Internet Engineering Task Force J. Manner (ed.) Internet-Draft X. Fu (ed.) Expires: August, 2003 February, 2003 Analysis of Existing Quality of Service Signaling Protocols Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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. Distribution of this memo is unlimited. This Internet-Draft will expire in August, 2003. Copyright Notice Copyright (C) The Internet Society (2000). All Rights Reserved. All comments to this work should be directed to the NSIS mailing at nsis@ietf.org. Abstract This document presents a review of existing protocols for signalling the Quality of Service requirements of flows to nodes in an IP network. Protocols are reviewed independently and not compared against the NSIS requirements document nor to RSVP itself. The purpose is to learn from existing work and to avoid common misconceptions about the protocols. A further goal is to avoid to redesign ideas already implemented in another protocol. Manner et al Expires August 2003 [Page 1] Internet-Draft Analysis of QoS Signaling February 2003 Changes since -00 - More text on RFC2207, 2961, 3175, 3209, - Added [Berg02], [KoRe02], [LiPe02], RFC2379, 2380 and extensions proposed by ITU-T, OIF, 3GPP, - Re-wrote text on RSVP processing overhead, - Updated text on RSVP security, - Removed section on ITSUMO as it was mostly an architectural discussion, rather than a protocol review, - Updates various other parts of the document based on feedback, - Re-structured the document. TODO items - Evaluate the rest of the protocols in more depth - Add more protocols? Remove protocols? Table of Contents 1 Introduction ................................................. 3 2 The Resource Reservation Protocol ............................ 4 2.1 Extensions to RSVP ......................................... 5 2.2 Reservation functionality .................................. 11 2.3 Processing Overhead ........................................ 12 2.4 Bandwidth Consumption ...................................... 13 2.5 Mobility Support ........................................... 14 2.6 Security ................................................... 15 2.7 Deployment Issues .......................................... 15 2.8 Conclusions ................................................ 16 3 YESSIR ....................................................... 17 3.1 Reservation Functionality .................................. 17 3.2 Processing Overhead ........................................ 18 3.3 Bandwidth Consumption ...................................... 18 3.4 Mobility Support ........................................... 18 3.5 Security ................................................... 18 3.6 Deployment Issues .......................................... 18 3.7 Conclusions ................................................ 18 4 Boomerang .................................................... 18 4.1 Reservation Functionality .................................. 19 4.2 Processing Overhead ........................................ 19 4.3 Bandwidth Consumption ...................................... 19 4.4 Mobility Support ........................................... 19 4.5 Security ................................................... 19 4.6 Deployment Issues .......................................... 19 4.7 Conclusions ................................................ 20 5 INSIGNIA ..................................................... 20 6 BGRP ......................................................... 21 7 ST-II ........................................................ 21 8 Summary ...................................................... 21 9 Security Considerations ...................................... 22 10 Contributors ................................................ 22 11 Acknowledgment .............................................. 22 12 References .................................................. 22 13 Author's Addresses .......................................... 26 Manner et al Expires August 2003 [Page 2] Internet-Draft Analysis of QoS Signaling February 2003 1. Introduction The aim of this document is to present existing mature protocols for signalling the Quality of Service (QoS) requirements of flows to nodes in an IP network. The various protocols are reviewed independently and without comparing against the NSIS requirements document, because the protocols have already been designed before the work on present requirements was initialized. Neither do we want to make any comparison of protocols against RSVP because this would be of little value - all protocols have their own research backgrounds and targets and therefore do things differently. We also hope that the NSIS Working Group can learn from existing work and we can avoid common misconceptions about the protocols. A further goal is to avoid to redesign ideas already implemented in an existing protocol. There have been a number of historic attempts in delivering QoS or generic signaling into the Internet. In the early years, multicast was believed to be going to be popular to majority of communications, hence RSVP and earlier ST-II were designed in a way which is multicast-oriented. ST-II was developed as a reservation protocol for point-to-multipoint communication. However, since it is sender- initiated, it does not scale with the number of receivers in a multicast group. It is complex and since every sender needs to set up its own reservation, the total amount of reservation states is large. RSVP was then designed to provide support for multipoint-to- multipoint reservation setup in a more efficient way, however its complexity, scalability and ability to meet new requirements have been criticized. YESSIR [PaSc98] and Boomerang [FNM+99] are examples of protocols designed after RSVP. Both protocols were meant to be simpler than RSVP. YESSIR is an extension to RTCP, while Boomerang is used with ICMP. Previously, there has been a lot of work targeted at creating a new signalling protocol for resource control. Istvan Cselenyi suggested to request for QoSSIG BOF in IETF#47 (http://www-nrg.ee.lbl.gov/diff- serv-arch/msg05055.html), for identifying problems in QoS signaling, but failed. Some people argued, "in many ways, RSVP improved upon ST-2, and it did start out simpler, but resulting a design with complexity and scalability", while some others thought it is "new knowledge and requirements" that made RSVP insufficient (http://www- nrg.ee.lbl.gov/diff-serv-arch/msg05066.html), and there is no simpler way to handle the same problem as RSVP. Michael Welzl organized a special session "ABR to the Internet" in SCI 2001, and gathered some inputs for requesting an "ABR to the Internet" BOF in IETF#51, which was intended to introduce explicit rate feedback related mechanisms for the Internet (e2e, edge2edge) but failed because of "missing community interest" (http://www.tk.uni-linz.ac.at/~michael/abr-internet/). OPENSIG (http://comet.columbia.edu/opensig/) has been involved in the Internet signaling for years. Ping Pan initiated a SIGLITE Manner et al Expires August 2003 [Page 3] Internet-Draft Analysis of QoS Signaling February 2003 (http://www.cs.columbia.edu/~pingpan/projects/siglite.html) BOF mailing list to investigate light-weight Internet signaling. Finally, NSIS BOF was successful and the NSIS WG was formed. The most mature and original protocols are presented in their own sections and other QoS signalling protocols are presented in later subsections. 