One document matched: draft-lefaucheur-rsvp-dste-00.txt


                                                             
   Internet Draft                                  Francois Le Faucheur 
                                                       Michael Dibiasio 
                                                            Bruce Davie 
                                                    Cisco Systems, Inc. 
                                                                        
                                                      Michael Davenport 
                                                         Chris Christou 
                                                    Booz Allen Hamilton 
   draft-lefaucheur-rsvp-dste-00.txt                                    
   Expires: January 2005                                      July 2004 
    
    
        Aggregation of RSVP Reservations over MPLS TE/DS-TE Tunnels 
    
    
Intellectual Property Rights (IPR) Statement 
    
   By submitting this Internet-Draft, I certify that any applicable 
   patent or other IPR claims of which I am aware have been disclosed, 
   or will be disclosed, and any of which I become aware will be 
   disclosed, in accordance with RFC 3668. 
    
    
Status of this Memo 
    
   Internet-Drafts are working documents of the Internet Engineering 
   Task Force (IETF), its areas, and its working groups.  Note that 
   other groups may also distribute working documents as Internet-
   Drafts. 
    
   Internet-Drafts are draft documents valid for a maximum of six months 
   and may be updated, replaced, or obsoleted by other documents at any 
   time.  It is inappropriate to use Internet-Drafts as reference 
   material or to cite them other than a "work in progress." 
    
   The list of current Internet-Drafts can be accessed at 
   http://www.ietf.org/1id-abstracts.html 
    
   The list of Internet-Draft Shadow Directories can be accessed at 
   http://www.ietf.org/shadow.html 
    
    
Abstract 
    
   This document provides specification for aggregation of RSVP end-to-
   end reservations over MPLS Traffic Engineering (TE) tunnels or MPLS 
   Diffserv-aware MPLS Traffic Engineering (DS-TE) Tunnels. This 
   approach is based on RFC 3175 and simply modifies the corresponding 
 
 
Le Faucheur, et al.                                           [Page 1] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   procedures for operations over MPLS TE tunnels instead of aggregated 
   RSVP reservations. This approach can be used to achieve admission 
   control of a very large number of flows in a scalable manner since 
   the devices in the core of the network are unaware of the end-to-end 
   RSVP reservations and are only aware of the MPLS TE tunnels. 
    
 
Specification of Requirements 
    
   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 [RFC2119]. 
    
    
1.   
    Introduction 
    
   The Integrated Services (Intserv) [INT-SERV] architecture provides a 
   means for the delivery of end-to-end Quality of Service (QoS) to 
   applications over heterogeneous networks.  
    
   [RSVP] defines the Resource reSerVation Protocol which can be used by 
   applications to request resources from the network. The network 
   responds by explicitely admitting or rejecting these RSVP requests. 
   Certain applications that have quantifiable resource requirements 
   express these requirements using Intserv parameters as defined in the 
   appropriate Intserv service specifications ([GUARANTEED], 
   [CONTROLLED]). 
    
   The Differentiated Services (DiffServ) architecture ([DIFFSERV]) was 
   then developed to support differentiated treatment of packets in very 
   large scale environments. In contrast to the per-flow orientation of 
   Intserv and 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. At each Diffserv router, 
   packets are subjected to a "per-hop behavior" (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. 
    
   However, DiffServ does not include any mechanism for communication 
   between applications and the network. Thus, as detailed in [INT-
   DIFF], significant benefits can be achieved by using Intserv over 
   Diffserv including resource based admission control, policy based 
   admission control, assistance in traffic identification 
   /classification and traffic conditioning. As discussed in [INT-DIFF], 
   Intserv can operate over Diffserv in multiple ways. For example, the 
   Diffserv region may be statically provisioned or may be RSVP aware. 
   When it is RSVP aware, several mechanisms may be used to support 
   dynamic provisioning and topology aware admission control including 
 
 
Le Faucheur, et al.                                           [Page 2] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   aggregated RSVP reservations, per flow RSVP or a bandwidth broker. 
   The advantage of using aggregated RSVP reservations is that it offers 
   dynamic, topology-aware admission control over the Diffserv region 
   without the scalability burden of per-flow reservations and the 
   associated level of RSVP signaling in the Diffserv core. [RSVP-AGGR] 
   describes in details how to perform such aggregation of end to end 
   RSVP reservations over aggregated RSVP reservations in a Diffserv 
   cloud. It establishes an architecture where multiple end-to-end RSVP 
   reservations sharing the same ingress router (Aggregator) and the 
   same egress router (Deaggregator) at the edges of an "aggregation 
   region", can be mapped onto a single aggregate reservation within the 
   aggregation region. This considerably reduces the amount of 
   reservation state that needs to be maintained by routers within the 
   aggregation region. Furthermore, traffic belonging to aggregate 
   reservations is classified in the data path purely using Diffserv 
   marking. 
    
