One document matched: draft-sajassi-l2vpn-pbb-vpls-cmac-flush-00.txt



   Internet Working Group                                 Ali Sajassi 
   Internet Draft                                         Samer Salam 
   Intended Status: Standards                             Luyuan Fang 
                                                                Cisco 
                                                                       
                                                           Nabil Bitar 
                                                               Verizon 
                                                                       
                                                          Dinesh Mohan 
                                                                Nortel 
                                                                       
                                                         Raymond Zhang 
                                                       British Telecom 
   Expires: January 2009                                    July 2008 
                                                                         
    
      Customer MAC Address Flushing Mechanisms for Provider Backbone 
                            Bridging over VPLS  
              draft-sajassi-l2vpn-pbb-vpls-cmac-flush-00.txt 
    
   Status of this Memo 
    
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   Abstract 
    
   The scalability of H-VPLS (either with MPLS or Ethernet access 
   network) can be improved by incorporating Provider Backbone Bridge 
    
     
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   (PBB) functionality in VPLS access. 
    
   PBB introduces the notion of Backbone MAC (B-MAC) addresses vs. 
   Customer MAC (C-MAC) addresses, thereby leading to the requirement 
   for having MAC address flushing mechanisms for each. 
    
   This document discusses a C-MAC address flushing notification 
   mechanism to be used in VPLS networks that employ PBB technology. 
    
   Conventions 
    
   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....................................................2 
   2. Terminology.....................................................3 
   3. C-MAC vs. B-MAC Address Flushing in PBB Networks................4 
   4. C-MAC Address Flushing Mechanisms for H-VPLS with PBB Components6 
   4.1. H-VPLS with PBBN Access.......................................7 
   4.2. H-VPLS with MPLS Access: PBB U-PE.............................8 
   4.3. H-VPLS with MPLS Access: PBB N-PE.............................9 
   5. Message Format..................................................9 
   6. Advantages of Mechanism........................................11 
   7. Security Considerations........................................12 
   8. IANA Considerations............................................12 
   9. Intellectual Property Considerations...........................12 
   10. Full Copyright Statement......................................12 
   11. IPR Notice....................................................12 
   12. Normative References..........................................13 
   13. Informative References........................................13 
   14. Authors' Addresses............................................14 
    
    
    
   1.  
      Introduction 
    
   [P802.1ah] introduces a hierarchical network architecture where 
   customer MAC frames are encapsulated in "backbone" MAC frames before 
   being forwarded in the Provider Backbone Bridged Network (PBBN). 
   Customer MAC address (C-MAC) learning is performed only at the edge 
   of the PBBN (by I-Components) whereas all forwarding and learning in 
   the core of the network is performed on Backbone MAC addresses (B-
   MACs). This gives rise to two independent MAC address spaces: the C-
   MAC address space and the B-MAC address space. Consequently, MAC 
    
     
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   address flushing mechanisms are required for each address space, 
   independently.  
    
   [VPLS-PBB] analyzes the interoperability of Provider Backbone Bridge 
   (PBB) technology with VPLS. It also describes the scenarios and the 
   mechanisms for incorporating PBB functionality within H-VPLS with 
   existing MPLS access or IEEE 802.1ad (aka Q-in-Q) Ethernet access 
   and interoperability among them. 
    
   This document discusses the C-MAC address flushing notification 
   mechanism for VPLS networks that employ PBB technology, for both H-
   VPLS with native PBBN access and H-VPLS with MPLS access. Section 2 
   provides a summary of the terminology used throughout the document. 
   Section 3 discusses the difference between C-MAC address and B-MAC 
   address flushing in the context of PBB technology. Section 4 depicts 
   the C-MAC address flushing mechanisms for three representative 
   network use-case scenarios. Then, section 5 captures the message 
   formats. Finally, section 6 summarizes the advantages of the 
   solution. 
    
   2.  
      Terminology 
    
   802.1ad: IEEE specification for "Q-in-Q" encapsulation and bridging 
   of Ethernet frames. 
    
