"Applying IPv6 to LTE Networks" by Deoknyong Ko. A presentation given at the APNIC 40 Internet Mobility Nexus session on Tue 8 Sep 2015.

1. 2015.9.8
Deoknyong Ko (engineer@sk.com)
New Connectivity TF
Network Technology R&D Center
SKtelecom

2. What’s the first things
that pops into your mind
when you hear the word, Korea?

3. What’s the first things
that pops into your mind
when you hear the word, Korea?

4. Which country invented the Internet
for the first time in the world ?
Which country was next ?

5. Which country invented the Mobile IPv6 Internet
for the first time in the world ?
Which country was next ?

6. What’s the first things
that pops into your mind
when you hear the word, Korea?

7. ※ The Market Share of Mobile
Subscribers in Korea
SKtelecom
50.5%
KT
LG U+
Wired Broadband Mobile Platform Semiconductor

8. Background
IPv6 Transition Schemes
Contents
FAQ

9. Background
IPv6 Transition Schemes
Contents
FAQ

10. Korean Status in The Past
France
United States
Japan
Germany
Romania

11. Korean Government’s Encourage
Subject Company Networks Date
Operator
SKtelecom On Commercial '14.9.25
SKbroadband On Field Trial ’12.5.29
KT Preparing
LGU+
On Commercial
(Only Voice)
Portal
Naver Preparing
Daum On Commercial '14.9.25
Nate Preparing

12. Summary of Applying IPv6
Subject Purpose Networks
Transition
Scheme
Date Subscribers
Wired Field Trial HFC, G-PON Dual Stack ’12.5.29 1 thousand
Wireless Commercial LTE Only IPv6 '14.9.25 670 thousands
IPv4
Networks
Dual Stack
(IPv4/IPv6)
Only IPv6
Networks
IPv4
Networks
※ Subscribers by Jan. 2015
Only IPv6
Networks

13. Why Did SKT Decide to
Adopt IPv6 ?

14. Why Did SKT Decide to
Adopt IPv6 ?
CapEx for NAT equipment
※ Reference: http://www.google.com/intl/en/IPv6/index.html
∙ LTE device has 2 different IPv4 addresses by default in SKT.
∙ The number of connected device could exponentially increase.

15. Difficult to operate duplicated networks
Why Did SKT Decide to
Adopt IPv6 ?
Network
A
Network
B
Network
A
Network
B
PDN-GW#1
Public
Network
PDN-GW#2

16. Korean government’s encouragement
Why Did SKT Decide to
Adopt IPv6 ?
※ The statistics of IPv6 users. (http://6lab.cisco.com/stats)
United States
Norway
Germany
Belgium

17. Which Networks
to be migrated IPv6?
Applying IPv6 to only primary networks.
Legacy network will be replaced to LTE or G-PON.
Subject Networks Applying IPv6 Note
Wireless
LTE O Commercial
WCDMA X
Wi-Fi X
Wired
G-PON O Field Trial
HFC X
xDLS X

18. Contents
Background
IPv6 Transition Schemes
FAQ

19. Summary of IPv6 Transition Schemes
Subject Transition Schemes
Backbone Dual Stack
Access Networks
(LTE EPC)
NAT64, 464XLAT

20. Transition Scheme for Backbone
Dual stack can support both IPv4 and IPv6 access
networks.
There is no issue.
We don’t even need to apply Only-IPv6 to the
backbone.
Dual Stack
(Backbone)
IPv4
Access Networks
(WCDMA, Wi-Fi)
IPv6
Access Network
(LTE)
Public
Network

21. Case#1: IPv6 is enabled on contents server
(End-to-End IPv6 connectivity)
Transition Scheme for Access Network
Case#2: IPv6 is not enabled on contents servers

22. PDN-GW
Dual Stack
Network
LTE Device
(Only IPv6)
Dual Stack
Only IPv6
Case#1: IPv6 is enabled on contents server
(End-to-End IPv6 connectivity)
Transition Scheme for Access Network (contd)

23. Transition Scheme for Access Network (contd)
Case#2: IPv6 is not enabled on contents servers
PDN-GW
Public
Network
NAT64
DNS64
LTE Device
(Only IPv6)
Only IPv4
Only IPv4
SKT should support
that only-IPv6 subscribers can connect to
only-IPv4 contents server.
NAT64, DNS64

