How To Transition From Ipv4 To Ipv6 (Ipv6) (Ipvin4) (Iplv6/Ipv4)

Transcription

1 Guide to TCP/IP Fourth Edition Chapter 10: Transitioning from IPv4 to IPv6: Interoperation

2 Objectives Describe the various methods that allow IPv4 and IPv6 networks to interact, including dual stack and tunneling through the IPv4 cloud Explain hybrid IPv4/IPv6 network and node types, such as basic hybrid, nested hybrid, and true hybrid Explain how an IPv6 transition address works Describe the various IPv4/IPv6 transition mechanisms, such as dual stacks and IPv6-over- IPv4 tunneling 2

3 Objectives (cont'd.) Describe the different tunneling configuration types and their device interactions Explain the ISATAP tunneling mechanism, including its components, addressing, and routing and router configuration Explain the 6to4 tunneling mechanism, including its components, addressing and routing, and communication procedures Explain the Teredo tunneling system, including its components, addressing and routing, and processes 3

4 How Can IPv4 and IPv6 Interact? IPv6 and IPv4 will probably exist side by side for many years Designers of IPv6 anticipated a slow cutover Created a set of techniques to allow IPv6 to function adequately in a world dominated by IPv4 4

5 Dual-Stack Approach Dual-stack Implementations for individuals or small offices may work as experiments However, they are limited by the availability of dual stack routers at ISPs at the edge of the Internet Most important dual stack machines Will be the routers themselves Dual-stack router Can provide a connection between the IPv4 Internet and an office that already made the switch to IPv6 5

6 Tunneling through the IPv4 Cloud Internet Will probably move to IPv6 from the edges in IPv6 will be adopted First by smaller organizations with greater flexibility and higher tolerance for difficulties of pioneering IPv6 packet is formed normally Sent to a router capable of encapsulating it in an IPv4 packet 6to4 tunneling method Alternate scheme specified in RFC

7 IPv6 Rate of Adoption Biggest push for the adoption of IPv6 Coming from those who were not a part of the initial Internet land rush of the 1990s Makers of technologies (cellular phones and smartphones) have two reasons to embrace IPv6 They want the address space Communications technologies need the improved functionality of the IPv6 protocol suite 7

8 Transitioning to IPv6: The Reality Reaction of industry participants to potential of IPv6 Initially, service provider segment of the market pushed for the protocol Router and switch vendors saw the protocol as a marketing opportunity Engineers in the service provider space saw IPv6 as a solution to solve a specific problem 8

9 Interoperability One technology can work together with another technology Network address translation (NAT) Used to provide translation between private IP addresses and public IP addresses Transitioning to IPv6 The movement of deploying IPv6 throughout a production environment 9

10 Network Elements Network elements and software tools Clients Servers Routers Gateways VoIP networks Network management nodes Transition nodes Firewalls 10

11 Software Tools and utilities designed to monitor, report on, and manage network infrastructure elements Network management utilities Network Internet infrastructure applications Network systems applications Network end-user applications Network high-availability software Network security software 11

12 Transitioning to IPv6 from the Windows Perspective Microsoft provides support for IPv6 implementations for: Windows Server 2008 Windows Vista Windows 7 Microsoft Supports the Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) 12

13 Availability Most of the IPv6 deployments are: In Asia and Europe In areas that were behind the deployment of IPv4 infrastructures These environments are ahead of the curve for two reasons Market is forcing IPv6 onto the consumers, which creates demand for provider support A lot of the solutions are deployed initially with IPv6 13

14 The IPv6 Address Space IPv6 solves address shortage problem by: Creating address space that is more than 20 orders of magnitude larger than IPv4 s address space IPv6 address space Provides hierarchy in a flexible and well-articulated fashion with room for future growth 14

15 What s Next? Major obstacle Convincing executive managers to deploy an IPv6 solution Major event that may accelerate the deployment of IPv6 Announcement that the Department of Defense (DoD) will be IPv6 ready by

