Network Working Group                                       C. Jacquenet 
Internet Draft                                        France Telecom R&D 
Document: draft-jacquenet-ip-te-cops-02.txt                    June 2001 
Category: Experimental                                                   
Expires December 2001                                                    
 
 
             A COPS client-type for IP traffic engineering 
                  <draft-jacquenet-ip-te-cops-02.txt> 
 
 
Status of this Memo 
 
   This document is an Internet-Draft and is in full conformance with 
   all provisions of Section 10 of RFC 2026 [1].  
    
   Internet-Drafts are working documents of the Internet Engineering 
   Task Force (IETF), its areas, and its working groups. Note that other 
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   Internet-Drafts are draft documents valid for a maximum of six months 
   and may be updated, replaced, or obsoleted by other documents at any 
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   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 
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Abstract 
    
   This draft specifies a COPS (Common Open Policy Service, [2]) client-
   type designed for the enforcement of IP Traffic Engineering (IP TE) 
   policies within IP networks. The usage of this IP TE COPS client-type 
   is based upon the activation of the COPS protocol for policy 
   provisioning purposes (COPS-PR, [3]). 
    
1. Introduction 
    
   The deployment of value-added IP services (like quality-of-service-
   based IP Virtual Private Networks) over the Internet has become one 
   of the most competing challenges for service providers, as well as a 
   complex technical issue, as far as the appropriate provisioning and 
   usage of the resources of the IP networks is concerned. 
    
   From this standpoint, the COPS protocol and its usage for the support 
   of Policy Provisioning is one of the ongoing specification effort of 
   the Resource Allocation Protocol (rap) Working Group of the IETF that 
   should help service providers in dynamically enforcing an IP Traffic 

 
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   Engineering (IP TE) policy which is one of the key components for the 
   massive development of the above-mentioned IP services. 
    
   Indeed, an IP traffic engineering policy aims at appropriately 
   provisioning, allocating/de-allocating, and using the switching and 
   the transmission resources of an IP network (i.e. the routers and the 
   links that connect these routers, respectively), according to the 
   Quality of Service (QoS) requirements (e.g. rate, one-way delay, 
   inter-packet delay variation, etc.) expressed by the customers who 
   can access such resources within the context of a given service 
   subscription procedure ([4]), among other considerations (like 
   network dimensioning and planning, for example). 
    
   Within the context of this document, the actual enforcement of an IP 
   traffic engineering policy is primarily based upon the activation of 
   both intra- and inter-domain dynamic routing protocols ([5], [6]) 
   that will be activated in the network to appropriately select, 
   install, maintain and possibly withdraw routes that will comply with 
   the above-mentioned QoS requirements and/or specific routing 
   constraints, depending on the type of traffic that will be conveyed 
   along these routes. 
    
   It is therefore necessary to provide the route selection processes 
   with the information that will exactly reflect these QoS 
   requirements, given the dynamic routing protocols support traffic 
   engineering capabilities for the calculation and the selection of 
   such routes. These capabilities are currently being specified in [7] 
   and [8] for the OSPF (Open Shortest Path First, [5]) and the IS-IS 
   (Intermediate System to Intermediate System routing protocol, [9]) 
   interior routing protocols respectively, while there is an equivalent 
   and ongoing specification effort for the BGP4 (Border Gateway 
   Protocol, version 4) protocol, as described in [10], for example. 
    
   To provide the route selection processes with the above-mentioned 
   configuration information, one possibility is to use the COPS 
   protocol and its usage for policy provisioning. To do so, a new COPS 
   client-type is specified, the "IP Traffic Engineering" (IP TE) 
   client-type, and this specification effort is the purpose of this 
   draft. 
    
   This document is organized into the following sections: 
    
   - Section 4 introduces terminology as well as basic assumptions, 
   - Section 5 introduces the generic architecture, 
   - Section 6 defines the contents of the COPS messages that MUST 
     include the IP TE client-type specific information, 
   - Section 7 defines the usage of the IP TE client-type, including 
     its mode of operation with the PDP (Policy Decision Point, [11]) 
     with whom a COPS communication has been established, 
   - Finally, sections 8 and 9 introduce IANA and some security 
     considerations, respectively. 
     
