1
00:00:02,809 --> 00:00:05,476
(intense music)

2
00:00:08,845 --> 00:00:12,224
- Okay, here we are on Part
3 of our CCNA Switch Lab,

3
00:00:12,224 --> 00:00:14,564
and now we're finally gonna
start doing some switching stuff

4
00:00:14,564 --> 00:00:18,237
by jumping over to those
EtherSwitch modules and our Routers

5
00:00:18,237 --> 00:00:21,344
and configuring the
switching component of that.

6
00:00:21,344 --> 00:00:25,684
So, here we're gonna configure
VTP and VLANS on the routers.

7
00:00:25,684 --> 00:00:27,369
By the time we're done with this,

8
00:00:27,369 --> 00:00:31,581
we should have end-to-end
connectivity all the way across,

9
00:00:31,581 --> 00:00:34,010
from one router to the
other at the far side.

10
00:00:34,010 --> 00:00:36,079
We won't be done yet, because
we still have to manipulate

11
00:00:36,079 --> 00:00:37,926
a little spanning tree,

12
00:00:37,926 --> 00:00:39,828
we'll do that in the final video,

13
00:00:39,828 --> 00:00:41,631
but we should have end-to-end connectivity

14
00:00:41,631 --> 00:00:45,016
by the time we're done with
the required tasks here.

15
00:00:45,016 --> 00:00:48,169
Okay, so looking at our topology diagram.

16
00:00:48,169 --> 00:00:50,453
We can see that right
now, what's left for us

17
00:00:50,453 --> 00:00:53,198
is that we have to configure VLANs 4 and 5

18
00:00:53,198 --> 00:00:55,728
in this router right here.

19
00:00:55,728 --> 00:00:57,777
We wanna make sure that VTP is set up

20
00:00:57,777 --> 00:00:59,313
so this guy's a client,

21
00:00:59,313 --> 00:01:01,480
and he learns of the VLANs

22
00:01:02,526 --> 00:01:03,359
via VTP.

23
00:01:04,550 --> 00:01:08,383
So let's start with VTP
and then do the VLANs.

24
00:01:11,109 --> 00:01:14,553
So I'm gonna go on to
the EtherSwitch Router 2,

25
00:01:14,553 --> 00:01:16,258
which in this particular case...

26
00:01:16,258 --> 00:01:18,271
Now before I do this,

27
00:01:18,271 --> 00:01:21,294
I've been saving my
configs all along the way,

28
00:01:21,294 --> 00:01:22,852
so I'm gonna take a snapshot.

29
00:01:22,852 --> 00:01:26,095
I'm gonna turn everybody off,

30
00:01:26,095 --> 00:01:28,244
take a snapshot right now,

31
00:01:28,244 --> 00:01:29,827
and we'll call this

32
00:01:31,804 --> 00:01:33,054
No-VLAN-or-STP.

33
00:01:39,775 --> 00:01:43,775
Okay, close, let's bring
everything back online.

34
00:01:45,659 --> 00:01:47,802
The majority of the configuration for this

35
00:01:47,802 --> 00:01:51,079
is gonna be between EtherSwitch
1 and EtherSwitch 2.

36
00:01:51,079 --> 00:01:54,246
So, let's just bring both of those up.

37
00:02:00,034 --> 00:02:04,201
Alright, let's put them
in the correct order here.

38
00:02:10,034 --> 00:02:12,771
Okay, EtherSwitch 1,
which is the guy on top.

39
00:02:12,771 --> 00:02:16,854
Let's start with EtherSwitch
2 as the VTP client.

40
00:02:20,136 --> 00:02:22,382
So, here with VTP, first we have to create

41
00:02:22,382 --> 00:02:23,882
a VTP domain name.

42
00:02:24,786 --> 00:02:26,703
We'll just give it INE.

43
00:02:27,765 --> 00:02:30,432
And we'll make it the same here.

44
00:02:32,580 --> 00:02:33,413
Okay.

45
00:02:35,978 --> 00:02:38,914
EtherSwitch 1 is gonna be
a VTP server by default,

46
00:02:38,914 --> 00:02:41,248
because that's the way Cisco works it,

47
00:02:41,248 --> 00:02:45,393
so we just have to configure EtherSwitch 2

48
00:02:45,393 --> 00:02:46,393
as a client.

49
00:02:48,838 --> 00:02:50,014
Okay, great.

