Network Working Group                                     M-K. Shin, Ed.
Request for Comments: 5181                                          ETRI
Category: Informational                                         Y-H. Han
                                                                    KUT
                                                               S-E. Kim
                                                                     KT
                                                              D. Premec
                                                         Siemens Mobile
                                                               May 2008


             IPv6 Deployment Scenarios in 802.16 Networks

Status of This Memo

  This memo provides information for the Internet community.  It does
  not specify an Internet standard of any kind.  Distribution of this
  memo is unlimited.

Abstract

  This document provides a detailed description of IPv6 deployment and
  integration methods and scenarios in wireless broadband access
  networks in coexistence with deployed IPv4 services.  In this
  document, we will discuss the main components of IPv6 IEEE 802.16
  access networks and their differences from IPv4 IEEE 802.16 networks
  and how IPv6 is deployed and integrated in each of the IEEE 802.16
  technologies.

Table of Contents

  1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  2
    1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  2
  2.  Deploying IPv6 in IEEE 802.16 Networks . . . . . . . . . . . .  3
    2.1.  Elements of IEEE 802.16 Networks . . . . . . . . . . . . .  3
    2.2.  Scenarios and IPv6 Deployment  . . . . . . . . . . . . . .  3
      2.2.1.  Mobile Access Deployment Scenarios . . . . . . . . . .  4
      2.2.2.  Fixed/Nomadic Deployment Scenarios . . . . . . . . . .  8
    2.3.  IPv6 Multicast . . . . . . . . . . . . . . . . . . . . . . 10
    2.4.  IPv6 QoS . . . . . . . . . . . . . . . . . . . . . . . . . 11
    2.5.  IPv6 Security  . . . . . . . . . . . . . . . . . . . . . . 11
    2.6.  IPv6 Network Management  . . . . . . . . . . . . . . . . . 11
  3.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
  4.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
  5.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
    5.1.  Normative References . . . . . . . . . . . . . . . . . . . 12
    5.2.  Informative References . . . . . . . . . . . . . . . . . . 13




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1.  Introduction

  As the deployment of IEEE 802.16 access networks progresses, users
  will be connected to IPv6 networks.  While the IEEE 802.16 standard
  defines the encapsulation of an IPv4/IPv6 datagram in an IEEE 802.16
  Media Access Control (MAC) payload, a complete description of IPv4/
  IPv6 operation and deployment is not present.  The IEEE 802.16
  standards are limited to L1 and L2, so they may be used within any
  number of IP network architectures and scenarios.  In this document,
  we will discuss the main components of IPv6 IEEE 802.16 access
  networks and their differences from IPv4 IEEE 802.16 networks and how
  IPv6 is deployed and integrated in each of the IEEE 802.16
  technologies.

  This document extends the work of [RFC4779] and follows the structure
  and common terminology of that document.

1.1.  Terminology

  The IEEE 802.16-related terminologies in this document are to be
  interpreted as described in [RFC5154].

  o  Subscriber Station (SS): An end-user equipment that provides
     connectivity to the 802.16 networks.  It can be either fixed/
     nomadic or mobile equipment.  In a mobile environment, SS
     represents the Mobile Subscriber Station (MS) introduced in
     [IEEE802.16e].

  o  Base Station (BS): A generalized equipment set providing
     connectivity, management, and control between the subscriber
     station and the 802.16 networks.

  o  Access Router (AR): An entity that performs an IP routing function
     to provide IP connectivity for a subscriber station (SS or MS).

  o  Connection Identifier (CID): A 16-bit value that identifies a
     connection to equivalent peers in the 802.16 MAC of the SS(MS) and
     BS.

  o  Ethernet CS (Convergence Sublayer): 802.3/Ethernet CS-specific
     part of the Packet CS defined in 802.16 STD.

  o  IPv6 CS (Convergence Sublayer): IPv6-specific subpart of the
     Packet CS, Classifier 2 (Packet, IPv6) defined in 802.16 STD.