 
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2. Changes since the last version 
    
   The current version of this draft reflects the following changes: 
    
   - Updated bibliography, 
    
   - Slight re-wording of sections 1, 5 and 6, 
    
   - Correction of remaining typos. 
    
3. Conventions used in this document 
    
   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this 
   document are to be interpreted as described in RFC 2119 [12]. 
    
4. Terminology considerations 
    
   The enforcement of an IP traffic engineering policy is based upon the 
   processing of the information that reflects the QoS requirements 
   expressed by a customer during a service subscription procedure. Such 
   a procedure can be gracefully based upon a Service Level 
   Specification (SLS) template that will be negotiated between the 
   customer and the provider, as described in [4]. From this standpoint, 
   such QoS requirements can be expressed in terms of rate, one-way 
   delay, inter-packet delay variation, DSCP (Diff-Serv Code Point, 
   [13]) marking, or a combination of these various parameters.  
    
   This information is called the "QoS-related" information within the 
   context of this draft. 
    
   Then, this QoS-related information must be taken into account by the 
   routing processes that will participate in the calculation, the 
   selection, the installation and the maintenance of the routes that 
   will comply with the above-mentioned QoS requirements. From this 
   perspective, the algorithms invoked by the routing processes take 
   into account the cost metrics (whose corresponding values can 
   possibly be influenced by a DSCP value) that have been assigned by 
   the network administrators, and that will somewhat reflect the QoS 
   parameters that have been valued in the above-mentioned SLS template 
   ([7], [10]).  
    
   This metric-related information is called the "IP TE"-related 
   information within the context of this draft. 
    
   Thus, this draft makes a distinction between QoS-related information 
   and IP TE-related information, where: 
    
   - QoS-related information is negotiated between customers and 
     service providers (e.g. by using SLS templates), 
    

 
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   - IP TE-related information is provided to routers (as a 
     configuration input), and is exchanged between routers so that 
     they calculate, select, install, maintain and possibly withdraw 
     the routes that will comply with the parameters that are depicted 
     by the QoS-related information. 
    
   From this perspective, QoS-related information provides information 
   on the traffic to be forwarded in the network (such as source 
   address, destination address, protocol identification, DSCP marking, 
   etc.), whereas IP TE-related information provides information for the 
   routing processes that will indicate the routers of the network how 
   to forward the above-mentioned traffic, i.e. identify and use the IP 
   TE routes that will convey such traffic. 
     
   Furthermore, the actual enforcement of a given IP traffic engineering 
   policy implies that the routers must be provided with the IP TE-
   related information to compute the corresponding IP TE routes. 
                                                                
   Given these basic assumptions, this draft aims at specifying a COPS-
   based IP-TE client-type that has the following characteristics: 
    
   - The IP-TE client-type is supported by the PEP (Policy Enforcement 
     Point, [11]) capability that allows a router to enforce a 
     collection of policies (including an IP traffic engineering policy 
     within the context of this draft), thanks to a COPS communication 
     that has been established between the PEP and the PDP, 
    
   - The actual enforcement of an IP TE policy is based upon the IP TE-
     related configuration information that will be exchanged between 
     the PEP and the PDP, and that will be used by the router for 
     selecting, installing, maintaining and possibly withdrawing IP TE 
     routes. 
    
5. The generic model of an IP TE policy enforcement scheme 
                                
   The use of the COPS protocol for dynamically enforcing an IP TE 
   policy yields the generic model depicted in figure 1. 
    
