IPv4 - IPv6 Integration and Coexistence Strategies Warakorn Sae-Tang Network Specialist Professional Service Department A Subsidiary of G-Able The communication Solution Company Limited

2 Objective  Describe following strategies for the deployment of IPv6: Deploying IPv6 over Dual Stack Backbones Deploying IPv6 over IPv4 Tunnels Deploying IPv6 over Dedicated Data Links Deploying IPv6 over MPLS Backbone Deploying IPv6 using Protocol Translation Mechanisms

3 IPv6 Applications.  Mobile IP (Mobile IPv6)  Internet-enable Appliances  Internet-enable Automobiles  Internet-enable ATMs  Smart Sensor  etc.

4 Transition in IPv6  When moving to another technology, the transition has to be discussed and is generally very important. Often it is where most of the money is put.  Many new technologies didn’t succeed because of lack of transition scenarios/tools.  IPv6 was designed, at the beginning, with transition in mind: no D day.  IPv6 is transition-rich, as you will see.

5 Transition Mechanisms  The four key strategies for deploying IPv6 are as follows: Deploying IPv6 over Dual-Stack Backbones Deploying IPv6 over IPv4 Tunnels Deploying IPv6 over Dedicated data links Deploying IPv6 over MPLS backbones IPv6 Network IPv4 Network

6 Using IPv4-IPv6 Protocol Dual Stack Devices  Basic strategy for routing both IPv4 and IPv6  Require network devices such as routers and end system running both IPv4 and IPv6 protocol stacks.  Applications that are not upgraded to support IPv6 stack can coexist with upgraded applications on the same end system.  DNS resolver returns IPv6, IPv4 or both to application.

7 IPv4-IPv6 Dual Stack Support IPv4 only Support dual IPv4 and IPv6

8 IPv4-IPv6 Dual Stack Operation DNS Server 3ffe:b00:: Web Server 3ffe:b00::1 IPv4 Network IPv6 Network

9 1. Deploying IPv6 Using Dual Stack Backbones  With the dual stack backbone deployment, all routers in the network need to be upgraded to be dual stack.  Application choose between using IPv4 or IPv6, based on response from the DNS resolver library.  This is valid deployment strategy for specific network infrastrucktures with a mixture of IPv4 and IPv6 applications (such as on a campus or an aggregation point of presence).

10 2. Deploying IPv6 over IPv4 Tunnels  Tunneling encapsulates IPv6 traffic within IPv4 packets.  Allowing isolated IPv6 end system and routers to communicate without the need to upgrade the IPv4 Infrastructure that exists between them.  Many topologies possible: Router to Router Host to Router Host to Host  Tunneling is used by most transition mechanisms.

11 IPv6 over IPv4 Tunnels IPv4 Network IPv6 Network IPv6 Network IPv6 header IPv6 data IPv6 header IPv6 data IPv4 header IPv6 header IPv6 data Tunnel: IPv6 in IPv4 Packet Dual-stack Router Dual-stack Router IPv6 host

12 Tunneling Requirements and Security  Endpoint must run in Dual-stack mode.  Possible to protect the IPv6 traffic over IPv4 tunnel by using IPv4 IPSec.  Tunneling use IPv4 protocol 41 to process, if a middle device between the two endpoints of the tunnel filters out this port, the tunnel will not work.

13 IPv6 Tunnel Mechanisms  IPv6 Manually Configured Tunnel  IPv6 over IPv4 GRE Tunnel  Automatic IPv4-Compatible Tunnel  Automatic 6to4 Tunnel  6to4 Relay Router  ISATAP Tunnel  Teredo Tunnel

IPv6 Manually Configured Tunnel  Tunnel endpoints are explicitly configured.  All IPv6 implementations support this.  Provide stable and secure connections for regular communication between two edge routers, or between an end system and an edge router.  Each tunnel is dependently manage, the more tunnel endpoints you have, more tunnels you need.  As with other tunnel mechanisms, NAT is not allowed along the path of the tunnel.

15 Manually Configured Tunnel IPv4 Network IPv6 Network IPv6 Network IPv4: IPv6: 3ffe:b00:c18:1::3 Dual-stack Router Dual-stack Router IPv6 host IPv4: IPv6: 3ffe:b00:c18:1::2

IPv6 over IPv4 GRE Tunnel  Use the standard GRE tunneling technique.  As in manually configured tunnels, these tunnels are links between two points, with a separate tunnel for each link.  Each tunnel is dependently manage, the more tunnel endpoints you have, more tunnels you need.  As with other tunnel mechanisms, NAT is not allowed along the path of the tunnel.

