One document matched: draft-ietf-ccamp-gmpls-mln-eval-04.txt

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Network Working Group                                 J.L. Le Roux (Ed.)  
Internet Draft                                            France Telecom 
Category: Informational                                     
Expires: May 2008                                D.  Papadimitriou (Ed.)  
                                                          Alcatel-Lucent 
                                                       
                                                  
                                                         
                                                                         
                                                                         
                                                           November 2007 
 
 
        Evaluation of existing GMPLS Protocols against Multi Layer 
                    and Multi Region Networks (MLN/MRN) 
 
               draft-ietf-ccamp-gmpls-mln-eval-04.txt 
         
 
 
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Abstract 
    
   This document provides an evaluation of Generalized Multi-Protocol 
   Label Switching (GMPLS) protocols and mechanisms against the 
   requirements for Multi-Layer Networks (MLN) and Multi-Region Networks 
   (MRN). In addition, this document identifies areas where additional 
   protocol extensions or procedures are needed to satisfy these 
   requirements, and provides guidelines for potential extensions. 
 
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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. 
 
Table of Contents 
    
   1.      Introduction................................................3 
   2.      MLN/MRN Requirements Overview...............................4 
   3.      Analysis....................................................4 
   3.1.    Multi Layer Network Aspects.................................4 
   3.1.1.  Support for Virtual Network Topology Reconfiguration........4 
   3.1.1.1.  Control of FA-LSPs Setup/Release..........................5 
   3.1.1.2.  Virtual TE-Links..........................................6 
   3.1.1.3.  Traffic Disruption Minimization During FA Release.........7 
   3.1.1.4.  Stability.................................................7 
   3.1.2.  Support for FA-LSP Attributes Inheritance...................8 
   3.1.3.  FA-LSP Connectivity Verification............................8 
   3.2.    Specific Aspects for Multi-Region Networks..................8 
   3.2.1.  Support for Multi-Region Signaling..........................8 
   3.2.2.  Advertisement of Adjustment Capacities......................9 
   4.      Evaluation Conclusion......................................12 
   5.      Security Considerations....................................12 
   6.      Acknowledgments............................................13 
   7.      References.................................................13 
   7.1.    Normative..................................................13 
   7.2.    Informative................................................13 
   8.      Editors' Addresses:........................................14 
   9.      Contributors' Addresses:...................................14 
   10.     Intellectual Property Statement............................15 
    
    
    
    
    
    
    
    
    
    
    
    
    
 
 
 
 
 
 
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1. Introduction 
 
   Generalized MPLS (GMPLS) extends MPLS to handle multiple switching 
   technologies: packet switching, layer-2 switching, TDM switching, 
   wavelength switching, and fiber switching (see [RFC3945]). The 
   Interface Switching Capability (ISC) concept is introduced for 
   these switching technologies and is designated as follows: PSC 
   (Packet Switch Capable), L2SC (Layer-2 Switch Capable), TDM (Time 
   Division Multiplex capable), LSC (Lambda Switch Capable), and FSC 
   (Fiber Switch Capable). The representation, in a GMPLS control  
   plane, of a switching technology domain is referred to as a region  
   [RFC4206]. A switching type describes the ability of a node to  
   forward data of a particular data plane technology, and uniquely  
   identifies a network region. 
    
   A data plane switching layer describes a data plane switching 
   granularity level. For example, LSC, TDM VC-11 and TDM VC-4-64c are 
   three different layers.  [MLN-REQ] defines a Multi Layer Network (MLN)  
   to be a TE domain comprising multiple data plane switching layers  
   either of the same ISC (e.g. TDM) or different ISC (e.g. TDM and  
   PSC) and controlled by a single GMPLS control plane instance. 
   [MLN-REQ] further define a particular case of MLNs. A Multi Region 
   Network (MRN) is defined as a TE domain supporting at least two 
   different switching types (e.g., PSC and TDM), either hosted on the 
   same device or on different ones, and under the control of a single 
   GMPLS control plane instance. 
 
   The objectives of this document are to evaluate existing GMPLS 
   mechanisms and protocols ([RFC 3945], [RFC4202], [RFC3471, 
   [RFC3473]]) against the requirements for MLN and MRN, defined in 
   [MLN-REQ]. From this evaluation, we identify several areas where 
   additional protocol extensions and modifications are required to meet 
   these requirements, and provide guidelines for potential extensions. 
    