2. The Resource Reservation Protocol RSVP (the Resource Reservation Protocol) [RSVP] [RFC2205] [BEBH96] has evolved from ST-II to provide end-to-end QoS signaling services for application data streams. Hosts use RSVP to request a specific quality of service (QoS) from the network for particular application flows. Routers use RSVP to deliver QoS requests to all routers along the data path. RSVP also can maintain and refresh states for a requested QoS application flow. This section shortly reviews the RSVP basic model and its extensions. RSVP tries to be well-fit in the Integrated Services (IntServ) [RFC2210], [BEBH96] architecture with certain modularity and scalability. The design of the RSVP protocol distinguished itself by a number of fundamental ways, particularly, soft state management, two-pass signaling message exchanges, receiver-based resource reservation and separation of QoS signaling from routing. RSVP Signaling Model: The RSVP signaling model is based on a special handling of multicast. The sender of a multicast flow advertises the traffic characteristics periodically to the receivers via "Path" messages. On receipt of an advertisement, a receiver may generate a "Resv" message to reserve resources along the flow path from the sender. Receiver reservations may be heterogeneous. To accommodate the multipoint-to-multipoint multicast applications, RSVP was designed to support a vector of reservation attributes called the "style". A style describes whether all senders of a multicast group share a single reservation and which receiver is applied. The "Scope" object additionally provides the explicit list of senders. Soft State: Because the number of receivers in a multicast flow is likely to change, and the flow of delivery paths might change during the life of an application flow, RSVP takes a soft-state approach in its design, creating and removing the protocol states (Path and Resv states) in routers and hosts incrementally over time. RSVP sends periodic refresh messages (Path and Resv) to maintain its states and to recover from occasional lost messages. In the absence of refresh messages, the RSVP states automatically time out and are deleted. States may also be deleted explicitly by PathTear, PathErr with Path_State_Removed flag, or ResvTear Message. Two-pass Signaling Message Exchanges: The receiver in an application flow is responsible for requesting the desired QoS from the sender. To do this, the receiver issues an RSVP QoS request on behalf of the local application. The request propagates to all routers in reverse Manner et al Expires August 2003 [Page 4] Internet-Draft Analysis of QoS Signaling February 2003 direction of the data paths toward the sender. In this process, RSVP requests might be merged, resulting in a protocol that scales well when there are a large number of receivers. Receiver-based Resource Reservation: Receiver-initiation is critical for RSVP to setup multicast sessions with a large number of heterogeneous receivers. A receiver initiates a reservation request at a leaf of the multicast distribution tree, traveling toward the sender. Whenever a reservation is found to already exist in a node in the distribution tree, the new request will be merged with the existing reservation. This could result in fewer signalling operations for the RSVP nodes in the multicast tree close to the sender, but introduce a restriction to receiver-initiation. Separation of QoS Signaling from Routing: RSVP messages follow normal IP routing. RSVP is not a routing protocol, but rather is designed to operate with current and future unicast and multicast routing protocols. The routing protocols are responsible for choosing the routes to use to forward packets, and RSVP consults local routing tables to obtain routes. RSVP is responsible only for reservation setup along a data path. RFC 2205 defines 7 types of standard RSVP messages (Path, PathTear, PathErr, Resv, ResvErr, ResvTear, ResvConf) and a number of objects/object classes (SESSION, RSVP_HOP, INTEGRITY, TIME_VALUES, ERROR_SPEC, SCOPE List, STYLE, FLOWSPEC, FILTERSPEC, SENDER_TEMPLATE, IPv6 Flow-label SENDER_TEMPLATE, SENDER_TSPEC, ADSPEC, POLIY_DATA, RESV_CONFIRM). A detailed description of their definition and processing is given in [RFC2205]. 2.1. Extensions to RSVP Note: only IETF Standards Track RFCs and a limited set of other organizations' specifications are discussed below; informational RFCs (e.g., RFC2998) and work-in-progress I-Ds (e.g., proxy) are not covered here. RSVP can support IPsec on a per address, per protocol basis instead of on a per flow basis. [RFC2207] extends RSVP by using the IPSEC Security Parameter Index (SPI) in place of the UDP/TCP-like ports. This introduces a new FILTER_SPEC object, which contains the IPSEC SPI, and a new SESSION object. [RFC2750] specifies the format of POLICY_DATA objects and RSVP handling of policy events. RFC 2750 introduces objects which are interpreted only by policy aware nodes (PEPs) which interact with policy decision points (PDPs). Nodes which are unable to interpret the POLICY_DATA objects are called policy ignorant nodes (PINs). The content of the POLICY_DATA object itself is protected only between PEPs and therefore provides end-to-middle or middle-to-middle security. Manner et al Expires August 2003 [Page 5] Internet-Draft Analysis of QoS Signaling February 2003 [RFC2749] specifies the usage of COPS policy services in RSVP environments. [RFC2751] specifies a preemption priority policy element (PREEMPTION_PRI) for use by RSVP POLICY_DATA Object. [Hame02] describes how authorization provided by a separate protocol (such as SIP) can be reused with the help of an authorization token within RSVP. The token might therefore contain either the authorized information itself (e.g. QoS parameters) or a reference to those values. The token might be unprotected (which is strongly discouraged) or protected based on symmetric or asymmetric cryptography. Moreover, the document describes how to provide the host with encoded session authorization information as a POLICY_DATA object. [RFC2814] introduces an RSVP LAN_NHOP address object that keeps track of the next L3 hop as the PATH message traverses an L2 domain between two L3 entities (RSVP PHOP and NHOP nodes). Both layer-2 and layer-3 addresses are included in the LAN_NHOP; the RSVP_HOP_L2 object is used to include the Layer 2 address (L2ADDR) of the previous hop, complementing the L3 address information included in the RSVP_HOP object (RSVP_HOP_L3 address). To provide sufficient information for debugging or resource management, RSVP diagnostic messages (DREQ and DREP) are defined in [RFC2745] to collect and report RSVP state information along the path from a receiver to a specific sender. [RFC2746] describes an IP tunneling enhancement mechanism that allows RSVP to make reservations across all IP-in-IP tunnels, basically, by way of recursively applying RSVP over the tunnel portion of the path. [RFC2961] describes mechanisms to reduce processing overhead requirements of refresh messages, eliminate the state synchronization latency incurred when an RSVP message is lost and, refreshing state without the transmission of whole refresh messages. It defines the following objects: MESSAGE_ID, MESSAGE_ID_ACK, MESSAGE_ID_NACK, MESSAGE_ID LIST, MESSAGE_ID SRC_LIST and MESSAGE_ID MCAST_LIST objects. Three new RSVP message types are defined: 1) Bundle message, which consists of a bundle header followed by a body consisting one or more standard RSVP messages. Bundle messages help in scaling RSVP in reducing processing overhead and bandwidth consumption. 2) ACK message, which carries one or more MESSAGE_ID_ACK or MESSAGE_ID_NACK objects. ACK messages are sent between neighboring RSVP nodes to detect message loss and support reliable RSVP message delivery on a per hop basis. 3) Srefresh message, which carries one or more MESSAGE_ID LIST, MESSAGE_ID SRC_LIST and MESSAGE_ID MCAST_LIST objects. correspondent to Path and Resv messages that establish the states. Srefresh messages are used to refresh RSVP states without transmitting standard Path or Resv messages. Manner et al Expires August 2003 [Page 6] Internet-Draft Analysis of QoS Signaling February 2003 [RFC3175] allows to install one or more aggregated reservations in an aggregation region, thus the number of individual RSVP sessions can be reduced. The protocol type is swapped from RSVP to RSVP-E2E-IGNORE in E2E (standard) Path, PathTear and ResvConf messages when they enter the aggregation region, and swapped back when they leave. In addition to a new PathErr code (NEW_AGGREGATE_NEEDED), three new objects are introduced: 1) SESSION object, which contains two values: the IP Address of the aggregate session destination, and the DSCP that it will use on the E2E data the reservation contains. 