             +----------------+ 
             |                | 
             |    IP Router   |            
             |                |                   
             |     +-----+    |   COPS-PR     +-----+    +-----------+ 
             |     | PEP |<---|-------------->| PDP |<-->| IP TE PIB |   
             |     +-----+    |               +-----+    +-----------+ 
             |        |       | 
             |        |       | 
             |     +-----+    | 
             |     | LPDP|    | 
             |     +-----+    | 
             |        |       | 
             |        |       | 
 
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             |    /-------\   | 
             |    |       |   | 
             | +-----+ +-----+| 
             | | RIB |.| RIB || 
             | +-----+ +-----+| 
             |    |       |   | 
             |    |       |   | 
             |    \-------/   | 
             |        |       | 
             |     +-----+    | 
             |     | FIB |    | 
             |     +-----+    |    
             +----------------+ 
     
         - Fig.1: generic model of an IP TE policy enforcement scheme - 
    
   According to figure 1, the routers embed the following and basic 
   components (among other capabilities which are clearly out of the 
   scope of this draft): 
     
   - A PEP capability, which supports the IP TE client-type. The IP TE 
     client-type is specified by the PEP to the PDP, and is unique for 
     the area covered by the IP traffic engineering policy, so that the 
     PEP can treat all the COPS client-types it supports as non-
     overlapping and independent namespaces, 
    
   - A Local Policy Decision Point (LPDP, [11]), which can be 
     assimilated to the routing processes that have been activated in 
     the router, typically. Within the context of enforcing an IP 
     traffic engineering policy, the LPDP is expected to calculate and 
     install the IP TE routes that comply with the QoS requirements 
     expressed in the IP TE-related information that has been received 
     by the PEP (see section 6 of this draft), 
    
   - Several instances of Routing Information Bases (RIB), according to 
     the different routing processes that have been activated - one can 
     easily assume the activation of at least one IGP (Interior Gateway 
     Protocol, like OSPF) and BGP4. From this standpoint, the above 
     figure does not make any specific assumption about the actual 
     number of RIB instances that can be supported by the router, since 
     this is an implementation specific issue, 
    
   - Conceptually one Forwarding Information Base (FIB), which will 
     store the routes that have been selected by the routing processes. 
     Again, this draft makes no assumption about the number of FIBs 
     that can be supported by a router (e.g. within the context of an 
     IP VPN (Virtual Private Network) service offering).  
    
   As suggested in [14], the enforcement of an IP traffic engineering 
   policy is based upon the use of an IP TE policy server (the PDP in 
   the above figure) that sends IP TE-related information to the PEP 
   capability embedded in the IP router.  
 
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   The IP TE-related information is stored and maintained in the IP TE 
   Policy Information Base ([15]), which will be accessed by the PDP to 
   retrieve and update the IP TE-related information whenever necessary 
   (see section 6 of this draft). 
    
   The IP TE-related information is conveyed between the PDP and the PEP 
   thanks to the establishment of a COPS-PR connection between these two 
   entities. The COPS-PR protocol assumes a named data structure (the 
   PIB), so as to identify the type and purpose of the policy 
   information that is sent by the PDP to the PEP for the provisioning 
   of a given policy. 
    
   Within the context of this draft, the data structure of the PIB 
   refers to the IP traffic engineering policy that is therefore 
   described in the PIB as a collection of PRovisioning Classes (PRC, 
   [3]), namely the classes described in [15]. Furthermore, these 
   classes contain attributes that actually describe the IP TE-related 
   information that will be sent by the PDP to the PEP. These attributes 
   consist of the link and traffic engineering metrics that will be 
   manipulated by the routing processes being activated in the routers 
   to calculate the IP TE routes for a given destination, among other 
   characteristics. 
    
   The IP TE classes are instantiated as multiple PRI (PRovisioning 
   Instance) instances, each of which being identified by PRovisioning 
   Instance iDentifier (PRID). A given PRI specifies the data content 
   carried in the IP TE client specific objects. An IP TE PRI typically 
   contains a value for each attribute that has been defined for the IP 
   TE PRC. 
    
   Currently, the IP TE PIB as depicted in [15] has identified a per-
   DSCP IP TE PRC instantiation scheme, because the DSCP value conveyed 
   in each IP datagram that will be processed by the routers naturally 
   yields the notion of "DSCP-based" routing. Such a routing scheme aims 
   at reflecting the IP traffic engineering policies that have been 
   defined by a service provider, assuming a restricted number of DSCP-
   identified classes of service that will service the customers' 
   requirements.  
    
