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Internet Engineering Task Force (IETF)                     R. PazhyannurRequest for Comments: 7563                                   S. SpeicherUpdates:6757                                              S. GundavelliCategory: Standards Track                                  Cisco SystemsISSN: 2070-1721                                              J. Korhonen                                                    Broadcom Corporation                                                       J. Kaippallimalil                                                                  Huawei                                                               June 2015Extensions to the Proxy Mobile IPv6 (PMIPv6) Access Network IdentifierOptionAbstract   The Access Network Identifier (ANI) mobility option was introduced inRFC 6757, "Access Network Identifier (ANI) Option for Proxy Mobile   IPv6".  This enables a Mobile Access Gateway (MAG) to convey   identifiers like the network identifier, geolocation, and operator   identifier.  This specification extends the Access Network Identifier   mobility option with sub-options to carry the civic location and the   MAG group identifier.  This specification also defines an ANI Update-   Timer sub-option that determines when and how often the ANI option   will be updated.Status of This Memo   This is an Internet Standards Track document.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Further information on   Internet Standards is available inSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc7563.Pazhyannur, et al.           Standards Track                    [Page 1]

RFC 7563                    Extensions to ANI                  June 2015Copyright Notice   Copyright (c) 2015 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 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 Contents1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .32.  Conventions and Terminology . . . . . . . . . . . . . . . . .42.1.  Conventions . . . . . . . . . . . . . . . . . . . . . . .42.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .43.  Protocol Extension  . . . . . . . . . . . . . . . . . . . . .53.1.  Civic-Location Sub-Option . . . . . . . . . . . . . . . .53.2.  MAG-Group-Identifier Sub-Option . . . . . . . . . . . . .63.3.  ANI Update-Timer Sub-Option . . . . . . . . . . . . . . .64.  Protocol Considerations . . . . . . . . . . . . . . . . . . .74.1.  MAG Considerations  . . . . . . . . . . . . . . . . . . .74.2.  LMA Considerations  . . . . . . . . . . . . . . . . . . .85.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .96.  Security Considerations . . . . . . . . . . . . . . . . . . .107.  References  . . . . . . . . . . . . . . . . . . . . . . . . .117.1.  Normative References  . . . . . . . . . . . . . . . . . .117.2.  Informative References  . . . . . . . . . . . . . . . . .11   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .12   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .12Pazhyannur, et al.           Standards Track                    [Page 2]

RFC 7563                    Extensions to ANI                  June 20151.  Introduction   "Access Network Identifier (ANI) Option for Proxy Mobile IPv6"   [RFC6757] introduced the ANI mobility option.  This enabled a Mobile   Access Gateway (MAG) to provide the Network-Identifier, Geo-Location,   and Operator-Identifier sub-options.  When the access network is   WLAN, the Network-Identifier sub-option may contain the Service Set   Identifier (SSID) and the Basic Service Set Identifier (BSSID) of the   Access Point (AP) and the geolocation of the AP, and the Operator-   Identifier may contain the realm of the operator managing the WLAN.   The MAG sends the above information to the Local Mobility Anchor   (LMA).  The LMA may use this information to determine access-network-   specific policies (in terms of Quality of Service (QoS), Deep Packet   Inspection (DPI), etc.).  Further, the LMA may make this information   available to location-based applications.   While the above mentioned sub-options provide a rich set of   information, in this document we describe the need for extending the   ANI sub-options that are particularly useful in WLAN deployments.  In   WLAN deployments (especially indoor AP deployments), it is difficult   to provide geospatial coordinates of APs.  At the same time, for many   location-based applications the civic location is sufficient.  This   motivates the need for an ANI Civic-Location sub-option.  In many   deployments, operators tend to create groups of APs into "AP-Groups".   These groups have a group identifier.  The group identifier is used   as a proxy for coarse location (such as the floor of a building or a   small building).  The group identifier may also be used to provide a   common policy (e.g., QoS, charging, DPI) for all APs in that group.   This specification provides a sub-option for the MAG to convey a   group identifier to the LMA.  The provisioning of the group   identifier is outside the scope of this specification and is   typically done via a configuration mechanism such as CLI (Command-   line Interface) or via Control and Provisioning of Wireless Access   Points (CAPWAP) [RFC5415] [RFC5416].   This document also provides a new sub-option that determines how   often the MAG will update the ANI.  In typical deployments, it is   expected that the MAG will update the ANI as soon as it changes.   This is certainly true when the MAG is co-located with the AP.  When   a client roams from one AP to another AP, the MAG on the roamed (or   sometimes referred to as the target) AP will provide the new ANI (for   example, the network identifier and geolocation of the new AP).   However, if the MAG is co-located with an Access Controller (also   known as Wireless LAN Controller (WLC)), then a client roaming from   one AP to another AP does not necessarily perform an ANI update.  The   WLC handles client mobility between APs and as a result, intra-WLC   mobility is hidden from the LMA.Pazhyannur, et al.           Standards Track                    [Page 3]