50
00:02:50,014 --> 00:02:51,429
Now, in order for VTP to work,

51
00:02:51,429 --> 00:02:55,793
it has to work over
functional VLAN trunks.

52
00:02:55,793 --> 00:02:57,693
Now, these EtherSwitch modules,

53
00:02:57,693 --> 00:03:00,026
unlike real physical switches,

54
00:03:00,026 --> 00:03:03,218
do not support the
dynamic trunking protocol.

55
00:03:03,218 --> 00:03:05,539
If these were real switches,
the lengths between them

56
00:03:05,539 --> 00:03:09,392
quite possibly would
already be 802.1q trunks,

57
00:03:09,392 --> 00:03:11,144
without us having to do anything.

58
00:03:11,144 --> 00:03:14,568
Because they probably dynamic
and have exchanged DTP.

59
00:03:14,568 --> 00:03:15,762
Or maybe not.

60
00:03:15,762 --> 00:03:18,600
But in this particular case,
in order to form a trunk,

61
00:03:18,600 --> 00:03:21,201
we have to manually do it
on EtherSwitch modules.

62
00:03:21,201 --> 00:03:24,223
We cannot use dynamic
desirable, or dynamic auto.

63
00:03:24,223 --> 00:03:26,491
Those keywords don't even exist for us.

64
00:03:26,491 --> 00:03:28,258
So, that being the case,

65
00:03:28,258 --> 00:03:30,208
if I go back to my topology diagram,

66
00:03:30,208 --> 00:03:34,738
we've got 1/9 and 1/15.

67
00:03:34,738 --> 00:03:38,365
So I'll just go ahead and use
the Interface Range command

68
00:03:38,365 --> 00:03:39,732
for that.

69
00:03:39,732 --> 00:03:42,502
Interface range, fast Ethernet 1/9,

70
00:03:42,502 --> 00:03:44,743
and because it's a non-contiguous range,

71
00:03:44,743 --> 00:03:47,504
I have to use the comma.

72
00:03:47,504 --> 00:03:50,921
And we'll just say switchport mode trunk.

73
00:03:52,371 --> 00:03:54,954
No shut, just for good measure.

74
00:03:55,869 --> 00:03:57,786
Save our configuration.

75
00:03:59,230 --> 00:04:01,770
Okay, so that's EtherSwitch 2.

76
00:04:01,770 --> 00:04:03,815
Now, let's just do the same thing

77
00:04:03,815 --> 00:04:05,169
in EtherSwitch 1.

78
00:04:05,169 --> 00:04:09,336
Interface range, fast Ethernet 1/9, 1/15.

79
00:04:12,154 --> 00:04:13,987
Switchport mode trunk.

80
00:04:17,157 --> 00:04:17,990
Save it.

81
00:04:20,554 --> 00:04:23,049
Okay, and for the CCNA
Routing and Switching exam,

82
00:04:23,049 --> 00:04:25,784
you should be aware of
what command you would type

83
00:04:25,784 --> 00:04:29,323
to verify if the trunks
are actually functional.

84
00:04:29,323 --> 00:04:30,979
There's actually a couple
things you could do,

85
00:04:30,979 --> 00:04:35,428
but my favorite command
is show interfaces trunk.

86
00:04:35,428 --> 00:04:37,474
And it shows us,

87
00:04:37,474 --> 00:04:38,391
right here.

88
00:04:39,339 --> 00:04:41,284
You could also do show interface,

89
00:04:41,284 --> 00:04:43,494
type in the interface name,

90
00:04:43,494 --> 00:04:45,836
and then switchport.

91
00:04:45,836 --> 00:04:48,985
And what you're looking
for is operational mode.

92
00:04:48,985 --> 00:04:52,226
Administrative mode means,
what am I configured to do?

93
00:04:52,226 --> 00:04:56,466
Operational mode means,
what am I actually doing?

94
00:04:56,466 --> 00:04:59,328
And right now, it says, trunk.

95
00:04:59,328 --> 00:05:00,294
So, we're good to go there.

96
00:05:00,294 --> 00:05:02,076
So now the last thing we
should be able to do is

97
00:05:02,076 --> 00:05:04,386
here in our VTP server,

98
00:05:04,386 --> 00:05:07,096
we should be able to create our two VLANs,

99
00:05:07,096 --> 00:05:11,339
VLANs 4 and 5, and we should
see them propagated downstream

100
00:05:11,339 --> 00:05:12,839
to our VTP client.

