions and messages according to [RFC2205]. Furthermore, it is considered that the PCN-interior-nodes are not able to distinguish neither RSVP generic aggregated sessions and their associated messages [RFC4860], nor e2e RSVP sessions and their associated messages [RFC2205]. Karagiannis, et al. Expires April 12, 2013 [Page 10] Internet-Draft Aggregated RSVP over PCN October 2012 -------------------------- / PCN-domain \ |----| | | |----| H--| R |\ |-----| |------| /| R |-->H H--| |\\| | |---| |---| | |//| |-->H |----| \| | | I | | I | | |/ |----| | Agg |======================>| Deag | /| | | | | | | |\ H--------//| | |---| |---| | |\\-------->H H--------/ |-----| |------| \-------->H | | \ / -------------------------- H = Host requesting end-to-end RSVP reservations R = RSVP router Agg = Aggregator (PCN-ingress-node) Deag = Deaggregator (PCN-egress-node) I = Interior Router (PCN-interior-node) --> = E2E RSVP reservation ==> = Aggregate RSVP reservation Figure 1 : Aggregation of E2E Reservations over Generic Aggregate RSVP Reservations in PCN domains, based on [RFC4860] Moreover, each Aggregator and Deaggregator (i.e., PCN-boundary-nodes) MUST support policies to initiate and maintain for each pair of PCN-boundary-nodes of the same PCN-domain (1) one ingress-egress- aggregate and (2) either one or more RSVP generic aggregated reservations. Note that one RSVP generic aggregated reservation matches to only one ingress-egress-aggregate, while one ingress- egress-aggregate matches to either one or to more than one RSVP generic aggregated reservations. This can be accomplished by using for the different RSVP generic aggregated reservations the same combinations of ingress and egress identifiers, but with a different PHB-ID value (see [RFC4860]). Depending on a policy the Aggregator SHOULD be able to decide whether an e2e microflow (i.e., PCN-flow) can be mapped into (1) one RSVP generic aggregated reservation and (2) one ingress-egress-aggregate maintained by the Aggregator (i.e., PCN-ingress-node). Note that each RSVP generic aggregated reservation is identified by using the RSVP SESSION object [RFC4860]. The RSVP SESSION object for generic aggregate reservations is based on the RSVP SESSION object specified in [RFC4860] augmented with the following information: o) the IPv4 DestAddress, IPv6 DestAddress SHOULD be set to the IPv4 or IPv6 destination addresses, respectively, of the Deaggregator (PCN-egress-node) o) PHB-ID (Per Hop Behavior Identification Code) SHOULD be set equal to PCN-compatible Diffserv codepoint(s). Karagiannis, et al. Expires April 12, 2013 [Page 11] Internet-Draft Aggregated RSVP over PCN October 2012 o) Extended vDstPort SHOULD be set to the IPv4 or IPv6 destination addresses, of the Aggregator (PCN-ingress-node) 2.1.1 PCN Marking and encoding and transport of pre-congestion information The method of PCN marking within the PCN domain is based on [RFC5670]. In addition, the method of encoding and transport of pre- congestion information is based [RFC6660]. The PHB-ID (Per Hop Behavior Identification Code) used, SHOULD be set equal to PCN-compatible Diffserv codepoint(s). 2.1.2. Traffic Classification Within The Aggregation Region The PCN-traffic is marked using PCN-marking and is classified using The PCN-BA (i.e., combination of the DSCP and ECN fields). The PCN-traffic (e.g., e2e microflows) belonging to an ingress- egress-aggregate can be classified only at the PCN-boundary-nodes using the combination of (1) PCN-BA (i.e., combination of the DSCP and ECN fields), (2) IP addresses of the specific pair of PCN- boundary-nodes used by a ingress-egress-aggregate. The method of classification and traffic conditioning of PCN-traffic and non-PCN traffic and PHB configuration is described in [RFC6661] and [RFC6662]. Moreover, the PCN-traffic (e.g., e2e microflows) belonging to a RSVP generic aggregated reservation can be classified only at the PCN-boundary-nodes (i.e., Aggregator and Deaggregator) by using the RSVP SESSION object for RSVP generic aggregated reservations, see [RFC4860]. 