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2.  Deploying IPv6 in IEEE 802.16 Networks

2.1.  Elements of IEEE 802.16 Networks

  [IEEE802.16e] is an air interface for fixed and mobile broadband
  wireless access systems.  [IEEE802.16] only specifies the convergence
  sublayers and the ability to transport IP over the air interface.
  The details of IPv6 (and IPv4) operations over IEEE 802.16 are
  defined in the 16ng WG.  The IPv6 over IPv6 CS definition is already
  an approved specification [RFC5121].  IP over Ethernet CS in IEEE
  802.16 is defined in [IP-ETHERNET].

  Figure 1 illustrates the key elements of typical mobile 802.16
  deployments.

         Customer |     Access Provider    | Service Provider
         Premise  |                        | (Backend Network)

      +-----+            +----+     +----+   +--------+
      | SSs |--(802.16)--| BS |-----|    |   | Edge   |   ISP
      +-----+            +----+     | AR |---| Router |==>Network
                                 +--|    |   | (ER)   |
                                 |  +----+   +--------+
      +-----+            +----+  |                |  +------+
      | SSs |--(802.16)--| BS |--+                +--|AAA   |
      +-----+            +----+                      |Server|
                                                     +------+

            Figure 1: Key Elements of IEEE 802.16(e) Networks

2.2.  Scenarios and IPv6 Deployment

  [IEEE802.16] specifies two modes for sharing the wireless medium:
  point-to-multipoint (PMP) and mesh (optional).  This document only
  focuses on the PMP mode.

  Some of the factors that hinder deployment of native IPv6 core
  protocols are already introduced by [RFC5154].

  There are two different deployment scenarios: fixed and mobile access
  deployment scenarios.  A fixed access scenario substitutes for
  existing wired-based access technologies such as digital subscriber
  lines (xDSL) and cable networks.  This fixed access scenario can
  provide nomadic access within the radio coverages, which is called
  the Hot-zone model.  A mobile access scenario exists for the new
  paradigm of transmitting voice, data, and video over mobile networks.
  This scenario can provide high-speed data rates equivalent to the
  wire-based Internet as well as mobility functions equivalent to



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  cellular systems.  There are the different IPv6 impacts on
  convergence sublayer type, link model, addressing, mobility, etc.
  between fixed and mobile access deployment scenarios.  The details
  will be discussed below.  The mobile access scenario can be
  classified into two different IPv6 link models: shared IPv6 prefix
  link model and point-to-point link model.

2.2.1.  Mobile Access Deployment Scenarios

  Unlike IEEE 802.11, the IEEE 802.16 BS can provide mobility functions
  and fixed communications.  [IEEE802.16e] has been standardized to
  provide mobility features on IEEE 802.16 environments.  IEEE 802.16
  BS might be deployed with a proprietary backend managed by an
  operator.

  There are two possible IPv6 link models for mobile access deployment
  scenarios: shared IPv6 prefix link model and point-to-point link
  model [RFC4968].  There is always a default access router in the
  scenarios.  There can exist multiple hosts behind an MS (networks
  behind an MS may exist).  The mobile access deployment models, Mobile
  WiMax and WiBro, fall within this deployment model.

  (1) Shared IPv6 Prefix Link Model

  This link model represents the IEEE 802.16 mobile access network
  deployment where a subnet consists of only single AR interfaces and
  multiple MSs.  Therefore, all MSs and corresponding AR interfaces
  share the same IPv6 prefix as shown in Figure 2.  The IPv6 prefix
  will be different from the interface of the AR.