17 IPv6 over GRE Tunnel IPv4 Network IPv6 Network IPv6 Network IPv6 header IPv6 data IPv6 header IPv6 data IPv6 over GRE Tunnel Dual-stack Router Dual-stack Router IPv6 host IPv6 header IPv6 data IPv4 header GRE header

Automatic IPv4-Compatible Tunnel  Uses an IPv4-compatible IPv6 address. IPv4-compatible IPv6 address is the concatenation of zeros in the left-most 96 bits and an IPv4 address embbed in the last 32 bits.  The automatic IPv4-compatible tunnel has mainly been used to establish connection between routers.  Unlike a manually configured tunnel, this tunnel constructs tunnels with remote nodes on the fly.

19 Automatic IPv4-Compatible Tunnel (Cont.)  Manual configuration of the endpoints of the tunnels is not required.  IPv4-compatible tunnel mechanism does not scale well for IPv6 networks deployment, because each host requires and IPv4 address removing the benefit of the large IPv6 addressing space.  The IPv4-Compatible Tunnel is largely replaced by the 6to4.

20 Automatic IPv4-Compatible Tunnel IPv4 Network IPv6 Network IPv6 Network IPv4: IPv6: :: Dual-stack Router Dual-stack Router IPv6 host IPv4: IPv6: ::

Automatic 6to4 Tunnel  The simplest deployment scenario for 6to4 tunnels is to interconnect multiple IPv6 sites, each of which has at least one connection to a shared IPv4 network.  No explicit tunnels.  Each IPv6 domain requires a dual-stack router that automatically builds the IPv4 tunnel using a unique routing prefix 2002::/16 in the IPv6 address with the IPv4 address of the tunnel destination concatenated to the unique routing prefix.  Each site can have only one 6to4 address assigned to the external interface of the router. (recommended)  All sites need to run an IPv6 interior routing protocol for routing IPv6 within the site.

22 Automatic 6to4 Tunnel IPv4 Network IPv6 Network IPv6 Network (=hex :c0a8:6301) 6to4 router 1 6to4 router 2 IPv6 host (=hex :c0a8:1e01) Network prefix: 2002:c0a8:6301::/48 Network prefix: 2002:c0a8:1e01::/48

to4 Relay Routers  The Relay Router: Standard routers but with both a 6to4 IPv6 address and a normal IPv6 address.  Communication between 6to4 sites and native IPv6 domains requires at least one Relay Router.  A global unicast addresses must be used to forward packets to the Internet.

24 6to4 Relay Router IPv4 Network IPv6 Network IPv6 Site Network (=hex :c0a8:6301) 6to4 router 6to4 relay IPv6 host (=hex :c0a8:1e01) Network prefix: 2002:c0a8:6301::/48 Network prefix: 2002:c0a8:1e01::/48 IPv6 Internet

ISATAP Tunnel  Similar to 6to4 tunnels, enable incremental deployment of IPv6 by treating the site IPv4 infrastructure as a nonbroadcast multiaccess (NBMA) link layer.  ISATAP tunnels are available for use over campus networks or for the transition of local sites.  ISATAP uses a 64-bit network prefix from which the ISATAP addresses are formed(0000:5EFE prefixed).

26 ISATAP Tunnel (Cont.)  ISATAP also supports automatic tunneling within site that use nonglobally unique IPv4 address assigement combined with NAT.  However, if a node is part of a private network behind a NAT device that is not participating in 6to4, these tunneling mechanisms cannot be used.

27 ISATAP Tunnel IPv6 Network fe80::5efe:c0a8:0401 3ffe:b00:ffff::5efe:c0a8:0401 ISATAP Router IPv6 host IPv4 Network fe80::5efe:c0a8:0201 3ffe:b00:ffff::5efe:c0a8: fe80::5efe:c0a8:0301 3ffe:b00:ffff::5efe:c0a8:0301

Teredo Tunnel  Provided IPv6 connectivity to nodes located behind one or more IPv4 NATs by tunneling IPv6 packets over the UDP through NAT devices.  The Teredo service is defined for the case where the NAT device cannot be upgraded to offer native IPv6 routing or act as a 6to4 router.  The Teredo network consists of a set of Teredo clients, servers, and relays.

29 3. Deploying IPv6 over Dedicated Data Links  Routers attached to the ISP WANs or MANs can be configured to use the same Layer 2 infrastructure as for IPv4, but to run IPv6.  For example, over separate ATM or Frame Relay PVC or separate optical lambda.