   This approach clearly assumes that each service provider will have 
   the ability to instantiate the contents of its own IP TE PIB, 
   according to the routing policies that have been defined for 
   forwarding the traffic within its domain, but also outside of its 
   domain, in terms of IGP metrics' values and BGP4 attribute values, 
   respectively. 
    
6. IP TE client-type specific information to be carried in COPS messages 
    
   This section describes the formalism that is specific to the use of 
   an IP TE client-type, given that only the COPS messages that require 
   an IP TE client-type specific definition are described in this 
 
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   section, i.e. the other COPS messages to be exchanged between a PEP 
   that supports the IP TE client-type and a PDP, and which do not need 
   to carry IP TE client-type specific information are those described 
   in the corresponding [2] and [3] documents, without any further 
   elaboration. 
    
   It must be noted that, whatever the contents of the COPS messages 
   that MAY be exchanged between the PEP supporting the IP TE client-
   type and the PDP, the actual calculation, selection, installation, 
   maintenance and possible withdrawal of IP TE routes in the router's 
   FIB is left to the routers, but the route selection process is 
   influenced by the configuration information sent by the PDP, and 
   which will be processed by the IP TE client-type supported by the 
   PEP, so that the LPDP of the router can convert the IP TE-related 
   information into local configuration information.  
    
   Nevertheless, the information contained in the router's FIB MUST be 
   consistent with the information contained in the IP TE PIB: this is 
   done thanks to the synchronization features of the COPS machinery, as 
   defined in [2]. 
    
6.1. Client-type field of the Common Header of every COPS message 
    
   All of the IP TE client-type COPS messages MUST contain the COPS 
   Common Header with the 2-byte encoded Client-Type field valued with 
   the yet-to-be assigned IANA number (see section 8 of this draft) for 
   the IP TE client-type. 
    
6.2. COPS Message Content 
    
6.2.1. Request messages (REQ) 
    
   The REQ message is sent by the IP TE client-type to issue a 
   configuration request to the PDP, as specified in the COPS Context 
   Object. The REQ message includes the current configuration 
   information related to the enforcement of an IP traffic engineering 
   policy. Such configuration information is encoded according to the 
   ClientSI format that is defined for the Named ClientSI object of the 
   REQ message ([3]).  
    
   The configuration information is encoded as a collection of bindings 
   that associate a PRID object and an Encoded Provisioning Instance 
   Data (EPD, [3]).  
    
   Such information MAY consist of: 
    
   - The identification information of the router, e.g. the 
     identification information that is conveyed in OSPF LSA (Link 
     State Advertisement, [5]) Type 1 messages, which include the 
     RouterID information encoded as an IP address. The use of a 
     loopback interface's IP address is highly recommended for the 
     instantiation of the corresponding EPD, 
 
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   - The link metric values that have been currently assigned to each 
     (physical/logical) interface of the router, as described in [5] 
     for example. Such values MAY vary with an associated DSCP value, 
     i.e. the link metric assigned to an interface is a function of the 
     DSCP value encoded in each IP datagram that this router may have 
     to forward. For example, a service provider may decide to assign 
     higher values of the link metric for the selection of the routes 
     that will convey best effort traffic characterized by the default 
     DSCP value of 0x000000, 
    
   - The traffic engineering metric values that specify the link metric 
     values for traffic engineering purposes, as defined in [7], for 
     example. These values MAY be different from the above-mentioned 
     link metric values and they MAY also vary according to DSCP 
     values: e.g., this would indicate that the link is a member of one 
     or several DSCP-defined groups. 
    
6.2.2. Decision messages (DEC) 
    
   The DEC messages are used by the PDP to send IP TE policy 
   provisioning information to the IP TE client-type. DEC messages are 
   sent in response to a REQ message received from the PEP, or they can 
   be unsolicited, e.g. subsequent DEC messages can be sent at any time 
   after to supply the PEP with additional or updated IP TE policy 
   configuration information without the solicited message flag set in 
   the COPS message header, since such messages correspond to 
   unsolicited decisions. 
    
   DEC messages typically consist of "install" and/or "remove" 
   decisions, and, when there is no Decision Flags set, the DEC message 
   includes the Named Decision Data (Provisioning) object. 
    
