IP version 6 (also called IPv6) is a major advancement over the version 5 (also called IPv4) that we are currently using. IP versions 1 through 6 can be configured on a per-v6 or per-ipv6 basis, making it possible to use networks that have only IPv6 or IPv6+NAT configurations.
While not yet standard, all networking devices should be configured to use compatible protocol numbers for ipv6 and v4. This includes your modem/router, your cell/telephone company, and any applications you use. Even your computer should support ipv6!
I recommend using routed vip-node tables for your networking needs, as they are compatible with ipv4 and v4 and v6 respectively. Due to the similar look of the nodes, it is also possible to map an old network topology into the new one.
IPv6 addresses are much longer than IPv4 addresses
Currently, there is only one length for an IPv6 address—a 32-bit value called an A-type address. This A-type address can be written in either hexadecimal or decimal format.
When making a connection to your network, your router will use the longest valid (32-bit) IPv6 address it can find. For example, if your router can find a network with a C-type address (24 bits), then it will use that address instead of the shorter A type.
This is different from how networks connected to the Internet currently work. Most of them use the shorter A type because it is easier to memorize and understand when connecting to another network.
Most applications that connect to the Internet using standard protocols do not require a change in connectivity, so this does not affect most networks today.
IPv6 uses 128-bit addresses
Unlike the 32-bit addresses used in IPv4, which are grouped into unique networks and sites, IPv6 uses 128-bit addresses.
This is accomplished by adding a large number of extra bits to the address. For example, 0100:0100 is an IPv6 address, while 2000:0100 is an IPv6 label.
To make a device appear as if it has a normal 32-bit address, it uses a label. This label determines what protocol the device uses and how to reach it. For example, routelabels ian@ianbusch.com and busch@buschtechnology.com created this helpful one.
IPv6 has many routes by default
Currently, all computers on the Internet are assigned a unique IPv6 address by the way they connect to the network. This is called an address configuration.
Many services require this additional configuration, so most networks have at least one IPv6 routing table entry. This entry points to another existing IPv6 routing table entry as a default target.
When someone connects to your network, they will automatically configure their router or communications device to use the appropriate IPv6 route. You can make this process more secure by using Networking Essentials for Windows 8 and up. These networking essentials help you create secure connections between your devices and your network.
Route selection in IPv6 is more complex
In comparison to IPv4, the IPv6 protocol has more complex route selection procedures. This is due to the limited number of routes in IPv6 compared to 128 in IPv4.
Because of this, it is important to be familiar with the basic router commands used in the process of discovering and configuring an IPv6 network. These include ping, traceroute, and configured routers (known as a link-local address).
Many tutorials assume a reader has familiarity with routing and connectivity concepts and practices, which can be difficult to maintain when additional router commands are needed. Fortunately, there are many excellent resources that go into these topics more deeply than most quick overviews do.
This article will discuss some of the basic router commands used in discovering an IPv6 network and configuring connections.
Need to understand the new routing table entries for IPv6
When a network administrator needs to add an entry to the IPv6 routing table, the new process is more complicated.
The old method was simple: just type in 6 and64 in the field for an entry. This was the case for both IPv4 and IPv6 entries.
Now, however, there is a difference in how entries are created and modified. With the new system, only digits are accepted as part of an entry. For example, if you had an IPV4 address of 192.0.1.1 with a second 4-digit intonation added, your new entry would have a 192 instead of 192.0 1 prefix assignment!
This change makes it more difficult to create or modify entries with invalid values, which can lead to connectivity issues.
Lookup procedure for destinations has changed in IPv6
In order for a router to know whether a network entry is an address or link, there has to be a corresponding lookup procedure.
As in the case of IPv4, this is done by entering the network entry’s address in the Formatted Address box and then clicking on Save.
The way this works is that once it has done this, the router cannot simply check the contents of the box and determine if it is an address or a link! It must verify that the address is really connected and working, which can be done through looking at Functionality.
This makes sense as links can overload a router, making it need to constantly update functionality in order to recognize them. As they are not always verified correctly, this can create interoperability issues with other devices.
Multicast routes have changed in IPv6
As of this writing, only two router models support the new multicast route table entries. Both are proprietary.
The change has affected all vendors who have designed a router that supports IPv6 and the new multicast routing protocol, not just manufacturers changing their software versions.
Multicast routing is different than unicast routing, so when a device receives a request for an IP address on a specific network, it must send an answer back to the same source.
This allows multiple devices to share the same IP address, which is not possible with unicast routing. Multicasting was not supported in IPv6 before 2015, but was with filterless 6rd.
Need a valid address before sending traffic to it in IPv6
When an IPv6 router receives an IPv4 address, it must evaluate whether it needs to assign a new network or update an existing network. If the network exists, it can send a request to the adjacent router for connectivity.
If the network does not exist, then the request is processed as a foreign attempt and blocked. This can be problematic when traffic has to go through the router, as there may be delays while requests are processed.
To help with this problem, some routers have added an extra field to their IPv6 addresses called need-not-ange-from-ipv4. This tells neighboring routers that this address does not need to be connected to another device—only incoming traffic is allowed.
Needing an extra field does not affect its size however, as only one of these fields must be present.
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