    +-----+
    | MS1 |<-(16)-+
    +-----+       |    +-----+
    +-----+       +----| BS1 |--+
    | MS2 |<-(16)-+    +-----+  |
    +-----+                     |  +-----+    +--------+
                                +->| AR  |----| Edge   |    ISP
    +-----+                     |  +-----+    | Router +==>Network
    | MS3 |<-(16)-+    +-----+  |             +--------+
    +-----+       +----| BS2 |--+
    +-----+       |    +-----+
    | MS4 |<-(16)-+
    +-----+

                 Figure 2: Shared IPv6 Prefix Link Model






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  (2) Point-to-Point Link Model

  This link model represents IEEE 802.16 mobile access network
  deployments where a subnet consists of only a single AR, BS, and MS.
  That is, each connection to a mobile node is treated as a single
  link.  Each link between the MS and the AR is allocated a separate,
  unique prefix or a set of unique prefixes by the AR.  The point-to-
  point link model follows the recommendations of [RFC3314].

     +-----+            +-----+     +-----+
     | MS1 |<-(16)------|     |---->|     |
     +-----+            | BS1 |     |     |
     +-----+            |     |     |     |    +--------+
     | MS2 |<-(16)------|     |---->|     |----| Edge   |    ISP
     +-----+            +-----+     |     |    | Router +==>Network
                                    | AR  |    +--------+
     +-----+            +-----+     |     |
     | MS3 |<-(16)------|     |---->|     |
     +-----+            | BS2 |     |     |
     +-----+            |     |     |     |
     | MS4 |<-(16)------|     |---->|     |
     +-----+            +-----+     +-----+

                   Figure 3: Point-to-Point Link Model

2.2.1.1.  IPv6-Related Infrastructure Changes

  IPv6 will be deployed in this scenario by upgrading the following
  devices to dual stack: MS, AR, and ER.  In this scenario, IEEE 802.16
  BSs have only MAC and PHY (Physical Layer) layers without router
  functionality and operate as a bridge.  The BS should support IPv6
  classifiers as specified in [IEEE802.16].

2.2.1.2.  Addressing

  An IPv6 MS has two possible options to get an IPv6 address.  These
  options will be equally applied to the other scenario below (Section
  2.2.2).

  (1) An IPv6 MS can get the IPv6 address from an access router using
  stateless auto-configuration.  In this case, router discovery and
  Duplicate Address Detection (DAD) operation should be properly
  operated over an IEEE 802.16 link.








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  (2) An IPv6 MS can use Dynamic Host Configuration Protocol for IPv6
  (DHCPv6) to get an IPv6 address from the DHCPv6 server.  In this
  case, the DHCPv6 server would be located in the service provider core
  network, and the AR should provide a DHCPv6 relay agent.  This option
  is similar to what we do today in case of DHCPv4.

  In this scenario, a router and multiple BSs form an IPv6 subnet, and
  a single prefix is allocated to all the attached MSs.  All MSs
  attached to the same AR can be on the same IPv6 link.

  As for the prefix assignment, in the case of the shared IPv6 prefix
  link model, one or more IPv6 prefixes are assigned to the link and
  are hence shared by all the nodes that are attached to the link.  In
  the point-to-point link model, the AR assigns a unique prefix or a
  set of unique prefixes for each MS.  Prefix delegation can be
  required if networks exist behind an MS.

2.2.1.3.  IPv6 Transport

  In an IPv6 subnet, there are always two underlying links: one is the
  IEEE 802.16 wireless link between the MS and BS, and the other is a
  wired link between the BS and AR.

  IPv6 packets can be sent and received via the IP-specific part of the
  packet convergence sublayer.  The Packet CS is used for the transport
  of packet-based protocols, which include Ethernet and Internet
  Protocol (IPv4 and IPv6).  Note that in this scenario, IPv6 CS may be
  more appropriate than Ethernet CS to transport IPv6 packets, since
  there is some overhead of Ethernet CS (e.g., Ethernet header) under
  mobile access environments.  However, when PHS (Payload Header
  Suppression) is deployed, it mitigates this overhead through the
  compression of packet headers.  The details of IPv6 operations over
  the IP-specific part of the packet CS are defined in [RFC5121].

