1
00:00:02,622 --> 00:00:05,372
(exciting music)

2
00:00:09,315 --> 00:00:11,809
- So let me go back to GNS3 here.

3
00:00:11,809 --> 00:00:14,950
So I've already preconfigured
all of this stuff.

4
00:00:14,950 --> 00:00:18,171
Let me go in and a couple of things here.

5
00:00:18,171 --> 00:00:21,193
If you're using GNS3 like I am,

6
00:00:21,193 --> 00:00:23,769
GNS3 is great for routing stuff.

7
00:00:23,769 --> 00:00:25,824
Pretty much anything you'd
ever need to do with routers,

8
00:00:25,824 --> 00:00:27,253
all the way up to pretty much the

9
00:00:27,253 --> 00:00:30,371
CCIE level, you could do in GNS3.

10
00:00:30,371 --> 00:00:32,544
Switching, it's kinda weak.

11
00:00:32,544 --> 00:00:34,545
It, there's a lot of switching

12
00:00:34,545 --> 00:00:37,002
features that you can't do.

13
00:00:37,002 --> 00:00:39,038
Most of what you need to know at the CCNA

14
00:00:39,038 --> 00:00:42,421
level, you can do with switches on GNS3,

15
00:00:42,421 --> 00:00:44,878
not everything but most everything.

16
00:00:44,878 --> 00:00:47,293
But once you get to the CCNP level,

17
00:00:47,293 --> 00:00:50,637
that's where GNS3
switching is really subpar.

18
00:00:50,637 --> 00:00:51,885
And it's not their fault.

19
00:00:51,885 --> 00:00:53,418
It's really the fault of, ya know, what

20
00:00:53,418 --> 00:00:57,585
software images are available
to put into this program.

21
00:00:59,304 --> 00:01:02,650
But that being said, I'm
not gonna really show

22
00:01:02,650 --> 00:01:04,220
you the router's configuration.

23
00:01:04,220 --> 00:01:05,347
I'll show you that in a second.

24
00:01:05,347 --> 00:01:07,480
Let me just start with the
switches configuration.

25
00:01:07,480 --> 00:01:10,935
Let's go here to EtherSwitch One

26
00:01:10,935 --> 00:01:13,394
and get rid of some of this other stuff.

27
00:01:13,394 --> 00:01:15,061
These are the hosts.

28
00:01:18,309 --> 00:01:21,492
Okay, so here in EtherSwitch One,

29
00:01:21,492 --> 00:01:24,394
because this is, what this really is,

30
00:01:24,394 --> 00:01:25,601
just so you know, 'cause you're gonna see

31
00:01:25,601 --> 00:01:28,986
a different command here
that you don't normally use.

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00:01:28,986 --> 00:01:33,013
Cisco sells some routers
and when it comes to

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00:01:33,013 --> 00:01:35,591
routers and switches, this is common.

34
00:01:35,591 --> 00:01:37,446
When you're buying a router or switch

35
00:01:37,446 --> 00:01:39,823
at a very high level, you have a choice.

36
00:01:39,823 --> 00:01:42,519
You can buy what's called
a fixed configuration

37
00:01:42,519 --> 00:01:46,952
chassis, what that means
is you're buying one box,

38
00:01:46,952 --> 00:01:48,683
all the interfaces or all the ports are

39
00:01:48,683 --> 00:01:52,147
on that box and that's what you get.

40
00:01:52,147 --> 00:01:55,127
So for example, let's
say you bought a switch

41
00:01:55,127 --> 00:01:59,454
that's a fixed configuration
chassis that has 24 ports.

42
00:01:59,454 --> 00:02:02,326
Well, let's say later on
as your network grows,

43
00:02:02,326 --> 00:02:06,440
all of a sudden, you've
used up all those 24 ports.

44
00:02:06,440 --> 00:02:09,223
You don't have any options, you
gotta go buy another switch.

45
00:02:09,223 --> 00:02:11,116
There's nothin' you can
do to that switch to

46
00:02:11,116 --> 00:02:14,946
give it more ports,
you've used up everything.

47
00:02:14,946 --> 00:02:17,968
Whereas in a modular
chassis, whether it be

48
00:02:17,968 --> 00:02:20,789
a router or a switch,
basically what you're buying

49
00:02:20,789 --> 00:02:23,407
is the box and then you get to choose what

50
00:02:23,407 --> 00:02:26,831
sort of modules you want to plug in there.