   802.1ah: IEEE specification for "MAC tunneling" encapsulation and 
   bridging of frames across a provider backbone bridged network. 
    
   B-BEB: A backbone edge bridge positioned at the edge of a provider 
   backbone bridged network. It contains a B-component that supports 
   bridging in the provider backbone based on B-MAC and B-TAG 
   information. 
    
   B-MAC: The backbone source and destination MAC address fields 
   defined in the 802.1ah provider MAC encapsulation header.   
    
   BCB: A backbone core bridge running in the core of a provider 
   backbone bridged network. It bridges frames based on B-TAG 
   information just as an 802.1ad provider bridge will bridge frames 
   based on a VLAN identifier (S-VLAN)    
    
   BEB: A backbone edge bridge positioned at the edge of a provider 
   backbone bridged network. It can contain an I-component, B-component 
   or both I and B components. 
    
   B-TAG:  field defined in the 802.1ah provider MAC encapsulation 
   header that conveys the backbone VLAN identifier information. The 
   format of the B-TAG field is the same as that of an 802.1ad S-TAG 
   field. 
    
    
     
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   B-VID: The specific VLAN identifier carried inside a B-TAG 
    
   C-MAC: Customer source or destination address used in a customer MAC 
   frame. 
    
   I-Component: A bridging component contained in a backbone edge 
   bridge that bridges in the customer space (customer MAC addresses, 
   S-VLAN)  
    
   IB-BEB: A backbone edge bridge positioned at the edge of a provider 
   backbone bridged network. It contains an I-component for bridging in 
   the customer space (customer MAC addresses, service VLAN IDs) and a 
   B-component for bridging the provider's backbone space (B-MAC, B-
   TAG). 
    
   I-BEB: A backbone edge bridged positioned at the edge of a provider 
   backbone bridged network. It contains an I-component for bridging in 
   the customer space (customer MAC addresses, service VLAN IDs). 
    
   I-SID: The 24-bit service instance field carried inside the I-TAG. 
   The I-SID defines the service instance that the frame should be 
   "mapped to". 
    
   I-TAG: A field defined in the 802.1ah provider MAC encapsulation 
   header that conveys the service instance information (I-SID) 
   associated with the frame.  
    
   PBB: Provider Backbone Bridge 
    
   PBBN: Provider Backbone Bridged Network 
    
   S-TAG: A field defined in the 802.1ad QinQ encapsulation header that 
   conveys the service VLAN identifier information (S-VLAN). 
    
   S-VLAN: The specific service VLAN identifier carried inside an S-TAG 
    
    
   3.  
      C-MAC vs. B-MAC Address Flushing in PBB Networks 
    
   In PBB networks, C-MAC address learning is confined to the edge of 
   the network, and performed on Backbone Edge Bridges that host an I-
   Component (i.e. I-BEBs and IB-BEBs) only. The I-Component builds a 
   mapping of C-MAC addresses to B-MAC addresses based on traffic 
   received from the PBB core. The core of the network forwards and 
   learns based only on B-MAC addresses; thus, it is completely 
   transparent to C-MAC addresses.  
    
   Any topology change in the customer's network, or its connection(s) 
   to the PBB network, that results in the reachability of a given C-
   MAC address moving from one I-Component to another I-Component 
   should trigger a C-MAC address flush notification for the affected 
    
     
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   service (I-SID). This is required to prevent potential traffic 
   black-holing due to a remote I-Component maintaining a stale C-MAC 
   to B-MAC address association. Such notification is only of interest 
   to remote bridges that host an I-Component for the service in 
   question (i.e. I-BEBs or IB-BEBs), but it is not of any value to 
   Backbone Core Bridges (BCBs). Furthermore, as long as the C-MAC 
   address flushing notification signals a topology change for a single 
   I-SID, it can be made completely transparent to B-BEBs as well. This 
   limits the scope of devices that need to transmit and/or handle C-
   MAC address flushing notifications to the edge of the PBB network, 
   and more precisely only to Backbone Edge Bridges with an I-Component 
   function (I-BEBs and IB-BEBs). This is shown as "Zone C" in Figure 1 
   below. 
    
