Struggling with addressing table

aquarius121989

hi guys, I am struggling with this packer tracer skill integration.



I could find the IP address of PC1 and B1 Fa0/0 but I don't know how to find the B1 S0/0/0

The IP address of PC1 and B1 I got are
PC1: 192.168.1.126 255.255.255.128
B1: 192.168.1.1 255.255.255.128

using the first valid host for B1 and last valid host for PC1.
Can you guys help me to figure out the B1 S0/0/0

shortstop20

Well now that you have used the address space from 192.168.1.1 - 192.168.1.127, you simply need to move up to the next available addressing space.

If you were to use the network 192.168.1.128, what subnet mask would you need to use to ensure that it would not overlap with the other network while still providing 2 usable(4 total) IP addresses?

Find that, and you'll have your answer.

aquarius121989

but in the answer, B1 S0/0/0 is not 192.168.1.128, it suppose to be 192.168.1.225

shortstop20

Your first post wasn't very clear, made it sound like you didn't know what IP to apply to B1 S 0/0/0.

Since you know what IP is supposed to be you just need to assign the correct netmask. What netmask would you use for a link with only two hosts?

aquarius121989

here is the link to the challenge. The thing I don't get is the ip address of S0/0/0 and S0/0/1. How to get it?

Priston

On that picture you have 5 networks

B1 network - 80 hosts
B1 HQ point to point - 2 hosts
HQ network - 40 hosts
HQ B2 point to point - 2 hosts
B2 network - 20 hosts

You are given one /24, 192.168.1.0/24

You are going to use VLSM. When using VLSM I start with the biggest network and go to the smallest

B1 network - 80 hosts
We obviously can't use the whole /24
/25 has 126 hosts, 126 > 80. Yes a /25 will work
/26 has 62 hosts, 62 < 80. No this wont work, /25 it is!

B1 network is 192.168.1.0/25 (192.168.1.0-192.168.1.127)

Now lets move onto the next biggest subnet, HQ network - 40 hosts
Since we are given 192.168.1.0/24 and we used 192.168.1.0/25 we have 192.168.1.128/25 left for subnetting

/25 won't work because we need more networks
/26 has 62 hosts, 62 > 40. Yes, /26 will work
/27 has 30 hosts, 30 < 40. No this wont work, /26 it is!

HQ network is 192.168.1.128/26 (192.168.1.128-192.168.1.191)

Now lets move onto the next biggest subnet, B2 network - 20 hosts
Now that we've used 192.168.1.0/25 and 192.168.1.128/26 we have 192.168.1.192/26 left for subnetting

/26 won't work because we need more networks
/27 has 30 host, 30 > 20. Yes, 27 will work
/28 has 14 host, 14 < 20. No this wont work, /27 it is!

B2 network is 192.168.1.192/27 (192.168.1.192-223)

Next subnet, B1 HQ point to point - 2 hosts
Now that we've used 192.168.1.0/25, 192.168.128.0/26, and 192.168.1.192/27 we have 192.168.1.224/27 left for subnetting

/27 won't work because we need more networks
/28 has 14 host, 14 > 2. Yes a /25 will work.
/29 has 6 host, 6 > 2. Yes a /25 will work.
/30 has 2 host, 2 = 2. Lets use this!

B1 HQ point to point is 192.168.1.224/30 (192.168.1.224-192.168.1.227)

Next subnet, HQ B2 point to point - 2 hosts

... I'm sure you can figure out now

aquarius121989

Thank you so much Priston, you have saved my life.