51
00:02:26,831 --> 00:02:30,018
Like maybe on a modular
switch, you say, okay,

52
00:02:30,018 --> 00:02:33,600
this switch could technically
have modules inside of it.

53
00:02:33,600 --> 00:02:36,181
Right now, I'm only gonna
spend money to buy one module

54
00:02:36,181 --> 00:02:38,800
that's a 24 port switching module.

55
00:02:38,800 --> 00:02:41,176
And then if I run out of ports, I'll order

56
00:02:41,176 --> 00:02:43,997
from Cisco another module
and in that same chassis

57
00:02:43,997 --> 00:02:48,246
I'll slide in another 24
port switching module.

58
00:02:48,246 --> 00:02:50,267
Or in the case of a
router, you can say, well,

59
00:02:50,267 --> 00:02:53,210
right now all I need are land modules.

60
00:02:53,210 --> 00:02:54,864
But later on, I'm gonna
pull out one of those

61
00:02:54,864 --> 00:02:56,716
land modules and I'm gonna put a wide area

62
00:02:56,716 --> 00:02:58,933
networking module in there or a firewall

63
00:02:58,933 --> 00:03:01,147
module or something like that.

64
00:03:01,147 --> 00:03:04,288
So modular switches and routers are better

65
00:03:04,288 --> 00:03:06,544
from the standpoint of scalability.

66
00:03:06,544 --> 00:03:08,639
You can start small and then purchase more

67
00:03:08,639 --> 00:03:10,452
things that you can plug in there,

68
00:03:10,452 --> 00:03:12,103
sort of like your laptop, right?

69
00:03:12,103 --> 00:03:14,318
When you buy your laptop,
it's got additional ports

70
00:03:14,318 --> 00:03:16,653
in it that are probably
not used for something.

71
00:03:16,653 --> 00:03:19,313
But later on, you can
stick a DVD drive in there,

72
00:03:19,313 --> 00:03:22,173
maybe stick in another
Ethernet card if you wanted to.

73
00:03:22,173 --> 00:03:24,108
Same thing with modular chassis.

74
00:03:24,108 --> 00:03:26,690
Of course, the down side
is, the modular chassis

75
00:03:26,690 --> 00:03:30,074
are typically more expensive
for that very reason.

76
00:03:30,074 --> 00:03:31,644
What does that have to do with this?

77
00:03:31,644 --> 00:03:35,389
Well, Cisco sells some
routers that are modular

78
00:03:35,389 --> 00:03:38,046
routers and some of the
modules you can put in

79
00:03:38,046 --> 00:03:40,986
there if you want to
are switching modules.

80
00:03:40,986 --> 00:03:43,121
It's actually a little
module you can slide in

81
00:03:43,121 --> 00:03:45,859
that's got like 16 ports or eight ports

82
00:03:45,859 --> 00:03:48,072
and it's like a little self-contained

83
00:03:48,072 --> 00:03:50,739
switch that's inside the router.

84
00:03:51,781 --> 00:03:53,393
And that's what this is right here.

85
00:03:53,393 --> 00:03:56,212
This EtherSwitch is actually a router

86
00:03:56,212 --> 00:03:58,386
that's got a switching
module inside of it.

87
00:03:58,386 --> 00:03:59,676
Why is that important?

88
00:03:59,676 --> 00:04:02,372
Because it doesn't really support all the

89
00:04:02,372 --> 00:04:04,546
commands that real switches do,

90
00:04:04,546 --> 00:04:06,841
that just something that
was built as a switch,

91
00:04:06,841 --> 00:04:08,654
it doesn't support all the commands.

92
00:04:08,654 --> 00:04:10,223
And some of the commands
that you would use

93
00:04:10,223 --> 00:04:12,682
for like configuring or showing things

94
00:04:12,682 --> 00:04:16,067
are a little bit different
than if I was on a real switch.

95
00:04:16,067 --> 00:04:19,289
So for example, review
question, what command

96
00:04:19,289 --> 00:04:23,456
would I type in a normal switch
to see what vlans I've got?

97
00:04:25,978 --> 00:04:28,153
Well, hopefully you said show vlan

98
00:04:28,153 --> 00:04:29,847
and you'd be absolutely right.

99
00:04:29,847 --> 00:04:31,580
But in this particular switch because it's

100
00:04:31,580 --> 00:04:36,015
really a router with a
switch module inside of it,

101
00:04:36,015 --> 00:04:37,866
the show vlan command doesn't work.

102
00:04:37,866 --> 00:04:40,003
That is a valid command on a real switch.

