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IPv6 Transition Mechanism / Tunneling Comparison

Find below a small feature comparison of the various IPv6 transition mechanisms that exist and are in use on the Internet. The various items are color coded to highlight 'positive' and 'negative' things in a protocol. Depending on where one is applying a mechanism and what ones requirements are, these can have advantages or disadvantages.

NameProtocolDynamic endpoint supportedAddress Space usedIPv6 over IPv4IPv4 over IPv6IPv6 over IPv6Packet OverheadMulticastNAT traversalReverse DNS 8Authentication 11Prefix DelegationTraffic AccountingSixXS specific9
Supported by AICCUAvailable on SixXS PoPsCosts credits when down
6in4 (static)proto-41NanyY--MinimumON1ONOOYYY
6in4-heartbeatproto-41Y5anyY--MinimumON1OYOOYYN
6rdproto-41N2anyY--MinimumON1ONOO-Y12-
6to4proto-41N22002::/16Y--MinimumNNON/48NNN-
AYIYAAYIYA (udp)Y5anyYYYHighOYOYOOYYN
GREproto-47NanyYYYMinimumON1OYOONN13-
ISATAPproto-41N2anyY--MinimumNNONNON6N-
L2TPL2TP (udp)Y4anyYYYHighOYOYOOYN13-
TSP/UDPv6UDPv6 (udp)Y4anyYY-MediumOYOYOON7N-
TeredoTeredo (udp)N22001::/323Y--HighNY10NNNN-N-

'Y' = Yes, 'O' = Optional, 'N' = No, 'C' = Configuration only, '-' = Not applicable

1 = Unless the machine performing the NAT function is configured to forward the protocol to the actual endpoint (typically called DMZ mode) or when the NAT supports the protocol by keeping state for outbound packets and relies on that information (which typically fails when multiple senders start using it).
2 = IPv6 prefix will change when IPv4 address changes.
3 = Can be configured to use a different address space.
4 = Requires full renegotation of the tunnel setup.
5 = Heartbeats in the protocol, thus the tunnel moves along directly when the first packet from the new location arrives.
6 = ISATAP is supported natively by most Operating Systems.
7 = Functionality is in development, it is supported by the GoGo6 TSP Client.
8 = Delegation needs to be made from the ISP, for 6to4 one has to request it from NRO 6to4 reverse service.
9 = The SixXS specific columns are not given green/red color as these are not related to featureset of the protocol.
10 = Only non-symmetric NATs
11 = Authentication: N = None; Y = Yes, guest accounts can be used to used to provide anonymous access.
12 = 6rd uses proto-41 as a basis, one needs to configure the manually with the tunnel prefix as a /64 and the IPv4 address of the PoP with prefix length 32.
13 = Ask the staff, if sufficient requests arrive we might support it.

With Teredo and 6to4 there is a likely chance that the IPv6 address will change, especially when the underlying IPv4 address of the tunnel endpoint changes. For all other protocols it depends on the TIC or TSP protocol and the policy on which addresses are given for the tunnels if the addresses remain the same/static.

Other IPv6 transition mechanisms, not listed in the above table:

NameDescription
IVIThe CERNET IVI Translation Design and Deployment for the IPv4/IPv6 Coexistence and Transition
6over4uses IPv4 multicast as a tunneling medium, not used in common deployed scenarios
SIITSimple IP/ICMP Transition
SOCKSSOCKS is a proxy/gateway mechanism, very useful in sitations where SOCKS is already used
NAT-PTNetwork Address Translation-Protocol Transition (deprecated)

Like everything at SixXS, if you have comments/questions/updates/notes, then contact SixXS

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