30 4. Deploying IPv6 over MPLS Backbones  IPv6 over MPLS Backbones enables isolated IPv6 domains to communicate with each other over an MPLS IPv4 core network.  A variety of deployment strategies are available or under development, as follows: Deploying IPv6 using tunnels on the customer edge (CE) routers Deploying IPv6 over a circuit transport over MPLS Deploying IPv6 on the provider edge (PE) router (Know as 6PE)

31 5. Protocol Translation Mechanisms  For some organizations or individual might not want to implement any of these IPv6 transition strategies.  A variety of IPv6-to-IPv4 translation mechanisms are under consideration by the IETF NGTrans Working Group, as follows: Network Address Translation-Protocol Translation (NAT-PT) TCP-UDP Relay Bump-in-the-Stack (BIS) Dual Stack Translation Mechanism (DSTM) SOCKS-Based Gateway

32 Protocol Translation Mechanisms  NAT-PT Allows IPv6-only hosts to talk to IPv4 host and Vice-Versa Stateful translation translated at network layer between IPv4 and IPv6 addresses Requires dedicated server Requires at least on IPv4 address  TCP-UDP Relay Similar to NAT-PT, but translated at transport layer Use for native IPv6 networks that want to access IPv4-only hosts, such as IPv4 web servers

33 Protocol Translation Mechanisms  DSTM: Daul-Stack Translation Mechanism Allows IPv6/IPv4 hosts to talk to IPv4 hosts - IPv4 address not initially assigned to dual-stack host Uses a DHCPv6 server to temporary assign IPv4 address; and a special DNS server. Requires at least on IPv4 address per site  BIS: Bump-In-the-Stack Allows IPv4 hosts to talk to IPv6-only host BIS adds new modules to the local IPv4 stack On the BIS host, the IPv6 destination address is mapped into a local private IPv4 address

34 Protocol Translation Mechanisms  SOCK-Based IPv6/IPv4 Gateway Used for communication between IPv4-only and IPv6-only hosts. It consist of additional functionality in both the end system (client) and the dual-stack router(gateway) to permit a communications environment.

35 What is your best Strategy !!

36 Conclusion Technique Suitable For... Comment - Service Provider or Enterprise network that running both IPv4 and IPv6 applications. - Must use IPv6 application in future. - High-Cost. Dual-Stack Backbone - IPv6 network that must connect to other IPv6 network via IPv4 network cloud. - All tunnels use IPv4 Protocol number 41. IPv6 over IPv4 Tunnels Sub- Technique Ma nually Configure Tunnel - Network that want explicit tunnel endpoint. - Not many IPv6 endpoints. - More endpoint, more tunnel, more manage. - NAT is not allowed along the path of the tunnel. - Stable and Sucure

37 Conclusion Over IPv4 GRE Tunnel - similarly to manually configured tunnel. - More endpoint, more tunnel, more manage. - NAT is not allowed along the path of the tunnel. Technique Suitable For... Comment Sub- Technique Auto matic IPv4- Compatible Tunnel - Suitable for IPv6 network that have to create many tunnels to join with other IPv6 networks. - No explicit tunnels. - Must have IPv4 address for create IPv4- compatible IPv6 address. - Easy to create tunnel. - Automatic 6to4 tunnel is better.

38 Conclusion Technique Suitable For... Comment Sub- Technique Auto matic 6to4 Tunnel - Suitable for interconnect multiple IPv6 sites, each of which has at least one connection to a shared IPv4 network. - No explicit tunnels. - Easy to create tunnel. - All sites need to run an IPv6 interior routing protocol. 6to4 Relay Routers - IPv6 network that must connect to 6to4 site and native IPv6 site(IPv6 Internet). - A global unicast address must be used to forward packet to the Internet. ISATAP Tunnel - Similarly to 6to4 tunnel. - Easy to create tunnel. - Careful about node behind NAT device.

39 Conclusion Technique Suitable For... Comment Sub- Technique Teredo Tunnel - IPv6 connect to node that located behind one or more IPv4 NATs. - Tunneling IPv6 packet over UDP through NAT devices. - Require Teredo Servers and Teredo Relays. - Simplify to manage IPv6 connection. - easy to create IPv6 connection. Over Dedicated Data Link - Similarly to deploying over dedicated data link. - Service Provider can create new services. - there are many solution to create services. Over MPLS Backbone

40 Conclusion Technique Suitable For... Comment Sub- Technique - IPv4 or IPv6 that want to join together. But don’t want to implement any of IPv6 translation strategies - There are several IPv6-to-IPv4 translation mechanisms. Prot ocol Translation Tunnel