Network Working Group M-K. Shin Internet-Draft ETRI Intended status: Informational Y-H. Han Expires:
April 4,July 20, 2007 KUT S-E. Kim KT D. Premec Siemens Mobile October 1, 2006January 16, 2007 IPv6 Deployment Scenarios in 802.16(e) Networks draft-ietf-v6ops-802-16-deployment-scenarios-01draft-ietf-v6ops-802-16-deployment-scenarios-02 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 on April 4,July 20, 2007. Copyright Notice Copyright (C) The Internet Society (2006).(2007). Abstract This document provides 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 main components of IPv6 IEEE 802.16 access network and its differences from IPv4 IEEE 802.16 networks and how IPv6 is deployed and integrated in each of the IEEE 802.16 technologies using tunneling mechanisms and native IPv6. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Wireless Broadband Access Network Technologies -Deploying IPv6 in IEEE 802.16 . . . . . . . . . . . . . . . .Networks . . . . . . . . . . . . 4 2.1. Elements of IEEE 802.16 Networks . . . . . . . . . . . . . 4 2.2. DeployingScenarios and IPv6 in IEEE 802.16 NetworksDeployment . . . . . . . . . . . . . . 5 2.2.1. Mobile Access Deployment Scenarios . . . . . . . . . . 65 2.2.2. Fixed/Nomadic Deployment Scenarios . . . . . . . . . . 109 2.3. IPv6 Multicast . . . . . . . . . . . . . . . . . . . . . . 1312 2.4. IPv6 QoS . . . . . . . . . . . . . . . . . . . . . . . . . 1413 2.5. IPv6 Security . . . . . . . . . . . . . . . . . . . . . . 1413 2.6. IPv6 Network Management . . . . . . . . . . . . . . . . . 1513 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 1615 4. Security Considerations . . . . . . . . . . . . . . . . . . . 1716 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 1817 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 1918 6.1. Normative References . . . . . . . . . . . . . . . . . . . 1918 6.2. Informative References . . . . . . . . . . . . . . . . . . 1918 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 2120 Intellectual Property and Copyright Statements . . . . . . . . . . 2221 1. Introduction Recently, broadband wireless access network is emerging for wireless communication for user requirements such as high quality data/voice service, fast mobility, wide coverage, etc. The IEEE 802.16 Working Group develops standards and recommended practices to support the development and deployment of broadband wireless metropolitan area networks. Whereas the [IEEE802.16] standard addresses fixed wireless applications only, the [IEEE802.16e] standard serves the needs of fixed, nomadic, and fully mobile networks. It adds mobility support to the original standard so that mobile subscriber stations can move during services. The standardization of IEEE 802.16e is completed, which plans to support mobility up to speeds of 70~80 mile/h that will enable the subscribers to carry mobile devices such as PDAs, phones, or laptops. IEEE 802.16e is one of the most promising access technologies which would be applied to the IP-based broadband mobile communication.As the deployment of wireless broadbandIEEE 802.16(e) access network progresses, users will be connected to IPv6 networks. While the IEEE 802.16 defines the encapsulation of an IPv4/IPv6 datagram in an IEEE 802.16 MAC payload, a complete description of IPv4/IPv6 operation and deployment is not present. In this document, we will discuss main components of IPv6 IEEE 802.16 access network and its differences from IPv4 IEEE 802.16 networks and how IPv6 is deployed and integrated in each of the IEEE 802.16 technologies using tunneling mechanisms and native IPv6. This document extends works of [I-D.ietf-v6ops-bb-deployment- scenarios] and follows the structure and common terminology of the document. 