2.1.3. Deaggregator (PCN-egress-node) Determination In this document it is considered that for the determination of the Deaggregator, the same methods can be used as the ones described in [RFC4860]. 2.1.4. Mapping E2E Reservations Onto Aggregate Reservations In this document it is considered that for the mapping of e2e reservations onto aggregate reservations, the same methods can be used as the ones described in [RFC4860], augmented by the following rules: o) PCN-ingress-node MUST use one or more policies to estimate whether an e2e RSVP reservation session associated with an e2e Path message that arrives at the external interface of the PCN-ingress- node can be mapped onto an existing RSVP generic aggregation reservation state. 2.1.5. Size of Aggregate Reservations In this document it is considered that for the determination of the size of the RSVP generic aggregate reservations, the same methods can be used as the ones described in [RFC4860]. Karagiannis, et al. Expires April 12, 2013 [Page 12] Internet-Draft Aggregated RSVP over PCN October 2012 2.1.6. E2E Path ADSPEC update In this document it is considered that for the update of the e2e Path ADSPEC, the same methods can be used as the ones described in [RFC4860]. 2.1.7. Intra-domain Routes The PCN-interior-nodes are neither maintaining e2e RSVP nor RSVP generic aggregation states and reservations. Therefore, intra-domain route changes will not affect intra-domain reservations since such reservations are not maintained by the PCN-interior-nodes. 2.1.8. Inter-domain Routes In this document it is considered that for the solving the issues caused by the inter-domain route changes, the same methods can be used as the ones described in [RFC4860]. 2.1.9. Reservations for Multicast Sessions PCN does not consider reservations for multicast sessions. 2.1.10. Multi-level Aggregation PCN does not consider multi-level aggregations within the PCN domain. 2.1.11. Reliability Issues In this document it is considered that for solving possible reliability issues, the same methods can be used as the ones described in [RFC4860]. 2.1.12. Message Integrity and Node Authentication In this document it is considered that for message integrity and node authentication, the same methods can be used as the ones described in [RFC4860] and [RFC5559]. 3. Elements of Procedure This section describes the procedures used to implement the aggregated RSVP procedure over PCN. 3.1. Receipt of E2E Path Message By PCN-ingress-node (aggregating router) When the e2e RSVP message arrives at the exterior interface of the Aggregator, i.e., PCN-ingress-node, then standard RSVP generic aggregation [RFC4860] procedures are used, augmented with the following rules: Karagiannis, et al. Expires April 12, 2013 [Page 13] Internet-Draft Aggregated RSVP over PCN October 2012 o) The e2e RSVP reservation session associated with an e2e Path message that arrives at the external interface of the PCN- ingress-node is mapped/matched onto an existing RSVP generic aggregation reservation state. o) If the timer t-recvFail expires for a given PCN-egress-node, the Decision Point (i.e., PCN-ingress-node) SHOULD NOT allow the e2e microflow (i.e., PCN-flow) to be admitted to that RSVP generic aggregated reservation (which is matched to one ingress-egress-aggregate). The admission or rejection procedure of a PCN-flow into the PCN-domain is defined in detail in: [RFC6661] and [RFC6662]. If the Aggregator is not able to admit the e2e microflow it SHOULD then generate an e2e PathErr message using standard e2e RSVP procedures [RFC4495]. This e2e PathErr message is sent to the originating sender of the e2e Path message. A new error code "PCN-domain rejects e2e reservation" MUST be augmented to the RSVP error codes to inform the sender that a PCN domains rejects the e2e reservation