Internet DRAFT - draft-ietf-netext-ani-location
draft-ietf-netext-ani-location
NETEXT WG R. Pazhyannur
Internet-Draft S. Speicher
Updates: 6757 (if approved) S. Gundavelli
Intended status: Standards Track Cisco Systems
Expires: September 23, 2015 J. Korhonen
Broadcom
J. Kaippallimalil
Huawei
March 22, 2015
Extensions to the PMIPv6 Access Network Identifier Option
draft-ietf-netext-ani-location-09.txt
Abstract
Access Network Identifier (ANI) Mobility option was introduced in
Access Network Identifier Option for Proxy Mobile IPv6 (RFC 6757).
This enables a Mobility Access Gateway (MAG) to convey identifiers
like network identifier, geolocation, and operator identifier. This
specification extends the Access Network Identifier mobility option
with sub options to carry civic location and 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 Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 23, 2015.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4
2.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
3. Protocol Extension . . . . . . . . . . . . . . . . . . . . . 4
3.1. Civic Location Sub-Option . . . . . . . . . . . . . . . . 4
3.2. MAG Group identifier Sub-Option . . . . . . . . . . . . . 5
3.3. ANI Update-Timer Sub-Option . . . . . . . . . . . . . . . 6
4. Protocol Considerations . . . . . . . . . . . . . . . . . . . 6
4.1. MAG Considerations . . . . . . . . . . . . . . . . . . . 6
4.2. LMA Considerations . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
Access Network Identifier (ANI) Option for Proxy Mobile IPv6
[RFC6757] introduced the Access Network Identifier (ANI) mobility
Option. This enabled a Mobility Access Gateway (MAG) to provide the
Network Identifier, geolocation, and Operator-Identifier sub options.
When the access network is WLAN, the Network Identifier sub option
may contain Service Set Identifier (SSID) and Basic Service Set
Identifier (BSSID) of the Access Point (AP), 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.
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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, particularly useful in WLAN deployments. In WLAN
deployments (especially indoor AP deployments), it is difficult to
provide Geo-spatial coordinates of APs. At the same time, for many
location based applications the civic location is sufficient. This
motivates the need for a 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
proxy for coarse location (such as 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
CAPWAP ([RFC5415], [RFC5416]), etc.
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. 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 ANI sub
option. Alternately, this draft 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 ANI sub option
except at the time of initial binding or in some cases it may care
about every AP transitions. The sub option allows LMA to tell the
MAG the desired update frequency. As always, mobility events or re-
registration events will update ANI sub options.The LMA can use 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. For example, 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.
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[RFC6757] provides ANI sub options to carry geolocation information.
In this document we provide additional sub options to carry 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 Terminology
2.1. 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 in RFC 2119 [RFC2119].
2.2. Terminology
All the mobility related terms used in this document are to be
interpreted as defined in [RFC5213] and [RFC5844].
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.
3. Protocol Extension
3.1. 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=IANA-1| ANI Length | Format | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| civic location ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Network-Identifier Sub-option
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ANI Type: <IANA-1>
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 in Section 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).
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./>.
3.2. 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, 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
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. (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=IANA-2| ANI Length | group identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: MAG group identifier Sub-option
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ANI Type: <IANA-2>
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 2 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=IANA-3| ANI Length | Update-Timer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Network-Identifier Sub-option
ANI Type: <IANA-3>
ANI Length: Total length of this sub option in octets, excluding the
ANI Type and ANI length fields is always 2.
Update-Timer: Update-Timer is a 16 bit unsigned integer. The unit
of time is seconds. 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 in Section 6.1 of
[RFC5213], is extended to store the access-network-related
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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 in Section 3.
o ANI Update-Timer Considerations: The MAG sets the Update-Timer
based on an exchange of timer values with the LMA. When the
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 Update-Timer sub option in PBA (in response to
sending the sub option in 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 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 the PBU sent to a 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
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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 in Section 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.
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 group identifier sub
options defined in this specification should not be altered by the
LMA. The LMA may change the value of the 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
This document requires the following IANA action.
o Action-1: This specification defines a new Access Network
Identifier sub option called civic location Sub-option. This
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mobility sub option is described in Section 3.1 and this sub
option can be carried in Access Network Identifier mobility
option. The type value <IANA-1> for this sub option needs to be
allocated from the registry "Access Network Information (ANI) Sub-
Option Type Values". RFC Editor: Please replace <IANA-1> in
Section 3.1 with the assigned value, and update this section
accordingly.
o Action-2: This specification defines a new Access Network
Identifier sub option called MAG group identifier Sub-option.
This mobility sub option is described in Section 3.2 and this sub
option can be carried in Access Network Identifier mobility
option. The type value <IANA-2> for this sub option needs to be
allocated from the registry "Access Network Information (ANI) Sub-
Option Type Values". RFC Editor: Please replace <IANA-2> in
Section 3.2 with the assigned value, and update this section
accordingly.
o Action-3: This specification defines a new Access Network
Identifier sub option called ANI Update-Timer Sub-option. This
sub option is described in Section 3.3 and this sub option can be
carried in Access Network Identifier mobility option. The type
value <IANA-3> for this sub option needs to be allocated from the
registry "Access Network Information (ANI) Sub-Option Type
Values". RFC Editor: Please replace <IANA-3> in Section 3.3 with
the assigned value, and update this section accordingly.
6. 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 from [RFC5213] and
[RFC6757], its security guidelines and does not require any
additional security considerations.
The civic location sub option carried in the Access Network
Information 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
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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 to 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.
7. Acknowledgements
This document benefited considerably from the numerous improvements
proposed by Kent Leung.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4776] Schulzrinne, H., "Dynamic Host Configuration Protocol
(DHCPv4 and DHCPv6) Option for Civic Addresses
Configuration Information", RFC 4776, November 2006.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC5844] Wakikawa, R. and S. Gundavelli, "IPv4 Support for Proxy
Mobile IPv6", RFC 5844, May 2010.
[RFC6757] Gundavelli, S., Korhonen, J., Grayson, M., Leung, K., and
R. Pazhyannur, "Access Network Identifier (ANI) Option for
Proxy Mobile IPv6", RFC 6757, October 2012.
[RFC7222] Liebsch, M., Seite, P., Yokota, H., Korhonen, J., and S.
Gundavelli, "Quality-of-Service Option for Proxy Mobile
IPv6", RFC 7222, May 2014.
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8.2. Informative References
[RFC5415] Calhoun, P., Montemurro, M., and D. Stanley, "Control And
Provisioning of Wireless Access Points (CAPWAP) Protocol
Specification", RFC 5415, March 2009.
[RFC5416] Calhoun, P., Montemurro, M., and D. Stanley, "Control and
Provisioning of Wireless Access Points (CAPWAP) Protocol
Binding for IEEE 802.11", RFC 5416, March 2009.
Authors' Addresses
Rajesh S. Pazhyannur
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
USA
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, CA 95134
USA
Email: sgundave@cisco.com
Jouni Korhonen
Broadcom
Porkkalankatu 24
Helsinki FIN-00180
Finland
Email: jouni.nospam@gmail.com
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John Kaippallimalil
Huawei
5340 Legacy Drive, Suite 175
Plano, Texas 75024
USA
Email: john.kaippallimalil@huawei.com
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