  Simple or complex network equipment may constitute the underlying
  wired network between the AR and the ER.  If the IP-aware equipment
  between the AR and the ER does not support IPv6, the service
  providers can deploy IPv6-in-IPv4 tunneling mechanisms to transport
  IPv6 packets between the AR and the ER.

  The service providers are deploying tunneling mechanisms to transport
  IPv6 over their existing IPv4 networks as well as deploying native
  IPv6 where possible.  Native IPv6 should be preferred over tunneling
  mechanisms as native IPv6 deployment options might be more scalable
  and provide the required service performance.  Tunneling mechanisms
  should only be used when native IPv6 deployment is not an option.
  This can be equally applied to other scenarios below (Section 2.2.2).




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2.2.1.4.  Routing

  In general, the MS is configured with a default route that points to
  the AR.  Therefore, no routing protocols are needed on the MS.  The
  MS just sends to the AR using the default route.

  The AR can configure multiple links to the ER for network
  reliability.  The AR should support IPv6 routing protocols such as
  OSPFv3 [RFC2740] or Intermediate System to Intermediate System
  (IS-IS) for IPv6 when connected to the ER with multiple links.

  The ER runs the Interior Gateway Protocol (IGP) such as OSPFv3 or
  IS-IS for IPv6 in the service provider network.  The routing
  information of the ER can be redistributed to the AR.  Prefix
  summarization should be done at the ER.

2.2.1.5.  Mobility

  There are two types of handovers for the IEEE 802.16e networks: link
  layer handover and IP layer handover.  In a link layer handover, BSs
  involved in the handover reside in the same IP subnet.  An MS only
  needs to reestablish a link layer connection with a new BS without
  changing its IP configuration, such as its IP address, default
  router, on-link prefix, etc.  The link layer handover in IEEE 802.16e
  is by nature a hard handover since the MS has to cut off the
  connection with the current BS at the beginning of the handover
  process and cannot resume communication with the new BS until the
  handover completes [IEEE802.16e].  In an IP layer handover, the BSs
  involved reside in different IP subnets, or in different networks.
  Thus, in an IP layer handover, an MS needs to establish both a new
  link layer connection, as in a link layer handover, and a new IP
  configuration to maintain connectivity.

  IP layer handover for MSs is handled by Mobile IPv6 [RFC3775].
  Mobile IPv6 defines that movement detection uses Neighbor
  Unreachability Detection to detect when the default router is no
  longer bidirectionally reachable, in which case the mobile node must
  discover a new default router.  Periodic Router Advertisements for
  reachability and movement detection may be unnecessary because the
  IEEE 802.16 MAC provides the reachability by its ranging procedure
  and the movement detection by the Handoff procedure.

  Mobile IPv6 alone will not solve the handover latency problem for the
  IEEE 802.16e networks.  To reduce or eliminate packet loss and to
  reduce the handover delay in Mobile IPv6, therefore, Fast Handover
  for Mobile IPv6 (FMIPv6) [RFC4068] can be deployed together with
  MIPv6.  To perform predictive packet forwarding, the FMIPv6's IP
  layer assumes the presence of handover-related triggers delivered by



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  the IEEE 802.16 MAC layers.  Thus, there is a need for cross-layering
  design to support proper behavior of the FMIPv6 solution.  This issue
  is also discussed in [MIPSHOP-FH80216E].

  Also, [IEEE802.16g] defines L2 triggers for link status such as
  link-up, link-down, and handoff-start.  These L2 triggers may make
  the Mobile IPv6 or FMIPv6 procedure more efficient and faster.

  In addition, due to the problems caused by the existence of multiple
  convergence sublayers [RFC4840], the mobile access scenarios need
  solutions about how roaming will work when forced to move from one CS
  to another (e.g., IPv6 CS to Ethernet CS).  Note that, at this phase,
  this issue is the out of scope of this document.

