OPNET Technologies
7255 Woodmont Avenue
Bethesda, MD 20814
Tel: 240-497-3000
Fax: 240-497-3001
E-mail: university@opnet.com
Web: www.opnet.com

OPNET is a registered
trademark of OPNET Technologies
© 2002 OPNET Technologies

University: Dalhousie University
Professor: William J. Phillips
Department: Engineering Mathematics

We are using OPNET for:

Studying the performance of TCP over wireless networks

TCP is the most reliable, oriented connection that
is widely used. It is an end-to-end protocol that support flow and congestion
control. Due to the reliable wired networks, there is an assumption made
by TCP that any loss is due to congestion and consequently invokes congestion
control measures.

TCP faces a lot of problems in the wireless
network. Packet losses may occurs more often than in the wire line
packets. TCP interpret all the packet losses as notification of congestion
in the network. This will force the sender to take some corrective action
as activating the slow start algorithm and reducing the window
size.

We are using the OPNET modeler to study the
performance of the TCP over the wireless network. We will try to expand
the capability of TCP parameters in the OPNET by adding some function on
the TCP as Duplicate Selective Acknowledge. We are going to test this
parameter by drop some packets and reordering some. The result are
compared with other parameters as Selective acknowledgment.