103
00:04:40,003 --> 00:04:42,017
And on the CCNA Exam,
that's what they would

104
00:04:42,017 --> 00:04:44,594
expect you to know, the show vlan command.

105
00:04:44,594 --> 00:04:48,261
But on this, it's
actually show vlan-switch.

106
00:04:53,131 --> 00:04:55,668
It's a little bit different.

107
00:04:55,668 --> 00:04:58,325
So you can see here,
here's my default vlan.

108
00:04:58,325 --> 00:05:01,265
And according to my
diagram, I'm on switch one

109
00:05:01,265 --> 00:05:04,903
so FastEthernet 1/1 should be in there.

110
00:05:04,903 --> 00:05:08,653
And it is and here's
vlan2 that I configured.

111
00:05:10,706 --> 00:05:14,319
And FastEthernet 1/2 is in that.

112
00:05:14,319 --> 00:05:18,269
And you can see right
here that is correct.

113
00:05:18,269 --> 00:05:21,531
Now what about 1/3 and 1/15?

114
00:05:21,531 --> 00:05:23,871
Both of these are
configured as vlan trunks

115
00:05:23,871 --> 00:05:26,452
so they are in multiple vlans.

116
00:05:26,452 --> 00:05:30,082
So let's just take a
look 1/15 as an example.

117
00:05:30,082 --> 00:05:33,103
If you look through
here, 1/15 doesn't show

118
00:05:33,103 --> 00:05:35,239
up anywhere in this output.

119
00:05:35,239 --> 00:05:39,629
It's not here because
this only shows you ports

120
00:05:39,629 --> 00:05:41,766
that are configured as access ports

121
00:05:41,766 --> 00:05:44,664
that are in one vlan and one vlan only.

122
00:05:44,664 --> 00:05:48,831
That's why 1/15 and
1/3 don't show up here.

123
00:05:49,704 --> 00:05:51,879
Because those interfaces are trunks.

124
00:05:51,879 --> 00:05:55,212
So to verify that, show interface trunk.

125
00:05:57,436 --> 00:06:00,579
And now you can verify, okay, 1/3.

126
00:06:00,579 --> 00:06:03,155
I used the switch port mode trunk command

127
00:06:03,155 --> 00:06:05,296
which forced the interface
to become a trunk.

128
00:06:05,296 --> 00:06:07,028
It didn't have a choice in the matter.

129
00:06:07,028 --> 00:06:09,725
That's why the same mode is on.

130
00:06:09,725 --> 00:06:11,901
And later on, we'll see
that there are other

131
00:06:11,901 --> 00:06:15,243
ways you can tell a port to
dynamically become a trunk

132
00:06:15,243 --> 00:06:18,101
if certain parameters are
exchanged between switches.

133
00:06:18,101 --> 00:06:20,276
But that's not what I did here.

134
00:06:20,276 --> 00:06:23,297
And you can see it's using
802.1q Encapsulation.

135
00:06:23,297 --> 00:06:25,547
And the Native vlan is one.

136
00:06:26,563 --> 00:06:29,825
Let's take a look at the configuration.

137
00:06:29,825 --> 00:06:32,767
How would I look at the
configuration of a router

138
00:06:32,767 --> 00:06:36,713
or a switch, what would be
the command I should type in?

139
00:06:36,713 --> 00:06:40,880
Show run or the long command
is show running-config.

140
00:06:46,423 --> 00:06:50,590
Just keep hitting my space
bar to get to the next level.

141
00:06:52,625 --> 00:06:55,970
And here we see, here's my first trunk.

142
00:06:55,970 --> 00:06:59,948
All I typed in was switchport mode trunk.

143
00:06:59,948 --> 00:07:01,759
As a matter of fact
this EtherSwitch module

144
00:07:01,759 --> 00:07:05,987
does support this switchport
trunk encapsulation.1q command.

145
00:07:05,987 --> 00:07:09,255
It let me type that in
but it defaulted to that.

146
00:07:09,255 --> 00:07:11,269
It doesn't even support
ISL so that's why we

147
00:07:11,269 --> 00:07:13,285
don't even see it here in the output.

148
00:07:13,285 --> 00:07:15,259
Swithport mode trunk is all I hate to do.

149
00:07:15,259 --> 00:07:19,005
And I had to make sure
that the interface was up.

150
00:07:19,005 --> 00:07:21,584
And I did no shut which
was also the default.

151
00:07:21,584 --> 00:07:22,751
That's why we don't see that here.

152
00:07:22,751 --> 00:07:24,969
And that's one thing about Cisco IOS.

