Network - Discontiguous
The term "discontiguous" is often used to describe a particular characteristic of networks. IPv4 addressing schemes, BGP Autonomous Systems, and OSPF areas can all have the characteristic of being discontigouous.
The term "discontiguous" typically refers to things that are not physically adjacent or not in direct contact with each other. For instance, in IP addressing, a discontiguous addressing scheme involves assigning two different networks that are numerically adjacent, but placing them physically far away from each other.
For example, the 10.1.1.0/24 and 10.1.2.0/24 networks are numerically adjacent, but in the diagram below, they are placed physically far away from each other.
These networks are said to be discontiguous because they are numerically but not physically adjacent.
This can create problems or must be dealt with in a particular way, especially when performing operations such as Summarization.
Other instances and features where discontiguity plays a role include:
- Discontiguous Autonomous Systems in BGP
- Discontiguous OSPF areas
- BGP AS Override feature
- BGP Allow-AS in
- BGP - auto-summary best practices
Concerning the terminology, take a look at Network - Discontiguous or Discontinuous for more information.
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