IETF Internet Draft NSIS Working Group J. Ash Internet Draft M. Dolly Intended Status: Informational C. Dvorak <draft-ietf-nsis-y1541-qosm-04.txt> A. Morton Expiration Date: October 2007 P. Tarapore AT&T Y. El Mghazli Alcatel-Lucent April 2007 Y.1541-QOSM -- Y.1541 QoS Model for Networks Using Y.1541 QoS Classes Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on October 2, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This draft describes a QoS-NSLP QoS model (QOSM) based on ITU-T Recommendation Y.1541 QoS signaling requirements. Y.1541 specifies 8 standard QoS classes, and the Y.1541-QOSM extensions include additional QSPEC parameters and QOSM processing guidelines. Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 1]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Summary of ITU-T Recommendations Y.1541 & Signaling Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1 Y.1541 QoS Classes . . . . . . . . . . . . . . . . . . . . 3 2.2. Y.1541-QOSM Processing Requirements . . . . . . . . . . . 4 3. Additional QSPEC Parameters for Y.1541 QOSM . . . . . . . . . 5 3.1 Traffic Model (TMOD) Extension Parameter . . . . . . . . . 5 3.2 Restoration Priority Parameter . . . . . . . . . . . . . . 5 4. Y.1541-QOSM Processing Example . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 8. Normative References . . . . . . . . . . . . . . . . . . . . . 9 9. Informative References . . . . . . . . . . . . . . . . . . . . 9 10. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 9 Conventions Used in This Document 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]. 1. Introduction This draft describes a QoS model (QOSM) for NSIS QoS signaling layer protocol (QoS-NSLP) application based on ITU-T Recommendation Y.1541 QoS signaling requirements. Y.1541 currently specifies 8 standard QoS classes, and the Y.1541-QOSM extensions include additional QSPEC parameters and QOSM processing guidelines. The extensions are based on standardization work in the ITU-T on QoS signaling requirements [Y.1541, TRQ-QoS-SIG, E.361]. [QoS-SIG] defines message types and control information for the QoS-NSLP generic to all QOSMs. A QOSM is a defined mechanism for achieving QoS as a whole. The specification of a QOSM includes a description of its QSPEC parameter information, as well as how that information should be treated or interpreted in the network. The QSPEC [QSPEC] contains a set of parameters and values describing the requested resources. It is opaque to the QoS-NSLP and similar in purpose to the TSpec, RSpec and AdSpec specified in [RFC2205, RFC2210]. The QSPEC object contains the QoS parameters defined by the QOSM. A QOSM provides a specific set of parameters to be carried in the QSPEC. At each QoS NSIS element (QNE), the QSPEC contents are interpreted by the resource management function (RMF) for purposes of policy control and traffic control, including admission control and configuration of the scheduler. Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 2]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 2. Summary of ITU-T Recommendations Y.1541 & Signaling Requirements As stated above, [Y.1541] is a specification of standardized QoS classes for IP networks (a summary of these classes is given below). [TRQ-QoS-SIG] specifies the requirements for achieving end-to-end QoS in IP networks, with Y.1541 QoS classes as a basis. [Y.1541] recommends a flexible allocation of the end-to-end performance objectives (e.g., delay) across networks, rather than a fixed per-network allocation. NSIS protocols already address most of the requirements, this document identifies additional QSPEC parameters and processing requirements needed to support the Y.1541 QOSM. 2.1 Y.1541 QoS Classes [Y.1541] proposes grouping services into QoS classes defined according to the desired QoS performance objectives. These QoS classes support a wide range of user applications. The classes group objectives for one-way IP packet delay, IP packet delay variation, IP packet loss ratio, etc. Classes 0 and 1, which generally correspond to the DiffServ EF PHB, support interactive real-time applications. Classes 2, 3, and 4, which generally correspond to the DiffServ AFxy PHB Group, support non-interactive applications. Class 5, which generally corresponds to the DiffServ best-effort PHB, has all the QoS parameters unspecified. Classes 6 and 7 provide support for extremely loss-sensitive user applications, such as high quality digital television, TDM circuit emulation, and high capacity transfers using TCP. These classes serve as a basis for agreements between end-users and service providers, and between service providers. They support a wide range of traffic applications including point-to-point telephony, data transfer, multimedia conferencing, and others. The limited number of classes supports the requirement for feasible implementation, particularly with respect to scale in global networks. The QoS classes apply to a packet flow, where [Y.1541] defines a packet flow as the traffic associated with a given