2) SENDER_TEMPLATE object, which identifies the aggregating router for the aggregate reservation. 3) FILTER_SPEC object, which identifies the aggregating router for the aggregate reservation, and is syntactically identical to the SENDER_TEMPLATE object. From the perspective of RSVP signalling and the handling of data packets in the aggregation region, these cases are equivalent to the case of aggregating E2E RSVP reservations. The only difference is that E2E RSVP signalling does not take place and cannot therefore be used as a trigger, so some additional knowledge is required in setting up the aggregate reservation. RSVP-TE [RFC3209] specifies the extension to RSVP for establishing explicitly routed LSPs in MPLS networks using RSVP as a signaling protocol. RSVP-TE is intended for use by label switching routers (as well as hosts) to establish and maintain LSP-tunnels and to reserve network resources for such LSP-tunnels. RFC3209 defines a new Hello message (for rapid node failure detection), new C-Types (LSP_TUNNEL_IPv4 and LSP_TUNNEL_IPv6) for the SESSION (here a session is implicitly defined as the set of packets that are assigned the same MPLS label value at the originating node of an LSP-tunnel), SENDER_TEMPLATE, and FILTER_SPEC objects, and the following 5 new objects: 1) EXPLICIT_ROUTE object (ERO), which is incorporated into RSVP Path messages, encapsulating a concatenation of hops which constitutes the explicitly routed path. Using this object, the paths taken by label-switched RSVP-MPLS flows can be pre-determined, independent of conventional IP routing. 2) LABEL_REQUEST object. To establish an LSP tunnel, the sender can create a Path message with a LABEL_REQUEST object. A node that sends a LABEL_REQUEST object MUST be ready to accept and correctly process a LABEL object in the corresponding Resv messages. 3) LABEL object. Each node that receives a Resv message containing a LABEL object uses that label for outgoing traffic associated with this LSP tunnel. 4) SESSION_ATTRIBUTE object, which can be added to Path messages to Manner et al Expires August 2003 [Page 7] Internet-Draft Analysis of QoS Signaling February 2003 aid in session identification and diagnostics. Additional control information, such as setup and hold priorities, resource affinities and local-protection, are also included in this object. 5) RECORD_ROUTE object (RRO). The RECORD_ROUTE object may appear in both Path and Resv messages. It is used to collect detailed path information and is useful for loop detection and for diagnostics. Section 5 of RFC3270 further specifies the extensions to RSVP to establish LSPs supporting DiffServ in MPLS networks, introducing a new DIFFSERV Object (applicable in the Path messages) and using pre- configured or (e.g. RFC3270) signaled "EXP<-->PHB mapping". GMPLS RSVP-TE [Berg02] defines a Notify message (for general event notification), which may contain notifications being sent, with respect to each listed session, both upstream and downstream. Notify messages can be used together with Notify Request object for expedited notification of failures and other events to nodes responsible for restoring failed LSPs. A Notify message is sent without the router alert option. Besides, a number of new RSVP-TE (sub)objects are defined in GMPLS RSVP-TE for general uses of MPLS: (for label management:) - a Generalized Label Request Object; - Bandwidth Encoding carried in SENDER_TSPEC and FLOWSPEC objects, Generalized Label Object; - a Waveband Switching Object; - a Suggested Label Object; - a Label Set Object; (to support bidirectional LSP setup:) - an Upstream_Label object; (to support uni- and bi-directional Explicit Label Control:) - a Label ERO subobject; - a Label RRO subobject, which is included in RROs as described in [RFC3209]; (To Control Channel Separation:) - IF_ID RSVP_HOP objects (IPv4 & v6); - IF_ID ERROR_SPEC objects (IPv4 & v6); (to support rapid failure notification:) - a Acceptable Label Set object to support Notification on Label Error; - a Notify Request object, which may be inserted in Path or Resv messages to indicate where a notification of LSP failure is to be sent; (for fault handling:) - a Restart_Cap Object; (for administrative purposes:) - an Admin Status Object, which is used to notify each node along the path of the status of the LSP. Since RSVP-TE does not provide a way to indicate an unnumbered link in its Explicit Route and Record Route Objects, [KoRe02] specifies extensions to RSVP-TE to support (point-to-point) unnumbered links, namely, - an Unnumbered Interface ID Subobject, which is a new subobject of the Explicit Route Object (ERO) used to specify unnumbered links; - an LSP_TUNNEL_INTERFACE_ID Object, to allow the adjacent LSR to Manner et al Expires August 2003 [Page 8] Internet-Draft Analysis of QoS Signaling February 2003 form or use an identifier for the Forwarding Adjacency; - a new subobject of the Record Route Object, used to record that the LSP path traversed an unnumbered link. [LiPe02] proposes additional extensions to GMPLS RSVP-TE to support the capabilities of an Automatically Switched Optical Network (ASON, an architecture developed by ITU-T SG15). To support Soft Permanent Connection (SPC), it uses GENERALIZED_UNI object defined by [OIF- UNI-1.0] but introduces a new subtype: SPC_LABEL. In addition, a Call identifier (CALL_ID) object is used in logical call/connection separation, which are used together with a new Call capability (CALL_OPS) object for complete call/connection separation. Besides new error codes, 3 new C-types are defined for the SESSION object: UNI_IPv6 SESSION, ENNI_IPv4 SESSION and ENNI_IPv6 SESSION. Optical Internetworking Forum (OIF) UNI 1.0 signaling ([OIF-UNI-1.0]) supports [RFC2205, RFC2961, RFC3209, Berg02] in a limited way. 10 types of RSVP(-TE) messages are supported, but used in a slightly different way. For example, only FF style is supported; States are always deleted explicitly; a state timer expiration will not deleted the state, rather triggers a tear down message; any RSVP message must be dropped silently when fails security validation. Besides new error codes, a few new (sub)objects are introduced, including: - a new C-type for ACCEPTABLE_LABEL_SET [Berg02]; - a new C-type for ADMIN_STATUS [Berg02]; - a new C-type for LABEL_SET [Berg02]; - a new C-type for RECOVER_LABEL [Berg02]; - a new C-type for RESTART_CAP [Berg02]; - a new C-type for UPSTEAM_LABEL [Berg02]; - a UNI_IPv4_SESSION object, combined with LSP_TUNNEL_IPv4_SENDER_TEMPLATE object to uniquely identify a connection at a local UNI; - a GENERALIZED_LABEL_REQUEST object; - a GENERALIZED_UNI_ATTRIBUTES object, which contains one or more new SOURCE_TNA, DESTINATION_TNA, DIVERSITY, EGRESS_LABEL, SERVICE_LEVEL subobjects. EGRESS_LABEL can be used to specify either uni- or bi-directional connections; - a SONET/SDH_SENDER_TSPEC object. IETF ([RFC2379][RFC2380]) also defines RSVP over ATM implementation guidelines and requirements to interwork with the ATM (Forum) UNI 3.x/4.0. [RFC2380] states that the RSVP (control) messages and RSVP associated data packets must not be sent on the same VCs, and an explicit release of RSVP associated QoS VCs must be performed once the VC for forwarding RSVP control messages terminated. While a separate control VC is also possible for forwarding RSVP control messages, [RFC2379] recommends to create a best-effort short-cut (a short-cut is a point-to-point VC where the two end-points locate in different IP subnets) first (if not exist), which can allow setting up RSVP triggered VCs to use the best-effort end-point. For data flows, the subnet senders must establish all QoS VCs and the RSVP enabled subnet receiver must be able to accept incoming QoS VCs. RSVP must request the configurable inactivity timers of VCs be set to Manner et al Expires August 2003 [Page 9] Internet-Draft Analysis of QoS Signaling February 2003 "infinite", and if it is too complex to do this at the VC receiver, RSVP over ATM implementations are required not to use an inactivity