IPv6 static vs dynamic unicast addressing

"IPv6 Static Vs Dynamic Unicast Addressing with a Recommendation for a medium sized company"


This report will talk about both IPv4 (Internet Protocol version 4) and IPv6 (Internet Protocol version 6) on how IPv4 uses the 32bit addressing system and why IPv6 uses 128bit addressing system. The report will go in to comparison of static IPv6 unicast addressing to the various ways in which unicast addressing can be dynamically assigned to a IPv6 host while also giving advantages and disadvantages to each approach, with stating the advantages and disadvantages to the approaches this report will also detail what services, infrastructure or configuration will be required in each case. The report will also include a recommendation into using the cases stated before on implementing these approaches on a medium sized organisation with around approximately 1000 hosts and several dozen networks.

This report will contain diagrams to help aid the area of topic which is being described also there will be quotations from other authors to help back up any information stated in report references to theses quotations will be at the end under the headed section called references, I myself will also be giving my own thoughts and opinions on what has been said on this report in the conclusion section where I will sum up what I have talked about and give my own input I will also be making a recommendation in to a particular approach for using the cases stated above for a medium sized organisation.

IPv4 (Internet Protocol Version 4)

Internet Protocol version 4 or IPv4 as it is referred to is an addressing system that uses 32bit or 4 bytes theses are broken up in to 4 octets which are split up into classes that range from A to E. The octets are split into two sections one is called the network section and the other is the host section depending on what class of IP address system you will require the network section might only occupy one octet leaving the other thee octet available to make networks and hosts. Class A addresses require the first octet for network purposes, for example if the IP address is the first octet will be reserved for network and the remaining three octets will be for host use, Class A will make 126 networks available for use with 16,777,216 available addresses per network class A IPv4 Addresses are mostly used for private addresses which addresses range from 0 to 127.

Below is a diagram to help describe what has been said above about IPv4 classes also not noted on the diagram is that there is a loopback address for each class which will be the last available address on each class.

IPv6 (Internet Protocol Version 6)

Internet Protocol version 6 or IPv6 as it will be referred to in the remainder of this report is designed to be the next generation in IP addressing it was developed to replace IPv4 as the addressing system for IPv4 will eventually be exhausted as the available addresses will all be used up. The reason why IPv6 has been chosen to be an ideal replacement for IPv4 as it uses a 128bit addressing system which will allow for 2218 (3.4x1038) addresses available for use which is "79 Octillion times the IPv4 address space"(Network Dictionary,2010) because IPv6 uses a 128bit addressing system it is a larger address than the address used in the IPv4 which uses 4 octet but like IPv4 IPv6 is divided up in to two sections called Prefix and Interface ID, the Prefix section of the address is used to identify a subnet for that address. The Interface ID section of the address is used to identify an interface for that particular address which will need to be unique to that subnet.

To help describe what an IPv6 address looks like there has been a diagram included below which shows a broken down picture of the network prefix and interface ID. Here is an example of an IPv6 address: 2001:0:5ef5:73ba:2cba:1576:a314:3db

Static IPv6 addressing Vs Dynamic IPv6 Addressing

With the introduction of IPv6 there has been a lot of talk about the advantages and disadvantages that it will bring in this section on the report it will discuss the advantages and disadvantages of Static and Dynamic Unicast Addressing in IPv6.

Static IPv6 Addressing

IP addresses in IPv6 can be set up in the same way in which they have been set up in IPv4 they can either be static or dynamic. Static IP addressing is the means in which having an address is setup so that a soon as the PC is switched on it has an IP address and that it can communicate with other machines on the network but a dynamic IP address is different from static IP addressing as the host does not have an IP Address they will need to achieve an IP address through the DHCP before they can have access to the network.

In IPv6 Static IP addresses can be assigned by the network administrator or you can assign an IPv6 address yourself there are a few things that would need to be taken in to consideration before statically assigning a IPv6 address like IPv4 for an example if the address for IPv4 address was this could not be allowed to be entered in to and IPv6 address as it has not been translated in IPv6 format were it would need to be changed to 8 part Hexadecimal address stating the correct subnet Prefix and interface ID that would correspond to the Prefix.

Advantages of Static IPv6 Addressing

One of the main reasons that IPv6 has been tipped to be the successor of IPv4 is that not only does it expand is address range to be greater than IPv4 but it also "offers superior security features"(IPv6.com,2010) that would positive for static IP addressing as in IPv4 the security was not adequate and was vulnerable to attack through static IP addresses as unauthorised users could scan the network to find the IP address of that particular host as "viruses and worms can use compromised hosts to infect remote systems. IPv4's small address space can facilitate malicious code distribution"(Samuel Sotillo, 2006).

One of the ways in which IPv6 security is step better than IPv4 is that it uses IPsec, IPsec is a protocol which is used to protect the Internet Protocol (IP) by authentication and encrypting data that is set from host to host. It will also give the network administrator more control over the network as he/she will know which IP addresses will be used.

