IP version six link local addresses are unicast addresses but restricted to the local link, hence the
name link local.
They are still 128 bits in length.
The interface identifies automatically configured with the UI address.
Note, however, that the most significant ten bits of the address start with F 80 in hexadecimal or
seven binary ones followed by binary zero followed by binary one followed by binary zero in binary.
Routing protocols, use link local addresses to advertise routes to one another.
And in IP version six, a node having a global unicast address on a local link will use the link local
address of its default IPV six router rather than the global unicast address.
This is good because if the network is renumbered, the default router can still be used using the link
local address.
Linked local addresses won't change when you remember your global unicast addresses.
Site local addresses.
Also another type of unicast address but have a limited scope to a site site.
Local addresses are not enabled by default on nodes, unlike linked local addresses, which are automatically
enabled.
In other words, you have to configure site local addresses.
The address starts with FEC zero, with the most significant ten bits set in binary to seven binary
ones followed by binary zero followed by two binary ones.
So the most significant ten bits of a psychological address always starts with this value site.
Local addresses are the IP version six equivalent of RFC 1918 addresses.
These, however, have been deprecated and should no longer be used.
But the idea was that you could have many, many subnets within your organisation as you would now have
54 bits for submitting.
Which is far greater than the 16 bits that you get with global unicast addresses.
The next type of address is an IPv4 compatible IPv6 address.
In this address, the most significant 96 bits are set to zero, and the least significant 32 bits are
set to the IP version for address.
This is a special, unique cost IPv6 address used as a transmission mechanism on hosts and routers to
automatically create IPV four tunnels to deliver IPV six packets over IPV four networks.
This mechanism allows for the automatic establishment of an IPV six over IPV four tunnel between two
nodes over an IPv4 infrastructure using the IP version for destination address inside the destination
IPV six address.
So the format of the address would be as follows The most significant 96 bits would be set to zero.
The least significant 32 bits would be set to the decimal representation of the IP version for address
that could be rewritten as follows.
So colon.
Colon 19202 100.
The decimal IP version for address could also be written as a hexadecimal value.
So this would be the same address.
For example, 192 in decimal is equal to c zero in hexadecimal.
Notice one two equates to C zero.
So once again, it's used to represent the addresses of IP version four nodes as IP version six addresses.
But please note that this address format has been deprecated in favor of other more enhanced transition
mechanisms such as dynamic net P RT or net protocol translation.
It's also important to point out that the IPv4 compatible IPv6 addresses use a slash 96 mask, so 96
bits are set to zero.
The mask is slash 96.
The least significant 32 bits are set to the IP version for address, either in dotted decimal notation
such as here or a hexadecimal representation of the address like in this example.
As I've already mentioned, unspecified addresses is where the address is set to zeros, and it's used
as a placeholder where no address is available.
So during an initial DHCP request or duplicate address detection.
Loopback addresses are set to zeros.
And lastly, a one.
This is equivalent to 120 7001 an IP version four and is used by the host to identify itself.
I've already demonstrated this.
And can be used to check that the IPv6 protocol stack is functioning properly.
So in summary, IPV six unicast addresses can be broken up into six types.
The first type is unspecified.
So colon, colon slash 128, then loopback colon colon one, slash 128.
And then we have aggregated all global unicast addresses and yes, some examples of ranges.
These, remember, are globally unique.
There is no need for net.
Because you have global reach ability.
That address is unique globally.
Then we have linked local addresses, which are addresses used only on the local link, used for example
by routing protocols.
Starts with F 80.
In hexadecimal.
Site local addresses are similar in concept to RFC 1918 private addresses.
They start with fec0.
IPV four compatible addresses the most significant 96 bits.
Ossett set to zero.
And this allowed us to create automatic tunneling of IPV six over IPV four.
Both site local and IPV four compatible addresses have been deprecated.
Now multicast addresses are broken up into two parts f008.
I signed multicast addresses and then you have solicited node multicast addresses for each unicast and
any cost address configured on an interface of a node or router.
A corresponding solicited node multicast addresses automatically enabled the solicited node.
Multicast address is scoped to the local link.
This is an example is used for the replacement of OP in IP version for if you remember, OP uses broadcasts,
but broadcasts are no longer supported in IP version six.
So the solicited node multicast address is used by nodes and routers to learn the link layer addresses
of neighbor nodes and routers on the same link.
So very similar in concept to OP, but we are not using broad costs, we're using multi costs.
Duplicate address detection or D&D can be used by a node to verify whether an IPV six address is already
in use on its local link before using that address to configure its own IPV six address with stateless
order configuration.
