Zone Allocation

Zone Allocation

There are two ways in which a domain tree can be divided into zones:
• By Class
• By “cuts”
These two methods, particularly allocation by “cuts”, serve to illustrate
further the difference between domains and zones.
Allocation by Class
To allocate zones by class is the simpler of the two methods. Each class
implemented within a domain is considered to be one zone, and will
contain the entirety of the domain tree, organized, delegated, and
maintained separately from all other classes.
Classes can be created for a domain, but as standard, there are only two
as defined by rfc 1034:
• IN This is the Internet class. It is the default class and used
throughout the Internet.

• CH This is the Chaos class. It is not widely used, originating as an
experimental class from the Massachusetts Institute of Technology.
Allocation by “Cuts”
This method of “cutting up” the domain space is perhaps the more
widely used within larger trees where there are too many hosts and
subdomains to be served by just one zone's name servers. The domain
tree is cut between adjacent nodes, e.g. between example and
development; the nodes or domains on one side belonging to a separate
domain to those nodes or domains on the other side.
• First zone - Contains the example.com domain, the advertising
subdomain and all its respective subdomains
• Second zone - Contains the development domain and all its
subdomains.
Each zone will have its own authoritative name server and secondary
name server.