IPv4 uses a 32-bit address scheme allowing for a total of 2^32 addresses (just over 4 billion addresses). With the growth of the Internet it is expected that the number of unused IPv4 addresses will eventually run out because every device -- including computers, smartphones and game consoles -- that connects to the Internet requires an address.
IPv6
IPv6 has an address space size of 2128 and a standard subnet size of 264
So 2 to the power of 128 ends up being 340,282,366,920,938,000,000,000,000,000,000,000,000 unique IP addresses.
Issues of moving from IPv4 to IPv6
1. Infrastructure Issues:
The TCP/IP suite must be redesigned to support the new address format. e.g. the DNS has defined AAAA resource record for IPv6 (128 bit) but it has defined A resource record for IPv4 (32 bit). The other protocols must be redesigned to support IPv6 including DHCP, OSPF, RIP, BGP, ARP etc.
B. Tunnelling Issues:
Without changing the applications, IPv6 can be implemented in an existing network by using IPv6 over IPv4 tunnelling for connecting the IPv4 nodes to the backbone network. But tunnelling has very less throughput and it needs network managers to configure the tunnel end points information, which is a time consuming process.
C. Financial Issues:
Migrating from IPv4 to IPv6 means, purchasing new network devices (which supports IPv6) such as switches, routers etc. which is a kind of additional investment.
D. Security Issues:
The IPv6 is not used in wide scale till now and it is not tested properly. So no one is very sure about the security level of IPv6.
iDA in helping Singapore to move from IPv4 to IPv6
With the depletion of IPv4 addresses, the Internet community will be moving towards adopting IPv6 technologies. In view of this, IDA sees the need to develop a local pool of IPv6 competent workforce, to support IPv6 adoption.
IDA recently called for a tender to identify a training provider to deliver IPv6 knowledge and skills training to two key target groups - the current workforce of ICT professionals, and the future workforce which comprises students from institutes of higher learning (IHLs) such as the universities, polytechnics and Institutes of Technical Education.
For the current workforce which includes network planners, network administrators and other ICT professionals, the aim is to provide certified IPv6 training courses to ensure that they are equipped with the necessary IPv6 skills to handle IPv6 related tasks such as administration, IPv6 implementation and operational tasks. The courses will cover topics such as IPv6 packet generation and detection, network configuration, IPv6 routing protocols, and steps to migrate to IPv6. Each training programme will include theory, a hands-on component, and an examination.
In addition to this cohort, IDA is also targeting to train ICT professionals to become IPv6-certified trainers who will, in turn, be able to conduct IPv6 courses to train more ICT professionals with IPv6 skills and to develop their own courseware if required.
For the second target group - the students - IDA's main aim is to ensure that they are equipped with IPv6 knowledge prior to joining the IT workforce. This target group will be able to handle IPv6-related tasks and job requirements upon graduation. To deliver this, the training provider will have to develop an IPv6 training programme consisting of IPv6 course modules and an evaluation quiz to be offered to the IHLs.
"We would like to see the training provider establish strong collaborations with the various IHLs and to deliver IPv6 training using various mechanisms, for example, incorporating IPv6 modules into the existing school curriculum, conducting IPv6 workshops or organising industry-sharing sessions on IPv6 implementation experiences," said Mr Eddy Leong, Manager, IPv6 task force at IDA.
Students targeted will be drawn mainly from second and third-year polytechnic students, especially those pursuing diplomas in information technology or network systems, as well as university students doing relevant networking or ICT modules under Electrical and Electronic Engineering and Computer Engineering.
How IPv6 look like?
As previously mentioned, IPv6 addresses are 128 bits long. This number of bits generates very high decimal numbers with up to 39 digits:
2^128-1: 340282366920938463463374607431768211455
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Such numbers are not really addresses that can be memorized. Also the IPv6 address schema is bitwise orientated (just like IPv4, but that's not often recognized). Therefore a better notation of such big numbers is hexadecimal. In hexadecimal, 4 bits (also known as “nibble”) are represented by a digit or character from 0-9 and a-f (10-15). This format reduces the length of the IPv6 address to 32 characters.
2^128-1: 0xffffffffffffffffffffffffffffffff
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This representation is still not very convenient (possible mix-up or loss of single hexadecimal digits), so the designers of IPv6 chose a hexadecimal format with a colon as separator after each block of 16 bits. In addition, the leading "0x" (a signifier for hexadecimal values used in programming languages) is removed:
2^128-1: ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
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A usable address (see address types later) is e.g.:
2001:0db8:0100:f101:0210:a4ff:fee3:9566
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For simplifications, leading zeros of each 16 bit block can be omitted:
2001:0db8:0100:f101:0210:a4ff:fee3:9566 ->
¬ 2001:db8:100:f101:210:a4ff:fee3:9566
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Vangie , B. (2011, January 1). What is the difference between ipv6 and ipv4?. Retrieved from http://www.webopedia.com/DidYouKnow/Internet/ipv6_ipv4_difference.html
How many ip addresses does ipv6 support?. (2008, March 25). Retrieved from http://geekswithblogs.net/devdevin/archive/2008/03/25/120750.aspx
Issues in ipv4 to ipv6 migration. (2011, March). Retrieved from
http://www.caesjournals.org/uploads/IJCAES-CSE-2011-19.pdf
Ida steps up effort to develop ipv6 manpower pool. (2011, August 31). Retrieved from http://www.ida.gov.sg/Infocomm-Landscape/Technology/IPv6/Resources/Latest-IPv6-News/IDA-Steps-Up-Effort-to-Develop-IPv6-Manpower-Pool.aspx
2.3. what do ipv6 addresses look like?. (n.d.). Retrieved from http://tldp.org/HOWTO/Linux IPv6-HOWTO/x422.html
Done by: Tan Ting Hwee (TT01)
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