RFC 7563                    Extensions to ANI                  June 2015   In such deployments, the information conveyed in the ANI sub-options   (e.g., location) becomes stale and is only refreshed at the time of   lifetime expiry.  The MAG could deal with this by sending a Proxy   Binding Update (PBU) whenever a client moves between APs just for the   purpose of updating the ANI sub-option.  Alternately, this document   allows the LMA to determine how often it wants to know about the   changes in the ANI sub-option; for example, in some cases the LMA may   not care about the ANI sub-option except at the time of initial   binding, or in some cases it may care about every AP transition.  The   sub-option allows the LMA to tell the MAG the desired update   frequency.  As always, mobility events or re-registration events will   update the ANI sub-options.  The LMA can use the ANI Update-Timer   option to set the maximum frequency at which it wants to receive ANI   updates.  This is particularly useful in environments where a MAG   covers a large number of Wi-Fi APs and there is high client mobility   between the APs; for example, in a stadium Wi-Fi deployment, if a LMA   does not want ANI updates any more often than 100 seconds, then it   can propose 100 seconds as the value for ANI Update-Timer.   [RFC6757] provides ANI sub-options to carry geolocation information.   In this document, we provide additional sub-options to carry the   civic location and group identifier.  This document also defines an   ANI sub-option to enable a MAG to communicate how often the MAG will   update the ANI information.2.  Conventions and Terminology2.1.  Conventions   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this   document are to be interpreted as described inRFC 2119 [RFC2119].2.2.  Terminology   All of the mobility-related terms used in this document are to be   interpreted as defined in [RFC5213] and [RFC5844].  In this document,   Civic Location is defined as follows.      Civic Location: There are two common ways to identify the location      of an object, either through geospatial coordinates or by so-      called civic addresses.  Geospatial coordinates indicate      longitude, latitude, and altitude, while civic addresses indicate      a street address or sometimes the location within a building (such      as a room number).  Civic location refers to the civic address.Pazhyannur, et al.           Standards Track                    [Page 4]

RFC 7563                    Extensions to ANI                  June 20153.  Protocol Extension3.1.  Civic-Location Sub-Option   The Civic-Location is a mobility sub-option carried in the Access   Network Identifier option defined in [RFC6757].  This sub-option   carries the civic location information of the mobile node as known to   the MAG.  The format of this option is defined below.    0                   1                   2                   3    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |ANI Type=4     |  ANI Length   |   Format      | Reserved      |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |            civic location                                     ~   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                    Figure 1: Civic-Location Sub-Option   ANI Type:  4   ANI Length:  Total length of this sub-option in octets, excluding the      ANI Type and ANI Length fields.   Format:  This specifies the encoding format of the civic location.      The value 0 is defined in this specification as described below.      The remaining values (1 through 255) are reserved.            0: This value denotes Binary Encoding.  The location format            is based on the encoding format defined inSection 3.1 of            [RFC4776], whereby the first 3 octets are not put into the            civic location field (i.e., the code for the DHCP option,            the length of the DHCP option, and the 'what' element are            not included).  What is included is the two-octet country            code field, followed by one or more civic address elements.            The country-code is a two-letter ISO 3166 country code in            capital ASCII letters, e.g., US.  The structure of the civic            address elements that follow the country code field is as            defined inSection 3.3 of [RFC4776].   Reserved:  This MUST be set to zero when sending and ignored when      received.   civic location:  This field will contain the civic location.  The      format (encoding) type is specified in the format field of this      sub-option.  Note that the length SHALL NOT exceed 253 bytes.Pazhyannur, et al.           Standards Track                    [Page 5]

