--- 1/draft-ietf-v6ops-unique-ipv6-prefix-per-host-00.txt 2016-07-08 15:18:07.036611336 -0700 +++ 2/draft-ietf-v6ops-unique-ipv6-prefix-per-host-01.txt 2016-07-08 15:18:07.052611736 -0700 @@ -1,19 +1,19 @@ v6ops J. Brzozowski Internet-Draft Comcast Cable Intended status: Best Current Practice G. Van De Velde -Expires: April 21, 2016 Alcatel-Lucent - October 19, 2015 +Expires: November 11, 2016 Nokia + May 10, 2016 Unique IPv6 Prefix Per Host - draft-ietf-v6ops-unique-ipv6-prefix-per-host-00 + draft-ietf-v6ops-unique-ipv6-prefix-per-host-01 Abstract In some IPv6 environments the need has arisen for hosts to be able to utilise a unique IPv6 prefix even though the link or media may be shared. Typically hosts (subscribers) on a shared network, like Wi- Fi or Ethernet, will acquire unique IPv6 addresses from a common IPv6 prefix that is allocated or assigned for use on a specific link. Benefits of a unique IPv6 prefix compared to a unique IPv6 address from the service provider are going from enhanced subscriber @@ -38,520 +38,246 @@ 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 April 21, 2016. + This Internet-Draft will expire on November 11, 2016. Copyright Notice - Copyright (c) 2015 IETF Trust and the persons identified as the + Copyright (c) 2016 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 2. Motivation and Scope of Applicability . . . . . . . . . . . . 3 - 3. Design Princinples . . . . . . . . . . . . . . . . . . . . . 4 - 4. Behaviour . . . . . . . . . . . . . . . . . . . . . . . . . . 4 - 4.1. Community Wi-Fi Network Topology Description . . . . . . 4 - 4.2. Wi-Fi Subscriber Onboarding Procedures . . . . . . . . . 6 - 4.3. UE IPv6 Addressing and Configuration . . . . . . . . . . 10 - 4.3.1. IPv6 Addressing . . . . . . . . . . . . . . . . . . . 10 - 4.3.2. IPv6 Configuration . . . . . . . . . . . . . . . . . 11 - 5. Operational Considerations . . . . . . . . . . . . . . . . . 11 - 6. Future work . . . . . . . . . . . . . . . . . . . . . . . . . 13 - 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 - 8. Security Considerations . . . . . . . . . . . . . . . . . . . 13 - 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 - 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 - 10.1. Normative References . . . . . . . . . . . . . . . . . . 13 - 10.2. Informative References . . . . . . . . . . . . . . . . . 14 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 + 3. Design Princinples . . . . . . . . . . . . . . . . . . . . . 3 + 4. IPv6 Unique Prefix Assignment . . . . . . . . . . . . . . . . 4 + 5. IPv6 Neighbourship Discovery Best Practices . . . . . . . . . 5 + 6. Future work . . . . . . . . . . . . . . . . . . . . . . . . . 6 + 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 + 8. Security Considerations . . . . . . . . . . . . . . . . . . . 6 + 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 + 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 + 10.1. Normative References . . . . . . . . . . . . . . . . . . 7 + 10.2. Informative References . . . . . . . . . . . . . . . . . 7 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 1. Introduction - The concepts in this document were originally developed as part of a - large scale, production deployment of IPv6 support for a community - Wi-Fi service. In this document IPv6 support does not preclude - support for IPv4, however, the primary objectives for this work was - to make it so that user equipment (UE) were capable of an IPv6 only - experience from a network operators perspective. Details of IPv4 - support are out of scope for this document. This document will also, - in general, outline the requirements that must be satified by UE to - allow for an IPv6 only experience. + The concepts in this document are originally developed as part of a + large scale, production deployment of IPv6 support for a provider + managed shared network service. In this document IPv6 support does + not preclude support for IPv4, however, the primary objectives for + this work was to make it so that user equipment (UE) were capable of + an IPv6 only experience from a network operators perspective. + Details of IPv4 support are out of scope for this document. This + document will also, in general, outline the requirements that must be + satified by UE to allow for an IPv6 only experience. In most deployments today User Equipment (UE) IPv6 address assignment is commonly done using either IPv6 SLAAC RFC4862 [RFC4862] and/or DHCP