What’s Happening with
IPv6?
October, 2001
Steve Deering
deering@cisco.com
1
IP Scaling Problems —
the View from Late 1991
• running out of Class B addresses (near-term)
solution: CIDR (Classless Interdomain Routing) to allow addresses
to be allocated and routed as blocks of any
power-of-two size, not just Class A, B, and C
• running out of routing table space (near-term)
solution: provider-based delegation of address blocks, i.e.,
address hierarchy changed from organization:subnet:host
to provider:subscriber:subnet:host
• running out of all IP addresses (long-term)
solution: a new version of IP with bigger addresses,
dubbed IP Next Generation, of IPng
note: this was before the Web!
2
IPng Candidates
“IPv7”
(Ullman)
TP/IX
CATNIP
TUBA
(Callon)
ENCAPS
(Hinden)
IPAE
SIP
(Deering)
IPv6
SIPP
Pip
(Francis)
Jan 92
Jul 92
Jan 93
Jul 93
Jan 94
Jul 94
3
What’s Been Happening Since Mid
1994?
• writing protocol specs, arguing about every detail,
and progressing through the IETF Standards process
– scores of documents, on IPv6 address formats and routing
protocols (unicast & multicast), L2 encapsulations, autoconfiguration, DNS changes, header compression, security
extensions, IPv4/IPv6 co-existence & transition, MIBS,…
(see playground.sun.com/ipv6 for list of documents)
• implementation by vendors, and interoperability
testing
• building deployment testbeds
• shipping products
• deploying production services
4
Why IPv6?
(Theoretical Reasons)
only compelling reason: more IP addresses!
• for billions of new users (Japan, China, India,…)
• for billions of new devices (mobile phones, cars, appliances,…)
• for always-on access (cable, xDSL, ethernet-to-the-home,…)
• for applications that are difficult, expensive, or impossible to
operate through NATs (IP telephony, peer-to-peer gaming, home
servers,…)
• to phase out NATs to improve the robustness, security,
performance, and manageability of the Internet
5
IP Address Allocation History
1981
1985
1990
1995
2000
- IPv4 protocol published
~ 1/16 of total space
~ 1/8 of total space
~ 1/4 of total space
~ 1/2 of total space
• this despite increasingly intense conservation efforts
–
–
–
–
PPP / DHCP address sharing
CIDR (classless inter-domain routing)
NAT (network address translation)
plus some address reclamation
• theoretical limit of 32-bit space: ~4 billion devices
practical limit of 32-bit space: ~250 million devices
(see draft-durand-huitema-h-density-ratio)
6
Other Benefits of IPv6
• server-less plug-and-play possible
• end-to-end, IP-layer authentication & encryption possible
• elimination of “triangle routing” for mobile IP
• other minor improvements
NON-benefits:
• quality of service (same QoS capabilities as IPv4)
– flow label field in IPv6 header may enable more efficient flow
classification by routers, but does not add any new capability
• routing (same routing protocols as IPv4)
– except larger address allows more levels of hierarchy
• except customer multihoming is defeating hierarchy
7
Why IPv6?
(Current Business Reasons)
• demand from particular regions
– Asia, EU
– technical, geo-political, and business reasons
– demand is now
• demand for particular services
– cellular wireless (especially 3GPP[2] standards)
– Internet gaming (e.g., Sony Playstation 2)
– use is >= 1.5 years away (but testbeds needed now)
• potential move to IPv6 by Microsoft?
– IPv6 included in Windows XP, but not enabled by default
– to be enabled by default in next major release of Windows
– use is >= 1.5 years away
8
IPv6 Header compared to IPv4 Header
Ver. Traffic
Class
Payload Length
Flow Label
Next
Header
Hop
Limit
Hdr Type of
Ver. Len
Service
Identification
Time to Protocol
Live
Total Length
Flg
Fragment
Offset
Header
Checksum
Source Address
Source Address
Destination Address
Options...
Destination Address
shaded fields have no equivalent in the
other version
IPv6 header is twice as long (40 bytes) as
IPv4 header without options (20 bytes)
9
How Was IPv6 Address Size Chosen?
• some wanted fixed-length, 64-bit addresses
– easily good for 1012 sites, 1015 nodes, at .0001 allocation
efficiency (3 orders of magnitude more than IPv6 requirement)
– minimizes growth of per-packet header overhead
– efficient for software processing
• some wanted variable-length, up to 160 bits
– compatible with OSI NSAP addressing plans
– big enough for auto-configuration using IEEE 802 addresses
– could start with addresses shorter than 64 bits & grow later
• settled on fixed-length, 128-bit addresses
(340,282,366,920,938,463,463,374,607,431,768,211,456 in all!)