101
00:05:14,179 --> 00:05:15,012
Vlan 4-5.

102
00:05:20,424 --> 00:05:25,071
That allows us to create
multiple VLANs at the same time.

103
00:05:25,071 --> 00:05:26,988
Save our configuration.

104
00:05:28,408 --> 00:05:30,145
Now, if we were in a regular switch,

105
00:05:30,145 --> 00:05:32,290
we could just do the show VLAN command

106
00:05:32,290 --> 00:05:35,259
to see what VLANs are in here.

107
00:05:35,259 --> 00:05:38,264
But in this particular case,

108
00:05:38,264 --> 00:05:40,847
we have to do show VLAN-switch,

109
00:05:44,325 --> 00:05:48,492
and we can see that VLANs
4 and 5 have been created.

110
00:05:50,059 --> 00:05:52,299
Show interface trunk,

111
00:05:52,299 --> 00:05:55,324
verifies for us that those
VLANs are allowed on the trunk.

112
00:05:55,324 --> 00:05:57,881
They're actually, right
now, they are active.

113
00:05:57,881 --> 00:05:59,079
We can see that.

114
00:05:59,079 --> 00:06:01,541
And so now if we go down to switch 2,

115
00:06:01,541 --> 00:06:05,541
hopefully it has learned
of those VLANs via VTP.

116
00:06:06,674 --> 00:06:08,091
Show VLAN-switch.

117
00:06:10,684 --> 00:06:11,601
And he has.

118
00:06:12,563 --> 00:06:14,923
He has learned of those.

119
00:06:14,923 --> 00:06:17,486
Save our configuration.

120
00:06:17,486 --> 00:06:20,134
So, at this point now,
our trunks are functional

121
00:06:20,134 --> 00:06:21,651
all the way across.

122
00:06:21,651 --> 00:06:23,957
Whatever VLANs we are going to be using

123
00:06:23,957 --> 00:06:27,785
have been configured and
have been propagated.

124
00:06:27,785 --> 00:06:29,785
If we go to our diagram,

125
00:06:30,996 --> 00:06:34,206
Router 1 now should be able to ping

126
00:06:34,206 --> 00:06:38,037
either one of these IP
address on Router 3,

127
00:06:38,037 --> 00:06:40,889
and he should be able
to get a response back.

128
00:06:40,889 --> 00:06:44,306
So, let's see if that is indeed the case.

129
00:06:53,870 --> 00:06:56,620
Alright, let's bring up Router 1.

130
00:07:00,900 --> 00:07:03,175
Here's the moment of truth,

131
00:07:03,175 --> 00:07:04,258
ping 2.3.2.3.

132
00:07:12,540 --> 00:07:13,866
Okay, this is good though.

133
00:07:13,866 --> 00:07:15,251
This is gonna give us a
little bit of troubleshooting

134
00:07:15,251 --> 00:07:16,314
experience.

135
00:07:16,314 --> 00:07:17,797
Okay, so step number one.

136
00:07:17,797 --> 00:07:20,192
We previously configured
some static routes in here,

137
00:07:20,192 --> 00:07:21,254
but let's verify.

138
00:07:21,254 --> 00:07:23,711
Does he actually have the
routing information to get there?

139
00:07:23,711 --> 00:07:24,878
Show IP route.

140
00:07:27,061 --> 00:07:30,386
Okay, so he does have a static route.

141
00:07:30,386 --> 00:07:32,562
Can he ping his neighbor?

142
00:07:32,562 --> 00:07:34,189
His next hop neighbor.

143
00:07:34,189 --> 00:07:35,272
Ping 1.2.4.2.

144
00:07:38,925 --> 00:07:41,528
Okay, he is not pinging.

145
00:07:41,528 --> 00:07:43,112
Ah, I think I know what the problem is.

146
00:07:43,112 --> 00:07:45,711
We forgot one little step, I believe.

147
00:07:45,711 --> 00:07:47,671
I think the problem is

148
00:07:47,671 --> 00:07:50,527
we forgot to configure
this interface right here

149
00:07:50,527 --> 00:07:52,860
on EtherSwitch 2 as a trunk.

150
00:07:54,248 --> 00:07:55,912
I think that's our problem.

151
00:07:55,912 --> 00:07:59,555
So let's go back to EtherSwitch 2.

