Download Introduction to IPv6

Transitioning to IPv6:
Issues and Mechanisms
Jeff Doyle
Senior Network Architect
5/25/2017
Copyright © 2006 Juniper Networks
APRICOT 2006
Perth, Australia
1 March, 2006
1
3 Types of Transition Mechanisms

Dual Stacks


Tunnels




IPv4/IPv6 coexistence on one device
For tunneling IPv6 across IPv4 clouds
Later, for tunneling IPv4 across IPv6 clouds
IPv6 <-> IPv6 and IPv4 <-> IPv4
Translators

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IPv6 <-> IPv4
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2
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
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3
Dual Stacking
IPv4-only Host:
Dual-Stacked
Host:
stan.v4.com
207.14.182.10
Query:
stan.v4.com?
A Resource Record:
207.14.182.10
199.15.23.87
3ffe:3700:1100:1:210:a4ff:fea0:bc97
DNS
IPv6-only Host:
ollie.v6.com
3ffe.2301.1700.1.abcd.1234.dada.1
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Dual Stacking
IPv4-only Host:
Dual-Stacked
Host:
stan.v4.com
207.14.182.10
Query:
ollie.v6.com?
AAAA Resource Record:
3ffe.2301.1700.1.abcd.1234.dada.1
199.15.23.87
3ffe:3700:1100:1:210:a4ff:fea0:bc97
DNS
IPv6-only Host:
ollie.v6.com
3ffe.2301.1700.1.abcd.1234.dada.1
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5
Tunnels


Necessary if all nodes between communicating
endpoints are not dual stacked
Add a layer of complexity to the network and the
transition plan
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6
Tunnel Applications
IPv4
IPv6
IPv6
IPv6
Router to Router
IPv4
IPv6
Host to Host
IPv4
IPv6
IPv6
Host to Router / Router to Host
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7
Tunnel Types
Automatic Tunnels
 Application:
Configured Tunnels
 Application:

Permanent site-to-site
connectivity
 Carriers, SPs, large
backbones




Technologies:

GRE, IP-IP, IPSec…
 MPLS




Technologies:


Controlled, deterministic





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Transient connectivity
Connectivity across “v6 unaware”
segments
Router to Router
Host to Router
Host to Host
Tunnel Brokers
6to4
ISATAP
Teredo?
DSTM
Possibly non-deterministic
Possible security risks
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8
Automatic Tunnels:
Endpoint Determination
 Configured tunnels: Endpoints (IP addresses) are
determined by administrator
 Automatic tunnels require an automatic endpoint
determination
 Two Approaches:
1. Assign them from an authoritative server
 Tunnel brokers, Teredo, DSTM
2. Imbed them in IPv6 addresses
 6to4, ISATAP
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Authoritative Server Approach:
Tunnel Broker
3
Tunnel
Broker
1
2
6
Client
IPv4
Network
4
DNS
AAA Authorization
2.
Configuration request
3.
TB chooses:
•
TS
•
IPv6 addresses
•
Tunnel lifetime
4.
5.
TB registers tunnel IPv6 addresses
Config info sent to TS
6.
Config info sent to client:
•
Tunnel parameters
•
DNS name
Tunnel enabled
7.
5
7
IPv6 Tunnel
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1.
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Tunnel
Server
IPv6
Network
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Imbedded Endpoint Address
Approach: 6to4
138.14.85.210 (Dotted Decimal) = 8a0e:55d2 (Hex)
IPv4 Interface: 138.14.85.210
IPv4 Address: 65.114.168.91
6to4 prefix: 2002:8a0e:55d2::/48
6to4 prefix: 2002:4172:a85b::/48
IPv4
Network
IPv6
Site
IPv6
Site
6to4 Router
6to4 Router
6to4 address:
6to4 address:
2002:8a0e:55d2:1:230:65ff:fe2c:9a6
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2002:4172:a85b:1:20a:95ff:fe8b:3cba
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Imbedded Endpoint Address
Approach: 6to4
6to4 Router Recognizes
6to4 Prefixes
Local Tunnel Endpoint =
138.14.85.210
Remote Tunnel Endpoint =
65.114.168.91
Packet Source Address:
2002:8a0e:55d2:1:230:65ff:fe2c:9a6
Packet Destination Address:
2002:4172:a85b:1:20a:95ff:fe8b:3cba
IPv4
Network
IPv6
Site
IPv6
Site
IPv6
6to4 Router
6to4 Router
Host1:
2002:8a0e:55d2:1:230:65ff:fe2c:9a6
Host2:
2002:4172:a85b:1:20a:95ff:fe8b:3cba
DNS:
Host2 = 2002.4172.a85b:20a:95ff:fe8b:3cba
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12
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
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13
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)

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Translator Types

Network level translators
 Stateless IP/ICMP Translation Algorithm (SIIT)(RFC 2765)
 NAT-PT (RFC 2766)


Transport level translators


Bump in the Stack (BIS) (RFC 2767)
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
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15
Stateless IP/ICMP Translation (SIIT)
204.127.202.4
IPv4
Network
IPv6
Network
Source = 216.148.227.68
Dest = 204.127.202.4
SIIT
Source = 204.127.202.4
Dest = 216.148.227.68
Source = ::ffff:0:216.148.227.68
Dest = ::ffff:204.127.202.4
Source = ::ffff:204.127.202.4
Dest = ::ffff:0:216.148.227.68
SIIT also changes:
•Traffic Class   TOS
•Payload length
•Protocol Number   NH Number
•TTL   Hop Limit
3ffe:3700:1100:1:210:a4ff:fea0:bc97
216.148.227.68
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Copyright © 2006 Juniper Networks
16
Network Address Translation - Protocol
Translation (NAT-PT)
IPv4 Pool: 120.130.26/24
IPv6 prefix: 3ffe:3700:1100:2/64
IPv6
Network
IPv4
Network
DNS
v4host.4net.org?
NAT-PT
v4host.4net.org
A 204.127.202.4
v4host.4net.org
AAAA 3ffe:3700:1100:2::204.127.202.4
v4host.4net.org
204.127.202.4
v6host.6net.com
3ffe:3700:1100:1:210:a4ff:fea0:bc97
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Network Address Translation - Protocol
Translation (NAT-PT)
IPv6
Network
IPv4 Pool: 120.130.26/24
IPv6 prefix: 3ffe:3700:1100:2/64
IPv4
Network
Mapping Table
Inside
3ffe:3700:1100:1:210:a4ff:fea0:bc97
DNS
Outside
120.130.26.10
Source = 3ffe:3700:1100:1:210:a4ff:fea0:bc97
Dest = 3ffe:3700:1100:2::204.127.202.4
NAT-PT
Source = 120.130.26.10
Dest = 204.127.202.4
Source = 204.127.202.4
Dest = 120.130.26.10
v4host.4net.org
204.127.202.4
Source = 3ffe:3700:1100:2::204.127.202.4
Dest = 3ffe:3700:1100:1:210:a4ff:fea0:bc97
v6host.6net.com
3ffe:3700:1100:1:210:a4ff:fea0:bc97
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18
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
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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

Access
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Access
IPv4/IPv6
IPv4
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Transition Strategies:
Separate IPv4/IPv6 Backbones
(Possibly) higher capital expense
 Lower operational complexity
 Low risk to operational network
 Easier, more incremental migration

IPv6
Access
Access
IPv4
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21
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.


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i.e., human resource expenses
Not capital expenses
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Thank you!
[email protected]
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