IA_NA RFC3315 [RFC3315]. However, at current time there is a non-trivial UE/subscriber base not supporting DHCPv6 IA_NA, making - IPv6 SLAAC based subscriber and address management for community Wi- - Fi services the technology of choice as it does not exclude any known - IPv6 implementation. This document will detail the mechanics - involved for IPv6 SLAAC based address and subscriber management - coupled with stateless DHCPv6, where beneficial. - - A community Wi-Fi service is an environment to allow subscribers - (hosts) to connect to a shared network providing Internet and/or - closed network services. Often Service providers use community Wi-Fi - networks to provide enhanced subscriber connectivity experiences. - Additionally retail owners frequently provide community Wi-Fi - services to improve their customers retail experience. + IPv6 SLAAC based subscriber and address management for provider + managed shared network services the technology of choice as it does + not exclude any known IPv6 implementation. This document will detail + the mechanics involved for IPv6 SLAAC based address and subscriber + management coupled with stateless DHCPv6, where beneficial. - Upon further exploration the approach documented here has - applicability in other environments including corporate, enterprise, - or university settings where IPv6 support is desired over a shared - media. Where applicable details related to the same will be - provided. + This document will focus upon the process for UEs to obtain a unique + IPv6 prefix. 2. Motivation and Scope of Applicability The motivation for this work falls into the following categories: - o Deploy support for IPv6 that will allow for an IPv6 only - experience, even if IPv4 support is present + o Deployment advice for IPv6 that will allow stable and secure IPv6 + only experience, even if IPv4 support is present o Ensure support for IPv6 is efficient and does not impact the performance of the underlying network and in turn the customer experience o Allow for the greatest flexibility across host implementation to allow for the widest range of addressing and configuration mechanisms to be employed. The goal here is the ensure that the widest population of UE implementations can leverage the - availability of IPv6. + availability of IPv6 o Lay the technological foundation for future work related to the - use of IPv6 over shared media like Wi-Fi - - While this work was originally conceived in the context of large - scale Wi-Fi networks, the scope of applicability is much broader. - The techniques and concepts or subsets of the same may also be - applicable in residential or SOHO networking environments. - -3. Design Princinples - - The Wireless LAN Gateway (WLAN-GW) discussed in this document is the - L3-Edge router responsible for the communication with the Wi-Fi - subscribers (hosts) and to aggregate the traffic from the Wi-Fi - subscribers and the Wireless LAN network towards the community Wi-Fi - provider. - - The goal of a WLAN-GW is to provide sufficient data-plane throughput - capacity to aggregate all Wi-Fi subscriber traffic, while at the same - time it is functioning as control-plane anchor point to make sure - that each subscriber is receiving the expected subscriber policy and - service levels (throughput, QoS, security, parental-control, - subscriber mobility management, etc.). - - The work detailed in this document intends to provide details - regarding the WLAN-GW Wi-Fi subscriber/host addressing methodology. - Evolved WLAN-GW capabilities regarding fixed/mobile convergence, - traffic steering, etc. are not the main focus and are outside the - scope of this document. - -4. Behaviour - - This section outlines the essential components of the described - system and interaction amongst the same. - -4.1. Community Wi-Fi Network Topology Description - - The topology and design referenced in this document is a generalized - description of functional components currently deployed in a large - scale subscriber oriented network. - - +-----+ - | AAA | - +-----+ - / - Radius - / - +----+ - | CP | - +----+ +---------+ - UE--802.11--| AP |---Soft_GRE---| WLAN-GW |----Internet/WAN access - +----+ +---------+ - | - IP/HTTP - | - +---------------------+ - | HTTP Captive Portal | - +---------------------+ - - Figure 1 - - o UE: User Equipment. - - o 802.11: Wireless Network - - o AP: Access Point. - - o Soft-GRE: Stateless GRE tunnel - - o WLAN-GW: Wireless LAN