Question : What are the differences between VLSM and CIDR? What do they mean in the context of IPv6?

Hi,

I've found this question: http://www.experts-exchange.com/Networking/Misc/Q_21400371.html

However, it still isn't clear to me what the differences are between VLSM and CIDR... Can somebody explain it as simple as possible (perhaps with an example). And explain what  they mean in the context of IPv6?

Thanks!

Answer : What are the differences between VLSM and CIDR? What do they mean in the context of IPv6?

Variable length subnet masking provides a mechanism for breaking up a network into smaller components. For example, 192.168.1.0/24 provides 1 network address and 254 host addresses. Using VLSM, I can create multiple networks out of the 192.168.1.0 network. For example, 192.168.1.0/25 represents 2 networks with 1 subnet bit: 192.168.1.0 and 192.168.1.128, each with 126 hosts.

Classless interdomain routing provides a mechanism for reprresenting lots of networks with only a single mask. For example if I use BGP to advertise 192.168.0.0/16, I am telling everyone who listens to by BGP announcement that I have the path to all the networks from 192.168.0.0 to 192.168.255.0.

As for how this plays out in IPv6, I'm not much of an IPv6 guy. I don't believe either of these schemes plays a part in IPv6 which has its own masking scheme.

Good luck,
SteveJ