1
TSB
A Policy Look at IPv6
Richard Hill
April,2003
Telecommunication Standardization Bureau
International Telecommunication Union
Based on a paper by John Klensin,available at:
http://web/itudoc/itu-t/com2/infodocs/015.html
2
TSB
Outline
What is IPv6
Address space exhaustion
Relationship to topology
Alternatives to IPv6
Network problems
Space allocation policy
Deployment difficulties
Roadblocks and solutions
ITU and IPv6
About the ITU
3
TSB
What is IPv6
IPv6 (Internet Protocol,version 6) was
developed by the Internet Engineering Task
Force (IETF),starting in 1993,in response
to a series of perceived problems,primarily
with exhaustion of the current,IP version 4
(IPv4),address space
4
TSB
Address space exhaustion (1/3)
Rate and scale of Internet growth was
underestimated
In 1970’s,32-bit address space was thought
to be adequate for long term
Class system (A,B,C)
Internet routing is closely tied to the
separation of routing within a network and
routing between networks
5
TSB
Address space exhaustion (2/3)
Routing within large networks became
complex
Sub-netting introduced
Advent of PCs meant that each host could
no longer have a unique fixed IP address
– dynamic address assignment (but reachability?)
– private address spaces (but leakage if connected
to public network)
6
TSB
Address space exhaustion (3/3)
In 1995,classless system was introduced
RIRs became more conservative with
respect to address allocation
Some believe IPv4 addresses will be
exhausted in 2-3 years,others in 10 years,
others sooner,others much later.
Rate of exhaustion influenced by
technology (e.g,NATing) and RIR policies
as well as growth
Under-use of certain class A,B allocations
7
TSB
Relationship to topology (1/3)
An IP address is not similar to a telephone
number
An IP address is a routing address
In telephony terms:
– a telephone number is more like a domain name
– an IP address is more like a SANC
8
TSB
Relationship to topology (2/3)
But analogies are imperfect
– Telephone numbers identify a circuit,a wire
going somewhere,but are now portable
– IP addresses identify a terminal device,a
computer,but can be:
dynamically assigned
translated (NATing)
9
TSB
Relationship to topology (3/3)
Any host can access any other host through
uniform protocols and addresses
Network is dumb
Intelligence at the edges
Applications independent of network
Network does not change content
Back to the basics of Internet:
These differences are more important than the
packet vs,switched models
10
TSB
Alternatives to IPv6
Application servers at boundary of public
network,translate to private network,but
these gateways can limit functionality
NATing,VPNs,private spaces,but may
force re-numbering
– NATing limits peer-to-peer applications
– IPsec requires end-to-end
11
TSB
Network Problems
Expanding address space raises certain issues
Routing table growth (IPv6 may help or
hinder)
Blocks allocated to ISPs to optimize routing
limit portability across ISPs
Security may or may not be improved
12
TSB
Space allocation policies
RIRs allocate to LIRs (optimizes routing)
If IPv6 policies are conservative,this may
slow the adoption of IPv6
If IPv6 policies are loose,this may lead to
routing table problems and early exhaustion
13
TSB
Deployment difficulties
Dual stack,v4 and v6 in devices
Tunnels,encapsulate v4 in v6 or v6 in v4
Conversion gateways
Convert networks
– from the edges
– from the core
– by islands,either geographic or by application (3G)
14
TSB
Potential roadblocks and solutions
Cost of conversion
Lack of confidence in v6 software
Policies (will)
Consensus is that conversion is needed,but
when and how will depend on many factors
15
TSB
ITU and IPv6
ITU’s mission includes providing
information on new technologies to its
membership,IPv6 is a good example
A Tutorial Workshop was held in Geneva
on 6 May 2002,see http://www.itu.int/ITU-
T/worksem/ipv6/index.html
Further events are being considered
16
TSB
What is ITU?
International treaty organization founded in 1865 to
facilitate international interconnection of telegraphy
Unique partnership of industry and governments
Three sectors:
– Development (aid to developing countries)
– Radio (radio spectrum and satellite slot allocations)
– Standardization (formerly CCITT,for example modem
standards) (now called ITU-T; secretariat is called TSB)
In ITU-T industry and government work together to
develop mutually agreed non-binding Recommendations
17
TSB
Goals of ITU-T
“The functions of the Telecommunication
Standardization Sector shall be,bearing in mind
the particular concerns of the developing
countries,to fulfill the purposes of the Union
relating to telecommunication standardization,as
stated in Article 1 of this Constitution,by
studying technical,operating and tariff Questions
and adopting Recommendations on them with a
view to standardizing telecommunications on a
worldwide basis.”