request. o) If the timer t-recvFail does NOT expire for a given PCN-egress- node, then: o) If (1) the PCN-admission state for the ingress-egress- aggregate associated with the received e2e Path and (2) the state for the selected RSVP generic aggregated reservation, see [RFC4860], are "admit", the Decision Point (i.e., PCN- ingress-node) SHOULD allow the new flow to be admitted to that RSVP generic aggregated reservation. The e2e Path message is then forwarded towards destination. o) If for the same ingress-egress-aggregated and the same RSVP generic aggregated reservation then (1) the PCN-admission- state and/or (2) the state for the RSVP generic aggregated reservation are/is "block", the flow SHOULD NOT be admitted by the Aggregator and an e2e PathErr message SHOULD be generated, using standard e2e RSVP procedures [RFC4495]. This e2e PathErr message is sent to the originating sender of the e2e Path message, using standard e2e RSVP procedures [RFC2205], [RFC4495]. A new error code "PCN-domain rejects e2e reservation" MUST be augmented to the RSVP error codes to inform the sender that a PCN domains rejects the e2e reservation request. The way of how the PCN-admission-state is maintained is specified in [RFC6661] and [RFC6662]. The way of how the RSVP generic aggregated reservation state is maintained is specified in [RFC4860]. 3.2. Handling Of E2E Path Message By Interior Routers The e2e Path messages traverse zero or more PCN-interior-nodes. Karagiannis, et al. Expires April 12, 2013 [Page 14] Internet-Draft Aggregated RSVP over PCN October 2012 The PCN-interior-nodes receive the e2e Path message on an interior interface and forward it on another interior interface. The e2e Path messages are simply forwarded as normal IP datagrams. 3.3. Receipt of E2E Path Message By PCN-egress-node (deaggregating router) When receiving the e2e Path message the PCN-egress-node (Deaggregator) performs main regular [RFC4860] procedures, augmented with the following rules, see also [draft-lefaucheur-rsvp-ecn-01]: o) The PCN-egress-node MUST NOT perform the RSVP-TTL vs IP TTL- check and MUST NOT update the ADspec Break bit. This is because the whole PCN-domain is effectively handled by e2e RSVP as a virtual link on which integrated service is indeed supported (and admission control performed) so that the Break bit MUST NOT be set. The PCN-egress-nodes forwards the e2e Path message towards the receiver. 3.4. Initiation of new Aggregate Path Message By PCN-ingress-node (Aggregating Router) In this document it is considered that for the initiation of the new RSVP aggregated Path message by the PCN-ingress-node (Aggregator), the same methods can be used as the ones described in [RFC4860]. 3.5. Handling Of new Aggregate Path Message By Interior Routers The Aggregate Path messages traverse zero or more PCN-interior-nodes. The PCN-interior-nodes receive the e2e Path message on an interior interface and forward it on another interior interface. The Aggregated Path messages are simply forwarded as normal IP datagrams. 3.6. Handling of E2E Resv Message by Deaggregating Router When the e2e Resv message arrives at the exterior interface of the Deaggregator, i.e., PCN-egress-node, then standard RSVP aggregation [RFC4860] procedures are used. 3.7. Handling Of E2E Resv Message By Interior Routers The e2e Resv messages traverse zero or more PCN-interior-nodes. The PCN-interior-nodes receive the e2e Resv message on an interior interface and forward it on another interior interface. The e2e Resv messages are simply forwarded as normal IP datagrams. 