Shared Interface Usage Examples

See the following tables for examples of interface sharing and scalability. The below scenarios assume use of one physical/EtherChannel interface for management shared across all instances, and another physical or EtherChannel interface with dedicated subinterfaces for use with High Availability.

Firepower 9300 with Three SM-44s

The following table applies to three SM-44 security modules on a 9300 using only physical interfaces or EtherChannels. Without subinterfaces, the maximum number of interfaces are limited. Moreover, sharing multiple physical interfaces uses more forwarding table resources than sharing multiple subinterfaces.

Each SM-44 module can support up to 14 instances. Instances are split between modules as necessary to stay within limits.

Physical/EtherChannel Interfaces and Instances on a Firepower 9300 with Three SM-44s

Dedicated Interfaces

Shared Interfaces

Number of Instances

% Forwarding Table Used

32:

  • 8

  • 8

  • 8

  • 8

0

4:

  • Instance 1

  • Instance 2

  • Instance 3

  • Instance 4

16%

30:

  • 15

  • 15

0

2:

  • Instance 1

  • Instance 2

14%

14:

  • 14 (1 ea.)

1

14:

  • Instance 1-Instance 14

46%

33:

  • 11 (1 ea.)

  • 11 (1 ea.)

  • 11 (1 ea.)

3:

  • 1

  • 1

  • 1

33:

  • Instance 1-Instance 11

  • Instance 12-Instance 22

  • Instance 23-Instance 33

98%

33:

  • 11 (1 ea.)

  • 11 (1 ea.)

  • 12 (1 ea.)

3:

  • 1

  • 1

  • 1

34:

  • Instance 1-Instance 11

  • Instance 12-Instance 22

  • Instance 23-Instance 34

102%

DISALLOWED

30:

  • 30 (1 ea.)

1

6:

  • Instance 1-Instance 6

25%

30:

  • 10 (5 ea.)

  • 10 (5 ea.)

  • 10 (5 ea.)

3:

  • 1

  • 1

  • 1

6:

  • Instance 1-Instance2

  • Instance 2-Instance 4

  • Instance 5-Instance 6

23%

30:

  • 30 (6 ea.)

2

5:

  • Instance 1-Instance 5

28%

30:

  • 12 (6 ea.)

  • 18 (6 ea.)

4:

  • 2

  • 2

5:

  • Instance 1-Instance2

  • Instance 2-Instance 5

26%

24:

  • 6

  • 6

  • 6

  • 6

7

4:

  • Instance 1

  • Instance 2

  • Instance 3

  • Instance 4

44%

24:

  • 12 (6 ea.)

  • 12 (6 ea.)

14:

  • 7

  • 7

4:

  • Instance 1-Instance2

  • Instance 2-Instance 4

41%

The following table applies to three SM-44 security modules on a 9300 using subinterfaces on a single parent physical interface. For example, create a large EtherChannel to bundle all of your like-kind interfaces together, and then share subinterfaces of that EtherChannel. Sharing multiple physical interfaces uses more forwarding table resources than sharing multiple subinterfaces.

Each SM-44 module can support up to 14 instances. Instances are split between modules as necessary to stay within limits.

Subinterfaces on One Parent and Instances on a Firepower 9300 with Three SM-44s

Dedicated Subinterfaces

Shared Subinterfaces

Number of Instances

% Forwarding Table Used

168:

  • 168 (4 ea.)

0

42:

  • Instance 1-Instance 42

33%

224:

  • 224 (16 ea.)

0

14:

  • Instance 1-Instance 14

27%

14:

  • 14 (1 ea.)

1

14:

  • Instance 1-Instance 14

46%

33:

  • 11 (1 ea.)

  • 11 (1 ea.)

  • 11 (1 ea.)

3:

  • 1

  • 1

  • 1

33:

  • Instance 1-Instance 11

  • Instance 12-Instance 22

  • Instance 23-Instance 33

98%

70:

  • 70 (5 ea.)

1

14:

  • Instance 1-Instance 14

46%

165:

  • 55 (5 ea.)

  • 55 (5 ea.)

  • 55 (5 ea.)

3:

  • 1

  • 1

  • 1

33:

  • Instance 1-Instance 11

  • Instance 12-Instance 22

  • Instance 23-Instance 33

98%

70:

  • 70 (5 ea.)

2

14:

  • Instance 1-Instance 14

46%

165:

  • 55 (5 ea.)

  • 55 (5 ea.)

  • 55 (5 ea.)

6:

  • 2

  • 2

  • 2

33:

  • Instance 1-Instance 11

  • Instance 12-Instance 22

  • Instance 23-Instance 33

98%

70:

  • 70 (5 ea.)