153
00:07:24,969 --> 00:07:26,782
If you type in a command
that's already the

154
00:07:26,782 --> 00:07:29,764
default behavior most
of the time, you won't

155
00:07:29,764 --> 00:07:32,501
see it in the running config.

156
00:07:32,501 --> 00:07:33,991
Mostly what you see in the running config

157
00:07:33,991 --> 00:07:36,991
is non-default commands, not always.

158
00:07:38,702 --> 00:07:42,785
Okay, and so that's how
we configured the switch.

159
00:07:44,260 --> 00:07:46,476
If you are trunking to a router,

160
00:07:46,476 --> 00:07:47,361
it's a little bit different.

161
00:07:47,361 --> 00:07:49,860
Now the configuration on the
switch side is still the same.

162
00:07:49,860 --> 00:07:52,971
On FastEthernet 1/3, it's
switchport mode trunk.

163
00:07:52,971 --> 00:07:55,721
On 1/15, no different.

164
00:07:57,043 --> 00:07:58,898
Let me show you a little shortcut here.

165
00:07:58,898 --> 00:08:01,158
Instead of doing show run, I can say

166
00:08:01,158 --> 00:08:05,075
show run Interface FastEthernet 1/15

167
00:08:06,861 --> 00:08:09,761
and it only shows me that
portion of the configuration.

168
00:08:09,761 --> 00:08:11,330
Just that interface, I
don't have to scroll through

169
00:08:11,330 --> 00:08:14,276
everything so that's a
nice, little shortcut.

170
00:08:14,276 --> 00:08:18,140
So you can see, that's
configured exactly the same way.

171
00:08:18,140 --> 00:08:21,455
And the other side of the link,
the switch on the other side

172
00:08:21,455 --> 00:08:24,474
switch two, he's also configured that way.

173
00:08:24,474 --> 00:08:28,141
Now for router, it's a
little bit different.

174
00:08:29,308 --> 00:08:30,278
I'll just show you real quickly

175
00:08:30,278 --> 00:08:32,945
here the router's configuration.

176
00:08:36,277 --> 00:08:37,607
So in the router's configuration, I didn't

177
00:08:37,607 --> 00:08:41,753
really do anything on his main interface.

178
00:08:41,753 --> 00:08:42,922
Remember how I talked about, when we were

179
00:08:42,922 --> 00:08:46,911
talking about telnet and we
were talking about VTY lines,

180
00:08:46,911 --> 00:08:49,287
I said how on routers
and switches, sometimes

181
00:08:49,287 --> 00:08:52,352
they create these sort
of imaginary logical

182
00:08:52,352 --> 00:08:55,210
interfaces as like place
holders for things?

183
00:08:55,210 --> 00:08:56,540
We also talked about that when we did our

184
00:08:56,540 --> 00:09:00,043
switched virtual interface,
our interface vlan one

185
00:09:00,043 --> 00:09:03,223
in the last video, I believe.

186
00:09:03,223 --> 00:09:05,479
When we said, okay, where
do I put an IP address

187
00:09:05,479 --> 00:09:08,460
on a switch, oh interface vlan one.

188
00:09:08,460 --> 00:09:13,090
Well, here are a couple of
additional logical interfaces.

189
00:09:13,090 --> 00:09:15,427
These are called sub-interfaces,

190
00:09:15,427 --> 00:09:18,204
where you have some interface number

191
00:09:18,204 --> 00:09:21,909
and then a dot and then some other number.

192
00:09:21,909 --> 00:09:23,117
So I made these up from scratch.

193
00:09:23,117 --> 00:09:25,049
These did not exist before.

194
00:09:25,049 --> 00:09:27,063
And on a router, this
is how you take a router

195
00:09:27,063 --> 00:09:31,416
because if we look at
our topology diagram,

196
00:09:31,416 --> 00:09:33,416
where is it, right here.

197
00:09:35,080 --> 00:09:37,580
Just like this interface here,

198
00:09:38,946 --> 00:09:43,299
this interface here has to carry
multiple broadcast domains.

199
00:09:43,299 --> 00:09:48,252
Well, this link has to carry
multiple broadcast domains.

200
00:09:48,252 --> 00:09:51,958
Now, the switches, they don't
really care about layer three.

201
00:09:51,958 --> 00:09:54,293
All they care about is layer two.

202
00:09:54,293 --> 00:09:57,981
But the router, he does
care about layer three.

203
00:09:57,981 --> 00:10:00,505
He is a host, remember,
the router's interface

204
00:10:00,505 --> 00:10:03,848
is a host just like a
laptop is in a network.

