PCE Working Group D. Dhody Internet-Draft Huawei Technologies India Pvt Intended status: Standards Track Ltd Expires: September 27, 2013 V. Manral Hewlett-Packard Corp. Z. Ali G. Swallow Cisco Systems K. Kumaki KDDI Corporation March 26, 2013 Extensions to the Path Computation Element Communication Protocol (PCEP) to compute service aware Label Switched Path (LSP). draft-ietf-pce-pcep-service-aware-00 Abstract In certain networks like financial information network (stock/ commodity trading) and enterprises using cloud based applications, Latency (delay), Latency-Variation (jitter) and Packet loss is becoming a key requirement for path computation along with other constraints and metrics. Latency, Latency-Variation and Packet Loss is associated with the Service Level Agreement (SLA) between customers and service providers. [MPLS-DELAY-FWK] describes MPLS architecture to allow Latency (delay), Latency-Variation (jitter) and Packet loss as properties. [OSPF-TE-EXPRESS] and [ISIS-TE-EXPRESS] describes mechanisms with which network performance information is distributed via OSPF and ISIS respectively. This document describes the extension to PCEP to carry Latency, Latency-Variation and Loss as constraints for end to end path computation. 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 Dhody, et al. Expires September 27, 2013 [Page 1] Internet-Draft SERVICE-AWARE March 2013 material or to cite them other than as "work in progress." This Internet-Draft will expire on September 27, 2013. Copyright Notice Copyright (c) 2013 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. Dhody, et al. Expires September 27, 2013 [Page 2] Internet-Draft SERVICE-AWARE March 2013 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. PCEP Requirements . . . . . . . . . . . . . . . . . . . . . . 5 4. PCEP extensions . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. Latency (Delay) Metric . . . . . . . . . . . . . . . . . . 6 4.1.1. Latency (Delay) Metric Value . . . . . . . . . . . . . 6 4.2. Latency Variation (Jitter) Metric . . . . . . . . . . . . 7 4.2.1. Latency Variation (Jitter) Metric Value . . . . . . . 7 4.3. Packet Loss Metric . . . . . . . . . . . . . . . . . . . . 8 4.3.1. Packet Loss Metric Value . . . . . . . . . . . . . . . 9 4.4. Non-Understanding / Non-Support of Service Aware Path Computation . . . . . . . . . . . . . . . . . . . . . . . 9 4.5. Mode of Operation . . . . . . . . . . . . . . . . . . . . 9 4.5.1. Examples . . . . . . . . . . . . . . . . . . . . . . . 10 5. Relationship with Objective function . . . . . . . . . . . . . 11 6. Protocol Consideration . . . . . . . . . . . . . . . . . . . . 11 6.1. Inter domain Consideration . . . . . . . . . . . . . . . . 11 6.1.1. Inter-AS Link . . . . . . . . . . . . . . . . . . . . 12 6.1.2. Inter-Layer Consideration . . . . . . . . . . . . . . 12 6.2. Reoptimization Consideration . . . . . . . . . . . . . . . 12 6.3. Point-to-Multipoint (P2MP) . . . . . . . . . . . . . . . . 12 6.3.1. P2MP Latency Metric . . . . . . . . . . . . . . . . . 12 6.3.2. P2MP Latency Variation Metric . . . . . . . . . . . . 13 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 8. Security Considerations . . . . . . . . . . . . . . . . . . . 13 9. Manageability Considerations . . . . . . . . . . . . . . . . . 14 9.1. Control of Function and Policy . . . . . . . . . . . . . . 14 9.2. Information and Data Models . . . . . . . . . . . . . . . 14 9.3. Liveness Detection and Monitoring . . . . . . . . . . . . 14 9.4. Verify Correct Operations . . . . . . . . . . . . . . . . 14 9.5. Requirements On Other Protocols . . . . . . . . . . . . . 14 9.6. Impact On Network Operations . . . . . . . . . . . . . . . 14 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 11.1. Normative References . . . . . . . . . . . . . . . . . . . 15 11.2. Informative References . . . . . . . . . . . . . . . . . . 15 Appendix A. Contributor Addresses . . . . . . . . . . . . . . . . 16 Dhody, et al. Expires September 27, 2013 [Page 3] Internet-Draft SERVICE-AWARE March 2013 1. Introduction Real time Network Performance is becoming a critical in the path computation in some networks. There exist mechanism described in [RFC6374] to measure latency, latency-Variation and packet loss after the LSP has been established, which is inefficient. It is important that latency, latency-variation and packet loss are considered during path selection process, even before the LSP is setup. TED is populated with network performance information like link latency, latency variation and packet loss through [OSPF-TE-EXPRESS] or [ISIS-TE-EXPRESS]. Path Computation Client (PCC) can request Path Computation Element (PCE) to provide a path meeting end to end network performance criteria. This document extends Path Computation Element Communication Protocol (PCEP) [RFC5440] to handle network performance constraint. PCE MAY use mechanism described in [MPLS-TE-EXPRESS-PATH] on how to use the link latency, latency variation and packet loss information for end to end path selection. 