Next Steps in Signaling C. Kappler Internet-Draft Siemens AG Expires: November 13, 2005 May 12, 2005 A QoS Model for Signaling IntServ Controlled-Load Service with NSIS draft-kappler-nsis-qosmodel-controlledload-01 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 November 13, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document describes a QoS Model to signal IntServ controlled load service with QoS NSLP. QoS NSLP is QoS Model agnostic. All QoS Model specific information is carried in an opaque object, the QSPEC. This document hence specifies the QSPEC for controlled load service, how the QSPEC must be processed in QoS NSLP nodes, and how QoS NSLP messages must be used to achieve IntServ controlled load service. Kappler Expires November 13, 2005 [Page 1]
Internet-Draft Controlled-Load QOSM May 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Signaling with QoS NSLP . . . . . . . . . . . . . . . . . . . 3 2.1 QoS NSLP . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 QSPEC . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.3 QoS Model . . . . . . . . . . . . . . . . . . . . . . . . 5 3. IntServ Controlled Load Service . . . . . . . . . . . . . . . 5 4. QoS Model for IntServ Controlled Load Service . . . . . . . . 6 4.1 Role of QNEs . . . . . . . . . . . . . . . . . . . . . . . 7 4.2 QSPEC . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.2.1 Controlled Load Service Requirements . . . . . . . . . 7 4.2.2 QOSM ID . . . . . . . . . . . . . . . . . . . . . . . 7 4.2.3 QSPEC Control Information . . . . . . . . . . . . . . 8 4.2.4 QoS Description . . . . . . . . . . . . . . . . . . . 8 4.3 Usage of QoS-NSLP Messages . . . . . . . . . . . . . . . . 9 5. Processing Rules in QNEs . . . . . . . . . . . . . . . . . . . 10 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 11 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 14 A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14 Intellectual Property and Copyright Statements . . . . . . . . 15 Kappler Expires November 13, 2005 [Page 2]
Internet-Draft Controlled-Load QOSM May 2005 1. Introduction The QoS NSIS Signaling Layer Protocol, QoS-NSLP [2] defines how to signal for QoS reservations in the Internet. The protocol is not bound to a specific mechanism for achieving QoS, such as IntServ or DiffServ. Rather, the actual QoS information is carried opaquely in the protocol in a separate object, the QSPEC [3]. A method for achieving QoS for a traffic flow using QoS NSLP signaling is called QoS model. It is expected that a number of QoS models will be developed for QoS-NSLP. Examples are [4], [5] and this draft. The purpose of this document is to describe a QoS model for controlled-load service of IntServ [6]. [7] specifies how to signal for controlled-load service with RSVP [8] . This document describes how to signal for the same service with QoS-NSLP. The controlled-load service is rather minimal both in terms of information that is signaled - basically bandwidth in the form of a token bucket - and in terms of prescribed realization of the service in the network. It is therefore suited for a wide range of realizations, such as reserving resources per-flow per-network node [9], achieving QoS in appropriately engineered DiffServ networks with admission control [10], or sending traffic via MPLS Label Switched Paths (LSPs) with reserved bandwidths and admission control [11][12]. The document is structured as follows: It gives a brief overview of QoS-NSLP and the QSPEC, and the content and features of a QoS model as described in [2] and [3]. It then gives a brief overview of the controlled-load service of IntServ. Subsequently, the actual QoS model for IntServ controlled-load service is described. 2. Signaling with QoS NSLP 2.1 QoS NSLP QoS NSLP [2] is an NSIS signaling layer protocol for signaling QoS reservations in the Internet. Together with GIMPS [13][14] , it provides functionality similar to RSVP and extends it, e.g. by supporting both sender-initiated and receiver-initiated reservations. QoS-NSLP however does not support multicast. QoS NSLP establishes and maintains reservation state in QoS-NSLP aware nodes, called QNEs, along the path of a data flow. The number or frequency of QNEs is not prescribed. The node initiating a reservation request is called QNI, the node terminating the request is called QNR. QNI and QNR are also QNEs, and are not necessarily the actual sender and receiver of the data flow they are signaling for as they may also be proxying for them. Kappler Expires November 13, 2005 [Page 3]
