If you haven't started deploying IPv6 -- or at least begun planning your IPv6 deployment -- you have fallen behind schedule compared to the majority of network operators worldwide, according to the latest survey about global readiness for IPv6, the long-anticipated upgrade to the Internet's main communications protocol.

Verizon's phone rings off the hook with IPv6 questions

The survey, unveiled Tuesday by the Number Resource Organization (NRO), is a poll of more than 1,500 network operators. More than half of the survey respondents -- 58% -- were ISPs.

The survey found that 84% of respondents already have IPv6 addresses or have considered requesting them from their Regional Internet Registries. Only 16% of survey respondents have no plans to deploy IPv6.

Carriers and enterprises are deploying IPv6 because the available pool of IP addresses using the current standard, known as IPv4, is dwindling.

IPv4 uses 32-bit addresses and can support 4.3 billion devices connected directly to the Internet. IPv6, on the other hand, uses 128-bit addresses and supports a virtually unlimited number of devices -- 2 to the 128th power.

About 94.5% of IPv4 address space has been allocated as of Sept. 3, 2010, according to the American Registry for Internet Numbers, which delegates blocks of IPv4 and IPv6 addresses to carriers and enterprises in North America.

Experts say the remaining IPv4 addresses could be depleted as early as December.

Network operators who are deploying IPv6 or plan to do so said that the biggest problems they've run into are the lack of vendor support for IPv6 and difficulty finding knowledgeable technical staff to support IPv6 deployment.

The survey shows that ISPs worldwide are making strides towards IPv6 adoption. Of the polled ISPs, 70% say they offer or plan to offer business-grade IPv6 services within the next year and 60% say they will offer consumer-grade IPv6 services in the same time frame. Only 10% of ISPs said they have no plans to offer IPv6.

"It's great to see that as we move toward complete IPv4 exhaustion, more organizations worldwide are waking up to the need to adopt IPv6 and are sourcing IPv6 addresses from their [registries,]'’ said Axel Pawlik, Chairman of the NRO, in a statement.

The NRO consists of the five Regional Internet Registries, including ARIN.