One document matched: draft-fedyk-gmpls-ethernet-pbt-00.txt



                                         
Network Working Group                     Don Fedyk, David Allan, Nortel 
Internet Draft                              Greg Sunderwood, Bell Canada 
Category: Standards Track                           Himanshu Shah, Ciena 
                                                                        
                                                                       
 
                                                               June 2006 
 
                         GMPLS control of Ethernet 
                   draft-fedyk-gmpls-ethernet-pbt-00.txt 
             (was: GMPLS Control of Ethernet IVL Switches)  
   
Status of this Memo 
    
   By submitting this Internet-Draft, each author represents that any 
   applicable patent or other IPR claims of which he or she is aware 
   have been or will be disclosed, and any of which he or she becomes 
   aware will be disclosed, in accordance with Section 6 of BCP 79. 
    
   Internet-Drafts are working documents of the Internet Engineering 
   Task Force (IETF), its areas, and its working groups.  Note that 
   other groups may also distribute working documents as Internet-
   Drafts. 
    
   Internet-Drafts are draft documents valid for a maximum of six months 
   and may be updated, replaced, or obsoleted by other documents at any 
   time.  It is inappropriate to use Internet-Drafts as reference 
   material or to cite them other than as "work in progress." 
    
   The list of current Internet-Drafts can be accessed at 
   http://www.ietf.org/ietf/1id-abstracts.txt. 
    
   The list of Internet-Draft Shadow Directories can be accessed at 
   http://www.ietf.org/shadow.html. 
    
   This Internet-Draft will expire in December 2006. 
 
Copyright Notice 
    
   Copyright (C) The Internet Society (2006). 
 
Abstract 
 
   This memo describes how GMPLS signaling may be applied to Provider 
   Backbone Transport (PBT) or configured Ethernet switches in order to 
   establish Ethernet P2P and P2MP MAC switched paths and P2MP VID based 
   trees. This utilizes a domain wide label for maintaining unique 
   Ethernet capabilities combined with GMPLS control.  
    

    
    
   Fedyk et.al          Expires December 2006                  Page 1 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
    
    
    
Table of Contents 
 
   1. Introduction...................................................4 
   2. Terminology....................................................4 
   3. Aspects of configuring Ethernet Forwarding.....................4 
   4. Overview of configuration of VID/MAC tuples....................7 
   5. Overview of configuration of VID port membership..............10 
   6. OAM Aspects...................................................10 
   7. QOS Aspects...................................................11 
   8. Resiliency Aspects............................................11 
   8.1  E2E Path protection.........................................11 
   8.2  Local Repair................................................11 
   9. Deployment Scenarios..........................................12 
   10.  Path creation and maintenance...............................12 
   10.1.1  Using a GMPLS Control Plane for Ethernet.................12 
   10.1.2  Control Plane Network....................................13 
   10.1.3  Signaling................................................13 
   10.1.4  Ethernet Label...........................................15 
   10.1.5  Ethernet Service.........................................16 
   10.1.6  GMPLS Routing............................................16 
   10.1.7  Path Computation.........................................17 
   10.1.8  Combinations of GMPLS Features...........................17 
   10.2  Addresses, Interfaces, and Labels..........................18 
   11.  Specific Procedures.........................................19 
   11.1  PT to PT connections.......................................19 
   11.2  P2P connections with shared forwarding.....................19 
   11.2.1  Dynamic P2P symmetry with shared forwarding..............20 
   11.2.2  Planned P2P symmetry.....................................20 
   11.2.3  Path Maintenance.........................................20 
   11.3  P2MP VID/MAC Connections...................................21 
   11.3.1  Setup procedures.........................................21 
   11.3.2  Maintenance Procedures...................................21 
   11.4  P2MP VID Trees.............................................21 
   11.4.1  Setup Procedures.........................................21 
   11.4.2  Maintenance procedures...................................22 
   11.5  OAM MEP ID and MA ID synchronization.......................22 
   11.6  Protection Paths...........................................23 
   12.  Error conditions............................................23 
   12.1  Invalid VID value for configured VID/MAC range.............23 
   12.2  Invalid VID value for configured VID range.................23 
   12.3  Invalid MAC Address........................................23 
   12.4  Invalid ERO for Upstream Label Object......................23 
   12.5  Invalid ERO for Suggested Label Object.....................23 
   12.6  Switch is not IVL capable..................................23 
   12.7  Switch is not SVL capable..................................23 
   12.8  Switch is not Asymmetric VID capable.......................23 
   12.9  Invalid VID in upstream label object.......................24 
   13.  Security Considerations.....................................24 
   14.  IANA Considerations.........................................24 
   15.  References..................................................24 
 
Fedyk et al.             Expires December 2006               Page 2 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   15.1  Normative References.......................................24 
   15.2  Informative References.....................................24 
   16.  Author's Address............................................25 
   17.  Intellectual Property Statement.............................26 
   18.  Disclaimer of Validity......................................26 
   19.  Copyright Statement.........................................27 
   20.  Acknowledgments.............................................27 














































 
Fedyk et al.             Expires December 2006               Page 3 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
 
 
1. Introduction 
    
   Ethernet switches are increasing in capability. As a consequence the 
   role of Ethernet is rapidly expanding in networks that were the 
   domain of other technologies such as SONET/SDH TDM and ATM. The 
   question of how Ethernet will evolve and what capabilities it can 
   offer in these areas is still under development.   
    
   This document explores some unique capabilities that Ethernet has and 
   blends them with some of the values of control planes developed in 
   the IETF.  
    
   Some of the techniques for repurposing Ethernet switching outlined 
   in this document have been introduced elsewhere as a complement to 
   IEEE 802.1ah Provider Backbone Bridging under the title "Provider 
   Backbone Transport"(PBT). PBT is simply the data plane of Ethernet 
   (802.1Q, 802.1ah) without a Spanning tree control plane. This 
   document applies to PBT and is applicable to 802.1 when used for a 
   suitable Pseudo wire service as described in this document.  
    
2. Terminology 
    
   In addition to well understood GMPLS terms, this memo uses 
   terminology from IEEE 802.1 and introduces a few new terms: 
    
   B-MAC        Backbone MAC 
   B-VID        Backbone VLAN ID 
   B-VLAN       Backbone VLAN 
   COS          Class of Service 
   C-MAC        Customer MAC 
   C-VID        Customer VLAN ID 
   C-VLAN       Customer VLAN 
   DMAC         Destination MAC Address 
   IVL          Independent VLAN Learning 
   MAC          Media Access Control 
   MP2MP        Multipoint to multipoint 
   PBB          Provider Backbone Bridge 
   PBT          Provider Backbone Transport 
   P2P          Point to Point 
   P2MP         Point to Multipoint 
   QOS          Quality of Service 
   SMAC         Source MAC Address 
   S-VID        Service VLAN ID 
   VID          VLAN ID 
   VLAN         Virtual LAN 
    
3. Aspects of configuring Ethernet Forwarding 
    
   Ethernet as specified today is a complete system consisting of a 
   data plane and a number of control plane functions. Spanning tree, 
   data plane flooding and MAC learning combine to populate forwarding 
 
Fedyk et al.             Expires December 2006               Page 4 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   tables and produce resilient any-to-any behavior in a bridged 
   network.  
    
   Ethernet consists of a very simple and reliable data plane that has 
   been optimized and mass produced. By simply disabling some Ethernet 
   control plane functionality, it is possible to employ alternative 
   control planes and obtain different forwarding behaviors. 
    