2. Wireless Broadband Access Network Technologies - IEEE 802.16 This section describes the infrastructure that is based on IEEE 802.16 networks providing wireless broadband services to the customer. It also describes a way to deployDeploying IPv6 overin IEEE 802.16 networks.Networks 2.1. Elements of IEEE 802.16 Networks The IEEE 802.11 access network (WLAN) has driven the revolution of wireless communication. However, the more people use it the more its limitations such as short range and lack of mobility support arose. Compared with such IEEE 802.11 network, IEEE 802.16 supports enhanced features such as wider coverage and mobility. So it is expected that IEEE 802.16 network could be the next step of IEEE 802.11 network. Themechanism of transporting IP traffic over IEEE 802.16 networks is outlined in [IEEE802.16], but[IEEE802.16]. [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 being discussed now.now in 16ng WG. Here are some of the key elements of an IEEE 802.16 network: o MS: Mobile Station. A stationnetwork. The terminologies in the mobile service intendedthis document "SS(MS)", "BS", and "AR" are to be used whileinterpreted as described in motion[I-D.ietf-16ng-ps-goals]. o Subscriber Station (SS): An end-user equipment that provides connectivity to the 802.16 networks. It can be either fixed/ nomadic or during halts at unspecified points. Amobile stationequipment. In mobile environment, SS represents the Mobile Subscriber Station (MS) is always a subscriber station (SS) which must provide mobility function.introduced in IEEE 802.16e specification. o BS:Base Station.Station (BS): A generalized equipment setsets providing managementconnectivity, management, and control of MS connections. There is a unidirectional mappingbetween BS and MS medium access control (MAC) peers forthe purpose of transporting a service flow's traffic. A connection is identified by a connection identifier (CID). All traffic is carried onsubscriber station and the connection. Sometimes there can be alternative IEEE802.16 network deployment where a BS is integrated with an access router, composing one box in view of implementation.networks. o AR:Access Router. A generalized equipment set providing IP connectivity between BS and IP based network.Router (AR): An ARentity that performs first hopan IP routing function to all MS.provide IP connectivity for subscriber station (SS or MS). Figure 1 illustrates the key elements of IEEE 802.16(e) networks.typical mobile 802.16 deployments. Customer | Access Provider | Service Provider Premise | | (Backend Network) +-----+ +----+ +----+ +--------+ | MSsSSs |--(802.16)--| BS |-----| | | Edge | ISP +-----+ +----+ | AR |---| Router |==>Network +--| | | (ER) | | +----+ +--------+ +-----+ +----+ | | +------+ | MSsSSs |--(802.16)--| BS |--+ +--|AAA | +-----+ +----+ |Server| +------+ Figure 1: Key Elements of IEEE 802.16(e) Networks 2.2. DeployingScenarios and IPv6 in IEEE 802.16 NetworksDeployment [IEEE802.16] specifies two modes for sharing the wireless medium: point-to-multipoint (PMP) and mesh (optional). This document only focuses on PMP mode. Some of the factors that hinder deployment of native IPv6 core protocols are introduced by [I-D.jee-16ng-problem-statement]. The summary of them is as follows: 1. Lacking of Facility for IPv6 Native Multicasting IEEE 802.16 PMP mode is a connection oriented technology without bi- directional native multicast support. IPv6 neighbor discovery [RFC2461] supports various functions for the interaction between nodes attached on the same subnet, such as on-link determination and address resolution. It is designed with no dependence on a specific link layer technology, but requires that the link layer technology support native multicast. This lacking of facility for IPv6 native multicast results in inappropriateness to apply the standard neighbor discover protocol specially regarding, address resolution, router discovery, stateless auto-configuration and duplicated address detection. 2. Impact on IPv6 Subnet Model IEEE 802.16 is different from existing wireless access technologies such as IEEE 802.11 or 3G, and, while IEEE 802.16 defines the encapsulation of an IP datagram in an IEEE 802.16 MAC payload, a complete description of IPv6 operation is not present. IEEE 802.16 can rather benefit from IETF input and specification to support IPv6 operation. Especially, BS should look at the classifiers and decide where to send the packet, since IEEE 802.16 connection always ends at BS, while IPv6 connection terminates at a default router. This operation and limitation may be dependent on the given subnet model [I-D.madanapalli-16ng-subnet-model-analysis]. 