Gateway - - o CP: Control Plane component of the WLAN-GW - - o AAA: Accounting, Authorisation and Authentication - - o HTTP Captive Portal: Captive portal used to redirect traffic - towards during subscriber onboarding process - - While there are many ways for UE to associate to a Wi-Fi network - (e.g. EAP-SIM, EAP-AKA, WPA2-PSK, etc.), community Wi-Fi - predominantly leverages an HTTP Captive Portal. The key function for - the Captive Portal is to identify the UE/subscriber and create on the - WLAN-GW the corresponding UE/subscriber context for policy and - accounting. - - The Soft-GRE session is a stateless GRE tunnel between AP and the - WLAN-GW. The AP is configured with the IP address or FQDN of the - tunnel concentrator or aggregation point and initiates the GRE - tunnel, over IPv6 preferrably, by encapsulating packets towards the - WLAN-GW. The WLAN-GW is configured as a GRE tunnel head-end server - and accepts these GRE packets, while at the same time creating - correct tunnel context to identify the AP. Soft-GRE is a very well - established pragmatic technology. The use of GRE over IPv4 only - furthers an operators dependence on IPv4 and should be deprecated by - using GRE over IPv6 only. - - The AP has, as seen in the illustration, an interface attached to the - Wi-Fi network and will bridge traffic received on this Wi-Fi - interface over the Soft-GRE tunnel to the WLAN-GW. This will include - traffic from newly attached UE/subscribers which have not been - identified or authorized on the Wi-Fi network. At the same time the - AP implements split-horizon for BUM (broadcast, unknown and - multicast) traffic, making sure that there is no undesired leakage of - traffic between UE/subscribers attached to the Wi-Fi network. - - The Control Plane (CP) of the WLAN-GW is a key component used during - onboarding of UE/subscribers to identify the UE/subscriber and to - exchange IP address related details. For that purpose it can make - usage of DHCP, ARP, DHCPv6, ICMPv6 (RS/RA/NS/NA), Radius, Diameter, - etc. - -4.2. Wi-Fi Subscriber Onboarding Procedures + use of IPv6 over shared media requiring optimized subscriber + management - This section provides detail about Best Practice operational steps to - onboard a UE/subscriber and the key architectural technology used to - create the WLAN-GW UE/subscriber policy and IP addressing context. + o Two devices (subscriber/hosts), both attached to the same provider + managed shared network should only be able to communicate through + the provider managed First Hop Router - The flow chart pictured below is providing a sequential overview of - the operational steps performed to onboard a UE onto a community Wi- - Fi network. + o Provide guidelines regarding best common practices around IPv6 + neighborship discovery and IPv6 address managent settings between + the First Hop router and directly connected hosts/subscribers. - UE WLAN-GW AAA Captive-Portal DNS - | | | | | - | | | | | - |--------RS-------->| | | | - | |---Access-Req---->| | | - | |<--Access-Acc-----| | | - | |(=Radius UE info) | | | - |<-------RA---------| | | | - |(/64; M,L=0; O,A=1)| | | | - | | | | | - |------NS(DAD)----->| | | | - | | | | | - |-DHCPv6(info Req)->| | | | - | (Ask DNS IP addr.)| | | | - | | | | | - |<---DHCPv6 Reply---| | | | - | | | | | - |--------------------------------DNS----------------------------->| - | | | | | - |------HTTP GET---->| | | | - |<--HTTP Redirect---| | | | - | | | | | - |--------------------------------DNS----------------------------->| - | | | | | - |<------------------------HTTP Login------------------->| | - | | | | | - | | |<-UE Identified-| | - | |<--Radius CoA-----| | | - | |(remove HTTP Red.)| | | - | | | | | - |<--------UE/Subscriber connected to Internet/WAN-------------------> - | | | | | - | | | | | +3. Design Princinples - Figure 2 + The First Hop router discussed in this document is the L3-Edge router + responsible for the communication with the devices (hosts and + subscribers) directly connected to a provider managed shared network, + and to transport traffic between the directly connected devices and + between directy connected devices and remote devices. - Note that the Wireless Access Point (AP) is not pictured in the flow - chart above. This is because the AP is from architectural - perspective functioning as a L2 bridge between the UE and WLAN-GW. - For Wi-Fi community service the AP is configured to setup a Soft-GRE - tunnel towards the