   Customer     Provider        Provider         
   Bridge/      Bridge          Backbone                                         
                                Bridge 
        
   C-MAC/C-VID------------------802.1Q -------------------C-MAC-CVID 
                S-VID-----------802.1ad------------S-VID 
                        B-MAC---802.1ah---B-MAC 
                        B-VID---802.1ah---B-VID 
    
                     Figure 1 802.1 MAC/VLAN Hierarchy 
    
   Recent works in IETF Pseudo Wire Emulation [PWE] and IEEE 802 are 
   defining a separation of Ethernet functions permitting an increasing 
   degree of provider control. The result is that the Ethernet service 
   to the customer appears the same, yet the provider components and 
   behaviors have become decoupled from the customer presentation and 
   the provider has gained control of all MAC endpoints. 
     
   One example of this is the 802.1ah work in hierarchical bridging 
   whereby customer Ethernet frames are fully encapsulated into a 
   provider Ethernet frame, isolating the customer MAC space from the 
   provider MAC space. Another example would be the direct transport of 
   pseudo wires PWs ["Dry Martini" or PW over layer 2] where the 
   Ethernet network fulfills the role of the PSN in the PWE 
   architecture. In both cases the behavior of the provider's network 
   is as per 802.1Q. 
    
   The Ethernet data plane provides protocol multiplexing via the ether 
   type field which allows encapsulation of different protocols 
   supporting various applications. More recently, the Carrier Ethernet 
   effort has created provider and customer separation that enables 
   another level of multiplexing. This in effect creates provider MAC 
   endpoints in the Ethernet sub-network controlled by the provider. In 
   this document we concentrate on the provider solutions and therefore 
   subsequent references to VLAN, VID and MAC refer to those under 
   provider control, be it in the backbone layer of 802.1ah or the PSN 
   layer of "Dry Martini". Also in the case where the Customer service 
   is Ethernet, the Customer Ethernet service is the same native 
   Ethernet service with functions such as bridging, learning and 
   spanning trees all functioning over the provider infrastructure. 
    
   With the provider in exclusive control of their Ethernet sub-network 
   and all customer specific state pushed to the edges of that sub-
   network, the ability of the provider to exploit latent Ethernet 
   behavior is facilitated. One key capability sought is to overcome 
 
Fedyk et al.             Expires December 2006               Page 5 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   limitations, such as single spanning tree path for all traffic 
   within a VLAN, imposed by bridging (see [MYERS] for a discussion). 
    
   Bridging offers a simple solution for any-to-any connectivity within 
   a VLAN partition via the Spanning tree. Spanning tree provides 
   unnecessary capability for point to point services and since the 
   Spanning tree must interconnect all MACs with the same VLAN IDs it 
   consumes a scarce resource (VIDS). It is easier to modify Ethernet 
   to scale engineered P2P services and this is the approach we take 
   with PBT and PW over Ethernet. (The number of usable VLANs IDs in 
   conventional Ethernet bridging is constrained to 4094, therefore the 
   use of VLAN only configuration for all forwarding could be limited 
   for some applications where large number of point to point 
   connections are required.) This is because in Ethernet, each 
   Spanning trees is associated with one or more VLAN IDs. Also Port 
   membership in a VLAN is configured which controls the connectivity 
   of all MAC interfaces participating in the VLAN.  
    
   The roots for PBT capability exist in the Ethernet management plane. 
   The management of Ethernet switches provides for static 
   configuration of Ethernet forwarding. The Ethernet Control plane 
   allows for forwarding entries that are statically provisioned or 
   configured. In this document we are expanding the meaning of 
   "configured" from an Ethernet Control plane sense to mean either 
   provisioned or controlled by GMPLS. The connectivity aspects of 
   Ethernet forwarding is based upon VLANs and MAC addresses. In other 
   words the VLAN + DMAC are an Ethernet Label that can be looked up at 
   each switch to determine the egress link (or links in the case of 
   link aggregation).  
                      
   In this document, we discuss, point to point (P2P) and point to 
   multipoint (P2MP) connections via static configuration of VLAN/MAC 
   tuples. (MAC-only configuration is considered a degenerate case 
   corresponding to VLAN zero). 
    
   This is a finer granularity than traditional VLAN networks since 
   each P2P connection is independent. By provisioning MAC addresses 
   independent of Spanning tree in a domain, both the VLAN and the 
   VLAN/MAC configured forwarding can be exploited. This greatly 
   extends the scalability of what can be achieved in a pure Ethernet 
   bridged sub network. 
    
   For compatibility and flexibility with existing Ethernet hardware, 
   we preserve the global/domain wide uniqueness and semantics of MAC 
   addresses as interface names or multicast group addresses. We then 
   redefine the semantics associated with administration and uses of 
   VLAN values for the case of explicit forwarding such as you get with 
   IVL. 
    
   The result is a new architecture where configured VID + DMAC provide 
   a forwarding table that is consistent with existing Ethernet 
   switching. At the same time it provides domain wide labels that can 
   be controlled by a common GMPLS control plane. This makes GMPLS 
 
Fedyk et al.             Expires December 2006               Page 6 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   control and resource management procedures ideal to create paths. 
   The outcome is that the GMPLS control plane can be utilized to set 
   up the following atomic modes of connectivity: 
    
    
    
          1) P2P connectivity and MP2P multiplexed connectivity based 
             on configuration of unicast MAC addresses in conjunction 
             with a VID from a set of pre-configured VIDs. 
          2) P2MP connectivity based on configuration of multicast MAC 
             address in conjunction with a VID from a set of pre-
             configured VIDs. This corresponds to (Source, Group) or 
             (S,G) multicast. 
          3) P2MP connectivity based on configuration of VID port 
             membership. This corresponds to (S,*) or (*,*) multicast 
             (where * represents the extent of the VLAN Tree). 
          4) MP2MP connectivity based on configuration of VID port 
             membership (P2MP trees in which leaves are permitted to 
             communicate). Although, we caution that this approach 
             poses resilience issues (discussed in section 5) and hence 
             is not recommended. 
    
   Items 1 and 2 above are restricted to "Independent VLAN Learning" 
   capable Ethernet switches [802.1Q].  
    
   The modes above are not completely distinct. Some modes involve 
   combinations of P2P connections in one direction and MP connectivity 
   in the other direction.  Also, more than one mode may be combined in 
   a single GMPLS transaction. One example is the incremental addition 
   of a leaf to a P2MP tree with a corresponding MP2P return path 
   (analogous to a root initiated join).  
    
   In order to realize the above connectivity modes, a partition of the  
   VLAN IDs from traditional Ethernet needs to be established. The 
   partition allows for a pool of Ethernet labels for manual 
   configuration and/or for GMPLS control plane usage. The VID 
   partition actually consists of a "configured VID/MAC range" and 
   "configured VID range" since in some instances the label is a 
   VID/DMAC and sometimes the label is a VID/Mulitcast DMAC.  
    
4. Overview of configuration of VID/MAC tuples 
    
   Existing Ethernet Switches may perform Independent VLAN Learning 
   (IVL) based forwarding on the basis of a VID/DMAC tuple as described 
   in 802.1Q. This means the forwarding hardware performs a full 60 bit 
   lookup (VID (12) + DMAC(48)), only requiring uniqueness of the full 
   60 bits for forwarding to resolve correctly. We can call this an 
   Ethernet domain wide label.  
    
   The label becomes unique MAC address in the domain per VLAN. We have 
   complete route freedom for each label (60 bit VLAN/MAC tuple) and 
   the ability to define multiple connectivity instances or paths per 
   MAC for each of the VIDs in the "configured VID/MAC range".  
 
