--- 1/draft-ietf-v6ops-mobile-device-profile-17.txt 2015-02-18 23:14:53.456566282 -0800 +++ 2/draft-ietf-v6ops-mobile-device-profile-18.txt 2015-02-18 23:14:53.500567362 -0800 @@ -1,112 +1,119 @@ V6OPS Working Group D. Binet Internet-Draft M. Boucadair Intended status: Informational France Telecom -Expires: August 16, 2015 A. Vizdal +Expires: August 22, 2015 A. Vizdal Deutsche Telekom AG G. Chen China Mobile N. Heatley EE R. Chandler eircom | meteor - February 12, 2015 + D. Michaud + Rogers Communications + D. Lopez + Telefonica I+D + February 18, 2015 An Internet Protocol Version 6 (IPv6) Profile for 3GPP Mobile Devices - draft-ietf-v6ops-mobile-device-profile-17 + draft-ietf-v6ops-mobile-device-profile-18 Abstract This document defines a profile that is a superset of that of the connection to IPv6 cellular networks defined in the IPv6 for Third Generation Partnership Project (3GPP) Cellular Hosts document. This document defines an IPv6 profile that a number of operators recommend in order to connect 3GPP mobile devices to an IPv6-only or dual-stack - wireless network (including 3GPP cellular network and IEEE 802.11 - network) with a special focus on IPv4 service continuity features. + wireless network (including 3GPP cellular network) with a special + focus on IPv4 service continuity features. Both hosts and devices with capability to share their WAN (Wide Area Network) connectivity are in scope. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." - - This Internet-Draft will expire on August 16, 2015. + This Internet-Draft will expire on August 22, 2015. Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 + 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 2. Connectivity Recommendations . . . . . . . . . . . . . . . . 5 - 2.1. WLAN Connectivity Recommendations . . . . . . . . . . . . 8 - 3. Advanced Recommendations . . . . . . . . . . . . . . . . . . 8 - 4. Recommendations for Cellular Devices with LAN Capabilities . 10 - 5. APIs & Applications Recommendations . . . . . . . . . . . . . 12 - 6. Security Considerations . . . . . . . . . . . . . . . . . . . 13 - 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 - 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 - 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 - 9.1. Normative References . . . . . . . . . . . . . . . . . . 14 - 9.2. Informative References . . . . . . . . . . . . . . . . . 15 + 2. Connectivity Recommendations . . . . . . . . . . . . . . . . 6 + 3. Recommendations for Cellular Devices with LAN Capabilities . 9 + 4. Advanced Recommendations . . . . . . . . . . . . . . . . . . 11 + 5. Security Considerations . . . . . . . . . . . . . . . . . . . 13 + 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 + 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 14 + 8.1. Normative References . . . . . . . . . . . . . . . . . . 14 + 8.2. Informative References . . . . . . . . . . . . . . . . . 16 1. Introduction IPv6 deployment in 3GPP mobile networks is the only perennial solution to the exhaustion of IPv4 addresses in those networks. Several mobile operators have already deployed IPv6 [RFC2460] or are in the pre-deployment phase. One of the major hurdles as perceived by some mobile operators is the availability of non-broken IPv6 implementation in mobile devices (e.g., Section 3.3 of [OECD]). [RFC7066] lists a set of features to be supported by cellular hosts to connect to 3GPP mobile networks. In the light of recent IPv6 production deployments, additional features to facilitate IPv6-only - deployments while accessing IPv4-only service are to be considered. + deployments while accessing IPv4-only services are to be considered. + This document fills this void. Concretely, this document lists means + to ensure IPv4 service continuity over an IPv6-only connectivity + given the adoption rate of this model by mobile operators. Those + operators require that no service degradation is experienced by + customers serviced with an IPv6-only model compared to the level of + service of customers with legacy IPv4-only devices. This document defines an IPv6 profile for mobile devices listing specifications produced by various Standards Developing Organizations - (in particular 3GPP and IETF). The objectives of this effort are: + (including 3GPP, IETF, and GSMA). The objectives of this effort are: 1. List in one single document a comprehensive list of IPv6 features for a mobile device, including both IPv6-only and dual-stack mobile deployment contexts. These features cover various network - types such as GPRS (General Packet Radio Service), EPC (Evolved - Packet Core) or IEEE 802.11 network. + types such as GPRS (General Packet Radio Service) or EPC (Evolved + Packet Core). 