Vlsm

wonder[riya7wonder[riya7 ■■□□□□□□□□ Posts: 41Banned ■■□□□□□□□□
In class he did variable length subnet masks. What is it and how does one do sums with it?

Comments

  • NissekiNisseki Posts: 160Member
    What resources are you using to study for your cisco?

    I'm using Todd Lammle's book and video series on IT Pro TV, he explains it quite well.
  • wonder[riya7wonder[riya7 ■■□□□□□□□□ Posts: 41Banned ■■□□□□□□□□
    I got the book. How long will it take to read the book?
  • Welly_59Welly_59 Posts: 431Member
    Less time if you actually started rather than asking
  • CryptoQueCryptoQue PMP, CISSP, CCNP, CCDP, CCNA, CCDA, CCENT, NET+, SEC+, ITILv3 VirginiaPosts: 205Member ■■■□□□□□□□
    wonder[riya7 VLSM is used to scale standard subnets (i.e. Class C) to fit network requirements. For example, if you're redesigning a network for a company that has 3 departments they want to keep isolated. Department 1 (HR) has 105 computers, department 2 (Finance) has 40 computers, and department 3 (Public Relations) has 55 computers. The company currently has all departments configured on a 192.168.1.0/24 network. You can use VLSM to meet the company's needs. You would breakdown the class C into smaller subnets that are comparable to the amount of hosts that will be connected.

    Network Subnet = 192.168.1.0/24
    HR = 105 computers = /25 = 126 usable IPs
    Finance = 40 computers = /26 = 62 usable IPs <---couldn't use a /27 because the maximum usable IPs for it is only 30
    Public Relations = 55 computers = 62 usable IPs

    New Networks
    HR = 192.168.1.0/25
    Finance = 192.168.1.128/26
    Public Relations = 192.168.1.192/26

    New IP Ranges
    HR = 192.168.1.1 - 192.168.1.126
    Finance = 192.168.1.129 - 192.168.1.190
    Public Relations = 192.168.1.193 - 192.168.1.254

    *routing will need to be involved in this process, but that's a more detailed topic you can find a lot of research on.
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