   A summary of MLN/MRN requirements is provided in section 2. Then 
   section 3 evaluates for each of these requirements, whether current 
   GMPLS protocols and mechanisms meet the requirements. When the 
   requirements are not met by existing protocols, the document 
   identifies whether the required mechanisms could rely on GMPLS 
   protocols and procedure extensions or whether it is entirely out of 
   the scope of GMPLS protocols. 
    
   Note that this document specifically addresses GMPLS control plane   
   functionality for MLN/MRN in the context of a single administrative 
   control plane partition. Partitions of the control plane where 
   separate layers are under distinct administrative control are for 
   future study. 
    
   This document uses terminologies defined in [RFC3945], [RFC4206], and   
   [MLN-REQ].  
    
 
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2. MLN/MRN Requirements Overview 
 
   Section 5 of [MLN-REQ] lists a set of functional requirements for 
   Multi Layer/Region Networks (MLN/MRN). These requirements are 
   summarized below, and a mapping with sub-sections of [MLN-REQ] is 
   provided. 
    
   Here is the list of requirements that apply to MLN (and thus to MRN): 
    
        - Support for robust Virtual Network Topology (VNT)   
          reconfiguration. This implies the following requirements: 
                - Optimal control of Forwarding Adjacency LSP (FA-LSP)   
                  setup and release (section  5.8.1 of [MLN-REQ]); 
                - Support for virtual TE-links (section 5.8.2 of [MLN- 
                  REQ]); 
                - Traffic Disruption minimization during FA-LSP release  
                  (section 5.5 of [MLN-REQ]); 
                - Stability (section 5.4 of [MLN-REQ]); 
    
        - Support for FA-LSP attributes inheritance (section 5.6 of  
          [MLN-REQ]); 
 
        - Support for FA-LSP data plane connectivity verification   
          (section 5.9 of [MLN-REQ]); 
         
   Here is the list of requirements that apply to MRN only: 
 
        - Support for Multi-Region signaling (section 5.7 of [MLN-REQ]); 
 
        - Advertisement of the adjustment capacity (section 5.2 of 
           [MLN-REQ]); 
    
3. Analysis 
 
3.1. Multi Layer Network Aspects 
    
3.1.1. Support for Virtual Network Topology Reconfiguration 
 
   A set of lower-layer FA-LSPs provides a Virtual Network Topology 
   (VNT) to the upper-layer [MLN-REQ]. By reconfiguring the VNT (FA-LSP 
   setup/release) according to traffic demands between source and 
   destination node pairs within a layer, network performance factors 
   such as maximum link utilization and residual capacity of the network 
   can be optimized. Such optimal VNT reconfiguration implies several 
   mechanisms that are analyzed in the following sections. 
    
   Note that the VNT approach is just one possible approach to perform 
   inter-layer Traffic Engineering.   
    
    
 
 
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3.1.1.1. Control of FA-LSPs Setup/Release 
         
   In a Multi-Layer Network, FA-LSPs are created, modified, released 
   periodically according to the change of incoming traffic demands from 
   the upper layer. 
    
   This implies a TE mechanism that takes into account the demands  
   matrix, the TE topology and potentially the current VNT, in order to 
   compute and setup a new VNT.  
 
   Several functional building blocks are required to support such TE 
   mechanism: 
    
        - Discovery of TE topology and available resources. 
    
        - Collection of upper layer traffic demands.  
    
        - Policing and scheduling of VNT resources with regard to  
          traffic demands and usage (that is, decision to setup/release  
          FA-LSPs); The functional component in charge of this function  
          is called a VNT Manager (VNTM).  
    
        - VNT Paths Computation according to TE topology, and  
          potentially taking into account the old (existing) VNT to  
          minimize changes. The Functional component in charge of VNT  
          computation may be distributed on network elements or may be  
          performed on an external tool (such as a Path Computation  
          Element (PCE), [RFC4655]). 
    
        - FA-LSP setup/release. 
    
   GMPLS routing protocols provide TE topology discovery.  
   GMPLS signaling protocols allow setting up/releasing FA-LSPs. 
 
