1. Coexistence and Migration
Lesson 11
Coexistence and Migration

2. Lesson Objectives Coexistence and migration overview
Coexistence mechanisms
Tunneling configurations
6over4
6to4
ISATAP
PortProxy
Migrating to IPv6

3. Coexistence and Migration Overview
The transition from IPv4 to IPv6 will take years
Some hosts will use IPv4 indefinitely
Migration is the long term goal, coexistence in the interim
Transition criteria:
Existing IPv4 hosts can be upgraded at any time independent of the upgrade of other hosts or routers
New hosts using only IPv6 can be added at any time without dependencies on other hosts or routing infrastructure
Existing IPv4 hosts with IPv6 installed can continue to use their IPv4 address and do not need additional addresses
Little preparation is needed to upgrade existing IPv4 nodes to IPv6 or to deploy new IPv6 nodes

4. Node Types IPv4-only node IPv6-only node IPv6/IPv4 node IPv4 node

5. Compatibility Addresses
IPv4-compatible addresses
::w.x.y.z
IPv4-mapped addresses
::FFFF:w.x.y.z
6over4 addresses
Interface ID of ::WWXX:YYZZ
6to4 addresses
Prefix of 2002:WWXX:YYZZ::/48
ISATAP addresses
Interface ID of ::0:5EFE:w.x.y.z

6. Coexistence Mechanisms
Dual IP layer
IPv6 over IPv4 tunneling
DNS infrastructure

7. Dual IP Layer Architecture
Application
Layer
Transport Layer (TCP/UDP)
IPv6
IPv4
Network
Interface Layer

8. Dual Stack Architecture
Application
Layer
TCP/UDP
TCP/UDP
IPv6
IPv4
Network
Interface Layer

9. IPv6 over IPv4 Tunneling IPv6 Packet IPv6 Header Extension Headers
Upper Layer Protocol Data Unit
IPv4 Header
IPv6 Header
Extension
Headers
Upper Layer Protocol Data Unit
IPv4 Packet

10. DNS Infrastructure Address records Pointer records
A records for IPv4 nodes
AAAA records for IPv6 nodes
Pointer records
PTR records in IN-ADDR.ARPA domain for IPv4 nodes
PTR records in IP6.INT domain for IPv6 nodes
Address selection rules
Choosing the “best” set of addresses with which to communicate

11. Tunneling Configurations
Router-to-Router
Host-to-Router and Router-to-Host
Host-to-Host

12. Router-to-Router Tunneling
IPv4 Infrastructure
IPv4 or IPv6
Infrastructure
IPv4 or IPv6
Infrastructure
IPv6 over IPv4 Tunnel
IPv6
Node
IPv6
Node
IPv6/IPv4 Router
IPv6/IPv4 Router

13. Host-to-Router and Router-to-Host Tunneling
IPv4 Infrastructure
IPv4 or IPv6
Infrastructure
Node A
Node B
IPv6 over IPv4 Tunnel
IPv6/IPv4
IPv6
IPv6/IPv4 Router

14. Host-to-Host Tunneling
IPv4 Infrastructure
IPv6 over IPv4 Tunnel
IPv6/IPv4
Node
IPv6/IPv4
Node

15. Types of Tunnels Configured Automatic IPv6 Automatic Tunneling
Manual configuration of tunnel endpoints
Automatic
Tunnel endpoints determined from use of logical tunnel interfaces, routes, and source and destination IPv6 addresses
IPv6 Automatic Tunneling
Uses IPv4-compatible addresses

16. 6over4 Overview
Host-to-host, host-to-router, and router-to-host automatic tunneling technology
6over4 address:
[64-bit prefix]::WWXX:YYZZ
Link-local 6over4 address FE80::WWXX:YYZZ
6over4 treats an IPv4 multicast-enabled infrastructure as a single multicast-capable link
Used for unicast and multicast IPv6 traffic over an IPv4 infrastructure

17. IPv4 Multicast-Enabled
6over4
Host B
IPv4 Multicast-Enabled
Infrastructure
Host A
IPv6 Infrastructure
6over4
Host
IPv6 over IPv4 Tunnel
6over4
Host
IPv6/IPv4
Router
Logical
Equivalent
Host B
IPv6 Infrastructure
IPv6/IPv4
Router
Host A