connection or connectionless stream having the same source host, destination host, class of service, and session identification. The characteristics of each Y.1451 QoS class are summarized here: Class 0: Real-time, highly interactive applications, sensitive to jitter. Mean delay upper bound is 100 ms, delay variation is less than 50 ms, and loss ratio is less than 10^-3. Application examples include VoIP, Video Teleconference. Class 1: Real-time, interactive applications, sensitive to jitter. Mean delay upper bound is 400 ms, delay variation is less than 50 ms, and loss ratio is less than 10^-3. Application examples include VoIP, video teleconference. Class 2: Highly interactive transaction data. Mean delay upper bound Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 3]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 is 100 ms, delay variation is unspecified, and loss ratio is less Than 10^-3. Application examples include signaling. Class 3: Interactive transaction data. Mean delay upper bound is 400 ms, delay variation is unspecified, and loss ratio is less than 10^-3. Application examples include signaling. Class 4: Low Loss Only applications. Mean delay upper bound is 1s, delay variation is unspecified, and loss ratio is less than 10^-3. Application examples include short transactions, bulk data, video streaming Class 5: Unspecified applications with unspecified mean delay, delay variation, and loss ratio. Application examples include traditional applications of Default IP Networks Class 6: Mean delay <= 100 ms, delay variation <= 50 ms, loss ratio <= 10^-5. Applications that are highly sensitive to loss, such as television transport, high-capacity TCP transfers, and TDM circuit emulation. Class 7: Mean delay <= 400 ms, delay variation <= 50 ms, loss ratio <= 10^-5. Applications that are highly sensitive to loss, such as television transport, high-capacity TCP transfers, and TDM circuit emulation. These classes enable SLAs to be defined between customers and network service providers with respect to QoS requirements. The service provider then needs to ensure that the requirements are recognized and receive appropriate treatment across network layers. 2.2 Y.1541-QOSM Processing Requirements [TRQ-QoS-SIG] provides the requirements for signaling information regarding IP-based QoS at the interface between the user and the network (UNI) and across interfaces between different networks (NNI). To meet specific network performance requirements specified for the Y.1541 QoS classes, a network needs to provide specific user plane functionality at UNI and NNI interfaces. Dynamic network provisioning at a UNI and/or NNI node allows the ability to dynamically request a traffic contract for an IP flow from a specific source node to one or more destination nodes. In response to the request, the network determines if resources are available to satisfy the request and provision the network. It MUST be possible to derive the following service level parameters as part of the process of requesting service: a. Y.1541 QoS class b. rate (r) c. peak rate (p) Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 4]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 d. bucket size (b) e. peak bucket size (Bp) f. maximum packet size (M) g. DiffServ PHB class [RFC2475] h. admission priority i. restoration priority All parameters except Bp, M, and restoration priority have already been specified in [QSPEC]. These additional parameters are specified in Section 3. It MUST be possible to perform the following QoS-NSLP signaling functions to meet Y.1541-QOSM requirements: a. accumulate delay, delay variation and loss ratio across the end-to-end connection, which may span multiple domains b. enable negotiation of Y.1541 QoS class across domains. c. enable negotiation of delay, delay variation, and loss ratio across domains. These signaling requirements are already supported by [QoS-SIG] and the functions are illustrated in Section 4. 3. Additional QSPEC Parameters for Y.1541 QOSM 3.1 Traffic Model (TMOD) Extension Parameter The traffic model (TMOD) extension parameter is represented by one floating point number in single-precision IEEE floating point format and one 32-bit unsigned integer. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Peak Bucket Size [Bp] (32-bit IEEE floating point number) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Maximum Packet Size [M] (32-bit unsigned integer) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ When the Bp term is represented as an IEEE floating point value, the sign bit MUST be zero (all values MUST be non-negative). Exponents less than 127 (i.e., 0) are prohibited. Exponents greater than 162 (i.e., positive 35) are discouraged, except for specifying a peak rate of infinity. Infinity is represented with an exponent of all ones (255) and a sign bit and mantissa of all zeroes. The maximum packet size (M) is an unsigned integer. 