2. Help Operators with the detailed device requirement list preparation (to be exchanged with device suppliers). This is also a contribution to harmonize Operators' requirements towards device vendors. 3. Vendors to be aware of a set of features to allow for IPv6 connectivity and IPv4 service continuity (over an IPv6-only transport). @@ -114,36 +121,49 @@ information on the 3GPP releases detail, the reader may refer to Section 6.2 of [RFC6459]. Some of the features listed in this profile document require to activate dedicated functions at the network side. It is out of scope of this document to list these network-side functions. A detailed overview of IPv6 support in 3GPP architectures is provided in [RFC6459]. + This document is organized as follows: + + o Section 2 lists generic recommendations including functionalities + to provide IPv4 service continuity over an IPv6-only connectivity. + + o Section 3 enumerates a set of recommendations for cellular devices + with LAN capabilities (e.g., CPE, dongles with tethering + features). + + o Section 4 identifies a set of advanced recommendations to fulfill + requirements of critical services such as VoLTE (Voice over LTE). + 1.1. Terminology This document makes use of the terms defined in [RFC6459]. In addition, the following terms are used: o "3GPP cellular host" (or cellular host for short) denotes a 3GPP device which can be connected to 3GPP mobile networks or IEEE 802.11 networks. o "3GPP cellular device" (or cellular device for short) refers to a cellular host which supports the capability to share its WAN (Wide Area Network) connectivity. - o "Cellular host" and "mobile host" are used interchangeably. - - o "Cellular device" and "mobile device" are used interchangeably. + o "IPv4 service continuity" denotes the features used to provide + access to IPv4-only services to customers serviced with an + IPv6-only connectivity. A typical example of IPv4 service + continuity technique is NAT64 [RFC6146]. PREFIX64 denotes an IPv6 prefix used to build IPv4-converted IPv6 addresses [RFC6052]. 1.2. Scope A 3GPP mobile network can be used to connect various user equipments such as a mobile telephone, a CPE (Customer Premises Equipment) or a machine-to-machine (M2M) device. Because of this diversity of terminals, it is necessary to define a set of IPv6 functionalities @@ -152,24 +172,22 @@ This document is structured to provide the generic IPv6 recommendations which are valid for all nodes, whatever their function (e.g., host or CPE) or service (e.g., Session Initiation Protocol (SIP, [RFC3261])) capability. The document also contains sections covering specific functionalities for devices providing some LAN functions (e.g., mobile CPE or broadband dongles). The recommendations listed below are valid for both 3GPP GPRS and 3GPP EPS (Evolved Packet System) access. For EPS, PDN-Connection - term is used instead of PDP-Context. - - This document identifies also some WLAN-related IPv6 recommendations. - Other non-3GPP accesses [TS.23402] are out of scope of this document. + term is used instead of PDP-Context. Other non-3GPP accesses + [TS.23402] are out of scope of this document. This profile is a superset of that of the IPv6 profile for 3GPP Cellular Hosts [RFC7066], which is in turn a superset of IPv6 Node Requirements [RFC6434]. It targets cellular nodes, including GPRS, EPC (Evolved Packet Core) and IEEE 802.11 networks, that require features to ensure IPv4 service delivery over an IPv6-only transport in addition to the base IPv6 service. Moreover, this profile covers cellular CPEs that are used in various deployments to offer fixed- like services. Recommendations inspired from real deployment experiences (e.g., roaming) are included