Fedyk et al.             Expires December 2006               Page 7 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
    
   We have preserved the semantics of MAC addresses, and simply broaden 
   the potential interpretations of VLAN ID from spanning tree 
   identifier to topology instance identifier. Therefore, we can 
   concurrently operate both standard bridging and configured 
   unicast/multicast operation side by side. We partition the VID space 
   and allocate a range of VIDs (say 'n' VIDs) as only significant when 
   combined with a configured MAC address (the aforementioned 
   "configured VID/MAC range" of VIDs). We can then consider a VID in 
   that range as an individual connectivity instance identifier for a 
   configured P2P path terminating at the associated destination MAC 
   address. Or in the case of P2MP, a P2MP multicast tree corresponding 
   to the destination multicast group address. Note that this is 
   destination based forwarding consistent with how Ethernet works 
   today. The only thing changed is the mechanism of populating the 
   forwarding tables.  
    
   Ethernet MAC addresses are typically globally unique since the 48 
   bits consists of 24 bit Organizational Unique Identifier and a 24 
   bit serial number. There is also a bit set aside for Multicast and 
   for local addresses out OUI field. We define domain wide as within a 
   single organization, or more strictly within a single network within 
   an organization. For provider MAC addresses that will only be used 
   in a domain wide sense we can define MAC addresses out of a either 
   the local space or the global space since they both have the domain 
   wide unique property. When used in the context of GMPLS is useful to 
   think of a domain wide pool of labels where switches are assigned a 
   set of MAC addresses. These labels are assigned traffic that 
   terminates on the respective switches.  
    
   It is also worth noting that unique identification of source in the 
   form of the SMAC is carried e2e in the MAC header. So although we 
   have a 60 bit domain wide unique label, it may be shared by multiple 
   sources and the full connection identifier for an individual P2P 
   instance is 108 bits (SMAC, VID and DMAC). The SMAC is not 
   referenced in forwarding operations but it would allow additional 
   context for tracing or other operations at the end of the path.   
    
   GMPLS signaling procedures can be designed to create the bi-
   directional path delegating label allocation of the combined MAC/VID 
   Label to the destination/source associated with the MACs for each 
   direction of unicast forwarding. Creating P2P path is a well 
   understood control plane requirement. 
    
   For multicast group addresses, the VID/MAC concatenated label can be 
   distributed by the source but label assignment (as it encodes global 
   multicast group information) requires coordination within the GMPLS 
   controlled domain. 
    
   As mentioned earlier, this technique results in a single unique and 
   invariant identifier, in our case a VID/MAC label associated with 
   the path termination or the multicast group.  There can be up to 
   4094 labels to any one MAC address.  This is a large number for P2P 
 
Fedyk et al.             Expires December 2006               Page 8 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   applications and extremely large when shared or multiplexed 
   forwarding is leveraged. In practice, most network scaling 
   requirements may be met via allocation of only a small portion of 
   the VID space, to the configured VID/MAC range. The result is 
   minimal impact on the number of remaining bridging VLANs that can be 
   concurrently supported.  
    
   In order to use this unique 60 bit label, we disable the normal 
   mechanisms by which Ethernet populates the forwarding table for the 
   allocated range of VIDs. We use GMPLS signaling to create paths and 
   assign labels to the forwarding table. When a path is setup, for a 
   specific label across a contiguous sequence of Ethernet switches, a 
   unidirectional connection is the functional building block for an 
   Ethernet Label Switched path (Eth-LSP).  
    
   In P2P mode a bi-directional path is composed of two unidirectional 
   paths that are created with a single RSVP-TE session. The technique 
   does not require the VID to be common in both directions. However, 
   keeping in line with regular Ethernet these paths are symmetrical 
   such that a single bi-directional connection is composed of two 
   unidirectional paths that have common routing (i.e. traverse the 
   same switches and links) in the network and hence share the same 
   fate. One departure from current GMPLS signaling is there needs to 
   be a provision for asymmetrical bandwidth reservations.  
    
   In P2MP mode a bi-directional path is composed of a unidirectional 
   tree and a number of P2P paths from the leaves of the tree to the 
   root. Similarly these paths may have bandwidth and must have common 
   routing as in the P2P case.  
    
   There are a few modifications required to standard Ethernet to make 
   this approach robust: 
    
   1. In Standard Ethernet, discontinuities in forwarding table 
   configuration in the path of a connection will normally result in 
   packets being flooded as "unknown". For configured operation (e.g. 
   PBT), unknown addresses are indicative of a fault or configuration 
   error and the flooding of these is undesirable in meshed topologies. 
   Therefore flooding of "unknown" unicast/multicast MAC addresses must 
   be disabled for the "configured VID/MAC range".  
    
   2. MAC learning is not required, and although it will not interfere 
   with management/control population of the forwarding tables, since 
   static entries are not overridden, it appears prudent to explicitly 
   disable MAC learning for the configured VID/MAC and VID range. 
    
   3. Spanning tree is disabled for the allocated VID/MAC and VID range 
   and port blocking must be disabled to achieve complete configured 
   route freedom. As noted earlier, it is a control plane requirement 
   to ensure configured paths are loop free.  
    


 
Fedyk et al.             Expires December 2006               Page 9 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   All three modifications described above are within the scope of 
   acceptable configuration options defined in IEEE802.1Q 
   specification. 
    
    
5. Overview of configuration of VID port membership 
    
   Procedures almost identical to that for configuration of P2P VID/MAC 
   tuples can also be used for the incremental configuration of P2MP 
   VID trees. For the replication of forwarding in this case the label 
   is common for the multipoint destinations. The MAC field is set to 
   multicast address and is common to the multicast community. The VID 
   is a distinguisher common to the multicast community. The signaling 
   procedures are as per that for [MPLS-P2MP]. 
    
   Since VID translation is relatively new and is not a ubiquitously 
   deployed capability, we consider a VID to be a domain global value. 
   Therefore, the VID value to be used by the originating switch may be 
   assigned by management and nominally is required to be invariant 
   across the network. The ability to indicate permissibility of 
   translation will be addressed in a future version of the document. 
    
   A procedure known as "asymmetrical VID" may be employed to constrain 
   connectivity (root to leaves, and leaves to root only) when switches 
   also support shared VLAN learning (or SVL). This would be consistent 
   with the root as a point of failure.  
    
6. OAM Aspects 
    
   Robustness is enhanced with the addition of data plane OAM to 
   provide both fault and performance management.  
    
   For the configured VID/MAC unicast mode of behavior, the hardware 
   performs unicast packet forwarding of known MAC addresses exactly as 
   Ethernet currently operates The OAM currently defined,[802.1ag, 
   Y.1731] can also be reused without modification of the protocols.  
    
   An additional benefit of domain wide path identifiers for data plane 
   forwarding, is the tight coupling of the 60 bit unique connection ID 
   (VID + DMAC ) and the associated OAM packets. It is a simple matter 
   to determine a broken path or misdirected packet since the unique 
   connection ID cannot be altered on the Eth-LSP. This is in fact one 
   of the most powerful and unique aspects of the domain wide label for 
   any type of rapid diagnosis of the data plane faults. It is also 
   independent of the control plane so it works equally well for 
   provisioned or GMPLS controlled paths.  
    
   Bi-directional transactions (e.g. ETH-LB) and reverse direction 
   transactions (e.g. ETH-AIS) will have a different VID for each 
   direction. Currently Y.1731 & 802.1ag makes no representations with 
   respect to this. 
    

