TramasLLC

PRÁCTICA

1

Analizador de protocolo LLC
Redes de Computadoras • Escuela Superiór de Cómputo • Instituto Politécnico Nacional
En esta práctica se realizará una función que analice tramas del protocolo
LLC y se alimentara con las tramas capturadas por un programa que emplea
la librería winpcap.

Introducción
El protocolo LLC (control lógico de enlace) es un
protocolo de capa de enlace de datosderivado de
HDLC, del cual hereda su campo de control, y fue
estandarizado por la IEEE bajo la denominación
802.2. Igual que en HDLC se tienen tramas de
información, supervisión y no numeradas
distinguiéndose entre ellas por los bits menos
significativos de su campo de control.
Investigue el formato de las tramas LLC (802.2)
encapsuladas dentro del protocolo 802.3 y analice
las siguientes tramasllenando la tabla que se
encuentra al final de las mismas. En la tabla se
incluye el análisis de la primera trama para servir
de ejemplo.
1
00
7f
00
00
2
00
73
00
00
3
00
01
00
00
4
00
01
00
00
5
00
00
00
00
6
00
00
00
00
7
00
01
00
00
8
00
01
00

02
00
00
00

b3
00
00
00

9c
00
00
00

ae
00
00
00

ba
00
00
00

00
00
00
00

02
00
00
00

b3
00
00
00

9c
00
00
00

df
00
00
00

1b
00
00
00

00
00
00
4303
00
00
05

f0
00
00
90

f0
00
00
6d

02
00
00
00

b3
00
00
00

9c
00
00
00

df
00
00
00

1b
00
00
00

00
00
00
00

02
00
00
00

b3
00
00
00

9c
00
00
00

ae
00
00
00

ba
00
00
00

00
00
00
00

03
00
00
54

f0
00
00
90

f1
00
00
6d

02
01
00
00

b3
00
00
00

9c
00
00
00

ae
00
00
00

ba
00
00
00

00
00
00
00

02
00
00
00

b3
00
00
00

9c
00
00
00

df
00
00
00

1b
00
00
00

00
00
00
41

04
00
00a3

f0
00
00
90

f0
00
00
6d

02
01
00
00

b3
00
00
00

9c
00
00
00

df
00
00
00

1b
00
00
00

00
00
00
00

02
00
00
00

b3
00
00
00

9c
00
00
00

ae
00
00
00

ba
00
00
00

00
00
00
00

04
00
00
f2

f0
00
00
90

f1
00
00
6d

02
01
00
00

b3
0e
00
00

9c
00
00
00

ae
ff
00
00

ba
ef
00
00

00
19
00
00

02
8f
00
00

b3
bc
00
00

9c
05
00
00

df
7f
00
00

1b
00
00
00

00
23
00
00

12
00
00
41

f0
7f00
91

f0
23
00
6d

02
03
00
00

b3
0e
00
00

9c
00
00
00

df
ff
00
00

1b
ef
00
00

00
17
00
00

02
81
00
00

b3
bc
00
00

9c
05
00
00

ae
23
00
00

ba
00
00
00

00
7f
00
00

12
00
00
90

f0
23
00
91

f0
7f
00
6d

02
03
00
00

b3
00
00
00

9c
00
00
00

df
00
00
00

1b
00
00
00

00
00
00
00

02
00
00
00

b3
00
00
00

9c
00
00
00

ae
00
00
00

ba
00
00
00

00
00
00
00

04
00
00
df

f0
00
00
91

f100
00
6d

00
9
00
02
ff
00
00
52
4f
2e
32
00
72
54
10
00
01
00
00
11
00
02
ff
00
11
7f
2c
12
00
01
00
00
13
00
04
ff
00
0d
00
53
00
00
59
14
00
01
00
00
15
00
04
ff
00
03
49

00 00 00 00 00 00 00 00 00 00 00 18 ac 92 6d
02
02
53
00
77
4f
53
30
00
02
6b
20

b3
0e
4d
00
00
47
4f
00
02
57
67
4c

9c
00
42
00
02
52
46
02
44
69
72
4d

ae
ff
72
00
50
41
54
44
4f
6e
6f
20

ba
ef
00
00
43
4d
20
4f
53
64
7530

00
16
00
00
20
20
4e
53
20
6f
70
2e

02
04
00
00
4e
31
45
20
4c
77
73
31

b3
00
00
00
45
2e
54
4c
41
73
20
32

9c
00
00
00
54
30
57
4d
4e
20
33
00

df
00
00
00
57
00
4f
31
4d
66
2e
00

1b
00
00
00
4f
02
52
2e
41
6f
31
fb

00
28
00
00
52
4d
4b
32
4e
72
61
92

ac
00
00
00
4b
49
53
58
32
20
00
6d

f0
7f
00
82
20
43
20
30
2e
57
02
86

f0
23
00
09
50
52
33
30
31
6f
4e
df

02
04
00
00

b3
00
00
009c
00
00
00

df
00
00
00

1b
00
00
00

00
00
00
00

02
00
00
00

b3
00
00
00

9c
00
00
00

ae
00
00
00

ba
00
00
00

00
00
00
00

04
00
00
7b

f0
00
00
93

f1
00
00
6d

02
04
53
00
05
07
01

b3
0e
4d
00
00
00
08

9c
00
42
00
02
80
08

df
ff
72
00
02
03
00

1b
ef
00
00
00
02
7f

00
16
00
00
01
00
07

02
0c
00
00
00
00
00

b3
00
00
00
68
00
80

9c
00
80
00
0b
e5
32

ae
28
00
00
00
fe
3e

ba
00
0000
00
29
b9

00
28
00
00
00
25
3d

5f
00
00
00
00
7c
00

f0
23
00
82
01
c2
ca

f0
7f
00
09
00
01
93

02
04
00
00

b3
00
00
00

9c
00
00
00

ae
00
00
00

ba
00
00
00

00
00
00
00

02
00
00
00

b3
00
00
00

9c
00
00
00

df
00
00
00

1b
00
00
00

00
00
00
00

04
00
00
7c

f0
00
00
94

f1
00
00
6d

02
04
53
00
75
00
43
57
00
44

b3
0e
4d
00
00
00
4f
69
02
45

9c
00
42
00
5d
00
4d
6e
00
53

ae
ff
73...