18
TSB
IP project–areas of study
Integrated architecture
Impact to telecommunications access infrastructures of access to IP
applications
Interworking between IP based network and switched-circuit networks,
including wireless based networks
Multimedia applications over IP
Numbering and addressing
Transport for IP-structured signals
Signalling support,IN and routing for services on IP-based networks
Performance
Integrated management of telecom and IP-based networks
Security aspects
Network capabilities including requirements for resource management
Operations and Maintenance (OAM) for IP
19
TSB
An example of ITU-T work
ENUM is an IETF protocol for mapping telephone numbers into
the DNS,IETF asked ITU to facilitate government approval of
ENUM implementations,given that telephony is still regulated in
most countries
No real technical issues
Complex regulatory issues
After considerable discussion,most determined to be national
matters
Under agreed procedures
– RIPE NCC will ask TSB if country approves ENUM delegation request
– If yes,it proceeds
– If no or no answer from country,it does not proceed (TSB objects)
TSB does not itself evaluate requests in any way,RIPE NCC
checks technical aspects of requests
See http://www.itu.int/ITU-T/inr/enum/index.html
20
TSB
What ITU-T is not
The ITU-T does not do the following:
World-wide regulation
Consider issues that are national matters
Binding recommendations
Top-down decisions
Impose contractual terms or operating rules on private companies
Work in non-transparent ways
Act bureaucratically
Have staff that decides policies
Collect fees other than membership fees (with the exception of
minor cost-recovery activities)
21
TSB
What is ITU’s Situation (1/5)
ITU participation and coordination do not imply
ITU control or government control.
A good example is the international telephone
numbering scheme,which is coordinated by
ITU-T and is universally considered to work to
the satisfaction of the general public; however,
telephone services are not controlled by ITU-T
and are provided by private companies
22
TSB
What is ITU’s Situation (2/5)
ITU-T is a dynamic,well-respected industry-
government partnership (650 Sector Members)
Examples of ITU-T Recommendations:
– G.723.1 & G.729 - Speech coding for Voice over IP and other
applications
– H.323 - Packet based multimedia communication systems -
the protocols behind Voice over IP,along with,
H.245 - Control protocol for multimedia communications
H.248 - Gateway control protocol (developed jointly with IETF)
– X.509 - Public-key encryption
– V.90 - 56kbit/s PSTN modems - providing ubiquitous
worldwide internet access
– G.99x series - xDSL Recommendations for broadband access
23
TSB
What is ITU’s Situation (3/5)
ITU-T Approval and publication times
before 1988 1989-1993 1993-1996 1997-2000 2001-2004
Approval
time
4 years
2 years
18 months
9 months
(exceptional
case,
5 months)
2-9
months
Publication
time
2-4 years
2 years
1-1.5 year
6-12
months
3-9 months
Notes,1,Pre-published Recommendations,available on ITU-T Website,from a few days
to four weeks after approval of the text,
2,Recs in force,pre-published,superseded/obsolete,available on ITU-T Website,
3,Forms of publication,paper,CD-ROM,electronic bookshop,online,etc,
4,FREE ONLINE ACCESS SINCE JANUARY 2001 (one free access per member,
3 free downloads for public)
5.,Approval time” counted between,determination/consent” and final approval
24
TSB
What is ITU’s Situation (4/5)
ITU-T working methods are fast and efficient,
for example,190 Recommendations have been
approved under Alternative Approval Process in
2001,more than 60% in less than 2 months (ex,
E.129,Representation of national numbering
plans)
ITU membership has increased in the private
sector
Non-government (non-profit) organizations can
apply for ITU membership
25
TSB
What is ITU’s Situation (5/5)
ITU-T–Electronic Publishing
All Recommendations available online
Key databases (for example,telephone
country codes) available online
Working documents available online
See http://www.itu.int/ITU-T/
26
TSB
How does ITU-T Develop Recommendations?
Consensus of Sector Members and Member
States
Work typically driven by Sector Members
Open (for members),transparent,bottoms-up
process
Sensitive to national sovereignty,will only cover
matters not considered to be national
Will not impose contractual terms or operating
rules on private companies
Recommendations are not binding,but tend to be followed because
they represent a true consensus,