Y. Bernet, Microsoft
                                                      R. Yavatkar, Intel
                                                      P. Ford, Microsoft
                                                         F. Baker, Cisco
                                                          L. Zhang, UCLA
                                              M. Speer, Sun Microsystems
                                                          R. Braden, ISI
                                                         B. Davie, Cisco
Internet Draft
Expires: September, December, 1999
Document: draft-ietf-issll-diffserv-rsvp-01.txt             March, draft-ietf-issll-diffserv-rsvp-02.txt              June, 1999

          Interoperation of RSVP/Intserv and

          Integrated Services Operation Over Diffserv Networks

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
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      The list of current Internet-Drafts can be accessed at
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1. Abstract

   RSVP/Integrated Services and Differentiated

   The Integrated Services provide
   complementary approaches to architecture provides a means for the problem
   delivery of providing end-to-end QoS
   in to applications over heterogeneous
   networks. To support this end-to-end model, the Internet.  These approaches Intserv architecture
   must be able to coexist and
   effectively inter-operate. supported over a wide variety of different types of network
   elements. In this context, a network that supports Differentiated
   Services (Diffserv) may be viewed as a network element in the total
   end-to-end path. This document describes a framework by which the two approaches inter-operate to provide end-to-end QoS for
   quantitative applications (applications for which QoS requirements
   are readily quantifiable, and which rely on these QoS requirements
   to function properly).
   Integrated Services may be supported over Diffserv networks.

2. Introduction

   Work on QoS-enabled IP networks has led to two distinct approaches:
   the Integrated Services architecture (intserv)[12] (intserv)[10] and its
   accompanying signaling protocol, RSVP [1], vs. and the Differentiated
   Services architecture (diffserv)[10].

2.1 RSVP/Intserv (diffserv)[8]. This document describes ways in

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                      Use of RSVP with

     Integrated Services Operation Over Diffserv           March, Networks   June, 1999

   RSVP is

   which a signaling protocol that applications may use Diffserv network can be used in the context of the Intserv
   architecture to request
   resources from support the network. delivery of end-to-end QOS.

2.1 Integrated Services Architecture

   The network responds by explicitly
   admitting or rejecting RSVP requests. Certain applications that have
   quantifiable resource requirements express these requirements using
   intserv parameters. It is important to emphasize that RSVP and
   intserv are separable; RSVP is integrated services architecture defined a signaling protocol. Intserv set of extensions to
   the traditional best effort model of the Internet with the goal of
   allowing end-to-end QOS to be provided to applications. One of the
   key components of the architecture is a set of models for expressing service types, quantifying resource
   requirements and for determining definitions;
   the availability current set of services consists of the requested
   resources at relevant network elements (admission control). controlled load and
   guaranteed services. The current prevailing model of RSVP usage architecture assumes that some explicit
   setup mechanism is based on a combined
   RSVP/intserv architecture. In this model, RSVP signals per-flow
   resource requirements used to convey information to routers so that
   they can provide requested services to flows that require them.
   While RSVP is the most widely known example of such a setup
   mechanism, the intserv architecture is designed to accommodate other
   mechanisms.

   Intserv services are implemented by _network elements_. While it is
   common for network elements to be individual nodes such as routers
   or links, more complex entities, such as ATM _clouds_ or 802.3
   networks may also function as network elements. As discussed in more
   detail below, a Diffserv network (or _cloud_) may be viewed as a
   network element within a larger intserv network.

2.3 RSVP

   RSVP is a signaling protocol that applications may use to request
   resources from the network. The network responds by explicitly
   admitting or rejecting RSVP requests. Certain applications that have
   quantifiable resource requirements express these requirements using
   intserv parameters as defined in the appropriate intserv service
   specification. As noted above, RSVP and intserv are separable. RSVP
   is a signaling protocol which may carry intserv information. Intserv
   defines the models for expressing service types, quantifying
   resource requirements and for determining the availability of the
   requested resources at relevant network elements (admission
   control).

   The current prevailing model of RSVP usage is based on a combined
   RSVP/intserv architecture. In this model, RSVP signals per-flow
   resource requirements to network elements, using Intserv parameters.
   These network elements apply Intserv admission control to signaled
   requests. In addition, traffic control mechanisms on the network
   element are configured to ensure that each admitted flow receives
   the service requested in strict isolation from other traffic. To
   this end, RSVP signaling configures 'MF' [10] microflow (MF) [8] packet
   classifiers in intserv capable routers along the path of the traffic
   flow. These classifiers enable per-flow classification of packets
   based on IP addresses and port numbers.

   The following factors have impeded deployment of RSVP (and the RSVP/Intserv
   architecture
   intserv architecture) in the Internet at large:

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   1. The use of per-flow state and per-flow processing raises
      scalability concerns for large networks.

   2. Only a small number of hosts currently generate RSVP signaling.
      While this number is expected to grow dramatically, many
      applications may never generate RSVP signaling.

   3. The necessary policy control mechanisms -- access control,
      authentication, and accounting -- are not available.

2.2 _- have only recently become
      available [17].

2.4 Diffserv

   The market is pushing for immediate deployment of a QoS solution
   that addresses the needs of the Internet as well as enterprise
   networks. This push led to the development of diffserv. In contrast
   to the per-flow orientation of RSVP/intserv, RSVP, diffserv networks classify
   packets into one of a small number of aggregated flows or 'classes',
   based on the diffserv codepoint (DSCP) in the packet's IP header.
   This is known as 'BA' behavior aggregate (BA) classification [10]. [8]. At each
   diffserv router, packets are subjected to a 'per-hop behaviour'
   (PHB), which is invoked by the DSCP. The primary benefit of diffserv
   is its scalability. Diffserv eliminates the need for per-flow state
   and per-flow processing and therefore scales well to large networks.

2.3 Complementary

2.5 Roles of RSVP/Intserv Intserv, RSVP and Diffserv

   We view RSVP/intserv intserv, RSVP and diffserv as complementary technologies in
   the pursuit of end-to-end QoS. Together, these mechanisms can
   facilitate deployment of applications such as IP-telephony, video-

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                      Use of RSVP with Diffserv           March, 1999
   on-demand, and various non-multimedia mission-critical applications.
   RSVP/intserv
   Intserv enables hosts to request per-flow, quantifiable resources,
   along end-to-end data paths and to obtain feedback regarding
   admissibility of these requests. Diffserv enables scalability across
   large networks.

2.3

2.6 Components of RSVP/intserv Intserv, RSVP and Diffserv

   Before proceeding, it is helpful to identify the following
   components of the QoS technologies described:

   RSVP signaling - This term refers to the standard RSVP per-flow signaling
   protocol. RSVP signaling is used by hosts to signal per-
   flow application
   resource requirements to the network (and to each other). Network
   elements use RSVP signaling to return an admission control decision
   to hosts. RSVP signaling may or may not carry intserv parameters.
   Admission control at a network element may or may not be based on
   the intserv model.