timer to clear any received connections. In case of dynamic QoS, the replacement of VC should be done gracefully. ITU-T H.323 ([H.323]) recommends the IntServ resource reservation procedure using RSVP. The information whether an endpoint supports RSVP should be conveyed during the H.245 capability exchange phase, by setting appropriate qOSMode fields. If both endpoints are RSVP- capable, when opening an H.245 logical channel, a receiver port ID should be conveyed to the sender by the openLogicalChannelAck message. Only after that, can a "Path - Resv - ResvConf" process take place. The timer of waiting for ResvConf message will be set by the endpoint. The action in case of this timer expires, as well as RSVP reservation fails in any point during an H.323 call, is up to the vendor to take. Once a ResvConf message is sent or received, the endpoints should stop reservation timers and resume with the H.323 call procedures. Only explicit release of reservations are supported in [H.323]: before sending a closeLogicalChannel message for a stream, a sender should send a PathTear message if an RSVP session has been previous created for that stream; after receiving a closeLogicalChannel, a receiver should send a ResvTear similarly. Only the FF style is supported, even for point-to-multipoint calls. 3GPP TS 23.207 ([3GPP-TS23207]) specifies the QoS signaling procedure with policy control within the UMTS end-to-end QoS architecture. When using RSVP, the signaling source and/or destination are the User Equipments (UEs, devices that allow users access to network services) that locate in the Mobile Originating (MO) side and the Mobile Terminating (MT) side, and an RSVP signaling process can either trigger or be triggered by the (COPS) PDP Context establishment/modification process. The operation of refreshing states is not specified in [3GPP-TS23207]. If bidirectional reservation is needed, the RSVP signaling should be proceeded twice between the signaling source and the destination. The authorization token and flow identifier(s) in a policy data object should be included in the RSVP messages sent by the UE, if the token is available in the UE. When both RSVP and Service-based Local Policy are used, the Gateway GPRS Support Node (GGSN, the access point of the network) should use the policy information to decide whether to accept and forward Path/Resv messages. In summary, in various RSVP extensions, new message type ("RSVP-E2E- IGNORE") for RSVP Path, PathTear and ResvConf messages, at least 7 new RSVP message types (DREQ, DREP, Bundle, Ack, Srefresh, Hello, Notify) and numerous new RSVP objects (e.g., new objects for FILTER_SPEC, SESSION, and SENDER_TEMPLATE; LAN_NHOP RSVP_HOP_L2; MESSAGE_ID, MESSAGE_ID_ACK, MESSAGE_ID_NACK, MESSAGE_ID LIST, MESSAGE_ID SRC_LIST, MESSAGE_ID MCAST_LIST; ERO, RRO, LABEL_REQUEST, LABEL, SESSION_ATTRIBUTE; DIFFSERV; Generalized Label Request, Waveband Switching, Suggested Label, Label Set, Upstream_Label, Label ERO, Label RRO, IF_ID RSVP_HOP, IF_ID ERROR_SPEC, Acceptable Label Set, Notify Request, Restart_Cap, Admin Status; LSP_TUNNEL_INTERFACE_ID; GENERALIZED_UNI, SONET/SDH_SENDER_TSPEC; Manner et al Expires August 2003 [Page 10] Internet-Draft Analysis of QoS Signaling February 2003 various new subobjects) have been defined. o RFC2205 + policy_data (policy control + security) + RFC2961 (as a critical extension) being regarded as "De facto Standard RSVP". o Diagnostics messages, aggregation, (proxy,) DCLASS, operations over IP-in-IP tunnels, ATM, 802.x and ITU-T ASON networks have been defined. o RSVP-TE extends RSVP mainly by introducing Label Request, Explicit Routing, and Refresh Reduction (esp. local Acknowledgment). o GMPLS RSVP-TE extends RSVP-TE mainly by introducing new label/path types (Generalized Label Request TLV), new transport requirements (new TSPEC format) and bidirectional reservation (Upstream Label TLV). o OIF UNI-1.0 extends GMPLS RSVP-TE by adding new signaling objects used for optical networks. 2.2. Reservation functionality RSVP carries QoS signalling messages through the network, visiting each node along the data path. To make a resource reservation at a node, the RSVP module communicates with two local decision modules, admission control and policy control. Admission control determines whether the node has sufficient available resources to supply the requested QoS. Policy control provides authorization for the QoS request. If either check fails, the RSVP module returns an error notification to the application process that originated the request. If both checks succeed, the RSVP module sets parameters in a packet classifier and packet scheduler to obtain the desired QoS. The definition of the required resources is not part of the RSVP standard, but commonly the IntServ specifications for Controlled Load and Guaranteed Services are used. RSVP allows for unicast and multicast reservations. Various filtering rules may be used to identify flows belonging to a reservation - commonly the 5-tuple is used. RFC 2207 [RFC2207] specifies an RSVP extension to use the IPsec SPI (Security Parameter Index), in place of the UDP/TCP-like ports. The IPv6 Flow Label can also be used as a key in the filters. Furthermore, reservations may be distinct or shared by several senders. RFC2996 [RFC2996] introduces a DCLASS Object to carry Differentiated Services Code Points (DSCPs) in RSVP message objects. If the network element determines that the RSVP request is admissible to the DiffServ network, one or more DSCPs corresponding to the behavior aggregate are determined, and will be carried by the DCLASS Object added to the RESV message upstream toward the RSVP sender. For some applications, service parameters are specified by the Manner et al Expires August 2003 [Page 11] Internet-Draft Analysis of QoS Signaling February 2003 network, not by the application (e.g. ERP applications). The Null Service [RFC2997] allows applications to identify themselves to network QoS policy agents using RSVP signaling, but does not require them to specify resource requirements. QoS policy agents in the network respond by applying QoS policies appropriate for the application (as determined by the network administrator). The RSVP sender offers the new service type, 'Null Service Type' in the ADSPEC that is included with the PATH message. A new TSPEC corresponding to the new service type is added to the SENDER_TSPEC. In addition, the RSVP sender will typically include with the PATH message policy objects identifying the user, application and sub-flow, which will be used for network nodes to manage the correspondent traffic flow. 2.3. Processing Overhead By processing overhead we mean the amount of processing required to handle messages belonging to a reservation session. This is the processing required in addition to the processing needed for routing an (ordinary) IP packet. The processing overhead of RSVP originates from two major issues: 1) Complexity of the protocol elements. First, RSVP itself is per-flow based, thus the number of states is proportional to RSVP session number. Path and Resv states have to be maintained in each RSVP router for each session (and Path state also record the reverse route for the correspondent Resv message). Second, being receiver-initiated, RSVP optimizes various merging operations for multicast reservations while the Resv message is processed. To handle multicast, other mechanisms like reservation styles, scope object, and blockade state, are also required to present in the basic protocol. This not only adds sources of failures and errors, but also complicates the state machine. Third, the same RSVP signaling messages are not only used for maintaining the state, but also dealing with recovery of signaling message loss and discovery of route change. Thus, although protocol elements that represent the actual data (e.g., QoS parameters) specification are separated from signalling elements, the processing overhead needed for all RSVP messages is not marginal. Finally, the possible variations of the order and existence of objects increases the complexity of message