Transitioning to IPv6

April 15,2005

Presented By:

Richard MoorePBS Enterprise Technology

Agenda

> Benefits of IPv6> What is IPv6?> IPv6 Operation> IPv6 Deployment> IPv6 Challenges> Resources

Improved Routing Efficiency

> IPv6’s large addressing space> Multi-level address hierarchy> Reduces the size of Internet routing tables> All fields in the IPv6 header are 64 bit aligned

Network Prefix Interface ID

128 bits

XXXX = 0000 through FFFF

xxxx xxxx xxxx xxxx xxxx xxxx xxxx xxxx

Supports Autoconfiguration

> Accommodates mobile services> Accommodates Internet capable appliances> Decreases complexity of network discovery> Simplifies renumbering of existing networks> Simplifies transition between networks

Embedded IPsec

> IPsec is a mandatory part of IPv6 protocol> Protocol provides security extension headers> Eases implementation of encryption,

authentication, and VPN> Provides end-to-end security

Support for Mobile IP and Mobile Computing Devices

> Allows mobile devices to move without breaking existing connections

> Care-of-Address eliminates need for foreign agents

> Simplifies communication of Corresponding nodes directly with Mobile nodes

Elimination of Network Address Translation (NAT)

> NAT is a mechanism to share or reuse the same address space among different network segments

> NAT places a burden on network devices and applications to deal with address translation

Supports Widely Deployed Routing Protocols

> Extended support for existing Interior Gateway Protocols and Exterior Gateway Protocols

> For example: OSPFv3, IS-ISv6, RIPng, MBGPv4+

Improved Support for Multicast

> Replaces IPv4 broadcast functionality> Improves network efficiency

IPv6 Header FormatIPv4 Header IPv6 Header

Version IHLType ofService

Total Length

FlagsFragment

OffsetIdentification

Time toLive

ProtocolHeader

Checksum

Source Address

Destination Address

Options Padding

Version TrafficClass

Flow Label

Payload Length NextHeader

HopLimit

Source Address

Destination Address

> IPv6 header is streamlined for efficiency> Greater flexibility to support optional features

IPv6 Extension Headers

> Extension header is optional> 64 bit aligned, lower overhead> No size limit as with IPv4> Processing only by destination node.> Next header field identifies the extension header

IPv6 Addressing

> 128-bit address is separated into eight 16-bit hexadecimal numbers

> For example:2013:0000:1F1F:0000:0000:0100:11A0:ADFF

IPv6 Addressing

> Conventions are used to represent IPv6 addresses> Leading zeros can be removed, 0000 = 0

(compressed form)> “::” represents one or + groups of 16 bits zeros> For example:

2001:0:13FF:09FF:0:0:0:0001 = 2001:0:13FF:09FF::1

IPv6 Addressing

> Lower four 8 bits can use decimal representation of IPv4 addresses

> For example:0:0:0:0:0:0:192.168.0.1

> IPv6 node allows more than one type of IP address

Unicast & Global Unicast Addressing

> Unicast: An address used to identify a single interface

> Global Unicast: An address that can be reached and identified globally

3 bits

Global Routing Prefix Subnet ID Interface ID

001

45 bits 16 bits 64 bits

128 bits

Provider Site Host

Global Unicast Address Format

Site-local Unicast Addressing

> An address that can only be reached and identified within a customer site

> Similar to IPv4 private address

1111111011 Subnet ID

Interface ID

FEC0::/10

0

10 bits

16 bits

64 bits

128 bits

Site-local Unicast Address Format

Link-local Unicast Addressing

> An address that can only be reached and identified by nodes attached to the same local link.

Interface ID0

64 bits

128 bits

Link-local Unicast Address Format10 bits

FE80::/10

1111111010

Anycast Addressing

> A global address that is assigned to a set of interfaces belonging to different nodes

> Must not be used as source address of IPv6 packet> Must not be assigned to an IPv6 host

Subnet ID 00000000000000000000

N bits 128 – N bits

128 bits

Anycast Address Format

Multicast Addressing

> Address assigned to a set of interfaces belonging to different nodes

Group ID

F F Flag Scope

1111 1111

8 bits 8 bits

112 bits

128 bits

Flag0 if permanent1 if temporary

1 = interface – local2 = link – local3 = subnet – local4 = admin – local5 = site – local8 = organization – localE = global

Scope

Multicast Address Format

Neighbor Discovery

> Determines link-layer address of neighbor on the same network

> Determines the link-layer address of another node on the same local link

> Advertisement messages are also sent when there are changes in link-layer addressing of a node on a local link