   RSVP/Intserv - This term is used to refer to the prevailing model of
   RSVP usage which includes RSVP signaling with intserv parameters,
   intserv admission control and per-flow traffic control at network
   elements.

   MF traffic control

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   MF traffic control - This term refers to traffic control which is
   applied independently to individual traffic flows and therefore
   requires recognizing individual traffic flows via MF classification.

   Aggregate traffic control - This term refers to traffic control
   which is applied collectively to sets of traffic flows. These sets
   of traffic flows are recognized based on BA (DSCP) classification.
   In this draft, we use the terms 'aggregate traffic control' and
   'diffserv' interchangeably.

   We will refer

   Aggregate RSVP. While the existing definition of RSVP supports only
   per-flow reservations, extensions to RSVP/intserv regions RSVP are being developed to
   enable RSVP reservations to be made for aggregated traffic, i.e.
   sets of the network and diffserv
   regions flows that may be recognized by BA classification. This use
   of RSVP may be useful in controlling the network. RSVP/intserv regions are those regions allocation of bandwidth in
   Diffserv networks.

   Per-flow RSVP. The conventional usage of RSVP to perform resource
   reservations for individual microflows.

   RSVP/Intserv - This term is used to refer to the prevailing model of
   RSVP usage which both includes RSVP signaling and MF traffic with intserv parameters,
   intserv admission control are supported.
   These regions include hosts and network elements that are
   RSVP/intserv capable. (RSVP/intserv regions are not precluded from
   supporting aggregate per-flow traffic control as well as MF traffic control). at network
   elements.

   Diffserv regions are those regions in Region. A set of contiguous routers which aggregate support BA
   classification and traffic
   control is supported.

2.4 The Framework

   In control. While such a region may also
   support MF classification, the framework we present, end-to-end, quantitative QoS goal of this document is
   provided by coupling RSVP/Intserv regions at to describe
   how such a region may be used in delivery of end-to-end QOS when
   only BA classification is performed inside the periphery diffserv region.

   Intserv Region. The portions of the network with outside the diffserv regions
   region. We assume MF classification and traffic control is available
   in such regions. Such a region may also offer BA classification and
   traffic control.

   Note that, for the core purposes of this document, the network. The
   diffserv regions may, but key distinction
   between an Intserv and a Diffserv region is the type of
   classification and traffic control that is used for the delivery of
   end-to-end QOS for a particular application. Thus, while it may not
   be possible to identify a certain region as _purely Diffserv_ or
   _purely Intserv_ with respect to all traffic flowing through the
   region, it is possible to make these distinctions from the
   perspective of the treatment of traffic from a single application.

2.7 The Framework

   In the framework we present, end-to-end, quantitative QoS is
   provided by coupling Intserv regions at the periphery of the network
   with diffserv regions in the core of the network. The diffserv
   regions may, but are not required to, participate in the end-to-end RSVP

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   signaling for the purpose of optimizing resource allocation and
   supporting admission control.

   From the perspective of RSVP/intserv, Intserv, diffserv regions of the network are
   treated as virtual links connecting RSVP/Intserv Intserv capable

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                      Use of RSVP with Diffserv           March, 1999 routers or hosts
   (much as an 802.1p network region is treated as a virtual link in
   [5]). Within the diffserv regions of the network routers implement
   specific PHBs (aggregate traffic control). We use
   RSVP to apply admission control to each PHB in The total amount of
   traffic that is admitted into the diffserv region. region that will receive
   a certain PHB may be limited by policing at the edge.  As a result
   we expect that the diffserv regions of the network will be able to extend
   support the intserv style services requested from the periphery. As
   such, we often refer to the RSVP/intserv Intserv network regions as 'customers'
   of the diffserv network regions.

   In our framework, we address the inter-operability between the
   RSVP/intserv
   Intserv regions of the network and the diffserv regions of the
   network. Our goal is to enable seamless inter-operation. As a
   result, the network administrator is free to choose which regions of
   the network act as RSVP/intserv Intserv regions and which act as diffserv
   regions. In one extreme the diffserv region is pushed all the way to
   the periphery, with hosts alone comprising the RSVP/intserv Intserv regions of
   the network. In the other extreme, RSVP/intserv Intserv is pushed all the way to
   the core, with no diffserv region.

2.5

2.8 Contents

   In section 3 we discuss the benefits that can be realized by using
   RSVP/intserv together with
   the aggregate traffic control provided by diffserv network regions. regions
   in the broader context of the Intserv architecture. In section 4, we
   present the framework and the reference network. Section 5 details
   two possible realizations of the framework. Section 6 discusses the
   implications of the framework for diffserv. Appendix A contains a
   list of some important terms used in this document.

   Though the primary goal of this draft is to describe a framework
   for inter-operation of RSVP/intserv Intserv network regions and diffserv network
   regions, the draft currently does not address the issues specific to
   IP multicast flows.

3. Benefits of Using RSVP/intserv Intserv with Diffserv

   The primary benefit of diffserv aggregate traffic control is its
   scalability. In this section, we discuss the benefits that
   interoperation with RSVP/intserv Intserv can bring to a diffserv network region.
   Note that this discussion is in the context of servicing
   quantitative QoS applications specifically. By this we mean those
   applications that are able to quantify their traffic and QoS
   requirements.

3.1 Resource Based Admission Control

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   In RSVP/Intserv Intserv networks, quantitative QoS applications use RSVP an explicit
   setup mechanism (e.g. RSVP) to request resources from the network.
   The network may accept or reject these requests in response. This is
   'explicit admission control'. Explicit admission control helps to
   assure that network resources are optimally used. To further
   understand this issue, consider a diffserv network region providing
   only aggregate traffic control with no signaling. In the diffserv
   network region, admission control is applied implicitly by
   provisioning policing parameters at network elements. For example, a
   network element at the ingress to a

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                      Use of RSVP with Diffserv           March, 1999 diffserv network region could be
   provisioned to accept only 50 Kbps of traffic for the EF DSCP.

   While such implicit admission control does protect the network to
   some degree, it can be quite ineffective. For example, consider that
   there may be 10 IP telephony sessions originating outside the
   diffserv network region, each requiring 10 Kbps of EF service from
   the diffserv network region. Since the network element protecting
   the diffserv network region is provisioned to accept only 50 Kbps of
   traffic for the EF DSCP, it will discard half the offered traffic.
   This traffic will be discarded from the aggregation of traffic
   marked EF, with no regard to the microflow from which it originated.
   As a result, it is likely that of the ten IP telephony sessions,
   none will obtain satisfactory service when in fact, there are
   sufficient resources available in the diffserv network region to
   satisfy five sessions.