3.8. Initiation of New Aggregate Resv Message By Deaggregating Router In this document it is considered that for the initiation of the new RSVP aggregated Resv message by the PCN-ingress-node (Aggregator), the same methods can be used as the ones described in [RFC4860] augmented with the following rules: Karagiannis, et al. Expires April 12, 2013 [Page 15] Internet-Draft Aggregated RSVP over PCN October 2012 o) At the end of each t-meas measurement interval, or less frequently if "optional report suppression" is activated, see [RFC6661], and [RFC6662], the PCN-egress-node MUST include the new PCN object that will be sent to the associated Decision Point (i.e., PCN-ingress-node). The PCN object is specified in this document and is used for the report of the data measured by the PCN-egress-node, for a particular ingress-egress-aggregate, see [RFC6661], and [RFC6662]. The address of the PCN-ingress- node is the one specified in the same ingress-egress-aggregate. 3.9. Handling of Aggregate Resv Message by Interior Routers The Aggregated Resv messages traverse zero or more PCN-interior- nodes. The PCN-interior-nodes receive the Aggregated Resv message on an interior interface and forward it on another interior interface. The Aggregated Resv messages are simply forwarded as normal IP datagrams. 3.10. Handling of E2E Resv Message by Aggregating Router When the e2e Resv message arrives at the interior interface of the Aggregating router, i.e., PCN-ingress-node, then standard RSVP aggregation [RFC4860] procedures are used. 3.11. Handling of Aggregated Resv Message by Aggregating Router When the Aggregated Resv message arrives at the interior interface of the Aggregating router, i.e., PCN-ingress-node, then standard RSVP aggregation [RFC4860] procedures are used, augmented with the following rules: o) the Decision Point (i.e., the PCN-ingress-node) SHOULD use the information carried by the PCN objects as specified in [RFC6661], [RFC6662]. When the Aggregator (i.e., PCN-ingress-node) needs to terminate an amount of traffic associated to one ingress-egress-aggregate (see bullet 2 in Section 3.3.2 of [RFC6661] and [RFC6662]), then several procedures of terminating e2e microflows can be deployed. The default procedure of terminating e2e microflows (i.e., PCN-flows) is as follows, see e.g., [RFC6661]. For the same ingress-egress-aggregate, select a number of e2e microflows to be terminated in order to decrease the total incoming amount of bandwidth associated with one ingress-egress-aggregate by the amount of traffic to be terminated, see above. In this situation the same mechanisms for terminating an e2e microflow can be followed as specified in [RFC2205]. However, based on a local policy, the Aggregator could use other procedures of terminating microflows. Karagiannis, et al. Expires April 12, 2013 [Page 16] Internet-Draft Aggregated RSVP over PCN October 2012 For example, for the same ingress-egress-aggregate, select a number of e2e microflows to be terminated or to reduce their reserved bandwidth in order to decrease the total incoming amount of bandwidth associated with one ingress-egress-aggregate by the amount of traffic to be terminated. In this situation the same mechanisms for terminating an e2e microflow or reducing bandwidth associated with an e2e microflow can be followed as specified in [RFC4495]. 3.12. Removal of E2E Reservation In this document it is considered that for the removal of e2e reservations, the same methods can be used as the ones described in [RFC4860] and [RFC4495]. 3.13. Removal of Aggregate Reservation In this document it is considered that for the removal of RSVP generic aggregated reservations, the same methods can be used as the ones described in [RFC4860]. 3.14. Handling of Data On Reserved E2E Flow by Aggregating Router The handling of data on the reserved e2e Flow by Aggregating Router is using the procedures described in [RFC4860] augmented with: o) Regarding, PCN marking and traffic classification the procedures defined in Section 2.1.1 and 2.1.3 of this document are used. 3.15. Procedures for Multicast Sessions In this document no multicast sessions are considered. 