16 Hybrid IPv4/IPv6 Networks and Node Types As software and hardware components are upgraded IPv6 devices will need to be able to talk to each other over an IPv4 infrastructure Mixed environments are called hybrid networks 16

17 Basic Hybrid Network Model 17

18 Nested Hybrid Network Model 18

19 True Hybrid Network Model 19

20 IPv6 Transition Addresses IP address parser Attempts to translate an IPv4 address into its IPv6 equivalent Transition address methods Using literal IPv6 addresses in URLs Stateless IP/ICMP translation algorithm (SIIT) 20

21 Transition Mechanisms Methods and address types that provide for communication between network nodes That use only IPv4 or only IPv6 to interact with each other or with network resources Transition from IPv4 to IPv6 requires multiple stages 21

22 Dual Protocol Stacks for IPv4 and IPv6 Implemented at the level of the device s operating system Dual-stack implementations use special addressing Most modern operating systems have IPv6 enabled by default Dual stack and dual layer Different types of architecture 22

23 Dual-IP-Layer Architecture Has both IPv4 and IPv6 protocols operating in a single Transport layer implementation 23

24 Dual-IP-Layer Architecture (cont d.) 24

25 Dual-Stack Architecture Maintains separate stacks at both the Network and Transport layers 25

26 Dual-Stack Architecture (cont d.) 26

27 Dual Architecture and Tunneling Dual-architecture nodes Can produce either IPv4 or IPv6 packets and forward them to a gateway router Need two network interfaces, one for IPv4 and the other for IPv6 27

28 IPv6-over-IPv4 Tunneling Used to allow IPv6 network nodes to send packets over an IPv4 network infrastructure Presents a challenge for IPv6 header construction Source node determines which packets must be encapsulated Based on the routing information the node maintains in its own routing table 28

29 IPv6-over-IPv4 Tunneling (cont d.) 29

30 DNS Infrastructure DNS records and DNS name resolution management Handled differently for IPv4 and IPv6 DNS servers must be configured for dual stack Supporting both A and AAAA records In mixed IPv4/IPv6 environments DNS resolver libraries on network nodes must have the ability to manage both A and AAAA records 30

31 Tunneling Configurations for Mingling IPv4 and IPv6 Tunneling mechanism configurations Defined by RFC 4213 Encapsulator Node at the sending end of the tunnel Decapsulator Receiving node at the other end of the tunnel 31

32 Router-to-Router Requires specifically configured end points to the tunnel 32

33 Host-to-Router and Router-to-Host Represents the first and last legs of a packet s trip from source to destination Figure Host-to-router and router-to-host tunnels 33

34 Host-to-Host Two IPv6 nodes are linked directly using a tunnel over an IPv4 network infrastructure 34

35 Types of Tunnels RFC 2893 originally specified two different tunneling types Configured and automatic RFC 4213, which made RFC 2893 obsolete Removed references to automatic tunneling Configured tunnels Require that end point addresses be determined in the encapsulator device From configuration data stored for each tunnel 35

36 ISATAP Intra-Site Automatic Tunnel Addressing Protocol (ISATAP) Used to connect dual-stack IPv4/IPv6 devices across IPv4 network infrastructures Routing and Addressing in Networks with Global Enterprise Recursion (RANGER) Builds on ISATAP to include IPv6 autoconfiguration 36

37 Overview Implements router-to-host, host-to-router, and hostto-host address assignments Supported on Windows Vista, Windows 7, Windows Server 2003, and Windows Server 2008 ISATAP IPv6 automatic tunneling Can be used in domains that adhere to security specifications found in RFC 5214 ISATAP nodes Must observe functionality requirements for IPv6 computers found in RFC

38 ISATAP Components 38

39 Router Discovery for ISATAP Nodes ISATAP interfaces Use neighbor discovery mechanisms described in RFC 4861 Because of the lack of multicast support Automatic router discovery cannot be used ISATAP hosts use PRLs to maintain current information about ISATAP routers 39