   In the case of explicit admission control, the network will signal
   rejection in response to requests for resources that would exceed
   the 50 Kbps limit. As a result, upstream network elements (including
   originating hosts) and applications will have the information they
   require to take corrective action. The application might respond by
   refraining from transmitting, or by requesting admission for a
   lesser traffic profile. The host operating system might respond by
   marking the application's traffic for the DSCP that corresponds to
   best-effort service. Upstream network elements might respond by re-
   marking packets on the rejected flow to a lower service level. In
   some cases, it may be possible to reroute traffic over alternate
   paths or even alternate networks (e.g. the PSTN for voice calls). In
   any case, the integrity of those flows that were admitted would be
   preserved, at the expense of the flows that were not admitted. Thus,
   by appointing an RSVP conversant Intserv-conversant admission control agent for the
   diffserv region of the network it is possible to enhance the service
   that the network can provide to quantitative QoS applications.

3.2 Policy Based Admission Control

   In an RSVP/intserv network region, regions where RSVP is used, resource requests can be
   intercepted by RSVP aware RSVP-aware network elements and can be reviewed
   against policies stored in policy databases. These resource requests
   securely identify the user and the application for which the
   resources are requested. Consequently, the network element is able
   to consider per-user and/or per-application policy when deciding

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   whether or not to admit a resource request. So, in addition to
   optimizing the use of resources in a diffserv network region (as
   discussed in 3.1) RSVP conversant admission control agents can be
   used to apply specific customer policies in determining the specific
   customer traffic flows entitled to use the diffserv network region's
   resources. Customer policies can be used to allocate resources to
   specific users and/or applications.

   By comparison, in diffserv network regions without per-flow RSVP signaling,
   policies are typically applied based on the diffserv customer
   network from which traffic originates, not on the originating user
   or application within the customer network.

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                      Use of RSVP with Diffserv           March, 1999

3.3 Assistance in Traffic Identification/Classification

   Within diffserv network regions, traffic is allotted service based
   on the DSCP marked in each packet's IP header. Thus, in order to
   obtain a particular level of service within the diffserv network
   region, it is necessary to effect the marking of the correct DSCP in
   packet headers. There are two mechanisms for doing so, host marking
   and router marking. In the case of host marking, the host operating
   system marks the DSCP in transmitted packets. In the case of router
   marking, routers in the network are configured to identify specific
   traffic (based (typically based on MF classification) and to mark the DSCP
   as packets transit the router. There are advantages and
   disadvantages to each scheme. Regardless of the scheme used, RSVP
   explicit signaling offers significant benefits.

3.3.1 Host Marking

   In the case of host marking, the host operating system marks the
   DSCP in transmitted packets. This approach has the benefit of
   shifting per-flow classification and marking to the edge of the
   network, where it scales best. It also enables the host to make
   decisions regarding the mark (and hence the relative priority that
   is requested) that is appropriate for each
   transmitted packet and hence the relative importance attached to
   each packet. The host is generally better equipped to make this
   decision than the network. Furthermore, if IPSEC encryption is used,
   the host may be the only device in the network that is able to make
   a meaningful determination of the appropriate marking for each
   packet.

   Host marking requires that the host be aware of the interpretation
   of DSCPs by the network. This information can be configured into
   each host. However, such configuration imposes a management burden.
   Alternatively, RSVP/intserv hosts can use RSVP an explicit signaling protocol such as
   RSVP to query the network to obtain a suitable DSCP or set of DSCPs
   to apply to packets for which a mapping from certain intserv service type to DSCP. This is has been
   requested. An example of how this can be achieved via the RSVP DCLASS object [17] and is explained later described in
   this draft.
   [14].

3.3.2 Router Marking

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   In the case of router marking, MF classification criteria must be
   configured in the router. This may be done dynamically, by request
   from the host operating system, or statically via manual
   configuration or via automated scripts.

   There are significant difficulties in doing so statically.
   Typically, it is desirable to allot service to traffic based on the
   application and/or user originating the traffic. At times it is
   possible to identify packets associated with a specific application
   by the IP port numbers in the headers. It may also be possible to
   identify packets originating from a specific user by the source IP
   address. However, such classification criteria may change
   frequently. Users may be assigned different IP addresses by DHCP.
   Applications may use transient ports. To further complicate matters,
   multiple users may share an IP address. These factors make it very
   difficult to manage static configuration of the classification
   information required to mark traffic in routers.

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                      Use of RSVP with Diffserv           March, 1999

   An attractive alternative to static configuration is to allow host
   operating systems to signal classification criteria to the router on
   behalf of users and applications. As we will show later in this
   draft, RSVP signaling is ideally suited for this task. In addition
   to enabling dynamic and accurate updating of MF classification
   criteria, RSVP signaling enables classification of IPSec [16] IPSEC [13]
   packets (by use of the SPI) which would otherwise be unrecognizable.

3.4 Traffic Conditioning

   Those

   Intserv-capable network elements that do provide RSVP/intserv support will are able to condition traffic at a
   per-flow granularity, by some combination of shaping and/or
   policing. Pre-conditioning traffic in this manner before it is
   submitted to the diffserv region of the network is beneficial. In
   particular, it enhances the ability of the diffserv region of the
   network to provide quantitative services using aggregate traffic
   control.

4. The Framework

   In the general framework we envision an Internet in which hosts use
   RSVP/intserv to request reservations for specific services from the
   network.
   Integrated Services architecture is used to deliver end-to-end QOS
   to applications. The network includes some combination of RSVP/intserv Intserv
   regions (in which MF classification and per-flow traffic control is
   applied) and diffserv regions (in which aggregate traffic control is
   applied). Individual routers may or may not participate in RSVP
   signaling regardless of the type of network region in which they
   reside.

   We will consider two specific realizations of the framework. In the
   first, resources within the diffserv regions of the network are
   statically provisioned and these regions include no RSVP aware
   devices. In the second, resources within the diffserv region of the

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   network are dynamically provisioned and select devices within the
   diffserv network regions participate in RSVP signaling.

4.1 Reference Network

   The two realizations of the framework will be discussed in the
   context of the following reference network:

            /        \       /              \       /        \
           /          \     /                \     /          \
    |---| |        |---|   |---|          |---|   |---|        | |---|
    |Tx |-|        |ER1|---|BR1|          |BR2|---|ER2|        |-|Rx |
    |---| |        |-- |   |---|          |---|   |---|        | |---|
           \          /     \                /     \          /
            \______  /       \___ _________ /       \__ _____/

    RSVP/Intserv

          Intserv region      Diffserv region      RSVP/Intserv       Intserv region

                 Figure 1: Sample Network Configuration

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                      Use of RSVP with Diffserv           March, 1999

   The reference network includes a diffserv region interconnecting two
   RSVP/intserv
   Intserv regions. The diffserv region contains a mesh of routers, at
   least some of which provide aggregate traffic control. The RSVP/intserv Intserv
   regions contain meshes of routers and attached hosts, at least some
   of which are RSVP/intserv capable. support the Integrated Services architecture.