   Apart from the above-mentioned identification information, and 
   according to the kind of (PRID, EPD) bindings that MAY be processed 
   by the PEP (see section 6.2.1. of the draft), DEC messages MAY refer 
   to the following decision examples: 
    
   - Install (i.e. assign in this case) new link/traffic engineering 
     metric values each time a new interface is installed/created on 
     the router. These new values will obviously yield the generation 
     of LSA messages in the case of the activation of the OSPF 
     protocol, and/or the generation of BGP4 UPDATE messages (e.g. in 
     the case of a new instantiation of the MULTI_EXIT_DISC (MED, [6]) 
     attribute). This will in turn yield the calculation of (new) IP TE 
     routes that MAY be installed in the router's FIB, 
    
   - Modify already-assigned metric values, thanks to a remove/install 
     decision procedure (this may yield a modification of the router's 
     FIB as well, obviously). These DEC messages can be sent because of 
     the processing of recently accepted SLS templates, 
    
 
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   - Remove assigned metric values, i.e. the corresponding interfaces 
     may not be taken into consideration by the routing algorithms 
     anymore (or during a specific period of time, e.g. for maintenance 
     purposes). 
    
6.2.3. Report messages (RPT) 
    
   The Report message allow the PEP to indicate to the PDP that a 
   particular set of IP TE policy provisioning instances have been 
   successfully or unsuccessfully installed/removed. 
    
   When the PEP receives a DEC message from the PDP, it MUST send back a 
   RPT message towards the PDP. The RPT message will contain one of the 
   following Report-Type: 
    
   "Failure":    notification of errors that occurred during the 
                 processing of the (PRID, EPD) bindings contained in 
                 the DEC message. Such a notification procedure can 
                 include a failure report in assigning an updated value 
                 of a given metric for example,  
    
   "Success":    notification of successful assignment of metric 
                 values, and/or successful installation of IP TE routes 
                 in the router's FIB. From this perspective, there MAY 
                 be routes that will be installed in the router's FIB 
                 without any explicit decision sent by the PDP to the 
                 PEP w.r.t. the calculation/installation of the above-
                 mentioned route. This typically reflects a normal 
                 dynamic routing procedure, whenever route 
                 advertisement messages are received by the router, 
                 including messages related to a topology change. In 
                 any case (i.e. whatever the effect that yielded the 
                 installation of a route in the router's FIB), a RPT 
                 message MUST be sent by the PEP towards the PDP to 
                 notify such an event, so that the IP TE PIB might be 
                 appropriately updated by the PDP.  
    
   "Accounting": the accounting RPT message will carry statistical 
                 information related to the traffic that will transit 
                 through the router. This statistical information MAY 
                 be used by the PDP to possibly modify the metric 
                 values that have been assigned when thresholds have 
                 been crossed: for example, if the RPT message reports 
                 that x % of the available rate associated to a given 
                 interface have been reached, then the PDP may send an 
                 unsolicited DEC message in return, so that potential 
                 bottlenecks be avoided.  
    
6.3. Backward compatibility issues 
    
   In the case where the IP network is composed of COPS-aware routers 
   (which embed a PEP capability that supports the IP TE client-type), 
 
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   and of COPS-unaware routers, the activation of a link state routing 
   protocol (like OSPF) together with the reporting mechanism that has 
   been described in section 6.2.of this draft addresses the backward 
   compatibility issue. 
    
   Indeed, the flooding mechanism that is used by the OSPF protocol for 
   the propagation of the LSA messages assumes that, in particular, the 
   COPS-aware routers will receive these update messages. Upon receipt 
   of such messages, the PEP will have the ability to notify the PDP of 
   the corresponding changes (e.g. by using a "Success" report-type that 
   will reflect the installation of new routes in the router's FIB), so 
   that the IP TE PIB can be updated accordingly. 
    
   The same observation can be made within the context of the activation 
   of the BGP4 protocol, because of the iBGP full-mesh topology that is 
   required to allow the routers of a given domain to get a homogeneous 
   view of the "outside" world. 
    