Internet-Draft Controlled-Load QOSM May 2005 QoS-NSLP defines four message types, RESERVE, QUERY, RESPONSE and NOTIFY. The message type identifies whether a message manipulates state (e.g. RESERVE) or not (e.g. QUERY, RESPONSE). The RESERVE message is used to create, refresh, modify or remove reservation state in QNEs. The QUERY message is used to request information about the data path without making a reservation. This functionality can be used to 'probe' the path for certain characteristics. The RESPONSE message is used to provide information about the results of a previous RESERVE or QUERY message, e.g. confirmation of a successful reservation, error, or for transferring results of a QUERY back towards the querying node. The NOTIFY message is not important in the context of this memo. 2.2 QSPEC QoS NSLP carries QoS Model specific information encapsulated in an opaque object, the QSPEC [3]. The QSPEC thus fulfills a similar purpose as TSpec, RSpec and AdSpec in RSVP [8]. The QSPEC is not processed by the QoS NSLP Processing unit on a QNE, but passed as-is to the Resource Management Function (RMD) on the same node, where it is interpreted. The QSPEC is structured internally into QSPEC Control Information, and QoS Description. o QSPEC Control Information contains parameters that govern the processing of the resource request in the RMF, e.g. information on excess treatment. o QoS Description describes the actual resources required and/or offered. It is composed of QSPEC objects, namely QoS Desired, QoS Available, QoS Reserved and Minimum QoS. A particular QoS Description typically only contains a subset of these objects. o * QoS Desired contains parameters describing the QoS desired by a QNI. * QoS Available contains parameters describing the available resources. This QSPEC object is used to collect information along a path. * QoS Reserved describes the actual QoS reserved * Minimum QoS can be included by a QNI together with QoS Desired to signal a range of QoS (between QoS Desired and Minimum QoS) is acceptable. Kappler Expires November 13, 2005 [Page 4]
Internet-Draft Controlled-Load QOSM May 2005 The QSPEC template [3] defines a number of mandatory and optional QSPEC parameters. Mandatory parameters must be interpreted by each QNE, whereas optional parameters can also be ignored. This ensures some degree of interoperability between QoS Models while at the same time providing extensibility and flexibility. In a given QoS Model, new optional parameters may be defined. The QSPEC usually carries a QoS Model identifier, which identifies what QoS Model is being signaled about. The QoS Model defines what parameters must be included in a given QSPEC. However, the QNI may also include additional parameters, in order to give additional information to QNEs that are not supporting this specific QoS Model, or to collect path information that is interesting to the QNI or other QNEs. 2.3 QoS Model A QoS-enabled domain supports a particular QoS model (QOSM), which is a method to achieve QoS for a traffic flow with QoS NSLP signaling, such as IntServ controlled load or DiffServ [15]. QoS NSLP is independent of the QOSM, just as RSVP [8] is independent of IntServ. A QOSM hence incorporates QoS provisioning methods and a QoS architecture. It however also defines how to use QoS NSLP. It defines the behavior of the resource management function (RMF), including inputs and outputs, and how QSPEC information on traffic description, resources required, resources available, and control information required by the RMF is interpreted. A QOSM also specifies the QSPEC parameters that describe the QoS and how resources will be managed by the RMF. 3. IntServ Controlled Load Service As specified in [6], the controlled-load service defined for IntServ supports applications which are highly sensitive to overload conditions, e.g. real-time applications. The controlled-load service provides to an application approximately the end-to-end service of an unloaded best-effort network. "Unloaded" thereby is used in the sense of "not heavily loaded or congested" rather than in the sense of "no other network traffic whatsoever". The definition of controlled-load service is intentionally imprecise. It implies a very high percentage of transmitted packets will be successfully delivered to the end nodes. Furthermore, the transit delay experienced by a very high percentage of the delivered packets will not greatly exceed the minimum transmit delay experienced by any successfully delivered packet. In other words, a short disruption of the service is viewed as statistical effect which may occur in normal operation. Events of longer duration are indicative of failure to Kappler Expires November 13, 2005 [Page 5]