152
00:07:59,555 --> 00:08:03,025
Show run interface fast Ethernet 1/0.

153
00:08:03,025 --> 00:08:06,659
And yes, it is not configured as a trunk.

154
00:08:06,659 --> 00:08:10,826
Okay, so, config T
interface fast Ethernet 1/0.

155
00:08:12,314 --> 00:08:14,147
Switchport mode trunk.

156
00:08:15,972 --> 00:08:19,055
And that should be all we have to do.

157
00:08:21,274 --> 00:08:24,024
Now, it's carrying all the VLANs.

158
00:08:25,242 --> 00:08:27,321
So now, we should be able to ping,

159
00:08:27,321 --> 00:08:30,738
Router 1 should be able to ping Router 2.

160
00:08:34,871 --> 00:08:35,861
Might take a little bit of time,

161
00:08:35,861 --> 00:08:37,753
cause remember spanning
tree has to converge

162
00:08:37,753 --> 00:08:40,136
and go from listening to
learning to forwarding,

163
00:08:40,136 --> 00:08:43,136
and that takes a little bit of time.

164
00:08:51,764 --> 00:08:54,544
Let's verify that spanning
tree for VLANs 4 and 5

165
00:08:54,544 --> 00:08:56,856
does have a forwarding path.

166
00:08:56,856 --> 00:08:58,966
So what we should see...

167
00:08:58,966 --> 00:09:00,764
I don't know which one of these switches

168
00:09:00,764 --> 00:09:02,099
is gonna be the spanning tree root bridge,

169
00:09:02,099 --> 00:09:04,392
we'll get into that in the very
last video of this section,

170
00:09:04,392 --> 00:09:07,560
but what we should see
is that VLANs 4 and 5

171
00:09:07,560 --> 00:09:09,125
are both allowed on this interface

172
00:09:09,125 --> 00:09:10,528
because it's trunking.

173
00:09:10,528 --> 00:09:12,636
This interface should be
in the forwarding state.

174
00:09:12,636 --> 00:09:16,578
It should be designated
for both VLANs 4 and 5.

175
00:09:16,578 --> 00:09:17,612
Same thing over here.

176
00:09:17,612 --> 00:09:19,397
Ah, I think that's the other problem.

177
00:09:19,397 --> 00:09:22,950
I forgot to configure
this as an 802.1q trunk.

178
00:09:22,950 --> 00:09:24,843
That's probably what's the problem.

179
00:09:24,843 --> 00:09:27,593
Let's go over to my diagram here,

180
00:09:28,891 --> 00:09:30,247
my GNS-3,

181
00:09:30,247 --> 00:09:34,414
and I need to configure fast
Ethernet 1/0 on EtherSwitch 1.

182
00:09:38,276 --> 00:09:40,109
Switchport mode trunk.

183
00:09:44,756 --> 00:09:47,660
Alright, let's wait for it to
go into the forwarding state.

184
00:09:47,660 --> 00:09:51,827
Show spanning-tree,
interface fast Ethernet 1/0.

185
00:09:52,963 --> 00:09:56,213
Right now it says that it is listening,

186
00:09:58,552 --> 00:10:02,219
so we have to wait until
it goes forwarding.

187
00:10:03,281 --> 00:10:05,198
And now it is learning,

188
00:10:12,416 --> 00:10:13,883
and now it is forwarding.

189
00:10:13,883 --> 00:10:18,050
Alright, so now, we should
have end-to-end connectivity.

190
00:10:20,267 --> 00:10:23,684
First of all, can Router 1 ping Router 2.

191
00:10:29,228 --> 00:10:33,395
Well, we might need a little
more troubleshooting here.

192
00:10:45,014 --> 00:10:47,708
Alright, let's see if we
can troubleshoot this.

193
00:10:47,708 --> 00:10:49,322
Starting with the physical layer.

194
00:10:49,322 --> 00:10:51,322
Show IP interface brief.

195
00:10:53,186 --> 00:10:57,598
And fast Ethernet 0/0 is
what we're looking for.

196
00:10:57,598 --> 00:10:59,042
It is up,

197
00:10:59,042 --> 00:11:01,179
the very subinterfaces are up.

198
00:11:01,179 --> 00:11:04,510
And the very subinterfaces
have been allocated

199
00:11:04,510 --> 00:11:07,357
that IP addresses in the correct

200
00:11:07,357 --> 00:11:09,417
VLANs and subnets,

201
00:11:09,417 --> 00:11:10,578
so, that looks right.