in this profile. Also, this @@ -190,61 +208,79 @@ Delegation compared to [RFC7066]. The main motivation is that cellular networks are more and more perceived as an alternative to fixed networks for home IP-based services delivery; especially with the advent of smartphones and 3GPP data dongles. There is a need for an efficient mechanism to assign shorter prefix than /64 to cellular hosts so that each LAN segment can get its own /64 prefix and multi- link subnet issues to be avoided. The support of this functionality in both cellular and fixed networks is key for fixed-mobile convergence. + The use of address family dependent APIs (Application Programming + Interfaces) or hard-coded IPv4 address literals may lead to broken + applications when IPv6 connectivity is in use. As such, means to + minimize broken applications when the cellular host is attached to an + IPv6-only network should be encouraged. Particularly, (1) name + resolution libraries (e.g., [RFC3596]) must support both IPv4 and + IPv6; (2) applications must be independent of the underlying IP + address family; (3) and applications relying upon Uniform Resource + Identifiers (URIs) must follow [RFC3986] and its updates. Note, some + IETF specifications (e.g., SIP [RFC3261]) contains broken IPv6 ABNF + and rules to compare URIs with embedded IPv6 addresses; fixes (e.g., + [RFC5954]) must be used instead. + + The recommendations included in each section are listed in a priority + order. + This document is not a standard, and conformance with it is not required in order to claim conformance with IETF standards for IPv6. - The support of the full set of features may not be required in some - deployment contexts. The authors believe that the support of a - subset of the features included in this protocol may lead to degraded - level of service in some deployment contexts. + Compliance with this profile does not require the support of all + enclosed items. Obviously, the support of the full set of features + may not be required in some deployment contexts. However, the + authors believe that not supporting relevant features included in + this profile (e.g., Customer Side Translator (CLAT, [RFC6877])) may + lead to a degraded level of service. 2. Connectivity Recommendations This section identifies the main connectivity recommendations to be - followed by a cellular host to attach to a network using IPv6. Both - dual-stack and IPv6-only deployment models are considered. IPv4 - service continuity features are listed in this section because these - are critical for Operators with an IPv6-only deployment model. + followed by a cellular host to attach to a network using IPv6 in + addition to what is defined in [RFC6434] and [RFC7066]. Both dual- + stack and IPv6-only deployment models are considered. IPv4 service + continuity features are listed in this section because these are + critical for Operators with an IPv6-only deployment model. C_REC#1: In order to allow each operator to select their own strategy regarding IPv6 introduction, the cellular host must support both IPv6 and IPv4v6 PDP-Contexts [TS.23060]. - Both IPv6 and IPv4v6 PDP-Contexts must be supported. IPv4, - IPv6 or IPv4v6 PDP-Context request acceptance depends on - the cellular network configuration. + IPv4, IPv6 or IPv4v6 PDP-Context request acceptance depends + on the cellular network configuration. C_REC#2: The cellular host must comply with the behavior defined in [TS.23060] [TS.23401] [TS.24008] for requesting a PDP- Context type. In particular, the cellular host must request by default an IPv6 PDP-Context if the cellular host - is IPv6-only and requesting an IPv4v6 PDP-Context if the + is IPv6-only and request an IPv4v6 PDP-Context if the cellular host is dual-stack or when the cellular host is not aware of connectivity types requested by devices connected to it (e.g., cellular host with LAN capabilities - as discussed in Section 4): + as discussed in Section 3): * If the requested IPv4v6 PDP-Context is not supported by the network, but IPv4 and IPv6 PDP types are allowed, then the cellular host will be configured with an IPv4 address or an IPv6 prefix by the network. It must initiate another PDP-Context activation in addition to the one