   VNTM functions (resources policing/scheduling, decision to 
   setup/release FA-LSPs, FA-LSP configuration) are out of the scope of 
   GMPLS protocols. Such functionalities can be achieved directly on 
   layer border LSRs, or through one or more external tools. When an 
   external tool is used, an interface is required between the VNTM and 
   the network elements so as to setup/release FA-LSPs. This could use 
   standard management interfaces such as [RFC4802]. 
    
   The set of traffic demands of the upper layer is required for the     
   VNT Manager to take decisions to setup/release FA-LSPs. Such 
   traffic demands include satisfied demands, for which one or more 
   upper layer LSP have been successfully setup, as well as unsatisfied 
   demands and future demands, for which no upper layer LSP has been 
   setup yet. The collection of such information is beyond the scope of 
   GMPLS protocols. Note that it may be partially inferred from 
   parameters carried in GMPLS signalling or advertised in GMPLS routing. 
    

 
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   Finally, the computation of FA-LSPs that form the VNT can be 
   performed directly on layer border LSRs or on an external tool (such 
   as a Path Computation Element (PCE), [RFC4655]), and this is 
   independent of the location of the VNTM.  
    
   Hence, to summarize, no GMPLS protocol extensions are required to 
   control FA-LSP setup/release. 
 
3.1.1.2. Virtual TE-Links 
         
   A Virtual TE-link is a TE-link between two upper layer nodes that is 
   not actually associated with a fully provisioned FA-LSP in a lower 
   layer. A Virtual TE-link represents the potentiality to setup an FA-
   LSP in the lower layer to support the TE-link that has been 
   advertised. A Virtual TE-link is advertised as any TE-link, following 
   the rules in [RFC4206] defined for fully provisioned TE-links. In 
   particular, the flooding scope of a Virtual TE-link is within an IGP 
   area, as is the case for any TE-link. 
     
   If an upper-layer LSP attempts (through a signalling message) to make 
   use of a Virtual TE-link, the underlying FA-LSP is immediately 
   signalled and provisioned (provided there are available resources in 
   the lower layer) in the process known as triggered signaling. 
    
   The use of Virtual TE-links has two main advantages: 
    
     - Flexibility: allows the computation of an LSP path using TE-links  
       without needing to take into account the actual provisioning  
       status of the corresponding FA-LSP in the lower layer; 
     
     - Stability: allows stability of TE-links in the upper layer, while  
       avoiding wastage of bandwidth in the lower layer, as data plane  
       connections are not established until they are actually needed. 
    
   Virtual TE-links are setup/deleted/modified dynamically, according to 
   the change of the (forecast) traffic demand, operator's policies for 
   capacity utilization, and the available resources in the lower layer. 
    
   The support of Virtual TE-links requires two main building blocks: 
    
   - A TE mechanism for dynamic modification of Virtual TE-link    
     Topology; 
    
   - A signaling mechanism for the dynamic setup and deletion of 
     virtual TE-links. Setting up a virtual TE-link requires a  
     signaling mechanism allowing an end-to-end association  
     between Virtual TE-link end points so as to exchange link   
     identifiers as well as some TE parameters. 
    
   The TE mechanism responsible for triggering/policing dynamic 
   modification of Virtual TE-links is out of the scope of GMPLS 
   protocols. 
 
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   Current GMPLS signalling does not allow setting up and releasing 
   Virtual TE-links. Hence GMPLS signalling must be extended to support 
   Virtual TE-links.  
 
   We can distinguish two options for setting up Virtual TE-links: 
    
   - The Soft FA approach that consists of setting up the FA-LSP in the   
     control plane without actually activating cross connections in the    
     data plane. On the one hand, this requires state maintenance on all    
     transit LSRs (N square issue), but on the other hand this may allow    
     for some admission control. Indeed, when a soft-FA is activated,   
     the resources may be no longer available for use by other soft-FAs  
     that have common links. These soft-FA will be dynamically released  
     and corresponding virtual TE-links are deleted. The soft-FA LSPs  
     may be setup using procedures similar to those described in  
     [RFC4872] for setting up secondary LSPs. 
    
   - The remote association approach that simply consists of exchanging  
      virtual TE-links IDs and parameters directly between TE-link end   
      points. This does not require state maintenance on transit LSRs,  
      but reduces admission control capabilities. Such an association  
      between Virtual TE-link end-points may rely on extensions to the  
      RSVP-TE ASON Call procedure ([RSVP-CALL]). 
    
   Note that the support of Virtual TE-links does not require any GMPLS 
   routing extension. 
 