202
00:11:10,578 --> 00:11:14,745
We already confirmed that he
has the correct static routes.

203
00:11:18,517 --> 00:11:22,100
Okay, so there's nothing
wrong on Router 1.

204
00:11:24,109 --> 00:11:25,691
Okay, let's move down the chain now.

205
00:11:25,691 --> 00:11:28,972
Let's go over to EtherSwitch 2.

206
00:11:28,972 --> 00:11:31,878
EtherSwitch 2, let's make
sure that fast Ethernet 1/0

207
00:11:31,878 --> 00:11:32,878
is trunking.

208
00:11:34,279 --> 00:11:38,985
Show interface fast
Ethernet 1/0, switchport.

209
00:11:38,985 --> 00:11:41,152
Operational mode is trunk.

210
00:11:42,329 --> 00:11:44,079
Show interface trunk.

211
00:11:45,692 --> 00:11:49,859
1/0 is on, and it is
allowing VLANs 4 and 5.

212
00:11:50,757 --> 00:11:52,315
Okay, that's good.

213
00:11:52,315 --> 00:11:55,835
We also see these other two
interfaces leading upstream to

214
00:11:55,835 --> 00:12:00,002
EtherSwitch 1 are on, also
allowing VLANs 4 and 5.

215
00:12:01,133 --> 00:12:05,133
Let's look at the spanning
tree state of VLAN 4.

216
00:12:06,472 --> 00:12:10,051
VLAN 4 is executing, basically, 802.1d,

217
00:12:10,051 --> 00:12:12,634
and what we're looking for here

218
00:12:13,617 --> 00:12:18,253
is it says that 1/0, which
goes down to Router 1,

219
00:12:18,253 --> 00:12:20,197
is forwarding.

220
00:12:20,197 --> 00:12:25,158
1/9, which goes upstream to EtherSwitch 1,

221
00:12:25,158 --> 00:12:26,670
is forwarding.

222
00:12:26,670 --> 00:12:28,677
And 1/15 is blocking.

223
00:12:28,677 --> 00:12:29,510
That's fine.

224
00:12:29,510 --> 00:12:31,411
We just need one of those
upstream interfaces.

225
00:12:31,411 --> 00:12:33,520
So, right now, the one here on the left

226
00:12:33,520 --> 00:12:35,838
is the one that's in the forwarding state.

227
00:12:35,838 --> 00:12:38,786
That's for VLAN 4, what about VLAN 5.

228
00:12:38,786 --> 00:12:42,604
I would expect VLAN 5 to
look exactly the same.

229
00:12:42,604 --> 00:12:45,037
Yep, the port going to
the router is forwarding,

230
00:12:45,037 --> 00:12:47,577
and the lower numbered port

231
00:12:47,577 --> 00:12:49,663
is forwarding going upstream.

232
00:12:49,663 --> 00:12:52,913
Everything looks fine on EtherSwitch 2.

233
00:12:55,407 --> 00:12:58,407
Now, let's go over to EtherSwitch 1.

234
00:13:00,988 --> 00:13:03,155
Show spanning-tree VLAN 4.

235
00:13:06,881 --> 00:13:11,048
Okay, so 1/0, which goes across
to Router 2 is forwarding.

236
00:13:12,130 --> 00:13:15,273
1/9 is forwarding,

237
00:13:15,273 --> 00:13:17,604
1/15 is forwarding.

238
00:13:17,604 --> 00:13:21,354
Okay, so this guy's
probably the root bridge.

239
00:13:22,934 --> 00:13:26,184
Okay, so, so far everything looks fine.

240
00:13:27,566 --> 00:13:30,486
Now let's go across to Router 2.

241
00:13:30,486 --> 00:13:32,569
Last thing to check here.

242
00:13:37,672 --> 00:13:41,839
Show run, let's take a look
at his fast Ethernet 0/0.

243
00:13:44,670 --> 00:13:47,068
Okay, ah, here's our problem.

244
00:13:47,068 --> 00:13:49,547
Fast Ethernet 0/0, I
forgot to bring it up.

245
00:13:49,547 --> 00:13:50,797
It's shut down.

246
00:13:55,920 --> 00:13:58,503
That could explain our problem.