parsing and internal message and state representation. (Editor's note, XF: ref. current discussion on layer-splitting? mainly regards to rethinking of RSVP if splitting different tasks into two layers. E.g., functions like congestion control and reliability may be challenged by current RSVP.) 2) Implementation-specific Overhead. There are two ways to send and receive RSVP messages, either as "raw" IP datagrams with protocol number 46, or as encapsulated UDP datagrams, the latter of which increase the efficiency of RSVP processing. Typical RSVP implementations are user-space daemons interacting with the kernel, hence state management, message sending and reception would affect the efficiency of the protocol processing. For Manner et al Expires August 2003 [Page 12] Internet-Draft Analysis of QoS Signaling February 2003 example, in the recent version of the implementation described in [Kars01], the relative execution costs for message sending/reception system calls "sendto", "select", "recvmsg" were 14-16%, 6-7%, 9-10%, individually, of the total execution cost; [Kars01] also found that state (memory) management can use up to 17-18% of the total execution cost, but it is possible to decrease that cost to 6-7%, if appropriate action is taken to replace the standard memory management with dedicated memory management for state information. RSVP/routing, RSVP/policy control, and RSVP/traffic control interfaces can also pose different overhead dependent on implementation. For example, the RSVP/routing overhead has been measured to be approximately 11-12% of the total execution cost [Kars01]. 2.4. Bandwidth Consumption By bandwidth consumption we mean the amount of bandwidth used to during the lifetime of a session: set up a reservation session, keep the session alive, and finally close it. RSVP messages are sent either to trigger a new reservation or refresh an existing reservation. In standard RSVP, Path/Resv messages are used for triggering and refreshing/recovering reservations, identically, which results in an increased size of refresh messages. The hop-by-hop refreshment may reduce the bandwidth consumption for RSVP, but could result in more sources of error/failure events. [RFC2961] presents a way to bundle standard RSVP messages and reduces the refreshment redundancy by Srefresh message. Thus, the signalling for an RSVP session uses for a session lasting n seconds: F(n) = (bP + bR) + ((n/Ri) * (bP + bR)) + bPt ,where bP IP payload size of Path message bR IP payload size of Resv message bPt IP payload size of Path Tear message Ri refresh interval For example, for a simple Controlled Load reservation without security and identification requirements the bandwidth consumption would be (bP is 172 bytes, bR is 92, and bPt is 44 bytes and Ri is 30 seconds): F(n): (172 + 92) + (n/30) * (172 + 92)) + 44 = 308 + (264n/30) bytes (Editor's note: Same values could be calculated for other protocols? Would these be of any use?) Manner et al Expires August 2003 [Page 13] Internet-Draft Analysis of QoS Signaling February 2003 2.5. Mobility Support Two issues raise concern when RSVP is used by a mobile node (MN): the flow identifier and reservation refresh. When an MN changes locations, it may need to change one of its assigned IP address. An MN may have an IP address by which it is reachable by nodes outside the access network and an IP address used to support local mobility management. Depending on the mobility management mechanism, a handover may force a change in any of these addresses. As a consequence the filters associated with a reservation may not identify the flow anymore and the resource reservation is ineffective, until a refresh with a new set of filters is initialized. The second issue is about following the movement of a mobile node. RFC2205 defines that Path messages can perform a local repair of reservation paths. When the route between the communicating end hosts changes, a Path message will set the state of the reservation on the new route and a subsequent Resv message will make the resource reservation. Therefore, by sending a Resv message a host cannot alone update the reservation, and thus perform a local repair, before a Path message has passed. Also, in order to provide fast adaptation to routing changes without the overhead of short refresh periods, the local routing protocol module can notify the RSVP process of route changes for particular destinations. The RSVP process should use this information to trigger a quick refresh of state for these destinations, using the new route (Chapter 3.6, RFC2205). However, not all local mobility protocols, or even Mobile IP, affect routing directly in routers, and thus mobility may not be noticed at RSVP routers. Thus, it may take a relatively long time before a reservation is refreshed following a handover. There have been several designs for extensions to RSVP to allow for more seamless mobility. One solution is presented in [MSK+03], which discusses in one section the coupling of RSVP and the mobility management mechanisms and proposes small extensions to RSVP to better handle the handover event, among other things. The extension allows the mobile host to request a Path for the downstream reservation when a handover has happened. Another example is Mobile RSVP (MRSVP) [MRSVP], which is an extension to standard RSVP. It is based on advance reservations, where neighboring access points keep resources reserved for mobile nodes moving to their coverage area. When a mobile node requests resources, the neighboring access points are checked too and a passive reservation is done around the mobile nodes current location. The problem with the various 'advance reservation' schemes is that they require topological information of the access network and usually advance knowledge of the handover event. Furthermore, the way the resource reserved in advance are used in the neighboring service areas is an open issue. A good overview of these different schemes can be found in [MA01]. Manner et al Expires August 2003 [Page 14] Internet-Draft Analysis of QoS Signaling February 2003 The interactions of RSVP and Mobile IP have been well documented in [Thom02]. 2.6. Security To allow a process on a system to securely identify the owner and the application of the communicating process (e.g. user id) and convey this information in RSVP messages (PATH or RESV) in a secure manner, [RFC2752] specifies the encoding of identities as RSVP POLICY_DATA Object. However, to provide iron-clad security protection cryptographic authentication combined with authorization has to be provided. Such a functionality is typically offered by authentication and key exchange protocols. Solely including a user identifier is insufficient. To provide hop-by-hop integrity and authentication of RSVP messages, RSVP message may contain an INTEGRITY object ([RFC2747]) using a keyed message digest. Since intermediate routers need to modify and process the content of the signaling message a hop-by-hop security architecture based on a chain-of-trust is used. However, with the different usage of RSVP as described throughout this document and with new requirements a re-evaluation of the original assumptions might be necessary. This provides protection against forgery and message modification. However this does not provide non-repudiation and protect against message deletion. In current RSVP security scheme, the two-way peer authentication and key management procedures are still missing. The security issues have been well analyzed in [Tsch02]. 