already activated for a given APN (Access Point Name). - * If the requested PDP type and subscription data allows + * If the subscription data or network configuration allows only one IP address family (IPv4 or IPv6), the cellular host must not request a second PDP-Context to the same APN for the other IP address family. The text above focuses on the specification part which explains the behavior for requesting IPv6-related PDP- Context(s). Understanding this behavior is important to avoid having broken IPv6 implementations in cellular devices. @@ -269,187 +305,94 @@ C_REC#5: If the cellular host receives the DNS information in several channels for the same interface, the following preference order must be followed: 1. PCO 2. RA 3. DHCPv6 + The purpose of this recommendation is to guarantee for a + deterministic behavior to be followed by all cellular hosts + when the DNS information is received in various channels. + C_REC#6: The cellular host must be able to be configured to limit PDP type(s) for a given APN. The default mode is to allow all supported PDP types. Note, C_REC#2 discusses the default behavior for requesting PDP-Context type(s). This feature is useful to drive the behavior of the UE to be aligned with: (1) service-specific constraints such as the use of IPv6-only for VoLTE (Voice over LTE), (2) network conditions with regards to the support of specific PDP types (e.g., IPv4v6 PDP-Context is not supported), (3) IPv4 sunset objectives, (4) subscription data, etc. Note, a cellular host changing its connection between an IPv6-specific APN and an IPv4-specific APN restarts the - ongoing applications. This is a brokenness situation. + ongoing applications. This may be considered as a + brokenness situation. C_REC#7: Because of potential operational deficiencies to be experienced in some roaming situations, the cellular host - must be able to be configured with a home IP profile and a - roaming IP profile. The aim of the roaming profile is to - limit the PDP type(s) requested by the cellular host when - out of the home network. Note that distinct PDP type(s) - and APN(s) can be configured for home and roaming cases. + must be able to be configured with a home PDP-Context + type(s) and a roaming PDP-Context type(s). The purpose of + the of the roaming profile is to limit the PDP type(s) + requested by the cellular host when out of the home + network. Note that distinct PDP type(s) and APN(s) can be + configured for home and roaming cases. + + A detailed analysis of roaming failure cases is included + in [RFC7445]. C_REC#8: In order to ensure IPv4 service continuity in an IPv6-only deployment context, the cellular host should support a method to locally construct IPv4-embedded IPv6 addresses [RFC6052]. A method to learn PREFIX64 should be supported by the cellular host. This solves the issue when applications use IPv4 referrals on IPv6-only access networks. In PCP-based environments, cellular hosts should follow [RFC7225] to learn the IPv6 Prefix used by an upstream PCP-controlled NAT64 device. If PCP is not enabled, the cellular host should implement the method specified in [RFC7050] to retrieve the PREFIX64. C_REC#9: In order to ensure IPv4 service continuity in an IPv6-only deployment context, the cellular host should implement the - Customer Side Translator (CLAT, [RFC6877]) function which - is compliant with [RFC6052][RFC6145][RFC6146]. + Customer Side Translator (CLAT, [RFC6877]) function in + compliance with [RFC6052][RFC6145][RFC6146]. CLAT function in the cellular host allows for IPv4-only application and IPv4-referals to work on an IPv6-only - connectivity. CLAT function requires a NAT64 capability - [RFC6146] in the core network. + connectivity. The more applications are address family + independent, the less CLAT function is solicited. CLAT + function requires a NAT64 capability [RFC6146] in the + network. + + The cellular host should only invoke the CLAT in the + absence of the IPv4 connectivity on the cellular side, + i.e., when the network does not assign an IPv4 address + on the cellular interface. Note, NAT64 assumes an + IPv6-only mode [RFC6146]. The IPv4 Service Continuity Prefix used by CLAT is defined in [RFC7335]. -2.1. WLAN Connectivity