Internet Engineering Task Force James Polk Internet Draft Subha Dhesikan Expiration: Jan 12th, 2005 Cisco Systems File: draft-polk-rsvp-aggregate-reduction-00.txt RSVP Extension for Bandwidth Reduction of an Aggregate July 12th, 2004 Status of this Memo By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. 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. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document proposes an extension to the Resource Reservation Protocol (RSVP) that allows an aggregated reservation to be partially preempted. Currently, when a higher priority reservation request arrives and sufficient bandwidth is unavailable to meet that request, a lower priority aggregated reservation may be preempted in whole, whether or not the entire bandwidth is required. This document describes a method where the lower priority aggregated reservation is preempted only to the extent to which its bandwidth is required for the higher priority request. This allows the aggregator to fail only a portion of the individual sessions that is aggregated and allow the rest of the sessions to continue unaffected. Polk & Dhesikan [Page 1]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1 Conventions . . . . . . . . . . . . . . . . . . . . . . 3 2. RSVP Aggregation Overview . . . . . . . . . . . . . . . . . . 3 3. RSVP Aggregation Reduction Scenario . . . . . . . . . . . . . 5 4. Aggregate Reservation Reduction Requirements . . . . . . . . 6 5. Aggregate Bandwidth Reduction Solution . . . . . . . . . . . 7 5.1 Partial Preemption Error Code . . . . . . . . . . . . . 8 5.2 Error Flow Descriptor . . . . . . . . . . . . . . . . . 9 6. Currently Known Open Issues . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . 9 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 Appendix. Walking Through the Solution . . . . . . . . . . . . . 11 10 References . . . . . . . . . . . . . . . . . . . . . . . . . 13 10.1 Normative References . . . . . . . . . . . . . . . . . . 13 10.2 Informational References . . . . . . . . . . . . . . . . 14 11. Author Information . . . . . . . . . . . . . . . . . . . . . 14 1. Introduction This document proposes an extension to the Resource Reservation Protocol (RSVP) [1] that allows an aggregated reservation to be partially preempted. RSVP aggregation [2] provides a mechanism to combine many individual RSVP sessions into a single aggregated session. The benefit of aggregation is that it greatly reduces the number of messages that is exchanged between the routers and the state that is maintained, leading to a savings in the CPU and memory resources. Thus, RSVP aggregation greatly helps in the scaling of an RSVP solution. With RSVP aggregation, a situation can arise in which two aggregate flows with differing priority levels will traverse the same router interface. This should be a common occurrence in larger networks even using RSVP aggregation because each flow (whether an aggregate or not) follows IP routing paths determined by the routing protocol (BGP, OSPF, etc). However, if that router interface reaches bandwidth capacity and is then asked either through a new RESV reservation set-up message, or the expansion of an existing aggregate, to set-up a new or greater bandwidth reservation, the router has to make a choice: deny the new request (because all available resources are at full utilization) or preempt an existing lower priority reservation to make room for the new or expanded reservation. When the flows are individual, this has little adverse affect other than on the denied or preempted flows. If the flow being preempted is an aggregate of many individual flows, this has greater consequences. While [2] clearly does not terminate all the individual flows if an aggregate is denied, this event will cause Polk & Dhesikan [Page 2]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 packets to be discarded. This document describes a method where only the minimum required bandwidth is taken away from the lower- priority aggregated reservation and the entire reservation is not preempted. This will usually be close to the amount that was just increased in another flow at that interface. This has the advantage that only some of the microflows making up the aggregate are affected. Without this extension, all individual flows are affected and the deaggregator will have to re-attempt the reservation request with a reduced bandwidth. Not knowing by how much bandwidth an aggregate was preempted for compounds the problem as the deaggregator does not know how much bandwidth to