I am trying to Explain both terms in some details with example, and trying to keep them as simple as I can so that you can easily understand the meaning of the terms and differences between them.Contiguous Network
The Synonyms of the word Contiguous is Continuous that means “connected together so as to form an unbroken sequence in time”.Now come to the Technical meaning of the Contiguous Network, is that Series of Classfull Subnets that lie under the same Major Classfull Network where the packets can pass between the Subnets crossing the subnet that also lies in the same Major Classfull Network.
Or Define in another Way
A classful network in which packets sent between every pair of subnets can pass only through subnets of that same classful network, without having to pass through subnets of any other classful network.
The Synonyms of the word Contiguous is Continuous that means “connected together so as to form an unbroken sequence in time”.Now come to the Technical meaning of the Contiguous Network, is that Series of Classfull Subnets that lie under the same Major Classfull Network where the packets can pass between the Subnets crossing the subnet that also lies in the same Major Classfull Network.
Or Define in another Way
A classful network in which packets sent between every pair of subnets can pass only through subnets of that same classful network, without having to pass through subnets of any other classful network.
Still Not got my Point, Ok lets have and Example of Contiguous Network with IP Subnet Addresses. Suppose you have a Classfull network with Subnets as follows,
192.168.0.0/24
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
See as I defined above this series of Classfull subnets can be summerized into a one classfull network 192.168.0.0/22
If it were non-contiguous (dis-contiguous) networks then you might have:
192.168.1.0/24
192.168.4.0/24
192.168.17.0/24
192.168.240.0/24
192.168.4.0/24
192.168.17.0/24
192.168.240.0/24
In this case you would not be able to summarize the networks without including other networks in the process. Using a network statement like 192.168.0.0/16 will include all of those networks but crucially it also includes all networks from 192.168.0.0 to 192.168.255.0.
So from above example we can define Discontiguous Network as A classfull network in which packets sent between at least one pair of subnets must pass through subnets of a different classfull network