18. Source and Target Link-Layer Address Options for 6over4
Type
Length
Address
= 1
Zero
IPv4 Address

19. 6to4 Overview
Address assignment and router-to-router automatic tunneling technology
6to4 address:
2002:WWXX:YYZZ:[SLA ID]:[Interface ID]
6to4 treats the IPv4 Internet as a single link
Used for unicast traffic over the IPv4 Internet

20. 6to4 Components IPv6 Internet Internet 6to4 Relay Router IPv6 Host D
IPv6/IPv4
IPv6
Internet
IPv6 Host D
IPv6-only
6to4 Host C
IPv6/IPv4
Internet
Site 2
6to4 Router
IPv6/IPv4
6to4 Router
IPv6/IPv4
6to4 Host A
IPv6/IPv4
6to4 Host B
IPv6/IPv4
Site 1

21. 6to4 Support in Windows
With public IPv4 address, automatic configuration as a 6to4 host/router
Able to communicate with other 6to4 sites
Able to communicate with IPv6 Internet
With ICS, automatic configuration as a 6to4 router
Enables forwarding
Sends routing advertisements with 6to4 prefixes
SLA ID = Interface index of intranet interface

22. 6to4 for Windows IPv6 Internet Internet 6to4 Relay Router IPv6 Host D
IPv6/IPv4
IPv6
Internet
IPv6 Host D
IPv6-only
6to4 Host C
IPv6/IPv4
Internet
Site 2
Site 3
6to4 Router
IPv6/IPv4
6to4 Host/Router E
IPv6/IPv4
6to4 Router
IPv6/IPv4
6to4 Host A
IPv6/IPv4
6to4 Host B
IPv6/IPv4
Site 1

23. ISATAP Overview
Address assignment and host-to-host, host-to-router, and router-to-host automatic tunneling technology
ISATAP addresses:
[64-bit prefix]:0:5EFE:w.x.y.z
ISATAP treats an IPv4 infrastructure as a single link
Used for unicast traffic across an IPv4 intranet

24. Link-Local ISATAP Configuration
ISATAP Host A
FE80::5EFE:
IPv4
Infrastructure
ISATAP Host B
FE80::5EFE:

25. ISATAP Router Configuration
Example prefix: 3FFE:2900:D005:7::/64
IPv6
network
IPv4
Infrastructure
ISATAP
Router
IPv6 over IPv4 Tunnel
ISATAP Host B
3FFE:2900:D005:7:5EFE:
ISATAP router
Responds to tunneled router solicitations from ISATAP hosts
Forward traffic between ISATAP hosts and other IPv6 subnets

26. ISATAP and 6to4 Example IPv4 Infrastructure Internet ISATAP Host A
Internet
ISATAP Host B
2002:836B:1:2:0:5EFE:
IPv4
Infrastructure
ISATAP Host A
2002:9D36:1:2:0:5EFE:
Part 3
Part 2
Part 1
6to4 Router A
IPv6/IPv4
6to4 Router B
Site A
Site B

27. PortProxy Service TCP proxy for: IPv4 to IPv4 IPv4 to IPv6
IPv4-only host can communicate with IPv6-only server or application
IPv6 to IPv6
IPv6 to IPv4
Use to “IPv6-enable” IPv4-only applications running on a Windows .NET Server computer

28. PortProxy Coexistence Scenarios
An IPv4-only node can access an IPv6-only node
An IPv6-only node can access an IPv4-only node
An IPv6 node can access an IPv4-only service running on an IPv6/IPv4 node

29. Migrating to IPv6
1. Upgrade your applications to be independent of IPv4 or IPv6
2. Update the DNS infrastructure to support IPv6 addresses and PTR records
3. Upgrade hosts to IPv4/IPv6 nodes
4. Upgrade routing infrastructure for native IPv6 routing
5. Convert IPv4/IPv6 nodes to IPv6-only nodes

30. Review Coexistence and migration overview Coexistence mechanisms
Tunneling configurations
6over4
6to4
ISATAP
PortProxy
Migrating to IPv6