Internet-Draft Controlled-Load QOSM May 2005 allocate sufficient resources to the controlled-load flow. In order to ensure that the conditions on controlled-load service are met, clients requesting the service provide network elements on the data path with an estimation of the data traffic they are going to generate. When signaling with RSVP, the object carrying this estimation is called TSpec. When signalign with QoS NSLP, the QSPEC object carrying desired resources is called <QoS Desired>. In return, the service ensures that in each network element on the data path, resources adequate to process traffic falling within this descriptive envelope will be available to the client. This must be accomplished by admission control. The controlled-load service is implemented per-flow in each network element on the data-path. Thereby, a network element may be an individual node such as a router. However, a network element can also be a subnet, e.g. a DiffServ cloud within a larger IntServ network [10]. In this case, the per-flow traffic description (e.g. carried in the RSVP TSpec) together with the DiffServ Code Point (carried e.g. in the DCLASS object [16] of RSVP) is used for admission control into the DiffServ cloud. The DiffServ cloud must ensure it provides controlled-load service. It is also possible to operate controlled-load service over logical links such as IP tunnels [12] or MPLS LSPs [11]. The per-flow traffic descriptor is in this case used for admission control into the tunnel /LSP. 4. QoS Model for IntServ Controlled Load Service According to [3], a QOSM SHOULD include the following information: o Role of QNEs in this QOSM: E.g. location, frequency, statefulness etc. o QSPEC Definition: A QOSM SHOULD specify the QSPEC, including QSPEC parameters. Furthermore it needs to explain how mandatory QSPEC parameters not used in this QOSM are mapped onto parameters defined therein. o Message sequencing and QSPEC object population, i.e. usage of QoS- NSLP messages to signal the QOSM. Message Format and QSPEC objects to be carried in RESERVE, QUERY RESPONSE and NOTIFY o State Management It describes how QSPEC info is treated and interpreted in the RMF and QOSM specific processing. E.g. admission control, scheduling, policy control, QoS parameter accumulation (e.g. delay). Subsequent sections treat these points one-by-one. Kappler Expires November 13, 2005 [Page 6]
Internet-Draft Controlled-Load QOSM May 2005 4.1 Role of QNEs Controlled-load service network elements can be individual routers or subnets. I.e. it is not necessary for each network node on the data path to interpret the signaling for the service. Rather, dedicated nodes may interpret signaling information and take on responsibility that the subnet they represent delivers adequate service. In fact, this setting maps nicely onto QoS-NSLP - and the NSIS protocol suite in general. In NSIS, QNEs are just required to be located on the data path. However there are no prescriptions regarding their number or frequency. This is in contrast to RSVP, where each router on the data path is expected to be RSVP-capable. Hence, in the controlled- load QoS model, there must be (at least) one QNE acting on behalf of every network element. E.g. all ingress routers to a DiffServ cloud could be QNEs, performing admission control. If there is more than one QNE per network element, they must be coordinated among themselves to ensure the network element delivers controlled-load service. 4.2 QSPEC 4.2.1 Controlled Load Service Requirements The controlled-load service uses a token bucket specification with a bucket rate r and a bucket depth b. The token bucket also includes peak rate (p), a minimum policed unit (m) and a maximum packet size (M) to describe a data flow's required resources. The minimum policed unit m is an integer measured in bytes. All IP data grams of size less than m are counted against the token bucket as being of size m. For more details, including value ranges of the parameters see [7]. The controlled-load service has no required characterization parameters the QNI needs to be informed about, i.e. current measurement and monitoring information need not be exported by QNEs, although individual implementations may do so if they wish. When using RSVP to signal for controlled-load services, the PATH message collects information on MTU which is used by the receiver to adapt the reservation parameters in the RESV message. While this is one possible way for signaling controlled load services, this is not prescribed by the controlled load service itself. 4.2.2 QOSM ID Later versions of this document will define a QOSM ID. Kappler Expires November 13, 2005 [Page 7]