7. COPS-PR Usage of the IP TE client-type 
    
   After having opened a COPS connection with the PDP, the PEP sends a 
   REQ message to the PDP that will contain a Client Handle. The Client 
   Handle is used to identify a specific request state associated to the 
   IP TE client-type supported by the PEP. The REQ message will contain 
   a "Configuration Request" context object. 
    
   This REQ message will also carry the named client specific 
   information (including the (default) configuration information), as 
   described in section 6.2.1.of the draft. By "default" configuration 
   information, it must be understood the default values that can be 
   assigned to the different metrics considered in this document, 
   according to the bootstrap procedures of the routers, and to the 
   default values that have been instantiated in the IP TE PRC part of 
   the PIB. 
    
   The routes that have been installed in the router's FIB may be 
   conveyed in specific (PRID, EPD) bindings in the REQ message as well.  
    
   Upon receipt of the REQ message, the PDP will send back a DEC message 
   towards the PEP. This DEC message will carry IP TE Named Decision 
   Data object that will convey all the appropriate installation/removal 
   of (PRID, EPD), as described in section 6.2.2 of this draft. One of 
   the basic goals of this named Decision objects consist in making the 
   routers calculate and install the IP TE routes that will comply with 
   the requirements contained in the SLS templates that have been 
   accepted by the service provider, as well as enforce the IP traffic 
   engineering policy that is depicted by the above-mentioned metric 
   value assignment. 
    
   Upon receipt of a DEC message, the PEP and the IP TE client-type it 
   supports will (try to) enforce the corresponding IP TE decisions, by 
   making the LPDP (and its associated implementation-specific Command 
 
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   Line Interface, if necessary) install the named IP TE policy data 
   (e.g. assign a metric value to a recently-installed interface). 
    
   Then, the PEP will notify the PDP about the actual enforcement of the 
   named IP TE policy decision data, by sending the appropriate RPT 
   message back to the PDP. Depending on the report-type that will be 
   carried in the RPT message, the contents of the message MAY include: 
    
   - Successfully/unsuccessfully assigned new/updated metric values, 
    
   - Successfully installed routes from the router's FIB. Note that the 
     notion of "unsuccessfully installed routes" is meaningless, 
    
   - Successfully/unsuccessfully withdrawn routes from the router's 
     FIB. Route withdrawal is not only subject to the normal IGP and 
     BGP4 procedures (thus yielding the generation of the corresponding 
     advertisement messages), but also subject to named IP TE policy 
     decision data (carried in a specific DEC message), like those data 
     related to the lifetime of a service: from this standpoint, an 
     installed route may be valid ONLY during the operating hours of a 
     company, for example. 
    
   The RPT message MAY also carry the "Accounting" report-type, as 
   described in section 6.2.3.of this draft.  
    
8. IANA Considerations  
    
   Section 6.1.of this draft has identified a need for the assignment of 
   a specific number that will uniquely identify the IP TE client-type 
   in every COPS message to be exchanged between a PEP and a PDP.  
    
   This value SHOULD be chosen in the range of 0x8000 - 0xFFFF,according 
   to a First Come First Served policy, as mentioned in both [2] and 
   [16]. 
                                          
9. Security Considerations 
    
   This draft specifies a new client-type that will make use of the COPS 
   protocol for the provisioning and the enforcement of IP traffic 
   engineering policies. As such, it introduces no new security issues 
   over the COPS protocol itself, or its usage for policy provisioning.  
    
   Nevertheless, it is recommended that the IP-TE client-type 
   systematically uses the Message Integrity Object (Integrity) for the 
   authentication and the validation of every COPS message it may 
   exchange with the PDP with whom it has established a COPS 
   communication. The Message Integrity Object also prevents from replay 
   attacks. 
    
   In addition, the IP Security ([17]) protocol suite may be activated, 
   and the IPSec Authentication Header (AH) should be used for the 
   validation of the COPS connection, while the Encapsulated Security 
 
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   Payload (ESP) may be used to provide both validation and secrecy, as 
   stated in [2]. 
         