1.1. 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 [RFC2119]. 2. Terminology The following terminology is used in this document. IGP: Interior Gateway Protocol. Either of the two routing protocols, Open Shortest Path First (OSPF) or Intermediate System to Intermediate System (IS-IS). IS-IS: Intermediate System to Intermediate System. OSPF: Open Shortest Path First. PCC: Path Computation Client: any client application requesting a path computation to be performed by a Path Computation Element. PCE: Path Computation Element. An entity (component, application, or network node) that is capable of computing a network path or route based on a network graph and applying computational constraints. Dhody, et al. Expires September 27, 2013 [Page 4] Internet-Draft SERVICE-AWARE March 2013 TE: Traffic Engineering. 3. PCEP Requirements End-to-end service optimization based on latency, latency-variation and packet loss is a key requirement for service provider. Following key requirements associated with latency, latency-variation and loss are identified for PCEP: 1. Path Computation Element (PCE) supporting this draft MUST have the capability to compute end-to-end path with latency, latency- variation and packet loss constraints. It MUST also support the combination of network performance constraint (latency, latency- variation, loss...) with existing constraints (cost, hop- limit...) 2. Path Computation Client (PCC) MUST be able to request for network performance constraint in path request message as the key constraint to be optimized or to suggest boundary condition that should not be crossed. 3. PCEs are not required to support service aware path computation. Therefore, it MUST be possible for a PCE to reject a Path Computation Request message with a reason code that indicates no support for service-aware path computation. 4. PCEP SHOULD provide a means to return end to end network performance information of the computed path in the reply message. 5. PCEP SHOULD provide mechanism to compute multi-domain (e.g., Inter-AS, Inter-Area or Multi-Layer) service aware paths. It is assumed that such constraints are only meaningful if used consistently: for instance, if the delay of a computed path segment is exchanged between two PCEs residing in different domains, consistent ways of defining the delay must be used. 4. PCEP extensions This section defines PCEP extensions (see [RFC5440]) for requirements outlined in Section 3. The proposed solution is used to support network performance and service aware path computation. This document defines the following optional types for the METRIC object defined in [RFC5440]. For explanation of these metrics, the following terminology is used Dhody, et al. Expires September 27, 2013 [Page 5] Internet-Draft SERVICE-AWARE March 2013 and expanded along the way. - A network comprises of a set of N links {Li, (i=1...N)}. - A path P of a P2P LSP is a list of K links {Lpi,(i=1...K)}. 4.1. Latency (Delay) Metric Link delay metric is defined in [OSPF-TE-EXPRESS] and [ISIS-TE- EXPRESS]. P2P latency metric type of METRIC object in PCEP encodes the sum of the link delay metric of all links along a P2P Path. Specifically, extending on the above mentioned terminology: - A Link delay metric of link L is denoted D(L). - A P2P latency metric for the Path P = Sum {D(Lpi), (i=1...K)}. * T=13(IANA): Latency metric PCC MAY use this latency metric In PCReq to request a path meeting the end to end latency requirement. In this case B bit MUST be set to suggest a bound (a maximum) for the path latency metric that must not be exceeded for the PCC to consider the computed path as acceptable. The path metric must be less than or equal to the value specified in the metric-value field. PCC MAY also use this metric to ask PCE to optimize delay during path computation, in this case B flag will be cleared. PCE MAY use this latency metric In PCRep along with NO-PATH object incase PCE cannot compute a path meeting this constraint. PCE MAY also use this metric to reply the computed end to end