247
00:14:00,862 --> 00:14:03,300
Show IP interface brief.

248
00:14:03,300 --> 00:14:06,318
Alright, fast Ethernet 0/0,
which is trunking, is up,

249
00:14:06,318 --> 00:14:09,537
and the other two interfaces are up.

250
00:14:09,537 --> 00:14:13,857
Okay, so now, which was a
good troubleshooting exercise,

251
00:14:13,857 --> 00:14:16,127
we should be able to ping

252
00:14:16,127 --> 00:14:18,025
end-to-end from R1.

253
00:14:18,025 --> 00:14:21,743
Ping 2.3.2.3, let's go for the gold here.

254
00:14:21,743 --> 00:14:24,243
Let's try to ping all the way.

255
00:14:25,565 --> 00:14:27,384
Come on, you can do it.

256
00:14:27,384 --> 00:14:28,877
There we go.

257
00:14:28,877 --> 00:14:30,282
Fantastic.

258
00:14:30,282 --> 00:14:33,032
And ping the other side, 3.2.3.3.

259
00:14:35,744 --> 00:14:37,338
He has to arp for it.

260
00:14:37,338 --> 00:14:39,245
Actually, he doesn't have to arp for it,

261
00:14:39,245 --> 00:14:41,677
he does have to arp for his next hop.

262
00:14:41,677 --> 00:14:43,760
And then we have success.

263
00:14:44,747 --> 00:14:48,276
Okay, so at this point, let me
bring the diagram over here.

264
00:14:48,276 --> 00:14:51,146
Let me just renumber these
interfaces for a second

265
00:14:51,146 --> 00:14:53,646
because these are not correct.

266
00:14:55,034 --> 00:14:56,367
Okay, so we have

267
00:14:57,433 --> 00:14:58,683
1/9,

268
00:14:59,625 --> 00:15:00,958
1/15,

269
00:15:02,333 --> 00:15:03,583
1/9,

270
00:15:04,783 --> 00:15:06,819
1/15,

271
00:15:06,819 --> 00:15:10,244
and this over here I believe is 1/0.

272
00:15:10,244 --> 00:15:11,690
Okay, so right now,

273
00:15:11,690 --> 00:15:13,977
because of the way spanning
tree is configured,

274
00:15:13,977 --> 00:15:15,508
by the way, just ended up,

275
00:15:15,508 --> 00:15:17,928
we didn't configure it this way,

276
00:15:17,928 --> 00:15:19,345
what we've got is

277
00:15:21,096 --> 00:15:24,513
this right here is in the blocking state.

278
00:15:27,744 --> 00:15:31,577
The remaining three
interfaces are forwarding.

279
00:15:34,763 --> 00:15:39,119
And so when Router 1
pings anything over here,

280
00:15:39,119 --> 00:15:41,180
everything he pings

281
00:15:41,180 --> 00:15:43,359
is gonna have to take the forwarding path.

282
00:15:43,359 --> 00:15:44,192
It's gonna go this way,

283
00:15:44,192 --> 00:15:47,308
both the pings and the reply packets.

284
00:15:47,308 --> 00:15:49,216
However, if you remember,

285
00:15:49,216 --> 00:15:52,466
if we go right back to our original lab

286
00:15:53,791 --> 00:15:56,374
specifications, our objectives,

287
00:15:57,375 --> 00:15:59,708
it said, as we can see here,

288
00:16:00,822 --> 00:16:04,698
ensure that packets sent
between Router 1 and Router 2

289
00:16:04,698 --> 00:16:08,398
traverse across the higher-numbered ports.

290
00:16:08,398 --> 00:16:09,989
So right now, it's going across

291
00:16:09,989 --> 00:16:12,671
the lowest-numbered ports, 1/9.

292
00:16:12,671 --> 00:16:15,236
But reality, we're supposed
to be having it go across

293
00:16:15,236 --> 00:16:17,740
the highest-numbered ports.

294
00:16:17,740 --> 00:16:19,134
Which in this case,

295
00:16:19,134 --> 00:16:22,555
means we need to somehow
get this path forwarding

296
00:16:22,555 --> 00:16:24,569
and this path blocking.

297
00:16:24,569 --> 00:16:26,432
And that's the last thing we're gonna do

298
00:16:26,432 --> 00:16:28,655
in the very next video.

299
00:16:28,655 --> 00:16:31,322
(intense music)