   [MPLS-TE] describes how MPLS TE Tunnels can be established via [RSVP-
   TE] and how these tunnels can be used to carry arbitrary aggregates 
   of traffic. MPLS TE uses Constraint Based Routing to compute the path 
   for a TE tunnel. Then, CAC (Call Admission Control) is performed 
   during the establishment of TE Tunnels to ensure they are granted 
   their requested resources. 
    
   [DSTE-REQ] presents the Service Providers requirements for support of 
   Diff-Serv-aware MPLS Traffic Engineering (DS-TE). With DS-TE, 
   separate DS-TE tunnels can be used to carry different Diffserv 
   classes of traffic and different resource constraints can be enforced 
   for these different classes. [DSTE-PROTO] specifies RSVP-TE signaling 
   extensions as well as OSPF and ISIS extensions for support of DS-TE. 
    
   In the rest of this document we will refer to both TE tunnels and DS-
   TE tunnels simply as "TE tunnels". 
    
   TE tunnels have much in common with the aggregate RSVP reservations 
   used in [RSVP-AGGR]:  
      - a TE tunnel is subject to CAC and thus is effectively an 
        aggregate bandwidth reservation 
      - In the data plane, packet scheduling relies exclusively on 
        Diff-Serv classification and PHBs 
      - Both TE tunnels and Aggregate RSVP reservations are controlled 
        by "intelligent" devices on the edge of the "aggregation core" 
        (Head-end and Tail-end in the case of TE tunnels, Aggregator 
        and Deaggregator in the case of Aggregated RSVP reservations 
      - Both TE tunnels and Aggregate RSVP reservations are signaled 
        using the RSVP protocol (with some extensions defined in [RSVP-
        TE] and [DSTE-PROTO] respectively for TE tunnels and DS-TE 
        tunnels). 
    
 
 
Le Faucheur, et al.                                           [Page 3] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   This document provides a detailed specification for performing 
   aggregation of end-to-end RSVP reservations over aggregated RSVP 
   reservations which are instantiated as MPLS TE tunnels. This document 
   builds on the RSVP Aggregation procedures defined in [RSVP-AGGR], and 
   only changes those where necessary to operate over TE tunnels. With 
   [RSVP-AGGR], a lot of responsibilities (such as mapping end-to-end 
   reservations to Aggregate reservations and resizing the Aggregate 
   reservations) are assigned to the Deaggregator (which is the 
   equivalent of the Tunnel Tail-end) while with TE, the tunnels are 
   controlled by the Tunnel Head-end. Hence, the main change over the 
   RSVP Aggregations procedures defined in [RSVP-AGGR] is to modify 
   these procedures to reassign responsibilities from the Deaggregator 
   to the Aggregator (i.e. the tunnel Head-end). 
    
   Aggregation of end-to-end RSVP reservations over TE tunnels combines 
   the benefits of [RSVP-AGGR] with the benefits of MPLS including the 
   following: 
      - dynamic, topology-aware resource-based admission control can be 
        provided to applications over any segment of the end to end 
        path including the core 
      - as per regular RSVP behavior, RSVP does not impose any burden 
        on routers where such admission control is not needed (for 
        example if the links upstream and downstream of the MPLS TE 
        core are vastly over-engineered compared to the core capacity, 
        admission control is not required on these links and RSVP need 
        not be processed on the corresponding router hops) 
      - the core scalability is not affected (relative to the standard 
        MPLS TE deployment model) since the core remains unaware of 
        end-to-end RSVP reservations and only has to maintain aggregate 
        TE tunnels and since the datapath classification and scheduling 
        in the core relies purely on Diffserv mechanism (or more 
        precisely MPLS Diffserv mechanisms as specified in [DIFF-MPLS])  
      - the aggregate reservation (and thus the traffic from the 
        corresponding end to end reservations) can be network 
        engineered via the use of Constraint based routing (e.g. 
        affinity, optimization on different metrics) and when needed 
        can take advantage of resources on other paths than the 
        shortest path 
      - the aggregate reservations (and thus the traffic from the 
        corresponding end to end reservations) can be protected against 
        failure through the use of MPLS Fast Reroute 
    
   This document, like [RSVP-AGGR], covers aggregation of unicast 
   sessions. Aggregation of multicast sessions is for further study. 
    