latency metric to PCC. 4.1.1. Latency (Delay) Metric Value [OSPF-TE-EXPRESS] and [ISIS-TE-EXPRESS] defines "Unidirectional Link Delay Sub-TLV" in a 24-bit field. [RFC5440] defines the METRIC object with 32-bit metric value. Consequently, encoding for Latency (Delay) Metric Value is defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Latency (Delay) Metric | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Reserved (8 bits): Reserved field. This field MUST be set to zero on Dhody, et al. Expires September 27, 2013 [Page 6] Internet-Draft SERVICE-AWARE March 2013 transmission and MUST be ignored on receipt. Latency (Delay) Metric (24 bits): Represents the end to end Latency (delay) quantified in units of microseconds and MUST be encoded as integer value. With the maximum value 16,777,215 representing 16.777215 sec. 4.2. Latency Variation (Jitter) Metric Link delay variation metric is defined in [OSPF-TE-EXPRESS] and [ISIS-TE-EXPRESS]. P2P latency variation metric type of METRIC object in PCEP encodes a function of the link delay variation metric of all links along a P2P Path. Specifically, extending on the above mentioned terminology: - A Latency variation of link L is denoted DV(L). - A P2P latency variation metric for the Path P = function {DV(Lpi), (i=1...K)}. Specification of the "Function" used to drive latency variation metric of a path from latency variation metrics of individual links along the path is beyond the scope of this document. * T=14(IANA): Latency Variation metric PCC MAY use this latency variation metric In PCReq to request a path meeting the end to end latency variation requirement. In this case B bit MUST be set to suggest a bound (a maximum) for the path latency variation metric that must not be exceeded for the PCC to consider the computed path as acceptable. The path metric must be less than or equal to the value specified in the metric-value field. PCC MAY also use this metric to ask PCE to optimize jitter during path computation, in this case B flag will be cleared. PCE MAY use this latency variation metric In PCRep along with NO-PATH object incase PCE cannot compute a path meeting this constraint. PCE MAY also use this metric to reply the computed end to end latency variation metric to PCC. 4.2.1. Latency Variation (Jitter) Metric Value [OSPF-TE-EXPRESS] and [ISIS-TE-EXPRESS] defines "Unidirectional Delay Variation Sub-TLV" in a 24-bit field. [RFC5440] defines the METRIC object with 32-bit metric value. Consequently, encoding for Latency Variation (Jitter) Metric Value is defined as follows: Dhody, et al. Expires September 27, 2013 [Page 7] Internet-Draft SERVICE-AWARE March 2013 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Latency variation (jitter) Metric | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Reserved (8 bits): Reserved field. This field MUST be set to zero on transmission and MUST be ignored on receipt. Latency variation (jitter) Metric (24 bits): Represents the end to end Latency variation (jitter) quantified in units of microseconds and MUST be encoded as integer value. With the maximum value 16,777,215 representing 16.777215 sec. 4.3. Packet Loss Metric [OSPF-TE-EXPRESS] and [ISIS-TE-EXPRESS] defines "Unidirectional Link Loss". Packet Loss Metric metric type of METRIC object in PCEP encodes a function of the link's unidirectional loss metric of all links along a P2P Path. Specifically, extending on the above mentioned terminology: The end to end Packet Loss for the path is represented by this metric. - A Packet loss of link L is denoted PL(L). - A P2P packet loss metric for the Path P = function {PL(Lpi), (i=1...K)}. Specification of the "Function" used to drive end to end packet loss metric of a path from packet loss metrics of individual links along the path is beyond the scope of this document. * T=15(IANA): Packet Loss metric PCC MAY use this packet loss metric In PCReq to request a path meeting the end to end packet loss requirement. In this case B bit MUST be set to suggest a bound (a maximum) for the path packet loss metric that must not be exceeded for the PCC to consider the computed path as acceptable. The path metric must be less than or equal to the value specified in the metric-value field. PCC MAY also use this metric to ask PCE to optimize packet loss during path computation, in this case B flag will be cleared. PCE MAY use this packet loss metric In PCRep along with NO-PATH object incase PCE cannot compute a path meeting this constraint. PCE Dhody, et al. Expires September 27, 2013 [Page 