   On the other hand, topology changes within the PBB network, which 
   result in the reach-ability of a given B-MAC address moving from one 
   port to another, should trigger a B-MAC address flushing 
   notification. This is of interest only to devices that learn and 
   forward based on B-MAC addresses. Hence, B-MAC address flushing 
   notifications can be confined to devices that implement BCB or B-
   Component (IB-BEB or B-BEB) functions in the PBB or the MPLS 
   network. This is depicted as "Zone B" in Figure 1. I-Components are 
   completely transparent to B-MAC address flushing mechanisms. 
    
                        C-MAC Flushing Scope --+ 
                                               | 
         +-------------------------------------|------------------+ 
         |               Zone C                V                  | 
         |       +----------------------------------------+       | 
         |       |  +----------------------------------+  |       | 
         |       |  |                                  |  |       |       
         | +---+ |  |  +---+   +---+    +---+   +---+  |  | +---+ | 
         | |I- | |  |  |B- |   |BCB|    |BCB|   |B- |  |  | |I- | | 
         | |BEB|-------|BEB|---|   |----|   |---|BEB|-------|BEB| | 
         | +---+ |  |  +---+   +---+\  /+---+   +---+  |  | +---+ | 
         |       |  |                \/                |  |       | 
         | +---+ |  |  +---+   +---+ /\ +---+   +---+  |  | +---+ | 
         | |I- | |  |  |B- |   |BCB|/  \|BCB|   |B- |  |  | |I- | | 
         | |BEB|-------|BEB|---|   |----|   |---|BEB|-------|BEB| | 
         | +---+ |  |  +---+   +---+    +---+   +---+  |  | +---+ | 
         |       |  |           |         |            |  |       | 
         |     +------+         |         |          +------+     | 
         |     |  IB- |         |         |          |  IB- |     | 
         |     |  BEB |---------+         +----------|  BEB |     | 
         |     +------+                              +------+     | 
         |       |  |    Zone B               ^        |  |       | 
         +-------+  +-------------------------|--------+  +-------+ 
                                              | 
    
     
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                       B-MAC Flushing Scope --+ 
 
     Figure 1: C-MAC and B-MAC Address Flushing Scope in PBB Networks 
    
   It is worth noting that devices which implement IB-BEB functions 
   will have to participate in both C-MAC as well as B-MAC address 
   flushing mechanisms because the subtended I-Component operates on C-
   MAC addresses whereas the subtended B-Component operates on B-MAC 
   addresses. This is the reason why IB-BEBs are shown to be part of 
   both Zones B and C in Figure 1 above. 
    
   For H-VPLS with PBB technology, including MPLS access and PBBN 
   access, both B-MAC address as well as C-MAC address flushing 
   notification mechanisms are required. In this context, B-MAC address 
   flushing notification can be accomplished via the use of LDP Address 
   Withdraw Message, as described in [RFC4762]. This is independent of 
   C-MAC flushing mechanisms, and as such, is considered outside the 
   scope of this document.  
    
   Having established the differentiation between C-MAC address and B-
   MAC address flushing in this section, we will now sharpen our focus 
   in the next section on C-MAC address flushing mechanisms for H-VPLS 
   with PBB technology. 
    
    
   4.  
      C-MAC Address Flushing Mechanisms for H-VPLS with PBB Components 
    
   As discussed in the previous section, C-MAC address flushing 
   notification need only be generated or processed by devices that 
   employ an I-Component function. Given that these devices are 
   confined to the edge of the PBB or the MPLS network, it is possible 
   to tunnel C-MAC address flushing messages transparently through the 
   PBB core bridges or N-PE devices without any loss of functionality. 
   As a matter of fact, this is indeed the preferred behavior for the 
   following reasons: 
     i) Devices operating on B-MAC addresses do not care about C-MAC 
        address flushing notification messages, and need not process 
        them. Actually having these devices process the C-MAC address 
        flush messages as control traffic places unnecessary burden on 
        the processors of these network nodes. 
     i
     i) Passing C-MAC address flushing notifications as regular data 
        frames (as opposed to control frames) within the PBB core 
        speeds up convergence, primarily because the forwarding can be 
        performed in the hardware that takes care of data traffic 
        switching. 
    