    
2.   
    Definitions 
    

 
 
Le Faucheur, et al.                                           [Page 4] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   For readability, a number of definitions from [RSVP-AGGR] as well as 
   definitions for commonly used MPLS TE terms are provided here: 
    
   Aggregator   This is the router at the ingress edge of the 
                 aggregation region (with respect to the end to end 
                 RSVP reservation) and behaving in accordance with 
                 [RSVP-AGG]. In this document, it is also the TE Tunnel 
                 Head-end. 
    
   Deaggregator This is the router at the egress edge of the 
                 aggregation region (with respect to the end to end 
                 RSVP reservation) and behaving in accordance with 
                 [RSVP-AGG]. In this document, it is also the TE Tunnel 
                 Tail-end 
    
   E2E          End to end 
    
   Head-end 
                 This is the Label Switch Router responsible for 
                 establishing, maintaining and tearing-off a given TE 
                 tunnel.  
    
   Tail-end 
                 This is the Label Switch Router responsible for 
                 terminating a given TE tunnel 
    
   Transit LSR  This is a Label Switch router which is on the path of 
                 a given TE tunnel and is neither the Head-end nor the 
                 Tail-end 
    
    
3.   
    Operations of RSVP Aggregation over TE with pre-established Tunnels 
    
   [RSVP-AGG] supports operations both in the case where aggregate RSVP 
   reservations are pre-established and in the case where Aggregating 
   and De-aggregating routers have to dynamically discover each other 
   and dynamically establish the necessary Aggregated RSVP reservations.  
    
   Similarly, RSVP Aggregation over TE tunnels could operate both in the 
   case where the TE tunnels are pre-established and in the case where 
   the tunnels need to be dynamically established. 
    
   In this section we provide a detailed description of the procedures 
   in the case where TE tunnels are already established. Procedures in 
   the case of dynamically established TE tunnels will be provided in 
   later versions of this document.  
 
3.1.   
      Reference Model 
    
      ------                                          ------ 
   H--I R  I\ -------                       -------- /I R  I--H 
 
 
Le Faucheur, et al.                                           [Page 5] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   H--I    I\\I     I       -----           I      I//I    I--H 
      -----I \I He/ I       I T I           I Te/  I/ ------ 
              I Agg I=======================I Deag I 
             /I     I       I   I           I      I\ 
   H--------//I     I       -----           I      I\\--------H 
   H--------/ -------                       -------- \--------H 
    
    
   H       = Host requesting end-to-end RSVP reservations 
   R       = RSVP router 
   He/Agg  = TE tunnel Head-end/Aggregator 
   Te/Deag = TE tunnel Tail-end/Deaggregator 
   T       = Transit LSR 
    
   /     = E2E RSVP reservation 
   ==    = TE Tunnel 
    
    
3.2.   
      Receipt of E2E Path message By the Aggregator 
    
   The first event is the arrival of the E2E Path message on the 
   Aggregator. Standard RSVP procedures are followed for this path 
   message (including update of the PHOP field to a local Aggregator 
   address) augmented with the extensions documented in this paragraph. 
    
   The Aggregator first attempts to map the E2E reservation onto a TE 
   tunnel. This decision is made in accordance with routing information 
   as well as any local policy information that may be available at the 
   Aggregator. Examples of such policies appear in the following 
   paragraphs. 
    
   There are situations where the Aggregator is able to make a final 
   mapping decision. That would be the case, for example, if there is a 
   single TE tunnel towards the destination and if the policy is to map 
   any E2E RSVP reservation onto TE Tunnels. 
    