8] Internet-Draft SERVICE-AWARE March 2013 MAY also use this metric to reply the computed end to end packet loss metric to PCC. 4.3.1. Packet Loss Metric Value [OSPF-TE-EXPRESS] and [ISIS-TE-EXPRESS] defines "Unidirectional Link Loss Sub-TLV" in a 24-bit field. [RFC5440] defines the METRIC object with 32-bit metric value. Consequently, encoding for Packet Loss Metric Value is defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Packet loss Metric | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Reserved (8 bits): Reserved field. This field MUST be set to zero on transmission and MUST be ignored on receipt. Packet loss Metric (24 bits): Represents the end to end packet loss quantified as a percentage of packets lost and MUST be encoded as integer. The basic unit is 0.000003%, with the maximum value 16,777,215 representing 50.331645% (16,777,215 * 0.000003%). This value is the highest packet loss percentage that can be expressed. 4.4. Non-Understanding / Non-Support of Service Aware Path Computation If the P bit is clear in the object header and PCE does not understand or does not support service aware path computation it SHOULD simply ignore this METRIC. If the P Bit is set in the object header and PCE receives new METRIC type in path request and it understands the METRIC type, but the PCE is not capable of service aware path computation, the PCE MUST send a PCErr message with a PCEP-ERROR Object Error-Type = 4 (Not supported object) [RFC5440]. The path computation request MUST then be cancelled. If the PCE does not understand the new METRIC type, then the PCE MUST send a PCErr message with a PCEP-ERROR Object Error-Type = 3 (Unknown object) [RFC5440]. 4.5. Mode of Operation As explained in [RFC5440], The METRIC object is optional and can be used for several purposes. In a PCReq message, a PCC MAY insert one or more METRIC objects: Dhody, et al. Expires September 27, 2013 [Page 9] Internet-Draft SERVICE-AWARE March 2013 o To indicate the metric that MUST be optimized by the path computation algorithm (Latency, Latency-Variation or Loss) o To indicate a bound on the path METRIC (Latency, Latency-Variation or Loss) that MUST NOT be exceeded for the path to be considered as acceptable by the PCC. In a PCRep message, the METRIC object MAY be inserted so as to provide the METRIC (Latency, Latency-Variation or Loss) for the computed path. It MAY also be inserted within a PCRep with the NO- PATH object to indicate that the metric constraint could not be satisfied. The path computation algorithmic aspects used by the PCE to optimize a path with respect to a specific metric are outside the scope of this document. All the rules of processing METRIC object as explained in [RFC5440] are applicable to the new metric types as well. In a PCReq message, a PCC MAY insert more than one METRIC object to be optimized, in such a case PCE should find the path that is optimal when both the metrics are considered together. 4.5.1. Examples Example 1: If a PCC sends a path computation request to a PCE where two metric to optimize are the latency and the packet loss, two METRIC objects are inserted in the PCReq message: o First METRIC object with B=0, T=13 (TBA - IANA), C=1, metric- value=0x0000 o Second METRIC object with B=0, T=15 (TBA - IANA), C=1, metric- value=0x0000 PCE in such a case should try to optimize both the metrics and find a path with the minimum latency and packet loss, if a path can be found by the PCE and there is no policy that prevents the return of the computed metric, the PCE inserts two METRIC object with B=0, T=13 (TBA - IANA), metric-value= computed end to end latency and second METRIC object with B=1, T=15 (TBA - IANA), metric-value= computed end to end packet loss. Example 2: If a PCC sends a path computation request to a PCE where the metric to optimize is the latency and the packet loss must not exceed the value of M, two METRIC objects are inserted in the PCReq message: Dhody, et al. Expires September 27, 2013 [Page 10] Internet-Draft SERVICE-AWARE March 2013 o First METRIC object with B=0, T=13 (TBA - IANA), C=1, metric- value=0x0000 o Second METRIC object with B=1, T=15 (TBA - IANA), metric-value=M If a path satisfying the set of constraints can be found by the PCE and there is no policy that prevents the return of the computed metric, the PCE inserts one METRIC object with B=0, T=13 (TBA - IANA), metric-value= computed end to end latency. Additionally, the PCE may insert a second METRIC object with B=1, T=15 (TBA - IANA), metric-value= computed end to end packet