Mike Hannah is product development manager, Ethernet & Infrastructure, for Rockwell Automation
The first thing you need to know is … don’t panic. The transition from IPv4 to IPv6 will be nothing like the prospect of Y2K in 1998-1999. However, it is a migration issue that you need to keep up to date with, as it will impact the technologies you deploy and how you connect to them on your network.
The second thing you need to know is just what are IPv4 and IPv6:
•Internet Protocol version 4 (IPv4) is the fourth revision in the development of the Internet Protocol (IP) and it is the first version of the protocol to be widely deployed. IPv4 is the 32-bit address used to create the IP addresses used on your computer and network-connected devices in your facility.
•Internet协议版本6（IPv6）是Internet协议的一个版本，旨在成功进行Internet协议版本4（IPv4），当所有可用的IPv4地址用完时。IPv6已经被部署并正在逐渐扩展，因为它提供了大量可用的IP号，据报道，大量的IP数字超过了四分之一的地址。
Getting back to the no need to panic premise, “IPv6 won’t really affect manufacturing networks for years to come,” says Mike Hannah, product development manager, Ethernet & Infrastructure for Rockwell Automation. "Manufacturing networks are still primarily LAN-based architectures, which minimize the number of IP devices that reach out into the public domain."
Rockwell Automation is currently working on developing products that can support IPv4 or IPv6 addressing, but the company is also directing R&D for its network switches toward NAT (network address translation).
“NAT is essentially a way to allow a number of devices that reside on one IP address to be translated into other IP addressing schemes that other manufacturers may have,” says Hannah. “This is a big issue for OEMs. For example, as an end user, when you go to connect two machines on a network, you can’t use the same IP address for both machines. But an OEM doesn’t want to write separate programs for each machine he builds. That’s a maintenance nightmare. That’s where NAT comes in.”
Hannah says Rockwell Automation would, ideally, like to do away with the use of IP addresses for automation equipment. “Why does anyone need to know that?” he asks. “Without checking, you have no idea what your laptop IP address is, but you can still get on the Internet or check your email because you use names of that device (your PC or mobile) on your network.
“That’s where we’re going with devices,” he says. “To give them a logical name on a network rather than an IP address. Because when things do migrate to IPv6, the IP addressing process will only become more complex.”
The NAT naming approach is similar to tagging devices in software applications. Like URL addresses and domain names, you can tag a device as being PLC1, locate it on the network on Machine2 that resides in Plant4 in Brazil. With that kind of tag data, you can go to a Web interface and type in Brazil, Plant 4, Machine 2, PLC1 and see diagnostic data of that device.
汉娜说,使用这种类型的方法,is no need for multiple protocols in a converged network.
In the meantime … before the transition to IPv6 is in full swing or NAT comes into play, Hannah says there’s still much that can be done in the U.S. with IPv4 (China’s out of luck though, as it has already run out of available IPv4 addresses). “There are still millions of devices that can comfortably fit on an IPv4 network because their data never needs to leave the realm of the plant,” he says.
