The State of 3G/GPRS IPv6 Deployment

John Loughneyjohn.loughney@nokia.com

North American IPv6 Technology ConferenceSeptember 20th, 2005

Agenda• IPv6 status in 3G standards• Why IPv6• Why not IPv6• Conclusion

IPv6 in 3GPP Specifications• Support for IPv6 (for user traffic) was fully introduced in

3GPP Release 99. This is what is currently deployed.• IPv6 address allocation mechanism was updated in 2002

to allocate a globally unique (/64) prefix (instead of a single address) for every primary PDP context.

• IP Multimedia Subsystem (IMS) - multimedia service infrastructure introduced in Release 5 specifies IPv6 as the only IP version in the IMS to avoid IPv4-IPv6 transition and interworking problems.

• Some work is on-going for support for early IMS implementations (a.k.a. – IPv4 IMS deployments).

Transition to IPv6 in 3GPP networks• Analyzed in the v6ops Working Group (IETF)

• Transition Scenarios for 3GPP Networks - RFC 3574 • 3GPP Analysis - draft-ietf-v6ops-3gpp-analysis-11.txt (in RFC

Editor’s Queue)

• GPRS transition scenarios:1. Dual Stack terminal connecting to IPv4 and IPv6 nodes 2. IPv6 terminal connecting to an IPv6 node through an IPv4 network3. IPv4 terminal connecting to an IPv4 node through an IPv6 network4. IPv6 terminal connecting to an IPv4 node5. IPv4 terminal connecting to an IPv6 node

• IMS transition scenarios:1. Terminal connecting to a node in an IPv4 network through IMS 2. Two IPv6 IMS operators connected via an IPv4 network

WLAN-3GPP Service Scenarios• 3GPP defined service scenarios [TS 22.934]• Scenario 1 - Common Billing and Customer Care

• Single customer relationship ⇒ Customer receives one bill from the usage of both cellular & WLAN services

• Scenario 2 - 3GPP system based Access Control and Charging• Authentication, authorization and accounting (AAA) are provided by the 3GPP system,

for WLAN access

• Scenario 3 - Access to 3GPP system PS based services • The same services provided by GPRS can be accessed by WLAN

• Scenario 4 - Service Continuity• Services supported in scenario 3 survive an inter-system handover between WLAN and

3GPP. The change of access may be noticeable to the user.

• Scenario 5 - Seamless Services• Seamless service continuity between the access technologies.

• Scenario 6 - Access to 3GPP CS Services• CS core network services supported over WLAN

IPv6 in• 3GPP2 IS-835C specifies Simple IPv6

– /64 addresses through PPP.– no duplicate address detection.

• 3GPP2 IS-835D specifies Mobile IPv6– Open issues on MIPv6 and firewall traversal

• 3GPP2 and 3GPP are co-operating on IMS– 3GPP2 IMS supports both IPv4 and IPv6

Transition Scenarios for 3GPP2

• Slightly more complicated - many scenarios for network transition.

• Simple IPv4 -> Simple IPv6• Mobile IPv4 -> Simple IPv6• Mobile IPv4 -> Mobile IPv6

• Various choices for upgrading to IPv6• Upgrade mobile terminals and PDSNs (Packed Domain Service

Node) and services to dual-stack, operator core network I s IPv4.• Upgrade only mobile terminals and some services to dual-stack.

Employ transition mechanism on mobile.

• Use of IPv6 transition mechanisms with MIPv6 is an open issue.

The Good News• The Wireless Intelligence, jointly established by GSM

Association and Ovum, released a survey report recently, showing that global mobile phone subscribers have exceeded 2 billion.

• There are about 200 million 3G users (CDMA + WCDMA).• IPv6 implementations are done (details coming).• Mobile operators have IPv6 allocations.

• For example: Vodaphone, ePlus, Telefonica, France Telecom, NTT DoCoMo, Sprint … all have IPv6 allocations.

Why IPv6?• Applications benefit from peer-to-peer addressing

• Push-to-Talk, SIP messaging, multimedia, VoIP & group communication.• Peer-to-peer games• IPsec VPNs

• NAT traversal is complex & expensive • How to manage global roaming with private addresses?• UDP traffic requires keep-alives (every 45 seconds) – huge power drain!• SIP, IPsec, MIP all have different solutions.

IPv6

+44 3 1234567 +44 9 7654321

1080::1:1:2:ABBA:CAFE 1080::AAAA:1:2:3:4

END-TO-END PHONE CALL

END-TO-END IP MULTIMEDIA CONNECTION

IPv6 Products…Gaining Momentum• Symbian supports IPv6

• All Nokia 3G Symbian phones support IPv6 – 9 models already.

