draft-ietf-v6ops-ipv6-roaming-analysis-06.txt   draft-ietf-v6ops-ipv6-roaming-analysis-07.txt 
Network Working Group G. Chen Network Working Group G. Chen
Internet-Draft H. Deng Internet-Draft H. Deng
Intended status: Informational China Mobile Intended status: Informational China Mobile
Expires: April 15, 2015 D. Michaud Expires: April 22, 2015 D. Michaud
Rogers Communications Rogers Communications
J. Korhonen J. Korhonen
Broadcom Broadcom
M. Boucadair M. Boucadair
France Telecom France Telecom
A. Vizdal A. Vizdal
Deutsche Telekom AG Deutsche Telekom AG
October 12, 2014 October 19, 2014
IPv6 Roaming Behavior Analysis Analysis of Failure Cases in IPv6 Roaming Scenarios
draft-ietf-v6ops-ipv6-roaming-analysis-06 draft-ietf-v6ops-ipv6-roaming-analysis-07
Abstract Abstract
This document identifies a set of failure cases that may be This document identifies a set of failure cases that may be
encountered by IPv6-enabled mobile customers in roaming scenarios. encountered by IPv6-enabled mobile customers in roaming scenarios.
The analysis reveals that the failure causes include improper The analysis reveals that the failure causes include improper
configurations, incomplete functionality support in equipment, and configurations, incomplete functionality support in equipment, and
inconsistent IPv6 deployment strategies between the home and the inconsistent IPv6 deployment strategies between the home and the
visited networks. visited networks.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 15, 2015. This Internet-Draft will expire on April 22, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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o The Public Land Mobile Network (PLMN) is a network that is o The Public Land Mobile Network (PLMN) is a network that is
operated by a single administrative entity. A PLMN (and therefore operated by a single administrative entity. A PLMN (and therefore
also an operator) is identified by the Mobile Country Code (MCC) also an operator) is identified by the Mobile Country Code (MCC)
and the Mobile Network Code (MNC). Each (telecommunications) and the Mobile Network Code (MNC). Each (telecommunications)
operator providing mobile services has its own PLMN [RFC6459]. operator providing mobile services has its own PLMN [RFC6459].
o The Home Location Register (HLR) is a pre-Release-5 database (but o The Home Location Register (HLR) is a pre-Release-5 database (but
is also used in Release-5 and later networks in real deployments) is also used in Release-5 and later networks in real deployments)
that contains subscriber data and information related to call that contains subscriber data and information related to call
routing. All subscribers of an operator, and the subscribers' routing. All subscribers of an operator and the subscribers'
enabled services, are provisioned in the HLR [RFC6459]. enabled services are provisioned in the HLR [RFC6459].
o The Home Subscriber Server (HSS) is a database for a given o The Home Subscriber Server (HSS) is a database for a given
subscriber and was introduced in 3GPP Release-5. It is the entity subscriber and was introduced in 3GPP Release-5. It is the entity
containing the subscription-related information to support the containing the subscription-related information to support the
network entities actually handling calls/sessions [RFC6459]. network entities actually handling calls/sessions [RFC6459].
"HLR/HSS" is used collectively for the subscriber database unless "HLR/HSS" is used collectively for the subscriber database unless
referring to the failure case related to General Packet Radio Service referring to the failure case related to General Packet Radio Service
(GPRS) Subscriber data from the HLR. (GPRS) Subscriber data from the HLR.
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464xlat[RFC6877] is proposed to address the IPv4 compatibility issue 464xlat[RFC6877] is proposed to address the IPv4 compatibility issue
in an IPv6-only connectivity environment. The customer-side in an IPv6-only connectivity environment. The customer-side
translator (CLAT) function on a mobile device is likely used in translator (CLAT) function on a mobile device is likely used in
conjunction with a PDP/PDN IPv6 type request and cooperates with a conjunction with a PDP/PDN IPv6 type request and cooperates with a
remote NAT64 [RFC6146] device. remote NAT64 [RFC6146] device.
464xlat may use the mechanism defined in [RFC7050] or [RFC7225] to 464xlat may use the mechanism defined in [RFC7050] or [RFC7225] to
detect the presence of NAT64 devices and to learn the IPv6 prefix detect the presence of NAT64 devices and to learn the IPv6 prefix
used for protocol translation[RFC6052]. used for protocol translation[RFC6052].
In local breakout approach, when a UE with the 464xlat function In the local breakout approach, when a UE with the 464xlat function
roaming to an IPv6 visited network may encounter various situations. roaming on an IPv6 visited network may encounter various situations.
For example, the visited network may not deploy DNS64 [RFC6147] but For example, the visited network may not deploy DNS64 [RFC6147] but
only NAT64, CLAT may not be able to discover the provider-side only NAT64, CLAT may not be able to discover the provider-side
translator (PLAT) translation IPv6 prefix used as a destination of translator (PLAT) translation IPv6 prefix used as a destination of
the PLAT. If the visited network doesn't deploy NAT64 and DNS64, the PLAT. If the visited network doesn't deploy NAT64 and DNS64,
464xlat can't perform successfully due to the lack of PLAT 464xlat can't perform successfully due to the lack of PLAT
collaboration. Even in the case of the presence of NAT64 and DNS64, collaboration. Even in the case of the presence of NAT64 and DNS64,
pre-configured PLAT-side IPv6 prefix in the CLAT may cause the pre-configured PLAT-side IPv6 prefix in the CLAT may cause the
failure because it can't match the PLAT translation. failure because it can't match the PLAT translation.