   In the interest of simplicity we consider a single QoS sender, Tx in
   one of the RSVP/intserv Intserv network regions and a single QoS receiver, Rx in
   the other. The edge routers (ER1, ER2) within the RSVP/intserv Intserv regions
   interface to the border routers (BR1, BR1) within the diffserv
   regions.

   From an economic viewpoint, we may consider that the diffserv region
   sells service to the RSVP/intserv Intserv regions, which provide service to
   hosts.  Thus, we may think of the RSVP/intserv Intserv regions as customers of
   the diffserv region.  In the following, we use the term 'customer'
   for the RSVP/intserv Intserv regions.

4.1.1 Components Note that the boundaries of the Reference Network regions may
   or may not align with administrative domain boundaries, and that a
   single region might contain multiple administrative domains.

   We now define the major components of the reference network.

4.1.1.1

4.1.1 Hosts

   Both

   We assume that both sending and receiving hosts use RSVP/intserv RSVP to
   communicate the quantitative QoS requirements of QoS-aware
   applications running on the host. Typically, a QoS process within the host operating system In principle, other mechanisms may
   be used to establish resource reservations in an Intserv region, but
   RSVP is clearly the prevalent mechanism for this purpose.

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   Typically, a QoS process within the host operating system generates
   RSVP signaling on behalf of applications. This process may also
   invoke local traffic control.

   In this example,

   As discussed above, traffic control in the host marks may mark the DSCP in
   transmitted packets, and it shapes shape transmitted traffic to the
   requirements of the intserv service in use. In alternate
   realizations of the framework, Alternatively, the
   first-hop router within the
   RSVP/intserv Intserv network regions may provide
   these traffic control functions.

4.1.1.2

4.1.2 End-to-End RSVP Signaling

   We assume that RSVP signaling messages travel end-to-end between
   hosts Tx and Rx to support RSVP/intserv reservations in the
   RSVP/intserv Intserv
   network regions.  We require that these end-to-end RSVP messages are
   carried across the diffserv region. Depending on the specific
   realization of the framework, these messages may be processed by
   none, some or all of the routers in the diffserv region.

4.1.1.3

4.1.3 Edge Routers

   ER1 and ER2 are edge routers, residing in the RSVP/intserv Intserv network
   regions. The functionality of the edge routers varies depending on
   the specific realization of the framework. In the case in which the
   diffserv network region is RSVP unaware, edge routers act as
   admission control agents to the diffserv network. They process

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                      Use of RSVP with Diffserv           March, 1999
   signaling messages from both Tx and Rx, and apply admission control
   based on resource availability within the diffserv network region
   and on customer defined policy. In the case in which the diffserv
   network region is RSVP aware, the edge routers apply admission
   control based on local resource availability and on customer defined
   policy. In this case, the border routers act as the admission
   control agent to the diffserv network region.

   We will later describe the functionality of the edge routers in
   greater depth for each of the two realizations of the framework.

4.1.1.4

4.1.4 Border Routers

   BR1 and BR2 are border routers, residing in the diffserv network
   region. The functionality of the border routers varies depending on
   the specific realization of the framework. In the case in which the
   diffserv network region is RSVP/intserv unaware, RSVP-unaware, these routers act as pure
   diffserv routers. As such, their sole responsibility is to police
   submitted traffic based on the service level specified in the DSCP
   and the agreement negotiated with the customer (aggregate traffic
   control). In the case in which the diffserv network region is RSVP/intserv RSVP-
   aware, the border routers participate in RSVP signaling and act as
   admission control agents for the diffserv network region.

   We will later describe the functionality of the border routers in
   greater depth for each of the two realizations of the framework.

4.1.1.5 RSVP/Intserv

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     Integrated Services Operation Over Diffserv Networks   June, 1999

4.1.5 Intserv Network Regions

   Each RSVP/intserv Intserv network region consists of RSVP/intserv Intserv capable hosts and
   some number of routers.  These routers may reasonably be assumed to
   be RSVP/intserv Intserv capable, although this might not be required in the case
   of a small, over-provisioned network region. If Even if they are not RSVP/intserv
   Intserv capable, we assume that they will pass RSVP messages
   unhindered. Routers in the RSVP/intserv Intserv network region are not precluded
   from providing aggregate traffic control to non-
   quantitative some subset of the
   traffic passing through them.

4.1.1.6

4.1.6 Diffserv Network Region

   The diffserv network region supports aggregate traffic control and
   is assumed not to be capable of MF classification. Depending on the
   specific realization of the framework, some number of routers within
   the diffserv region may be RSVP aware and therefore capable of per-flow per-
   flow signaling and admission control. If devices in the diffserv
   region are not RSVP aware, they will pass RSVP messages
   transparently with negligible performance impact (see [8]). [6]).

   The diffserv network region provides two or more levels of service
   based on the DSCP in packet headers. It may include sub-regions
   managed as different administrative domains.

4.1.1.7

4.2 Service Mapping

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                      Use of RSVP with Diffserv           March, 1999

   RSVP/intserv signaling

   Intserv service requests specify an intserv service type and a set
   of quantitative parameters known as a 'flowspec'. At each hop in an
   intserv network, the RSVP/intserv Intserv service requests are interpreted in a
   form meaningful to the specific link layer medium.  For example at
   an 802.1 hop, the intserv parameters are mapped to an appropriate
   802.1p priority level [5].

   In our framework, diffserv regions of the network are analogous to
   the 802.1p capable switched segments described in [5]. Admission
   control agents Requests for diffserv network regions
   Intserv services must map intserv service
   types to a corresponding diffserv service level (DSCP be mapped onto the underlying capabilities of
   the Diffserv network region. Aspects of the mapping include:

    - selecting an appropriate PHB, or PHB) that
   can reasonably extend set of PHBs, for the intserv service type requested by the
   application. The admission control agent can then approve
      service;
    - performing appropriate policing (including, perhaps, shaping or reject
   resource requests based on
      remarking) at the capacity available in edges of the diffserv
   network Diffserv region;
    - exporting Intserv parameters from the Diffserv region at (e.g. for
      the mapped service level.

   One updating of two schemes may be used to map intserv service types to
   diffserv service levels.

4.1.1.7.1 Default Mapping

   In this scheme, there is some standard, well-known mapping from
   intserv service type to a DSCP ADSPECs);
    - performing admission control on the Intserv requests that will invoke takes
      into account the appropriate
   behavior resource availability in the diffserv network.

