WEBVTT

1
00:00.000 --> 00:01.120 align:middle line:84%


2
00:01.120 --> 00:03.070 align:middle line:90%
One great way to learn
about a technology

3
00:03.070 --> 00:05.083 align:middle line:90%
is to identify what
problems it solve.

4
00:05.083 --> 00:07.000 align:middle line:90%
So, let's go to the
whiteboard and take a look

5
00:07.000 --> 00:10.210 align:middle line:90%
at a single router with four
interfaces with some very

6
00:10.210 --> 00:13.480 align:middle line:90%
interesting requirements
from the customer about what

7
00:13.480 --> 00:15.850 align:middle line:90%
they want to have
happen on that router.

8
00:15.850 --> 00:17.350 align:middle line:90%
So, let's imagine
that they've asked

9
00:17.350 --> 00:19.900 align:middle line:90%
us to unite to provision
a router with these four

10
00:19.900 --> 00:21.950 align:middle line:90%
interfaces and
these four networks.

11
00:21.950 --> 00:25.365 align:middle line:90%
So, we have the 10.100.0,
the 10.12.0, the 10.21.0,

12
00:25.365 --> 00:28.720 align:middle line:90%
and the 10.201.0 well
over 24 it masks.

13
00:28.720 --> 00:31.240 align:middle line:90%
So, we configure the
interfaces, we do know shut.
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

13
00:28.720 --> 00:31.240 align:middle line:90%
So, we configure the
interfaces, we do know shut.

14
00:31.240 --> 00:32.049 align:middle line:84%
It's all great.

15
00:32.049 --> 00:34.090 align:middle line:90%
We look at the routing
table and R1 says,

16
00:34.090 --> 00:36.340 align:middle line:90%
"Yep, I'm directly connected
to these four networks,

17
00:36.340 --> 00:38.437 align:middle line:90%
and R1 can route between
them, no problem."

18
00:38.437 --> 00:40.770 align:middle line:90%
So, we show up all happy,
happy and we say, "Great, it's

19
00:40.770 --> 00:41.690 align:middle line:84%
all ready to go."

20
00:41.690 --> 00:43.688 align:middle line:90%
And then the customer
says, "Oh, by the way

21
00:43.688 --> 00:45.480 align:middle line:90%
there's a couple of
additional requirements

22
00:45.480 --> 00:48.590 align:middle line:90%
I forgot to tell you
about and here they are."

23
00:48.590 --> 00:50.840 align:middle line:90%
So, as we draw this topology
the customer says, "Well,

24
00:50.840 --> 00:52.965 align:middle line:90%
actually what's happening
is we've got two separate

25
00:52.965 --> 00:55.900 align:middle line:90%
businesses and one business
we're going to have use these

26
00:55.900 --> 00:59.620 align:middle line:90%
two networks, the
10.100.0 and the 10.12.0.

27
00:59.620 --> 01:01.780 align:middle line:90%
And we want devices
on those two networks
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

27
00:59.620 --> 01:01.780 align:middle line:90%
And we want devices
on those two networks

28
01:01.780 --> 01:04.300 align:middle line:90%
to build communicate back
and forth no problem."

29
01:04.300 --> 01:06.010 align:middle line:90%
And then behind the
scenes, the customer

30
01:06.010 --> 01:09.220 align:middle line:90%
continues, "We have a second
business that we want to run

31
01:09.220 --> 01:10.960 align:middle line:90%
that is going to
use this 10.201 one

32
01:10.960 --> 01:12.910 align:middle line:84%
network and the 10.21 network.

33
01:12.910 --> 01:15.828 align:middle line:90%
And we want devices like this
PC and this PC and this PC

34
01:15.828 --> 01:18.370 align:middle line:90%
all to be able to communicate
with each other between the two

35
01:18.370 --> 01:19.060 align:middle line:84%
networks.

36
01:19.060 --> 01:21.640 align:middle line:90%
But we don't want to
have any communication

37
01:21.640 --> 01:24.430 align:middle line:90%
between these networks up
here in blue and the networks

38
01:24.430 --> 01:25.460 align:middle line:84%
down here."

39
01:25.460 --> 01:29.140 align:middle line:90%
So, I will draw a
red line to say,

40
01:29.140 --> 01:31.930 align:middle line:90%
"No communication between
the network circled in blue
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

40
01:29.140 --> 01:31.930 align:middle line:90%
"No communication between
the network circled in blue

41
01:31.930 --> 01:33.920 align:middle line:90%
and the network circled
in pink down here."