205
00:10:03,848 --> 00:10:07,028
And he has to have an
IP address in a network.

206
00:10:07,028 --> 00:10:08,640
But here we have sort of
an interesting challenge

207
00:10:08,640 --> 00:10:12,383
because we actually
need this one interface

208
00:10:12,383 --> 00:10:16,550
to participate in two
networks, the 111 and the 222.

209
00:10:20,642 --> 00:10:24,387
And normally, an interface
can only be in one network.

210
00:10:24,387 --> 00:10:28,535
So how do we assign more than
one subnet to one interface?

211
00:10:28,535 --> 00:10:30,348
Well, what we can do is
we can trick the router.

212
00:10:30,348 --> 00:10:33,089
We can say, hey router, I
want you to make believe

213
00:10:33,089 --> 00:10:36,754
that you have more than
one interface here.

214
00:10:36,754 --> 00:10:39,754
And that is what sub-interfaces are.

215
00:10:41,264 --> 00:10:43,600
So by creating this
interface out of thin air,

216
00:10:43,600 --> 00:10:46,381
I've said, okay, on FastEthernet0/1,

217
00:10:46,381 --> 00:10:50,009
I'm actually gonna divide
you up into two interfaces.

218
00:10:50,009 --> 00:10:54,176
0/1.1 and 0/1.2, now the number after

219
00:10:56,895 --> 00:10:58,989
the dot could've been anything.

220
00:10:58,989 --> 00:11:03,156
I could've said 0/1.55 and 0/1.19.

221
00:11:04,794 --> 00:11:07,412
It's just the fact that
there's a dot followed by

222
00:11:07,412 --> 00:11:10,270
a number that tells the operating system,

223
00:11:10,270 --> 00:11:13,252
okay, this is a new, logical
interface that's being

224
00:11:13,252 --> 00:11:17,419
created and it's associated
with this physical interface.

225
00:11:19,615 --> 00:11:22,393
I just chose to use .1
because to me it made sense

226
00:11:22,393 --> 00:11:25,818
that this interface
would be used for vlan1

227
00:11:25,818 --> 00:11:29,651
and this .2 interface
would be used for vlan2.

228
00:11:30,489 --> 00:11:33,588
And then once I made my
sub-interfaces, the router didn't

229
00:11:33,588 --> 00:11:36,409
know what I wanted to do
with these sub-interfaces.

230
00:11:36,409 --> 00:11:38,949
It knew I was gonna put
different subnets on there,

231
00:11:38,949 --> 00:11:41,285
which I did with my IP addressing.

232
00:11:41,285 --> 00:11:44,988
But I had to tell the router,
hey, this sub-interface right

233
00:11:44,988 --> 00:11:49,155
here, you need to be able to
process tags, 802.1Q tags.

234
00:11:50,223 --> 00:11:52,680
And so when an Ethernet
frame comes in with

235
00:11:52,680 --> 00:11:56,506
an 802.1Q tag and the
vlan number inside there,

236
00:11:56,506 --> 00:11:59,166
it says vlan2, the router says, oh okay,

237
00:11:59,166 --> 00:12:02,711
this is a sub-interface
that's gonna deal with that.

238
00:12:02,711 --> 00:12:05,937
And when an Ethernet frame
comes in with no tag,

239
00:12:05,937 --> 00:12:08,354
which is on the native vlan,

240
00:12:08,354 --> 00:12:11,660
this sub-interface is
gonna deal with that.

241
00:12:11,660 --> 00:12:12,991
So you see this extra work,

242
00:12:12,991 --> 00:12:14,642
you don't have to do on switches.

243
00:12:14,642 --> 00:12:16,213
Switches automatically know, they know

244
00:12:16,213 --> 00:12:18,469
what vlans they've got
and they know whatever

245
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vlan you configured is gonna
be traveling across that trunk.

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But the router, he doesn't
know what vlans exist

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so I actually have to tell him with this

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encapsulation dot1Q command.

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So that being the case,
let's finish up here

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with taking a look at some of these tags.

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So let's start with, let's open

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up some sessions with my PCs.

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Okay, so PC1, I'm gonna have him ping PC3.

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Now PC3 here, show IP, so
in the context of GNS3,

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I'm using something called
the virtual PC simulator.

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VPCS and that's actually
something that's built into GNS3.

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It comes with it by default.

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And like it looks like,
it's a great little tool

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00:13:16,289 --> 00:13:20,881
for a simulated host here,
sorta like a virtual PC.