Router Discovery

> Discovers routers on local link using advertisements and solicitation messages

> Determines type of autoconfiguration a node should use

> Determines Hop limit value> Determines network prefix> Determines lifetime information> Determines default router

Stateless Autoconfiguration and Renumbering of IPv6 Nodes

> Stateless autoconfiguration uses network prefix information in router advertisement messages

> Remaining 64 bits address is obtained by the MAC address assigned to the Ethernet interface combined with additional bits in EUI-64 format

> Renumbering of IPv6 nodes is possible through router advertisement messages containing old and new prefix

Path Maximum Transfer Unit (MTU)

> IPv6 routers do not handle fragmentation of packets

> Uses ICMP error reports to determine packet size matching MTU size

> Allows a node to dynamically discover and adjust differences in MTU size

DHCPv6 and DNS

> Supports stateful configuration with DHCPv6> Node has option to solicit an address via DHCP

server when a router is not found> DHCPv6 is similar to DHCPv4> DHCPv6 uses multicast for messaging> New record type to accommodate IPv6

addressing in DNS

Dual-stack Backbone

> All routers maintain both IPv4 and IPv6 protocol stacks

> Applications choose between using IPv4 or IPv6> All routers in the network must be upgraded to

IPv6> All routers must have sufficient memory for both

IPv4 and IPv6 routing tables

IPv6 over IPv4 Tunneling

> Encapsulates IPv6 traffic within IPv4 packets

IPv6 over IPv4

Tunnel

TunnelEntry Node

TunnelExit Node

IPv6 IPv6

Original Packet Tunnel Packet

Source of original packet

IPv4/IPv6Dual stack

IPv4/IPv6Dual stack

Destination oforiginal packet

Original Packet

Tunnel Packet

IPv6Header

TransportHeader

IPv6Payload

IPv6Header

TransportHeader

IPv6Payload

IPv4Header

IPv6 over IPv4 Tunneling

Manually Configured Tunnels

> Defined by RFC 2893, both end points of tunnel must be configured with appropriate IPv6 and IPv4 addresses

> Edge routers will forward tunneled traffic based on the configuration

GRE Tunnels

> GRE allows one network protocol to be transmitted over another network protocol

> Packets are encapsulated to be transmitted within GRE packets

> GRE is an ideal mechanism to tunnel IPv6 traffic

IPv4 Compatible Tunnels

> Defined in RFC 2893, tunnel mechanisms automatically set up tunnels based on IPv4-compatible IPv6 addresses

> IPv4-compatible IPv6 address defines the left-most 96 bits as zero, followed by an IPv4 address

> For example:0:0:0:0:0:0:64.29.51.26

6to4 Tunnels

> Defined by RFC 3056, 6to4 tunneling uses an IPv4 address embedded in the IPv6 address

> Identifies the end point and configures tunnel automatically

2002 IPv4 Address Subnet Interface ID

16 bits 32 bits 16 bits 64 bits

6to4 Tunneling Address Format

ISATAP Tunnels

> ISATAP tunneling is similar to 6to4 tunneling> Designed for use in a local site or campus

network

Subnet Prefix 00005EFE IPv4 Address

ISATAP Tunneling Address Format

64 bits 32 bits 32 bits

Teredo Tunnels

> Provides address assignment and host-to-host automatic tunneling for unicast IPv6 connectivity across the IPv4 Internet when IPv6/IPv4 hosts are located behind one or multiple IPv4 NATs.

> To traverse IPv4 NATs, IPv6 packets are sent as IPv4-based User Datagram Protocol (UDP) messages.

Teredo Prefix Teredo ServerIPv4 Address

FlagsObscured

External PortObscured

External Address

32 bits 32 bits 16 bits 16 bits 32 bits

Teredo Tunneling Address Format

MPLS Tunnels

> Isolated IPv6 domains can communicate with each other over MPLS IPv4 core networks

> MPLS forwarding is based on labels rather than IP headers requiring fewer infrastructure upgrades or reconfigurations

> Allows IPv6 networks to be combined into VPNs or extranets over IPv4 VPN infrastructure

IPv6 Challenges

Q11996 - 2001

2002 2003 2004 2005 20062007 - 2010

Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q1Q2 Q2Q3 Q3Q4 Q4

Early Adopters

Application Port <= Duration 3+ Years =>

ISP Adoption <= Duration 3+ Years =>

Consumer Adoption <= Duration 5+ Years =>

Enterprise Adoption <= Duration 5+ Years =>

IPv6 Transition

Early Adopters: Europe, Japan, China, North America IPv6 Task Force

Resources

> Questions or Comments?rmoore@pbs.org