42
01:33.920 --> 01:36.110 align:middle line:90%
So, as you and I consider
that, what can we do?

43
01:36.110 --> 01:40.510 align:middle line:90%
Well, we could put access
control list like everywhere

44
01:40.510 --> 01:42.160 align:middle line:90%
on the interfaces
specifying what's

45
01:42.160 --> 01:43.960 align:middle line:84%
permitted or not permitted.

46
01:43.960 --> 01:45.465 align:middle line:90%
But that doesn't
scale very well,

47
01:45.465 --> 01:46.840 align:middle line:90%
those can be
really, really ugly.

48
01:46.840 --> 01:48.460 align:middle line:90%
Is there another
option that we can

49
01:48.460 --> 01:52.190 align:middle line:90%
use to help isolate or
segregate those networks,

50
01:52.190 --> 01:55.120 align:middle line:90%
so there's no communications
between the blue networks

51
01:55.120 --> 01:56.200 align:middle line:84%
and the pink networks?

52
01:56.200 --> 01:58.420 align:middle line:90%
And the answer is,
yes, and that's

53
01:58.420 --> 02:01.540 align:middle line:90%
exactly where VRF, virtual
routing and forwarding
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

53
01:58.420 --> 02:01.540 align:middle line:90%
exactly where VRF, virtual
routing and forwarding

54
02:01.540 --> 02:03.670 align:middle line:84%
instances can save the day.

55
02:03.670 --> 02:06.340 align:middle line:90%
And here's how they can
help, instead of just using

56
02:06.340 --> 02:08.598 align:middle line:90%
the single routing table
on the router, like we've

57
02:08.598 --> 02:11.140 align:middle line:90%
seen forever, like we do a show
IP route, all the routes that

58
02:11.140 --> 02:11.890 align:middle line:84%
show up.

59
02:11.890 --> 02:14.860 align:middle line:90%
That's referred to as
the global routing table,

60
02:14.860 --> 02:17.090 align:middle line:90%
you can get think of it as
the default routing table.

61
02:17.090 --> 02:19.720 align:middle line:90%
So, if we have interfaces
that we bring up

62
02:19.720 --> 02:21.353 align:middle line:90%
those directly
connected networks,

63
02:21.353 --> 02:23.770 align:middle line:90%
those routes for those directly
connected networks show up

64
02:23.770 --> 02:26.230 align:middle line:90%
in the global routing
table by default.

65
02:26.230 --> 02:29.080 align:middle line:90%
But instead of using that global
routing table, what we could do

66
02:29.080 --> 02:32.590 align:middle line:90%
is we could create two separate,
I think of them like a mini me
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

66
02:29.080 --> 02:32.590 align:middle line:90%
is we could create two separate,
I think of them like a mini me

67
02:32.590 --> 02:34.120 align:middle line:84%
version of a routing table.

68
02:34.120 --> 02:36.160 align:middle line:90%
And these little separate
sub routing tables

69
02:36.160 --> 02:40.630 align:middle line:90%
are referred to as
VRFs, virtual routing

70
02:40.630 --> 02:42.070 align:middle line:84%
and forwarding instances.

71
02:42.070 --> 02:44.770 align:middle line:90%
When you see VRF,
think of a small

72
02:44.770 --> 02:48.573 align:middle line:90%
and it doesn't have to be
small but a sub routing table.

73
02:48.573 --> 02:49.990 align:middle line:90%
So, if we had this
situation where

74
02:49.990 --> 02:51.870 align:middle line:90%
we need all these
routes to build

75
02:51.870 --> 02:54.520 align:middle line:90%
the routable between
each other and these

76
02:54.520 --> 02:56.470 align:middle line:90%
routes to be routable
between each other.

77
02:56.470 --> 03:00.648 align:middle line:90%
We could create two specific and
separate VRFs, virtual routing
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

77
02:56.470 --> 03:00.648 align:middle line:90%
We could create two specific and
separate VRFs, virtual routing

78
03:00.648 --> 03:01.690 align:middle line:84%
and forwarding instances.

79
03:01.690 --> 03:04.930 align:middle line:90%
That be one VRF that we could
create for the routes that

80
03:04.930 --> 03:08.230 align:middle line:90%
are here in blue, and we can
create a second, another VRF,

81
03:08.230 --> 03:09.940 align:middle line:90%
a virtual routing and
forwarding instance

82
03:09.940 --> 03:11.890 align:middle line:90%
for the routes here
that are in purple.

83
03:11.890 --> 03:14.740 align:middle line:90%
And the way it works is, once
we create these two VRFs,

84
03:14.740 --> 03:16.820 align:middle line:90%
I put them in color
coded to make it easier.