   There are situations where the Aggregator is not able to make a final 
   determination. That would be the case, for example, if routing 
   identifies two DS-TE tunnels towards the destination, one belonging 
   to DS-TE Class-Type 1 and one to Class-Type 0, if the policy is to 
   map Intserv Guaranteed Services reservations to a Class-Type 1 tunnel 
   and Intserv Controlled Load reservations to a Class-Type 0 tunnel, 
   and if the E2E RSVP Path message advertises both Guaranteed Service 
   and Controlled Load.  
    
   Whether final or tentative, the Aggregator makes a mapping decision 
   and selects a TE tunnel. Before forwarding the E2E Path message 
   towards the receiver, the Aggregator should update the ADSPEC inside 
   the E2E Path message to reflect the impact of the MPLS TE cloud onto 
 
 
Le Faucheur, et al.                                           [Page 6] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   the QoS achievable by the E2E flow. This update is a local matter and 
   may be based on configured information, on information available in 
   the MPLS TE topology database, on the current TE tunnel path, on 
   information collected via RSVP-TE signaling, or combinations of 
   those. 
    
   The Aggregator then forwards the E2E Path message inside the TE 
   tunnel. Because the E2E Path message is encapsulated inside the TE 
   tunnel, it will not be processed by Transit routers along the path of 
   the TE tunnel. Thus, in contrast to the procedures of [RSVP-AGGR], 
   the IP Protocol number need not be modified to "RSVP-E2E-IGNORE"; it 
   is left as is to "RSVP". 
    
3.3.   
      Handling of E2E Path message By Transit LSRs 
    
   Since the E2E Path message is encapsulated inside the TE tunnel it is 
   hidden to all transit LSRs (except the Penultimate LSR when 
   Penultimate Hop Popping is used). 
    
   When Penultimate Hop Popping is used, the penultimate Router will pop 
   the tunnel label and, if no other label was imposed by the 
   Aggregator, the Path message will then be exposed. In this case, the 
   Penultimate Router must ignore the Path message. This may be ensured 
   via specific configuration of the Penultimate router. 
    
3.4.   
      Receipt of E2E Path Message by Deaggregator 
    
   The Deaggregator will either receive the E2E Path message directly as 
   an IP packet (when the Aggregator did not impose any other label 
   below the tunnel label and Penultimate Hop popping is used) or will 
   expose the E2E Path message after popping (in all the other cases). 
    
   On detection of the Router Alert, the Deaggregator will detect and 
   process the E2E Path message and ultimately forward it towards the 
   receiver. 
    
3.5.   
      Handling of E2E Resv Message by Deaggregator 
    
   Standard RSVP procedures are followed on receipt of the E2E Resv 
   message by the Deaggregator. This includes performing admission 
   control for the segment downstream of the Deaggregator and forwarding 
   the E2E Resv message to the PHOP signaled earlier in the E2E Path 
   message and which identifies the Aggregator. 
    
3.6.   
      Handling of E2E Resv Message by the Aggregator 
    
   The Aggregator is responsible for ensuring that there is sufficient 
   bandwidth available and reserved over the appropriate TE tunnel to 
   the Deaggregator for the E2E reservation. 
 
 
Le Faucheur, et al.                                           [Page 7] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
    
   On receipt of the E2E Resv message, the Aggregator first performs the 
   final mapping onto the final TE tunnels (if it was only a tentative 
   mapping). If needed the Aggregator updates the ADSPEC and immediately 
   generates an E2E Path refresh in order to provide the accurate ADSPEC 
   information to the receiver as soon as possible. 
   The aggregator then calculates the size of the resource request using 
   standard RSVP procedures. That is, it follows the procedures in 
   [RFC2205] to determine the resource requirements from the Sender 
   Tspec and the Flowspec contained in the Resv. It them compares the 
   resource requests with the available resources of the selected TE 
   tunnel. 
    
   If sufficient bandwidth is available on the final TE tunnel, the 
   Aggregator updates its internal understanding of how much of the TE 
   Tunnel is in use and forwards the E2E Resv messages to the 
   corresponding PHOP. 
    
   As noted in [RSVP-AGGR], a range of policies may be applied to the 
   re-sizing of the aggregate reservation (in this case, the TE tunnel.) 
   For example, the policy may be that the reserved bandwidth of the 
   tunnel can only be changed by configuration. More dynamic policies 
   are also possible, whereby the aggregator may attempt to increase the 
   reserved bandwidth of the tunnel in response to the amount of 
   allocated bandwidth that has been used by E2E reservations. 
   Furthermore, to avoid the delay associated with the increase of the 
   Tunnel size, the Aggregator may attempt to anticipate the increases 
   in demand and adjust the TE tunnel size ahead of actual needs by E2E 
   reservations. 
    