 
Fedyk et al.             Expires December 2006               Page 10 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   For configured multicast VID/MAC mode, the current versions of 
   802.1ag, Y.1731] make no representation as to how PDUs which are not 
   using unicast addresses or which use OAM reserved multicast 
   addresses are handled. Therefore this specification makes no 
   representation as to whether such trees can be instrumented. 
    
   For configured VID mode of operation, the OAM functions as defined 
   in the current versions of 802.1ag, Y.1731 can be used with no 
   restriction. 
    
7. QOS Aspects 
    
   Ethernet VLAN tags include priority tagging in the form of the 
   802.1p priority bits. When combined with configuration of the paths 
   via management or control plane, priority tagging produces the 
   Ethernet equivalent of an MPLS TE E-LSPs [MPLS-DS]. Priority tagged 
   Ethernet PDUs self-identify the required queuing discipline 
   independent of the configured connectivity.  
    
   It should be noted that the consequence of this is that there is a 
   common COS model across the different modes of configured operation 
   specified in this document. 
    
   The actual QOS objects required for signaling will be in a future 
   version of this memo. 
    
8. Resiliency Aspects 
    
8.1  E2E Path protection 
    
   1:1 and 1+1 path protection strategies are supported. Such schemes 
   offer: 
          1) Engineered disjoint protection paths that can protect both 
             directions of traffic. 
          2) Fast switchover due to tunable OAM mechanisms.  
          3) Revertive path capability when primary paths are restored. 
          4) Option for redialing paths under failure.  
    
   Specific procedures for establishment of protection paths and 
   associating paths into "protection groups" are described later in 
   this document. 
    
   Note that E2E path protection is able to respond to failures with a 
   number of configurable intervals. The loss of CCM OAM cells or ETH-
   AIS cells in the data plane can trigger paths to switch. In the case 
   of CCM OAM cells the detection time is a typically 3.5 the CCM 
   interval + the propagation delay from the fault.   
    
8.2  Local Repair  
    
   At this time local repair such as IPFRR with detours or bypass 
   tunnels is not considered as there are obstacles both with Ethernet 
   and the labeling techniques described in this document. Alternate 
 
Fedyk et al.             Expires December 2006               Page 11 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   path techniques such as warm standby and hot standby work well since 
   data path OAM is able to provide configurable response time as 
   mentioned earlier.  
    
     
    
9. Deployment Scenarios  
    
   This technique of GMPLS controlled Ethernet switching is applicable 
   to all deployment scenarios considered by the design team [CCAMP-
   ETHERNET]. 
    
10. Path creation and maintenance 
    
   One simple mode of path creation described earlier is configuration. 
   Switch by switch a path can be created by simple configuration and 
   assignment of labels or by a set of commands originating from a 
   management system. When configuring a PBT path the label VID + DMAC 
   is assigned hop by hop invariant and it is intuitive to associate 
   the label with the path. While this property is a desirable 
   attribute, to be consistent with GMPLS terminology, and more 
   accurate, paths are created first as an ERO and labels are assigned 
   from the available label pool. In this case we use a domain wide 
   label.   
    
   One improvement to switch by switch configuration is to move to 
   single ended provisioning and signaling. Since signaling of explicit 
   paths is the domain of CCAMP and GMPLS we discuss the applicability 
   of GMPLS to this problem.   
    
   Several attributes may be associated with an Eth-LSP, including: 
   - bandwidth requirements of the path. This can be used, for example, 
   to request a fixed bandwidth path, where the committed information 
   rate and peak information rate of the path are equivalent. 
   - priority level; 
   - preemption characteristics; 
   - protection/resiliency requirements; 
   - routing policy, such as an explicit route; 
   - policing requirements 
    
   In addition to the above policies based on either under-subscription 
   or over-subscription can be supported.  
    
    
10.1.1  Using a GMPLS Control Plane for Ethernet 
    
   GMPLS [GMPLS-ARCH] has been adapted to the control of optical 
   switches for the purpose of managing optical paths. GMPLS signaling 
   is well suited to setup paths with labels but it does require a 
   minimal IP control plane and IP connectivity, so it is suited to 
   certain scenarios where a large number of paths or dynamic path 
   management is required.    
    
 
Fedyk et al.             Expires December 2006               Page 12 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   In many Ethernet deployment situations the addition of a complete 
   GMPLS control plane may be excessive for the switches or the 
   application.  For discussion purposes we decompose the problem into 
   Signaling, Routing, Link discovery and Path management. While we 
   discuss the options it will become apparent that using all functions 
   of GMPLS is less of an operational overhead than any other 
   combination. Also, using only some components of GMPLS can lead to 
   more provisioned parameters than a purely static system (see 
   "Combinations of GMPLS Features").   
    
   Link discovery is one of the foundations of GMPLS. It is also a 
   capability that has been specified for Ethernet in IEEE 802.1AB. All 
   link discovery is optional but the benefits of running link 
   discovery in large systems are significant. It reduces configuration 
   and the possibility of errors in configuration. A recommendation is 
   that 802.1AB could be run with an extension to feed information into 
   an LMP [LMP] information model. See Figure 3.    
    
               +---------+           +---------+ 
               |         |           |         |    
               |  LMP    | ----------|  LMP    | 
               | +-------+  IP (opt) +-------+ | 
               | |802.1AB| ----------|802.1AB| |  
               +-+-------+  Ethernet +-------+-+ 
                                      
                     Figure 3 Link Discovery Hierarchy 
                                       
10.1.2  Control Plane Network 
 
   In order to have a GMPLS control plane, an IP control plane 
   consisting of an IGP with TE extension needs to be established. This 
   IGP sees each hop as a terminated IP adjacency and should not be 
   interpreted as a distinct routed subnet for the purpose of carrying 
   IP bearer traffic. 
    
   This IP control plane can be provided as a separate independent 
   network (out of band) or integrated with the Ethernet switches.  
    
   If the IP control plane is a separate network, it may be provided as 
   a Layer 2 connected VLAN where the Ethernet switches are connected 
   via a bridged network or HUB.  It may also be provided by an 
   external network that provides IP connectivity but the 
   GMPLS/Ethernet switches are not immediately adjacent to each other.  
    
   If the IP control plane is integrated with the switches it may be 
   provided by a bridged VLAN that uses the Data bearing channels of 
   the network between adjacent nodes. This ties the fate of the 
   controlled paths and the IP control plane links, but it is likely 
   the same Ethernet hardware is already using shared network resources 
   with other networks.   
                            
10.1.3  Signaling  
    
 
Fedyk et al.             Expires December 2006               Page 13 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   GMPLS signaling is well suited to the set up of PBT on Ethernet 
   switches. GMPLS signaling uses either numbered or unnumbered links 
   where the link is either explicitly IP addressed or associated with 
   a switch loopback address. If LMP [LMP] is used, the creation of 
   these unnumbered interfaces can be automated. If LMP is not used 
   there is an additional provisioning requirement to add GMPLS link 
   identifiers. For large-scale implementations LMP would be 
   beneficial. As mentioned earlier the primary benefit of signaling is 
   the control of a path from an endpoint. GMPLS can be used to create 
   bi-directional or unidirectional paths, bi-directional paths being 
   the preferred mode of operation for numerous reasons (OAM 
   consistency etc.). In this document we only consider bidirectional 
   paths both for P2P and P2MP services.    
    