3.1.1.3. Traffic Disruption Minimization During FA Release 
 
   Before deleting a given FA-LSP, all nested LSPs have to be rerouted 
   and removed from the FA-LSP to avoid traffic disruption. 
   The mechanisms required here are similar to those required for 
   graceful deletion of a TE-Link. A Graceful TE-link deletion mechanism 
   allows for the deletion of a TE-link without disrupting traffic of 
   TE-LSPs that were using the TE-link. 
    
   Hence, GMPLS routing and/or signaling extensions are required 
   to support graceful deletion of TE-links. This may utilize the 
   procedures described in [GR-SHUT]: A transit LSR notifies a head-end 
   LSR that a TE-link along the path of a LSP is going to be torn down, 
   and also withdraws the bandwidth on the TE-link so that it is not 
   used for new LSPs. 
 
3.1.1.4. Stability 
         
   The stability of upper-layer LSP may be impaired if the VNT undergoes 
   frequent changes. In this context robustness of the VNT is defined as 
   the capability to smooth the impact of these changes and avoid their 
   subsequent propagation. 
    

 
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   Guaranteeing VNT stability is out of the scope of GMPLS protocols and 
   relies entirely on the capability of the TE and VNT management 
   algorithms to minimize routing perturbations. This requires that the 
   algorithms takes into account the old VNT when computing a new VNT, 
   and try to minimize the perturbation. 
    
   Note that a full mesh of lower-layer LSPs may be created between 
   every pair of border nodes between the upper and lower layers. The 
   merit of a full mesh of lower-layer LSPs is that it provides 
   stability to the upper layer routing. That is, forwarding table used 
   in the upper layer is not impacted if the VNT undergoes changes. 
   Further, there is always full reachability and immediate access to 
   bandwidth to support LSPs in the upper layer. But it also has 
   significant drawbacks, since it requires the maintenance of n^2 RSVP-
   TE sessions, which may be quite CPU and memory consuming (scalability 
   impact). Also this may lead to significant bandwidth wastage. Note 
   that the use of virtual TE-links solves the bandwidth wastage issue, 
   and may reduce the control plane overload. 
    
  
3.1.2. Support for FA-LSP Attributes Inheritance 
 
   When a FA TE Link is advertised, its parameters are inherited from 
   the parameters of the FA-LSP, and specific inheritance rules are 
   applied.  
    
   This relies on local procedures and policies and is out of the scope 
   of GMPLS protocols. Note that this requires that both head-end and 
   tail-end of the FA-LSP are driven by same policies. 
    
3.1.3. FA-LSP Connectivity Verification 
 
   Once fully provisioned, FA-LSP liveliness may be achieved by 
   verifying its data plane connectivity. 
    
   FA-LSP connectivity verification relies on technology specific 
   mechanisms (e.g., for SDH using G.707 and G.783; for MPLS using BFD; 
   etc.) as for any other LSP. Hence this requirement is out of the 
   scope of GMPLS protocols. 
 
 
3.2. Specific Aspects for Multi-Region Networks 
    
3.2.1. Support for Multi-Region Signaling 
    
   There are actually several cases where a transit node could choose 
   between multiple SCs to be used for a lower region FA-LSP:  
    
   - ERO expansion with loose hops: The transit node has to expand the  
     path, and may have to select among a set of lower region SCs. 
   
   - Multi-SC TE link: When the ERO of a FA LSP, included in the ERO of  
 
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     an upper region LSP, comprises a multi-SC TE-link, the region  
     border node has to select among these SCs. 
           
   Existing GMPLS signalling procedures do not allow solving this 
   ambiguous choice of SC that may be used along a given path. 
     
   Hence an extension to GMPLS signalling has to be defined to indicate 
   the SC(s) that can be used and the SC(s) that cannot be used along 
   the path.  
 
3.2.2. Advertisement of Adjustment Capacities 
 
   In the MRN context, nodes supporting more than one switching 
   capability on at least one interface are called Hybrid nodes ([MLN-
   REQ]). Conceptually, hybrid nodes can be viewed as containing at 
   least two distinct switching elements interconnected by internal 
   links which provide adjustment between the supported switching 
   capabilities. These internal links have finite capacities and must be 
   taken into account when computing the path of a multi-region TE-LSP. 
   The advertisement of the adjustment capacities is required as it 
   provides critical information when performing multi-region path 
   computation. 
    