2.2.2.  Fixed/Nomadic Deployment Scenarios

  The IEEE 802.16 access networks can provide plain Ethernet end-to-end
  connectivity.  This scenario represents a deployment model using
  Ethernet CS.  A wireless DSL deployment model is an example of a
  fixed/nomadic IPv6 deployment of IEEE 802.16.  Many wireless Internet
  service providers (wireless ISPs) have planned to use IEEE 802.16 for
  the purpose of high-quality broadband wireless services.  A company
  can use IEEE 802.16 to build up a mobile office.  Wireless Internet
  spreading through a campus or a cafe can also be implemented with it.

           +-----+                        +-----+    +-----+    ISP 1
           | SS1 |<-(16)+              +->| AR1 |----| ER1 |===>Network
           +-----+      |              |  +-----+    +-----+
           +-----+      |     +-----+  |
           | SS2 |<-(16)+-----| BS1 |--|
           +-----+            +-----+  |  +-----+    +-----+    ISP 2
                                       +->| AR2 |----| ER2 |===>Network
+-----+    +-----+            +-----+  |  +-----+    +-----+
|Hosts|<-->|SS/GW|<-(16)------| BS2 |--+
+-----+    +-----+            +-----+
   This network
behind SS may exist

               Figure 4: Fixed/Nomadic Deployment Scenario

  This scenario also represents IEEE 802.16 network deployment where a
  subnet consists of multiple MSs and multiple interfaces of the
  multiple BSs.  Multiple access routers can exist.  There exist
  multiple hosts behind an SS (networks behind an SS may exist).  When
  802.16 access networks are widely deployed as in a Wireless Local
  Area Network (WLAN), this case should also be considered.  The Hot-
  zone deployment model falls within this case.




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  While Figure 4 illustrates a generic deployment scenario, the
  following, Figure 5, shows in more detail how an existing DSL ISP
  would integrate the 802.16 access network into its existing
  infrastructure.

+-----+                        +---+      +-----+    +-----+    ISP 1
| SS1 |<-(16)+                 |   |  +-->|BRAS |----| ER1 |===>Network
+-----+      |                 |  b|  |   +-----+    +-----+
+-----+      |     +-----+     |E r|  |
| SS2 |<-(16)+-----| BS1 |-----|t i|  |
+-----+            +-----+     |h d|--+
                               |  g|  |   +-----+    +-----+    ISP 2
+-----+            +-----+     |  e|  +-->|BRAS |----| ER2 |===>Network
| SS3 |<-(16)------| BS2 |-----|   |  |   +-----+    +-----+
+-----+            +-----+     +---+  |
                                      |
+-----+            +-----+            |
| TE  |<-(DSL)-----|DSLAM|------------+
+-----+            +-----+

   Figure 5: Integration of 802.16 Access into the DSL Infrastructure

  In this approach, the 802.16 BS is acting as a DSLAM (Digital
  Subscriber Line Access Multiplexer).  On the network side, the BS is
  connected to an Ethernet bridge, which can be separate equipment or
  integrated into the BRAS (Broadband Remote Access Server).

2.2.2.1.  IPv6-Related Infrastructure Changes

  IPv6 will be deployed in this scenario by upgrading the following
  devices to dual stack: MS, AR, ER, and the Ethernet bridge.  The BS
  should support IPv6 classifiers as specified in [IEEE802.16].

  The BRAS in Figure 5 is providing the functionality of the AR.  An
  Ethernet bridge is necessary for protecting the BRAS from 802.16 link
  layer peculiarities.  The Ethernet bridge relays all traffic received
  through the BS to its network side port(s) connected to the BRAS.
  Any traffic received from the BRAS is relayed to the appropriate BS.
  Since the 802.16 MAC layer has no native support for multicast (and
  broadcast) in the uplink direction, the Ethernet bridge will
  implement multicast (and broadcast) by relaying the multicast frame
  received from the MS to all of its ports.  The Ethernet bridge may
  also provide some IPv6-specific functions to increase link efficiency
  of the 802.16 radio link (see Section 2.2.2.3).