ask for to receive the maximum available. In addition, there is a risk that some other (new or expanding) reservation is granted the remaining bandwidth during this reestablishment time period. Note that when this document refers to a router interface being "full" or "at capacity", this does not imply that all of the bandwidth has been used, but rather than all of the bandwidth available for reservation via RSVP under the applicable policy has been used. Policies for real-time traffic routinely reserve capacity for routing and for elastic applications, and may distinguish between voice, video, and other real time applications. Section 2 will describe the extensions with the necessary diagrams. Section 3 will address the protocol changes necessary to RSVP to allow this to become possible. This document is intended to be classified as an 'update' to RFC 3181 [3] if published as an RFC. 1.1 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 [4]. 2. RSVP Aggregation Overview The following network topology is to help visualize the concerns this document addresses. Figure 1 consists of 10 routers (the boxes) and 11 flows (1, 2, 3, 4, 5, 9, A, B, C, D, and E). Initially there will 5 flows per aggregate (flow 9 will be introduced to cause the problem we are addressing in this document), with 2 aggregates (A & B); (1 through 5) in aggregate A and (A through E) in aggregate B. These 2 aggregates will cross one router interface utilizing all available capacity (in this example). RSVP is a reservation establishment protocol in one direction only. It is up to the endsystems to request 2 one-way reservations if that is what is needed for a particular application (like voice calls). Please refer to [1] for the details on how this functions. RSVP Polk & Dhesikan [Page 3]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 aggregation [per 2] is no different (operating in one direction). This split path philosophy is because the routed path from one device to the other in one direction, might not be the routed path for communicating between the same two endpoints in the reverse direction. RSVP in [3] established a priority indication for each flow. In fact, there are two priority indications: one to establish the reservation, and one to defend the reservation in case preemption is possible. Aggregate A will have a higher establishing priority than aggregate B has for its defending priority. This means that if aggregate A wants more bandwidth and none is available at an Aggregator of A Deaggregator of A | | V V +------+ +------+ +------+ +------+ Flow 1-->| | | | | | | |--> Flow 1 Flow 2-->| | | | | | | |--> Flow 2 Flow 3-->| |==>| | | |==>| |--> Flow 3 Flow 4-->| | ^ | | | | ^ | |--> Flow 4 Flow 5-->| | | | | | | | | |--> Flow 5 Flow 9 | Rtr1 | | | Rtr2 | | Rtr3 | | | Rtr4 | Flow 9 +------+ | +------+ +------+ | +------+ | || || | Aggregate A-->|| Aggregate A ||<--Aggregate A || | || +--------------+ | +--------------+ | |Int 7 | | |Int 1 | | | +----- | V |------+ | | Rtr10 |Int 8 |===========>|Int 2 | Rtr11 | | | |:::::::::::>| | | | +----- | ^ |------+ | | |Int 9 | | |Int 3 | | +--------------+ | +--------------+ .. | .. Aggregate B--->.. Aggregate B ..<---Aggregate B | .. .. | +------+ | +------+ +------+ | +------+ Flow A-->| | | | | | | | | |--> Flow A Flow B-->| | V | | | | V | |--> Flow B Flow C-->| |::>| | | |::>| |--> Flow C Flow D-->| | | | | | | |--> Flow D Flow E-->| Rtr5 | | Rtr6 | | Rtr7 | | Rtr8 |--> Flow E +------+ +------+ +------+ +------+ ^ ^ | | Aggregator of B Deaggregator of B Figure 1. Generic RSVP Aggregate Topology Polk & Dhesikan [Page 4]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 interface, aggregate B will have to relinquish bandwidth in favor of this higher priority aggregate (A). The priorities assigned to a reservation are always end-to-end, and not altered by any routers in transit. Figure 1 legend/rules: - Aggregate A priority = 100 - Aggregate B priority = 200 - All boxes are Routers - Both aggregates are shown in the same direction (left to right). Corresponding aggregates in the reverse direction are not shown for diagram simplicity The path for aggregate A is: Rtr1 => Rtr2 => Rtr10 => Rtr11 => Rtr3 => Rtr4 where aggregate A starts in Rtr1, and deaggregates in Rtr4. Flows 1, 2, 3, 4, 5 and 9 communicate through aggregate A The path for aggregate B is: Rtr5 ::> Rtr6 ::> Rtr10 ::> Rtr11 ::> Rtr7 ::> Rtr8 where aggregate B starts in Rtr5, and deaggregates in Rtr8. Flows A, B, C, D and E communicate through aggregate B Both aggregates share one leg or physical link: between