   The term adjustment capacity refers to the property of a hybrid node 
   to interconnect different switching capabilities it provides though 
   its external interfaces [MLN-REQ]. This information allows path 
   computation to select an end-to-end multi-region path that includes 
   links of different switching capabilities that are joined by LSRs 
   that can adapt the signal between the links. 
    
 
   Figure 1a below shows an example of hybrid node. The hybrid node has 
   two switching elements (matrices), which support here TDM and PSC 
   switching respectively. The node has two PSC and TDM ports (port1 and 
   port2 respectively). It also has internal link connecting the two 
   switching elements.  
    
   The two switching elements are internally interconnected in such a 
   way that it is possible to terminate some of the resources of the TDM 
   port 2 and provide through them adjustment for PSC traffic, 
   received/sent over the internal PSC interface (#b). Two ways are 
   possible to set up PSC LSPs (port 1 or port 2). Available resources 
   advertisement e.g. Unreserved and Min/Max LSP Bandwidth should cover 
   both ways. 
    
    
    
    
    
    
    
 
 
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                             Network element  
                        .............................  
                        :            --------       :  
              PSC       :           |  PSC   |      :  
            Port1-------------<->---|#a      |      :  
                        :  +--<->---|#b      |      :  
                        :  |         --------       :  
                        :  |        ----------      :  
              TDM       :  +--<->--|#c  TDM   |     :  
            Port2 ------------<->--|#d        |     :  
                        :           ----------      :  
                        :............................  
    
                             Figure 1a. Hybrid node.  
 
 
 
   Port 1 and Port 2 can be grouped together thanks to internal DWDM, to 
   result in a single interface: Link 1. This is illustrated in figure 
   1b below. 
    
                             Network element  
                        .............................  
                        :            --------       :  
                        :           |  PSC   |      :  
                        :           |        |      :  
                        :         --|#a      |      :  
                        :        |  |   #b   |      :  
                        :        |   --------       :  
                        :        |       |          :  
                        :        |  ----------      :  
                        :    /|  | |    #c    |     :  
                        :   | |--  |          |     :  
              Link1 ========| |    |    TDM   |     :  
                        :   | |----|#d        |     :  
                        :    \|     ----------      :  
                        :............................  
    
                        Figure 1b. Hybrid node.  
    
    
   Let's assume that all interfaces are STM16 (with VC4-16c capable  
   as Max LSP bandwidth). After, setting up several PSC LSPs via port #a 
   and setting up and terminating several TDM LSPs via port #d and port 
   #b, there is only 155 Mb capacities still available on port #b. 
   However a 622 Mb capacity remains on port #a and VC4-5c capacity on 
   port #d. 
    
   When computing the path for a new VC4-4c TDM LSP, one must know, that 
   this node cannot terminate this LSP, as there is only 155Mb still 
   available for TDM-PSC adjustment. Hence the TDM-PSC adjustment 
   capacity must be advertised. 
 
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   With current GMPLS routing [RFC4202] this advertisement is possible 
   if link bundling is not used and if two TE-links are advertised for 
   link1: 
    
   We would have the following TE-link advertisements: 
    
   TE-link 1 (port 1):  
        - ISCD sub-TLV: PSC with Max LSP bandwidth = 622Mb 
        - Unreserved bandwidth = 622Mb. 
          
   TE-Link 2 (port 2): 
        - ISCD #1 sub-TLV: TDM with Max LSP bandwidth = VC4-4c,               
        - ISCD #2 sub-TLV: PSC with Max LSP bandwidth = 155 Mb, 
        - Unreserved bandwidth (equivalent): 777 Mb.  
    
   The ISCD 2 in TE-link 2 represents actually the TDM-PSC adjustment 
   capacity. 
    
   However if for obvious scalability reasons link bundling is done then 
   the adjustment capacity information is lost with current GMPLS 
   routing, as we have the following TE-link advertisement: 
    
   TE-link 1 (port 1 + port 2):  
        - ISCD #1 sub-TLV: TDM with Max LSP bandwidth = VC4-4c,  
        - ISCD #2 sub-TLV: PSC with Max LSP bandwidth = 622 Mb,  
        - Unreserved bandwidth (equivalent): 1399 Mb.  
     
   With such TE-link advertisement an element computing the path of a 
   VC4-4c LSP cannot know that this LSP cannot be terminated on the 
   node. 
    