3. Multiple Convergence Sublayers (CS) There are operational complexity problems of IP over 802.16 caused by the existence of multiple convergence sublayers [I-D.iab-link- encaps]. We should consider which type of Convergence Sublayer (CS) can be efficiently used on each subnet models and scenarios. IEEE 802.16 CS delivers and classifies various kinds of higher layer PDUs such as ATM, IPv4 packet and IPv6 packets over radio channel. For this purpose, IEEE 802.16 introduces the Connection Identifier (CID). Generally, CS performs the following functions in terms of IP packet transmission: 1) Receipt of protocol data units (PDUs) from the higher layer, 2) Performing classification and CID mapping of the PDUs, 3) Delivering the PDUs to the appropriate MAC SAP, 4) Receipt of PDUs from the peer MAC SAP, and 5) Forwarding the PDUs to the corresponding AR. The specification of IEEE 802.16 defines several CSs for carrying IP packets, but does not provide a detailed description of how to carry them. The several CSs are generally classified into two types of CS: IPv6 CS and Ethernet CS. In addition, due to the problems caused by the existence of multiple convergence sublayers [I-D.iab-link-encaps], the mobile access scenarios need solutions about how roaming will work when forced to move from one CS to another. Note that, at this phase this issue is the out of scope of this draft. It should be also discussed in 16ng WG.deployment of native IPv6 core protocols are already introduced by [I-D.ietf-16ng-ps-goals]. There are two different deployment scenarios: fixed and mobile access.access deployment scenarios. A fixed access scenario substitudes for existing wired-based access technologies such as digital subscriber line (xDSL) and cable network. This fixed access scenario can provide nomadic access within the radio coverages, which is called Hot-zone model. A mobile access scenario is for new paradigm for voice, data and video over mobile network. This scenario can provide high speed data rate equalivent to wire-based Internet as well as mobility function equivalent to cellular system. The mobile access scenario can be classified into two different IPv6 sunbetlink models: shared IPv6 prefix link model and point-to-point link model. 2.2.1. Mobile Access Deployment Scenarios Unlike IEEE 802.11, IEEE 802.16 BS can offer mobility function as well as fixed communication. [IEEE802.16e] has been standardized to provide mobility features on IEEE 802.16 environments. This use case will be implemented only with the licensed spectrum.IEEE 802.16 BS might be deployed with a proprietary backend managed by an operator. All original IPv6 functionalities [RFC2461], [RFC2462] will not survive.Some architectural characteristics of IEEE 802.16 networks may affect the detailed operations of NDP [RFC2461].[RFC2461], [RFC2462]. There are two possible IPv6 subnetlink models for mobile access deployment scenarios: shared IPv6 prefix link model and point-to- pointpoint-to-point link model [I-D.madanapalli-16ng-subnet-model-analysis].[I-D.ietf-16ng-ipv6-link-model-analysis]. There is alwayes a default access router in the scenarios. There 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 IEEE 802.16 mobile access network deployment where a subnet consists of only single interface of AR and multiple MSs. Therefore, all MSs and corresponding interface of AR share the same IPv6 prefix as shown in Figure 2. IPv6 prefix will be different from the interface of AR. +-----+ | MS1 |<-(16)-+ +-----+ | +-----+ | +-----+ +-----+ +--------+ | MS2 |<-(16)-+----| BS1 |--+->| AR |----| Edge | ISP +-----+ +-----+ | +-----+ | Router +==>Network | +--------+ +-----+ +-----+ | | MS3 |<-(16)-+----| BS2 |--+ +-----+ | +-----+ +-----+ | | MS4 |<-(16)-+ +-----+ Figure 2: Shared IPv6 Prefix Link Model 2. Point-to-Point Link Model This link model represents IEEE 802.16 mobile access network deployment where a subnet consists of only 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 unique set of prefixes by the AR. The point-to- point link model follows the recommendations of [RFC3314]. +-----+ | MS1 |<-(16)---------+ +-----+ | +-----+ +-----+ +-----+ +--------+ | MS2 |<-(16)------| BS1 |--+->| AR |----| Edge | ISP +-----+ +-----+ | +-----+ | Router +==>Network | +--------+ +-----+ +-----+ | | MS3 |<-(16)------| BS2 |--+ +-----+ +-----+ +-----+ | | MS4 |<-(16)---------+ +-----+ Figure 3: Point-to-Point Link Model 22.214.171.124. IPv6 Related Infrastructure Changes IPv6 will be deployed in this scenario by upgrading the following devices to dual-stack: MS, BS,AR and ER. In this scenario, IEEE 802.16 BSs have only MAC and PHY layers without router function and operates as a bridge. The BS does not need to support IPv6. However, if IPv4 stack is loaded to them for management and configuration purpose, it is expected that BS should be upgraded by implementing IPv6 stack, too. 126.96.36.199. Addressing 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. IPv6 MS can get the IPv6 address from an access router using stateless auto-configuration. In this case, router discovery and DAD operation should be properly operated over IEEE 802.16 link. 2. IPv6 MS can use 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 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 same AR can be on same IPv6 link. As for the prefix assignment, in case of shared IPv6 prefix link model, one or more IPv6 prefixes are assigned to the link and hence shared by all the nodes that are attached to the link. In point-to- point link model, the AR assigns a unique prefix or set of unique prefixes for each MS. Prefix delegation can be required if networks can exist behind MS. 188.8.131.52. IPv6 Transport In a subnet, there are always two underlying links: one is the IEEE 802.16 wireless link between MS and BS, and the other is a wired link between BS and AR. The IPv6 packet should be classified by IPv6 source/destination addresses, etc. BS generates the flow based on the classification. It also decides where to send the packet or just forward the packet to the ACR, since IEEE 802.16 connection always ends at BS while IPv6 connection terminates at the AR. This operation may be dependent on IPv6 subnet models. If stateless auto-configuration is used to get an IPv6 address, router discovery and DAD operation should be properly operated over IEEE 802.16 link. In case of shared IPv6 prefix link model, the DAD [RFC2461] does not adapt well to the 802.16 air interface as there is no native multicast support and when supported consumes air bandwidth as well as it would have adverse effect on MSs that were in the dormant mode.support. An optimization, called Relay DAD, may be required to perform DAD. However, in case of point-to-point link model, DAD is easy since each connection to a MN is treated as a unique IPv6 link. Note that in this scenario IPv6 CS may be more appropriate than Ethernet CS to transport IPv6 packets, since there are some overhead of Ethernet CS (e.g., Ethernet header) under mobile access environments .environments. However PHS (Packet Header Compression), if deployed, mitigates much of this overhead. Simple or complex network equipments may constitute the underlying wired network between the AR and the ER. If the IP aware equipments between the AR and the ER do 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 option might be more scalable and provide required service performance. Tunneling mechanisms should only be used when native IPv6 deployment is not an option. This can be equally applied to other scenario below (Section 2.2.2). 184.108.40.206. Routing In general, the MS is configured with a default route that points to the the AR. Therefore, no routing protocols are needed on the MS. The MS just sends to the AR by default route. The AR can configure multiple link to ER for network reliability. The AR should support IPv6 routing protocol such as OSPFv3 [RFC2740] or IS-IS for IPv6 when connected to the ER with multiple links. The ER runs the 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. 