RARP (Assigning Internet address at start up)

RARP  (Assigning Internet address at start up)
RARP was once an essential protocol used to bootstrap system that did not have stable storage (i.e disk-less computer)

Operation field contain RARP req and RARP reply
Frame header contain frame type field to identify RARP type 803516

At start up
A system braodcast a RARP request to obtain IP address

• RARP+Ethernet address→request

All receives RARP request,only authorized supply RARP services process
RARP server look up ETHERNET address in its database if not contain extract the correspond IPV4 address from database ,once reply arrives the disk-less system continues to boot assigning its IPV4 address for communication
A network should contain at least one RARP server to respond

Primary and back up RARP server
Case 1

• Primary RARP server only respond no primary not respond 

Case 2

• Primary RARP server respond immediately non primary server respond delayed