85
03:16.820 --> 03:19.810 align:middle line:90%
We create the two VRFs and
then at the interfaces,

86
03:19.810 --> 03:22.120 align:middle line:90%
we tell the
interfaces, "Hey, you

87
03:22.120 --> 03:24.380 align:middle line:90%
don't belong to the
global routing table,

88
03:24.380 --> 03:28.390 align:middle line:90%
I want you Mr. Interface
to belong to this VRF,"

89
03:28.390 --> 03:31.380 align:middle line:90%
and we go to 0/1, you
belong to this VRF.
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

89
03:28.390 --> 03:31.380 align:middle line:90%
and we go to 0/1, you
belong to this VRF.

90
03:31.380 --> 03:34.810 align:middle line:90%
And then for 0/2 we'd say, "You
belong to the purple or pink

91
03:34.810 --> 03:37.540 align:middle line:90%
or whatever color
that is, this VRF.

92
03:37.540 --> 03:39.880 align:middle line:84%
And 0/3 you belong to this VRF."

93
03:39.880 --> 03:42.700 align:middle line:90%
And then as a result of that
those directly connected

94
03:42.700 --> 03:46.420 align:middle line:90%
networks on 0/2 and 0/3 would be
part of this little VRF routing

95
03:46.420 --> 03:47.390 align:middle line:84%
table.

96
03:47.390 --> 03:50.142 align:middle line:90%
And the 0/0 and 0/1
whatever those IP networks

97
03:50.142 --> 03:51.850 align:middle line:90%
that it's directly
connected to, would be

98
03:51.850 --> 03:54.460 align:middle line:84%
part of this VRF, the blue VRF.

99
03:54.460 --> 03:57.025 align:middle line:90%
And the cool thing is this
interface right here like 0/0,

100
03:57.025 --> 03:59.290 align:middle line:90%
it can't belong to
multiple routing tables.

101
03:59.290 --> 04:01.930 align:middle line:90%
It can belong to the global
routing table by default
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

101
03:59.290 --> 04:01.930 align:middle line:90%
It can belong to the global
routing table by default

102
04:01.930 --> 04:06.130 align:middle line:90%
or it can belong to we'll
call this VRF A up here

103
04:06.130 --> 04:08.830 align:middle line:90%
or it can belong to VRF
B, but it can't belong

104
04:08.830 --> 04:10.280 align:middle line:84%
to more than one at a time.

105
04:10.280 --> 04:13.510 align:middle line:90%
So, it's either the global
routing table or a VRF

106
04:13.510 --> 04:14.380 align:middle line:84%
and that's it.

107
04:14.380 --> 04:16.959 align:middle line:90%
Now, a VRF is a
great tool to help

108
04:16.959 --> 04:20.019 align:middle line:90%
keep a set of routes isolated
and in service provider

109
04:20.019 --> 04:23.500 align:middle line:90%
networks with techniques
like MPLS layer 3 VPNs

110
04:23.500 --> 04:26.148 align:middle line:90%
they're going to use VRFs
as part of their solution.

111
04:26.148 --> 04:28.690 align:middle line:90%
Because they may have like 15
different customers and they're

112
04:28.690 --> 04:31.810 align:middle line:90%
going to have separate VRFs
for each of their customers
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

112
04:28.690 --> 04:31.810 align:middle line:90%
going to have separate VRFs
for each of their customers

113
04:31.810 --> 04:33.340 align:middle line:90%
as part of their
overall solution.

114
04:33.340 --> 04:34.990 align:middle line:90%
Which leads me to
the reason why we

115
04:34.990 --> 04:37.450 align:middle line:84%
might call something VRF lite.

116
04:37.450 --> 04:40.203 align:middle line:90%
VRF lite is when we implement
virtual routing and forwarding

117
04:40.203 --> 04:41.620 align:middle line:90%
instances, like
we just discussed,

118
04:41.620 --> 04:45.460 align:middle line:90%
but we're not using it as part
of like an MPLS layer 3 VPN

119
04:45.460 --> 04:46.180 align:middle line:84%
solution.

120
04:46.180 --> 04:48.100 align:middle line:90%
We're just telling
our individual routers

121
04:48.100 --> 04:50.860 align:middle line:90%
that they've got these new
VRFs or associating interfaces

122
04:50.860 --> 04:51.580 align:middle line:84%
with those VRFs.

123
04:51.580 --> 04:53.080 align:middle line:90%
And as a result,
we're going to have

124
04:53.080 --> 04:56.200 align:middle line:90%
separate routing tables
for each of those VRFs

125
04:56.200 --> 04:57.337 align:middle line:84%
on a single router.