   Thus current GMPLS routing can support the advertisement of the 
   adjustment capacities but this precludes performing link bundling and 
   thus faces significant scalability limitations.  
    
   Hence, GMPLS routing must be extended to meet this requirement. This 
   could rely on the advertisement of the adjustment capacities as a new 
   TE link attribute (that would complement the Interface Switching 
   Capability Descriptor TE-link attribute).  
    
   Note: Multiple ISCDs MAY be associated to a single switching 
   capability. This can be performed to provide e.g. for TDM interfaces 
   the Min/Max LSP Bandwidth associated to each (set of) layer for that 
   switching capability. As an example, an interface associated to TDM 
   switching capability and supporting VC-12 and VC-4 switching, can be 
   associated one ISCD sub-TLV or two ISCD sub-TLVs. In the first case, 
   the Min LSP Bandwidth is set to VC-12 and the Max LSP Bandwidth to 
   VC-4. In the second case, the Min LSP Bandwidth is set to VC-12 and 
   the Max LSP Bandwidth to VC-12, in the first ISCD sub-TLV; and the 
   Min LSP Bandwidth is set to VC-4 and the Max LSP Bandwidth to VC-4, 
   in the second ISCD sub-TLV. Hence, in the first case, as long as the 
 
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   Min LSP Bandwidth is set to VC-12 (and not VC-4) and in the second 
   case, as long as the first ISCD sub-TLV is advertised there is 
   sufficient capacity across that interface to setup a VC-12 LSP. 
    
 
4. Evaluation Conclusion 
 
   Most of the required MLN/MRN functions will rely on mechanisms and 
   procedures that are out of the scope of the GMPLS protocols, and thus 
   do not require any GMPLS protocol extensions. They will rely on local 
   procedures and policies, and on specific TE mechanisms and 
   algorithms. 
    
   As regards Virtual Network Topology (VNT) computation and 
   reconfiguration, specific TE mechanisms need to be defined, but these 
   mechanisms are out of the scope of GMPLS protocols. 
    
   Four areas for extensions of GMPLS protocols and procedures have been 
   identified: 
    
        - GMPLS signaling extension for the setup/deletion of    
          the virtual TE-links; 
    
        - GMPLS routing and signaling extension for graceful TE-link  
          deletion; 
 
        - GMPLS signaling extension for constrained multi-region  
          signalling (SC inclusion/exclusion); 
    
        - GMPLS routing extension for the advertisement of the  
          adjustment capacities of hybrid nodes. 
    
5. Security Considerations 
    
   [MLN-REQ] sets out the security requirements for operating a MLN or 
   MRN. These requirements are, in general, no different from the 
   security requirements for operating any GMPLS network. As such, the 
   GMPLS protocols already provide adequate security features. An 
   evaluation of the security features for GMPLS networks may be found 
   in [MPLS-SEC], and where issues or further work is identified by that 
   document, new security features or procedures for the GMPLS protocols 
   will need to be developed. 
    
   [MLN-REQ] also identifies that where the separate layers of a MLN/MRN 
   network are operated as different administrative domains, additional 
   security considerations may be given to the mechanisms for allowing 
   inter-layer LSP setup. However, this document is explicitly limited 
   to the case where all layers under GMPLS control are part of the same 
   administrative domain. 
    


 
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   Lastly, as noted in [MLN-REQ], it is expected that solution documents 
   will include a full analysis of the security issues that any protocol 
   extensions introduce. 
    
 
6. Acknowledgments 
 
   We would like to thank Julien Meuric, Igor Bryskin and Adrian Farrel 
   for their useful comments. 
    
   Thanks also to Question 14 of Study Group 15 of the ITU-T for their 
   thoughtful review. 
    
 
7. References 
 
7.1. Normative 
    
   [RFC3979]    Bradner, S., "Intellectual Property Rights in IETF 
                Technology", BCP 79, RFC 3979, March 2005. 
 
   [RFC3945]    Mannie, E., et. al. "Generalized Multi-Protocol Label 
                Switching Architecture", RFC 3945, October 2004 
 
   [RFC4202]    Kompella, K., Ed. and Y. Rekhter, Ed., "Routing 
                Extensions in Support of Generalized Multi-Protocol 
                Label Switching", draft-ietf-ccamp-gmpls-routing, 
                RFC4202, October 2005. 
 