Rtr10 and Rtr11, thus they share one outbound interface: Int8 of Rtr10, where contention of resources may exist. That link has an RSVP capacity of 800kbps. RSVP signaling (messages) is outside this 800kbps in this example, as is any session signaling protocol like SIP. 3. RSVP Aggregation Reduction Scenario Figure 1 shows an established aggregated reservation (aggregate A) between the routers rtr1 and rtr4. This aggregated reservation consists of 5 microflows (flow 1, 2, 3, 4, 5). For the sake of this discussion, let us assume that each flow represents a voice call and requires 80kb (such as for the codec G.711) with no silence suppression. Aggregate A request is for 400kbps (80kbps * 5 flows). The priority of the aggregate is derived from the individual microflows that it is made up of. In the simple case, all flows of a single priority are bundled as a single aggregate (another priority level would be in another aggregate, even if traversing the same path through the network). There may be other ways in which the priority of the aggregate is derived, but for this discussion it is sufficient to note that each aggregate contains a priority (both Polk & Dhesikan [Page 5]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 hold and defending priority). The means of deriving the priority is out of scope for this discussion. Aggregate B, in Figure 1, consists of flows A, B, C, D and E and requires 400kbps (80kbps * 5 flows), and starts at rtr5 and ends rtr8. This means there are two aggregates occupying all 800kbps of the RSVP capacity. When Flow 9 is added into aggregate A, this will occupy 80kbps more than Int8 on rtr10 has available (880k offered vs. 800k capacity) [1] and [2] create a behavior in RSVP to deny the entire aggregate B and all its individual flows because aggregate A has a higher priority. This situation is where this document focuses its requirements and calls for a solution. There should be some means to signal to all affected routers of aggregate B that only 80kbps is needed to accommodate another (higher priority) aggregate. A solution that accomplishes this reduction instead of a failure could: - reduce significant packet loss of all flows within aggregate B During the re-reservation request period of time no packets will traverse the aggregate until it is reestablished. - reduces the chances that the reestablishment of the aggregate will reserve an inefficient amount of bandwidth, causing the likely preemption of more individual flows at the aggregator than would be necessary had the aggregator had more information (that RSVP does not provide at this time) During reestablishment of the aggregation in Figure 1. (without any modification to RSVP), rtr8 would guess at how much bandwidth to ask for in the new RESV message. It could request too much bandwidth, and have to wait for the error that not that much bandwidth was available; it could request too little bandwidth and have that aggregation accepted, but this would meant that more individual flows would need to be preempted outside the aggregate than were necessary, leading to inefficiencies in the opposite direction. 4. Requirements for Aggregate Reservation Reduction The following are the requirements to reduce the bandwidth of an aggregate reservation: Req#1 - MUST have the ability to differentiate one aggregate from other flows. It might be the case that there is only one aggregate at an interface that is now forced (by some means) to make the choice to preemption the entire aggregate or reduce its bandwidth. Polk & Dhesikan [Page 6]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 Req#2 - MUST have the ability to indicate within an RSVP error message (generated at the router with the congested interface) that a specific aggregate is to be reduced in bandwidth, which is less than it currently has reserved. The indication should be to the maximum bandwidth still able to be utilized instead of what has been reduced, because of the unreliable nature of RSVP messaging. If a reduction message were lost, another one needs to be sent. If the receiver ends up receiving two copies to reduce the bandwidth of a reservation by some amount, it is likely the router will reduce the bandwidth by twice the amount that was actually call for. This is not appropriate. Req#3 - MUST have the ability to indicate within the same error message the new maximum amount of bandwidth that is available to be utilized within the existing reservation, but no more. A note to the reader (or WG): it is probable that whatever indication of bandwidth