   If sufficient bandwidth is not available on the final TE Tunnel, the 
   Aggregator must follow the normal RSVP procedure for a reservation 
   being placed with insufficient bandwidth to support this reservation. 
   That is, the reservation is not installed and a ResvError is sent 
   back towards the receiver.  
 
3.7.   
      Removal of E2E reservations  
    
   E2E reservations are removed in the usual way via PathTear, ResvTear, 
   timeout, or as the result of an error condition. When a reservation 
   is removed, the Aggregator updates its local view of the  
   resources available on the corresponding TE tunnel accordingly. 
    
3.8.   
      Removal of TE Tunnel 
    
   Should a TE Tunnel go away (presumably due to a configuration change, 
   route change, or policy event), the aggregator behaves much like a 
   conventional RSVP router in the face of a link failure. That is, it 
   may try to forward the Path messages onto another tunnel, if routing 
 
 
Le Faucheur, et al.                                           [Page 8] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   and policy permit, or it may send Path_Error messages to the sender 
   if no suitable tunnel exists. In case the Path messages are forwarded 
   onto another tunnel which terminates on a different Deaggregator, or 
   the reservation is torn-down via Path Error messages, the reservation 
   state established on the router acting as the Deaggregator before the 
   TE tunnel went away, will time out since it will no longer be 
   refreshed. 
    
3.9.   
      Example Signaling Flow 
    
    
                Aggregator                      Deaggregator 
    
       E2E Path 
      --------------> 
                   (1) 
                              E2E Path 
                     ===============================> 
                                                    (2) 
                                                        E2E Path 
                                                        -----------> 
    
                                                            E2E Resv 
                                                        <----------- 
                                                     (3) 
                              E2E Resv 
                      <----------------------------- 
                   (4) 
          E2E Resv 
      <------------- 
    
    
      (1)  Aggregator tentatively selects the TE tunnel and forwards 
           E2E path inside TE Tunnel 
       
      (2)  Deaggregator forwards the E2E Path towards receiver 
 
      (3)  Deaggregator forwards the E2E Resv to the Aggregator 
 
      (4)  Aggregator selects final TE tunnel, check there is 
           sufficient bandwidth on TE tunnel and forwards E2E Resv to 
           PHOP 
    
 
4.   
    IPv4 and IPv6 Applicability 
    
   The procedures defined in this document are applicable to all the 
   following cases: 
    
 
 
Le Faucheur, et al.                                           [Page 9] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
      (1)  Aggregation of E2E IPv4 RSVP reservations over IPv4 TE 
           Tunnels 
      (2)  Aggregation of E2E IPv6 RSVP reservations over IPv6 TE 
           Tunnels 
      (3)  Aggregation of E2E IPv6 RSVP reservations over IPv4 TE 
           tunnels, provided a mechanism such as [6PE] is used by the 
           Aggregator and Deaggregator for routing of IPv6 traffic over 
           an IPv4 MPLS core,  
      (4)  Aggregation of E2E IPv4 RSVP reservations over IPv6 TE 
           tunnels, provided a mechanism is used by the Aggregator and 
           Deaggregator for routing IPv4 traffic over IPv6 MPLS. 
    
    
5.   
    E2E Reservations Applicability 
    
   The procedures defined in this document are applicable to many types 
   of E2E RSVP reservations including the following cases: 
      (1)  the E2E RSVP reservation is a per-flow reservation where the 
           flow is characterized by the usual 5-tuple 
      (2)  the E2E reservation is an aggregate reservation for multiple 
           flows as described in [RSVP-AGG] where the set of flows is 
           characterized by the <source address, destination address, 
           DSCP>  
      (3)  the E2E reservation is a reservation for an IPSec protected 
           flow. For example, where the flow is characterized by the 
           <source address, destination address, SPI> as described in 
           [RSVP-IPSEC] 
      (4)  the E2E reservation is an aggregate reservation for multiple 
           flows and where the set of flows are protected by IPSec 
      (5)  the E2E RSVP reservation is itself an RSVP-TE reservation 
           for an E2E TE tunnel, so that LSP Hierarchy is achieved 
           [LSP-HIER] 
 