RFC 7563                    Extensions to ANI                  June 20153.2.  MAG-Group-Identifier Sub-Option   The MAG group identifier is a mobility sub-option carried in the   Access Network Identifier option defined in [RFC6757].  The MAG group   identifier identifies the group affiliation of the MAG within that   Proxy Mobile IPv6 domain.  The group identifier is not assumed to be   globally unique across different network operators.  However, the   group identifier should be unique within an operator network.  In   domains spanning multiple operators, it is recommended that the   Operator-Identifier sub-option (defined in [RFC6757]) be used in   addition to the MAG-Group-Identifier sub-option to ensure uniqueness.   When the MAG is configured with a group identifier, the MAG should   send its group identifier in the PBU.  Note that the configuration of   this identifier is outside the scope of this specification; the usage   of the identifier by the LMA is left to implementation.  The format   of this sub-option is defined below.    0                   1                   2                   3    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |ANI Type=5     |  ANI Length   |  group identifier             |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                 Figure 2: MAG-Group-Identifier Sub-Option   ANI Type:  5   ANI Length:  Total length of this sub-option in octets, excluding the      ANI Type and ANI Length fields.  The value is always 2.   group identifier:  This is a 3-octet unsigned integer value assigned      to a group of MAGs.3.3.  ANI Update-Timer Sub-Option   The ANI Update-Timer is a mobility sub-option carried in the ANI   option defined in [RFC6757].Section 4 describes how the MAG and LMA   use this sub-option.    0                   1                   2                   3    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |ANI Type=6     |  ANI Length   |       Update-Timer            |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                   Figure 3: ANI Update-Timer Sub-OptionPazhyannur, et al.           Standards Track                    [Page 6]

RFC 7563                    Extensions to ANI                  June 2015   ANI Type:  6   ANI Length:  Total length of this sub-option in octets, excluding the      ANI Type and ANI Length fields.  The value is always 2.   Update-Timer:  Update-Timer is a 16-bit unsigned integer.  The unit      of time is 4 seconds (time unit of 4 seconds ensures consistency      with the time units for the binding lifetime).  A value of 0      indicates that the MAG will send an updated ANI mobility option as      soon as it discovers a change in ANI values.  A non-zero value      indicates that the MAG may not send ANI values immediately after      they have changed but rather send ANI updates when the      Update-Timer expires.4.  Protocol Considerations   The following considerations apply to the LMA and the MAG.4.1.  MAG Considerations   o  The conceptual Binding Update List entry data structure maintained      by the mobile access gateway, described inSection 6.1 of      [RFC5213], is extended to store the access-network-related      information elements associated with the current session.      Specifically, the following parameters are defined:      *  civic location      *  MAG group identifier      *  ANI Update-Timer   o  If the mobile access gateway is configured to support the Access      Network Information sub-options defined in this specification, it      includes this option with the specific sub-options in all PBU      messages (including PBUs for lifetime extension and for      deregistration) that it sends to the LMA.  The Access Network      Information option is constructed as specified inSection 3.   o  ANI Update-Timer Considerations: The MAG sets the Update-Timer      based on an exchange of timer values with the LMA.  When the ANI      Update-Timer sub-option is carried in a PBU, it is considered as a      proposed value for the Update-Timer.  The LMA may change the value      of the Update-Timer received in the PBU.  When the LMA-provided      value for the Update-Timer is different than what is sent by the      MAG, the MAG should use the LMA-provided value.  If the MAG does      not receive an ANI Update-Timer sub-option in the Proxy Binding      Acknowledgement (PBA) (in response to sending the sub-option inPazhyannur, et al.           Standards Track                    [Page 7]

