1.boot services

2. identification services

3.configuration services

4.installation services

These four services can be configured in different systems or in a single system

Boot services has the RARP and used to identify the client based on the ethernet address and provies the IP address to the client .

FILES:-/etc/ethers

           /etc/hosts

Identification services are used to provide the basic information like system time, local address, region etc

File:-rules.ok

configuration services are provide the information  about the disk partions and clusters to be installed 

File :-sysidcfg 

installation services provide the image to install in the client system.