4.1.1.7.2 Network Driven Diffserv region.

   Exactly how these functions are performed will be a function of the
   way bandwidth is managed inside the Diffserv network region, which
   is a topic we discuss in Section 4.3.

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   When the PHB (or set of PHBs) has been selected for a particular
   Intserv flow, it may be necessary to communicate the choice of DSCP
   for the flow to other network elements. Two schemes may be used to
   achieve this end, as discussed below.

4.2.1 Default Mapping

   In this scheme, there is some standard, well-known mapping from
   intserv service type to a DSCP that will invoke the appropriate
   behavior in the diffserv network.

4.2.2 Network Driven Mapping

   In this scheme, RSVP aware conversant routers in the diffserv network
   region (perhaps at its edge) may override the well-known mapping
   described in 4.2.1. In the case that DSCPs are marked at the ingress
   to the Diffserv region, the DSCPs can simple be remarked at the
   boundary routers. However, in the case that DSCP marking occurs
   upstream of the Diffserv region, either in a host or a router, then
   the appropriate mapping needs to be communicated Upstream, to the
   marking device.  This may be accomplished using RSVP, as described
   in [14].

   The decision regarding where to mark DSCP and whether to override
   the well-known service mapping is a mater of policy to be decided by
   the administrator of the diffserv network region in cooperation with
   the administrator of the intserv network region.

4.2.3 Microflow Separation

   Boundary routers residing at the edge of the Diffserv region will
   typically police traffic submitted from the Intserv region in order
   to protect resources within the Diffserv region. This policing will
   be applied on an aggregate basis, with no regard for the individual
   microflows making up each aggregate. As a result, it is possible for
   a misbehaving microflow to claim more than its fair share of
   resources within the aggregate, thereby degrading the service
   provided to other microflows. This problem may be addressed by:

   1. Providing per microflow policing at the edge routers - this is
   generally the most appropriate location for microflow policing,
   since it pushes per-flow work to the edges of the network, where it
   scales better. In addition, since the intserv region is responsible
   for providing microflow service to its customers and the diffserv
   region is responsible for providing aggregate service to its
   customers, this distribution of functionality mirrors the
   distribution of responsibility.

   2. Providing per microflow policing at the border routers - this
   approach tends to be less scalable than the previous approach. It
   also imposes a management burden on the diffserv region of the

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   network. However, it may be appropriate in certain cases, for the
   diffserv boundary routers to offer per microflow policing as a
   value-add to its intserv customers.

   3. Relying on upstream shaping and policing - in certain cases, the
   customer may trust the shaping of certain groups of hosts
   sufficiently to not warrant reshaping or policing at the boundary
   between the intserv and diffserv regions. Note that, even if the
   hosts are shaping microflows properly, these shaped flows may become
   distorted as they transit through the intserv region of the network.
   Depending on the degree of distortion, it may override be necessary to
   somewhat over-provision the well-known mapping described aggregate capacities in 4.1.1.7.1. RSVP
   RESV messages originating from receivers will carry the usual
   intserv service type. RSVP aware routers within the diffserv network
   region may append a DCLASS [17] object
   region, or to RESV messages as they are
   forwarded upstream. When a RESV message carrying a DCLASS object
   arrives at re-police using either 1 or 2 above.
    The choice of one mechanism or another is a sending host (or in the case matter of router marking, at an
   intermediate router), policy to be
   decided by the sender starts marking transmitted packets
   with administrator of the DSCP indicated. intserv network region.

4.3 Resource Management in Diffserv Regions

   A decision variety of options exist for management of resources (e.g.,
   bandwidth) in the Diffserv network regions to override meet the well-known service mapping may be based
   on configuration and/or needs of end-
   to-end Intserv flows. These options include:

    - statically provisioned resources;
    - resources dynamically provisioned by RSVP;
    - resources dynamically provisioned by other means (e.g., a policy decision. form of
      Bandwidth Broker).

   Some of the details of using each of these different approaches are
   discussed in the following section.

5. Detailed Examples of the Interoperation Operation of RSVP/Intserv and Intserv over Diffserv Regions

   In this section we provide detailed examples of our framework in
   action. We discuss two examples, one in which the diffserv network
   region is RSVP unaware, the other in which the diffserv network
   region is RSVP aware.

5.1 RSVP Unaware Statically Provisioned Diffserv Network Region

   In this example, no devices in the diffserv network region are RSVP
   aware. The diffserv network region is statically provisioned. The
   owner(s) of the RSVP/intserv Intserv network regions and the owner of the
   diffserv network region have negotiated a static contract (service

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                      Use of RSVP with Diffserv           March, 1999
   level agreement, specification, or SLA) SLS) for the transmit capacity to be
   provided to the customer at each of a number of standard diffserv
   service levels. The _transmit capacity_ may be simply an amount of
   bandwidth or it could be a more complex _profile_ involving a number
   of factors such as burst size, peak rate, time of day etc.

   It is helpful to consider the each edge routers router in the customer network,
   to consist network
   as consisting of two halves, a standard RSVP/intserv Intserv half, which

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   interfaces to the customer's RSVP/intserv Intserv network regions and a diffserv
   half which interfaces to the diffserv network region. The
   RSVP/intserv Intserv
   half has full RSVP capability. It is able to
   participate in RSVP signaling and it is able to identify and process traffic on per-flow
   granularity.

   The diffserv half of the router can be considered to consist of a
   number of virtual transmit interfaces, one for each diffserv service
   level negotiated in the SLA. SLS. The router contains a table that
   indicates the transmit capacity provisioned, per the SLA SLS at each
   diffserv service level. This table, in conjunction with the default
   mapping described in 4.1.1.7.1, 4.2.1, is used to apply perform admission control
   decisions to on intserv flows which cross the diffserv network region.

5.1.1 Sequence of Events in Obtaining End-to-end QoS

   The following sequence illustrates the process by which an
   application obtains end-to-end QoS. QoS when RSVP is used within the
   Intserv region.

   1. The QoS process on the sending host Tx generates an RSVP PATH
   message that describes the traffic offered by the sending
   application.

   2. The PATH message is carried toward the receiving host, Rx. In the
   RSVP/intserv
   Intserv network region to which the sender is attached, standard
   RSVP/intserv processing is applied at capable network elements.

   3. At the edge router ER1, the PATH message is subjected to standard
   RSVP processing and PATH state is installed in the router. The PATH
   message is sent onward to the diffserv network region.

   4. The PATH message is carried transparently through message is ignored by routers in the diffserv network
   region and then processed at ER2 according to standard RSVP
   processing rules.

   5. When the PATH message reaches the receiving host Rx, the
   operating system generates an RSVP RESV message, indicating interest
   in offered traffic of a certain intserv service type.