   Signaling enables the ability to dynamically establish a path and to 
   adjust the path in a coordinated fashion after the path has been 
   established. Signaling also allows multi-vendor interoperability 
   since the signaling is based on GMPLS signaling protocols. This 
   allows the network to adapt to changing conditions or failures with 
   a single mechanism. Signaling can be used for pure static paths as 
   well.    
    
   To use GMPLS RSVP-TE for signaling, a new label is defined that 
   contains the VID/DMAC tuple, which is 60 bits.  On the initiating 
   and terminating nodes, a function administers the VIDs associated 
   with the MAC SMAC and DMAC respectively.   
    
   To initiate a bi-directional VID/MAC P2P or P2MP path, the initiator 
   of the PATH message uses procedures outlined in [GMPLS-SIGNALING] 
   possibly augmented with [MPLS-P2MP], it: 
    
   1) Sets the LSP encoding type to Ethernet. 
         
   2) Sets the LSP switching type to MAC [IANA to define]. 
         
   3) Sets the GPID to Unknown (1) or Ethernet Multiplexed [IANA to 
   define]. 
         
   4) Sets the UPSTREAM_LABEL to the VID/SMAC tuple where the VID is 
   administered from the configured VID/MAC range. Downstream switches 
   must use the suggested label or return a path Error condition 
   indicating why the label could not be used.  
    
   At intermediate switches the UPSTREAM_LABEL object and value is 
   passed unmodified.  The VID/SMAC tuple is installed in the 
   forwarding table at each hop for the upstream direction.  
    
   Note that shared forwarding happens opportunistically when 
   conditions are met as a local decision. To achieve shared 
   forwarding, a Path computation engine must ensure the ERO is 
   consistent with an existing path for the shared segments. The only 
   other criterion is the paths cannot separate and cross.  If no 
   existing path has this behavior the path will be created unshared.  
 
Fedyk et al.             Expires December 2006               Page 14 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   In other words shared forward happens when paths share segments from 
   the source and when the Upstream label is chosen to be the same as 
   the existing path.  Similarly for the downstream path shared 
   forwarding happens when, an existing path that shares segments with 
   the new paths ERO, viewed from the destination switch and when the 
   downstream label is chosen to be the same and the existing path.  
   In this manner shared forwarding is a function that is controlled 
   primarily by path calculation and in combination with the local 
   label allocation at the end points of the path.  
    
   At the destination, a VID is allocated in the local MAC range for 
   the DMAC and the VID/DMAC tuple is passed in the GENERALIZED_LABEL 
   in the RESV message.  As with the UPSTREAM_LABEL, intermediate 
   switches use the GENERALIZED_LABEL object and pass it on unchanged, 
   upstream.  The VID/DMAC tuple is installed in the forwarding table 
   at each hop. This creates a bi-directional path as the PATH and RESV 
   messages follow the same path. 
    
   To initiate a P2MP VID path the initiator of the PATH message uses 
   procedures outlined in [GMPLS-SIGNALING] and [MPLS-P2MP]. A P2MP 
   tree consists of a VID tree in the forward direction (from root to 
   leaves) and a set of P2P paths running on identical paths from Tree 
   to root in the reverse direction. VID labels with common MAC 
   addresses are allocated in the forward direction and a single 
   VID/MAC label in the reverse direction: 
    
   1) Sets the LSP encoding type to Ethernet. 
         
   2) Sets the LSP switching type to L2SC. 
         
   3) Sets the GPID to unknown. 
    
   4) Set the technology specific information in the TSPEC to indicate 
   domain-wide label.  
    
   5) Sets the UPSTREAM LABEL specified as a single VID/MAC from the 
   configured VID range. 
    
   6) VID translation may optionally be permitted on a local basis 
   between two switches by a downstream switch replying with a VID/MAC 
   other than the SUGGESTED LABEL. The upstream switch then sets a VID 
   translation on the port associated with the label to allow VID 
   translation. This flexibility allows the tree to be constructed with 
   out having to worry about colliding with another tree using the same 
   VID. 
     
    
10.1.4  Ethernet Label 
    
   The Ethernet label is a new generalized label with a suggested 
   format of: 
    
    
 
Fedyk et al.             Expires December 2006               Page 15 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
    
    
       0                   1                   2                   3 
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |0 0 0 0|        VLAN ID        |       MAC (highest 2 bytes)   | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
      |                       MAC Address                             | 
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
    
    
   Note that there is no syntax in signaling to force the label in the 
   UPSTREAM_LABEL and GENERALIZED_LABEL objects to be passed unchanged 
   (which needs to be addressed). 
    
   The semantics of the new label type for a non-zero MAC address is 
   that that the label is passed unchanged. This label is a domain wide 
   label.  This has similarity to the way in which a wavelength label 
   is handled at an intermediate switch that cannot perform wavelength 
   conversion, and is described in [GMPLS-RSVP]. 
    
   These domain wide labels are allocated to switches that control the 
   assignment of labels. This label space does not have to be globally 
   unique because the labels are only valid within a single provider.  
   When using configuration, a tool would have to perform a consistency 
   check to make sure that label terminations were unique. When using 
   GMPLS signaling it is assumed a unique pool of labels would be 
   assigned to each switch. The DMAC addresses are domain wide unique 
   and so is the combination of VID/DMAC. Should an error occur and a 
   duplicate label be assigned to one or more switches GMPLS signaling 
   procedures would allow the first assignment of the label and prevent 
   duplicate label from colliding. If a collision occurs an alarm would 
   be generated. In fact some of these procedures have been defined in 
   GMPLS control of photonic networks where a lambda may exist as a 
   form of domain wide label. 
    
 
10.1.5  Ethernet Service 
    
   Ethernet Switched Paths that are setup either by configuration or 
   signaling can be used to provide an Ethernet service to customers of 
   the Ethernet network.  The Metro Ethernet Forum has defined some 
   services in MEF.6 (e.g., Ethernet Private Line), and these are also 
   aligned with ITU-T G.8011-x Recommendations.  Of particular interest 
   are the bandwidth profile parameters in MEF.10 and whose associated 
   bandwidth profile algorithm are based on [DS-COLOR][MPLS-DS].  
   Consideration should be given to supporting these in any signaling 
   extensions for Ethernet LSPs. This will be addressed in a future 
   version of this specification. 
 
10.1.6  GMPLS Routing 
    

 
Fedyk et al.             Expires December 2006               Page 16 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   GMPLS routing [GMPLS-ROUTING] is IP routing with the TLV extensions 
   for the purpose of carrying around GMPLS TE information. The TE 
   information is populated with TE resources from LMP or from 
   configuration if LMP is not available. GMPLS Routing is an optional 
   piece but it is highly valuable in maintaining topology for path 
   management and dynamic path computation.  
    
10.1.7  Path Computation 
    
   There has been a lot of recent activity in the area of path 
   computation [PATH-COMP].  Originally MPLS path computation was 
   performed locally in a TE database on a router. While this is non-
   optimal for situations where bandwidth is highly managed, it was 
   acceptable when a few paths are required in a primarily 
   connectionless environment; if a large number of coordinated paths 
   are required, it is advantageous to have a more sophisticated path 
   computation engine capable of optimizing the path routing of a sub 
   network. The path computation could take the form of paths being 
   computed either on a management station with local computation for 
   rerouting or more sophisticated Path computation servers.  
    
   Path computation in GMPLS generates explicit route objects (EROs) 
   that can be used directly by GMPLS signaling. The implication is 
   that the TE database and path computation engine may not be co-
   located with the Ethernet LSR.  
    
