Internet Goes Mobile
Alper Yegin
KIOW 2003 at APNIC 16 August 19th, 2003. Seoul, Korea
Internet - Yesterday
T1 Enterprise Network
Internet
Dial up DSL
Home user Home Network
1
Internet - Today and Tomorrow
W-CDMA T1 Enterprise Network
Community Network
Operator Network
Internet
Dial up DSL PAN Home user Home Network Home Network Mobile Network DSL GPRS
2
Challenge
• Users expect the same characteristics (greedy!)
– – – – Secure Reliable Seamless High performance
• Burden is on:
– Standards bodies (IETF, IEEE, 3GPP, 3GPP2, etc.) – Vendors – Operators
3
Security
• First things first! • Physical security is replaced with cryptobased security
– Threats: Eavesdropping, spoofing – Not a full replacement!
• Crypto designs and experts get a good exercise!
4
Solutions
• Good solutions:
– 3GPP, 3GPP2
• Bad solutions
– IEEE WEP fiasco!
• Practical but less than adequate solutions:
– WECA WISPer: HTTP redirect and web-based login hackery
• Practical and reasonable solutions:
– IEEE 802.11b access outside VPN gateway
5
The Right Solution
• Authenticate, authorize the client • Accounting and privacy
Home AAA
Diameter, RADIUS
ISP AAA
Home Network Diameter, RADIUS Visited Network
Access Router
AP host PANA, 802.1X 6
The Right Solution
• IETF AAA, EAP, and PANA Working Groups • IEEE 802.11i, 802.1aa
Home AAA
Diameter, RADIUS
ISP AAA
Home Network Diameter, RADIUS Visited Network
Access Router
AP host PANA, 802.1X 7
Global AAA
• AAA web of trust is here (unlike global PKI) and more capable.
AAA server AAA broker AAA broker AAA server AAA server
Home Network
AAA server
Visited Network
Home Network
Visited Network
8
Impact
• Security is never plug-and-play (plug-and-gethacked!) • Additional infrastructure
– Front-end AAA servers (NAS) – Backend AAA servers (RADIUS, Diameter servers) – VPN gateways
• Configuration
– On the clients – Per-client configuration on the servers (keys, authorization parameters, etc.) – Configuration to join the AAA web-of trust
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Impact
• Increased popularity of IPsec and TLS
– AAA requires confidential information exchange – VPN – Anonymizer.com
• Strengthening internal network is a MUST
– Unless you are 100% sure that wireless access is secure – Partitioning, IDS, enforcing strict policy execution (social aspects)
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But Still
• …. You are vulnerable to attacks!
• Price of going wireless
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Mobility Management
• Host at home (fixed Internet).
Access Router
Web server
AP a::/64
Home Network Visited Network
host a::1
Access Router
Access Router
Access Router
AP
AP AP
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Mobility Management
• You move, you break!
Access Router
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
b::/64 host b::1 AP AP
13
Mobile IP
• IETF Mobile IP Working Group
– www.ietf.org/html.charters/mobileip-charter.html
Home Agent Access Router
home address
care-of address
Web server
a::1b::1
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
b::/64 host b::1 AP AP
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Mobile IP
• Traffic tunneled through home network
Home Agent Access Router
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
b::/64 host b::1 AP AP
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Mobile IP
• End-to-end signaling for route optimization
Home Agent Access Router home address care-of address
Web server
AP
Home Network Visited Network
Access Router Access Router
a::1b::1
Access Router
AP
b::/64 host b::1 AP AP
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Mobile IP
• Most direct path for data traffic.
Home Agent Access Router
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
b::/64 host b::1 AP AP
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… Fast and Smooth
• Problem: Signaling latency.
Home Agent Access Router new care-of address
Web server
AP
Home Network Visited Network
Access Router Access Router
a::1c::1
Access Router
AP
AP AP c::/64 host c::1 18
… Fast and Smooth
• Fast Handovers
– draft-ietf-mobileip-fast-mipv6-06.txt
• IETF Seamoby Working Group
– www.ietf.org/html.charters/seamoby-charter.html
Home Agent Access Router
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
AP
old care-of address
b::1c::1
AP c::/64 host c::1 19
new care-of address
… Fast and Smooth
• Context transferred and routes fixed.
Home Agent Access Router
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
AP AP c::/64 host c::1 20
… Privacy
• Hide precise location and movement.
Home Agent Access Router
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
AP b::/64 cafeteria AP c::/64 CEO’s office
d::/64 host d::1
employee office
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… Privacy
• Obtain an IP address from the localized mobility agent.
Home Agent Access Router regional care-of address home address local care-of address Localized Mobility Agent
Web server
AP
Home Network
e::/64 e::1d::1 Visited Network
Access Router Access Router Access Router
a::1e::1
AP
AP b::/64 AP c::/64
d::/64 host d::1 22
… Privacy
• Correspondent sends packets directly to the agent. Agent tunnels them to the precise location.
Home Agent Access Router Localized Mobility Agent
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
AP b::/64 AP c::/64
d::/64 host d::1 23
… Privacy
• Correspondent does not know the real IP destination, or when it changes.
Home Agent Access Router Localized Mobility Agent
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
AP host b::1 b::/64 AP c::/64 24
… AAA
• Mobility management is a for-profit “service”
Home Agent Access Router Home AAA Localized Mobility Agent ISP AAA
Web server
AP
Home Network Visited Network
Access Router Access Router
Access Router
AP
AP host b::1 b::/64 AP c::/64 25
… Network is Mobile
• IETF NEMO Working Group
– www.ietf.org/html.charters/nemo-charter.html
Visited Network
Access Router Access Router Access Router
Base Station
Base Station
Base Station
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Impact on Intranet
• More stateful servers
– Home agents, access routers (for context transfer and fast handovers), localized mobility agents – Mobile IP bindings, tunnels, host-routes – Redundancy and fault-tolerance are MUST!
• More configuration
– Per client on the servers – Trust relations among communicating servers
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Impact on Internet/Intranet
• Tunnels
– Several levels of nesting
Web server
Home Agent
Localized Mobility Agent Previous Access Router Current Access Router
host
Home Address
(Regional) Care-of Address
(Older local) Care-of Address
(Current local) Care-of Address
Fast Handovers Localized Mobility Management Mobile IP 28
Impact on Internet
• Address consumption
– Always-on hosts – Purpose-specific address usage (home address, care-of address) – Multihomed devices (GPRS, IEEE 802.11b, Bluetooth) – Sensor networks
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Impact on Internet
• Suboptimal routing, redirect servers
host A
Home Agent A
host B
Home Agent B
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Host Assumptions
• Can be anything:
• Dynamic auto-configuration needed:
– IPv6 address auto-configuration (RFC 2462) – IPv6 prefix delegation (draft-troan-dhcpv6-opt-prefixdelegation-02.txt) – Service discovery (IPv6 anycast address support) 31
IPv6
• IPv6 benefits:
– Ability to run server apps on devices (accept incoming connections) – Plug-and-play – End-to-end IPsec for thwarting first-hop and last-hop threats – Mobile IPv6 : Efficient, easy to deploy and manage, and scalable mobility protocol – Extensibility
• Mobile and wireless Internet will expedite the transition from IPv4-NAT to IPv6 • www.isoc.org/briefings/014/index.html
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Conclusion
• Wireless and mobility provide tremendous benefits, but they come with a price. • Transitioning the Internet protocols, architectures, products, and running networks should be done very carefully.
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Questions?