Disadvantages of Static IPv6 Addressing

There are a few disadvantages to static IP addressing in IPv6 one is that is that it will take time for the administrator to assign each host a static IPv6 address this is depending on the size of the organisation.

Dynamic IPv6 Addressing

As said before that setting up dynamic addressing there would need to be DHCP to enable a host to achieve an address that would be perfectly acceptable in for a host to acquire an IPv4 address but with IPv6 it is different there is no need for a DHCP because IPv6 address use stateless auto configuration which is a feature that IPv6 host can make up their own addresses, A full IPv6 address is made up of 128bits the host has 64bits which is a combination of the MAC address and the Prefixes that are provided by the ISP (Internet Service Provider) to create one half of the 128bit address to achieve the complete address the router sends out "router advertisements" (RAs)( Iljitsch van Beijnum, 2007) which will contain the information on the other half of the addresses leaving the host to make up its address.

For an example if the hosts MAC addresses is 00:0a:85:f1:29:9e this would result in the first 64bit of the addresses to look like this 20a:85ff:fef1:299e this is combination the MAC address and the prefix supplied by the ISP. The router will send out the "advertisements that contains the addresses of recursive DNS servers" (J. Jeong, 2007) which will allow host to keep track of the addresses of DNS servers, once the host has the router advertisements they are then able to complete the other 64bits to the have a complete 128bit IPv6 address. One configuration which needs to be considered is that the router has to be configured so that it may send out these router advertisements.

Advantages of Dynamic IPv6

Advantages of dynamic IPv6 addresses would be that as mentioned above that because the host combined with router advertisements are able to create their own 128bit addresses which would mean that there is no need to spend time setting up a DHCP as the addresses are stateless although there are DHCPv6 which can be configured to that administrators may have more control over the addresses that are assigned theses are known as stateful addresses.

Disadvantages of Dynamic IPv6

A downfall to dynamic IPv6 addressing is that although there will be no need to set up a DHCP the network administrator would not have control over who has what IP address thus meaning that if an unauthrorised user was to gain access to the network they would be able to obtain an address through auto configuration through router advertisments


Along with stating the advantages and disadvantages of both static IPv6 unicast addressing there has been included a recommendation of one of the approaches to be implemented within a medium sized company with 1000 hosts and several networks.

If the above approaches are to be taken into consideration into implement IPv6 addresses within the business the first thing to look at is what would the business benefit more from having looked over the above approaches if the company is to adopt static IPv6 methods then it would take time for the addresses to be put in place by the network administrator but advantage to this approach means that the administrator would have more control over the network mostly used if a company has lots of servers.

If the company was to adopt a dynamic approach to IPv6 there would not be no need for the network administrator to assigned each host an IP address meaning that everyone will be assigned an dynamic IP address through router advertisements the downside to this would mean that the administrator would not have control over who uses what IP address.

The recommendation I would put forward would be a mixture of both static and dynamic IPv6 addresses to be implemented. Personally I would have static IP addresses setup for servers that users will be able to connect to use their services as the addresses for the servers need to be constant as the network administrator will need to know the addresses of the servers to have control over them.

The recommendation for using dynamic IPv6 addresses within the company would be for the fact that for different networks there be a DHCPv6 server setup so that the network administrator can set the ranges of IP addresses on that network where as if the stateless auto configuration is to be taken then any user can gain access to the network as all they need is a MAC address and have the router advertisements to gain an address.


In this report I have discussed both static and dynamic IPv6 addressing while stating the advantages and disadvantages of each approach, other areas which I have touched on while talking about the advantages and disadvantages are the services and configuration, I have also included a recommendation for company of 1000 host and several networks taking into the consideration of the above approaches. Having done research into IPv6 I would definitely agree that IPv6 is the successor to IPv4 as the address space it creates is more than enough to satisfy every user on earth as with the current growth in technology with mobile phones becoming internet devices requiring IP addresses there must be about a billion mobile phones on the earth and with the current host with IP addresses there is no way IPv4 would be able to host the address space. The security with IPv6 is another improvement on IPv4 as IPv6 makes IPsec mandatory when sending packets although IPsec was available for IPv4 it was optional.


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Iljitsch van Beijnum, 2007, Article, Everything you need to know about IPv6, URL: http://arstechnica.com/hardware/news/2007/03/IPv6.ars/2 Last Accessed: 25/03/10

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J. Jeong, 2007, Experimental Memorandum, IPv6 Router Advertisement Option for DNS Configuration, URL: http://www.ietf.org/rfc/rfc5006.txt Last Accessed: 26/03/10

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Samuel Sotillo, IPv6 Security Issues, 2006, Website, URL: http://www.infosecwriters.com/text_resources/pdf/IPv6_SSotillo.pdf

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