In this presentation I give an overview of IPv6 status in mobile networks.

1. Advances in IPv6
Mobile Access
John Loughney, Nokia
john.loughney@nokia.com
(with help from Teemu Savolainen, Nokia)
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2. Overview
Motivations for IPv6 in mobile networks
Main IPv6 Deployment options in mobile networks
Handset support for IPv6
Network support for IPv6
Key challenges
Practical advice
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3. Motivations
• 5.3 billion mobile subscribers, ITU-T figures for 2010.
• Large percentage are IP capable
−Trend toward Always-On applications (details next slide)
• LTE is happening now, will be soon doing voice over IP only.
• Operators run both a circuit switched and IP networks,
causing higher CAPEX and OPEX.
• In the future, services will migrate to IP.
• Carrier grade NATs are a misnomer.
• So the choice is between
−IPv4 with NAT frequent keep-alives & additional investments
−IPv6 and long lived connections
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4. NATs with keep alive messages
• IPv4 Mobile Devices are usually behind IPv4 NATs
−Always on application are becoming more prevalent
−Applications that want to be reachable need to send
periodic keep-alives to keep NAT state active
− Current NATs require keep-alives from 40 seconds to 5 minutes
− Need to implement for minimum (~30 seconds)
• Sending of NAT periodic keep-alive messages decreases mobile
device standby time by several days
• Not a problem for devices with power cords, but for mobile devices it
is a big problem
There should be NO The UDP inactivity timer in NATs causes the public
Client, Private
IPv4 address 1
NATs between the UDP port 6538 to be assigned to a different
terminal and the mobile, if the mobile does not send any data within
server! a certain amount of time, about every 40 seconds
…
Client, Private
IPv4 address 2 UDP port = 6538 Server, Public IPv4 address 3
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5. IPv6 Trial Checklist
• IPv6 enabled routers and switches
• IPv6 transit provider and peering
• IPv6 enabled hosts
• IPv6 enabled apps
• Address planning, address config, DNS
• Transition mechanism(s) selection
• Fallback planning
• Middlebox support (firewalls, proxies, etc.)
5 © Nokia 2011 Filename.pptx v. 0.1 YYYY-MM-DD Author Document ID [Edit via Insert > Header & Footer]
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6. Deployment approaches
Dual-stack approach is the most
customer-friendly solution for
transitioning to IPv6
Dual-stack is also the standard
approach (3GPP) and appears to be
the most favored approach
IPv6-only transition solution based on
protocol translation can cause service
discontinuity, and is only an option for
specific cases due to discrete reasons
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7. Details of dual-stack
3GPP release-8 introduced a new bearer
type: IPv4v6
IPv4 and IPv6 bearers can be used in
parallel when IPv4v6 is not supported
(since 3GPP release-99)
Various fallback scenarios are involved
that are not present with IPv4-only
devices, e.g. IPv4v6 -> IPv4 & IPv6
References: 3GPP release-8 23.060, 23.401
7 draft-ietf-v6ops-3gpp-eps
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8. Details of IPv6-only
Everything, including applications, MUST BE
IPv6 enabled – otherwise solutions such as
NAT46 on a host (aka BIH) may be needed
IPv6 is not always available: no support
on visited network, blocked on purpose
due lack of roaming agreements.. Fallback
support to IPv4-only mode is mandatory
This is pretty much the end-scenario
world is transitioning towards
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9. IPv6 impacts at all levels
Services & Content Google, YouTube, Akamai, Facebook, Bing, ...
Browsers, E-mail, IM, VoIP, Games, Utilities,
Applications Middleware entities like HTTP, ...
API Qt, Java, Posix, Symbian & other OS APIs, ...
Symbian, iOS, Android, Windows Phone, various
TCP/IP Stack flavors of Linux, Series 40, RIM,
Modem Renesas, Qualcomm, ST-E, GCT, Broadcom,
Icera (Nvidia), Marvell, Infineon, MediaTek, ...
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10. IPv6 on handsets
IPv6 support required at
different levels
IPv6 support on the applications
IPv6 support on APIs
IPv6 support on the connection manager
IPv6 support on the TCP/IP stack
IPv6 support on the modem
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11. Status of terminals
IPv6 support required
by the business
IPv6 support on the applications
IPv6 support on APIs
IPv6 support on the connection manager
IPv6 support on the TCP/IP stack
IPv6 support on the modem
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12. Phone support for IPv6
LG VL600
CDMA/LTE
dongle
Nokia 21M-02
2G/3G /3.5G USB
dongle
Android iPhone 4S Windows Phone 7 Symbian Nokia N9 Supports IPv6 and
Motorola Droid Bionic IPv6 for WLAN Mango Has supported IPv6 IPv6 add-on IPv4v6 PDP types
handset for Verizon only IPv4 only as no IPv6 since 2004, and used enables dual-
Reportedly has have yet on WP OS; in trials. Apps can use stack in 3G and
IPv6 for cellular. coming in Apollo IPv4 or IPv6 cellular WiFi accesses.
Samsung Nexus S access but not both
Has IPv6 for WLAN simultaneously. This
only. works normally when
using WiFi access.
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13. High level cellular requirements
• Dual-stack with single PDP (IPv6v4) is the most common solution
• Some network operators are considering dual-stack with parallel PDPs
(IPv6 & IPv4).
− It is required for a 3GPP fallback scenario.
• IPv6-only solution is also required by a few
• Other solutions are also queried and investigated, but not required yet
− PNAT, DS-Lite, DSMIP6, A+P & DS-Lite, 6rd.
