[AUDIO LOGO]
So now we're going to jump in and talk
about IPv6 support over MPLS, specifically
with MPLS running over an IPv4-only core.
Now, we've already talked all about MPLS in this course.
So we'll of course just be focusing in on the IPv6 aspect.
Now, this isn't, again, exactly tunneling.
But it is encapsulation, which at the end of the day,
that's what tunneling is.
So we're going to take a look at the three different ways
of supporting IPv6 over MPLS.
Now, one of them, truth be told, there's not really
too much to talk about.
We'll see that as we jump in.
We really want to focus on our layer 3 options,
both for layer 3 forwarding and for layer 3 VPN.
So let's go ahead and jump in.
We'll take a look at all three methods,
but again, mostly focusing in on the layer 3 options.
So there are a few different options
for supporting IPv6 over MPLS, the first of which
is simply to run IPv6 over a traditional layer 2 VPN.
The next option is to support IPv6 directly on top of MPLS,
using something called 6PE.
And the final choice is IPv6 over layer 3 VPN.
And this is something we call 6VPE.
So let's take a look at each of these options.
Let's look at layer 2 VPN first because it is certainly
the easiest one to discuss.
The reason it's the easiest one to discuss
is, well, layer 2 VPN forwards frames at layer 2.
And as such, that means that the layer 3 payload--
again, IPv4 versus IPv6--
is completely irrelevant.
It doesn't care what it's carrying.
So we don't care what the actual payload is.
Therefore, absolutely nothing needs
to be done for supporting IPv6.
So if our devices support layer 2 VPN and that's
the technology we've chosen to implement,
we don't have to do anything.
We can just have the customers use IPv6.
So clearly, it's the layer 3 options
that are going to cause us to have some discussion.
So let's go ahead and jump into 6PE.
So let's talk about some of those attributes of MPLS
using 6PE.
The first thing-- and we've mentioned this a few times--
same as with tunnels, the PEs themselves
are going to have to be dual stack.
Once again, we have to talk to IPv4 on the underlay.
And we have to talk IPv6 to the end networks
and over MPLS itself.
Now, the P routers, the provider routers in the core,
do not need IPv6 support.
This is sort of the point and why
we're talking about sending this over an IPv4-only core.
The P routers are not going to be involved in the IPv6.
What we do instead is we add to multiprotocol BGP the ability
to carry these IPv6 routes and the associated
labels between the PEs, much like we
do when we start talking about VPNs in layer 3 VPN.
Now, at the end of the day, remember, this is still MPLS.
So the core data plane is still just doing label switching.
That's why we need these labels up here for the IPv6 prefixes.
Now, much like VPN, this is going
to have to use two labels.
The first label, or the top label,
is, just like in VPN, to get us to the egress PE.
Once we get to the egress PE, that second label
is going to be to identify which IPv6 prefix this is for.
And the other thing that gets a little bit tricky
is what to use for the BGP next hop.
If we're going to be sending this stuff through BGP,
it needs a next hop, and it has to be
something we know how to use.
So the IPv6 next hop is going to be
what's called an IPv4-mapped IPv6 address.
Well, what does that mean?
Well, it means that we're going to take colon colon FFFF.
And we're simply going to put that
in front of the IPv4 address that represents
the egress PE's IPv4 address.
And that's what it's going to use for the IPv6 next hop.
And all of this works fine because the devices understand
that they're pulling the IPv4 address out of the IPv6-mapped
address.
As far as configuration for 6PE, if we look at IOS XR,
we see that the main thing we need to do is under BGP,
we need to go into the address-family ipv6 unicast
and add this statement-- allocate-label
for all prefixes.
Then under our neighbor statement,
we enable address-family ipv6, and we configure it
for labeled-unicast.
For IOS XE, it's actually a little bit easier.
All we have to do is go into address-family ipv6,
activate that neighbor because IPv6 would not
be normally activated to a neighborship,
and add the neighbor, and say send-label.
So this is all we need to do on IOS XE.
Now, our third choice is to do IPv6
over layer 3 VPN, also known as 6VPE.
Now, here's the cool thing about this feature.
This is exactly the same as IPv4 layer 3 VPN.
And of course, we've been over that in great detail
in our MPLS skills.
So we should already know how to configure IPv4 L3 VPN.
So all we need to do is add a new address family, VPNv6,
which is almost exactly the same as VPNv4.
It simply adds the route distinguisher
to the front of the IPv6 route.
And then we pretty much just duplicate the configuration,
adding IPv6 to, again, that same configuration
that we used for IPv4 L3 VPN.
So let's go ahead and take a look.
So the configuration for IOS XR, we
can see a few things we need to do.
We have to go into our VRF.
And we have to enable the address-family ipv6.
Under our BGP process, we have to add
the address-family vpnv6.
We have to go into the neighbor and add the address-family
to the neighborship.
And then whatever IGP we're using--
we can see in this example, we used OSPF version three.
But we then have to go into the BGP
instance of the VRF and configure whatever
redistribution we need to do.
So here we can see we're redistributing OSPF version
3, process 1 into BGP.
And here at the bottom, we can see
that we go into router ospfv3.
And for the VRF Customer A, we redistribute bgp.
So this is the same configuration
that we would do for IPv4.
We're just duplicating it for IPv6.
And the same with IOS XE.
We have to go into our VRF.
We have to add the address-family ipv6.
We go into BGP.
We enable the address-family vpnv6.
We activate that for the neighbor.
We tell it to send both communities.
Again, we only need extended communities,
but I generally enable both.
And then we do our redistribution again--
OSPF into BGP and then BGP into OSPF.
So as you can see, both of these configurations
are almost identical to what we do for IPv4.
We're just doing it for the address family IPv6 and VPNv6.
So in this video we looked at three different choices
we have for transporting IPv6 over MPLS
running over an IPv4-only core.
So our first option, again, was simply layer 2 VPN.
Layer 2 VPN doesn't care what the layer 3 payload is.
Therefore, you can forward IPv6 just
as easily as you can configure IPv4 or, really,
any other protocol, as long as it's supported on our networks.
The next choice is, of course, layer 3
directly on top of MPLS.
In that case, what we call 6PE is used to forward the traffic.
And we simply carry the extra information
in multiprotocol BGP.
Finally, we have almost the exact same thing,
but now it's 6VPE because now we're implementing VRFs.
And these function exactly like layer 3
VPN does for IPv4, just supporting IPv6.
So that takes care of everything that we
need to discuss in this skill.
That leaves us with nothing else to cover except for a review
in the form of a quiz.
And that's exactly what we're going to do next.
Till then, I hope this has been informative for you,
and I'd like to thank you for viewing.