WLAN-GW and to bridge relevant Wi-Fi traffic upon - the Soft-GRE tunnel. The AP is also configured for split-horizon - towards the Wi-Fi interface for subscriber isolation and security - purpose. The AP will for the remainder of this document be silently - inserted between UE and WLAN-GW to bridge traffic between the WLAN-GW - and AP and vice versa - When a new UE connects to the community Wi-Fi it connects to the Wi- - Fi network by attaching to the relevant 'open' SSID advertised for - use as part of the community Wi-Fi offering. Once the UE/subscriber - is attached to the Wi-Fi SSID it will initiate IP configuration. The - focus of this document is to share IPv6 address assignment Best - Practices, and hence will focus around those topics, eventhough there - are many more aspects to deploy a quality community Wi-Fi service - offering successfully. + The work detailed in this document is focussed to provide details + regarding best common practices of the IPv6 neighborship discovery + and related IPv6 address management settings between the First Hop + router and directly connected hosts/subscribers. The documented Best + Current Practice helps a service provider to better manage the shared + provider managed network on behalf of the connected devices. - Once the UE is connected to the Wi-Fi shared network, it will from an - IPv6 perspective attempt to learn the default IPv6 gateway, the IPv6 - prefix information, the DNS information, and the remaining - information required to establish globally routable IPv6 - connectivity. For that purpose the the UE/subscriber sends a RS - (Router Solicitation) message. This RS is forwarded by the AP-bridge - over the Soft-GRE interface, however due to the split-horizon - configuration for BUM traffic it is not relayed to any other UE/ - Subscribers attached to the Wi-Fi network. + The Best Current Practice documented in this note is to provide + hosts/subscribers devices connected to the provider managed shared + network with a unique IPv6 prefix while at the same functioning as + control-plane anchor point to make sure that each subscriber is + receiving the expected subscriber policy and service levels + (throughput, QoS, security, parental-control, subscriber mobility + management, etc.). - The WLAN-GW received this UE/subscriber RS message, and because it is - the first time this UE/subscriber attaches to the Wi-Fi the UE/ - subscriber is by default not authorized. The WLAN-GW will now try to - discover additional information about the subscriber information by - querying the AAA server. This is done by sending a Radius Access- - Request. +4. IPv6 Unique Prefix Assignment - The Radius server receives this Access-Request, and performs a lookup - in its policy database. If radius server discovers that the UE/ - subscriber is a fresh device trying to gain access onto the Wi-Fi - network it will identify some parameters (e.g. IPv6 /64 prefix) to - send back to the WLAN-GW together with a message to install a HTTP- - redirect to a Captive Portal for further UE/subscriber - identification. This will be sent from the AAA server to the WLAN-GW - in a Radius Access-Ackowledge message. + When a UE connects to the shared provider managed network and is + attached it will initiate IP configuration phase. During this phase + the UE will from an IPv6 perspective attempt to learn the default + IPv6 gateway, the IPv6 prefix information, the DNS information, and + the remaining information required to establish globally routable + IPv6 connectivity. For that purpose the the UE/subscriber sends a RS + (Router Solicitation) message. - The WLAN-GW will use the received Radius information to compose the - response to the UE/subscriber originated RS message. The WLAN-GW - will answer using a unicast RA (Router Advertisement) to the UE/ - subscriber. This RA contains a few important parameters for the EU/ - subscriber to consume: (1) a /64 prefix and (2) flags. The /64 - prefix can be derived from a locally managed pool or aggregate IPv6 - block assigned to the WLAN-GW or from a pool signalled by the Radius - server in a radius attribute. The flags may indicate to the UE/ - subscriber to use SLAAC and/or DHCPv6 for address assignment, it may - indicate if the autoconfigured address is on/off-link and if 'Other' - information (e.g. DNS server address) needs to be requested. + The First Hop Router receives this UE/subscriber RS message and + starts the process to compose the