Recommendations - - It is increasingly common for cellular hosts have a WLAN interface in - addition to their cellular interface. These hosts are likely to be - connected to private or public hotspots. Below are listed some - generic recommendations: - - W_REC#1: IPv6 must be supported on the WLAN interface. In - particular, WLAN interface must behave properly when only - an IPv6 connectivity is provided. - - Some tests revealed that IPv4 configuration is required - to enable IPv6-only connectivity. Indeed, some cellular - handsets can access a WLAN IPv6-only network by - configuring first a static IPv4 address. Once the - device is connected to the network and the wlan0 - interface got an IPv6 global address, the IPv4 address - can be deleted from the configuration. This avoids the - device to ask automatically for a DHCPv4 server, and - allows to connect to IPv6-only networks. Failing to - configure an IPv4 address on the interface must not - prohibit using IPv6 on the same interface. - - W_REC#2: If the device receives the DNS information in several - channels for the same interface, the following preference - order must be followed: - - 1. RA - - 2. DHCPv6 - -3. Advanced Recommendations - - This section identifies a set of advanced recommendations to fulfill - requirements of critical services such as VoLTE. - - A_REC#1: The cellular host must support ROHC RTP Profile (0x0001) - and ROHC UDP Profile (0x0002) for IPv6 ([RFC5795]). Other - ROHC profiles may be supported. - - Bandwidth in cellular networks must be optimized as much - as possible. ROHC provides a solution to reduce - bandwidth consumption and to reduce the impact of having - bigger packet headers in IPv6 compared to IPv4. - - "RTP/UDP/IP" ROHC profile (0x0001) to compress RTP - packets and "UDP/IP" ROHC profile (0x0002) to compress - RTCP packets are required for Voice over LTE (VoLTE) by - IR.92.4.0 section 4.1 [IR92]. Note, [IR92] indicates - also the host must be able to apply the compression to - packets that are carried over the radio bearer dedicated - for the voice media. - - A_REC#2: The cellular host should support PCP [RFC6887]. - - The support of PCP is seen as a driver to save battery - consumption exacerbated by keepalive messages. PCP also - gives the possibility of enabling incoming connections - to the cellular device. Indeed, because several - stateful devices may be deployed in wireless networks - (e.g., NAT and/or Firewalls), PCP can be used by the - cellular host to control network-based NAT and Firewall - functions which will reduce per-application signaling - and save battery consumption. - - According to [Power], the consumption of a cellular - device with a keep-alive interval equal to 20 seconds - (that is the default value in [RFC3948] for example) is - 29 mA (2G)/34 mA (3G). This consumption is reduced to - 16 mA (2G)/24 mA (3G) when the interval is increased to - 40 seconds, to 9.1 mA (2G)/16 mA (3G) if the interval is - equal to 150 seconds, and to 7.3 mA (2G)/14 mA (3G) if - the interval is equal to 180 seconds. When no keep- - alive is issued, the consumption would be 5.2 mA - (2G)/6.1 mA (3G). The impact of keepalive messages - would be more severe if multiple applications are - issuing those messages (e.g., SIP, IPsec, etc.). - - A_REC#3: In order for host-based validation of DNS Security - Extensions (DNSSEC) to continue to function in an IPv6-only - with NAT64 deployment context, the cellular host should - embed a DNS64 function ([RFC6147]). - - This is called "DNS64 in stub-resolver mode" in - [RFC6147]. - - As discussed in Section 5.5 of [RFC6147], a security- - aware and validating host has to perform the DNS64 - function locally. - - Because synthetic AAAA records cannot be successfully - validated in a host, learning the PREFIX64 used to - construct IPv4-converted IPv6 addresses allows the use - of DNSSEC [RFC4033] [RFC4034], [RFC4035]. Means to - configure or discover a PREFIX64 are required on the - cellular device as discussed in C_REC#8. - - [RFC7051] discusses why a security-aware and validating - host has to perform the DNS64 function locally and why - it has to be able to learn the proper PREFIX64(s). - - A_REC#4: When the cellular host is