1 © 2001, cisco systems, inc. all rights reserved. ipv6: addressing the future fred baker cisco...
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1© 2001, Cisco Systems, Inc. All rights reserved.© 2001, Cisco Systems, Inc. All rights reserved.© 2001, Cisco Systems, Inc. All rights reserved.
IPv6:Addressing the Future
Fred Baker
Cisco Fellow
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Points to ponder
• The past: where networks came from
• The future: where networks are going
• IPv6 innovations: what is really different?
• IPv6 debate: is IPv6 really a sufficient solution?
• IPv6 today: status in implementation and deployment
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The Past
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Before IP
• Diverse networks joined by application-layer gateways
Inevitable loss of functionality crossing proprietary application and network boundaries
Difficult to deploy multi-network applications
Hard to diagnose and remedy problems
Stateful gateways inhibited dynamic routing around failures
• No global addressability
Ad-hoc, application-specific solutions
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Fundamental Premises:
• Simple Applications, Smart Network
Able to provide high quality services to specific applications
Network does one thing well: deliver specified services to specified applications
Intolerant of change
• Simple Network, Smart Applications
End to End Principle
Network does one thing well: ship packets
Applications can do anything that can use that paradigm
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The IP Solution
• IP routers & global addresses
Simple, application-independent, least-common-denominator network service: best-effort datagrams
Stateless gateways could easily route around failures
• With application-specific knowledge out of the gateways:
Anyone could deploy new, internet-wide applications and services
Internet became a platform for rapid, competitive innovation
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The Internet Today
• Network address translators and application-layer gateways
Inevitable loss of some functions
Difficult to deploy new internet-wide applications
Hard to diagnose and remedy problems
Stateful gateways inhibit dynamic routing around failures
• No global addressability
Ad-hoc, application-specific (or ignorant!) Solutions
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The Future
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The Probable Future
• Billions and billions of new Internet devices
• Billions of new Internet users
• Internet available everywhere, all the time (wired, wireless, mobile,…)
• Convergence of all communication on the Internet (business, personal, entertainment, public services,…)
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The Unknown Future
• Continued degradation of the end to end model with IPv4?
• More complex and volatile network service
=> Lower performance, less robust, less secure, less manageable
• More centralized control over new applications and services
=> Significant barrier to innovation and growth
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The Unknown Future
• …or restoration of the end to end model with IPv6?
• Simple, stable network service
=> Higher performance, more robust, more secure, more manageable
• Enabling anyone to provide new applications and services
=> Allowing rapid innovation and growth
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IPv6 Innovations
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Lots of Addresses
• IPv4 Internet: O(232) = 4,294,967,296 addresses
Arbitrary division into networks
12.5% allocated to non-host addresses
~45% allocated to various networks
~26% advertised in today’s Internet
Conservatively allocated
• IPv6 Internet: O(2128) = 3.4*1038 addresses
O(264) = 18,446,744,073,709,551,616 Networks
O(264) = 18,446,744,073,709,551,616 hosts per network
Host addresses self-allocated
Enough!
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Plug-and-play
• One of the nice things about AppleTalk:
You can plug the device or computer in, and it just works
• One of the not-so-nice things about IPv4:
You can plug the device or computer in…
Configuring, and reconfiguring, can be hard
DHCP helps a lot, but it requires properly configured servers
• IPv6 allows for
Significant level of autoconfiguration
Automated network renumbering
Arbitrary device addressing within topological limits
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Mobility
• IPv4 Mobility
Permits device to move using same home address
All communication through Home Agent
Foreign Agent must be a router
• IPv6 Mobility
Permits device to move using same home address
Communication via care-of address
No Foreign Agent required
Security Issues:
Session hijack
Duration of Switchover
Dogleg Routing
Optimized Routing
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Anycast
• Addressing and Naming of Applications
One of the nice things about NetWare: Service Location
Today: DNS lists several addresses for a name, but no information to help select a server
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Anycast
• Proposal:
DNS lists one address,
Servers are “routers” to that address
•DNS for service name,
•Common address for service location
•Topological address for specific access
• Issues:
Route changes can change which server you use in mid-transaction
• Solution:
Treat server as a mobile device which is currently stationary
Connect to “home address” to select server,
Thereafter talk to fixed “care-of address”
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Security issues
• IPv6 enables end-to-end use of IPsec protocols (because it eliminates NATs),
Plus for security, although IPsec also exists in IPv4 Internet and is widely used for VPNs
Authentication (“you are the person who knows this key”)
Antidote to session hijack (“you are the same person I was just talking with”)
Privacy (encryption, using symmetric or public key technology)
• IPsec authentication dependant on key distribution infrastructure, which is not currently a solved problem
Affects mobility, anycast, secure communication in general
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IPv6 Debate
Geoff Huston’s questions
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Are we really running out of addresses?