loss. 5. Relationship with Objective function [RFC5541] defines mechanism to specify an optimization criteria, referred to as objective functions. The new metric types specified in this document can continue to use the existing Objective function. Minimum Cost Path (MCP) is one such objective function. o A network comprises a set of N links {Li, (i=1...N)}. o A path P is a list of K links {Lpi,(i=1...K)}. o Metric of link L is denoted M(L). This can be any metric, including the ones defined in this document. o The cost of a path P is denoted C(P), where C(P) = sum {M(Lpi),(i=1...K)}. Name: Minimum Cost Path (MCP) Description: Find a path P such that C(P) is minimized. The new metric types for example latency (delay) can continue to use the above objective function to find the minimum cost path where cost is latency (delay). At the same time new objective functions can be defined in future to optimize these new metric types. 6. Protocol Consideration There is no change in the message format of Path Request and Reply Message. 6.1. Inter domain Consideration [RFC5441] describes the BRPC procedure to compute end to end optimized inter domain path by cooperating PCEs. The network Dhody, et al. Expires September 27, 2013 [Page 11] Internet-Draft SERVICE-AWARE March 2013 performance constraints can be applied end to end in similar manner as IGP or TE cost. All domains should have the same understanding of the METRIC (Latency-Variation etc) for end-to-end inter-domain path computation to make sense. Otherwise some form of Metric Normalization as described in [RFC5441] MAY need to be applied. 6.1.1. Inter-AS Link The IGP in each neighbor domain can advertise its inter-domain TE link capabilities, this has been described in [RFC5316] (ISIS) and [RFC5392] (OSPF). The network performance link properties are described in [OSPF-TE-EXPRESS] and [ISIS-TE-EXPRESS], the same properties must be advertised using the mechanism described in [RFC5392] (OSPF) and [RFC5316] (ISIS). 6.1.2. Inter-Layer Consideration PCEP supporting this draft SHOULD provide mechanism to support different Metric requirements for different Layers. This is important as the network performance metric would be different for Packet and Optical (TDM, LSC etc) Layers. In order to allow different Metric-Value to be applied within different network layers, multiple METRIC objects of the same type MAY be present. In such a case, the first METRIC object specifies an metric for the higher- layer network, and subsequent METRIC objects specify objection functions of the subsequent lower-layer networks. 6.2. Reoptimization Consideration PCC can monitor the setup LSPs and incase of degradation of network performance constraints, it MAY ask PCE for reoptimization as per [RFC5440]. 6.3. Point-to-Multipoint (P2MP) This document defines the following optional types for the METRIC object defined in [RFC5440] for P2MP TE LSPs. Additional metric types for P2MP TE LSPs are to be added in a future revision 6.3.1. P2MP Latency Metric P2MP latency metric type of METRIC object in PCEP encodes the path latency metric for destination that observes the worst latency metric among all destination of the P2MP tree. Specifically, extending on the above mentioned terminology: Dhody, et al. Expires September 27, 2013 [Page 12] Internet-Draft SERVICE-AWARE March 2013 - A P2MP Tree T comprises of a set of M destinations {Dest_j, (j=1...M)} - P2P latency metric of the Path to destination Dest_j is denoted by LM(Dest_j). - P2MP latency metric for the P2MP tree T = Maximum {LM(Dest_j), (j=1...M)}. Value for P2MP latency metric is to be assigned by IANA 6.3.2. P2MP Latency Variation Metric P2MP latency variation metric type of METRIC object in PCEP encodes the path latency variation metric for destination that observes the worst latency variation metric among all destination of the P2MP tree. Specifically, extending on the above mentioned terminology: - A P2MP Tree T comprises of a set of M destinations {Dest_j, (j=1...M)} - P2P latency variation metric of the Path to destination Dest_j is denoted by LVM(Dest_j). - P2MP latency variation metric for the P2MP tree T = Maximum {LVM(Dest_j), (j=1...M)}. Value for P2MP latency variation metric is to be assigned by IANA 7. IANA Considerations IANA has defined a registry for new METRIC type. Type Meaning 13(TBD) Latency (delay) metric 14(TBD) Latency Variation (jitter) metric 15(TBD) Packet Loss metric 16(TBD) P2MP latency metric 17(TBD) P2MP latency variation metric 8. Security Considerations This document defines three new METRIC Types which does not add any new security concerns to PCEP protocol. Dhody, et al. Expires September 27, 2013 [Page 13] Internet-Draft SERVICE-AWARE March 2013 9. Manageability Considerations 9.1. Control of Function and Policy The only configurable item is the support of the new service-aware METRICS on a PCE which MAY be controlled by a policy module. If the new METRIC is not supported/allowed on a PCE, it MUST send a PCErr message as specified in Section 4.4. 