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2.2.2.2.  Addressing

  One or more IPv6 prefixes can be shared to all the attached MSs.
  Prefix delegation can be required if networks exist behind the SS.

2.2.2.3.  IPv6 Transport

  Transmission of IPv6 over Ethernet CS follows [RFC2464] and does not
  introduce any changes to [RFC4861] and [RFC4862].  However, there are
  a few considerations in the viewpoint of operation, such as
  preventing periodic router advertisement messages from an access
  router and broadcast transmission, deciding path MTU size, and so on.
  The details about the considerations are described in [IP-ETHERNET].

2.2.2.4.  Routing

  In this scenario, IPv6 multi-homing considerations exist.  For
  example, if there exist two routers to support MSs, a default router
  must be selected.

  The Edge Router runs the IGP used in the SP network such as OSPFv3
  [RFC2740] or IS-IS for IPv6.  The connected prefixes have to be
  redistributed.  Prefix summarization should be done at the Edge
  Router.

2.2.2.5.  Mobility

  No mobility functions of Layer 2 and Layer 3 are supported in the
  fixed access scenario.  Like WLAN technology, however, nomadicity can
  be supported in the radio coverage without any mobility protocol.
  So, a user can access Internet nomadically in the coverage.

  Sometimes, service users can demand IP session continuity or home
  address reusability even in the nomadic environment.  In that case,
  Mobile IPv6 [RFC3775] may be used in this scenario even in the
  absence of Layer 2's mobility support.

2.3.  IPv6 Multicast

  [IP-ETHERNET] realizes IPv6 multicast support by Internet Group
  Management Protocol/Multicast Listener Discovery (IGMP/MLD) proxying
  [RFC4605] and IGMP/MLD snooping [RFC4541].  Additionally, it may be
  possible to efficiently implement multicast packet transmission among
  the multicast subscribers by means of IEEE 802.16 Multicast CIDs.
  However, such a protocol is not yet available and under development
  in WiMAX Forum.





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RFC 5181            IPv6 over IEEE 802.16 Scenarios             May 2008


2.4.  IPv6 QoS

  In IEEE 802.16 networks, a connection is unidirectional and has a
  Quality of Service (QoS) specification.  Each connection is
  associated with a single data service flow, and each service flow is
  associated with a set of QoS parameters in [IEEE802.16].  The QoS-
  related parameters are managed using the Dynamic Service Addition
  (DSA) and Dynamic Service Change (DSC) MAC management messages
  specified in [IEEE802.16].  The [IEEE802.16] provides QoS
  differentiation for the different types of applications by five
  scheduling services.  Four scheduling services are defined in 802.16:
  Unsolicited Grant Service (UGS), real-time Polling Service (rtPS),
  non-real-time Polling Service (nrtPS), and Best Effort (BE).  A fifth
  scheduling service is Extended Real-time Polling Service (ertPS),
  defined in [IEEE802.16e].  It is required to define IP layer quality
  of service mapping to MAC layer QoS types [IEEE802.16],
  [IEEE802.16e].

2.5.  IPv6 Security

  When initiating the connection, an MS is authenticated by the
  Authentication, Authorization, and Accounting (AAA) server located at
  its service provider network.  To achieve that, the MS and the BS use
  Privacy Key Management [IEEE802.16],[IEEE802.16e], while the BS
  communicates with the AAA server using a AAA protocol.  Once the MS
  is authenticated with the AAA server, it can associate successfully
  with the BS and acquire an IPv6 address through stateless auto-
  configuration or DHCPv6.  Note that the initiation and authentication
  process is the same as the one used in IPv4.

