This study guide is intended to provide those pursuing the CCNA certification with a framework of what concepts need to be studied. This is not a comprehensive document containing all the secrets of the CCNA, nor is it a “braindump” of questions and answers. I sincerely hope that this document provides some assistance and clarity in your studies.

1. How Update timer works ?
30
25
20
15
10
05
00
30
25
20
15
10
05
00
30
25
20
15
10
05
00
S0
HYD
30
25
20
15
10
05
00
S0
S1
CHE
10.0.0.0
E0
E0 - 192.168.1.0
1.150
S1
BAN
11.0.0.0
E0
E0 - 192.168.2.0
2.150
E0
E0 - 192.168.3.0
3.150
Network
Int
Hops
Network
Int
Hops
Network
Int
Hops
192.168.1.0
E0
0
192.168.2.0
E0
0
192.168.3.0
E0
0
10.0.0.0
S0
0
10.0.0.0
S1
0
11.0.0.0
S1
0
192.168.2.0
S0
1
11.0.0.0
S0
0
192.168.2.0
S1
1
11.0.0.0
S0
1
192.168.1.0
S1
1
10.0.0.0
S1
1
192.168.3.0
S0
2
LAN - 192.168.1.0/24
192.168.3.0
S0
1
LAN - 192.168.2.0/24
192.168.1.0
S1
2
LAN - 192.168.3.0/24
1

2. How Invalid timer works ?
180
150
120
90
60
30
00
180
150
120
90
60
30
00
S0
HYD
E0
E0 - 192.168.1.0
1.150
S0
S1
10.0.0.0
CHE
E0
E0 - 192.168.2.0
2.150
S1
11.0.0.0
BAN
E0
E0 - 192.168.3.0
3.150
Network
Int
Hops
Network
Int
Hops
Network
Int
Hops
192.168.1.0
E0
0
192.168.2.0
E0
0
192.168.3.0
E0
0
10.0.0.0
S0
0
10.0.0.0
S1
0
11.0.0.0
S1
0
192.168.2.0
S0
1
11.0.0.0
S0
0
192.168.2.0
S1
1
11.0.0.0
S0
1
192.168.1.0
S1
1
10.0.0.0
S1
1
192.168.3.0
S0
2
LAN - 192.168.1.0/24
192.168.3.0
S0
1
LAN - 192.168.2.0/24
192.168.1.0
S1
2
LAN - 192.168.3.0/24
2

3. How Invalid timer works ?
180
150
120
90
60
30
00
90
60
30
00
S0
HYD
E0
E0 - 192.168.1.0
1.150
S0
S1
10.0.0.0
CHE
E0
E0 - 192.168.2.0
2.150
S1
11.0.0.0
BAN
E0
E0 - 192.168.3.0
3.150
Network
Int
Hops
Network
Int
Hops
Network
Int
Hops
192.168.1.0
E0
0
192.168.2.0
E0
0
192.168.3.0
E0
0
10.0.0.0
S0
0
10.0.0.0
S1
0
11.0.0.0
S1
0
192.168.2.0
S0
1
11.0.0.0
S0
0
192.168.2.0
S1
1
11.0.0.0
S0
1
192.168.1.0
S1
1
10.0.0.0
S1
1
192.168.3.0
S0
2
LAN - 192.168.1.0/24
192.168.3.0
S0
1
LAN - 192.168.2.0/24
192.168.1.0
S1
2
LAN - 192.168.3.0/24
3

4. How Flush timer works ?
180
150
120
240
210
90
60
30
00
S0
HYD
E0
E0 - 192.168.1.0
1.150
S0
S1
10.0.0.0
CHE
E0
E0 - 192.168.2.0
2.150
S1
11.0.0.0
BAN
E0
E0 - 192.168.3.0
3.150
Network
Int
Hops
Network
Int
Hops
Network
Int
Hops
192.168.1.0
E0
0
192.168.2.0
E0
0
192.168.3.0
E0
0
10.0.0.0
S0
0
10.0.0.0
S1
0
11.0.0.0
S1
0
192.168.2.0
S0
1
11.0.0.0
S0
0
192.168.2.0
S1
1
11.0.0.0
S0
1
192.168.1.0
S1
1
10.0.0.0
S1
1
192.168.3.0
S0
2
LAN - 192.168.1.0/24
192.168.3.0
S0
1
LAN - 192.168.2.0/24
192.168.1.0
S1
2
LAN - 192.168.3.0/24
4