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So PC3 is, let's see here, 1.1.1.3

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and from PC1, I should
be able to ping that.

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Yup, I can ping it.

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Now, let's go ahead and
start a sniffer trace

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and the way I did this
in GNS3 is I just right

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clicked on the link and
I clicked Start capture.

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And yes, I wanna use
FastEthernet1/15 on EtherSwitch 1.

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Okay, so Wireshark is
starting up right here.

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Okay, there it goes, so
while it's doing its thing,

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let's do that ping again,
alright so there goes my ping.

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And PC4 is 2.2.2.3 so
I'll ping that from here.

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That ping was successful.

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00:14:17,679 --> 00:14:20,596
Okay, let's stop our sniffer trace.

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And in wire, you can
see here in Wireshark,

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I'm getting a lot of stuff.

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We haven't talked about spanning tree.

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Spanning tree is actually a protocol you

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00:14:27,947 --> 00:14:31,571
learn at the ICND2 level so I'm not

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gonna be talking about it
in this series of videos.

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But in Wireshark, if you
wanna filter something out,

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you say, okay, I wanna
filter all this garbage.

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00:14:38,899 --> 00:14:40,227
I don't want to see this.

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Just click on the frame and
in this particular case,

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I'll click on where it says Spanning Tree.

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I right click and then
as I right click I'll do

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Apply as Filter and I'll say Not.

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In other words, I don't wanna
see stuff that matches this.

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And it filters it out.

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Okay, so before we take
a look at that in depth.

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00:15:02,594 --> 00:15:05,511
So when vlan1, when PC1 pinged PC3,

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that was going across vlan1
and that's the native vlan,

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00:15:11,169 --> 00:15:13,103
by default so we should not see

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00:15:13,103 --> 00:15:15,686
any 802.1Q tags in those pings.

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00:15:17,494 --> 00:15:19,873
So here we go, I'll click on it.

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And you can see if I
expand the Ethernet header,

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00:15:24,467 --> 00:15:26,157
you can see it's a
regular Ethernet header.

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00:15:26,157 --> 00:15:29,787
You've got the Destination Mac, Source Mac

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00:15:29,787 --> 00:15:32,888
and then the Type Code and
this particular Type Code,

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it's carrying the number for IP version 4.

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00:15:35,424 --> 00:15:38,243
That is the reserve number for IPv4.

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00:15:38,243 --> 00:15:41,107
That probably is something
you should memorize.

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00:15:41,107 --> 00:15:43,121
That in an Ethernet frame, the Ether

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00:15:43,121 --> 00:15:46,538
type value or 0x0800 is for IP version 4.

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00:15:49,321 --> 00:15:51,671
So no mention here or any kind of a tag

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00:15:51,671 --> 00:15:54,855
which is what we would expect.

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00:15:54,855 --> 00:15:58,772
Now, if I go back, when
I ping from PC2 to PC4,

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that ping came in on vlan2
and so the switch said,

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00:16:03,554 --> 00:16:05,929
okay, in order for me to
put that across the trunk,

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00:16:05,929 --> 00:16:08,911
I have to apply an 802.1Q tag to that

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00:16:08,911 --> 00:16:12,737
indicating that this
frame belongs to vlan2.

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00:16:12,737 --> 00:16:15,112
And we will see that in here.

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00:16:15,112 --> 00:16:19,279
I'll just click on one of
those and there you can see it.

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00:16:20,347 --> 00:16:24,514
Ethernet two and look, the
Type Code is now 0x8100.

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00:16:26,349 --> 00:16:30,501
That is the reserved
value for an 802.1Q tag

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00:16:30,501 --> 00:16:32,074
and here is the tag right here.

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00:16:32,074 --> 00:16:35,536
If I open it up, you can see the fields.

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00:16:35,536 --> 00:16:38,194
There is a Priority field
if you want to do quality of

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00:16:38,194 --> 00:16:40,166
service, not something you really

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00:16:40,166 --> 00:16:42,823
learn about at the ICND1 level.

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00:16:42,823 --> 00:16:45,896
Canonical and Format Identifier,
don't worry about that.

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00:16:45,896 --> 00:16:48,192
No one's ever gonna ask
you what that field is.

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00:16:48,192 --> 00:16:52,359
And then here, you can see,
is our vlan identifier.

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00:16:53,309 --> 00:16:56,893
Vlan 2, it contains the number two.

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00:16:56,893 --> 00:17:00,726
So that concludes this
section on vlan trunks.

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(exciting music)