2.7. Deployment Issues As a well-acknowledged protocol in the Internet, RSVP is being more and more expected to provide a more generic service for various signaling applications. However, RSVP messages were designed in a way to optimally support end-to-end QoS signaling. To meet with the increasing demand for a signaling protocol to also operate in host- to-edge and edge-to-edge ways, and serve for some other signaling purposes in addition to end-to-end QoS signaling, RSVP needs to be developed more flexible and applicable for more generic signaling. RSVP proxies [BEGD02] extends RSVP by being able to originates or receive the RSVP message on behalf of the end node(s), so that applications may still benefit from reservations that are not truly end-to-end. However, there are certainly scenarios where an application would want to explicitly convey its non-QoS purposed (as well as QoS) data from a host into the network, or from an ingress node to an egress node of an administrative domain, but it must do so without burdening the network with excess messaging overhead. Typical examples are an end host desiring a firewall service from its provider's network and MPLS label setup within an MPLS domain. Manner et al Expires August 2003 [Page 15] Internet-Draft Analysis of QoS Signaling February 2003 RSVP requires support from network routers and user space applications. Domains not supporting RSVP are traversed transparently. Unfortunately, like other IP options, RSVP messages implemented by way of IP alert option may result in themselves being dropped by some routers [FrJo02]. Although applications need to be built with RSVP libraries, one article presents a mechanism that would allow any host to benefit from RSVP mechanisms without applications awareness [MHS02]. A somewhat similar deployment benefit can be gained from the Localized RSVP [MSK+03]. The draft presents the concept of local RSVP-based reservation that can be used to trigger reservation within an access network alone. In those cases, an end-host may request QoS from its own access network without the co-operation of a correspondent node outside the access network - this would be especially helpful when the correspondent node is unaware of RSVP. A proxy node responds to the messages sent by the end host and enables both upstream and downstream reservations. Furthermore, the scheme allows for faster reservation repairs following a handover by triggering the proxy to assist in an RSVP local repair. Still, in end-hosts which are low in processing power and functionality, having an RSVP daemon running and taking care of the signalling may introduce unnecessary overhead. One article [Kars01] proposes to create a remote API so that the daemon would in fact be running on the end-host's default router and the end-host application would send its requests to that daemon. Another potential problem lies in the limited sized of signaled data due to the limitation of message size. RSVP message must fit entirely into a single non-fragmented IP datagram. Bundle messages [RFC2961] can aggregate multiple RSVP messages within a single PDU, but still only occupy one IP datagram (i.e., approximately 64K); if it exceeds the MTU, the datagram is fragmented by IP and reassembled at the recipient node. 2.8. Conclusions The design of RSVP was originally targeted at multicast applications. The result has been that the message processing within nodes is somewhat heavy, mainly due to flow merging. Still, merging rules should not appear in the specification as they are QoS-specific. RSVP has a comprehensive set of filtering rules (WF,FF, shared) and is not tied to certain QoS objects (RSVP is not tied to IntServ GS/CL specifications). Objects were designed to be modular, but Xspecs (TSPEC, etc) are more or less QoS-specific and should be more generalized; there is no clear layering/separation between the signaled data and signaling protocol. RSVP uses a soft state mechanism to maintain states and allows each node to define its own refresh timer. The protocol is also independent of underlying routing protocols. Still, in mobile Manner et al Expires August 2003 [Page 16] Internet-Draft Analysis of QoS Signaling February 2003 networks the movement of the mobile nodes may not properly trigger a reservation refresh for the new path and therefore a mobile node may be left without a reservation up to the length of the refresh timer. Furthermore, RSVP does not work properly with changing end-point identifiers, that is, if one of the IP addresses of a mobile node changes, the filters may not be able to identify the flow that had a reservation. From the security point of view, RSVP does provide the basic building blocks for deploying the protocol in various environments to protect its messages from forgery and modification. Hop-by-hop protection is provided. However, current RSVP security mechanism does not provide non-repudiation and protection against message deletion; the two-way peer authentication and key management procedures are still missing. Finally, since the publication of the RSVP standard, tens of extensions have emerged that allow for much wider deployment than RSVP was originally designed for, as for instance, the Subnet Bandwidth Manager, the NULL service type, aggregation, operation over tunneling and MPLS as well as diagnostic messages. Domains not supporting RSVP are traversed transparently by default. Unfortunately, like other IP options, RSVP messages implemented by way of IP alert option may result in themselves being dropped by some routers. Also, the maximal size of RSVP message is limited. 3. YESSIR YESSIR (YEt another Sender Session Internet Reservations) [PaSc98] is a resource reservation protocol that seeks to simplify the process of establishing reserved flows while preserving many unique features introduced in RSVP. Simplicity is measured in terms of control message processing, data packet processing, and user-level flexibility. Features such as robustness, advertising network service availability and resource sharing among multiple senders are also supported in the proposal. The proposed mechanism generates reservation requests by senders to reduce the processing overhead. It is built as an extension to the Real-Time Transport Control Protocol (RTCP), taking advantages of Real-Time Protocol (RTP). YESSIR also introduces a concept called partial reservation. 3.1. Reservation Functionality YESSIR was designed for one-way, sender-initiated end-to-end resource reservation. It also uses soft state to maintain states. It supports resource query (similar to RSVP diagnosis message), advertising (similar to RSVP ADSPEC), shared reservation, partial reservations and flow merging. To support multicast, YESSIR simplifies the reservation styles to Manner et al Expires August 2003 [Page 17] Internet-Draft Analysis of QoS Signaling February 2003 individual and shared reservation styles. Individual reservations are made separately for each sender, whereas shared reservations allocate resources that can be used by all senders in an RTP session. While RSVP supports shared reservation (SE and WF styles) from the receiver's direction, YESSIR handles the shared reservation style from the sender's direction, thus new receivers can re-use the existing reservation of the previous sender. 3.2. Processing Overhead In [PaSc00], it was proved that YESSIR one-pass reservation model has better performance and lower processing cost, comparing with a regular two-way signaling protocol. 3.3. Bandwidth Consumption The bandwidth consumption of YESSIR is somewhat lower than that of, for example, RSVP, because it does not require additional IP and transport headers. Bandwidth consumption is limited to the extension header size. 3.4. Mobility Support YESSIR does not have any particular support for mobility. 3.5. Security The security of YESSIR relies on RTP/RTCP security measures. 3.6. Deployment Issues YESSIR requires support in applications since it is an integral part of RTCP. Similarly, it requires network routers to inspect RTCP packets to identify reservation requests and refreshes. Routers unaware of YESSIR forward the RTCP packets transparently. 3.7. Conclusions 4. Boomerang Boomerang [FNM+99] is a another resource reservation protocol for IP networks. The protocol has only one message type and a single signaling loop for reservation set-up and tear-down, has no Manner et al Expires August 2003 [Page 18] Internet-Draft Analysis of QoS Signaling February 2003 requirements on the far end node, but, instead, concentrates the intelligence in the Initiating Node (IN). In addition, the Boomerang protocol allows for sender- or receiver- oriented reservations and resource query. Flows are identified with the common 5-tuple and the QoS can be specified with various means, eg. service class and bit rate. Boomerang messages are in the initial implementation transported in ICMP ECHO / REPLY messages. 