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Irish IPv6 Task Force

Introduction to IPv6

Fundamentals


Irish IPv6 Task ForceIrish IPv6 Task ForceIPv6 Training Slide-setsIPv6 Training Slide-sets

1. The Bigger Picture: Why is IPv6 so Important?

2. Introduction to IPv6 Fundamentals (technical) <- This slide set is second in a series

3. IPv6 Deployment & Strategy (technical)

4. The Business Case for IPv6

5. Mobile IPv6 (technical)

6. IPv6 Quality of Service (technical)

7. IPv6 Security (technical)


Presentation Presentation StructureStructure

• Introduction

• Why IPv6 was designed.

• IPv6 Addressing (format, types and policy).

• How IPv6 interacts with other layers

• Transition mechanisms.

• The current state of IPv6.


IntroductionIntroduction


IntroductioIntroduction n

• Introduction to IPv6 technical details.

• Only overview, not comprehensive.

• Further information in complementary

sources.

• Will also touch on policy/history where it

influences technical matters.


Why IPv6 was designed.Why IPv6 was designed.


IPv4: Late 80s/Early IPv4: Late 80s/Early 90s90s

• Hosts went from 10,000 to 100,000 between 1987 to 1989.

• IP space was classful:−126 class A of 16M hosts,−16K class B of 64K,− 2M class C of 253.

• Concern about routing and addressing.

• By 1993, people reckoned there was < 1year worth of address space left.

• Lead to CIDR: Classless Interdomain Routing.


CIDRCIDR

• Class A, B and C had network/host boundary.• CIDR puts the boundary on any bit.

Net First

Address

Net Mask Prefix

Length

MIT 18.0.0.0 255.0.0.0 /8

TCD 134.226.0.

0

255.255.0.

0

/16

School

s

87.32.0.0 255.240.0.

0

/12


NANATT

• Connection from private block is made.

• Allocate public address/ports, record in rules.

• Outgoing packets have private address and port

replaced.

• Incoming packets have public address and port

replaced.

Network Address Translation made it possible to use fewer addresses. Idea: rewrite addresses using rules. Allows use of private address space.


IPv4 IPv4 TodayToday

• NAT/CIDR have bought IPv4 (too much?) time.

• IPv4 has developed new problems since.

• Security (spam, viruses, botnets, exploits, …)

• Routing (scalability, stability, multihoming)

• NAT (inhibitor, robustness, performance, cost)

• Politics/Market (scarce resources, must be (seen

to be?) distributed fairly)


IPv6IPv6

• OSI 7 Layer Model.

• TCP/IP spans many layers.

• IP is layer 3.

• IPv6 is a new layer 3.

• So we keep TCP, UDP, HTTP, …

• Need to update the glue between layers

too.


Major Major ChangesChanges

• Bigger addresses (128 bit up from 32 bit).

• Better extensibility (extension headers).

• Built in autoconfiguration (DHCP/PPP still

possible).

• Mandatory IPsec.

• More integrated multicast.

• ARP replaced with Neighbour Discovery.


IPv6 Addressing (format, IPv6 Addressing (format, types and policy)types and policy)


AddresseAddressess

• Compromise between variable and 64 bit.

• 128 bit addresses: 340282366920938463463374607431768211456.

• In practice you loose space to structure.

• 64 bits for hosts: enough for biggest subnets?

• 64 bits for networks: enough to make aggregation easier ?•Long, so written in 8 hex quads.

•Shortcuts permitted.


Example Example AddressAddress

• 2001:0db8:0010:0300:0000:0000:0ae2:510b−Long version.

• 2001:db8:10:300:0:0:ae2:510b−Omit leading zeros.

• 2001:db8:10:300::ae2:510b−Replace run of zeros with ::

• 2001:db8:10:300::10.226.81.11−Can write end as IPv4 address.


Structured Structured AddressingAddressing

• 2001::/16 Chunk of production address space

• 2001:770::/32 = HEAnet (ISP prefix)

• 2001:770:10::/48 = TCD (organisation prefix)

• 2001:770:64:300::/56 = Maths (dept prefix)

• 2001:770:64:301::/64 = Wireless (subnet)

This structure is dictated by policy at various levels, rather than being hardwired Into the protocol. This allows the policy to be adjusted to balance the needs of various stakeholders (users, network administrators, ISPs, governments, hardware/software vendors, …)


Special Special AddressesAddresses

• :: the unspecified address.

• ::1 localhost/loopback.

• fe80::/10 link-local addresses.

• ff00::/8 multicast addresses.

• Multiple addresses on each network card on

each machine now normal!


How IPv6 interacts with How IPv6 interacts with other layers.other layers.


Communication Communication ModesModes

• Unicast: Destined to a single machine (normal).

• Broadcast: Destined to all machines (ARP).

• Multicast: Destined to all in a particular group (IP

TV, ND).

• Anycast: Destined to any one of a particular

group (DNS Root Servers, 6to4).


AutoconfiguratiAutoconfigurationon

• Generate host-id and form link-local.

• Check link-local is unique.

• Now we can talk IPv6.

• Multicast router solicitation to get prefix(es).

• Global address(es) = prefix(es) + host-id.

• Do duplicate address detection.

• Doesn’t have to be used: manual, DHCPv6, PPP and privacy addressing also possible.