 
6.   
    Example Deployment Scenarios 
    
6.1.   
      Voice and Video Reservations Scenario 
    
   An example application of the procedures specified in this document 
   is admission control of voice and video in environments with very 
   high numbers of hosts. In the example illustrated below, hosts 
   generate end-to-end per-flow reservations for each of their video 
   streams associated with a video-conference, each of their audio 
   streams associated with a video-conference and each of their voice 
   calls. These reservations are aggregated over MPLS DS-TE tunnels over 
   the packet core. The mapping policy defined by the user maybe that 
   all the reservations for audio and voice streams are mapped onto DS-
   TE tunnels of Class-Type 1 while reservations for video streams are 
   mapped onto DS-TE tunnels of Class-Type 0. 
 
 
Le Faucheur, et al.                                          [Page 10] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
    
   ------                                             ------ 
   I H  I# -------                          -------- #I H  I 
   I    I\#I     I          -----           I      I#/I    I 
   -----I \I Agg I          I T I           I Deag I/ ------ 
           I     I==========================I      I 
   ------ /I     I::::::::::I   I:::::::::::I      I\ ------ 
   I H  I/#I     I          -----           I      I#\I H  I 
   I    I# -------                          -------- #I    I 
   ------                                             ------ 
    
   H     = Host 
   Agg   = Aggregator (TE Tunnel Head-end) 
   Deagg = Deaggregator (TE Tunnel Tail-end) 
   T     = Transit LSR 
    
   /     = E2E RSVP reservation for a Voice flow 
   #     = E2E RSVP reservation for a Video flow 
   ==    = DS-TE Tunnel from Class-Type 1 
   ::    = DS-TE Tunnel from Class-Type 0 
 
    
6.2.   
      PSTN/3G Voice Trunking Scenario 
    
   An example application of the procedures specified in this document 
   is voice call admission control in large scale telephony trunking 
   environments. A Trunk VoIP Gateway may generate one aggregate RSVP 
   reservation for all the calls in place towards another given remote 
   Trunk VoIP Gateway (with resizing of this aggregate reservation in a 
   step function depending on current number of calls). In turn, these 
   reservations may be aggregated over MPLS TE tunnels over the packet 
   core so that tunnel Head-ends act as Aggregators and perform 
   admission control of Trunk Gateway reservations into MPLS TE Tunnels.  
   The MPLS TE tunnels may be protected by MPLS Fast Reroute. 
   This scenario is illustrated below: 
    
   ------                                             ------ 
   I GW I\ -------                          -------- /I GW I 
   I    I\\I     I          -----           I      I//I    I 
   -----I \I Agg I          I T I           I Deag I/ ------ 
           I     I==========================I      I 
   ------ /I     I          I   I           I      I\ ------ 
   I GW I//I     I          -----           I      I\\I GW I 
   I    I/ -------                          -------- \I    I 
   ------                                             ------ 
    
   GW    = VoIP Gateway 
   Agg   = Aggregator (TE Tunnel Head-end) 
   Deagg = Deaggregator (TE Tunnel Tail-end) 
 
 
Le Faucheur, et al.                                          [Page 11] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   T     = Transit LSR 
    
   /     = Aggregate Gateway to Gateway E2E RSVP reservation 
   ==    = TE Tunnel 
    
    
7.   
    Security Considerations 
    
   The security issues inherent to the use of RSVP, RSVP Aggregation and 
   MPLS TE apply. Those can be addressed as discussed in [RSVP], [RSVP-
   AGG] and [RSVP-TE]. 
    
   In addition, in the case where the Aggregators dynamically resize the 
   TE tunnels based on the current level of reservation, there are risks 
   that the TE tunnels used for RSVP aggregation hog resources in the 
   core which could prevent other TE Tunnels from being established. 
   There are also potential risks that such resizing results in 
   significant computation and signaling as well as churn on tunnel 
   paths. Such risks can be mitigated by configuration options allowing 
   control of TE tunnel dynamic resizing (maximum Te tunnel size, 
   maximum resizing frequency,...) and/or possibly by the use of TE 
   preemption. 
    
    
8.   
    Acknowledgments 
    
   This document builds on the [RSVP-AGGR] and [RSVP-TUN] 
   specifications. 
    