   Given the above, an in-band MAC address flushing notification 
   mechanism, that is native to the Ethernet layer, proves better 
   suited for C-MAC address flushing than an out-of-band mechanism. The 
    
     
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   C-MAC address flush notification message should be generated by the 
   device which hosts an I-Component that detects the topology change. 
   The message is encapsulated in a PBB frame that is tunneled as 
   regular data through the PBB core. The message must be flooded to 
   all edge devices that host an I-Component for the service 
   experiencing the topology change. These devices should remove the 
   PBB encapsulation from the frame and process the encapsulated C-MAC 
   address flush notification message. The processing involves flushing 
   the C-MAC address table entries for the affected service (I-SID). 
    
   In the following subsections, we demonstrate how the C-MAC address 
   flushing notification mechanism works in three representative 
   network architectures: section 4.1 focuses on H-VPLS with native 
   Ethernet PBBN access; whereas, sections 4.2 and 4.3 describe H-VPLS 
   with MPLS access and with PBB functions on the U-PE and N-PE, 
   respectively. 
    
   4.1.  
        H-VPLS with PBBN Access 
    
   Consider the network architecture of Figure 2 where native Ethernet 
   PBB aggregation networks are connected over a VPLS core. The CE 
   connected to the aggregation network on the left is dual-homed to 
   two PBB backbone edge bridges (IB-BEB1 and IB-BEB2). Assume that 
   initially the link to IB-BEB1 was the active CE uplink. If this link 
   fails, the CE will failover to the uplink connected to IB-BEB2 and 
   the latter will detect the topology change by virtue of the 
   redundancy mechanism running between the CE and the IB-BEB. The 
   details of this redundancy mechanism are outside the scope of this 
   document. The key point here is that the detection of the topology 
   change on IB-BEB2 will trigger that device to transmit C-MAC address 
   flushing notification messages for the affected services (I-SIDs). A 
   single C-MAC address flushing notification message should be 
   generated per I-SID. The message is encapsulated with the PBB 
   header, and is flooded to all other IB-BEBs that participate in the 
   affected I-SID, by using the multicast "Backbone Service Instance 
   Group Address" for that I-SID, as defined in [P802.1ah] section 
   26.4. The C-MAC flush notification message will be forwarded 
   transparently, like a regular data frame, by the bridges in the core 
   of the PBBN aggregation networks as well as by the VPLS PEs. When a 
   remote IB-BEB (e.g. IB-BEB3 and IB-BEB4), which participates in the 
   I-SID in question, receives the C-MAC flushing notification message, 
   it would process the frame by flushing the corresponding C-MAC 
   address table for the affected service (I-SID). 
    
    
    
    
    
    
    
    
    
     
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                                   +----------+ 
                +----+             |          |            +----+ 
               -|IB- |-------+     |  IP/MPLS |    +-------|IB- |  +--+ 
              / |BEB1|       |   +----+    +----+  |       |BEB3|--|CE| 
          +--+  +----+ PBBN  |   |VPLS|    |VPLS|  | PBBN  +----+  +--+ 
          |CE|    |   802.1ah|---| PE |    | PE |--| 802.1ah |      
          +--+  +----+       |   +----+    +----+  |       +----+  +--+ 
              \ |IB- |       |     | Backbone |    |       |IB- |--|CE| 
               -|BEB2|-------+     +----------+    +-------|BEB4|  +--+ 
                +----+                                     +----+ 
                     Figure 2: H-VPLS with PBBN Access 
    