4.1. Reservation Functionality Boomerang can only be used for unicast sessions, no support for multicast exists. The requested QoS can be specified with various methods and both ends of a communication session can make a reservation for their transmitted flow. 4.2. Processing Overhead The authors of Boomerang show in [FNS02] that the processing of the protocol is considerably lower than with the ISI RSVP daemon implementation. However, this is mainly due to the limited functionality provided by the protocol compared to RSVP. 4.3. Bandwidth Consumption Boomerang messages are quite short and consume a relatively low amount of link bandwidth. This is due to the limited functionality of the protocol, for example, no security specific information or policy-based interaction are provided. Being sender oriented, the bandwidth consumption mostly affects the downstream direction, from the sender to the receiver. 4.4. Mobility Support As Boomerang is sender oriented, there is no need to store backward information. This reduces the signalling required. The rest of the issues that were identified with RSVP apply with Boomerang. 4.5. Security No security mechanism is specified for Boomerang. 4.6. Deployment Issues The Boomerang protocol has similar deployment issues as any host- network-host protocol. It requires an implementation at both communicating nodes and in routers. Boomerang-unaware routers should be able to forward Boomerang messages transparently. Still, often Manner et al Expires August 2003 [Page 19] Internet-Draft Analysis of QoS Signaling February 2003 firewalls drop ICMP packets making the protocol useless. 4.7. Conclusions Boomerang seems to be a very lightweight protocol and efficient in its own scenarios. Still, the apparent low processing overhead and bandwidth consumption results from the limited functionality. No support for multicast or any security features are present which allows for a different functionality than RSVP, which the authors like to compare Boomerang to. 5. INSIGNIA INSIGNIA [LGZC00] has been developed at the Columbia University and is proposed as a very simple signaling mechanism for supporting QoS in mobile ad-hoc networks. It avoids the need for separate signaling by carrying the QoS signaling data along with the normal data in IP packets using IP packet header options. This approach, known as "in- band signaling" is proposed as more suitable in the rapidly changing environment of mobile networks since the signaled QoS information is not tied to a particular path. It also allows the flows to be rapidly established and, thus, is suitable for short lived and dynamic flows. INSIGNIA aims to minimize signaling by reducing the number of parameters that are provided to the network. It assumes that real- time flows may tolerate some loss, but are very delay sensitive so that the only QoS information needed is the required minimum and maximum bandwidth. The INSIGNIA protocol operates at the network layer and assumes that link status sensing and access schemes are provided by lower layer entities. The usefulness of the scheme depends upon the MAC layers but this is undefined so that INSIGNIA can run over any MAC layer. The protocol requires that each router maintains per-flow state. The INSIGNIA system implicitly supports mobility. A near-minimal amount of information is exchanged with the network. To achieve this, INSIGNIA makes many assumptions about the nature of traffic that a source will send. This may also simplify admission control and buffer allocation. The system basically assumes that "real-time" will be defined as a maximum delay and the user can simply request real-time service for a particular quantity of traffic. After handover, data that was transmitted to the old base station can be forwarded to the new base station so that no data loss should occur. However, there is no way to differentiate between re-routed and new traffic so priority cannot be given to handover traffic, for example. INSIGNIA, however, (completely) lacks a security framework and does not investigate how to secure signaled QoS data in ad-hoc network Manner et al Expires August 2003 [Page 20] Internet-Draft Analysis of QoS Signaling February 2003 where relatively weak trust or even no trust exists between the participating nodes. Hence authorization and charging especially might be a challenge. The security protection of in-band signaling is costly since the data delivery itself experiences increased latency if security processing is done hop-by-hop. Since the QoS signaling information is encoded into the flow label and end-to-end addressing is used, it is very difficult to provide security other than IPsec in tunnel mode. 6. BGRP Border Gateway Reservation Protocol (BGRP) [BGRP] is a signaling protocol for inter-domain aggregated resource reservation for unicast traffic. BGRP builds a sink tree for each of the stub domains. Each sink tree aggregates bandwidth reservations from all data sources in the network. BGRP maintains these aggregated reservations using soft state and relies on Differentiated Services for data forwarding. BGRP scales in terms of message processing load, state storage and bandwidth. Since backbone routers only maintain the sink tree information, the total number of reservations at each router scales linearly with the number of Internet domains. 7. ST-II ST-II [RFC1819] is an experimental resource reservation protocol intended to provide end-to-end real-time guarantees over an internet. It allows applications to build multi-destination simplex data streams with a desired quality of service. ST-II consists of two protocols: ST for the data transport and SCMP, the Stream Control Message Protocol, for all control functions. ST is simple and contains only a single PDU format that is designed for fast and efficient data forwarding in order to achieve low communication delays. SCMP packets are transferred within ST packets. ST-II has no built-in soft states, thus requires that the network be responsible for correctness. It is sender-initiated, and the overhead for ST-II to handle group membership dynamics is higher than RSVP [MESZ94]. ST-II does not provide security but RFC 1819 describes some objects related to charging. 8. Summary - Gather the good ideas from the protocols as a basis for the future designs - Note that extensive features and simplicity do not go hand-in-hand: "if you want features, be prepared to pay for the cost". Manner et al Expires August 2003 [Page 21] Internet-Draft Analysis of QoS Signaling February 2003 9. Security Considerations There are no security issues in this document. Individual protocols include different levels of security issues and those are highlighted in the relevant sections and references. 10. Contributors This document is part of the work done in the NSIS Working Group. The draft was initially written by Jukka Manner and Xiaoming Fu. Since the first version, Martin Karsten has provided text about the processing overhead of RSVP and Hannes Tschofenig has provided text about various security issues in the protocols. 11. Acknowledgment We would like to acknowledge Bob Braden and Vlora Rexhepi for their useful comments. 