    
9.   
    Normative References 
    
   [RFC2119] S. Bradner, Key words for use in RFCs to Indicate 
   Requirement Levels, RFC2119, March 1997. 
    
   RFC 3668 S. Bradner, Intellectual Property Rights in IETF 
   Technology, RFC 3668, February 2004. 
    
   BCP 78, S. Bradner, IETF Rights in Contributions, RFC 3667, February 
   2004. 
    
   [INT-SERV] Braden, R., Clark, D. and S. Shenker, "Integrated Services 
   in the Internet Architecture: an Overview", RFC 1633, June 1994. 
    
   [GUARANTEED] Shenker et al., Specification of Guaranteed Quality of 
   Service, RFC2212 
    
   [CONTROLLED] Wroclawski, Specification of the Controlled-Load Network 
   Element Service, RFC2211 
 
 
Le Faucheur, et al.                                          [Page 12] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
    
   [DIFFSERV] Blake et al., "An Architecture for Differentiated 
   Services", RFC 2475 
    
   [INT-DIFF] A Framework for Integrated Services Operation over 
   Diffserv Networks, RFC 2998, November 2000. 
    
   [RSVP-AGGR] Baker et al, Aggregation of RSVP for IPv4 and IPv6 
   Reservations, RFC 3175, September 2001. 
    
   [DSTE-REQ] Le Faucheur et al, Requirements for support of Diff-Serv-
   aware MPLS Traffic Engineering, draft-ietf-tewg-diff-te-reqts-07.txt, 
   February 2003. 
    
   [DSTE-PROTO] Le Faucheur et al, Protocol extensions for support of 
   Diff-Serv-aware MPLS Traffic Engineering, draft-ietf-tewg-diff-te-
   proto-04.txt, June 2003 
    
    
10.   
     Informative References 
    
   [RSVP-TE] Awduche et al, "RSVP-TE: Extensions to RSVP for LSP 
   Tunnels", RFC 3209, December 2001. 
    
   [DIFF-MPLS] Le Faucheur et al, "MPLS Support of Diff-Serv", RFC3270, 
   May 2002. 
    
   [6PE] De Clercq et al, "Connecting IPv6 Islands over IPv4 MPLS using 
   IPv6 Provider Edge Routers (6PE)", work in progress 
    
   [LSP-HIER] Kompella et al, "LSP Hierarchy with Generalized MPLS TE", 
   work in progress 
    
   [RSVP-IPSEC] Berger et al, "RSVP Extensions for IPSEC Data Flows", 
   RFC 2207 
    
   [RSVP-TUN] Terzis et al. "RSVP Operation Over IP Tunnels", RFC 2746, 
   January 2000 
    
    
11.   
     Copyright Notice 
    
   Copyright (C) The Internet Society (2004).  This document is subject 
   to the rights, licenses and restrictions contained in BCP 78, and 
   except as set forth therein, the authors retain all their rights. 
    
   This document and the information contained herein are provided on an 
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 
   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 
 
 
Le Faucheur, et al.                                          [Page 13] 

                RSVP Aggregation over MPLS TE tunnels       July 2004 
 
 
   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 
   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 
   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 
    
    
12.   
     Authors Address: 
    
   Francois Le Faucheur 
   Cisco Systems, Inc. 
   Village d'Entreprise Green Side - Batiment T3 
   400, Avenue de Roumanille 
   06410 Biot Sophia-Antipolis 
   France 
   Email: flefauch@cisco.com 
    
    
   Michael DiBiasio 
   Cisco Systems, Inc. 
   300 Beaver Brook Road 
   Boxborough, MA 01719  
   USA 
   Email: dibiasio@cisco.com 
    
    
   Bruce Davie 
   Cisco Systems, Inc. 
   300 Beaver Brook Road 
   Boxborough, MA 01719  
   USA 
   Email: bdavie@cisco.com 
    
        
   Christou Christou 
   Booz Allen Hamilton 
   8283 Greensboro Drive 
   McLean, VA 22102 
   USA 
    
    
   Michael Davenport 
   Booz Allen Hamilton 
   8283 Greensboro Drive 
   McLean, VA 22102 
   USA 




 
 
Le Faucheur, et al.                                          [Page 14] 


PAFTECH AB 2003-20262026-04-22 09:27:22