9.2. Information and Data Models [PCEP-MIB] describes the PCEP MIB, there are no new MIB Objects for this document. 9.3. Liveness Detection and Monitoring Mechanisms defined in this document do not imply any new liveness detection and monitoring requirements in addition to those already listed in [RFC5440]. 9.4. Verify Correct Operations Mechanisms defined in this document do not imply any new operation verification requirements in addition to those already listed in [RFC5440]. 9.5. Requirements On Other Protocols PCE requires the TED to be populated with network performance information like link latency, latency variation and packet loss. This mechanism is described in [OSPF-TE-EXPRESS] or [ISIS-TE-EXPRESS]. 9.6. Impact On Network Operations Mechanisms defined in this document do not have any impact on network operations in addition to those already listed in [RFC5440]. 10. Acknowledgments We would like to thank Young Lee, Venugopal Reddy, Reeja Paul, Sandeep Kumar Boina, Suresh babu, Quintin Zhao and Chen Huaimo for their useful comments and suggestions. 11. References Dhody, et al. Expires September 27, 2013 [Page 14] Internet-Draft SERVICE-AWARE March 2013 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. 11.2. Informative References [RFC5441] Vasseur, JP., Zhang, R., Bitar, N., and JL. Le Roux, "A Backward-Recursive PCE-Based Computation (BRPC) Procedure to Compute Shortest Constrained Inter-Domain Traffic Engineering Label Switched Paths", RFC 5441, April 2009. [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in Support of Inter-Autonomous System (AS) MPLS and GMPLS Traffic Engineering", RFC 5316, December 2008. [RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in Support of Inter-Autonomous System (AS) MPLS and GMPLS Traffic Engineering", RFC 5392, January 2009. [RFC5541] Le Roux, JL., Vasseur, JP., and Y. Lee, "Encoding of Objective Functions in the Path Computation Element Communication Protocol (PCEP)", RFC 5541, June 2009. [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay Measurement for MPLS Networks", RFC 6374, September 2011. [MPLS-DELAY-FWK] Fu, X., Manral, V., McDysan, D., Malis, A., Giacalone, S., Betts, M., Wang, Q., and J. Drake, "Traffic Engineering architecture for services aware MPLS [draft-fuxh-mpls-delay-loss-te-framework]", Oct 2012. [OSPF-TE-EXPRESS] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. Previdi, "OSPF Traffic Engineering (TE) Metric Extensions Dhody, et al. Expires September 27, 2013 [Page 15] Internet-Draft SERVICE-AWARE March 2013 [draft-ietf-ospf-te-metric-extensions]", May 2012. [ISIS-TE-EXPRESS] Previdi, S., Giacalone, S., Ward, D., Drake, J., Atlas, A., and C. Filsfils, "IS-IS Traffic Engineering (TE) Metric Extensions [draft-previdi-isis-te-metric-extensions]", Oct 2012. [MPLS-TE-EXPRESS-PATH] Atlas, A., Drake, J., Ward, D., Giacalone, S., Previdi, S., and C. Filsfils, "Performance-based Path Selection for Explicitly Routed LSPs [draft-atlas-mpls-te-express-path]", June 2012. [PCEP-MIB] Kiran Koushik, A S., Stephan, E., Zhao, Q., King, D., and J. Hardwick, "PCE communication protocol(PCEP) Management Information Base [draft-ietf-pce-pcep-mib]", July 2012. Appendix A. Contributor Addresses Clarence Filsfils Cisco Systems EMail: cfilsfil@cisco.com Siva Sivabalan Cisco Systems EMail: msiva@cisco.com Stefano Previdi Cisco Systems EMail: sprevidi@cisco.com Udayasree Palle Huawei Technologies India Pvt Ltd Leela Palace Bangalore, Karnataka 560008 INDIA EMail: udayasree.palle@huawei.com Dhody, et al. Expires September 27, 2013 [Page 16] Internet-Draft SERVICE-AWARE March 2013 Authors' Addresses Dhruv Dhody Huawei Technologies India Pvt Ltd Leela Palace Bangalore, Karnataka 560008 INDIA EMail: dhruv.dhody@huawei.com Vishwas Manral Hewlett-Packard Corp. 191111 Pruneridge Ave. Cupertino, CA 95014 USA EMail: vishwas.manral@hp.com Zafar Ali Cisco Systems EMail: zali@cisco.com George Swallow Cisco Systems EMail: swallow@cisco.com Kenji Kumaki KDDI Corporation EMail: ke-kumaki@kddi.com Dhody, et al. Expires September 27, 2013 [Page 17]