response to the UE/subscriber + originated RS message. The First Hop Provider Router will answer + using a unicast RA (Router Advertisement) to the UE/subscriber. This + RA contains a few important parameters for the EU/subscriber to + consume: (1) a /64 prefix and (2) flags. The /64 prefix can be + derived from a locally managed pool or aggregate IPv6 block assigned + to the First Hop Provider Router or from a centrally allocated pool. + The flags indicate to the UE/subscriber to use SLAAC and/or DHCPv6 + for address assignment, it may indicate if the autoconfigured address + is on/off-link and if 'Other' information (e.g. DNS server address) + needs to be requested. The IPv6 RA flags used for best common practice in IPv6 SLAAC based - community Wi-Fi are: + Provider managed shared networks are: o M-flag = 0 (UE/subscriber address is not managed through DHCPv6), this flag may be set to 1 in the future if/when DHCPv6 prefix - delegation support over Wi-Fi is desired) + delegation support is desired) o O-flag = 1 (DHCPv6 is used to request configuration information i.e. DNS, NTP information, not for IPv6 addressing) o A-flag = 1 (The UE/subscriber can configure itself using SLAAC) - o L-flag = 0 (The UE/subscriber is off-link, which means that the UE/subscriber will send packets ALWAYS to his default gateway, even if the destination is within the range of the /64 prefix) The use of a unique IPv6 prefix per UE adds an additional level of protection and efficiency as it relates to how IPv6 Neighbor Discovery and Router Discovery processing. Since the UE has a unique - IPv6 prefix all traffic by default will be directed to the WLAN-GW. - Further, the flag combinations documented above maximize the IPv6 - configurations that are available by hosts including the use of - privacy IPv6 addressing. + IPv6 prefix all traffic by default will be directed to the First Hop + provider router. Further, the flag combinations documented above + maximize the IPv6 configurations that are available by hosts + including the use of privacy IPv6 addressing. The architected result of designing the RA as documented above is that each UE/subscriber gets its own unique /64 IPv6 prefix for which it can use SLAAC or any other method to select its /128 unique address. In addition it will use stateless DHCPv6 to get the IPv6 address of the DNS server, however it SHOULD NOT use stateful DHCPv6 to receive a service provider managed IPv6 address. If the UE/ subscriber desires to send anything external including other UE/ subscriber devices (assuming device to device communications is enabled and supported), then due to the L-bit set it SHOULD send this - traffic to the WLAN-GW. + traffic to the First Hop Provider Router. Now that the UE/subscriber received the RA and the associated flags, it will assign itself a 128 bit IPv6 address using SLAAC. Since the address is composed by the UE/subscriber device itself it will need to verify that the address is unique on the shared network. The UE/ subscriber will for that purpose perform Duplicate Address Detection algorithm. This will occur for each address the UE attempts to - utilize on the Wi-Fi network. - - At this stage the UE/subscriber has acquired a valid IPv6 address, - however it may not have received one or more DNS server IPv6 address. - The UE/subscriber can use stateless DHCPv6 exchange to identify a - valid DNS server address(es). An alternative solution, albeit less - supported by IPv6 hosts is to signal DNS server addresses is by - utilising RA extensions described in RNDSS RFC6106 [RFC6106] in which - the router uses Router Advertisement options to advertise a list of - DNS recursive server addresses and a DNS Search List to IPv6 UE/ - subscribers. The use of RNDSS and stateless DHCPv6 for the - configuration of hosts are not mutually exclusive. Both methods can - and should be enabled simultaneously allowing for the widest range of - hosts or UEs to learn and use DNS over IPv6. DNS server IPv6 - address(es) sent via DHCPv6 and RDNSS must be identical. - - At this moment the UE/subscriber has all information to be connected - to the Internet, nevertheless the community Wi-Fi service provider - has no idea about the identity or credentials of the UE/subscriber. - For that purpose the Service provider has installed on the WLAN-GW a - HTTP redirect for this particular UE/subscriber towards HTTP captive - portal. First the subscriber utilises DNS to correlate the domain - name