10
IPv4-IPv6 Transition / Co-Existence
Techniques
a wide range of techniques have been identified and
implemented, basically falling into three categories:
(1)dual-stack techniques, to allow IPv4 and IPv6 to
co-exist in the same devices and networks
(2)tunneling techniques, to avoid order
dependencies when upgrading hosts, routers, or
regions
(3)translation techniques, to allow IPv6-only devices
to communicate with IPv4-only devices
expect all of these to be used, in combination
11
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,...
– for up-to-date status: playground.sun.com/ipv6
• 3GPP UMTS Release 5 cellular wireless standards
mandate IPv6; also being considered by 3GPP2
12
Implementations
• most IP stack vendors have an implementation at some stage of
completeness
– some are shipping supported product today,
e.g., 3Com, *BSD(KAME), Cisco, Compaq, Epilogue, Ericsson/Telebit, IBM,
Hitachi, Nortel, Sun, Trumpet, …
– others have beta releases now, supported products “soon”,
e.g., HP, Juniper, Linux community, Microsoft, …
– others rumored to be implementing, but status unkown (to me),
e.g., Apple, Bull, Mentat, Novell, SGI, …
(see playground.sun.com/ipv6 for most recent status reports)
• good attendance at frequent testing events
13
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
– a few ISPs (IIJ, NTT, Telia…) have started or announced
commercial IPv6 service
14
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
15
Much Still To Do
though IPv6 today has all the functional capability of
IPv4,
• implementations are not as advanced
(e.g., with respect to performance, multicast support, compactness,
instrumentation, etc.)
• deployment has only just begun
• much work to be done moving application, middleware, and
management software to IPv6
• much training work to be done
(application developers, network administrators, sales staff,…)
• many of the advanced features of IPv6 still need specification,
implementation, and deployment work
16
IPv6 Timeline
(A pragmatic projection)
2000
2001
2002
2003
2004
2005
2006
2007
Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
Early adopter
Appl. Porting <= Duration 3+ yrs.=>
ISP adoption <= Dur. 3+ yrs.=>
Consumer adoption <= Dur. 5+ yrs.
=>
Enterprise adopt.<= 3+ yrs. =>
17
IPv6 Timeline
(A pragmatic projection)
2000
2001
2002
2003
2004
2005
2006
2007
Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
Early adopter
Appl. Porting <= Duration 3+ yrs.=>
ISP adoption <= Dur. 3+ yrs.=>
Consumer adoption <= Dur. 5+ yrs.
=>
Enterprise adopt.<= 3+ yrs. =>
Asia
18
IPv6 Timeline
(A pragmatic projection)
2000
2001
2002
2003
2004
2005
2006
2007
Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
Early adopter
Appl. Porting <= Duration 3+ yrs.=>
ISP adoption <= Dur. 3+ yrs.=>
Consumer adoption <= Dur. 5+ yrs.
=>
Enterprise adopt.<= 3+ yrs. =>
Asia Europe
19
IPv6 Timeline
(A pragmatic projection)
2000
2001
2002
2003
2004
2005
2006
2007
Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q
1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
Early adopter
Appl. Porting <= Duration 3+ yrs.=>
ISP adoption <= Dur. 3+ yrs.=>
Consumer adoption <= Dur. 5+ yrs.
=>
Enterprise adopt.<= 3+ yrs.
=>
Asia Europe Americas
20
Recent IPv6 “Hot Topics” in the IETF
•
multihoming
•
enhanced router-to-host info
•
address selection
•
site renumbering procedures
•
address allocation
•
inter-domain multicast routing
•
DNS discovery
•
•
3GPP usage of IPv6
•
anycast addressing
address propagation and AAA
issues of different access
scenarios
•
scoped address architecture
•
end-to-end security vs. firewalls
•
flow-label semantics
•
•
API issues
(flow label, traffic class, PMTU
discovery, scoping,…)
and, of course, transition /
co-existence / interoperability
with IPv4
(a bewildering array of transition
tools and techniques)
Note: this indicates vitality, not incompleteness, of IPv6!
21
Conclusions?
• if I knew it was going to take so long, I would have let
one of the other IPng candidates “win”!
• one shouldn’t expect it to have taken less time, given
the nature of the undertaking
• the IETF was unusually far-sighted (lucky?) in starting
this work when it did, instead of waiting till the Internet
falls apart
• the Internet is now falling apart
• IPv6 is ready to put it back together again
22