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Exam subnetting question

this is Exam question

can someone explain me what is correct answer for this

mant thanks

mahesh

3 ACCEPTED SOLUTIONS

Accepted Solutions

Re: Exam subnetting question

Link A just needs 2 IP's one for each router

Link A = 172.16.3.0/30

Usable 172.16.3.1 - 172.16.3.2

172.16.3.40/30 falls into the already used 172.16.3.32/27 network.

Network A needs 120 address, so the closest match here is a /25

Network A = 172.16.3.128/25

Usable 172.16.3.129 - 172.16.3.254

The other 2 /26 networks do not provide enough hosts as a /26 only gives 62 usable IP's.

Hall of Fame Super Gold

Re: Exam subnetting question

Mahesh

From this question network A has 120 hosts. A subnet with /26 mask will support only 62 hosts. So network A needs a /25 mask which will support 126 hosts. So "B" is one of the answers. For link A the correct answer is "D" because the choice in E overlaps the network for Marketing in the drawing.

HTH

Rick

Cisco Employee

Re: Exam subnetting question

Mahesh,

Network A requires at least a /25 to accommodate 120 hosts, which makes B the only option.

As far as link A is concerned, the answer could be D or E, but since D is contiguous with the 3 other links, I would say D is the logical one to pick.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
6 REPLIES

Re: Exam subnetting question

Link A just needs 2 IP's one for each router

Link A = 172.16.3.0/30

Usable 172.16.3.1 - 172.16.3.2

172.16.3.40/30 falls into the already used 172.16.3.32/27 network.

Network A needs 120 address, so the closest match here is a /25

Network A = 172.16.3.128/25

Usable 172.16.3.129 - 172.16.3.254

The other 2 /26 networks do not provide enough hosts as a /26 only gives 62 usable IP's.

Hall of Fame Super Gold

Re: Exam subnetting question

Mahesh

From this question network A has 120 hosts. A subnet with /26 mask will support only 62 hosts. So network A needs a /25 mask which will support 126 hosts. So "B" is one of the answers. For link A the correct answer is "D" because the choice in E overlaps the network for Marketing in the drawing.

HTH

Rick

Cisco Employee

Re: Exam subnetting question

Mahesh,

Network A requires at least a /25 to accommodate 120 hosts, which makes B the only option.

As far as link A is concerned, the answer could be D or E, but since D is contiguous with the 3 other links, I would say D is the logical one to pick.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Cisco Employee

Re: Exam subnetting question

Oops. Rick is correct. E is not an option. I check the network map too quickly.

Regards

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

Re: Exam subnetting question

Hi Harold

Does E not fall into the network range hanging off Marketing 172.16.3.32/27 :-s

New Member

Re: Exam subnetting question

hi

Many thanks to all again for solving my

questions

sincerely

mahesh

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