dual-stack connected (i.e., - configured with an IPv4 address and IPv6 prefix), it should - support means to prefer native IPv6 connection over - connection established through translation devices (e.g., - NAT44 and NAT64). - - When both IPv4 and IPv6 DNS servers are configured, a - dual-stack host must contact first its IPv6 DNS server. - - Cellular hosts should follow the procedure specified in - [RFC6724] for source address selection. + CLAT and/or NAT64 do not interfere with native IPv6 + communications. -4. Recommendations for Cellular Devices with LAN Capabilities +3. Recommendations for Cellular Devices with LAN Capabilities This section focuses on cellular devices (e.g., CPE, smartphones, or dongles with tethering features) which provide IP connectivity to other devices connected to them. In such case, all connected devices are sharing the same 2G, 3G or LTE connection. In addition to the generic recommendations listed in Section 2, these cellular devices have to meet the recommendations listed below. L_REC#1: The cellular device must support Prefix Delegation capabilities [RFC3633] and must support Prefix Exclude @@ -497,99 +440,180 @@ countries, that relies on mobile networks to provide broadband services (e.g., customers are provided with mobile CPEs). Note, this profile does not require IPv4 service continuity techniques listed in [RFC7084] because those are specific to fixed networks. IPv4 service continuity techniques specific to the mobile networks are included in this profile. - CAUTION: This recommendation does not apply to any - cellular device with LAN capabilities; it is specific to - cellular CPEs in order to ensure the same IPv6 - functional parity for both fixed and cellular CPEs. + This recommendation does not apply to handsets with + tethering capabilities; it is specific to cellular CPEs + in order to ensure the same IPv6 functional parity for + both fixed and cellular CPEs. Note, modern CPEs are + designed with advanced functions such as link + aggregation that consists in optimizing the network + usage by aggregating the connectivity resources offered + via various interfaces (e.g., DSL, LTE, WLAN, etc.) or + offloading the traffic via a subset of interfaces. + Mutualizing IPv6 features among these interface types is + important for the sake of specification efficiency, + service design simplification and validation effort + optimization. L_REC#3: For deployments requiring to share the same /64 prefix, the cellular device should support [RFC7278] to enable sharing a /64 prefix between the 3GPP interface towards the GGSN/ PGW (WAN interface) and the LAN interfaces. Prefix Delegation (refer to L_REC#1) is the target solution for distributing prefixes in the LAN side but, because the device may attach to earlier 3GPP release networks, a mean to share a /64 prefix is also recommended [RFC7278]. [RFC7278] must be invoked only if Prefix Delegation is not in use. - L_REC#4: In order to ensure IPv4 service continuity in an IPv6-only + L_REC#4: In order to allow IPv4 service continuity in an IPv6-only deployment context, the cellular device should support the Customer Side Translator (CLAT) [RFC6877]. Various IP devices are likely to be connected to cellular device, acting as a CPE. Some of these devices can be dual-stack, others are IPv6-only or IPv4-only. IPv6-only connectivity for cellular device does not allow IPv4-only sessions to be established for hosts connected on the LAN segment of cellular devices. In order to allow IPv4 sessions establishment initiated from devices located on LAN segment side and target IPv4 nodes, a solution consists in integrating the CLAT function in the cellular device. As elaborated in Section 2, the CLAT function allows also IPv4 - applications to continue running over an IPv6-only host. + applications to continue running over an IPv6-only + device. + + The cellular host should only invoke the CLAT in the + absence of the IPv4 connectivity on the cellular side, + i.e., when the network does not assign an IPv4 address + on the cellular interface. The IPv4 Service Continuity Prefix used by CLAT is defined in [RFC7335]. L_REC#5: If a RA MTU is advertised from the 3GPP network, the cellular device should relay