RFC 7563                    Extensions to ANI                  June 2015      the PBU), then MAG behavior is in accordance to [RFC6757].  When      ANI parameters of a mobility session change, the MAG checks      whether the Update-Timer has expired.  If the Update-Timer has      expired, the MAG sends a PBU with the ANI option.  The ANI option      reflects the updated access network parameters for that mobility      session.  If the Update-Timer has not expired, the MAG does not      send a PBU.  When the Update-Timer for a mobility session expires,      the MAG checks whether the ANI parameters have changed.  If the      parameters have changed from the last reported values, the MAG      sends a PBU with an ANI option.  If the parameters have not      changed, the MAG does not send a PBU (and the Update-Timer remains      expired).  Note that the MAG may send a PBU even before the      Update-Timer expires.  This could be, for example, to initiate a      QoS service request to the LMA (see [RFC7222]).  In such cases,      the MAG must reset the Update-Timer when it sends a PBU.   o  If the mobile access gateway had any of the Access Network      Information mobility options included in the PBU sent to an LMA,      then the PBA received from the LMA should contain the Access      Network Information mobility option with the specific sub-options.      If the mobile access gateway receives a PBA with a successful      Status Value but without an Access Network Information mobility      option, then the mobile access gateway may log the event and,      based on its local policy, even proceed to terminate the mobility      session.  In this case, the mobile access gateway knows the LMA      does not understand the Access Network Information mobility      option.4.2.  LMA Considerations   o  The conceptual Binding Cache entry data structure maintained by      the LMA, described inSection 5.1 of [RFC5213], is extended to      store the access-network-related information elements associated      with the current session.  Specifically, the following parameters      are defined:      *  civic location      *  MAG group identifier      *  ANI Update-Timer   o  On receiving a PBU message from a MAG with the ANI option, the LMA      must process the option and update the corresponding fields in the      Binding Cache entry.  If the option is not understood by that LMA      implementation, it will skip the option and process the PBU      without these options.Pazhyannur, et al.           Standards Track                    [Page 8]

RFC 7563                    Extensions to ANI                  June 2015   o  If the received PBU message does not include the Access Network      Information option, then the mobility session associated with that      PBU is updated to remove any access network information elements.   o  If the LMA understands/supports the Access Network Identifier      mobility sub-options defined in this specification, then the LMA      echoes the Access Network Identifier mobility option with the      specific sub-option(s) that it accepted back to the mobile access      gateway in a PBA.  The Civic-Location and MAG-Group-Identifier      sub-options defined in this specification should not be altered by      the LMA.  The LMA may change the value of the ANI Update-Timer      sub-option.  It may choose to either echo the same value or      increase or decrease the timer value.  For example, if the LMA      does not want to receive frequent updates (as implied by the timer      value), it may choose to increase the value.  Similarly, if the      LMA needs to receive ANI updates as soon as possible, then it may      set the value to zero (0) in the PBA.5.  IANA Considerations   IANA has registered the values described below.   o  This specification defines a new Access Network Identifier sub-      option called the Civic-Location sub-option.  This mobility sub-      option is described inSection 3.1 and this sub-option can be      carried in the Access Network Identifier mobility option.  The      type value <4> has been allocated from the registry "Access      Network Information (ANI) Sub-Option Type Values".   o  This specification defines a new Access Network Identifier sub-      option called the MAG-Group-Identifier sub-option.  This mobility      sub-option is described inSection 3.2 and this sub-option can be      carried in Access Network Identifier mobility option.  The type      value <5> has been allocated from the registry "Access Network      Information (ANI) Sub-Option Type Values".   o  This specification defines a new Access Network Identifier sub-      option called the ANI Update-Timer sub-option.  This sub-option is      described inSection 3.3 and this sub-option can be carried in the      Access Network Identifier mobility option.  The type value <6> has      been allocated from the registry "Access Network Information (ANI)      Sub-Option Type Values".Pazhyannur, et al.           Standards Track                    [Page 9]

RFC 7563                    Extensions to ANI                  June 20156.  Security Considerations   The Civic-Location sub-option defined in this specification is   carried in the Access Network Identifier option defined in [RFC6757].   This sub-option is carried in PBU and PBA messages.  This sub-option   is carried like any other Access Network Identifier sub-option as   defined in [RFC6757].  Therefore, it inherits its security guidelines   from [RFC5213] and [RFC6757] and does not require any additional   security considerations.   The Civic-Location sub-option exposes the civic location of the   network to which the mobile node is attached.  This information is   considered to be very sensitive, so care must be taken to secure the   Proxy Mobile IPv6 signaling messages when carrying this sub-option.   The base Proxy Mobile IPv6 specification [RFC5213] specifies the use   of IPsec for securing the signaling messages, and those mechanisms   can be enabled for protecting this information.  Operators can   potentially apply IPsec Encapsulating Security Payload (ESP) with   confidentiality and integrity protection for protecting the location   information.  The other way to protect the sensitive location   information of network users is of course to not send it in the first   place.  Users of the Civic-Location sub-option should provision   location values with the highest possible level of granularity, e.g.,   to the province or city level rather than provisioning specific   addresses.   Access-network-specific information elements that the mobile access   gateway sends may have been dynamically learned over DHCP or using   other protocols.  If proper security mechanisms are not in place, the   exchanged information between the MAG and LMA may be compromised.   This situation may result in incorrect service policy enforcement at   the LMA and impact other services that depend on this access network   information.  This threat can be mitigated by ensuring the   communication path between the mobile access gateway and the access   points is properly secured by the use of IPsec, Transport Layer   Security (TLS), or other security protocols.Pazhyannur, et al.           Standards Track                   [Page 10]