24. Algorithm of NAT64, DNS64
PDN-GW
Public
Network
NAT64
DNS64
LTE Device
(IPv6-Only)
IPv4-Only
IPv4-Only
① Customer tries to connect to www.naver.com
② LTE device asks DNS64 server what is an IP address of www.naver.com
③ DNS64 server responds ‘64:ff9b::www.naver.com’
④ LTE device tries to connect to ‘64:ff9b::www.naver.com’
⑤ NAT64 translate IPv6 packet to IPv4 packet

25. Drawback of NAT64 Algorithm
Some applications are Hard Coded as only IPv4
address instead of domain name.
∙ IPv6 LTE device doesn’t ask DNS64 server.
∙ Only IPv6 LTE device can’t interpret an IPv4 address.
Error occurred !!

26. 464XLAT Overview
RFC 6877, “464XLAT: Combination of stateful and
stateless translation” (Information Track)
Provided by Android OS by default
T-Mobile USA and SKT adopted

27. 464XLAT Architecture
464XLAT has two operations, CLAT and PLAT
Subject CLAT PLAT
Full Name Customer-side translator Provider-side translator
Location In cellphone In operator’s network
Translation IPv4  IPv6 IPv6  IPv4

28. 464XLAT Operation
Subject Interface Source Address
Data
Packet
LTE Data
Original
Allocated from P-GW (e.g. 2001:290::1)
CLAT
“192.0.0.4” (dummy IPv4 address)
“LTE data interface ::464” (e.g. 2001:290::464)
Voice
Packet
LTE IMS Allocated from P-GW (e.g. 2001:2b8::1)
LTE device has 3 outgoing interfaces

29. 464XLAT Operation (contd)
If android OS find a hard coded for IPv4 address(1.2.3.4),
android OS will transfer packet via CLAT interface.
CLAT
PLAT
(5.6.7.8)
Content Server
(1.2.3.4)
Src: 192.0.0.4
Dest: 1.2.3.4
Src: 2001:290::464
Dest: 64:ff9b::1.2.3.4
Src: 2001:290::464
Dest: 64:ff9b::1.2.3.4
Src: 5.6.7.8
Dest: 1.2.3.4
Src: 5.6.7.8
Dest: 1.2.3.4

30. Verify 464XLAT Schemes
Verified 15 hundreds applications while
preparing the commercial service.
A few applications have trouble due to
customer’s circumstance.

31. Background
IPv6 Transition Schemes
Contents
FAQ

32. Which handset OSs and models are
supported an IPv6 service?
∙ We applied to only android OS not iOS.
∙ We applied to Galaxy Note 4 first. (‘14.9.24)
∙ We have applied to all new devices including
tablet since then.

33. Do you support IMS service(VoLTE)
also?
∙ Of course.
∙ We support an IPv6 service of LTE Data
and LTE Voice.

34. Do you support international
roaming service?
∙ Not yet.
∙ We don’t have a plan to launch now.
Do you support Wi-Fi service?

35. Do you support tethering service?
∙ Yes.
∙ LTE device allocates an IPv4 address not
IPv6 address to laptop.
LTE Device
(IPv6 Address)Laptop
(IPv4 Address)
Public
IPv6 Network

36. Do you satisfy the quality of IPv6
data and IMS service compared to
IPv4 ?
∙ Yes.
∙ We can’t find the quality difference
between IPv4 and IPv6 service.

37. Can I know about the increase of
IPv6 users and IP deployment since
commercial service ?
∙ I’m sorry but, I can’t inform that.
∙ IPv6 users and the CapEx for IP deployment
are restricted document.

38. Can I know about the increase of
IPv6 traffic since commercial service
?
∙ Recent IP equipment(ex> Router, P-GW) can’t
distinguish between IPv4 traffic and IPv6
traffic.

39. Do you inform your customers that
they are serviced by IPv6 ?
∙ No.
∙ Our aim is that our customer can’t
recognize which service is provided.

40. How to utilize the collected Public
IPv4 addresses ?
∙ Private IPv4 addresses were used to
VoLTE Service.
∙ We are currently allocating Public IPv4
addresses to VoLTE service to raise voice
quality.

41. Do you have a plan to launch the
new BM based on IPv6 ?
∙ Yes.
∙ We are developing the cellular based
IoT Service (ex> MTC, NB CIoT).