Considering the various network's situations, operators may turn off Considering the various network's situations, operators may turn off
the local breakout and use the home routed mode to perform 464xlat. local breakout and use the home routed mode to perform 464xlat.
Alternatively, UE may support the different roaming profile Alternatively, UE may support the different roaming profile
configurations to adopt 464xlat in the home networks and use configurations to adopt 464xlat in the home networks and use
IPv4-only in the visited networks. IPv4-only in the visited networks.
6. HLR/HSS User Profile Setting 6. HLR/HSS User Profile Setting
A proper user profile configuration would provide a deterministic A proper user profile configuration would provide a deterministic
outcome to the PDP/PDN creation stage where dual-stack, IPv4-only and outcome to the PDP/PDN creation stage where dual-stack, IPv4-only and
IPv6-only connectivity requests may come from devices. The HLR/HSS IPv6-only connectivity requests may come from devices. The HLR/HSS
may have to apply extra logic (not standardized by 3GPP) to achieve may have to apply extra logic (not standardized by 3GPP) to achieve
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Several failure cases have been discussed in this document. It has Several failure cases have been discussed in this document. It has
been illustrated that the major problems happen at three stages, been illustrated that the major problems happen at three stages,
i.e., the initial network attachment, the PDP/PDN creation and i.e., the initial network attachment, the PDP/PDN creation and
service requests. service requests.
In the network attachment stage, PDP/PDN type IPv4v6 is the major In the network attachment stage, PDP/PDN type IPv4v6 is the major
concern to the visited pre-Release 9 SGSN. 3GPP didn't specify PDP/ concern to the visited pre-Release 9 SGSN. 3GPP didn't specify PDP/
PDN type IPv4v6 in the earlier releases. That PDP/PDN type is PDN type IPv4v6 in the earlier releases. That PDP/PDN type is
supported in new-built EPS network, but isn't supported well in the supported in new-built EPS network, but isn't supported well in the
third generation network. The situations may cause the roaming third generation network. Visited SGSNs may discard the subscriber's
issues of declining the attach request of dual-stack subscribers. attach requests because the SGSN is unable to correctly process PDP/
Operators may have to adopt temporary solutions unless all the PDN type IPv4v6. Operators may have to adopt temporary solutions
interworking nodes (i.e., the SGSN) in the visited network have been unless all the interworking nodes (i.e., the SGSN) in the visited
upgraded to support the ext-PDP-Type feature. network have been upgraded to support the ext-PDP-Type feature.
In the PDP/PDN creation stage, PDP/PDN types IPv4v6 and IPv6 support In the PDP/PDN creation stage, PDP/PDN types IPv4v6 and IPv6 support
on the visited SGSN is the major concern. It has been observed that on the visited SGSN is the major concern. It has been observed that
IPv6 single stack with the home routed mode is a viable approach to IPv6 single stack with the home routed mode is a viable approach to
deploy IPv6. It is desirable that the visited SGSN could enable IPv6 deploy IPv6. It is desirable that the visited SGSN could enable IPv6
on the user plane by default. For support of the PDP/PDN type on the user plane by default. For support of the PDP/PDN type
IPv4v6, it is suggested to set the DAF. As a complementary function, IPv4v6, it is suggested to set the DAF. As a complementary function,
the implementation of roaming APN configuration is useful to the implementation of roaming APN configuration is useful to
accommodate the visited network. However, it should consider roaming accommodate the visited network. However, it should consider roaming
architecture and permitted PDP/PDN type to make proper setting on the architecture and permitted PDP/PDN type to make proper setting on the
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local breakout case. The visited network may not be able to satisfy local breakout case. The visited network may not be able to satisfy
the requested capability from applications or UEs. Operators may the requested capability from applications or UEs. Operators may
consider using home routed mode to avoid these problems. Several consider using home routed mode to avoid these problems. Several
solutions either in the network side or mobile device side can also solutions either in the network side or mobile device side can also
help to address the issue. For example, help to address the issue. For example,
o 464xlat could help IPv4 applications access IPv6 visited networks. o 464xlat could help IPv4 applications access IPv6 visited networks.
o Networks can deploy an AAA server to coordinate the mobile device o Networks can deploy an AAA server to coordinate the mobile device
capability. Once the GGSN/PGW receives the session creation capability. Once the GGSN/PGW receives the session creation
request, it will initiate an Access-Request to AAA server in the request, it will initiate an Access-Request to an AAA server in
home network via the RADIUS protocol. The Access-Request contains the home network via the RADIUS protocol. The Access-Request
subscriber and visited network information, e.g., PDP/PDN Type, contains subscriber and visited network information, e.g., PDP/PDN
International Mobile Equipment Id (IMEI), Software Version (SV) Type, International Mobile Equipment Id (IMEI), Software Version
and visited SGSN/MME location code, etc. The AAA server could (SV) and visited SGSN/MME location code, etc. The AAA server
take mobile device capability and combine it with the visited could take mobile device capability and combine it with the
network information to ultimately determine the type of session to visited network information to ultimately determine the type of
be created, i.e., IPv4, IPv6 or IPv4v6. session to be created, i.e., IPv4, IPv6 or IPv4v6.
8. IANA Considerations 8. IANA Considerations
This document makes no request of IANA. This document makes no request of IANA.
9. Security Considerations 9. Security Considerations
Although this document defines neither a new architecture nor a new Although this document defines neither a new architecture nor a new
protocol, the reader is encouraged to refer to [RFC6459] for a protocol, the reader is encouraged to refer to [RFC6459] for a
generic discussion on IPv6-related security considerations. generic discussion on IPv6-related security considerations.
 End of changes. 9 change blocks. 
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