   [RFC3471]    Berger, L., et. al. "Generalized Multi-Protocol Label 
                Switching (GMPLS) Signaling Functional Description", RFC 
                3471, January 2003. 
                 
 
7.2. Informative 
    
   [RSVP-CALL]  Papadimitriou, D., Farrel, A., et. al., "Generalized 
                MPLS (GMPLS) RSVP-TE Signaling Extensions in support of 
                Calls", draft-ietf-ccamp-gmpls-rsvp-te-call, work in 
                progress. 
    
   [MLN-REQ]    Shiomoto, K., Papadimitriou, D., Le Roux, J.L., 
                Vigoureux, M., Brungard, D., "Requirements for GMPLS-
                based multi-region and multi-layer networks", draft-
                ietf-ccamp-gmpls-mrn-reqs, work in progess.  
    
   [RFC4206]    K. Kompella and Y. Rekhter, "LSP hierarchy with 
                generalized MPLS TE", draft-ietf-mpls-lsp-hierarchy, 
                RFC4206, October 2005. 
 


 
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   [GR-SHUT]    Ali, Z., Zamfir, A., "Graceful Shutdown in MPLS Traffic 
                Engineering Network", draft-ietf-ccamp-mpls-graceful-
                shutdown, work in progress.  
    
   [RFC4872]    Lang, Rekhter, Papadimitriou, "RSVP-TE Extensions in  
                 support of End-to-End Generalized Multi-Protocol Label 
                Switching (GMPLS)-based Recovery", RFC4872, May 2007. 
    
   [VNTM]       Oki, Le Roux, Farrel, "Definition of Virtual Network  
                 Topology Manager (VNTM) for PCE-based Inter-Layer MPLS 
                and GMPLS Traffic Engineering", draft-oki-pce-vntm-def, 
                work in progress. 
 
   [IW-MIG-FMWK]Shiomoto, K et al., "Framework for IP/MPLS-GMPLS  
                 interworking in support of IP/MPLS to GMPLS migration", 
                draft-ietf-ccamp-mpls-gmpls-interwork-fmwk, work in 
                progress.   
 
   [RFC3473]   Berger, L., et al. "GMPLS Singlaling RSVP-TE extensions",  
                RFC3473, January 2003. 
 
   [RFC4655]   Farrel, A., Vasseur, J.-P., Ash,J., "A PCE based 
                Architecture", RFC4655, August 2006. 
 
   [RFC4802]   Nadeau, T., Farrel, A., "GMPLS TE MIB", RFC4802, 
                February 2007. 
    
   [MPLS-SEC]   Fang, et al. "Security Framework for MPLS and GMPLS  
                Networks draft-fang-mpls-gmpls-security-framework, work  
                in progress. 
 
8. Editors' Addresses:  
  
   Jean-Louis Le Roux 
   France Telecom  
   2, avenue Pierre-Marzin  
   22307 Lannion Cedex, France 
   Email: jeanlouis.leroux@orange-ftgroup.com 
 
   Dimitri Papadimitriou 
   Alcatel-Lucent 
   Francis Wellensplein 1, 
   B-2018 Antwerpen, Belgium 
   Email: dimitri.papadimitriou@alcatel-lucent.be 
    
9. Contributors' Addresses:  
    
   Deborah Brungard 
   AT&T 
   Rm. D1-3C22 - 200 S. Laurel Ave. 
   Middletown, NJ, 07748 USA 
   E-mail: dbrungard@att.com 
 
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   Eiji Oki 
   NTT 
   3-9-11 Midori-Cho 
   Musashino, Tokyo 180-8585, Japan 
   Email: oki.eiji@lab.ntt.co.jp 
    
   Kohei Shiomoto 
   NTT 
   3-9-11 Midori-Cho 
   Musashino, Tokyo 180-8585, Japan 
   Email: shiomoto.kohei@lab.ntt.co.jp 
    
   M. Vigoureux 
   Alcatel-Lucent France 
   Route de Villejust 
   91620 Nozay 
   FRANCE 
   Email: martin.vigoureux@alcatel-lucent.fr 
 
 
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   This document and the information contained herein are provided 
   on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE 
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   IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL 
   WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY 
   WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE 
 
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   ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS 
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   Copyright (C) The IETF Trust (2007). This document is subject to the 
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