Address Address ScopeScope

• Might have same link-local address on each interface.

• How do we know which one?

• Addresses can have scope.

• E.g. two interfaces eth0 and eth1

• fe80::2b0:d0ff:fef4:c6c5%eth0

• fe80::2b0:d0ff:fef4:c6c5%eth1

• No need for scope on global addresses.


Header Header DifferencesDifferences

• Bigger addresses.

• Drop uncommonly used features (fragments, IP options).

• Drop fields that are redundant (header length, checksum).

• Rename some fields to better represent modern usage.

• 64 bit alignment to help hardware guys.

• Add a new flow label.


Header Header FlexibilityFlexibility

• Main header is for forwarding packet.

• Minimum necessary fields included.

• New types of header may be chained together

leading to TCP, UDP or ICMP.

• Used for mobility, security, tunnels, and other

advanced features.


GlueGlue

• ICMP closely linked with IP, so new ICMPv6.

• ICMPv6 includes Neighbour Discovery to replace ARP.

• Most layer 2 glue is included in details of neighbour discovery.

• Changes to higher layers relatively small.

• TCP/UDP “pseudo-header” for checksums.

• Update protocols that embed IPv4 addresses.


Transition MechanismsTransition Mechanisms


Transition Transition MechanismsMechanisms

• We have a large IPv4 network.

• We want a large IPv6 network.

• IPv4 only hardware, software and people.

• How to get IPv6 working around this?

• A lot of effort on Transition Mechanisms.


Transition Transition MechanismsMechanisms

• Several broad strategies.

• Dual stack: run both IPv4 and IPv6.

• Tunnelling: hide IPv6 inside IPv4/UDP/…

• Translation: convert IPv6 into IPv4.

• Proxies: Someone speaks IPv6 on your behalf.

• Too many to discuss all.


Transition Transition ExamplesExamples

• Vista/OS X/Linux/BSD all run dual-stack.

• Point-to-point tunnels to get around legacy equipment.

• Automagic tunnelling (6to4, Teredo) for end users in IPv4 only networks.

• Proxies already common (web proxy, DNS server, SMTP server, …)

• Translation uncommon, maybe for legacy apps?


The current state of IPv6.The current state of IPv6.


Potted Local Potted Local HistoryHistory

• 1999-2001: Small scale academic experiments.

• 2002: Native gigabit IPv6 from HEAnet to TCD.

• 2003: IPv6 addresses in .ie zone.

• 2004: IPv6 server for .ie zone.

• 2005: National IPv6 centre established.

• 2006: 6bone retired in favour of full IPv6 net.

• 2007: ???


IPv6 IPv6 TodayToday

• The basics are done.

• Deployment underway, not yet widespread.

• Core/edge ready, corporate/ISP waiting.

• Policy/standards continuing to evolve.

• Considering IPv6 in lifetime of current planning,

projects & purchases considered prudent.


SummarSummaryy

• IPv6 just replaces IP layer in TCP/IP.

• Fixes problems, particularly addressing.

• Eases features such as mobility, security, …

• Transition mechanisms to help deployment.

• Standards, policy and network in place.

• Someway to go before full deployment.

• Continuing to evolve as living protocol.


AcknowledgemAcknowledgementsents

This presentation includes some material originally developed for presentations at Doolin Tech Talks, RIPE, HEAnet and TCD.


ContactContact

Mícheál Ó Foghlú

Research Director

Telecommunications Software & Systems Group

Waterford Institute of Technology

Cork Road

Waterford

Ireland

+353 51 302963 (w)

[email protected]

http://www.tssg.org

http://www.ofoghlu.net/log (Personal Blog)

mailto:[email protected]

http://www.tssg.org/

http://www.ofoghlu.net/log


Further Further InformationInformation

Web Sites:

• National Irish IPv6 Centre http://www.ipv6-ireland.org

• Irish IPv6 Task Force http://www.ipv6.ie

• IPv6 ePrints Server (Public Documents) http://www.6journal.org/

• IPv6 Dissemination (Public Training) http://www.6diss.org/tutorials/

Individual Documents/Presentations:

• http://arstechnica.com/articles/paedia/IPv6.ars/1 (Iljitsch van Beijnum, 7th March 2007)

• http://bgp.potaroo.net/ipv4/ (Geoff Huston APNIC, 2006)

• http://www.6journal.org/archive/00000261/02/

WWC_IPv6_Forum_Roadmap__Vision_2010_v6.pdf (IPv6 Forum Roadmap & Vision,

2006)

• http://colab.cim3.net/file/work/Expedition_Workshop/2005-12-

06_Advancing_Information_Sharing_And_Data_Architecture/IPV6/NIST%20ipv6-doc-eai-

v4%2012062005.ppt (Doug Montgomery NIST, 2005)

http://www.ipv6-ireland.org/


Further Further InformationInformation

Individual Documents/Presentations Contd:

• MIPv6 Linux Software ( MIPL )− www.mobile-ipv6.org

• MIPv6 IETF charter− http://www.ietf.org/html.charters/mip6-charter.html


Thank you!Thank you!

This presentation has been shared under the Creative Commons Attribution 2.0 UK:

England & Wales Licence (http://creativecommons.org/licenses/by/2.0/u

k)by the Irish IPv6 Task Force

(http://www.ipv6.ie)

Please acknowledge this source if you use it for free or for profit

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