3.2 Restoration Priority Parameter Restoration priority is the urgency with which a service requires successful restoration under failure conditions. Restoration Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 5]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 priority is achieved by provisioning sufficient backup capacity, as necessary, and allowing relative priority for access to available bandwidth when there is contention for restoration bandwidth. Restoration priority is defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Rest. Priority| (Reserved) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Restoration Priority: 3 priority values are listed here in the order of lowest priority to highest priority: 0 - best effort 1 - normal 2 - high Each restoration priority class has two parameters: a. Time-to-Restore: Total amount of time to restore traffic streams belonging to a given restoration class impacted by the failure. This time period depends on the technology deployed for restoration. A fast recovery period of < 200 ms is based on current experience with SONET rings and a slower recovery period of 2 seconds is suggested in order to enable a voice call to recover without being dropped. Accordingly, candidate restoration objectives are: High Restoration Priority: Time-to-Restore <= 200 ms Normal Restoration Priority: Time-to-Restore <= 2 s. Best Effort Restoration Priority: Time-to-Restore = Unspecified b. Extent of Restoration: Percentage of traffic belonging to the restoration class that can be restored. This percentage depends on the amount of spare capacity engineered. All high priority restoration priority traffic, for example, may be "guaranteed" at 100% by the service provider. Other classes may offer lesser chances for successful restoration. The restoration extent for these lower priority classes depend on SLA agreements developed between the service provider and the customer. 4. Y.1541-QOSM Processing Example In this Section we illustrate the operation of the Y.1541 QOSM, and show how current QoS-NSLP and QSPEC functionality is used. No new processing capabilities or parameters are required to enable the Y.1541 QOSM. As described in the example given in [QSPEC] (Section 4.4) and as illustrated in Figure 1, the QoS NSIS initiator (QNI) initiates an Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 6]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 end-to-end, inter-domain QoS NSLP RESERVE message containing the Initiator QSPEC. In the case of the Y.1541 QOSM, the Initiator QSPEC specifies the <Y.1541 QOS Class>, <TMOD>, <TMOD Extension>, <Admission Priority>, <Restoration Priority>, and perhaps other QSPEC parameters for the flow. As described in Section 3, the TMOD extension parameter contains the optional, Y.1541-QOSM-specific parameters Bp and M; restoration priority is also an optional, Y.1541-QOSM-specific parameter. As illustrated in Figure 1, the RESERVE message may cross multiple domains supporting different QOSMs. In this illustration, the initiator QSPEC arrives in an QoS NSLP RESERVE message at the ingress node of the local-QOSM domain. As described in [QoS-SIG] and [QSPEC], at the ingress edge node of the local-QOSM domain, the end-to-end, inter-domain QoS-NSLP message may trigger the generation of a local QSPEC, and the initiator QSPEC encapsulated within the messages signaled through the local domain. The local QSPEC is used for QoS processing in the local-QOSM domain, and the Initiator QSPEC is used for QoS processing outside the local domain. As specified in [QSPEC], if any QNE cannot meet the requirements designated by the initiator QSPEC to support an optional QSPEC parameter, with the M bit set to zero for the parameter, for example, it cannot support the accumulation of end-to-end delay with the <Path Latency> parameter, the QNE sets the N flag (not supported flag) for the path latency parameter to one. Also, the Y.1541-QOSM requires negotiation of the <Y.1541 QoS Class> across domains. This negotiation can be done with the use of the existing procedures already defined in [QoS-SIG]. For example, the QNI sets <Desired QoS>, <Minimum QoS>, <Available QoS> objects to include <Y.1541 QoS Class>, <Path Latency>, <Path Jitter>, <Path BER> parameters. The QNE/domain SHOULD set the Y.1541 class and cumulative parameters, e.g., <Path Latency>, that can be achieved in the <QoS Available> object (but not less than specified in <Minimum QoS>). This could include, for example, setting the <Y.1541 QoS Class> to a lower class than specified in <QoS Desired> (but not lower than specified in <Minimum QoS>). If the <Available QoS> fails to satisfy one or more of the <Minimum QoS> objectives, the QNE/domain notifies the QNI and the reservation is aborted. Otherwise, the QNR notifies the QNI of the <QoS Available> for the reservation. When the available <Y.1541 QoS Class> must be reduced from the desired <Y.1541 QoS Class>, say because the delay objective has been exceeded, then there is an incentive to respond with an available value for delay in the <Path Latency> parameter. If the available <Path Latency> is 150 ms (still useful