   6. The RESV message is carried back towards the diffserv network
   region and the sending host. Consistent with standard RSVP/intserv
   processing, it may be rejected at any RSVP node in the RSVP/intserv Intserv
   network region if resources are deemed insufficient to carry the
   traffic requested.

   7. At ER2, the RESV message is subjected to standard RSVP/intserv
   processing.  It may be rejected if resources on the downstream

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                      Use of RSVP with Diffserv           March, 1999
   interface of ER2 are deemed insufficient to carry the resources
   requested.  If it is not rejected, it will be carried transparently
   through the diffserv network region, arriving at ER1.

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   8. In ER1, the RESV message triggers admission control processing.
   ER1 compares the resources requested in the RSVP/intserv request to
   the resources available in the diffserv network region at the
   corresponding diffserv service level. The corresponding service
   level is determined by the intserv to diffserv mapping discussed
   previously. The availability of resources is determined by the
   capacity provisioned in the SLA. SLS. ER1 may also apply a policy
   decision such that the resource request may be rejected based on the
   customer's specific policy criteria, even though the aggregate
   resources are determined to be available per the SLA. SLS.

   9. If ER1 approves the request, the RESV message is admitted and is
   allowed to continue upstream towards the sender. If it rejects the
   request, the RESV is not forwarded and the appropriate RSVP error
   messages are sent. If the request is approved, ER1 updates its
   internal tables to indicate the reduced capacity available at the
   admitted service level on its transmit interface.

   10. The RESV message proceeds through the RSVP/intserv Intserv network region to
   which the sender is attached. Any RSVP node in this region may
   reject the reservation request due to inadequate resources or
   policy. If the request is not rejected, the RESV message will arrive
   at the sending host, Tx.

   11. At Tx, the QoS process receives the RESV message. It interprets
   receipt of the message as indication that the specified traffic flow
   has been admitted for the specified intserv service type (in the
   RSVP/intserv
   Intserv network regions) and for the corresponding diffserv service
   level (in the diffserv network regions). It may also learn the
   appropriate DSCP marking to apply to packets for this flow from
   information provided in the RESV.

   12. Tx begins to may mark the DSCP in the headers of packets that are
   transmitted on the admitted traffic flow. The DSCP is may be the
   default value which maps to the intserv service type specified in
   the admitted RESV message. message, or it may be a value explicitly provided
   in the RESV..

   In this manner, we obtain end-to-end QoS through a combination of
   networks that support RSVP/Intserv and networks that support
   diffserv.

5.2 RSVP Aware RSVP-Aware Diffserv Network Region

   In this example, the customer's edge routers are standard RSVP
   routers. The border router, BR1 is RSVP aware. In addition, there
   may be other routers within the diffserv network region which are
   RSVP aware. Note that although these routers are able to participate
   in some form of RSVP signaling, they process classify and schedule traffic
   in aggregate, based on DSCP, not on the per-flow classification
   criteria used by standard RSVP/Intserv routers. It can be said that
   their control-plane is RSVP while their data-plane is diffserv. This approach exploits the

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     Integrated Services Operation Over Diffserv           March, Networks   June, 1999

   approach exploits the benefits of RSVP signaling while maintaining
   much of the scalability associated with diffserv.

   In the former preceding example, there is no RSVP signaling between the
   RSVP/intserv Intserv
   network regions and the diffserv network region. The negotiation of
   an SLA SLS is the only explicit exchange of resource availability
   information between the two network regions. ER1 is configured with
   the information represented by the SLA SLS and as such, is able to act
   as an admission control agent for the diffserv network region. Such
   configuration does not readily support dynamically changing SLAs, SLSs,
   since ER1 requires reconfiguration each time the SLA SLS changes. It is
   also difficult to make efficient use of the resources in the
   diffserv network region. This is because admission control does not
   consider the availability of resources in the diffserv network
   region along the specific path that would be impacted.

   By contrast, when the diffserv network region is RSVP aware, the
   admission control agent is part of the diffserv network. As a
   result, changes in the capacity available in the diffserv network
   region can be indicated to the RSVP/intserv Intserv network regions via
   traditional RSVP. By
   including routers interior to the diffserv network region in RSVP
   signaling, it is possible to simultaneously improve the efficiency
   of resource usage. usage within the diffserv region and to improve the
   level of confidence that the resources requested at admission
   control are indeed available at this particular point in time. This
   is because admission control can be linked to the availability of
   resources along the specific path that would be impacted. We refer
   to this benefit of RSVP signaling as 'topology aware admission
   control'. A further benefit of supporting RSVP signaling within the
   diffserv network region is that it is possible to effect changes in
   the provisioning of the diffserv network region (e.g., allocating
   more or less bandwidth to the EF queue in a router) in response to
   resource requests from the RSVP/intserv network regions.

   Various mechanisms may be used within the diffserv network region to
   support dynamic provisioning and topology aware admission control.
   These include aggregated RSVP, per-flow RSVP and bandwidth brokers,
   as described in the following paragraphs.

5.2.1 Aggregated or Tunneled RSVP

   A number of drafts [8,10,18, 19] [3,6,15, 16] propose mechanisms for extending
   RSVP to reserve resources for an aggregation of flows between edges
   of a network. Border routers may interact with core routers and
   other border routers using aggregated RSVP to reserve resources
   between edges of the diffserv network region. Initial reservation
   levels for each service level may be established between major
   border routers, based on anticipated traffic patterns. Border
   routers could trigger changes in reservation levels as a result of
   the cumulative per-flow RSVP requests from peripheral RSVP/intserv
   network regions reaching high or low-water marks.

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   In this approach, admission of per-flow RSVP requests from
   RSVP/intserv networks would be counted against the appropriate
   aggregate reservations for the corresponding service level.

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                      Use The size
   of RSVP the aggregate reservations may or may not be dynamically adjusted
   to deal with Diffserv           March, 1999 the changes in per-flow reservations.

   The advantage of this approach is that it offers dynamic, topology
   aware admission control to the diffserv network region without
   requiring the level of RSVP signaling processing that would be
   required to support per-flow RSVP.

5.2.3 Per-flow RSVP

   In this approach, described in [3], routers in the diffserv network
   region respond to the standard per-flow RSVP signaling originating
   from the
   RSVP/intserv Intserv network regions. This approach provides the
   benefits of the previous approach (dynamic, topology aware admission
   control) without requiring aggregated RSVP support. Resources are
   also used more efficiently as a result of the per-flow admission
   control. However, the demands on RSVP signaling resources within the
   diffserv network region may be significantly higher.

5.2.4 Oracle

   Border routers might not use any form of higher than in an
   aggregated RSVP signaling within the approach.