Stateless order configuration is a new function enabled by IP version six.
By having a much larger dress space.
IP Version six is designed to enable order configuration of IP addresses on devices while keeping those
addresses unique.
This enables basic serverless configuration of nodes as well as easy re numbering routers.
Send periodic router advertisements using a link local address.
I wouldn't try and remember these addresses, but the address used would be this, but the source address
used would be this.
Going to a multicast address of f02.
Colon colon one.
In other words, all nodes on the link the routing uses ICMP version six Type 134, which is known as
a right advertisement, telling nodes information like what prefix to use.
What the default gateway is and the lifetime of this prefix that's advertised to them.
The advertisement period can vary.
And you can also change the lifetime of the prefix advertised to hosts.
When our host initially boots up the node will need its IP address as soon as possible and normally
in the early stages of the boot process, it could wait for a long period of time for the next router
advertisement to get the information it needs to configure its interfaces.
And thus a node will send a write a solicitation message to routers on the network, asking them to
reply immediately with a router advertisement so that the node can immediately order configure its IP
address.
So the host will send a writer solicitation to all writers using the all writers multicast address f
zero to colon colon to the host users.
ICMP Version six Type 133.
Again, I wouldn't try and remember all of these ICMP types.
Just understand the process.
The host uses its link local address as the source of the solicitation request.
So it uses F 80, followed by its UI address as the source.
And the message goes to destination of F zero to colon.
Colon to all routers on the local link.
Arata will reply to that message.
Using ICMP version six Type 134.
The writer will use its link local address of F 80 and UI as the source, and the destination will go
to f02 colon column one.
In other words, all nodes on the link.
So order configuration has the advantage in that it enables plug and play configuration of IPV six devices.
You just configure an IP address on the router and by default, router advertisements are enabled.
PCs and other devices can be plugged into the network and they will automatically learn the prefix assigned
to them and default gateway.
Without the administrator configuring a DHCP server or manually configuring IP addresses, hosts are
automatically configured with the prefix received and then they combine that with their link layer address.
In other words, the UI address to configure a local IPV six address to allow them to communicate with
the network.
Another advantage of stateless auto configuration is the re numbering of devices erotic and just advertise
a new prefix and time out the old prefix if required, and hosts will automatically be updated with
the new prefix information.
So gone are the days of struggling to reconfigure and remember the IP addresses of hosts.
Now stateful DHCP still exists in version six of DHCP.
It provides more control than stateless auto configuration.
For example, if using Cisco IP phones, they need to learn an option 150 from a DHCP server which tells
the phone's the TFTP server they need to connect to you to download their configuration as well as their
firmware.
So DHCP in some cases is still required as it gives us more control and more options.
Now that said, you can use stateful DHCP concurrently with stateless order configuration so you don't
have to make an explicit choice between the two.
Stateful.
The app can also provide IP version six addresses and the absence of routers.
So in this topology there are no routers, so DHCP server can be configured.
It can also be used for network remembering in the same way as in IP version four and it can be used
for automatic domain name registration of hosts using dynamic DNS.
So a lot of the concepts available in IP version four also apply in IP version six.
Now in this example we have both errata and a DHCP server.
Now the process for acquiring configuration data for a DHCP version six client is very similar to IP
version four.
However, initially, the client will first detect the presence of routers on the link by using neighbor
discovery messages.
If at least one router is found.
As in this diagram, the client will examine the router advertisements to determine if DHCP version
six should be used.
If there are advertisements, enable the use of DHCP version six on the link or if there's no router,
the client then starts a DHCP solicit phase to find a DHCP server.
So in this example, dhcp version six can be used so the host will send a DHCP solicit message to DHCP
version six agents.
In other words, dhcp servers using multicast address ff02.
Colon colon one.
Colon two.
Once again, just remember anything starting with ff02 is a multicast address.
We do not have broadcasts in IP version six.
So in the place of broadcasts, we're using specific multicast addresses.
The hosts will use a source address of F 80.
In other words, a link local address.
Now both DHCP servers and DHCP relays will listen for DHCP solicit messages on this multicast address.
So DHCP forwarding is very similar in IP version six as it's in IP version four.
Now, if the app cannot be used, the host reverts to stateless configuration as per the previous examples
I've shown you.
Now, without further ado, let's set up a basic IP version six network.
In this example, I have router one and router two.
Both routers have a fast Ethernet interface.
Rather, one's network on the foster ethernet interface is going to be 2001 colon.
One colon, one colon, one router two's FOSS Ethernet subnet is going to be 2001 colon one colon one
colon three.
