The SDM currently uses a routing file to determine the mapping between a hostname/port and 
an index. Each SDM server process obtains its index via an environment variable that is supplied
by the launcher (usually an MPI runtime system). The server then uses its index position to
determine its parent and connects to the hostname/port obtained from the routing file.

The format of the routing file is:

number_of_entries
index hostname port
...

where:

number_of_entries	- the number of mapping entries in the file (one less than the number
					  of lines in the file
index				- the index of this entry (0 .. N-1) where N is the number of servers
hostname 			- fully qualified host name or IP address of node
port 				- port number this server will be listening on