RFC 7563                    Extensions to ANI                  June 20157.  References7.1.  Normative References   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119,              DOI 10.17487/RFC2119, March 1997,              <http://www.rfc-editor.org/info/rfc2119>.   [RFC4776]  Schulzrinne, H., "Dynamic Host Configuration Protocol              (DHCPv4 and DHCPv6) Option for Civic Addresses              Configuration Information",RFC 4776,              DOI 10.17487/RFC4776, November 2006,              <http://www.rfc-editor.org/info/rfc4776>.   [RFC5213]  Gundavelli, S., Ed., Leung, K., Devarapalli, V.,              Chowdhury, K., and B. Patil, "Proxy Mobile IPv6",RFC 5213, DOI 10.17487/RFC5213, August 2008,              <http://www.rfc-editor.org/info/rfc5213>.   [RFC5844]  Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy              Mobile IPv6",RFC 5844, DOI 10.17487/RFC5844, May 2010,              <http://www.rfc-editor.org/info/rfc5844>.   [RFC6757]  Gundavelli, S., Ed., Korhonen, J., Ed., Grayson, M.,              Leung, K., and R. Pazhyannur, "Access Network Identifier              (ANI) Option for Proxy Mobile IPv6",RFC 6757,              DOI 10.17487/RFC6757, October 2012,              <http://www.rfc-editor.org/info/rfc6757>.   [RFC7222]  Liebsch, M., Seite, P., Yokota, H., Korhonen, J., and S.              Gundavelli, "Quality-of-Service Option for Proxy Mobile              IPv6",RFC 7222, DOI 10.17487/RFC7222, May 2014,              <http://www.rfc-editor.org/info/rfc7222>.7.2.  Informative References   [RFC5415]  Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley,              Ed., "Control And Provisioning of Wireless Access Points              (CAPWAP) Protocol Specification",RFC 5415,              DOI 10.17487/RFC5415, March 2009,              <http://www.rfc-editor.org/info/rfc5415>.   [RFC5416]  Calhoun, P., Ed., Montemurro, M., Ed., and D. Stanley,              Ed., "Control and Provisioning of Wireless Access Points              (CAPWAP) Protocol Binding for IEEE 802.11",RFC 5416,              DOI 10.17487/RFC5416, March 2009,              <http://www.rfc-editor.org/info/rfc5416>.Pazhyannur, et al.           Standards Track                   [Page 11]

RFC 7563                    Extensions to ANI                  June 2015Acknowledgements   This document benefited considerably from the numerous improvements   proposed by Kent Leung.Authors' Addresses   Rajesh S. Pazhyannur   Cisco Systems   170 West Tasman Drive   San Jose, California  95134   United States   EMail: rpazhyan@cisco.com   Sebastian Speicher   Cisco Systems   Richtistrasse 7   Wallisellen, Zurich  8304   Switzerland   EMail: sespeich@cisco.com   Sri Gundavelli   Cisco Systems   170 West Tasman Drive   San Jose, California  95134   United States   EMail: sgundave@cisco.com   Jouni Korhonen   Broadcom Corporation   3151 Zanker Road   San Jose, California  95134   United States   EMail: jouni.nospam@gmail.com   John Kaippallimalil   Huawei   5340 Legacy Drive, Suite 175   Plano, Texas  75024   United States   EMail: john.kaippallimalil@huawei.comPazhyannur, et al.           Standards Track                   [Page 12]