• Configurability to single PDP (IPv4v6), parallel PDPs (IPv6 & IPv4), or only
IPv6
− OMA DM (operator configuration) for APN setting
• Gradual fallback in roaming and error cases for improved user experience
− IPv4v6 ► IPv4 & IPv6 ► IPv4 or IPv6
− IPv6 ► IPv4
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14. IPv6 status on mobile networks
• Closed IPv6 trials at least since 2003
• First commercial IPv6 deployments at 2010
− While many operators are conducting internal (lab) trials
• Public trials and some commercial deployments occurring
during 2011
− Even more operators are trialing
− Number of cellular IPv6 capable devices also increasing
• And things are getting even better for 2012 !
• But there are some gotchas
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15. Gotchas
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16. DNS server address discovery
• This has been a difficult topic in IETF...
• 3GPP cellular access
1. MUST take the address from PDP activation
2. Stateless DHCPv6 can be optionally supported
3. RA based approach can be supported but as not included in
3GPP specs, it is not something that can be depended upon.
• WiFi access
1. Stateless DHCPv6 is currently most widely available
2. RA based solution will probably be increasingly available as
standard RFC6106 exists (and e.g. RADVD supports this
hence Linux based routers can easily have this)
• In the dual-stack case, it is just fine to talk to the DNS server
over IPv4, but IPv6 should be preferred (as general principle)
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17. DNS query sending procedures
• Four possibilities for querying IPv4 and IPv6 addresses:
1) AAAA and A sequentially (Android, Maemo, Ubuntu)
2) A and AAAA sequentially (Windows 7, Symbian)
3) AAAA and A parallel
4) A and AAAA parallel (iOS, OS/X)
• Use of 3 or 4 avoids extra RTT in dual-stack networks
• The approach of sending A first is due to some legacy DNS
servers screwing up if they get AAAA followed by A.. So A first
may be slightly safer.
• Important to prefer IPv6 when both can be used
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18. ”Happy Eyeballs”
Endpoints issue DNS queries for AAAA and A resource Apps can improve the user experience by more
records and then attempts connections to IPv6 and aggressively making connections on IPv6 and IPv4
IPv4 addresses sequentially. If the IPv6 path is broken by using a variety of algorithms.
(or slow), it can take a long time before it falls back to In this approach, the application makes its
IPv4 resulting in delays from 20 seconds to several connection attempts more aggressively over both
minutes if the IPv6 path is broken. IPv6 and IPv4. Initially, the connection attempts are
made in order to provide a fast user experience
DNS
Dual-Stack Dual-Stack
host WLAN FW Internet
WWW
IPv6
1) Silent drop
IPv6
2) ICMPv6 no route
IPv6
3) ICMPv6 address unreachable
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19. IPv6 changes tethering significantly
Traditional dial-up style IPv4
tethering uses dedicated PDP
context for the dial-up IPv4 tethering solutions, often use
NAT and DHCP to allow sharing of
the same mobile connection with
Traditional dial-up is possible internal applications
also with IPv6
IPv6 does not use NATting, but instead Neighbor
Discovery Proxy ”bridging function” that does not
require explicit network support, or explicit and more
proper DHCPv6 Prefix Delegation as is defined in 3GPP
Release-10
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20. Bridging and DHCPv6 illustrated
”Bridging” with Neighbor Discovery DHCPv6 Prefix Delegation – support
Proxy – no explicit network support is included in 3GPP since Release-10
required!
PDN GW PDN GW & DHCPv6
server
PDP 2001:0db8:0:1::/64 PDP 2001:0db8:0:1::/64
Same Handset
f(”proxy”) prefix on (possibly with DHCPv6 server)
f(”router”)
both links Delegated e.g. 2001:0db8::/56
2001:0db8:0:C1::/64
2001:0db8:0:1::/64 2001:0db8:0:81::/64
WLAN WLAN WLAN
f(”router”)
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21. Illustration of basic WiFi Internet
offloading technologies
under study
WiFi access
Cellular operator’s
services
Rules via DHCPv6 DHCPv6 server
Routing Cellular access
rule DB Provisioning rules with OMA-DM
RFC4191
draft-ietf-mif-dhcpv6-route-option
Rules via IPv6 Router Advertisements Access Network Discovery
draft-ietf-mif-dns-server-selection and Selection Function
draft-korhonen-mif-ra-offload
3GPP 24.312 ANDSF (ANDSF)
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22. IPv6 standards are ready
Key specifications and standards are complete and
matured for product creation and deployment
Additional features and improvements are
actively researched, developed, and standardized. Nokia
participates, for example, to: IPv6 protocol maintenance,
Multi-Interface improvements, IP mobility solutions,
protocol translation topics, and Happy Eyeballs
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23. Recommendations
• Networks are getting deployed – use them
• Get a handset that supports IPv6 on both cellular and wifi
• Make sure you have apps that can speak both IPv4 and IPv6
−Don’t make address assumptions
−Address assignments are handled differently depending what
interface is used
• Make sure your apps implement a ‘happy eyeballs’
algorithm
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24. Additional reading
• Internet Protocol Version 6 (IPv6) for Some Second and Third
Generation Cellular Hosts
−http://tools.ietf.org/html/rfc3316
• IPv6 Node Requirements
−http://tools.ietf.org/html/rfc4294
• Happy Eyeballs: Success with Dual-Stack Hosts
−http://tools.ietf.org/html/draft-ietf-v6ops-happy-eyeballs-05
• Dual Stack Hosts Using "Bump-in-the-Host" (BIH)
−http://tools.ietf.org/html/draft-ietf-behave-v4v6-bih-06
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