40 ISATAP Addressing and Routing ISATAP addresses use the locally administered interface identifier Windows 7 or Windows Server 2008 computers Are automatically assigned ISATAP addresses Each device involved in communicating on or off an ISATAP network Uses different routes to direct traffic from source to destination nodes Devices and routers from other subnets need routes to send traffic to the ISATAP logical subnet 40

41 ISATAP Addressing and Routing (cont d.) 41

42 ISATAP Communications ISATAP node uses host-to-host tunneling ISATAP host communicating with an IPv6 node on an IPv6-capable subnet involves two different connections Host-to-router tunnel Connection between ISATAP router and IPv6- capable subnet 42

43 Configuring an ISATAP Router Windows Vista/7/Server 2008 computers Can be configured as ISATAP routers ISATAP configuration is performed at the command prompt 43

44 Configuring an ISATAP Router (cont d.) Insert Figure here (image quality is really poor) 44

45 6to4 IPv4-to-IPv6 transition technology Allows IPv6 packets to be sent across IPv4 network infrastructures, including the IPv4 Internet RFC 3056, current documentation Assigns an interim and unique IPv6 address prefix to any site that already possesses IPv4 addresses Specifies encapsulation method for sending IPv6 packets over IPv4 using the unique prefix address 45

46 Overview Avoids the need to configure the distinct tunnels required by ISATAP Applied to a network node or to a local network 6to4 addressing on an IPv6 network employs autoconfiguration Uses the last 64 bits as the host address and the first 64 bits as the IPv6 prefix 6to4 issues Large numbers of misconfigured nodes Poor network performance 46

47 6to4 Components 47

48 6to4 Addressing and Routing Any 6to4 site must possess at least one valid globally unique 32-bit IPv4 address 6to4 gateway router directly attached to the Internet Receives an IPv4 address assignment from a service provider Address represents the site address 6to4 network devices use on-link and default routes 6to4 relay uses on-link route on its tunneling interface to perform router-to-router communication 48

49 6to4 Communication Communication models in a 6to4 infrastructure Node-to-node/router Node-to-node Communication between 6to4 node and IPv6 host must go From sending node to router From router to relay From relay to receiving node 49

50 Using ISATAP and 6to4 Together Normally, an ISATAP host could not receive advertisements from a 6to4 router 6to4 router could also be manually configured as an ISATAP router ISATAP node then configures a default route to the 6to4 router in order to send traffic 50

51 Teredo IPv4-to-IPv6 transition technology Allows IPv6 connections between two IPv6 network nodes across an IPv4 network infrastructure Can operate from behind home routers and broadband devices Using network address translation (NAT) Developed by Microsoft Formally standardized by RFC

52 Overview Teredo service tunnels IPv6 packets over IPv4 UDP Using Teredo servers and Teredo relays Teredo servers are stateless Responsible for managing only small amounts of traffic between Teredo client computers Teredo relays Perform IPv6 routing between the Teredo service and IPv6-capable networks 52

53 Teredo Components Essential components of a Teredo system Teredo client Teredo server Teredo relay, Teredo host-specific relay 53

54 Teredo Addressing and Routing Teredo addresses are made up of five components: Prefix Server IPv4 Flags Port Client IPv4 Like other IPv4/IPv6 transition mechanisms Teredo uses online and default routes 54

55 Teredo Processes 55

56 Summary During the transition from IPv4 to IPv6, there will be a lengthy period of time when both protocols exist side by side Several different IPv4/IPv6 hybrid networks and nodes can be used to facilitate the transition Transition mechanisms can use a dual-ip-layer architecture or a dual-stack architecture IPv6-over-IPv4 tunneling involves different device configurations 56

57 Summary (cont'd.) ISATAP is an automatic tunneling mechanism that allows IPv6 ISATAP network nodes to communicate across an IPv4 network 6to4 is an IPv4-to-IPv6 transition technology characterized by its ability to allow IPv6 packets to be sent across IPv4 networks and the use of relay servers Teredo is another IPv4-to-IPv6 transition technology characterized by its unique ability to operate behind routers and broadband devices with NAT enabled 57