reduction is chosen will apply for individual reservation reduction as well as to aggregates. An example of this would be an established reservation for a voice call with a codec that uses (say) 80kbps, when a congested interface indicates 80kbps is no longer available, but anything less than 40kbps is available. The endpoints could signal (using a protocol such as SIP in [8] and [9]) to maintain the call, but at a lower bandwidth codec (such as G.729). This could prevent a policy that states something like: "calls shall use RSVP, or no call occurs" (thus preventing communication that could exist with a lower bandwidth codec) or a more realistic policy in which a reservation is required for establishment, but once the reservation is preempted, the call is to relying on Differentiated Services or a scavenger class of traffic (not knowing a codec requiring less bandwidth could be used and the endpoints could adjust the reservation to the lower available bandwidth). Comments to this document could shift the authors' direction of this document to include this larger scenario, if it isn't true by default already. 5. RSVP Bandwidth Aggregation Reduction Solution When an aggregated reservation is partially preempted, a ResvErr (Reservation Error) message is generated just as it is done currently with preemptions. The error spec object and the preemption pri policy object are included as well. Very few Polk & Dhesikan [Page 7]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 additions/changes are needed to the ResvErr message to support partial preemptions. A new error sub code is required and is defined in section 5.1. The error flowspec contained in the ResvErr message indicates the flowspec that is reserved and this flowspec may not match or be less than the original reservation request. This is defined in section 5.2. A comment about RESV message not using a reliable transport. This document recommends that ResvErr message be made reliable by implementing RFC 6. There is an issue with the current operational behavior of RSVP [per 1] to transmit an ResvTear message upstream when the ResvErr message is transmitted downstream. This ResvTear message terminates the reservation to all routers upstream of the router where the preemption occurred. This document is written to prevent the tearing down of a reservation, even part of a reservation. Thus, the router that normally would generate a ResvTear message MUST NOT do so. An appendix has been written to walk through the overall solution to the problems presented in section 3. There is a suggestion within the appendix at addressing this ResvTear transmission issue. The authors will look for comments on how best address this. 5.1 Partial Preemption Error Code The ResvErr message that is caused due to preemption includes the Error Spec object as well as the Preemption Priority Policy object. The format of Error-spec objects is defined in [1]. The error code listed in the ERROR_SPEC object for preemption [5] currently is as follows: Errcode = 2 (Policy Control Failure) and ErrSubCode = 5 (ERR_PREEMPT) The following error code is suggested in the Error_spec object for partial preemption: Errcode = 2 (Policy Control Failure) and ErrSubCode = X (ERR_PARTIAL_PREEMPT) Where 'X' is the number assigned by IANA for this error code There is also an error code in the preemption-pri policy object. This error code takes a value of 1 to indicate that the admitted flow was preempted [3]. The same error value of 1 may be used for the partial preemption case as well. Polk & Dhesikan [Page 8]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 5.2 Error Flow Descriptor The error flow descriptor is defined in [1] & [7]. In the case of partial preemption, the flowspec contained in the error flow descriptor indicates the highest average and peak rates that the preempting system can accept in the next RESV message. The deaggregator must reduce its reservation to a number less than or equal to that, whether by changing codecs, by dropping reservations, or some other mechanism. 