220.127.116.11. Mobility As for mobility management, the movement between BSs is handled by Mobile IPv6 [RFC3775], if it requires a subnet change. Also, in certain cases (e.g., fast handover [I-D.ietf-mipshop-fmipv6- rfc4068bis]) the link mobility information must be available for facilitating layer 3 handoff procedure. Mobile IPv6 defines that movement detection uses Neighbor Unreachability Detection to detect when the default router is no longer bi-directionally 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 IEEE 802.16 MAC provides the reachability by its Ranging procedure and the movement detection by the Handoff procedure. IEEE 802.16 defines L2 triggers whether refresh of an IP address is required during the handoff. Though a handoff has occurred, an additional router discovery procedure is not required in case of intra-subnet handoff. Also, faster handoff may be occurred by the L2 trigger in case of inter-subnet handoff. Also, IEEE 802.16g which is under-developed defines L2 triggers for link status such as link-up, link-down, handoff-start. These L2 triggers may make Mobile IPv6 procedure more efficient and faster. In addition, Mobile IPv6 Fast Handover assumes the support from link- layer technology, but the particular link-layer information being available, as well as the timing of its availability (before, during or after a handover has occurred), differs according to the particular link-layer technology in use. This issue is also being discussed in [I-D.ietf-mipshop-fh80216e]. In addition, due to the problems caused by the existence of multiple convergence sublayers [I-D.iab-link-encaps], the mobile access scenarios need solutions about how roaming will work when forced to move from one CS to another. Note that, at this phase this issue is the out of scope of this draft. It should be also discussed in 16ng WG. 2.2.2. Fixed/Nomadic Deployment Scenarios The IEEE 802.16 access networks can provide plain Ethernet connectivity end-to-end. 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 service. A company can use IEEE 802.16 to build up mobile office. Wireless Internet spreading through a campus or a cafe can be also implemented with it. The distinct point of this use case is that it can use unlicensed (2.4 & 5 GHz) band as well as licensed (2.6 & 3.5GHz) band. By using the unlicensed band, an IEEE 802.16 BS might be used just as a wireless switch/hub which a user purchases to build a private wireless network in his/her home or laboratory. Under fixed access model, the IEEE 802.16 BS will be deployed using an IP backbone rather than a proprietary backend like cellular systems. Thus, many IPv6 functionalities such as [RFC2461], [RFC2462] will be preserved when adopting IPv6 to IEEE 802.16 devices. This scenario also represents IEEE 802.16 network deployment where a subnet consists of multiple MSs and multiple interface of the multiple BSs. Multiple access routers can exist. There exist multiple hosts behind an SS (networks behind an MSSS may exist). When 802.16 access networks are widely deployed like WLAN, this case should be also considered. Hot-zone deployment model falls within this case. +-----+ +-----+ +-----+ ISP 1 | SS1 |<-(16)+ +->| AR1 |----| ER1 |===>Network +-----+ | | +-----+ +-----+ +-----+ | +-----+ | | SS2 |<-(16)+-----| BS1 |--| +-----+ +-----+ | +-----+ +-----+ ISP 2 +->| AR2 |----| ER2 |===>Network +-----+ +-----+ +-----+ | +-----+ +-----+ |Hosts|<-->|SS/GW|<-(16)------| BS2 |--+ +-----+ +-----+ +-----+ This network behind MSSS may exist Figure 4: Fixed/Nomadic Deployment Scenario While Figure 34 illustrates a generic deployment scenario, the following Figure 45 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 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 BRAS (Broadband Remote Access Server). 18.104.22.168. IPv6 Related Infrastructure Changes IPv6 will be deployed in this scenario by upgrading the following devices to dual-stack: MS, BS,AR and ER. In this scenario, IEEE 802.16 BSs have only MAC and PHY layers without router function and operates as a bridge. The BS does not need to support IPv6. However, if IPv4 stack is loaded to them for management and configuration purpose, it is expected that BS should be upgraded by implementing IPv6 stack, too. The BRAS in Figure 45 is providing the functionality of the AR. The Ethernet bridge is necessary for protecting the BRAS from 802.16 link layer peculiarities. The Ethernet bridge relays all traffic received through BS to its network side port(s) connected to BRAS. Any traffic received from BRAS is relayed to appropriate BS. Since 802.16 MAC layer has no native support for multicast (and broadcast) in the uplink direction, the Ethernet bridge will emulate Ethernet levelimplement 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 22.214.171.124). 