    
   4.2.  
        H-VPLS with MPLS Access: PBB U-PE 
    
   In this architecture, MPLS access networks are connected over a VPLS 
   core, and PBB Backbone Edge Bridge functionality is embedded into 
   the U-PEs. Refer to Figure 3 below for an example. The CE in the 
   left access network is dual-homed to two U-PEs (U-PE1 and U-PE2). A 
   redundancy mechanism, the details of which are beyond the scope of 
   this document, determines that the CE uplink to U-PE1 is active 
   initially. A failure, e.g. of this uplink, triggers the redundancy 
   mechanism to activate the CE uplink to U-PE2 and to notify the 
   latter of the topology change. U-PE2 reacts to this notification by 
   transmitting C-MAC address flushing notification messages, similar 
   to what was described in Section 4.1. The C-MAC address flushing 
   notification message is forwarded by U-PE2 towards the N-PE, which 
   transparently floods the message over the full-mesh of pseudowires 
   in the VPLS core (for the VSI in question). Remote N-PEs which 
   receive those messages will again forward them as regular data 
   frames over the spoke pseudowires to the U-PEs. The U-PEs that 
   participate in the affected I-SID would respond to these messages by 
   flushing their local C-MAC address tables. Effectively, the C-MAC 
   address flush notification messages are treated as normal data 
   frames throughout the H-VPLS network, except at the U-PE nodes.  
    
           PBB 
           BEB                                               PBB 
            |                  +----------+                  BEB 
            V  +----------+    |          |                   | 
           +-----+   MPLS |    |    IP    |   +-----------+   | 
          /|U-PE1|  Access|    |   MPLS   |   |    MPLS   |   | 
         / +-----+      +----+ |   Core   | +----+ Access |   V 
     +--+      |        |VPLS|-|          |-|VPLS|       +-----+  +--+ 
     |CE|\ +-----+      |N-PE| |          | |N-PE|       |U-PE3|--|CE| 
     +--+ \|U-PE2|      +----+ |          | +----+       +-----+  +--+ 
           +-----+        |    |          |   |           | 
            ^  +----------+    +----------+   +-----------+ 
            | 
           PBB 
           BEB 
    
     
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          Figure 3: H-VPLS with MPLS Access Network and PBB U-PE 
    
    
   4.3.  
        H-VPLS with MPLS Access: PBB N-PE 
    
   Referring to Figure 4 below, in this network architecture the PBB 
   BEB functionality is implemented on the VPLS N-PE. Operation of the 
   C-MAC address flushing mechanism is similar to what was discussed in 
   the previous section, except that the messages are generated and 
   processed by the N-PEs instead of the U-PEs. 
    
    
    
                           PBB 
                           BEB              PBB 
                            |               BEB 
                            V                | 
                        +-----+ +----------+ |                 
               +--------|VPLS | |          | |                  
               |        |N-PE1|-|    IP    | | +-----------+    
               |        +-----+ |   MPLS   | V |     MPLS  |    
     +--+  +-----+  MPLS  |     |   Core   | +-----+ Access|    
     |CE|--|U-PE | Access |     |          |-|VPLS |      +-----+  +--+ 
     +--+  +-----+        |     |          | |N-PE3|      |U-PE |--|CE| 
               |        +-----+ |          | +-----+      +-----+  +--+ 
               |        |VPLS |-|          |   |           | 
               +--------|N-PE2| +----------+   +-----------+ 
                        +-----+ 
                            ^ 
                            | 
                           PBB 
                           BEB 
    
          Figure 4: H-VPLS with MPLS Access Network and PBB N-PE 
    
    
   5.  
      Message Format 
    
   The format of the C-MAC address flushing notification message is 
   based on a PBB-encapsulated Multi-VLAN Registration Protocol (MVRP) 
   PDU, as defined in [802.1ak]. This is shown in Figure 5 below. It 
   should be noted that generation or reception handling of this 
   message does NOT require a VPLS PE device (with PBB I-Component 
   functionality) to necessarily run the IEEE 802.1ak protocol stack. 
   This is primarily because all the fields of the encapsulated MVRP 
   PDU are fixed. It is sufficient for the VPLS PE device to 
   encapsulate the PDU with the right PBB header on transmission, and 
   react to the message by flushing the appropriate C-MAC address table 
   for the I-SID on reception. 
    