with an IP address, next the HTTP GET is intercepted and an HTTP - Redirect is issued to Redirect the HTTP session towards the Captive - portal. The ultimate goal of this process is for the service - provider to identify the UE/subscriber. From the moment the UE/ - subscriber identified itself on the captive portal (login-ID/PW, PIN - Challenge, etc.) then the captive portal informs the WLAN-GW about - the correct policies (QoS, policing, etc.) and to remove the HTTP- - redirect. - - From now onwards the WLAN-GW has identified the UE/subscriber and - installed all the subscriber context for identification, billing, - traffic conditioning. The UE/subscriber can access the Internet/WAN - within his agreed commuity Wi-Fi parameters. - -4.3. UE IPv6 Addressing and Configuration - - An over arching objective for any IPv6 deployment where subscriber - endpoints or UEs are concerned must include an IPv6 only experience. - Specifically, similar to residential broadband networks, Wi-Fi - networks that support IPv6 must ensure there are no dependencies on - IPv4. Due to fragmented support for various IPv6 address and - configuration mechanisms network operators must effectively enable - and support every combination of IPv6 address and configuration - technique. Coordinating the configuraiton and values for the same is - important to ensure proper UE behavior. - -4.3.1. IPv6 Addressing - - Stateless IPv6 address autoconfiguration is expected to be the - primary mechanism for UEs to leverage when establing globally - routable IPv6 connectivity. Stateful DHCPv6 is currently not - utilized in this model for host addressing since stateful DHCPv6 is - not universally supported for address acquisition. Stateful DHCPv6 - may be considering in the future as part of enabling support for IPv6 - prefix delegation [RFC3633]. - -4.3.2. IPv6 Configuration - - In order to make an IPv6 only experience possible Wi-Fi network - operators must ensure that UEs are able to reach all critical network - services over IPv6. Today, many host operating systems still prefer - querying DNS over IPv4. Additionally, widely deployed hosts do not - truly leverage a single common approach for IPv6 configuration. As - such the following should be expected to be available to support a - proper IPv6 only configuration: - - o RDNSS [RFC6106] is enabled by default and is expected to contain - one or more globally routable IPv6 addresses - - o Stateless DHCPv6 [RFC3315] is enabled by default and will - minimally transmit one or more DNS server IPv6 addresses. To - ensure the desired behavior is triggered IPv6 router - advertisements transmitted by the WLAN-GW will set the M flag to 0 - and the O flag to 1. + utilize on the shared provider managed network. -5. Operational Considerations +5. IPv6 Neighbourship Discovery Best Practices An operational consideration when using IPv6 address assignment using IPv6 SLAAC is that after the onboarding procedure the UE/subscriber will have a prefix with certain preferred and valid lifetimes. The - WLAN-GW extends these lifetimes by sending an unsolicited RA, the - applicable MaxRtrAdvInterval on the WLAN-GW MUST therefore be lower - than the preferred lifetime. As a consequence of this process is - that the WLAN-GW never knows when a UE/subscriber stops using - addresses from a prefix and additional procedures are required to - help the WLAN-GW to gain this information. When using stateful - DHCPv6 IA_NA for IPv6 UE/subscriber address assignment this - uncertainty on the WLAN-GW is not of impact due to the stateful - nature of DHCPv6 IA_NA address assignment. + First Hop Provider Router extends these lifetimes by sending an + unsolicited RA, the applicable MaxRtrAdvInterval on the WLAN-GW MUST + therefore be lower than the preferred lifetime. As a consequence of + this process is that the First Hop Router never knows when a UE/ + subscriber stops using addresses from a prefix and additional + procedures are required to help the First Hop Router to gain this + information. When using stateful DHCPv6 IA_NA for IPv6 UE/subscriber + address assignment this uncertainty on the First Hop Router is not of + impact due to the stateful nature of DHCPv6 IA_NA address assignment. Following is reference table of the key IPv6 router discovery and - neighbor discovery timers: + neighbor discovery timers for provider managed shared networks: o IPv6 Router Advertisement Interval = 300s o IPv6 Router LifeTime = 3600s o