Internet-Draft Controlled-Load QOSM May 2005 4.2.3 QSPEC Control Information No QSPEC Control Information is necessary. Information on Excess Treatment (drop or reshape) may be included. Note the original controlled load service specification leaves it up to network elements (i.e. QNEs) how to treat non-comforming traffic. It is unclear to what extent this treatment can be prescribed. In RSVP, when non-IntServ hops are discovered on the path, a flag is raised. Additionally, the number of IntServ hops is counted. This way a sender or receiver can determine whether end-to-end QoS could be achieved. The QSPEC template defines similar parameters, particularly <non- QOSM-hops> and <QOSM hops>. They flag/count the number of QNEs on the data path (not) supporting the QOSM identified in the QSPEC. Together with a counter/flag in QoS NSLP which identifying hops not supporting QoS NSLP they provide sufficient information. The benefit however in this case is still unclear: All QSPEC parameters necessary for controlled load service are mandatory parameters. This means even if a QNE does not support the controlled load service QOSM, it is still able to make sense of the parameters and reserve QoS accordingly. 4.2.4 QoS Description The controlled load QOSM uses only mandatory parameters defined in [3]. <QoS Desired> = <token bucket>(<QoS Class>) <QoS Available> = (<bandwidth><path latency>)<MTU> <Minimum QoS> = <token bucket>>(<QoS Class>) <QoS Reserved> = <token bucket> OR <MTU> Of these, only <QoS Desired> and <QoS Reserved> will be used by all implementations. Including <QoS Class> allows to also cover scenarios in which the flow passes a DiffServ cloud. This is also foreseen when signaling for controlled load with RSVP [16]. <QoS Available> is necessary for receiver-initiated reservations, and MAY be used in sender-initiated reservations. It is used for gathering path characteristics such as <MTU>. This information can be used by QNI or QNR to update the reservation, particularly to re- issue a failed reservation. For controlled load service, additionally gathering information on bandwidth and path latency is Kappler Expires November 13, 2005 [Page 8]
Internet-Draft Controlled-Load QOSM May 2005 desirable (TBD why; this is how it is done in RSVP). Note <path latency> is an optional parameter, i.e. some QNEs may not understand it. However, such QNEs are required to raise a corresponding flag. In this case the value collected in <path latency> is a lower bound to the actual value. <Minimum QoS> is optional. It always travels together with <QoS Desired>. It signifies that the QNI can accept a downgrade of resources for particular parameters in the reservation, down to the value of the respective parameter in <Minimum QoS>. For parameters not appearing in <Minimum QoS>, it cannot accept a downgrade. For controlled load service this means if <token bucket> is included, a downgrade of all token bucket parameters within the designated range is acceptable. If <MTU> is included only, only the maximum packet size issued by the QNI is negotiable (remember the token bucket also includes a maximum packet size parameter) In all QSPEC objects additional parameters MAY be included, as described in [3]. Future versions of this draft will include a description of how other mandatory QSPEC parameters which are not used in the controlled load QOSM are treated by by QNEs implementing the controlled load QOSM 4.3 Usage of QoS-NSLP Messages QoS-NSLP allows a variety of message sequences for reserving resources. Particularly, sender-initiated, receiver-initiated and bi-directional messages are possible. E.g., in sender-initiated reservations, a RESERVE is issues by the QNI. If the reservation is successful, the QNR replies with a RESPONSE. If the reservation fails, the QNE at which it failed sends a RESPONSE. For a given message sequence, the QSPEC template defines what QSPEC objects travel in which of these messages, and how they are translated from message-to-message. For each of the message sequence defined in QoS NSLP, a variety of QSPEC object usages is possible. o in sender-initiated reservations, the RESERVE may carry just <QoS Desired> to indicate the exact QoS it wants, and the corresponding RESPONSE carries solely <QoS Reserved>. This implies either the exact resources described in <QoS Desired> are reserved, or the reservation fails. o in another sender-initiated reservation, a more fancy QNI would include, in addition to <QoS Desired>, a <QoS Available> QSPEC object, or even a <Minimum QoS>. <QoS Available> allows collecting path properties, e.g. MTU and currently available bandwidth, and Kappler Expires November 13, 2005 [Page 9]
Internet-Draft Controlled-Load QOSM May 2005 <Minimum QoS> signals that (and how much) less resources than <QoS Desired> are acceptable. The RESPONSE message carries <QoS Reserved>, and additionally copies the <QoS Available> QSPEC Object from RESERVE, this way informing the QNI e.g. about the MTU. This information may be of particular interest if a reservation failed. Note however, that the QNE failing the reservation sends the RESPONSE, such that this way no complete e2e information on e.g. MTU can be collected. Note also that QNIs usually are flexible about MTU and can just add a <Minimum QoS> with a <MTU = 0> parameter set. Generally, it needs to be discussed what is the most efficient way of providing feedback to the QNI for sender-initiated reservations. Note that the initial message and the QSPEC objects therein fully determines the sequencing of subsequent messages, and also determines what QSPEC objects will be carried in them. The controlled load service can be signaled with any of the message exchanges and QSPEC object combinations defined in [2] and [3]. Note, in contrast, in RSVP only one type of message exchange is defined (receiver-initiated reservations, and the equivalent of <Minimum QoS> = <MTU = 0>.). However, this is a characteristic of RSVP rather than of the controlled load service. 