126.96.36.199. Addressing One or more IPv6 prefixes can be shared to all the attached MSs. Prefix delegation can be required sinceif networks can exist behind SS. 188.8.131.52. IPv6 Transport Note that in this scenario Ethernet CS may be more appropriate than IPv6 CS to transport IPv6 packets, since the scenario need to support plain Ethernet connectivity end-to-end. However, the IPv6 CS can also be supported. EveryThe MS and theBS haswill consider the Ethernet type MAC address. Ifconnections between the MS is usingpeer IP CS, then the BS needs to take care of the Ethernet header. In the upstream direction,CSs at the MS and BS will needto generate an appropriate Ethernet header and prepend itform a point to the IP datagram.point link. In the downstream direction, the BS will use the destination address from the Ethernet header to identify the MS and then it will strip theEthernet header before relaying the IP datagram over the 802.16 MAC connection.CS case, an Ethernet bridge may provide implementation of authoritative address cache and Relay DAD. Authoritative address cache is a mapping between the IPv6 address and the MAC addresses of all attached MSs. The bridge builds its authoritative address cache by parsing the IPv6 Neighbor Discovery messages used during address configuration (DAD). Relay DAD means that the Neighbor Solicitation message used in DAD process will be relayed only to the MS which already has configured the solicited address as its own address (if such MS exist at all). 184.108.40.206. Routing In this scenario, IPv6 multi-homing considerations exist. For example, if there exist two routers to support MSs, 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. 220.127.116.11. Mobility No mobility functions are supported in fixed access scenario. However, mobility can support in the radio coverage without any mobility protocol like WLAN technology. Therefore, a user can access Internet nomadically in the coverage. 2.3. IPv6 Multicast In IEEE 802.16 air link, downlink connections can be shared among multiple MSs, enabling multicast channels with multiple MSs receiving the same information from the BS. MBS may be used to efficiently implement multicast. However, it is not clear how to do this, as currently CID is assigned by BS, but in MBS it should be done at an AR and it's network scope. For MBS how this mapping will happen is not clear, so MBS discussions have been postponed in WiMax for now. Note that it should be intensively researched later, since MBS will be one of the killer services in IEEE 802.16 networks. In order to support multicast services in IEEE 802.16, Multicast Listener Discovery (MLD) [RFC2710] must be supported between the MS and AR. Also, the inter-working with IP multicast protocols and Multicast and Broadcast Service (MBS) should be considered. MBS defines Multicast and Broadcast Services, but actually, MBS seems to be a broadcast service, not multicasting. MBS adheres to broadcast services, while traditional IP multicast schemes define multicast routing using a shared tree or source-specific tree to deliver packets efficiently. In IEEE 802.16 networks, two types of access to MBS may be supported: single-BS access and multi-BS access. Therefore, these two types of services may be roughly mapped into Source-Specific Multicast. 2.4. IPv6 QoS In IEEE 802.16 networks, a connection is unidirectional and has a QoS specification. The QoS has different semantics with IP QoS (e.g., diffserv). Mapping CID to Service Flow IDentifier (SFID) defines QoS parameters of the service flow associated with that connection. In order to interwork with IP QoS, IP QoS (e.g., diffserv, or flow label for IPv6) mapping to IEEE 802.16 link specifics should be provided. 