10.1.8  Combinations of GMPLS Features 
    
   The combinations of LMP, Routing, Signaling and Path computation can 
   be all supported on a switch or a subset of GMPLS features can be 
   supported.  
    
   Signaling is the minimal function that might be supported on a small 
   switch. The ability to process Signaling messages with an ERO may be 
   all that is desired on an end point. In this case the path 
   computation would be performed off network.  
    
   Routing for GMPLS is the next important function since it provides 
   the forwarding of signaling functions and transport of TE 
   information. There is no requirement to provide full IP routing for 
   data traffic, only hop by hop routing for the control plane. However 
   it is possible to design switches without routing that could proxy 
   their routing to other larger switches. In the proxied case, there 
   would be little difference in the routing database but the small 
   switches would not have to perform routing operations. The 
   information for the proxied routing might be configured or it might 
   be data filled by an automated procedure.  No new protocols are 
   envisioned for the case where routing is proxied.  
    
   LMP is optional as mentioned earlier. The primary benefit of LMP in 
   addition to 802.1AB is LMP's capability to optimize routing 
   information for the purpose of link bundling on large switches. LMP 
   has the capability to compress the information required to represent 
 
Fedyk et al.             Expires December 2006               Page 17 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   a large number of parallel resources automatically and reduce the 
   amount of configuration.  
    
    
10.2 Addresses, Interfaces, and Labels 
    
   This specification uses an addressing scheme and a label space for 
   the ingress/egress connection; the hierarchical GMPLS Switch 
   Address/Port ID and the Ethernet VID/DMAC tuple or VID/Multicast MAC 
   as a label space.  
    
                                     GMPLS Switch Address 
                                             | 
                                             V          N=named port 
        +----+                            +-----+         <port index> 
        |    |       label=VLAN/MAC       |     |         <MAC> 
        | PB |       label=VID/MMAC       |     |         <string> 
   -----N    N----------------------------N PBB N---------- 
        |    |                            |(MAC)|   \     
        |    |                            /     |     Externally 
        +----+                           /+-----+     Facing      
      PBT Transit    Provider Egress MAC/ PBT edge    Ports 
        Switch          (Label)            Switch 
    
             Figure 4 Ethernet/GMPLS Addressing & Label Space 
    
    
   Depending on how the service is defined and set up one or more of 
   these identifiers may be used for actual setup. Also note that 
   although it is possible for a terminating switch to offer any 60 bit 
   label value that can be guaranteed to be domain wide unique, the 
   convention of using MAC addresses to name specific ports is retained. 
   An Ethernet port name is common to both configured MAC/VID, 
   configured VID and bridging modes of operation. One implication of 
   this is that a port index and a MAC address of a port on the switch 
   may be effectively interchangeable for signaling purposes. 
    
   For a GMPLS based system, the GMPLS Switch Address/logical port is 
   the logical signaling identifier for the control plane via which 
   Ethernet layer label bindings are solicited. In order to create a 
   point to point path an association must be made between the ingress 
   and egress node.  But the actual label distributed via signaling and 
   instantiated in the switch forwarding tables identifies the egress 
   MAC of the PBT tunnel (see Figure 4). This label may be the same as 
   the externally facing port if global labels are used or it may be an 
   internal provider hidden domain wide label.  
    
   GMPLS uses identifiers in the form of 32 bit numbers which are in the 
   IP address notation but these are not IP addresses. An IP routing 
   control plane for the propagation of TE information may be supported.  
   The provider MAC addresses are exchanged by the LLDP and by LMP if 
   supported. Actual label assignment is performed by the signaling 
   initiator and terminator. 
 
Fedyk et al.             Expires December 2006               Page 18 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
                                                         
   A particular port on a provider network switch would have:  
   - A MAC 
   - A 32 bit IPv4 Switch address or 128 bit IPv6 address plus 32 bit 
     port Identifier  
   - One (or more) Mnemonic String Identifiers 
    
   This multiple naming convention leaves the issue of resolving the set 
   given one of the port identifiers. On a particular node, mapping is 
   relatively straight forward.  The preferred solution to this is to 
   use the GMPLS IP switch address for signaling resolution. In so 
   doing, the problem of setting up a path is reduced to figuring out 
   what switch supports a egress MAC address and then finding the 
   corresponding GMPLS IP switch address and performing all signaling 
   and routing with respect to the GMPLS switch address.  
    
   There are several options to achieve this:  
   - Provisioning 
   - Auto discovery protocols that carry MAC address 
   - Augmenting Routing TE with MAC Addresses 
   - Name Servers with identifier/address registration 
    
   This will be clarified in a subsequent version of this document. 
    
    
11. Specific Procedures 
    
11.1 PT to PT connections  
    
   The Data Plane for IVL has three key fields: VID, DMAC and SMAC.  A 
   connection instance is uniquely identified by the DMAC, the VID and 
   the SMAC for the purpose of the provider network terminations. The 
   VID and DMAC tuple identifies the forwarding multiplex at transit 
   switches and a simple degenerate form of the multiplex is P2P (only 
   one SMAC/VID/DMAC connection uses the VID/DMAC tuple).  
    
   This results in unique labels end to end and no merging or 
   multiplexing of tunnels. The data streams may merge but the 
   forwarding entries are unique allowing the connection to be de-
   multiplexed downstream.     
    
11.2    P2P connections with shared forwarding 
    
   The VID/DMAC can be considered to be a shared forwarding identifier 
   or label for a multiplex consisting of some number of P2P connections 
   distinctly identified by the MAC SMAC/VID/DMAC tuple. The reason for 
   using a shared forwarding entry is it reuses existing labels.  
    
   VLAN tagged Ethernet packets include priority marking. Priority bits 
   can be used to indicate class of Service (COS) and drop priority. 
   Thus, traffic from multiple COSs could be multiplexed on the same ESP 
   (i.e., similar to E-LSPs) and queuing and drop decisions are made 
   based on the p-bits. This means that the queue selection can be done 
 
Fedyk et al.             Expires December 2006               Page 19 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   based on a per flow (i.e., ESP + priority) basis and is decoupled 
   from the actual steering of the packet at any given node.  
    
   A terminating switch will frequently have more than one suitable 
   candidate path may choose to share a forwarding entry.(common 
   VID/DMAC , unique SMAC). It is a local decision of how this is 
   performed but the best choice is a path that maximizes the shared 
   forwarding.  
    
   The concept of bandwidth management still applies with equally well 
   with shared forwarding. As an example consider a PBT edge switch that 
   terminates an Ethernet LSP with the following attributes: bandwidth 
   B1, DMAC D, SMAC S1, VID V. A request to establish an additional 
   Ethernet LSP with attributes (bandwidth B2, DMAC D, SMAC S2, VID V) 
   can be accepted provided there is sufficient link capacity remaining. 
    
    
11.2.1 Dynamic P2P symmetry with shared forwarding 
    
   Similar to how a destination switch may select a VID/DMAC from the 
   set of existing shared forwarding multiplexes rooted at the 
   destination node, the originating switch may also do so for the 
   reverse path. Once the initial ERO has been computed and the set of 
   existing Ethernet LSPs that include the target DMAC have been pruned, 
   the originating switch may select the optimal (by whatever criteria) 
   existing shared forwarding multiplex for the new destination to merge 
   with and offer its own VID/DMAC tuple for itself as a destination. 
   This is identified via use of the UPSTREAM LABEL object. 
    
11.2.2  Planned P2P symmetry 
    
   Normally the originating switch will not have knowledge of the set of 
   shared forwarding paths rooted on the destination node. 
    