5. Processing Rules in QNEs Admission Control: For controlled-load service, QNEs are required to perform admission control. All resources important to the operation of the network element must be considered when admitting a request. Common examples of such resources include link bandwidth, router or switch port buffer space, and computational capacity of the packet forwarding engine. It is not prescribed how a QNE determines adequate resources are available. It is however required that they make bandwidth greater than the token rate available to the flow in certain situations in order to account for fluctuations. E.g. statistical methods may be used to determine how much bandwidth is necessary. There are no target values for other parameters, e.g. delay or loss, other than providing a service closely equivalent to that provided to best-effort traffic under lightly loaded conditions. QNEs must reject a service request (by returning an admission control error) if the maximum packet size M signaled in <QoS Desired>, resp. in <.Minimum QoS> if available, is bigger than the MTU of the segment of the path managed by this QNE. Kappler Expires November 13, 2005 [Page 10]
Internet-Draft Controlled-Load QOSM May 2005 Resource requests for new flows are accepted if capacity is available. Reservation modifications are accepted if the new <.token bucket> is strictly smaller than the old one (for rules for ordering token buckets see [6]). Otherwise they are treated like new reservations from an admission control perspective. Packet Scheduling: No specific scheduling mechanism is prescribed, as long as admitted flows receive appropriate service. Policy Control: The controlled-load service is provided to a flow on the basis that the flow's traffic conforms to the traffic parameters signaled at flow setup time. Packets arriving when no tokens are available, or arriving with a rate greater than the peek rate, are considered non- conformant. QNEs are allowed to somewhat delay packets for making them conformant (i.e. to reshape the flow) unless <.Excess Treatment> was included saying non-conformant packets must be dropped. Links are not permitted to fragment packets which receive the controlled-load service. Packets larger than the MTU of the link must be treated as non-conformant. Nonconformant packets should be forwarded on a best-effort basis, as long as the contracted QoS of other flows is not compromised, and as long as best-effort traffic is not impacted unfairly. The mechanism for implementing this policy is not prescribed. E.g. it would be possible to degrade the service delivered to the entire flow which originated the nonconformant packets, or to just degrade or even drop nonconformant packets (such as packets larger than the MTU). Note each QNE MUST independently ensure other flows are not impacted by non-conforming packets. 6. Security Considerations This Internet Draft raises no new security issues. 7. Conclusions This document describes a QoS Model to signal IntServ controlled load service with QoS NSLP. Up to now, it was only described how to signal for IntServ controlled load service with RSVP [6]. Since no independent document exists that describes IntServ controlled load by its own, i.e. without RSVP, it is sometimes difficult to determined what features described in [6] are specific to IntServ controlled load, and which features are specific to RSVP: Kappler Expires November 13, 2005 [Page 11]
Internet-Draft Controlled-Load QOSM May 2005 o Is it indeed vital for QNIs signaling for controlled load service to be informed about the number of hops not implementing this QOSM? Since the controlled load QOSM exclusivly relies on mandatory parameters it can be expected that all QNEs can make sense of the reservation, independent of whether they explicitly implement controlled load service or not. Of more interest appears the number of non-QoS-NSLP hops (which is collected in the main message body of QoS NSLP rather than in the QSPEC). o Why is it necessary to collect delay and bandwidth information along the data path? The result of the collection does not seem to influence the reservation process. o The QoS NSLP QOSM for controlled load service allows a variety of message exchanges all eventually resulting in a reservation, e.g. sender-initiated, receiver-initiated and bidirectional