10. References 
 
   [1]  Bradner, S.,"The Internet Standards Process -- Revision 3", BCP 
        9, RFC 2026, October 1996. 
   [2]  Boyle, J., Cohen, R., Durham, D., Herzog, S., Raja R., Sastry 
        A., "The COPS (Common Open Policy Service) Protocol", RFC 2748, 
        Proposed Standard, January 2000. 
   [3]  Ho Chan, K., Durham, D., Gai, S., Herzog, S., McLoghrie, K., 
        Reichmeyer, F., Seligson, J., Smith, A., Yavatkar, R., "COPS 
        Usage for Policy Provisioning (COPS-PR)", RFC 3084, March 2001. 
   [4]  Goderis, D., T'Joens, Y., Jacquenet, C., Memenios, G., Pavlou, 
        G., Egan, R., Griffin, D., Georgatsos, P., Georgiadis, L., 
        "Specification of a Service Level Specification (SLS) 
        Template", draft-tequila-sls-00.txt, Work in Progress, November 
        2000. Check http://www.ist-tequila.org for additional 
        information. 
   [5]  Moy, J.,"OSPF Version 2", RFC 2328, April 1998. 
   [6]  Rekhter, Y., Li T., "A Border Gateway Protocol 4 (BGP-4)", RFC 
        1771, March 1995. 
   [7]  Katz, D., Yeung, D., Kompella, K., "Traffic Engineering 
        Extensions to OSPF", draft-katz-yeung-ospf-traffic-04.txt, Work 
        in Progress, February 2001. 
   [8]  Smit, H., Li T., "IS-IS Extensions for Traffic Engineering", 
        draft-ietf-isis-traffic-02.txt, Work in Progress, September 
        2000. 
   [9]  ISO/IEC 10589, "Intermediate System to Intermediate System, 
        Intra-Domain Routing Exchange Protocol for use in Conjunction 
        with the Protocol for Providing the Connectionless-mode Network 
        Service (ISO 8473)", June 1992. 
   [10] Jacquenet, C., "Providing Quality of Service Indication by the 
        BGP-4 Protocol: the QOS_NLRI Attribute", draft-jacquenet-qos-
        nrli-01.txt, Work in Progress, February 2001. 
   [11] Yavatkar, R., Pendarakis, D., Guerin, R., "A Framework for 
        Policy-Based Admission Control", RFC 2753, January 2000. 
   [12] Bradner, S., "Key words for use in RFCs to Indicate Requirement 
        Levels", BCP 14, RFC 2119, March 1997. 
   [13] Nichols K., Blake S., Baker F., Black D., "Definition of the 
        Differentiated Services Field (DS Field) in the IPv4 and IPv6 
        Headers", RFC 2474, December 1998. 
   [14] Apostopoulos G., Guerin R., Kamat S., Tripathi S. K., "Server 
        Based QOS Routing", Proceedings of the 1999 GLOBCOMM 
        Conference. 
   [15] Jacquenet C., "An IP Traffic Engineering Policy Information 
        Base", draft-jacquenet-ip-te-pib-00.txt, Work in Progress, June 
        2001. 
   [16] Alvestrand H., Narten T., "Guidelines for Writing an IANA 
        Considerations Section in RFCs", BCP 26, RFC 2434, October 
        1998. 
 
 
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   [17] Atkinson R., "Security Architecture for the Internet Protocol", 
        RFC 2401, August 1998. 
    
11. Acknowledgments 
                         
   Part of this work is funded by the European Commission, within the 
   context of the TEQUILA (Traffic Engineering for Quality of Service in 
   the Internet At Large Scale, [4]) project, which is itself part of 
   the IST (Information Society Technologies) research program. 
    
   The author would also like to thank all the partners of the TEQUILA 
   project for the fruitful discussions that have been conducted so far 
   within the context of the traffic engineering specification effort of 
   the project, as well as M. Brunner for his valuable input. 
    
    
12. Author's Addresses 
    
   Christian Jacquenet 
   France Telecom R & D 
   DMI/SIR 
   42, rue des Coutures 
   BP 6243 
   14066 CAEN Cedex 04 
   France 
   Phone: +33 2 31 75 94 28 
   Email: christian.jacquenet@francetelecom.com 
    
13. 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 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 
 
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   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 
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