The routers are connected via serial link and the subnet here is going to be 2001 colon, one colon,
one colon to notice.
Once again, the subnet mask is always slash 64 on all subnets.
Okay.
So on router one, I'm going to break out of the initial configuration dialog.
Go into global config mode and give the writer a name.
And then I'm going to enable IPV six unicast routing.
So that we can run IPv6 on this router.
And then I'm going to go on to f00, the first Ethernet interface and give it an address or IPV six.
And notice there are a lot of options here, but I'm going to specify address and then I'm going to
specify an IPV six address.
So 2001.
And in this case, I'm going to give the interface and address of one.
So it's as simple as that to configure an IP version six address on a router.
This portion is the network portion.
And notice we've got colon.
Colon.
So there are a bunch of zeros not displayed here.
And we ending in a one.
And then I can know.
Shut the interface.
And as you can see, the interface has come up.
So now I can do Ping 2001.
And ping the IP address.
And as you can see, the ping is successful on the serial zero interface.
I can do the same thing.
IPV six.
Address 2001.
Okay.
And on this side, I'm giving it an address of colon one.
And on this side, I'm going to give it an address of Colon two.
So in order to do the same thing, enable IPV six unicast routing.
And then on f00, give it an IPV six address of 2001.
No.
Shut the interface and serial zero zero.
Give it an address.
And I shot that interface.
So hopefully now from router to I should be able to ping router one.
That doesn't work because I forgot to know.
Shut the interface on the side so I'll.
No, shut it.
And go back to Rada, too.
And let's see if the ping succeeds this time.
Cat interface came up and as you can see, the ping succeeded.
It's as simple as that to configure IP addresses on a Cisco router.
Now on the fast Ethernet interface, I could give it another IP address so I could say IPv6 address.
Let's just be lazy.
Let's give it an address of 2001.
Colon, colon one slash 64.
And as you can see, the right is accepted.
That address on the right, I could not ping 2001 colon colon one.
And as you can see, the ping succeeds.
I could go back onto the interface and give it an address as follows IPV six address and let's say 2001
colon to colon.
Colon notice it gives you the option of link local address, but we don't want to do that.
Let's go for slash 64 notice, please.
I haven't put.
A host portion on this address.
I've just specified the network portion.
And now what I can do is I can specify UI 64 and hit enter.
So we're going to use the MAC address as part of that address.
So now I can type the command show run interface if zero zero to show you the configuration.
And as you can see, there's no IP version for address configured on this interface.
There are only IP version six addresses and they are three IP version six addresses that we have manually
configured.
I could then tap show interface if 0/0 the Mac address of this interface.
You see 4010fe8 followed by four zeros.
So the vendor portion of this address is c4010f and the unique portion is E eight, followed by four
zeros.
So just to display that nicely, I'm going to say show interface if zero zero type include a.
So it only shows that MAC address.
In the output.
And there it is.
And then I'm going to top show.
IPV six interface if zero zero and only include the addresses that we configured.
And they are the three IP addresses we configured on the interface.
So notice.
Yes, please.
We'll start from the right hand side.
The unique portion of the Mac address is E eight, followed by four zeros.
There it is in the IP address.
Remember, leading zeros can be dropped.
So this zero here represents those four zeros e eight.
Is the eat over there.
If if e has been inserted in the address to make it 64 bits and then notice the remaining portion is
c4010f.
Which is represented here as c601f.
Once again, leading zeros can be removed.
Notice the zero in front of this f has been removed.
Si 401 has been converted to c601 because the seventh bit has been changed to a one to represent that
this Mac address is globally unique.
So notice a IP address.
Is derived.
From the Mac address by using the UI representation of the MAC address.
Let's talk the command show, IPV six interface.
If 0/0.
And as you'll see here, notice there are three globally unique unicast addresses configured on the
interface.
Notice on this interface.
IPV six is enabled and there our link local address starting with feed and the UI portion of the address.
f02 Colon.
Colon one represents all nodes and routers on the link.
If zero to colon.
Colon two represents all routers on the link.
This is the solicited node multicast address used for mechanisms that replace OP.
In other words, this is the address used by duplicate address detection.
Or Dad.
There's a solicited node multicast address for each unique link ID.
So solicited node multicast addresses consist of f zero to colon colon one, colon f f and then the
unique portion of the interface ID.
So as an example, you can see this is 001.
Which is the same for this address and this address.
But yeah, notice we have f02 colon.
Colon one colon ffe80.
Because of this entry here, which is different to the previous addresses.