for many applications) and the desired QoS is Class 0 (with its 100 ms objective), then the response would be that Class 0 cannot be achieved and Class 1 is available (with its 400 ms objective). In addition, this QOSM allows the response to include an available Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 7]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 <Path Latency> = 150 ms, making acceptance of the available <Y.1541 QoS Class> more likely. There are many long paths where the propagation delay alone exceeds the Y.1541 Class 0 objective, so this feature adds flexibility to commit to exceed the Class 1 objective when possible. This example illustrates Y.1541-QOSM negotiation of <Y.1541 QoS Class> and cumulative parameter values that can be achieve end-to-end. The example illustrates how the QNI can use the cumulative values collected in <QoS Available> to decide if a lower <Y.1541 QoS Class> than specified in <QoS Desired> is acceptable. |------| |------| |------| |------| | e2e |<->| e2e |<------------------------->| e2e |<->| e2e | | QOSM | | QOSM | | QOSM | | QOSM | | | |------| |-------| |-------| |------| | | | NSLP | | NSLP |<->| NSLP |<->| NSLP |<->| NSLP | | NSLP | |Y.1541| |local | |local | |local | |local | |Y.1541| | QOSM | | QOSM | | QOSM | | QOSM | | QOSM | | QOSM | |------| |------| |-------| |-------| |------| |------| ----------------------------------------------------------------- |------| |------| |-------| |-------| |------| |------| | NTLP |<->| NTLP |<->| NTLP |<->| NTLP |<->| NTLP |<->| NTLP | |------| |------| |-------| |-------| |------| |------| QNI QNE QNE QNE QNE QNR (End) (Ingress Edge) (Interior) (Interior) (Egress Edge) (End) Figure 1 Example of Y.1541-QOSM Operation 5. Security Considerations The security considerations of [QoS-SIG] and [QSPEC] apply to this Document. There are no new security considerations based on this document. 6. IANA Considerations This section defines the registries and initial codepoint assignments for the QSPEC template, in accordance with BCP 26 RFC 2434 [RFC2434]. It also defines the procedural requirements to be followed by IANA in allocating new codepoints. This document specifies the following QSPEC parameters to be assigned within the QSPEC Parameter ID registry created in [QSPEC]: <TMOD Extension> parameter (Section 3.1) <Restoration Priority> parameter (Section 3.2) This specification creates the following registry with the structure as defined below: Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 8]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 Restoration Priority Parameter (8 bits): The following values are allocated by this specification: 0-2: assigned as specified in Section 3.2: Restoration Priority 0: best-effort priority 1: normal priority 2: high priority The allocation policies for further values are as follows: 3-63: Standards Action 64-255: Reserved 7. Acknowledgements The authors thank Attila Bader, Cornelia Kappler, and Sven Van den Bosch for helpful comments and discussion. 8. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [QoS-SIG] Van den Bosch, S., et. al., "NSLP for Quality-of-Service Signaling," work in progress. [QSPEC], Ash, J., et. al., "QoS-NSLP QSPEC Template," work in progress. [TRQ-QoS-SIG] ITU-T Recommendation, "Signaling Requirements for IP-QoS," January 2004. [Y.1541] ITU-T Recommendation Y.1541, "Network Performance Objectives for IP-Based Services," February 2006. 9. Informative References [E.361] ITU-T Recommendation, "QoS Routing Support for Interworking of QoS Service Classes Across Routing Technologies," May 2003. [RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated Services," RFC 2210, September 1997. [RFC2434] Narten, T., Alvestrand, H., "Guidelines for Writing an IANA Considerations Section in RFCs," RFC 2434, October 1998. [RFC2475] Blake, S., et. al., "An Architecture for Differentiated Services", RFC 2475, December 1998. 10. Authors' Addresses Jerry Ash AT&T Room MT D5-2A01 200 Laurel Avenue Middletown, NJ 07748, USA Phone: +1-(732)-420-4578 Email: gash@att.com Martin Dolly AT&T Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 9]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 Room E3-3A14 200 S. Laurel Avenue Middletown, NJ 07748 Phone: + 1 732 420-4574 E-mail: mdolly@att.com Chuck Dvorak AT&T Room 2A37 180 Park Avenue, Building 2 Florham Park, NJ 07932 Phone: + 1 973-236-6700 E-mail: cdvorak@att.com Yacine El Mghazli Alcatel-Lucent Route de Nozay 91460 Marcoussis cedex - FRANCE Phone: +33 1 69 63 41 87 Email: yacine.el_mghazli@alcatel.fr Al Morton AT&T Room D3-3C06 200 S. Laurel Avenue Middletown, NJ 07748 Phone: + 1 732 420-1571 E-mail: acmorton@att.com Percy Tarapore AT&T Room D1-33 200 S. Laurel Avenue Middletown, NJ 07748 Phone: + 1 732 420-4172 E-mail: tarapore@.att.com Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 10]
Internet Draft Y.1541-QOSM for Y.1541 QoS Classes April 2007 such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Ash, et. al. <draft-ietf-nsis-y1541-qosm-04.txt> [Page 11]
