Real world VLSM application?

I watched the CBT Nuggets VLSM video and I get it...sort of.

Can anyone please tell what a real world application for VLSM would be, as described by Jeremy? In the video, he takes one 192.168.1.0 network and assigns it to multiple networks.

I don't recall how many, but at least three of these networks are on the inside interface of a router, meaning in all likelihood NAT would be used and you would not use an address from your block there. I get diving up the addresses for point to point links.

Is he just using this as an example to explain how VLSM works, or am I missing something here?

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dynamik

For all the same reasons as subnetting in general; this just gives you variable-sized networks.

For example, you want to create three vlans from a /24 network. One needs to support 100 hosts and the other two only need 50.

tech-airman

/usr wrote: »

I watched the CBT Nuggets VLSM video and I get it...sort of.

Can anyone please tell what a real world application for VLSM would be, as described by Jeremy? In the video, he takes one 192.168.1.0 network and assigns it to multiple networks.

I don't recall how many, but at least three of these networks are on the inside interface of a router, meaning in all likelihood NAT would be used and you would not use an address from your block there. I get diving up the addresses for point to point links.

Is he just using this as an example to explain how VLSM works, or am I missing something here?

/usr,

Within the scope of the CCNA level, understand that VLSM is a requirement and not optional within the scope of the routing protocol OSPF. That's because OSPF has no option at all, even with manual configuration, the option for automatic summarization like RIPv1. Effectively, you are variably subnetting the network when you configure any OSPF router in the form of effectively manually summarizing the VLSM boundaries into the various interface configurations on an OSPF router.

Does this help you understand and appreciate VLSM compared to Fixed Length Subnet Masking?