1. Copyright © 2006 Juniper Networks
Transitioning to IPv6:
Issues and Mechanisms
Jeff Doyle
Senior Network Architect
APRICOT 2006
Perth, Australia
1 March, 2006
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

2. 3 Types of Transition Mechanisms
Dual Stacks
IPv4/IPv6 coexistence on one device
Tunnels
For tunneling IPv6 across IPv4 clouds
Later, for tunneling IPv4 across IPv6 clouds
IPv6 <-> IPv6 and IPv4 <-> IPv4
Translators
IPv6 <-> IPv4
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

3. Copyright © 2006 Juniper Networks
Dual Stacking
In most cases, the simplest approach
IPv6 now supported on most modern network platforms
Routers
Servers
Hosts
If (almost) everything is “bilingual”, transition is controlled by DNS
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

4. Copyright © 2006 Juniper Networks
Dual Stacking
IPv4-only Host:
Dual-Stacked
Host:
stan.v4.com
Query:
stan.v4.com?
A Resource Record:
DNS
IPv6-only Host:
3ffe:3700:1100:1:210:a4ff:fea0:bc97
ollie.v6.com
3ffe abcd.1234.dada.1
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

5. Copyright © 2006 Juniper Networks
Dual Stacking
IPv4-only Host:
Dual-Stacked
Host:
stan.v4.com
Query:
ollie.v6.com?
AAAA Resource Record:
3ffe abcd.1234.dada.1
DNS
IPv6-only Host:
3ffe:3700:1100:1:210:a4ff:fea0:bc97
ollie.v6.com
3ffe abcd.1234.dada.1
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

6. Copyright © 2006 Juniper Networks
Tunnels
Necessary if all nodes between communicating endpoints are not dual stacked
Add a layer of complexity to the network and the transition plan
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

7. Host to Router / Router to Host
Tunnel Applications
IPv4
Router to Router
IPv6
IPv4
Host to Host
IPv6
IPv6
Host to Router / Router to Host
IPv4
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

8. Copyright © 2006 Juniper Networks
Tunnel Types
Configured Tunnels
Application:
Permanent site-to-site connectivity
Carriers, SPs, large backbones
Technologies:
GRE, IP-IP, IPSec…
MPLS
Controlled, deterministic
Automatic Tunnels
Application:
Transient connectivity
Connectivity across “v6 unaware” segments
Router to Router
Host to Router
Host to Host
Technologies:
Tunnel Brokers
6to4
ISATAP
Teredo?
DSTM
Possibly non-deterministic
Possible security risks
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

9. Automatic Tunnels: Endpoint Determination
Configured tunnels: Endpoints (IP addresses) are determined by administrator
Automatic tunnels require an automatic endpoint determination
Two Approaches:
Assign them from an authoritative server
Tunnel brokers, Teredo, DSTM
Imbed them in IPv6 addresses
6to4, ISATAP
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

10. Authoritative Server Approach: Tunnel Broker
AAA Authorization
Configuration request
TB chooses: TS
IPv6 addresses
Tunnel lifetime
TB registers tunnel IPv6 addresses
Config info sent to TS
IPv6 Tunnel
Config info sent to client:
Tunnel parameters
DNS name 3 4
Tunnel
Broker
DNS
Tunnel enabled 1 2 5 6
IPv4 Network
Client
Tunnel
Server
IPv6 Network 7
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

11. Imbedded Endpoint Address Approach: 6to4
(Dotted Decimal) = 8a0e:55d2 (Hex)
IPv4 Interface:
IPv4 Address:
6to4 prefix: 2002:8a0e:55d2::/48
6to4 prefix: 2002:4172:a85b::/48
IPv4
Network
IPv6 Site
IPv6 Site
6to4 Router
6to4 Router
6to4 address:
2002:4172:a85b:1:20a:95ff:fe8b:3cba
6to4 address:
2002:8a0e:55d2:1:230:65ff:fe2c:9a6
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

12. Imbedded Endpoint Address Approach: 6to4
6to4 Router Recognizes
6to4 Prefixes
Local Tunnel Endpoint =
Packet Source Address:
2002:8a0e:55d2:1:230:65ff:fe2c:9a6
Packet Destination Address:
2002:4172:a85b:1:20a:95ff:fe8b:3cba
Remote Tunnel Endpoint =
IPv6
IPv4
Network
IPv6 Site
IPv6 Site
6to4 Router
6to4 Router
Host1:
2002:8a0e:55d2:1:230:65ff:fe2c:9a6
DNS:
Host2 = a85b:20a:95ff:fe8b:3cba
Host2:
2002:4172:a85b:1:20a:95ff:fe8b:3cba
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