• Nokia phones with embedded IPv6 – over 10 models• Microsoft Windows XP, Windows Mobile 2003 2nd Ed.,

Windows server 2003 all support IPv6.• Linux, HP-UX, AIX, & Solaris all are shipping IPv6.• Most infrastructure vendors support IPv6

• Nokia shipping IPv6 in networks.• Cisco announced IPv6 support from IOS 12.2(1)T.

Real Time Apps & NATs

• Even though sessions may use a server, NATed addresses still cause problems.• UDP inactivity timers are used with NATs and cause some problems:

• The mobile would need to send keep-alive packets to every used public UDP socket every 30 seconds. This generates unnecessary traffic and is very bad for battery life.

• This is applicable for SIP, IPsec, MIP and many other protocols• Mobiles can easily use up all of the operators public IPv4-addresses due to the

keep-alives so that the public UDP ports can’t be assigned to new mobiles.

Client, Private IPv4 address 1

Server, Public IPv4 address 3

Client, PrivateIPv4 address 2

UDP port = 6538

The UDP inactivity timer in NATs causes the public UDP port 6538 to be assigned to a different mobile, if the mobile does not send any data within a certain amount of time, about every 40 seconds …

There should be NO NATs between the

terminal and the server!

More NAT problems• Current mobile networks tend to have large numbers of

short-lived connections.• Quick web browsing• Picture sending• Email

• Large, global operators have seen private IP addresses are being re-assigned before NAT bindings time out.

• This is a huge security hole, as the data session may still be active and if the NAT binding is still active, someone might be gettingyour data.

• To solve this, operators have shortened they NAT binding life-time, meaning NAT refreshes are need more often.

IMS with IPv6Multi-country/operator

SIP-connectivity network

Client, Public IPv6 address 1Client, Public IPv6 address 2

PublicIP-routing domain

(inter-operatorconnections)

SIP Proxy

SIP Proxy

SIP Signaling:A’s address = Public IPv6 Addr 1

Media from B to A:Sent to Public IPv6 Addr 1

• Current GPRS networks use private addresses almost exclusively.

• Lots of users require port reservations which can use much of the operator’s public IPv4 address space.

• Peer-to-peer connections can be expanded to inter-operator and inter-country whenever the operator wants to do so …

Dual Stack Handsets • One common misconception is that IPv6 stack,

especially dual stack, is heavy on terminals.• IPv6 TCP/IP stack size is comparable to IPv4

TCP/IP stack.• Dual stack (IPv4 and IPv6) size is NOT multiple

times the size of IPV4 stack.• Dual stack (v4/v6) is comparable (only about 15% bigger

than) IPv4 TCP/IP stack.

• Direct correspondence between IPv4 socket library and IPv6 socket library – porting does not require major changes in applications.

Advantages of Dual-Stack

• Does not require tunneling on the wireless link.• Tunneling adds overhead.• Pricing issues on wireless usage.• Bandwidth and latency issues on the wireless link

• Services can be upgraded to IPv6 in a phased manner.

• Use of DNS records (AAAA or A records) is the central control point for transitioning services.

• For the most part, only software upgrades are required for network entities.

Why not IPv6• There are a lot of concerns still with IPv6 in mobile

networks. • Configuration & management might be hard – knowing

when to use IPv6 and when not to.• How to manage roaming, when local networks don’t

support IPv6.• Operators think NATs help provide a walled-garden.• Initial ‘just use IPv6’ for IMS was too simplistic – there are

still some real issues on how to configure and manage dual-stack scenarios.

• WLAN interworking causes problems as WLAN networks are considered to be IPv4 only.

Summary• IPv6 resolves IPv4 address space limitations and enables peer-to-peer

connectivity on a global scale.

• There will be co-existence of IPv4 and IPv6, both on hosts & servers.1.Enable IPv6 in end-nodes and key parts of the network infrastructure.2.Make applications use IPv6, which may be more configuration than anything

else. 3.Plan for configuring mobile nodes and get IPv6 inter-connections working.

• Enabling IPv6 in mobile network is relatively straight-forward.• Commercial IMS network elements & IMS services (file sharing, peer-to-peer

gaming, ...) already deployed in a number of countries.• IPv6 is an important enabler for IMS & SIP - however, IPv6 can be used for

more – secure communications, mobility and multiradio uses.

• In the end, it’s all about “Connecting People”