• Growth in IPv4 advertisement rate not high
But folks who need addresses can’t get them
• Largely a question of perspective
If you already have your addresses assigned, getting them is not a worry
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Everyone doesn’t want a permanent address
• Everyone who wants one is not able to get one
• Example: People’s Republic of China
1.3 Billion people
Order of magnitude growth in Internet usage year over year
~9M addresses in 1999
~16M addresses in 2001
• Do we simply assume that anyone who has not already asked never will?
Africa, South America, India, Arab world…
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Every device is not a server
• In client/server applications
Clients vastly outnumber servers
Clients can be addressed on demand
Examples: WWW, FTP, X-Windows
• But every application is not client/server
• Peer/peer applications
Peer must be accessible and addressed when someone decides to talk with it
• Do we want to limit ourselves to the client/server model?
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Privacy?
• Privacy issues
Concern: inclusion of MAC address in IPv6 breaks privacy
Reality: 1:1 correlation between IP and MAC Address breaks privacy in either IPv4 or IPv6
• Privacy solutions in IPv6
Autoconfiguration procedures enable, for example
Random address changes every hour
Address per user of multi-user machine
Address per TCP session or per web page loaded
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Number of usable addresses
• Argument:
IPv4+port gives 248 effective addresses
IPv6 allocation gives 248 networks, 216 subnets, and a few hosts in each subnetwork
Comparable when viewed on the service provider network
• Not really comparable
Math error: 248 248+16
Not responsive to user network design issues
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Is it enough better to justify changing?
• Argument:
IPv6 doesn’t change routing, trust model, QoS, etc
It gives us IPv4 Internet with more addresses
• What IPv6 does do:
Removes address conservation as an issue
Enables kinds of applications current addressing makes difficult
Simplifies deployment of new applications
Eliminates need to kludge around addressing issues
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IPv6 Today
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Standards
• Core IPv6 specifications are IETF Draft Standards=> well-tested & stable
IPv6 base spec, ICMPv6, Neighbor Discovery, PMTU Discovery, IPv6-over-Ethernet, IPv6-over-PPP,...
• Other important specs are further behind on the standards track, but in good shape
Mobile IPv6, header compression, A6 DNS support,...
For up-to-date status: http://playground.sun.com/ipng
• UMTS R5 cellular wireless standards mandate IPv6
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Implementations
• Most IP stack vendors have an implementation at some stage of completeness
Some are shipping supported product today,e.g., Cisco, 3Com, *BSD(KAME), Epilogue, Ericsson/Telebit, IBM, Linux community, Hitachi, Nortel, Sun, Trumpet
Others have beta releases now, supported products soon,e.g., Compaq, HP, Microsoft
Others rumored to be implementing, but status unknowne.g., Apple, Bull, Juniper, Mentat, Novell, SGI
(see http://playground.sun.com/ipng for most recent status reports)
• Good attendance at frequent testing events
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Deployment
• Experimental infrastructure: the 6bone
for testing and debugging IPv6 protocols and operations(see www.6bone.net)
• Production infrastructure in support of education and research: the 6ren
CAIRN, Canarie, CERNET, Chunahwa Telecom, Dante, ESnet, Internet 2, IPFNET, NTT, Renater, Singren, Sprint, SURFnet,vBNS, WIDE(see www.6ren.net, www.6tap.net)
• Commercial infrastructure
Some ISPs (IIJ, NTT, SURFnet, Trumpet,…) have announced commercial IPv6 service or service trials
Japan and China have announced national direction
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Deployment (cont.)
• IPv6 address allocation
6bone procedure for test address space
Regional IP address registries (APNIC, ARIN, RIPE-NCC)for production address space
• Deployment advocacy (a.k.a. marketing)
IPv6 Forum: www.ipv6forum.com
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Conclusions
• IPv6 is addressing the future…
Addresses for new devices, new applications, and new users
Restoring the end to end model, for performance, robustness, security, manageability, and enabling rapid innovation
Enhancing IP for next-generation applications: multicast, mobility, plug-and-play, security, and multiple qualities of service
• …but is it a future we will see?
Must apply much more energy, in design, implementation, deployment, transition, training, explaining,…
The only way to fight entropy is to apply energy