2.5. IPv6 Security When initiating the connection, an MS is authenticated by the AAA server located at its service provider network. All the parameters related to authentication (username, password and etc.) are forwarded by the BS to the AAA server. The AAA server authenticates the MSs and once authenticated. When an MS is once authenticated and associated successfully with BS, IPv6 address will be acquired by the MS with stateless autoconfiguration or DHCPv6. Note the initiation and authentication process is the same as used in IPv4. IPsec is a fundamental part of IPv6. Unlike IPv4, IPsec for IPv6 may be used within the global end-to-end architecture. But, we don't have PKIs across organizations and IPsec isn't integrated with IEEE 802.16 network mobility management. IEEE 802.16 network threats may be different from IPv6 and IPv6 transition threat models [I-D.ietf-v6ops-security-overview]. It should be also discussed. 2.6. IPv6 Network Management 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 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 network can be managed by IPv4 or IPv6 when network elements are implemented dual stak. For example, network management system (NMS) can send SNMP message by IPv4 with IPv6 related object identifier. Also, an NMS can use IPv6 for SNMP request and response including IPv4 related OID. 3. IANA Considerations This document requests no action by IANA. 4. Security Considerations Please refer to Section 2.5 "IPv6 Security" technology sections for details. 5. Acknowledgements This work extends v6ops works on [I-D.ietf-v6ops-bb-deployment- scenarios]. 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 and Jung-Mo Moon for extensive review of this document. 6. References 6.1. Normative References [RFC2461] Narten, T., Nordmark, E., and W. Simpson, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998. [RFC2462] Thomson, S. and T. Narten, "IPv6 Stateless Address Autoconfiguration", RFC 2462, December 1998. [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast Listener Discovery (MLD) for IPv6", RFC 2710, October 1999. [RFC2740] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", RFC 2740, December 1999. 6.2. Informative References [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. [I-D.jee-16ng-problem-statement][I-D.ietf-16ng-ps-goals] Jee, J., "16ng"IP over 802.16 Problem Statement", draft-jee-16ng-problem-statement-02Statement and Goals", draft-ietf-16ng-ps-goals-00 (work in progress), October 2005. [I-D.madanapalli-16ng-subnet-model-analysis]2006. [I-D.ietf-16ng-ipv6-link-model-analysis] Madanapalli, S., "Analysis of IPv6 Link Models for 802.16 based Networks", draft-madanapalli-16ng-subnet-model-analysis-01draft-ietf-16ng-ipv6-link-model-analysis-02 (work in progress), September 2006.January 2007. [I-D.ietf-mipshop-fmipv6-rfc4068bis] Koodli, R., "Fast Handovers for Mobile IPv6", draft-ietf-mipshop-fmipv6-rfc4068bis-00 (work in progress), May 2006. [I-D.ietf-mipshop-fh80216e] Jang, H., "Mobile IPv6 Fast Handovers over IEEE 802.16e Networks", draft-ietf-mipshop-fh80216e-00draft-ietf-mipshop-fh80216e-01 (work in progress), April 2006.January 2007. [I-D.ietf-v6ops-security-overview] Davies, E., "IPv6 Transition/Co-existence Security Considerations", draft-ietf-v6ops-security-overview-05draft-ietf-v6ops-security-overview-06 (work in progress), SeptemberOctober 2006. [I-D.ietf-v6ops-bb-deployment-scenarios] Asadullah, S., "ISP IPv6 Deployment Scenarios in Broadband Access Networks", draft-ietf-v6ops-bb-deployment-scenarios-05 (work in progress), June 2006. [I-D.iab-link-encaps] Aboba, B., "Multiple Encapsulation Methods Considered Harmful", draft-iab-link-encaps-02draft-iab-link-encaps-05 (work in progress), AugustOctober 2006. [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 Std. 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. Authors' Addresses Myung-Ki Shin ETRI 161 Gajeong-dong Yuseng-gu Daejeon, 305-350 Korea Phone: +82 42 860 4847 Email: firstname.lastname@example.org Youn-Hee Han KUT Gajeon-Ri 307 Byeongcheon-Myeon Cheonan-Si Chungnam Province, 330-708 Korea Email: email@example.com Sang-Eon Kim KT 17 Woomyeon-dong, Seocho-gu Seoul, 137-791 Korea Email: firstname.lastname@example.org Domagoj Premec Siemens Mobile Heinzelova 70a 10010 Zagreb Croatia Email: email@example.com Full Copyright Statement Copyright (C) The Internet Society (2006).(2007). 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. 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