what is the difference between pinging a network and telnetting a network.

PING ([b]P[/b]acket [b]IN[/b]ternet [b]G[/b]roper):

This is a computer network tool used to test whether a particular host is reachable across an IP network.
It works by sending ICMP (Internet Control Message Protocol) "echo request" packets to the target host and listening for ICMP "echo response" replies. Ping estimates the round-trip time, generally in milliseconds, and records any packet loss, and prints a statistical summary when finished.

TELNET ([b]TEL[/b]communication [b]NET[/b]work):

This is a network protocol used on the Internet or local area network (LAN) connections for remotely accessing services on hosts. To achieve this, the host trying to access a remote host must have a "telnet client" running and the accessed host must have the "telnet server" running.

In basic terms, Ping is used primarily to test for network/host reachability while Telnet is used to create a session to a remote host: thus enabling access certain services as though you were physically located at the remote location.