10

14:

  • Instance 1-Instance 14

46%

165:

  • 55 (5 ea.)

  • 55 (5 ea.)

  • 55 (5 ea.)

30:

  • 10

  • 10

  • 10

33:

  • Instance 1-Instance 11

  • Instance 12-Instance 22

  • Instance 23-Instance 33

102%

DISALLOWED

Firepower 9300 with One SM-44

The following table applies to the Firepower 9300 with one SM-44 using only physical interfaces or EtherChannels. Without subinterfaces, the maximum number of interfaces are limited. Moreover, sharing multiple physical interfaces uses more forwarding table resources than sharing multiple subinterfaces.

The Firepower 9300 with one SM-44 can support up to 14 instances.

Physical/EtherChannel Interfaces and Instances on a Firepower 9300 with One SM-44

Dedicated Interfaces

Shared Interfaces

Number of Instances

% Forwarding Table Used

32:

  • 8

  • 8

  • 8

  • 8

0

4:

  • Instance 1

  • Instance 2

  • Instance 3

  • Instance 4

16%

30:

  • 15

  • 15

0

2:

  • Instance 1

  • Instance 2

14%

14:

  • 14 (1 ea.)

1

14:

  • Instance 1-Instance 14

46%

14:

  • 7 (1 ea.)

  • 7 (1 ea.)

2:

  • 1

  • 1

14:

  • Instance 1-Instance 7

  • Instance 8-Instance 14

37%

32:

  • 8

  • 8

  • 8

  • 8

1

4:

  • Instance 1

  • Instance 2

  • Instance 3

  • Instance 4

21%

32:

  • 16 (8 ea.)

  • 16 (8 ea.)

2

4:

  • Instance 1-Instance 2

  • Instance 3-Instance 4

20%

32:

  • 8

  • 8

  • 8

  • 8

2

4:

  • Instance 1

  • Instance 2

  • Instance 3

  • Instance 4

25%

32:

  • 16 (8 ea.)

  • 16 (8 ea.)

4:

  • 2

  • 2

4:

  • Instance 1-Instance 2

  • Instance 3-Instance 4

24%

24:

  • 8

  • 8

  • 8

8

3:

  • Instance 1

  • Instance 2

  • Instance 3

37%

10:

  • 10 (2 ea.)

10

5:

  • Instance 1-Instance 5

69%

10:

  • 6 (2 ea.)

  • 4 (2 ea.)

20:

  • 10

  • 10

5:

  • Instance 1-Instance 3

  • Instance 4-Instance 5

59%

14:

  • 12 (2 ea.)

10

7:

  • Instance 1-Instance 7

109%

DISALLOWED

The following table applies to the Firepower 9300 with one SM-44 using subinterfaces on a single parent physical interface. For example, create a large EtherChannel to bundle all of your like-kind interfaces together, and then share subinterfaces of that EtherChannel. Sharing multiple physical interfaces uses more forwarding table resources than sharing multiple subinterfaces.

The Firepower 9300 with one SM-44 can support up to 14 instances.

Subinterfaces on One Parent and Instances on a Firepower 9300 with One SM-44

Dedicated Subinterfaces

Shared Subinterfaces

Number of Instances

% Forwarding Table Used

112:

  • 112 (8 ea.)

0

14:

  • Instance 1-Instance 14

17%

224:

  • 224 (16 ea.)

0

14:

  • Instance 1-Instance 14

17%

14:

  • 14 (1 ea.)

1

14:

  • Instance 1-Instance 14

46%

14:

  • 7 (1 ea.)

  • 7 (1 ea.)

2:

  • 1

  • 1

14:

  • Instance 1-Instance 7

  • Instance 8-Instance 14

37%

112:

  • 112 (8 ea.)

1

14:

  • Instance 1-Instance 14

46%

112:

  • 56 (8 ea.)

  • 56 (8 ea.)

2:

  • 1

  • 1

14:

  • Instance 1-Instance 7

  • Instance 8-Instance 14

37%

112:

  • 112 (8 ea.)

2

14:

  • Instance 1-Instance 14

46%

112:

  • 56 (8 ea.)

  • 56 (8 ea.)

4:

  • 2

  • 2

14:

  • Instance 1-Instance 7

  • Instance 8-Instance 14

37%

140:

  • 140 (10 ea.)

10

14:

  • Instance 1-Instance 14

46%

140:

  • 70 (10 ea.)

  • 70 (10 ea.)

20:

  • 10

  • 10

14:

  • Instance 1-Instance 7

  • Instance 8-Instance 14

37%