   Note that per-flow RSVP and aggregated RSVP are not mutually
   exclusive in a single diffserv network region but might instead use custom protocols to
   interact with an 'oracle'. The oracle region. It is a hypothetical agent that
   has sufficient topology awareness possible to make admission control
   decisions. The set of use per-
   flow RSVP aware routers in at the previous two
   examples can be considered collectively as a distributed oracle. In
   various definitions edges of the 'bandwidth broker' [4], it is able to act
   as a centralized oracle.

5.2.5 diffserv region and aggregation only
   in some _core_ region within the diffserv region.

5.2.4 Granularity of Deployment of RSVP Aware Routers

   In 5.2.2 and 5.2.3 some subset of the routers within the diffserv
   network is RSVP signaling aware (though traffic control is
   aggregated as opposed to per-flow). The relative number of routers
   in the core that participate in RSVP signaling is a provisioning
   decision that must be made by the network administrator.

   In one extreme case, only the border routers participate in RSVP
   signaling. In this case, either the diffserv network region must be
   extremely over-provisioned and therefore, inefficiently used, or
   else it must be carefully and statically provisioned for limited
   traffic patterns. The border routers must enforce these patterns.

   In the other extreme case, each router in the diffserv network
   region might participate in RSVP signaling. In this case, resources
   can be used with optimal efficiency, but signaling processing
   requirements and associated overhead increase. As noted above, RSVP
   aggregation is one way to limit the signaling overhead at the cost
   of some loss of optimality in resource utilization.

   It is likely that some network administrators will compromise by
   enabling RSVP signaling on some subset of routers in the diffserv
   network region. These routers will likely represent major traffic

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   switching points with over-provisioned or statically provisioned
   regions of RSVP unaware routers between them.

5.3 Dynamically Provisioned, Non-RSVP-aware Diffserv Region

   Border routers might not use any form of RSVP signaling within the
   diffserv network region but might instead use custom protocols to
   interact with an 'oracle'. The oracle is a hypothetical agent that
   has sufficient knowledge of resource availability and network
   topology to make admission control decisions. The set of RSVP aware
   routers in the previous two examples can be considered collectively
   as a form of distributed oracle. In various definitions of the
   'bandwidth broker' [4], it is able to act as a centralized oracle.

6. Implications of the Framework for DiffServ Diffserv Network Regions

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                      Use of RSVP with Diffserv           March, 1999

   We have described a framework in which RSVP/intserv style QoS can be
   provided across end-to-end paths that include diffserv network
   regions. This section discusses some of the implications of this
   framework for the diffserv network region.

6.1 Requirements from Diffserv Network Regions

   A diffserv network region must meet the following requirements in
   order for it to support the framework described in this draft.

   1. A diffserv network region must be able to provide support for the
   standard intserv QoS services between its border routers. It must be
   possible to invoke these services by use of a standard DSCP.

   2. There must be PHBs within the
   diffserv region and appropriate service mappings from intserv service
   types to these behavior at the edge of the diffserv services.

   3.
   region.

   2. Diffserv network regions must provide admission control
   information to intserv network regions.  This information can be
   provided by a dynamic protocol or, at the very least, or through static service level agreements.

   4.
   agreements enforced at the edges of the diffserv region.

   3. Diffserv network regions must be able to pass RSVP messages, in
   such a manner that they can be recovered at the egress of the
   diffserv network region. The diffserv network region may, but is not
   required to, process these messages. Mechanisms for transparently
   carrying RSVP messages across a transit network are described in
   [8,10,18, 19].
   [3,6,15, 16].

   To meet these requirements, additional work is required in the areas
   of:

   1. Mapping intserv style service specifications to services that can
   be provided by diffserv network regions.

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   2. Definition of the functionality required in network elements to
   support RSVP signaling with aggregate traffic control (for network
   elements residing in the diffserv network region).
   3. Definition of mechanisms to efficiently and dynamically provision
   resources in a diffserv network region (e.g. aggregated RSVP,
   tunneling, MPLS, etc.). This might include protocols by which an
   _oracle_ conveys information about resource availability within a
   diffserv region to border routers.

6.2 Protection of Intserv Traffic from Other Traffic

   Network administrators must be able to share resources in the
   diffserv network region between three types of traffic:

   a. RSVP/intserv signaled End-to-end Intserv traffic  - this is typically traffic
   associated with quantitative QoS applications. It requires a
   specific quantity of
   resources with a high degree resources with a high degree of assurance.

   b. Non-intserv traffic. The Diffserv region may allocate resources
   to traffic that does not make use of intserv techniques to quantify
   its requirements, e.g. through the use of static provisioning and
   SLSs enforced at the edges of assurance.

   b. Qualitative - this is the region. Such traffic might be
   associated with applications that
   are not quantitative. Its resource whose QoS requirements are not readily
   quantifiable. It requires
   quantifiable but which require a 'better than best-effort' level of
   service.

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                      Use of RSVP with Diffserv           March, 1999

   c. All other (best-effort) traffic

   These three classes of traffic must be isolated from each other by
   the appropriate configuration of policers and classifiers at ingress
   points to the diffserv network region, and by appropriate
   provisioning within the diffserv network region.  To provide
   protection for RSVP/intserv signaled Intserv traffic in diffserv regions of the network,
   we suggest that the DSCPs assigned to such traffic not overlap with
   the DSCPs assigned to other traffic.

7. Multicast

   To be written.

8. Security Considerations

8.1 General RSVP Security

   We are proposing that RSVP signaling be used to obtain resources in
   both diffserv and RSVP/intserv Intserv regions of a network. Therefore, all RSVP
   security considerations apply [11]. [9].  In addition, network
   administrators are expected to protect network resources by
   configuring secure policers at interfaces with untrusted customers.

8.2 Host Marking

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   Though it does not mandate host marking, marking of the DSCP, our proposal
   does recommend allow it. Allowing hosts to set the DSCP directly may alarm
   network administrators.  The obvious concern is that hosts may
   attempt to 'steal' resources.  In fact, hosts may attempt to exceed
   negotiated capacity in diffserv network regions at a particular
   service level regardless of whether they invoke this service level
   directly (by setting the DSCP) or indirectly (by submitting traffic
   that classifies in an intermediate marking router to a particular diff-
   serv
   diff-serv DSCP).

   In either case, it will be necessary for each diffserv network
   region to protect its resources by policing to assure that customers
   do not use more resources than they are entitled to, at each service
   level (DSCP). If the sending host does not do the marking, the
   boundary router (or trusted intermediate routers) must provide MF
   classification, mark and police. If the sending host does do the
   marking, the boundary router needs only to provide BA classification
   and to police to ensure that the customer is not exceeding the
   aggregate capacity negotiated for the service level.

