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I'm studying for my CCNA exam and I have to create a VLSM scheme using RIP-2 for the following requirements: (this is an exercise)

  1. Use the class C network network for your point-to-point connections

  2. Using the Class A network, plan for the following number of hosts in each location: New York: 1000 Chicago: 500 Los Angeles: 1000

  3. On the LAN and point-to-point connections, select subnet masks that use the smallest ranges of IP addresses possible given the above requirements.

  4. In all cases, use the lowest possible subnet numbers. Subnet zero is allowed.

My guess is the following:

New York: S0/0 /24 Fa0/0 netmask - because we need 1000 hosts
Chicago: S0/0 /24 Fa0/0 netmask (for 500 hosts)
Los Angeles: S0/0 /24 Fa0/0 netmask (for 1000 hosts)

Is this a good configuration? I'm reading the CCNA book but not everything is very clear, so I said to do some exercises...

Thank you!

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for question 1, you using two class c networks and , these are on different subnets. As point to point links only contain 2 ip address, subnet zero and all 1's broadcasts, you can get and subnet it down , I'll let you figure out how many point to point links you can accommodate! – The Unix Janitor Apr 12 '10 at 15:23
I got the problem with point 1. I will have 3 subnets\24,\25 and\26 – Andrei T. Ursan Apr 12 '10 at 18:25
Cisco is still using the terminology of Class-based IP? Clas A/B/C/D? Really? That's sad... – Mark Henderson Apr 13 '10 at 2:17
up vote 1 down vote accepted

Here is my answer:
Set the following IP addresses to each it corresponding interface: /30

office network int to LA int to NY

office network int to CH int to LA

office network int to CH int to NY

next you have to set RIP-2 on each router for the and network and after disable the auto-summarization on each router.

share|improve this answer
Not explicitly stated, but it's usually address-conserving to start with the largest IP blocks, then allocate ranges for smaller and smaller blocks. That way, you don't end up with holes in the IP allocation. – Vatine Apr 13 '10 at 9:20

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