12. References [RFC1819] L. Delgrossi and L. Berger, Editors, Internet Stream Protocol Version 2 (ST2) Protocol Specification - Version ST2+, RFC 1819, August 1995. [MESZ94] D. Mitzel, D. Estrin, S. Shenker, and L. Zhang, An Architectural Comparison of ST-II and RSVP, INFOCOM'94. [BEBH96] Braden, R., Estrin, D., Berson, S., Herzog, S. and D. Zappala, "The Design of the RSVP Protocol", ISI Final Technical Report, Jul 1996. [RSVP] Zhang, L., Deering, S., Estrin, D. and D. Zappala, "RSVP: A New Resource Reservation Protocol", IEEE Network, Volume 7, Pages 8-18, Sep 1993. [RFC2205] Braden, R., Zhang, L., Berson, S., Herzog, S. and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, Sep 1997. [RFC2207] L. Berger and T. O'Malley, RSVP Extensions for IPSEC Data Flows, RFC 2207, September 1997. [RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated Services", RFC 2210, September 1997. [RFC2998] Bernet, Y., Yavatkar, R., Ford, P., Baker, F., Zhang, L., Speer, M., Braden, R. and B. Davie, "Integrated Services Operation over Diffserv Networks", RFC 2998, November 2000. [RFC2749] Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja, R. Manner et al Expires August 2003 [Page 22] Internet-Draft Analysis of QoS Signaling February 2003 and A. Sastry, COPS usage for RSVP, RFC 2749, January 2000. [RFC2750] Herzog, S., RSVP Extensions for Policy Control, RFC 2750, January 2000. [RFC2751] Herzog, S., Signaled Preemption Priority Policy Element, RFC 2751, January 2000. [RFC2752] Yadav, S., et al., "Identity Representation for RSVP", RFC 2752, January 2000. [RFC2747] Baker, F., Lindell, B. and M. Talwar, RSVP Cryptographic Authentication, RFC 2747, January 2000. [RFC2380] Berger, L., RSVP over ATM Implementation Requirements, RFC 2380, August 1998. [RFC2814] Yavatkar, R., Hoffman, D., Bernet, Y., Baker, F. and M. Speer, SBM (Subnet Bandwidth Manager): A Protocol for Admission Control over IEEE 802-style Networks, RFC 2814, May 2000. [RFC2745] Terzis, A., Braden B., S. Vincent, and L. Zhang, RSVP Diagnostic Messages, RFC 2745, January 2000. [RFC2746] Terzis, A., Krawczyk, J., Wroclawski, J. and L. Zhang, RSVP Operation Over IP Tunnels, RFC 2746, January 2000. [RFC2961] Berger, L., Gan, D., Swallow, G., Pan, P. and F. Tommasi, RSVP Refresh Reduction Extensions, RFC 2961, April 2001. [RFC2996] Bernet, Y., Format of the RSVP DCLASS Object, RFC 2996, November 2000. [RFC2997] Bernet, Y., Smiht, A. and B. Davie, Specification of the Null Service Type, RFC 2997, November 2000. [RFC3175] F. Baker, C. Iturralde, F. Le Faucheur, B. Davie, Aggregation of RSVP for IPv4 and IPv6 Reservations, RFC 3175, September 2001 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V. and G. Swallow, Extensions to RSVP for LSP Tunnels, RFC 3209, December 2001. [RFC3270] F. Le Faucheur (ed), L. Wu, and et al, Multi-Protocol Label Switching (MPLS) Support of Differentiated Services, RFC 3270, May 2002. [RFC2362] Estrin, D., Farinacci, D., Helmy, A., Thaler, D., Deering, S., Handley, M. and V. Jacobson, "Protocol Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification", RFC 2362, June, 1998. [Hame02] L-N. Hamer, B. Gage, B. Kosinski, and Hugh Shieh, Session Manner et al Expires August 2003 [Page 23] Internet-Draft Analysis of QoS Signaling February 2003 Authorization Policy Element, Internet Draft (in RFC editor queue), Nov 2002. (draft-ietf-rap-rsvp-authsession-05.txt) [Berg02] L. Berger (ed), Generalized MPLS Signaling - RSVP-TE Extensions, Internet draft (in RFC editor queue), Sept. 2002. (draft-ietf-mpls-generalized-rsvp-te-09.txt) [KoRe02] K. Kompella, Y. Rekhter, Signalling Unnumbered Links in RSVP-TE, Internet draft (in RFC editor queque), Oct. 2002. (draft-ietf-mpls-rsvp-unnum-08.txt) [LiPe02] Z. Lin, D. Pendarakis, Generalized MPLS (GMPLS) RSVP-TE Usage and Extensions for Automatically Switched Optical Network (ASON), Internet draft (in RFC editor queue), Oct. 2002. (draft-lin-ccamp-gmpls-ason-rsvpte-04.txt) [OIF-UNI-1.0] Optical Internetworking Forum (OIF) Implementation Agreement OIF-UNI-01.0, User Network Interface (UNI) 1.0 Signaling Specification, Oct. 2001. [RFC2379] L. Berger, RSVP over ATM Implementation Guidelines, RFC 2379 (BCP), Aug 1998. [RFC2380] L. Berger, RSVP over ATM Implementation Requirements, RFC 2380, Aug 1998. [H.323] ITU-T Recommendation H.323, Packet-based Multimedia Communications Systems, Nov. 2000. [H.245] ITU-T Recommendation H.245, Control Protocol for Multimedia Communication, July 2000. [Raja03] B. Rajagopalan, LDP and RSVP Extensions for Optical UNI Signaling, Internet draft (under IESG review), Jan. 2003. [3GPP-TS23207] 3GPP TS 23.207 V5.6.0, End-to-end Quality of Service (QoS) Concept and Architecture, Release 5, Dec. 2002. [BEGD02] Bernet, Y., Elfassy, N., Gai, S. and D. Dutt, "RSVP Proxy", draft-ietf-rsvp-proxy-03 (work in progress), Mar 2002. [Meer02] H. de Meer, et al. "Analysis of Existing QoS Solutions". Internet Draft. (draft-demeer-nsis-analysis-02.txt) [Tsch02] H. Tschofenig, "RSVP Security Properties". Internet Draft, Oct 2002. (draft-ietf-nsis-rsvp-sec-properties-00.txt) [Fu02] X. Fu, et al, "Analysis on RSVP Regarding Multicast". Internet Draft, Oct. 2002. (draft-fu-rsvp-multicast-analysis-01.txt) [Thom02] M. Thomas, "Analysis of Mobile IP and RSVP Interactions". Internet draft, Oct. 2002. (draft-thomas-nsis-rsvp-analysis-00.txt) Manner et al Expires August 2003 [Page 24] Internet-Draft Analysis of QoS Signaling February 2003 [RaNa98] B. Rajagopalan and R. Nair. "Multicast Routing with Resource Reservation". Journal of High Speed Networks, 7(2), pp. 113-139, July 1998. [FrJo02] Pierre Fransson and Andreas Jonsson, "The need for an alternative to IPv4-options", in RVK (RadioVetenskap och Kommunikation), Stockholm, Sweden, pp. 162-166, June 200. [MHS02] Yu-Ben Miao, Wen-Shyang Hwang, Ce-Kuen Shieh, "A transparent deployment method of RSVP-aware applications on UNIX". Computer Networks, 40 (2002), pp. 45-56. [FNS02] Gabor Feher, Krisztian Nemeth, Istvan Cselenyi, "Performance evaluation framework for IP resource reservation signalling". Performance Evaluation 48 (2002), pp. 131-156. [PaSc98] Ping Pan, Henning Schulzrinne, "YESSIR: A Simple Reservation Mechanism for the Internet". In the Proceedings of NOSSDAV, Cambridge, UK, July 1998. [PaSc00] P. Pan, and H. Schulzrinne, "Lightweight Resource Reservation Signaling: Design, Performance and Implementation", Bell Labs Technical Memorandum 10009669-03, July 2000. [KaSh01] Martin Karsten, Jens Schmitt, Ralf Steinmetz, "Implementation and Evaluation of the KOM RSVP Engine". IEEE Infocom 2001. [Kars01] Martin Karsten, "Experimental Extensions to RSVP -- Remote Client and One-Pass Signalling". IWQoS 2001, Karlsruhe, Germany, June 2001. [LGZC00] S. Lee, A. Gahng-Seop, X. Zhang, A. Campbell,"INSIGNIA: An IP-Based Quality of Service Framework for Mobile Ad Hoc Networks". Journal of Parallel and Distributed Computing (Academic Press), Special issue on Wireless and Mobile Computing and Communications}, Vol. 60, Number 4, April, 2000, pp. 374-406. [FNM+99] G. Feher, K. Nemeth, M. Maliosz, I. Cselenyi, J. Bergkvist, D. Ahlard, T. Engborg, "Boomerang A Simple Protocol for Resource Reservation in IP Networks", IEEE RTAS, 1999. [MSK+03] J. Manner, T. Suihko, M. Kojo, M. Liljeberg, K. Raatikainen, "Localized RSVP". Internet Draft, January 2003. (draft-manner-lrsvp-01.txt) [BGRP] P. Pan, E, Hahne, and H. Schulzrinne, "BGRP: A Tree-Based Aggregation Protocol for Inter-domain Reservations", Journal of Communications and Networks, Vol. 2, No. 2, June 2000, pp. 157-167. [MRSVP] A. Talukdar, B. Badrinath, and A. Acharya, MRSVP: A Resource Reservation Protocol for an Integrated Services Network with Mobile Hosts, Wireless Networks, vol. 7, no. 1, pp. 5-19. 2001. Manner et al Expires August 2003 [Page 25] Internet-Draft Analysis of QoS Signaling February 2003 [MA01] Bobgkyo Moon, Hamid Aghvami, "RSVP Extensions for Real-Time Services in Wireless Mobile Networks". IEEE Communications Magazine, December 2001, pp. 52-59. 13. Author's Addresses Questions about this document may be directed to: Jukka Manner Department of Computer Science University of Helsinki P.O. Box 26 (Teollisuuskatu 23) FIN-00014 HELSINKI Finland Voice: +358-9-191-44210 Fax: +358-9-191-44441 E-Mail: jmanner@cs.helsinki.fi Xiaoming Fu Institute for Informatics Georg-August-University of Goettingen Lotzestrasse 16-18 37083 Goettingen Germany Voice: +49-551-39-14411 Fax: +49-551-39-14403 E-Mail: fu@cs.uni-goettingen.de Full Copyright Statement Copyright (C) The Internet Society (2001). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING Manner et al Expires August 2003 [Page 26] Internet-Draft Analysis of QoS Signaling February 2003 TASK FORCE DISCLAIMS 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. Manner et al Expires August 2003 [Page 27]