4. Protocol Elements The protocol elements in this document are using the protocol Elements defined in [RFC4860], augmented with the following rules: o) A PCN-egress-node (i.e., Deaggregator) SHOULD send periodically and at the end of each t-meas measurement interval, or less frequently if "optional report suppression" is activated, an (refresh) aggregated RSVP message to the PCN-ingress-node (i.e. aggregator). o) the DSCP value included in the SESSION object, SHOULD be set equal to a PCN-compatible Diffserv codepoint. o) An aggregated Resv message MUST carry one or more C-type PCN objects, see Section 4.1, to report the data measured by an PCN-egress-node (i.e., Deaggregator). Karagiannis, et al. Expires April 12, 2013 [Page 17] Internet-Draft Aggregated RSVP over PCN October 2012 o) As described in [RFC6661], [RFC6663], PCN reports from the PCN-egress-node (Deaggregator) to the decision point may contain flow identifiers for individual flows within an ingress-egress-aggregate that have recently experienced excess-marking. Hence, the PCN report messages used by the PCN CL edge behavior MUST be capable of carrying sequences of octet strings constituting such identifiers. When the PCN CL edge behavior is used, the individual flow identifiers need to be included in specific PCN objects, see Section 4.1 (C-Type = RSVP-AGGREGATE-IPv4-PCN-CL-FLIDs, = RSVP-AGGREGATE-IPv6-PCN-CL-FLIDs) 4.1 PCN object The PCN object reports data measured by an PCN-egress-node. PCN objects are defined for different PCN edge behavior drafts. This document defines several types of PCN objects. o) Single Marking (SM) PCN object, when IPv4 addresses are used: Class = PCN C-Type = RSVP-AGGREGATE-IPv4-PCN-SM +-------------+-------------+-------------+-------------+ | IPv4 PCN-ingress-node Address (4 bytes) | +-------------+-------------+-------------+-------------+ | IPv4 PCN-egress-node Address (4 bytes) | +-------------+-------------+-------------+-------------+ | rate of not marked PCN-traffic (NM-rate) | +-------------+-------------+-------------+-------------+ | rate of PCN-marked PCN-traffic (PM-rate) | +-------------+-------------+-------------+-------------+ Karagiannis, et al. Expires April 12, 2013 [Page 18] Internet-Draft Aggregated RSVP over PCN October 2012 o) Single Marking (SM) PCN object, when IPv6 addresses are used: Class = PCN C-Type = RSVP-AGGREGATE-IPv6-PCN-SM +-------------+-------------+-------------+-------------+ | | + + | | + IPv6 PCN-ingress-node Address (16 bytes) + | | + + | | +-------------+-------------+-------------+-------------+ | | + + | | + IPv6 PCN-egress-node Address (16 bytes) + | | + + | | +-------------+-------------+-------------+-------------+ | rate of not marked PCN-traffic (NM-rate) | +-------------+-------------+-------------+-------------+ | rate of PCN-marked PCN-traffic (PM-rate) | +-------------+-------------+-------------+-------------+ o) Controlled (CL) PCN object, IPv4 addresses are used: Class = PCN C-Type = RSVP-AGGREGATE-IPv4-PCN-CL +-------------+-------------+-------------+-------------+ | IPv4 PCN-ingress-node Address (4 bytes) | +-------------+-------------+-------------+-------------+ | IPv4 PCN-egress-node Address (4 bytes) | +-------------+-------------+-------------+-------------+ | rate of not marked PCN-traffic (NM-rate) | +-------------+-------------+-------------+-------------+ | rate of threshold-marked PCN-traffic (ThM-rate) | +-------------+-------------+-------------+-------------+ | rate of excess-traffic-marked PCN-traffic (ETM-rate) | +-------------+-------------+-------------+-------------+ Karagiannis, et al. Expires April 12, 2013 [Page 19] Internet-Draft Aggregated RSVP over PCN October 2012 o) Controlled (CL) PCN object, IPv6 addresses are used: Class = PCN C-Type = RSVP-AGGREGATE-IPv6-PCN-CL +-------------+-------------+-------------+-------------+ | | + + | | + IPv6 PCN-ingress-node Address (16 bytes) + | | + + | | +-------------+-------------+-------------+-------------+ | | + + | | + IPv6 PCN-egress-node Address (16 bytes) + | | + + | | +-------------+-------------+-------------+-------------+ | rate of not marked PCN-traffic (NM-rate) | +-------------+-------------+-------------+-------------+ | rate of threshold-marked PCN-traffic (ThM-rate) | +-------------+-------------+-------------+-------------+ | rate of excess-traffic-marked PCN-traffic (ETM-rate) | +-------------+-------------+-------------+-------------+ The fields carried by the PCN object are specified in [RFC6663], [RFC6661] and [RFC6662]: o the IPv4 or IPv6 address of the PCN-ingress-node and the IPv4 or IPv6 address of the PCN-egress-node; together they specify the ingress-egress-aggregate to which the report refers; o rate of not-marked PCN-traffic (NM-rate) in octets/second; its format is a 32-bit IEEE floating point number; o rate of PCN-marked traffic (PM-rate) in octets/second; its format is a 32-bit IEEE floating point number; o rate of threshold-marked PCN traffic (ThM-rate) in octets/second; its format is a 32-bit IEEE floating point number; o rate of excess-traffic-marked traffic (ETM-rate) in octets/second; its format is a 32-bit IEEE floating point number; Karagiannis, et al. Expires April 12, 2013 [Page 20] Internet-Draft Aggregated RSVP over PCN October 2012 o) Controlled (CL) PCN CL Flow IDs object, IPv4 addresses are used: Class = PCN C-Type = RSVP-AGGREGATE-IPv4-PCN-CL-FLIDs 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+ | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // + + | Source Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ o) Length (1 byte): the length of the RSVP-AGGREGATE-IPv4-PCN-CL-FLIDs object in units of 16 bytes. This field is used to specify the number of IPv4 flow IDs carried by this object. Each flow ID is represented by the combination of each subsequent 5 tuple: Source address, Destination address, Source Port, Destination Port and Protocol number. If Length is 0 then the RSVP-AGGREGATE-IPv4-PCN-CL-FLIDs is empty. o) Source address (4 bytes): The IPv4 source address. o) Destination address (4 bytes): The IPv4 destination address. o) Protocol (1 byte): The IP protocol number. It refers to the true upper layer protocol carried by the packets. o) Source Port (2 bytes): contains the source port number. o) Destination Port (2 bytes): contains the destination port number. Karagiannis, et al. Expires April 12, 2013 [Page 21] Internet-Draft Aggregated RSVP over PCN October 2012 o) Controlled (CL) PCN CL Flow IDs object, IPv6 addresses are used: Class = PCN C-Type = RSVP-AGGREGATE-IPv6-PCN-CL-FLIDs 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+ | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Source Address | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Destination Address | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // + + | | | Source Address | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | Destination Address | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Port | Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ o) Length (1 byte): the length of the RSVP-AGGREGATE-IPv6-PCN-CL-FLIDs object in units of 40 bytes. This field is used to specify the number of flow IDs carried by this object. Each flow ID is represented by the combination of each subsequent 5 tuple fields: Source address, Destination address, Source Port, Destination Port and Protocol number. If Length is 0 then the RSVP-AGGREGATE-IPv6-PCN-CL-FLIDs object is empty. o) Source address (16 bytes): The IPv6 source address. o) Destination address (16 bytes): The IPv6 destination address. Karagiannis, et al. Expires April 12, 2013 [Page 22] Internet-Draft Aggregated RSVP over PCN October 2012 o) Protocol (1 byte): The IP protocol number. It refers to the true upper layer protocol carried by the packets. o) Source Port (2 bytes): contains the source port number. o) Destination Port (2 bytes): contains the destination port number. 5. Security Considerations The same security considerations specified in [RFC4860] and [RFC5559] apply also to this document. 