signaling. The controlled load service when signaled with RSVP was bound to sender-initiated reservations. o When signaling with RSVP, it is not possible to define a range of acceptable QoS. Also this seems to be a charcteristic of RSVP rather than a feature of the controlled load service. An issue of general interest discovered here concerns feedback of information in sender-initiated scenarios (In receiver-initiated scenarios it does not occurr because path information is collected before the RESERVE is issued). A QNI may include in <QoS Available> several parameters, e.g. MTU, it would like to measure along the data path. If the reservation fails, e.g. because the maximum packet size was to large, the QNE failing the reservation returns a RESPONSE, including the <QoS Available> QSPEC object with accumulated information up to this point. The QNI can learn from this why the reservation failed (because the MTU is less than the maximum packet size in this example) at this particular QNE. However it cannot be sure a subsequent downgraded RESERVE will be more successful. This is because there may be even more difficult conditions (e.g. even smaller MTU) down the path. That is, in sender-initiated scenarios it is not straightforward to receive feedback from a failed reservation that allows to make a good guess at what size of reservation would be more successful. Of course it would be possible for the QNI to issue a QUERY first to find out about a suitable value for, e.g. maximum packet size. However this adds another round-trip time to the reservation, thereby obsoleting one of the main benefits of sender-initiated reservations compared to receiver-initiated ones. In this draft, the feedback problem is solved by including a <Minimum QoS> QSPEC object in sender-initated reservations. This gives some flexibility as it implicitly says the QNI would also accept a Kappler Expires November 13, 2005 [Page 12]
Internet-Draft Controlled-Load QOSM May 2005 downgraded reservation, up to the value specified. When the maximum packet size in < Minimum QoS is set to a very small value reservations are not going to fail because of a MTU problem. Note however as currently specified in [3], the <Minimum QoS> QSPEC object is not necessarily supported by all QNEs. 8. References [1] Brunner, M., "Requirements for Signaling Protocols", RFC 3726, April 2004. [2] Bosch, S., Karagiannis, G., and A. McDonald, "NSLP for Quality- of-Service signaling", draft-ietf-nsis-qos-nslp-06 (work in progress), February 2005. [3] Ash, J., "QoS-NSLP QSpec Template", draft-ietf-nsis-qspec-03 (work in progress), February 2005. [4] Bader, A., "RMD-QOSM - The Resource Management in Diffserv QoS model", draft-ietf-nsis-rmd-01 (work in progress), February 2005. [5] Ash, J., "Y.1541-QOSM -- Y.1541 QoS Model for Networks Using Y.1541 QoS Classes", draft-ash-nsis-y1541-qosm-00 (work in progress), May 2005. [6] Wroclawski, J., "Specification of the Controlled-Load Network Element Service", RFC 2211, September 1997. [7] Wroclawski, J., "The Use of RSVP with IETF Integrated Services", RFC 2210, September 1997. [8] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997. [9] Braden, B., Clark, D., and S. Shenker, "Integrated Services in the Internet Architecture: an Overview", RFC 1633, June 1994. [10] Bernet, Y., Ford, P., Yavatkar, R., 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. [11] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. [12] Terzis, A., Krawczyk, J., Wroclawski, J., and L. Zhang, "RSVP Kappler Expires November 13, 2005 [Page 13]
Internet-Draft Controlled-Load QOSM May 2005 Operation Over IP Tunnels", RFC 2746, January 2000. [13] Schulzrinne, H., "GIMPS: General Internet Messaging Protocol for Signaling", draft-ietf-nsis-ntlp-05 (work in progress), February 2005. [14] Hancock, R., "Next Steps in Signaling: Framework", draft-ietf-nsis-fw-07 (work in progress), December 2004. [15] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., and W. Weiss, "An Architecture for Differentiated Services", RFC 2475, December 1998. [16] Bernet, Y., "Format of the RSVP DCLASS Object", RFC 2996, November 2000. Author's Address Cornelia Kappler Siemens AG Siemensdamm 62 13627 Berlin Germany Email: cornelia.kappler@siemens.com Appendix A. Acknowledgements The author would like to thank Andrew McDonald for fruitful discussions. Kappler Expires November 13, 2005 [Page 14]
Internet-Draft Controlled-Load QOSM May 2005 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 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. 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 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. Copyright Statement Copyright (C) The Internet Society (2005). 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. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Kappler Expires November 13, 2005 [Page 15]