that upstream MTU information to the downstream attached LAN devices in RA. Receiving and relaying RA MTU values facilitates a more harmonious functioning of the mobile core network where end nodes transmit packets that do not exceed the MTU size of the mobile network's GTP tunnels. [TS.23060] indicates providing a link MTU value of 1358 octets to the 3GPP cellular device will prevent the IP layer fragmentation within the transport network between the cellular device and the GGSN/PGW. -5. APIs & Applications Recommendations +4. Advanced Recommendations - The use of address family dependent APIs (Application Programming - Interfaces) or hard-coded IPv4 address literals may lead to broken - applications when IPv6 connectivity is in use. This section - identifies a set of recommendations aiming to minimize broken - applications when the cellular device is attached to an IPv6 network. + This section identifies a set of advanced recommendations to fulfill + requirements of critical services such as VoLTE. - APP_REC#1: Name resolution libraries must support both IPv4 and - IPv6. + A_REC#1: The cellular host must support ROHC RTP Profile (0x0001) + and ROHC UDP Profile (0x0002) for IPv6 ([RFC5795]). Other + ROHC profiles may be supported. - In particular, the cellular host must support - [RFC3596]. + Bandwidth in cellular networks must be optimized as much + as possible. ROHC provides a solution to reduce + bandwidth consumption and to reduce the impact of having + bigger packet headers in IPv6 compared to IPv4. - APP_REC#2: Applications provided by the mobile device vendor must be - independent of the underlying IP address family. + "RTP/UDP/IP" ROHC profile (0x0001) to compress RTP + packets and "UDP/IP" ROHC profile (0x0002) to compress + RTCP packets are required for Voice over LTE (VoLTE) by + IR.92.4.0 section 4.1 [IR92]. Note, [IR92] indicates + that the host must be able to apply the compression to + packets that are carried over the voice media dedicated + radio bearer. - This means applications must be IP version agnostic. + A_REC#2: The cellular host should support PCP [RFC6887]. - APP_REC#3: Applications provided by the mobile device vendor that - use Uniform Resource Identifiers (URIs) must follow - [RFC3986] and its updates. For example, SIP applications - must follow the correction defined in [RFC5954]. + The support of PCP is seen as a driver to save battery + consumption exacerbated by keepalive messages. PCP also + gives the possibility of enabling incoming connections + to the cellular device. Indeed, because several + stateful devices may be deployed in wireless networks + (e.g., NAT64 and/or IPv6 Firewalls), PCP can be used by + the cellular host to control network-based NAT64 and + IPv6 Firewall functions which will reduce per- + application signaling and save battery consumption. -6. Security Considerations + According to [Power], the consumption of a cellular + device with a keep-alive interval equal to 20 seconds + (that is the default value in [RFC3948] for example) is + 29 mA (2G)/34 mA (3G). This consumption is reduced to + 16 mA (2G)/24 mA (3G) when the interval is increased to + 40 seconds, to 9.1 mA (2G)/16 mA (3G) if the interval is + equal to 150 seconds, and to 7.3 mA (2G)/14 mA (3G) if + the interval is equal to 180 seconds. When no keep- + alive is issued, the consumption would be 5.2 mA + (2G)/6.1 mA (3G). The impact of keepalive messages + would be more severe if multiple applications are + issuing those messages (e.g., SIP, IPsec, etc.). + + PCP allows to avoid embedding ALGs (Application Level + Gateways) at the network side (e.g., NAT64) to manage + protocols which convey IP addresses and/or port numbers + (see Section 2.2 of [RFC6889]). Avoiding soliciting + ALGs allows for more easiness to make evolve a service + independently of the underlying transport network. + + A_REC#3: In order for host-based validation of DNS Security + Extensions (DNSSEC) to continue to function in an IPv6-only + connectivity with NAT64 deployment context, the cellular + host should embed a DNS64 function ([RFC6147]). + + This is called "DNS64 in stub-resolver mode" in + [RFC6147]. + + As discussed in Section 5.5 of [RFC6147], a security- + aware