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Home News IP: networks, access, QoS Getting ready for IPv6
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Getting ready for IPv6

The alarm bells are ringing everywhere: we are are out of IPv4 addresses! What does this mean for the end user? Not much yet! There are enough IPv4 addresses for the backbone infrastructure and servers. The bottleneck is on end user side, especially in some booming regions which have not large enough IPv4 pools available. Already today, Carrier Grade NAT (CG NAT) is used to overcome IPv4 address shortages. In this case, subscribers will a private instead of a public IP assigned. But the shortage is not only based on a growing number of individuals using the internet with a PC. Its also based on the increasing amount of devices used per individual and the probably exploding amount of non-human IP users, e.g. machine-to-machine (m2m) applications.

Is there any need for action for the end user? I would say no. As long as the ISPs can assign IPv4 addresses, everything is fine. Actually the ISPs missed to start the migration to IPv6 early enough. So let's wait until the last v4s are gone.... As soon as ISPs are forced to assign IPv6 addresses, the mess begins.

The problem lies not on the network side. An increasing amount of websites are already reachable on IPv6. Sometimes the IPv6 address is only visible on special domains. E.g. besides the test url http://ipv6.google.com, which has ONLY an IPv6 AAAA record, e.g. needs IPv6 to be reached, most other Google servers have already IPv6 addresses besides their IPv4 addresses. But those are not returned to the average user; name servers return only the IPv4 address. This should avoid problems with incorrect working dual stack clients. There is an agreement between the network operator and Google necessary to return AAAA records. This shows that simply trying to ping6 an arbitrary domain to see who is IPv6 ready, does not give us a correct picture about the IPv6 readiness. The IPv6 readiness on server / information provider side if bigger, but in some cases hidden.

Ideally most servers will be reachable from IPv6 only clients when the end user IPv6 mass roll-out begins. It should be easy for the hosters to get IPv6 ready. We can expect that only a view servers will be IPv4 only when the mass roll-out begins. For those destinations there are special solutions possible, like NAT64.

On the user side the situation is different. Many consumer devices and applications do not support IPv6. What about ADSL routers, WLAN access points, IPTV boxes, IP telephones, VPN clients for home offices, network printers, mobile phones, digital photo frames, etc.? SIP is a challenge as well.
The ISP would probably provide a new ADSL modem/router, but everything on the private LAN is left up to the users. Not all of those devices need Internet connectivity. But for sure there has to be a co-existence of v4 and v6 for some time. And this mix will probably cause a lot of confusion.

Should I get IPv6 now?

There is actually no benefit to get IPv6 now, if you have IPv4. I see only one reason to get IPv6 in parallel to the existing IPv4 connectivity: For point to point protocols like file sharing, and direct peer-to-peer applications like VoIP and video conferencing, it might be a benefit to have IPv6 as well as soon as a critical mass of IPv6 only hosts exists. In the web 2.0 age, and with ever increasing IP connection speeds, more and more information consumers become information providers. And in the near future, those new private providers might be not in the position to get an IPv4 address, unlike the big players. This makes proxies and translation services necessary. It's unclear what limitations this imposes and how reliable this would work.

Besides this, the professional user might want to test today what impact IPv6 has on his home network, how the existing nodes behave and how to protect the network without the usual NAT protection. Some headaches about incoming traffic can certainly be solved with global reachable IPv6 addresses and such scenarios could be tested as well today already.

IPv6 tunnels

A couple of protocols make it possible to establish an IPv6 tunnel over an IPv4 network. The IPv4 network will be used as link layer for a point to point connection to a tunnel service provider and into the parallel world of IPv6 routing.

There are a couple of ISPs offering IPv6 tunnels free of charge. A very popular one is Hurricane Electric. They offer free IPv6 addresses using the 6in4 tunnel protocol. Their offering can be used to get IPv6 on a single host, or by implementing the tunnel endpoint on a router and make IPv6 available on the whole LAN.

Benefits:
- all hosts can use IPv6
- permanent IP addresses
- all hosts are reachable without special NAT traversal measures and can act as servers
- IPv4 remains available

I have set up a configuration with a separate IPv6 tunnel router, primarily for testing. This provides both, IPv4 and IPv6 in my LAN. Especially it is also interesting to test how I can continue to use my IPv4 only devices in a simulated IPv6 only environment, e.g. my Grandstream VoIP desktop phone and apps like Skype.

The steps are described here:

IPv6 using Hurricane Electric's 6in4 tunnel