2.6.  IPv6 Network Management

  [IEEE802.16f] includes the management information base for IEEE
  802.16 networks.  For IPv6 network management, the necessary
  instrumentation (such as MIBs, NetFlow Records, etc.) should be
  available.

  Upon entering the network, an MS is assigned three management
  connections in each direction.  These three connections reflect the
  three different QoS requirements used by different management levels.
  The first of these is the basic connection, which is used for the
  transfer of short, time-critical MAC management messages and radio
  link control (RLC) messages.  The primary management connection is
  used to transfer longer, more delay-tolerant messages such as those
  used for authentication and connection setup.  The secondary
  management connection is used for the transfer of standards-based





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RFC 5181            IPv6 over IEEE 802.16 Scenarios             May 2008


  management messages such as Dynamic Host Configuration Protocol
  (DHCP), Trivial File Transfer Protocol (TFTP), and Simple Network
  Management Protocol (SNMP).

  IPv6-based IEEE 802.16 networks can be managed by IPv4 or IPv6 when
  network elements are implemented dual stack.  SNMP messages can be
  carried by either IPv4 or IPv6.

3.  Security Considerations

  This document provides a detailed description of various IPv6
  deployment scenarios and link models for IEEE 802.16-based networks,
  and as such does not introduce any new security threats.  No matter
  what the scenario applied is, the networks should employ the same
  link layer security mechanisms defined in [IEEE802.16e] and IPv6
  transition security considerations defined in [RFC4942].  However, as
  already described in [RFC4968], a shared prefix model-based mobile
  access deployment scenario may have security implications for
  protocols that are designed to work within the scope.  This is the
  concern for a shared prefix link model wherein private resources
  cannot be put onto a public 802.16-based network.  This may restrict
  the usage of a shared prefix model to enterprise environments.

4.   Acknowledgements

  This work extends v6ops work on [RFC4779].  We thank all the authors
  of the document.  Special thanks are due to Maximilian Riegel, Jonne
  Soininen, Brian E. Carpenter, Jim Bound, David Johnston, Basavaraj
  Patil, Byoung-Jo Kim, Eric Klein, Bruno Sousa, Jung-Mo Moon, Sangjin
  Jeong, and Jinhyeock Choi for extensive review of this document.  We
  acknowledge Dominik Kaspar for proofreading the document.

5.  References

5.1.  Normative References

  [RFC4861]           Narten, T., Nordmark, E., Simpson, W., and H.
                      Soliman, "Neighbor Discovery for IP version 6
                      (IPv6)", RFC 4861, September 2007.

  [RFC4862]           Thomson, S., Narten, T., and T. Jinmei, "IPv6
                      Stateless Address Autoconfiguration", RFC 4862,
                      September 2007.








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5.2.  Informative References

  [IEEE802.16]        "IEEE 802.16-2004, IEEE Standard for Local and
                      Metropolitan Area Networks, Part 16: Air
                      Interface for Fixed Broadband Wireless Access
                      Systems", October 2004.

  [IEEE802.16e]       "IEEE Standard for Local and Metropolitan Area
                      Networks Part 16:  Air Interface for Fixed and
                      Mobile Broadband Wireless Access Systems
                      Amendment 2:  Physical and Medium Access Control
                      Layers for Combined Fixed and Mobile Operation in
                      Licensed Bands and Corrigendum 1", February 2006.

  [IEEE802.16f]       "Amendment to IEEE Standard for Local and
                      Metropolitan Area Networks,  Part 16: Air
                      Interface for Fixed Broadband Wireless Access
                      Systems - Management Information Base",
                      December 2005.

  [IEEE802.16g]       "Draft Amendment to IEEE Standard for Local and
                      Metropolitan Area Networks,  Part 16: Air
                      Interface for Fixed Broadband Wireless Access
                      Systems - Management Plane Procedures and
                      Services", January 2007.

  [IP-ETHERNET]       Jeon, H., Riegel, M., and S. Jeong, "Transmission
                      of IP over Ethernet over IEEE 802.16 Networks",
                      Work in Progress, April 2008.

