Smart Phone and Next Generation Mobile Computing

Mobile Application Challenges 453

default; however, in an interactive mobile IM session, the Nagle algo-

rithm may not perform well [14] if mobile devices are engaged in

high mobility. While the IM server is waiting for a pending ACK, for

immediate message delivery, the Nagle algorithm should be disabled

such that the IM server can continue to send text messages (thus

the number of outstanding segments is larger than one) and possibly

resend the original message, which will be reordered at the recipient.

However, disabling the Nagle algorithm (using the TCP_NODELAY

option) increases the number of small TCP segments, thereby reduc-

ing data delivery efficiency over precious wireless link bandwidth.

The solution is to have the IM application rather than ...