Nagle's algorithim is used for TCP-based applications to avoid send-side Silly Window Syndrome.
As far as Cisco router management is concerned, the service is used to optimize the Telnet or SSH session to the router by buffering the administrator's keystrokes and only sending a packet when a "sufficient" number of bytes are placed in the TCP segment. This avoids a situation in which each keystroke generates a TCP segment, which will generate 40 bytes of overhead for each character entered.
The purpose of enabling the Nagle service is to facilitate a remote management Telnet/SSH connection to a router in the event that the network is experiencing an inordinate amount of congestion or the router's CPU is bogged down as a result of a DOS attack.
OK, so what the heck is my question, right? Here goes...
If the Nagle service is meant to optimize the send-side/client connection for a TCP-based application, like Telnet or SSH, what does enabling Nagle on a router/switch do? Isn't the router or switch acting as the "server"/receiver in the session? Shouldn't the Nagle service be enabled on the administrator's computer or whatever device is being used as the "client"?