6. Currently Known Open Issue This section lists the known open issues to date. #1 - This general type of error to a preempted aggregate may be able to be applied to a new aggregate request as well. Should this document take on the task of addressing the case in which a new aggregate asks for X amount of bandwidth, but X-n amount is all that is available through the path? This will require a new policy error code (TBD) but with the same error flow descriptor with the currently available bandwidth. Additional behaviors of RSVP will be necessary as well. #2 - Whether individual reservation flows should be addressed in this effort as well. The scenario is given below requirement #3 in section 4 of this document. It has to do with a preempted individual flow should have an error indicating to the endpoint that if it would accept less bandwidth, a reestablishment could probably occur between endsystems. This could provide a preferential handling of resources to those systems that are already engaged in reservations by informing them of the available resources between two endsystems. #3 - Have not addressed the ResvTear transmission specified in [1]. This is called out in section 5, and in the appendix. The appendix offers a suggestion, but the authors are looking for feedback before proceeding with this issue. #4 - (perhaps related to issue #3) Admittedly have not addressed what happens if this error message is generated (and sent) and the flow doesn't reduce itself in a timely fashion (implying the message was lost or it was received and not adhered to). Comments and guidance on these open issues is requested, as each would require extension of this document into a wider problem space. 7. Security Considerations This document does not lessen the overall security of RSVP or of reservation flows through an aggregate. Polk & Dhesikan [Page 9]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 8. IANA Considerations IANA is to assign the following from RFC [XXXX] (this document): The following error code is to be defined in the Error_spec object for partial preemption under "Errcode = 2 (Policy Control Failure)": ErrSubCode = X (ERR_PARTIAL_PREEMPT) Where 'X' is assigned by IANA for this error code The behavior of this ErrSubCode is defined in this document. 9. Acknowledgements The authors would like to thank Fred Baker for contributing text and guidance in this effort and to Roger Levesque for helpful comments. Polk & Dhesikan [Page 10]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 Appendix 1. Walking Through the Solution Here is a concise explanation of roughly how RSVP behaves with the solution to the problems presented in sections 2 & 3 of this document. There is no normative text in this appendix. Here is a duplicate of Figure 1 from section 2 of the document body (to bring it closer to the detailed description of the solution). Aggregator of A Deaggregator of A | | V V +------+ +------+ +------+ +------+ Flow 1-->| | | | | | | |--> Flow 1 Flow 2-->| | | | | | | |--> Flow 2 Flow 3-->| |==>| | | |==>| |--> Flow 3 Flow 4-->| | ^ | | | | ^ | |--> Flow 4 Flow 5-->| | | | | | | | | |--> Flow 5 Flow 9 | Rtr1 | | | Rtr2 | | Rtr3 | | | Rtr4 | Flow 9 +------+ | +------+ +------+ | +------+ | || || | Aggregate A--->|| Aggregate A ||<--Aggregate A || | || +--------------+ | +--------------+ | |Int 7 | | |Int 1 | | | +----- | V |------+ | | Rtr10 |Int 8 |===========>|Int 2 | Rtr11 | | | |:::::::::::>| | | | +----- | ^ |------+ | | |Int 9 | | |Int 3 | | +--------------+ | +--------------+ .. | .. Aggregate B--->.. Aggregate B ..<---Aggregate B | .. .. | +------+ | +------+ +------+ | +------+ Flow A-->| | | | | | | | | |--> Flow A Flow B-->| | V | | | | V | |--> Flow B Flow C-->| |::>| | | |::>| |--> Flow C Flow D-->| | | | | | | |--> Flow D Flow E-->| Rtr5 | | Rtr6 | | Rtr7 | | Rtr8 |--> Flow E +------+ +------+ +------+ +------+ ^ ^ | | Aggregator of B Deaggregator of B Duplicate of Figure 1. Generic RSVP Aggregate Topology Looking at Figure 1., aggregate A (with five 80kbps flows) traverses: Rtr1 ==> Rtr2 ==> Rtr10 ==> Rtr11 ==> Rtr3 ==> Rtr4 Polk & Dhesikan [Page 11]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 And aggregate B (with five 80kbps flows) traverses: Rtr5 ::> Rtr6 ::> Rtr10 ::> Rtr11 ::> Rtr7 ::> Rtr8 Both aggregates are 400kbps. This totals 800kbps at Interface-7 in Rtr10, which is the maximum bandwidth RSVP has access to at this interface. Signaling messages still traverse the interface without problem. Aggregate A is at a higher relative priority than aggregate B. Local policy in this example is for higher relative priority flows to preempt lower priority flows during times of congestion. The following points describe the flow when aggregate A is increased to include flow 9. o When flow 9 (at 80kbps) is added to aggregate A, Rtr1 will initiate the PATH message towards the destination endpoint of the flow. This hop-by-hop message will take it through Rtr2, Rtr10, Rtr11, Rtr3 and Rtr4 which is the aggregate A path (that was built per [2] from the aggregate's initial set up) to the