    
     
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           +--------------------+ 
           |       B-DA         | 
           +--------------------+ 
           |       B-SA         | 
           +--------------------+ 
           | EtherType = 0x88a8 | 
           +--------------------+ 
           |      B-VLAN        | 
           +--------------------+ 
           | EtherType = 0x88e7 | 
           +--------------------+ 
           |      I-SID         | 
           +--------------------+ 
           |       C-DA         | 
           +--------------------+ 
           |       C-SA         | 
           +--------------------+ 
           | EtherType = 0x88f5 | 
           +--------------------+ 
           |                    | 
           ~       MVRP PDU     ~ 
           |                    | 
           +--------------------+ 
    
       Figure 5: C-MAC Address Flushing Notification Message Format 
    
   B-DA: The Backbone Service Instance Group Address for the I-SID that 
   is experiencing the topology change, as defined in [P802.1ah] 
   section 26.4 
    
   B-SA: The B-MAC source address of the I-Component generating the 
   message. 
    
   B-VLAN: The B-VLAN used for the I-SID for which C-MAC addresses 
   should be flushed. 
    
   I-SID: The I-SID for which C-MAC addresses should be flushed. 
    
   C-DA: This should be set to 01-80-C2-00-00-21 if the Customer 
   Instance Ports (CIPs) encountering the topology change for the I-SID 
   in question are 802.1Q interfaces, and set to 01-80-C2-00-00-0D if 
   the CIPs are 802.1ad / Q-in-Q interfaces. Refer to [802.1ak] Table 
   8-1 and Table 10-1. 
    
   C-SA: The C-MAC address that uniquely identifies the I-Component. 
   This should not be the same as the B-SA in order to avoid any 
   confusion that may arise from using the same address value in both 
    
     
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   C-MAC and B-MAC address spaces. The value for this field can be set 
   to the port MAC address of any of the CIPs associated with the I-
   Component generating the C-MAC address flushing notification 
   message. 
    
   MVRP PDU: This is an MVRP PDU declaring "new" registrations for all 
   VLANs (1 to 4094). The format of this PDU is as shown in Figure 6 
   below. 
    
   No. Bits         Field                 Value 
        
             +--------------------+ 
      8      |  Protocol Version  |       0x00 
             +--------------------+ 
      8      |  AttributeType     |       0x01 
             +--------------------+ 
      8      |  AttributeLength   |       0x02 
          +- +--------------------+ -+ 
          |  |  LeaveAllEvent     |  |     
      16 -+  +--------------------+  +-   0x0ffe 
          |  |  NumberofValues    |  | 
          +- +--------------------+ -+ 
      16     |  FirstValue        |       0x01 
             +--------------------+  
      10920  |  Vector            |       0x00 (repeated 1365 times) 
             +--------------------+ 
      16     |  EndMark           |       0x0000 
             +--------------------+ 
    
                         Figure 6: MVRP PDU Format 
    
   The various fields of this PDU are standardized by IEEE as outlined 
   in [802.1ak]. 
    
    
   6.  
      Advantages of Mechanism 
    
   The C-MAC address flushing notification mechanism described in this 
   document has the following advantages: 
     i) It is completely transparent to all devices that operate on B-
        MAC addresses; e.g., is transparent to VPLS PE and N-PE in the 
        case of H-VPLS with PBBN access and the case of H-VPLS with 
        MPLS access (PBB on U-PE), respectively. 
     i
     i) Treating C-MAC address flushing notifications as regular data 
        frames (as opposed to control frames) within the PBB core and 
        the on the VPLS PEs / N-PEs speeds up convergence, primarily 
        because the forwarding can be performed in hardware, and no 
        software-based control-plane processing is involved. 
    