   Use of a Path Computation Server or other planning style of tool with 
   more complete knowledge of the network configuration may wish to 
   impose pre-selection of shared forwarding multiplexes to use for both 
   directions (Dave: Does this correct the typo). In this scenario the 
   originating switch uses the SUGGESTED LABEL and UPSTREAM LABEL 
   objects to indicate complete selection of the shared forwarding 
   multiplexes at both ends. This may also result in the establishment 
   of a new VID/DMAC path as the SUGGESTED LABEL object may legitimately 
   refer to a path that does not yet exist. 
    
11.2.3  Path Maintenance 
    
   Make before break procedures can be employed to modify the 
   characteristics of a P2P Ethernet LSP. As described in [RSVP-TE], 
   the LSP ID in the sender template is updated as the new path is 
   signaled. The procedures (including those for shared forwarding) are 
   identical to those employed in establishing a new LSP, with the 
   extended tunnel ID in the signaling exchange ensuring that double 
   booking of the associated resources does not occur. 
 
Fedyk et al.             Expires December 2006               Page 20 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
    
   Where individual paths in a protection group are modified, signaling 
   procedures may be combined with PS coordination to administratively 
   force PS switching operations such that modifications are only ever 
   performed on the protection path. 
    
11.3 P2MP VID/MAC Connections 
    
11.3.1 Setup procedures 
   The multicast DMAC is administered from a central pool of multicast 
   addresses and the VLAN selected from the configured VID/MAC range. 
   The P2MP tree is constructed via incremental addition of leaves to 
   the tree in signaling exchange where the root is the originating 
   switch (as per (MPLS-P2MP). The multicast DMAC and VID are encoded in 
   the suggested label object using the Ethernet label encoding. 
    
   Where a return path is required the unicast MAC corresponding to the 
   originating interface and a VID selected from the configured VID/MAC 
   range is encoded as an Ethernet label in the upstream label object. 
    
11.3.2  Maintenance Procedures 
 
   Maintenance and modification to a P2MP tree can be achieved by a 
   number of means. The preferred technique being to modify existing 
   VLAN configuration vs. assignment of a new label and completely 
   constructing a new tree.  
    
   Make before break on a live tree reusing existing label assignments 
   requires a 1:1 or 1+1 construct. The protection switch state of the 
   traffic is forced on the working tree and locked (PS not allowed) 
   while the backup tree is modified. Explicit path tear of leaves to 
   be modified is required to ensure no loops are left behind as 
   artifacts of tree modification. Once modifications are complete, a 
   forced switch to the backup tree occurs and the original tree may be 
   similarly modified. This also suggests that 1+1 or 1:1 resilience 
   can be achieved for P2MP trees for any single failure (switch on any 
   failure and use restoration techniques to repair the failed tree). 
    
11.4    P2MP VID Trees 
    
11.4.1  Setup Procedures 
 
   The VID is administered from the central pool of VLAN IDs 
   corresponding to the configured VID range. The P2MP VID tree is 
   constructed via incremental addition of leaves to the tree in 
   signaling exchange where the root is the originating switch as per 
   [MPLS-P2MP]. 
    
   Where (*,*) connectivity is to be configured a single VID is employed 
   and encoded as an Ethernet label in the suggested label object with 
   MAC address set to zero. 
    

 
Fedyk et al.             Expires December 2006               Page 21 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
   Where communication is to be constrained to root to leaves and leaves 
   to root only, asymmetrical VID configuration is used with the 
   suggested label object encoding the root to leaf VID and the upstream 
   label object encoding the leaf to root VID. 
    
11.4.2  Maintenance procedures 
 
   Maintenance and modification to a P2MP VID tree can be achieved by a 
   number of means. The preferred technique being to move traffic off 
   the tree, modify the tree and then shift traffic back to the tree. 
   This ensures that there are no transient loops in the tree that are 
   artifacts of interactions of the GMPLS control plane, soft state and 
   the Ethernet data plane. 
    
   Make before break on a live tree requires a 1:1 or 1+1 construct. 
   The protection switch state of the traffic is forced on the working 
   tree and locked (PS not allowed) while the backup tree is modified. 
   Explicit path tear of leaves to be modified is required to ensure no 
   loops are left behind as artifacts of tree modification. Once 
   modifications are complete, a forced switch to the backup tree 
   occurs and the original tree may be similarly modified. This also 
   suggests that 1+1 or 1:1 resilience can be achieved for P2MP trees 
   for any single failure (switch on any failure and use restoration 
   techniques to repair the failed tree). 
 
    
11.5    OAM MEP ID and MA ID synchronization 
    
   The Maintenance end point IDs (MEP IDs) and maintenance association 
   IDs for the switched path endpoints can be synchronized using the 
   ETH-MCC (maintenance communication channel) transaction set once the 
   switched path has been established. 
    
   MEPs are located at the endpoints of the Ethernet LSP. Typical 
   configuration associated with a MEP is Maintenance Domain Name, 
   Short Maintenance Association Name, and MA Level, MEP ID, and CCM 
   transmission rate (when ETH-CC functionality is desired). As part of 
   the synchronization, it is verified that the Maintenance Domain 
   Name, Short Maintenance Association Name, MA Level, and CCM 
   transmission rate are the same. It is also determined that MEP IDs 
   are unique for each MEP. 
    
   Server MEPs can be considered at the intermediate points of the PBT 
   network. Upon network failures (e.g. physical link failures), the 
   Server MEPs can initiate the unicast AIS frames for each Ethernet 
   LSP end-point that is present in the forwarding table. The only 
   configuration required at the Server MEPs is the MA Level which 
   should be the same as the MA Level configured at the Ethernet LSP 
   MEPs. 
    
   Besides the unicast CCM and AIS functionality, the PBT MEPs can also 
   offer the LBM/LBR and LMM/LMR functionalities for on-demand 
   connectivity verification and loss measurement purposes. 
 
Fedyk et al.             Expires December 2006               Page 22 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
    
11.6    Protection Paths 
    
   When protection is used for path recovery it is required to 
   associate the working and protection paths into a protection group. 
   This is achieved as defined in [RECOVERY_SIG] using the ASSOCIATION 
   and PROTECTION objects. Protection may be used for P2P VID/MAC, P2MP 
   VID/MAC and P2MP VID configured modes of operation. The 'P' bit in 
   the protection object indicates the role (working or protection) of 
   the LSP currently being signaled. 
    
   If the initiating switch wishes to use G.8031 [G-8031] data plane 
   protection switching coordination (vs. control plane notifications), 
   it sets the N bit to 1 in the protection object. This must be 
   consistently applied for all paths associated as a protection group. 
    
   If the terminating switch does not support G.8031, the error 
   "Admission Control Failure/Unsupported Notification Type" is used.  
 
12. Error conditions 
    
   The following errors have been identified as being unique to these 
   procedures and in addition to those already defined. This will be 
   addressed in a proper IANA considerations section in a future 
   version of the document: 
    
12.1    Invalid VID value for configured VID/MAC range 
    
   The originator of the error is not configured to use the VID value 
   in conjunction with GMPLS signaling of VID/MAC tuples. This may be 
   any switch along the path. 
    
12.2    Invalid VID value for configured VID range 
    
12.3    Invalid MAC Address 
     
12.4    Invalid ERO for Upstream Label Object 
     
    The ERO offered has discontinuities with the identified VID/MAC 
    path in the UPSTREAM LABEL object. 
     