endpoint node. o In response, Rtr4 will generate the RESV message reservation [defined behavior per 1]. This RESV from the deaggregator indicates an increase bandwidth sufficient to accommodate the existing 5 flows (1,2,3,4,5) and the new flow (9) [as stated in 2]. o As mentioned before, in this example, Int8 in RTR 10 can only handle 800kbps, and aggregates A and B have each already established 400kbps flows comprised of five 80kbps individual flows. Therefore, Rtr10 (the interface that detects a congestion event in this example) must make a decision about this new congestion generating condition in regard to the RESV message received at Int8. o Local Policy in this scenario is to preempt lower priority reservations to place higher priority reservations. This would normally cause all of aggregate B to be preempted just to accommodate aggregate AÆs request for an additional 80kbps. o This document defines how aggregate B is not completely preempted, but reduced in bandwidth by 80kbps. This is contained in the ResvErr message that Rtr10 generates (downstream) towards Rtr11, Rtr7 and Rtr8. See section 5 for the details of the error message. o Rtr8 is the deaggregator of aggregate B. The deaggregator controls all the parameters of a reservation. This will be the node that reduces the individual flows into it (perhaps picking on Flow D for individual preemption by generating a ResvErr towards that endpoint). Polk & Dhesikan [Page 12]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 o Normal operation of RSVP is to have the router that generates a ResvErr message downstream to also generate a ResvTear message upstream (in the opposite direction). The ResvTear message terminates an individual flow or aggregate flow. This document calls for that message to not be sent immediately. The authors have not solved (yet) whether the ResvTear should be sent out at all and if so, how much of a delay there needs to be before this message is sent. Suggestions are asked for in this regard, but it is possible the next bullets can solve this issue: o Once Rtr8 preempts whichever individual flow (or 'bandwidth' at the aggregate ingress), it transmits a new RESV message for that aggregate (B), not for a new aggregate. This RESV from the deaggregator indicates an decrease in bandwidth sufficient to accommodate the remaining 4 flows (A,B,C,E), which is now 320kbps (in this example). o This message travels the entire path of the reservation, resetting all routers to this new aggregate bandwidth value. This should be what is necessary to prevent a ResvTear message from being generated by Rtr10 towards Rtr6 and Rtr5. Rtr5 will not know through this RESV message which individual flow was preempted. In this case, the voice signaling protocol (SIP) will generate a termination of the flow at layer 7 to stop the flow of packets into Rtr5. 10. References 10.1 Normative References [1] R. Braden, Ed., L. Zhang, S. Berson, S. Herzog, S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997 [2] F. Baker, C. Iturralde, F. Le Faucheur, B. Davie, "Aggregation of RSVP for IPv4 and IPv6 Reservations", RFC 3175, September 2001 [3] S. Herzog, "Signaled Preemption Priority Policy Element", RFC 3181, October 2001 [4] Bradner S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997 [5] S. Herzog, "RSVP Extensions for Policy Control", RFC 2750, January 2000 [6] L. Berger, D. Gan, G. Swallow, P. Pan, F. Tommasi, S. Molendini, "RSVP Refresh Overhead Reduction Extensions" RFC 2961, April 2001 Polk & Dhesikan [Page 13]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 [7] J. Wroclawski, "The Use of RSVP with IETF Integrated Services", RFC 2210, September 1997 10.2 Informational References [8] J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, May 2002. [9] G. Camarillo, Ed., W. Marshall, Ed., J. Rosenberg, "Integration of Resource Management and Session Initiation Protocol (SIP)", RFC 3312 Preconditions, October 2002 11. Author Information James M. Polk Cisco Systems 2200 East President George Bush Turnpike Richardson, Texas 75082 USA Email: jmpolk@cisco.com Subha Dhesikan Cisco Systems 170 W. Tasman Drive San Jose, CA 95134 USA Email: sdhesika@cisco.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 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 Polk & Dhesikan [Page 14]
Internet Draft RSVP Aggregate Reduction July 12th, 2004 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 (2004). 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. The Expiration date for this Internet Draft is: Jan 12th, 2005 Polk & Dhesikan [Page 15]