     
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     i
     i
      i) The mechanism applies to Tightly Coupled, Loosely Coupled as 
        well as Different Service Domains [VPLS-PBB]. This is because 
        each message carries a flush indication for a single I-SID, and 
        the value of the I-SID is encoded in the PBB header only. 
        Furthermore, I-SID translation, in the case of Different 
        Service Domains, can be performed in the normal data-path by 
        the hardware that handles regular data traffic. 
       
   7.  
      Security Considerations 
    
   There are no additional security aspects beyond those of VPLS/H-VPLS 
   that need to be discussed here.  
    
   8.  
      IANA Considerations 
    
   None. 
    
   9.  
      Intellectual Property Considerations 
    
   This document is being submitted for use in IETF standards 
   discussions. 
    
   10.  
       Full Copyright Statement 
 
   Copyright (C) The IETF Trust (2008). 
    
   This document is subject to the rights, licenses and restrictions 
   contained in BCP 78, and except as set forth therein, the authors 
   retain all their rights. 
    
   This document and the information contained herein are provided on 
   an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE 
   REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE 
   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 
   ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS 
   FOR A PARTICULAR PURPOSE. 
    
    
   11.  
       IPR Notice 
    
   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 
    
     
   Sajassi, et al.                                           [Page 12] 
    
    
   draft-sajassi-l2vpn-pbb-vpls-cmac-flush-00.txt            July 2008 
    
   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. 
    
    
   12.  
       Normative References 
    
   [P802.1ah] IEEE P802.1ah/D4.2, "Draft Standard for Local and 
      Metropolitan Area Networks - Virtual Bridged Local Area Networks 
      - Amendment 6: Provider Backbone Bridges", IEEE 802.1 
      Interworking Task Group, March, 2008. 
    
   [RFC4762] "Virtual Private LAN Service (VPLS) Using Label 
      Distribution Protocol (LDP) Signaling", RFC4762, January 2007 
 
   [802.1ak] IEEE Std. 802.1ak-2007, "IEEE Standard for Local and 
      metropolitan area networks - Virtual Bridged Local Area Networks 
      - Amendment 7: Multiple Registration Protocol", IEEE Computer 
      Society, June, 2007. 
    
   [802.1ad] IEEE Std. 802.1ad-2005, "IEEE Standard for Local and 
      metropolitan area networks - virtual Bridged Local Area Networks, 
      Amendment 4: Provider Bridges", IEEE Computer Society, May, 2006. 
    
    
    
    
   13.  
       Informative References 
    
   [VPLS-PBB] Sajassi et al., "VPLS Interoperability with Provider 
      Backbone Bridges", draft-sajassi-l2vpn-vpls-pbb-interop-02.txt, 
      work in progress, November, 2007. 
    
    
    
    
    
     
   Sajassi, et al.                                           [Page 13] 
    
    
   draft-sajassi-l2vpn-pbb-vpls-cmac-flush-00.txt            July 2008 
    
   14.  
       Authors' Addresses 
    
   Ali Sajassi 
   Cisco 
   170 West Tasman Drive 
   San Jose, CA  95134, US 
   Email: sajassi@cisco.com 
    
   Samer Salam 
   Cisco 
   595 Burrard Street, Suite 2123 
   Vancouver, BC V7X 1J1, Canada 
   Email: ssalam@cisco.com 
    
   Luyuan Fang 
   Cisco  
   300 Beaver Brook Road 
   Boxborough, MA  01719, US 
   Email: lufang@cisco.com 
    
   Nabil Bitar 
   Verizon Communications 
   Email : nabil.n.bitar@verizon.com  
    
   Dinesh Mohan 
   Nortel 
   3500 Carling Ave 
   Ottawa, ON K2H8E9 
   Email: mohand@nortel.com 
    
   Raymond Zhang 
   British Telecom 
   2160 E. Grand Avenue 
   El Segundo, CA 90245 
   Email: raymond.zhang@bt.com 
    
    
     
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