  [MIPSHOP-FH80216E]  Jang, H., Jee, J., Han, Y., Park, S., and J. Cha,
                      "Mobile IPv6 Fast Handovers over IEEE 802.16e
                      Networks", Work in Progress, March 2008.

  [RFC2464]           Crawford, M., "Transmission of IPv6 Packets over
                      Ethernet Networks", RFC 2464, December 1998.

  [RFC2740]           Coltun, R., Ferguson, D., and J. Moy, "OSPF for
                      IPv6", RFC 2740, December 1999.

  [RFC3314]           Wasserman, M., "Recommendations for IPv6 in Third
                      Generation Partnership Project (3GPP) Standards",
                      RFC 3314, September 2002.

  [RFC3775]           Johnson, D., Perkins, C., and J. Arkko, "Mobility
                      Support in IPv6", RFC 3775, June 2004.





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RFC 5181            IPv6 over IEEE 802.16 Scenarios             May 2008


  [RFC4068]           Koodli, R., "Fast Handovers for Mobile IPv6",
                      RFC 4068, July 2005.

  [RFC4541]           Christensen, M., Kimball, K., and F. Solensky,
                      "Considerations for Internet Group Management
                      Protocol (IGMP) and Multicast Listener Discovery
                      (MLD) Snooping Switches", RFC 4541, May 2006.

  [RFC4605]           Fenner, B., He, H., Haberman, B., and H. Sandick,
                      "Internet Group Management Protocol (IGMP) /
                      Multicast Listener Discovery (MLD)-Based
                      Multicast Forwarding ("IGMP/MLD Proxying")",
                      RFC 4605, August 2006.

  [RFC4779]           Asadullah, S., Ahmed, A., Popoviciu, C., Savola,
                      P., and J. Palet, "ISP IPv6 Deployment Scenarios
                      in Broadband Access Networks", RFC 4779,
                      January 2007.

  [RFC4840]           Aboba, B., Davies, E., and D. Thaler, "Multiple
                      Encapsulation Methods Considered Harmful",
                      RFC 4840, April 2007.

  [RFC4942]           Davies, E., Krishnan, S., and P. Savola, "IPv6
                      Transition/Co-existence Security Considerations",
                      RFC 4942, September 2007.

  [RFC4968]           Madanapalli, S., "Analysis of IPv6 Link Models
                      for 802.16 Based Networks", RFC 4968,
                      August 2007.

  [RFC5121]           Patil, B., Xia, F., Sarikaya, B., Choi, JH., and
                      S. Madanapalli, "Transmission of IPv6 via the
                      IPv6 Convergence Sublayer over IEEE 802.16
                      Networks", RFC 5121, February 2008.

  [RFC5154]           Jee, J., Madanapalli, S., and J. Mandin, "IP over
                      IEEE 802.16 Problem Statement and Goals",
                      RFC 5154, April 2008.












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Authors' Addresses

  Myung-Ki Shin
  ETRI
  161 Gajeong-dong Yuseng-gu
  Daejeon, 305-350
  Korea

  Phone: +82 42 860 4847
  EMail: [email protected]


  Youn-Hee Han
  KUT
  Gajeon-Ri 307 Byeongcheon-Myeon
  Cheonan-Si Chungnam Province, 330-708
  Korea

  EMail: [email protected]


  Sang-Eon Kim
  KT
  17 Woomyeon-dong, Seocho-gu
  Seoul, 137-791
  Korea

  EMail: [email protected]


  Domagoj Premec
  Siemens Mobile
  Heinzelova 70a
  10010 Zagreb
  Croatia

  EMail: [email protected]














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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.

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  The IETF takes no position regarding the validity or scope of any
  Intellectual Property Rights or other rights that might be claimed to
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  Copies of IPR disclosures made to the IETF Secretariat and any
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