126
04:57.337 --> 04:59.170 align:middle line:90%
Another really great
way to think about this

127
04:59.170 --> 05:02.247 align:middle line:90%
is to remind ourselves of
how layer 2 switch works.
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

127
04:59.170 --> 05:02.247 align:middle line:90%
is to remind ourselves of
how layer 2 switch works.

128
05:02.247 --> 05:04.080 align:middle line:90%
If we get a layer 2
switch from the factory,

129
05:04.080 --> 05:05.940 align:middle line:90%
boom put on our desk
and power it up.

130
05:05.940 --> 05:07.770 align:middle line:84%
How many VLANs does it have?

131
05:07.770 --> 05:10.200 align:middle line:90%
Just one key, VLAN
1, but it's very

132
05:10.200 --> 05:12.750 align:middle line:90%
likely we're going to
carve up multiple VLANs

133
05:12.750 --> 05:14.580 align:middle line:84%
on that physical switch.

134
05:14.580 --> 05:17.580 align:middle line:90%
So, you have one physical
switch and multiple VLANs,

135
05:17.580 --> 05:19.110 align:middle line:84%
layer 2 broadcast domains.

136
05:19.110 --> 05:21.960 align:middle line:90%
But the same logic applies to
a router, if we got a router,

137
05:21.960 --> 05:23.100 align:middle line:84%
boom plugged it in.

138
05:23.100 --> 05:25.650 align:middle line:90%
How many routing tables
do we have for layer 3?

139
05:25.650 --> 05:27.580 align:middle line:90%
We have one, the
global routing table.

140
05:27.580 --> 05:30.960 align:middle line:90%
But if we wanted two
or three separate
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

140
05:27.580 --> 05:30.960 align:middle line:90%
But if we wanted two
or three separate

141
05:30.960 --> 05:33.930 align:middle line:90%
isolated routing tables
like virtual routing tables

142
05:33.930 --> 05:34.950 align:middle line:84%
on that router.

143
05:34.950 --> 05:37.950 align:middle line:90%
We simply create three
VRFs, virtual routing

144
05:37.950 --> 05:39.160 align:middle line:84%
and forwarding instances.

145
05:39.160 --> 05:41.070 align:middle line:90%
Think of a VRF like a
little routing table

146
05:41.070 --> 05:42.780 align:middle line:90%
and then we can
have that isolation,

147
05:42.780 --> 05:45.192 align:middle line:90%
separate routing tables
for each of our customers

148
05:45.192 --> 05:46.900 align:middle line:90%
or each of our businesses
or however want

149
05:46.900 --> 05:49.740 align:middle line:90%
to isolate that layer 3
routing on the router.

150
05:49.740 --> 05:51.990 align:middle line:90%
And when we do this in a
situation we're not involving

151
05:51.990 --> 05:55.610 align:middle line:90%
MPLS or layer 3 VPNs, they
refer to this partitioning

152
05:55.610 --> 05:57.360 align:middle line:90%
and creating of these
small routing tables

153
05:57.360 --> 06:00.480 align:middle line:84%
on the router as VRF lite.
WEBVTT
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:900000

153
05:57.360 --> 06:00.480 align:middle line:84%
on the router as VRF lite.

154
06:00.480 --> 06:03.960 align:middle line:90%
Think of lite means, we're not
using MPLS or layer 3 VPNs,

155
06:03.960 --> 06:06.420 align:middle line:90%
we're just doing VRFs
locally on a router.

156
06:06.420 --> 06:08.060 align:middle line:90%
All right, so in
the next video, I'd

157
06:08.060 --> 06:09.570 align:middle line:90%
like to share with
you the details

158
06:09.570 --> 06:12.540 align:middle line:90%
of how we would create the VRFs,
how we could implement them.

159
06:12.540 --> 06:14.272 align:middle line:90%
And then we'll proceed
to make a design

160
06:14.272 --> 06:16.230 align:middle line:90%
and then we'll start
implementing and verifying

161
06:16.230 --> 06:17.482 align:middle line:84%
our VRF lite together.

162
06:17.482 --> 06:18.940 align:middle line:90%
So, I'll see you
in the next video.

163
06:18.940 --> 06:21.480 align:middle line:90%
Meanwhile, I hope this has
been informative for you

164
06:21.480 --> 06:24.500 align:middle line:90%
and I'd like to thank
you for viewing.

165
06:24.500 --> 06:25.000 align:middle line:84%