   In summary, the there are no additional security concerns of raised by
   marking the DSCP at the edge of the network can be dismissed since each diffserv provider providers
   will have to police at their boundary boundaries anyway.  Furthermore, this
   approach reduces the granularity at which border routers must
   police, thereby pushing finer grain shaping and policing
   responsibility to the edges of the network, where it scales better.
   The larger diffserv network regions are thus focused on the task of
   protecting their networks,

Bernet, ed. et. al                                                  16
                      Use of RSVP with Diffserv           March, 1999 while the RSVP/intserv Intserv network regions are
   focused on the task of shaping and policing their own traffic to be
   in compliance with their negotiated intserv parameters.

   7.

9. Acknowledgments

   Authors thank the following individuals for their comments that led
   to improvements to the previous version(s) of this draft: David
   Oran, Andy Veitch, Curtis Villamizer, Walter Weiss, Francois le
   Faucheur and Russel Russell White.

   Many of the ideas in this document have been previously discussed in
   the original intserv architecture document [12].

   8. [10].

10. References

   [1] Braden, R., Zhang, L., Berson, S., Herzog, S. and Jamin, S.,
       "Resource Reservation Protocol (RSVP) Version 1 Functional
       Specification", RFC 2205, Proposed Standard, September 1997

   [2] Yavatkar, R., Hoffman, D., Bernet, Y., Baker, F. and Speer, M.,
       "SBM (Subnet Bandwidth Manager): A Protocol For RSVP-based
       Admission Control Over IEEE 802 Style Networks", Internet Draft,

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     Integrated Services Operation Over Diffserv Networks   June, 1999

   [3] Berson, S. and Vincent, R., "Aggregation of Internet Integrated
      Services State", Internet Draft, December 1997. draft-berson-rsvp-aggregation-
      00.txt, August 1998.

   [4] Nichols, K., Jacobson, V. and Zhang, L., "A Two-bit
       Differentiated Services Architecture for the Internet", Internet
       Draft, December 1997. draft-nichols-diff-svc-arch-01.txt, April 1999.

   [5] Seaman, M., Smith, A. and A., Crawley, E., "Integrated Services Over
   [6] Elleson, E. and Blake, S., "A Proposal for the Format and
       Semantics of the TOS Byte and Traffic Class Byte in Ipv4 and
       Ipv6 Headers", Internet Draft, November 1997

   [7] Ferguson, P., "Simple Differential Services: IP TOS and
       Precedence, Delay Indication, and Drop Preference", Wroclawski, J.,
       "Integrated Service Mappings on IEEE 802 Networks", Internet
   [8]
   [6] Guerin, R., Blake, S. and Herzog, S.,"Aggregating RSVP based QoS
       Requests", Internet Draft, draft-guerin-aggreg-rsvp-00.txt,
       November 1997.

   [9]

   [7] Nichols, Kathleen, et al., "Definition of the Differentiated
       Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC
       2474, December 1998.

   [10]

   [8] Blake, S., et al., "An Architecture for Differentiated
        Services." RFC 2475, December 1998.

   [11]

   [9] Baker, F., "RSVP Cryptographic Authentication", Internet Draft,

Bernet, ed. et. al                                                  17
                      Use of RSVP with Diffserv           March,
        draft-ietf-rsvp-md5-08.txt, February 1999

        August 1997

   [12]

   [10] Braden, R., Clark, D. and Shenker, S., "Integrated Services in
        the Internet Architecture: an Overview", Internet RFC 1633,
   [13]
   [11] Garrett, M. W., and Borden, M., "Interoperation of Controlled-
        Load Service and Guaranteed Service with ATM", RFC2381, August
        1998.

   [14]

   [12] Weiss, Walter, Private communication, November 1998.

   [15] Berson, S. and Vincent, S., "Aggregation of Internet Integrated
        Services State", Internet Draft, August 1998.

   [16]

   [13] Kent, S., Atkinson, R., "Security Architecture for the Internet
        Protocol", RFC 2401, November 1998.

   [17]

   [14] Bernet, Y., "Usage and Format of the DCLASS Object with RSVP
        Signaling", Internet Draft, draft-bernet-dclass-00.txt,
        February 1999.

   [18]

   [15] Baker, F., Iturralde, C., le Faucheur, F., and Davie, B. "RSVP
        Reservation Aggregation", Internet Draft, draft-baker-rsvp-
        aggregation-00.txt, February 1999.

   [19]

   [16] Terzis, A., Krawczyk, J., Wroclawski, J., Zhang, L., "RSVP
        Operation Over IP Tunnels", Internet Draft, February draft-ietf-rsvp-
        tunnel-03.txt, April 1999.

Bernet, ed. et al.                                                  21

     Integrated Services Operation Over Diffserv Networks   June, 1999

   [17] Boyle, J., Cohen, R., Durham, D., Herzog, S., Rajan, D., and
        Sastry, A., _COPS Usage for RSVP_, Internet Draft, draft-ietf-
        rap-cops-rsvp-05.txt, June 1999.

Author's Addresses:

   Yoram Bernet
   Microsoft
   One Microsoft Way, Redmond, WA 98052
   Phone: (425) 936-9568
   Email: yoramb@microsoft.com

   Raj Yavatkar
   Intel Corporation
   JF3-206 2111 NE 25th. Avenue, Hillsboro, OR 97124
   Phone: (503) 264-9077
   Email: raj.yavatkar@intel.com

   Peter Ford
   Microsoft
   One Microsoft Way, Redmond, WA 98052
   Phone: (425) 703-2032
   Email: peterf@microsoft.com

   Fred Baker
   Cisco Systems
   519 Lado Drive, Santa Barbara, CA 93111
   Phone: (408) 526-4257
   Email: fred@cisco.com

   Lixia Zhang

Bernet, ed. et. al                                                  18
                      Use of RSVP with Diffserv           March, 1999
   UCLA
   4531G Boelter Hall Los Angeles, CA 90095
   Phone: +1 310-825-2695
   Email: lixia@cs.ucla.edu

   Michael Speer
   Sun Microsystems
   901 San Antonio Road UMPK15-215 Palo Alto, CA 94303
   Phone: +1 650-786-6368
   Email: speer@Eng.Sun.COM

   Bob Braden
   USC Information Sciences Institute
   4676 Admiralty Way Marina del Rey, CA 90292-6695
   Phone: 310-822-1511
   Email: braden@isi.edu

   Bruce Davie
   Cisco Systems
   250 Apollo Drive, Chelmsford, MA 01824
   Phone: (978)-244-8000

Bernet, ed. et al.                                                  22

     Integrated Services Operation Over Diffserv Networks   June, 1999

   Email: bsd@cisco.com

   This draft expires September, December, 1999

Bernet, ed. et. al                                                  19 et al.                                                  23