6. IANA Considerations This document makes the following requests to the IANA: o allocate a new Object Class (PCN Object), see Section 4.1. o allocate a "PCN-domain rejects e2e reservation" Error Code that may appear only in e2e PathErr messages, see Section 3.1. 7. Acknowledgments We would like to thank the authors of [draft-lefaucheur-rsvp-ecn- 01.txt], since some ideas used in this document are based on the work initiated in [draft-lefaucheur-rsvp-ecn-01.txt]. Moreover, we would like to thank Tom Taylor, Philip Eardley, Michael Menth, Toby Moncaster, Francois Le Faucheur and James Polk for the provided comments. 8. Normative References [RFC6661] T. Taylor, A, Charny, F. Huang, G. Karagiannis, M. Menth, "PCN Boundary Node Behaviour for the Controlled Load (CL) Mode of Operation", July 2012. [RFC6662] A. Charny, J. Zhang, G. Karagiannis, M. Menth, T. Taylor, "PCN Boundary Node Behaviour for the Single Marking (SM) Mode of Operation", July 2012. [RFC6663] G. Karagiannis, T. Taylor, K. Chan, M. Menth, P. Eardley, " Requirements for Signaling of (Pre-) Congestion Information in a DiffServ Domain", July 2012. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2205] Braden, R., ed., et al., "Resource ReSerVation Protocol (RSVP)- Functional Specification", RFC 2205, September 1997. Karagiannis, et al. Expires April 12, 2013 [Page 23] Internet-Draft Aggregated RSVP over PCN October 2012 [RFC3140] Black, D., Brim, S., Carpenter, B., and F. Le Faucheur, "Per Hop Behavior Identification Codes", RFC 3140, June 2001. [RFC3175] Baker, F., Iturralde, C., Le Faucheur, F., and B. Davie, "Aggregation of RSVP for IPv4 and IPv6 Reservations", RFC 3175, September 2001. [RFC4495] Polk, J. and S. Dhesikan, "A Resource Reservation Protocol (RSVP) Extension for the Reduction of Bandwidth of a Reservation Flow", RFC 4495, May 2006. [RFC4860] F. Le Faucheur, B. Davie, P. Bose, C. Christou, M. Davenport, "Generic Aggregate Resource ReSerVation Protocol (RSVP) Reservations", RFC4860, May 2007. [RFC5670] Eardley, P., "Metering and Marking Behaviour of PCN-Nodes", RFC 5670, November 2009. [RFC6660] Moncaster, T., Briscoe, B., and M. Menth, "Baseline Encoding and Transport of Pre-Congestion Information", RFC 6660, July 2012. 9. Informative References [draft-lefaucheur-rsvp-ecn-01.txt] Le Faucheur, F., Charny, A., Briscoe, B., Eardley, P., Chan, K., and J. Babiarz, "RSVP Extensions for Admission Control over Diffserv using Pre-congestion Notification (PCN) (Work in progress)", June 2006. [RFC1633] Braden, R., Clark, D., and S. Shenker, "Integrated Services in the Internet Architecture: an Overview", RFC 1633, June 1994. [RFC2211] J. Wroclawski, Specification of the Controlled-Load Network Element Service, September 1997 [RFC2212] S. Shenker et al., Specification of Guaranteed Quality of Service, September 1997 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474, December 1998. [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z. and W. Weiss, "A framework for Differentiated Services", RFC 2475, December 1998. [RFC2998] Bernet, Y., Yavatkar, R., Ford, P., Baker, F., Zhang, L., Speer, M., Braden, R., Davie, B., Wroclawski, J. and E. Felstaine, "A Framework for Integrated Services Operation Over DiffServ Networks", RFC 2998, November 2000. Karagiannis, et al. Expires April 12, 2013 [Page 24] Internet-Draft Aggregated RSVP over PCN October 2012 [RFC5559] Eardley, P., "Pre-Congestion Notification (PCN) Architecture", RFC 5559, June 2009. [SIG-NESTED] Baker, F. and P. Bose, "QoS Signaling in a Nested Virtual Private Network", Work in Progress, February 2007. 10. Authors' Address Georgios Karagiannis University of Twente P.O. Box 217 7500 AE Enschede, The Netherlands EMail: g.karagiannis@utwente.nl Anurag Bhargava Cisco Systems, Inc. 7100-9 Kit Creek Road PO Box 14987 RESEARCH TRIANGLE PARK, NORTH CAROLINA 27709-4987 USA Email: anuragb@cisco.com Karagiannis, et al. Expires April 12, 2013 [Page 25]