The figure below explains the interactive procedure among Orbit nodes, CMC and Console/Service after commands like "omf load [1,2] baseline-7.11.ndz" is executed. This command will turn on a node and load specified Frisbee image to the hard driver of the node. The detail is explained below.

1. Node handler tells CMC to turn on the node through the CM.
2. The node boots from the Ethernet port by default and tried to acquire IP address from DHCP server.
3. DHCP and DNS server will assign IP address and corresponding host name for the node. DHCP also tells the node the address of Tftp server for PXE image.
4. Node handler makes a symbol link for the PXE configuration file. The symbol link named as the IP address of the node indicates the node to fetch the correct PXE image file.
5. The node downloads a small memory-based Linux kernel and file system from Tftp server.
6. The node boots up with the memory-based Linux kernel and launches Node Agent. Meanwhile, Node handler deletes the symbol link.
7. Node agent will inform Node handler after the initial boot up is done.
8. Node handler launches Frisbeed server with specified Frisbee image file and tells Node agent to run Frisbee client.
9. Frisbee client downloads a Frisbee image file and loads it to the hard driver.
10. After the imaging process is done, Node handler will turn off the node.

Some comments:

1. "omf" is the entry command for node handler.
   
2. CM is installed on the PCI slot of each node. It is a simple, reliable, platform-independent subsystem for managing and autonomously monitoring the status of each node in the ORBIT network test bed.
   
3. CMC is the only orbit service provided by Gridservice. Gridservice2 provides other orbit services.
   
4. Frisbee is a fast disk-imaging tool with server/client mode. More information can be found in ​http://www.emulab.net/downloads/frisbee-README-20031021.txt[[BR]]
5. Node agent and Node handler is used by Console to control orbit nodes to run programs or scripts on nodes.
   
6. Services includes a couple of generic services, such as DHCP, and Orbit-specified services, such as Frisbee and OML.