Reachable time = 30s o IPv6 Valid Lifetime = 3600s + o IPv6 Preferred Lifetime = 1800s o Retransmit timer = 0s The stateless nature of the UE/subscriber IPv6 SLAAC connectivity model provides value to make sure that the UE/subscriber context is - timely removed from the WLAN-GW to avoid ongoing resource depletion. - A possible solution is to use a subscriber inactivity timer which - after tracking a pre-defined (currently unspecified) # of minutes - deletes the subscriber context on the WLAN-GW. - - When using SLAAC the UE/subscriber the IP address assignment happens - without a WLAN-GW controlled state machine, and as result there is no - state-information on the WLAN-GW about actual IPv6 address usage. To - accomodate this the WLAN-GW can periodically perform a Subscriber - Host Connectivity Verification (i.e. periodically ping each IPv6 UE/ - subscriber from the WLAN-GW) to make sure that the subscriber table - on the WLAN-GW is correct and that the inactive UE/subscribers are - removed. + timely removed from the First Hop Router to avoid ongoing resource + depletion. A possible solution is to use a subscriber inactivity + timer which after tracking a pre-defined (currently unspecified) # of + minutes deletes the subscriber context on the First Hop Router. When employing stateless IPv6 address assignment a number of widely deployed operating systems will attempt to utilize RFC 4941 RFC4941 [RFC4941] temporary 'private' addresses. This can lead to the consequence that a UE has multiple /128 addresses from the same IPv6 - prefix. The WLAN-GW MUST be able to handle the presence and use of - multiple globally routable IPv6 addresses. - - When geo-localisation is of importance the WLAN-GW needs to have - information about the Access Point to which the UE/subscriber is - connected. In an environment using DHCPv6 IA_NA for IPv6 address - assignment this is achieved by having the AP insert an interface-id - RFC3315 [RFC3315] in the UE/subscriber DHCPv6 Solicit message. The - interface-id format expected is [ap-mac;ssid;[o-s]], e.g. - [00:11:22:33:44:55;example;o] (o stands for open, s for secure). - This way the service provider can learn both the AP-MAC (identifies - location) and the SSID (identifies service). When a service provider - uses SLAAC IPv6 address assignment it becomes harder for the service - provider to rely on this type of information and alternate solutions - have to be used to acquire the MAC address of the Access Point to - which the UE/subscriber is connected. A solution could be for the - WLAN-GW to support NSoGRE to harvest the Access-Point MAC address to - which the UE/subscriber is connected. - - For security purposes it will be important for the service provider - to have the capability on the WLAN-GW to have supported mechanics for - LI (Lawfull Intercept) and the installation of IPv6 filters per - subscriber. + prefix. The First Hop Provder Router MUST be able to handle the + presence and use of multiple globally routable IPv6 addresses. - For accounting purposes the WLAN-GW must be able to send usage - statistics per UE/subscriber using Radius attributes. + For accounting purposes the First Hop Provider Router must be able to + send usage statistics per UE/subscriber using Radius attributes. 6. Future work - o Support for IPv6 prefix delegation over Wi-Fi + o Informational draft regarding WLAN IPv6 Deployment technology + experiences roll-out 7. IANA Considerations No IANA considerations are defined at this time. 8. Security Considerations No Additional Security Considerations are made in this document. 9. Acknowledgements @@ -566,22 +292,22 @@ 10. References 10.1. Normative References [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 2003, . [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless - Address Autoconfiguration", RFC 4862, DOI 10.17487/ - RFC4862, September 2007, + Address Autoconfiguration", RFC 4862, + DOI 10.17487/RFC4862, September 2007, . [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, . [RFC6106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, "IPv6 Router Advertisement Options for DNS Configuration", RFC 6106, DOI 10.17487/RFC6106, November 2010, @@ -607,15 +333,15 @@ John Jason Brzozowski Comcast Cable 1701 John F. Kennedy Blvd. Philadelphia, PA USA Email: john_brzozowski@cable.comcast.com Gunter Van De Velde - Alcatel-Lucent + Nokia Antwerp Belgium - Email: gunter.van_de_velde@alcatel-lucent.com + Email: gunter.van_de_velde@nokia.com