and validating host has to perform the DNS64 + function locally. + + Because synthetic AAAA records cannot be successfully + validated in a host, learning the PREFIX64 used to + construct IPv4-converted IPv6 addresses allows the use + of DNSSEC [RFC4033] [RFC4034], [RFC4035]. Means to + configure or discover a PREFIX64 are required on the + cellular device as discussed in C_REC#8. + + [RFC7051] discusses why a security-aware and validating + host has to perform the DNS64 function locally and why + it has to be able to learn the proper PREFIX64(s). + + A_REC#4: When the cellular host is dual-stack connected (i.e., + configured with an IPv4 address and IPv6 prefix), it should + support means to prefer native IPv6 connection over + connection established through translation devices (e.g., + NAT44 and NAT64). + + When both IPv4 and IPv6 DNS servers are configured, a + dual-stack host must contact first its IPv6 DNS server. + This preference allows to offload IPv4-only DNS servers. + + Cellular hosts should follow the procedure specified in + [RFC6724] for source address selection. + +5. Security Considerations The security considerations identified in [RFC7066] and [RFC6459] are to be taken into account. In the case of cellular CPEs, compliance with L_REC#2 entails compliance with [RFC7084], which in turn recommends compliance with Recommended Simple Security Capabilities in Customer Premises Equipment (CPE) for Providing Residential IPv6 Internet Service [RFC6092]. Therefore, the security considerations in Section 6 of [RFC6092] are relevant. In particular, it bears repeating here that @@ -602,44 +626,43 @@ The cellular host must be able to generate IPv6 addresses which preserve privacy. The activation of privacy extension (e.g., using [RFC7217]) makes it more difficult to track a host over time when compared to using a permanent Interface Identifier. Tracking a host is still possible based on the first 64 bits of the IPv6 address. Means to prevent against such tracking issues may be enabled in the network side. Note, privacy extensions are required by regulatory bodies in some countries. Host-based validation of DNSSEC is discussed in A_REC#3 (see - Section 3). + Section 4). -7. IANA Considerations +6. IANA Considerations This document does not require any action from IANA. -8. Acknowledgements +7. Acknowledgements Many thanks to C. Byrne, H. Soliman, H. Singh, L. Colliti, T. Lemon, B. Sarikaya, M. Mawatari, M. Abrahamsson, P. Vickers, V. Kuarsingh, E. Kline, S. Josefsson, A. Baryun, J. Woodyatt, T. - Kossut, B. Stark, and A. Petrescu for the discussion in the v6ops - mailing list. + mailing list and for the comments. Thanks to A. Farrel, B. Haberman and K. Moriarty for the comments during the IESG review. Special thanks to T. Savolainen, J. Korhonen, J. Jaeggli, and F. Baker for their detailed reviews and comments. -9. References +8. References -9.1. Normative References +8.1. Normative References [IR92] GSMA, "IR.92.V4.0 - IMS Profile for Voice and SMS", March 2011, . [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998. [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, "DNS Extensions to Support IP Version 6", RFC 3596, @@ -682,21 +705,21 @@ 3GPP, "General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access", September 2011, . [TS.24008] 3GPP, "Mobile radio interface Layer 3 specification; Core network protocols; Stage 3", June 2011, . -9.2. Informative References +8.2. Informative References [OECD] Organisation for Economic Cooperation and Development (OECD), "The Economics of the Transition to Internet Protocol version 6 (IPv6)", November 2014, . [Power] Haverinen, H., Siren, J., and P. Eronen, "Energy Consumption of Always-On Applications in WCDMA Networks", April 2007, . Authors' Addresses David Binet France Telecom Rennes @@ -826,10 +857,27 @@ EMail: nick.heatley@ee.co.uk Ross Chandler eircom | meteor 1HSQ St. John's Road Dublin 8 Ireland EMail: ross@eircom.net + + Dave Michaud + Rogers Communications + 8200 Dixie Rd. + Brampton, ON L6T 0C1 + Canada + + EMail: dave.michaud@rci.rogers.com + + Diego R. Lopez + Telefonica I+D + Don Ramon de la Cruz, 82 + Madrid 28006 + Spain + + Phone: +34 913 129 041 + EMail: diego.r.lopez@telefonica.com