12.5    Invalid ERO for Suggested Label Object 
   The ERO offered has discontinuities with the identified VID/MAC path 
   in the SUGGESTED LABEL object.  
    
12.6    Switch is not IVL capable 
    
12.7    Switch is not SVL capable 
    
12.8    Switch is not Asymmetric VID capable 
    


 
Fedyk et al.             Expires December 2006               Page 23 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
12.9    Invalid VID in upstream label object 
    The VID in the upstream label object for the "asymmetrical VID" 
    P2MP tree did not correspond to the VID used in previous 
    transactions. 
     
     
13. 
   Security Considerations 
   The architecture assumes that the GMPLS controlled Ethernet subnet 
   consists of trusted devices and that the UNI ports to the domain are 
   untrusted. Care is required to ensure untrusted access to the trusted 
   domain does not occur. Where GMPLS is applied to the control of VLAN 
   only, the commonly known techniques for mitigation of Ethernet DOS 
   attacks may be required on UNI ports. 
    
14. IANA Considerations 
    
   New values are required for signaling and error codes as indicated. 
   This section will be completed in a later version. 
    
15. References 
    
15.1 Normative References 
 
   [CCAMP-ETHERNET] Papadimitriou, D. et.al, "A Framework for 
      Generalized MPLS (GMPLS) Ethernet", internet draft, draft-
      papadimitriou-ccamp-gmpls-ethernet-framework-00.txt , June 2005  
    
   [GMPLS-SIGNALING] Berger, L. (editor), "Generalized MPLS -Signaling 
      Functional Description", January 2003, RFC3471. 
    
   [GMPLS-ROUTING] Kompella, K., Rekhter, Y., "Routing Extensions in 
      Support of Generalized MPLS", RFC 4202, October 2005 
    
   [GMPLS-RSVP] Berger, L. et.al., "Generalized Multi-Protocol Label  
      Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic  
      Engineering (RSVP-TE) Extensions", IETF RFC 3473, January 2003. 
    
    
15.2 Informative References 
    
   [DS-COLOR] Aboul-Magd, O. et.al. "A Differentiated Service Two-Rate,  
      Three-Color Marker with Efficient Handling of in-Profile Traffic",  
      IETF RFC 4115, July 2005 
    
   [G-8031] ITU-T Draft Recommendation G.8031, Ethernet Protection 
      Switching. 
     
   [GMPLS-ARCH] E. Mannie, Ed., "Generalized Multi-Protocol Label 
      Switching (GMPLS) Architecture", RFC 3495. 
    
   [IEEE 802.1ab] "IEEE Draft Standard for Local and Metropolitan Area  
      Networks, Station and Media Access Control Connectivity  
      Discovery". 
 
Fedyk et al.             Expires December 2006               Page 24 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
                          
   [IEEE 802.1ag] "IEEE standard for Connectivity Fault Management", 
      work in progress. 
    
   [IEEE 802.1ah] "IEEE standard for Provider Backbone Bridges", work in 
      progress. 
    
   [LMP] Lang. J. Editor, "Link Management Protocol (LMP)" work in 
      progress. 
    
   [MEF.6] The Metro Ethernet Forum MEF 6 (2004), "Ethernet Services 
      Definitions - Phase I". 
 
   [MEF.10] The Metro Ethernet Forum MEF 10 (2004), "Ethernet Services 
      Attributes Phase 1". 
    
   [MPLS-DS] Le Faucheur, F. et.al., "Multi-Protocol Label Switching 
      (MPLS) Support of Differentiated Services" IETF RFC 3270, May 
      2002. 
    
   [MPLS-P2MP] Aggarwal, R. Ed., "Extensions to RSVP-TE for Point to 
      Multipoint TE LSPs", work in progress. 
    
   [MYERS] Myers et.al. "Rethinking the service model, scaling Ethernet 
      to a million nodes", http://100x100network.org/papers/myers-   
      hotnets2004.pdf. 
    
   [PATH-COMP] Farrel, A. et.al., "Path Computation Element (PCE) 
      Architecture", work in progress. 
    
   [PWoPBT] Allan et.al., "Pseudo Wires over Provider Backbone 
      Transport", draft-allan-pw-o-pbt-00.txt, work in progress. 
    
   [PWE] Bryant, S., Pate, P. et al., "Pseudo Wire Emulation Edge-to 
      Edge (PWE3) Architecture", IETF RFC 3985, March 2005. 
    
   [RECOVERY_SIG] Lang et.al., "RSVP-TE Extensions in support of End-
      to-End Generalized Multi-Protocol Label Switching (GMPLS)-based 
      Recovery ", work in progress. 
    
   [RSVP-TE] Awduche et.al., "RSVP-TE: Extensions to RSVP for LSP  
      Tunnels, IETF RFC 3209, December 2001. 
    
   [Y.1731] ITU-T Draft Recommendation Y.1731(ethoam), " OAM Functions 
      and Mechanisms for Ethernet based Networks ", work in progress. 
    
    
16.  Author's Address 
 
   Don Fedyk 
   Nortel Networks 
   600 Technology Park Drive    Phone: +1-978-288-3041 
   Billerica, MA, 01821         Email: dwfedyk@nortel.com 
 
Fedyk et al.             Expires December 2006               Page 25 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
    
   David Allan 
   Nortel Networks              Phone: +1-613-763-6362 
   3500 Carling Ave.            Email: dallan@nortel.com 
   Ottawa, Ontario, CANADA 
    
   Greg Sunderwood 
   Bell Canada                  Phone: +1-604-648-7770 
   Suite 1500,                  Email: greg.sunderwood@gt.ca 
   1066 West Hastings Street 
   Vancouver, BC, CANADA 
   V6E 2X1 
    
   Himanshu Shah 
   Ciena                        Phone: 978-489-2196 
   35 Nagog Park,               Email: hshah@ciena.com 
   Acton, MA 01720               
    
17. Intellectual Property Statement 
    
   The IETF takes no position regarding the validity or scope of any 
   Intellectual Property Rights or other rights that might be claimed to 
   pertain to the implementation or use of the technology described in 
   this document or the extent to which any license under such rights 
   might or might not be available; nor does it represent that it has 
   made any independent effort to identify any such rights.  Information 
   on the procedures with respect to rights in RFC documents can be 
   found in BCP 78 and BCP 79. 
    
   Copies of IPR disclosures made to the IETF Secretariat and any 
   assurances of licenses to be made available, or the result of an 
   attempt made to obtain a general license or permission for the use of 
   such proprietary rights by implementers or users of this 
   specification can be obtained from the IETF on-line IPR repository at 
   http://www.ietf.org/ipr. 
    
   The IETF invites any interested party to bring to its attention any 
   copyrights, patents or patent applications, or other proprietary 
   rights that may cover technology that may be required to implement 
   this standard.  Please address the information to the IETF at 
   ietf-ipr@ietf.org. 
    
18. Disclaimer of Validity 
    
   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 
   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. 
    
    
 
Fedyk et al.             Expires December 2006               Page 26 
Internet Draft     draft-fedyk-gmpls-ethernet-pbt-00.txt 
                                    
19. Copyright Statement 
    
   Copyright (C) The Internet Society (2006).  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. 
    
    
20. Acknowledgments 
 
   The authors would like to thank Dinesh Mohan, Nigel Bragg, Stephen 
   Shew and Sandra Ballarte for their extensive contributions to this 
   document. 









































 
Fedyk et al.             Expires December 2006               Page 27 


PAFTECH AB 2003-20262026-04-23 01:38:58