13. Copyright © 2006 Juniper Networks
Translators
Necessary if IPv6-only endnode and IPv4-only endnode must speak
Very few situations where translators should be required
Dual stacking and/or tunneling should be sufficient in most cases
The great majority of modern IPv6-capable network/host systems are dual stack, not IPv6-only
IPv6-only devices are likely to be specialized, and in IPv6-only networks
Add another layer of complexity to the network and the transition plan
Avoid them if you can
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

14. Copyright © 2006 Juniper Networks
Translator Types
Network level translators
Stateless IP/ICMP Translation Algorithm (SIIT)(RFC 2765)
NAT-PT (RFC 2766)
Bump in the Stack (BIS) (RFC 2767)
Transport level translators
Transport Relay Translator (TRT) (RFC 3142)
Application level translators
Bump in the API (BIA)(RFC 3338)
SOCKS64 (RFC 3089)
Application Level Gateways (ALG)
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

15. Copyright © 2006 Juniper Networks
Translator Types
Network level translators
Stateless IP/ICMP Translation Algorithm (SIIT)(RFC 2765)
NAT-PT (RFC 2766)
Bump in the Stack (BIS) (RFC 2767)
Transport level translators
Transport Relay Translator (TRT) (RFC 3142)
Application level translators
Bump in the API (BIA)(RFC 3338)
SOCKS64 (RFC 3089)
Application Level Gateways (ALG)
NAT-PT (using SIIT procedures) has
emerged as the dominant translator
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

16. Stateless IP/ICMP Translation (SIIT)
IPv4 Network
Source =
Dest =
IPv6 Network
SIIT
Source =
Dest =
Source = ::ffff:0:
Dest = ::ffff:
Source = ::ffff:
Dest = ::ffff:0:
SIIT also changes:
Traffic Class   TOS
Payload length
Protocol Number   NH Number
TTL   Hop Limit
3ffe:3700:1100:1:210:a4ff:fea0:bc97
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

17. Network Address Translation - Protocol Translation (NAT-PT)
IPv6 Network
IPv4 Network
IPv4 Pool: /24
IPv6 prefix: 3ffe:3700:1100:2/64
DNS
v4host.4net.org A
v4host.4net.org?
NAT-PT
v4host.4net.org
AAAA 3ffe:3700:1100:2::
v4host.4net.org
v6host.6net.com
3ffe:3700:1100:1:210:a4ff:fea0:bc97
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

18. Network Address Translation - Protocol Translation (NAT-PT)
IPv6 Network
IPv4 Network
IPv4 Pool: /24
IPv6 prefix: 3ffe:3700:1100:2/64
Mapping Table
Inside Outside
3ffe:3700:1100:1:210:a4ff:fea0:bc
DNS
Source =
Dest =
Source = 3ffe:3700:1100:1:210:a4ff:fea0:bc97
Dest = 3ffe:3700:1100:2::
NAT-PT
Source =
Dest =
v4host.4net.org
Source = 3ffe:3700:1100:2::
Dest = 3ffe:3700:1100:1:210:a4ff:fea0:bc97
v6host.6net.com
3ffe:3700:1100:1:210:a4ff:fea0:bc97
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

19. Copyright © 2006 Juniper Networks
Problems with NAT-PT
Statefulness (mapping table) restricts asymmetric traffic
Complicates network troubleshooting
Single point of failure or attack
Possible DNS difficulties
Many of the same constraints, vulnerabilities as v4 NAT
Nevertheless, some see v6 NAT as a necessity
Maintaining provider independence, for example
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

20. Transition Strategies: Dual Stacked IPv4/IPv6 Backbone
(Possibly) lower capital expense
(Possibly) higher operational complexity
More risk of network disruption during migration
Less incremental migration
Legacy equipment issues
IPv4
IPv4/IPv6
Access
Access
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

21. Transition Strategies: Separate IPv4/IPv6 Backbones
(Possibly) higher capital expense
Lower operational complexity
Low risk to operational network
Easier, more incremental migration
IPv6
IPv4
Access
Access
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

22. Copyright © 2006 Juniper Networks
Conclusions
Dual stacking is the simplest approach
Tunnel only when necessary
Translation should seldom be needed, if at all
A long-range transition plan reduces cost
IPv6 SW/HW phased in as part of normal network evolution
Biggest transition expense is likely to be planning, testing, inventory, training, etc.
i.e., human resource expenses
Not capital expenses
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.

23. Copyright © 2006 Juniper Networks
Thank you!
11/12/2018
Copyright © 2006 Juniper Networks
Author: G. Arheilger, Juniper Networks, EMEA Central
Copyright © 2003 Juniper Networks, Inc. All rights reserved.