Enabling The Tcp Slow Start Algorithm; Setting The Ack Delay Timer - Cisco 4700M Configuration Manual

Chapter 4 Configuring TCP/IP Normalization and IP Reassembly Parameters

Enabling the TCP Slow Start Algorithm

Setting the ACK Delay Timer

OL-16202-01
Configuring a Connection Parameter Map for TCP/IP Normalization and Termination
The slow start algorithm is a congestion avoidance method in which TCP
increases its window size as ACK handshakes arrive. It operates by observing that
the rate at which new segments should be injected into the network is the rate at
which the acknowledgments are returned by the host at the other end of the
connection. This feature is disabled by default. For details about the TCP slow
start algorithm, see RFC 2581 and RFC 3782.
To enable the slow start algorithm, use the slowstart command in parameter map
connection configuration mode. The syntax of this command is as follows:
slowstart
For example, to enable the slow start feature, enter:
host1/C1(config-parammap-conn)# slowstart
To disable the slow start algorithm, enter:
host1/C1(config-parammap-conn)# no slowstart
You can configure the ACE to delay sending the ACK from a client to a server.
Some applications require delaying the ACK for best performance. Delaying the
ACK can also help reduce congestion by sending one ACK for multiple segments
rather than ACKing each segment individually. To configure an ACK delay, use
the set tcp ack-delay command in parameter map connection configuration
mode. The syntax of this command is as follows:
set ack-delay number
The number argument is an integer from 0 to 400 ms. The default is 200 ms.
For example, to delay sending an ACK from a client to a server for 400 ms, enter:
host1/C1(config-parammap-conn)# set ack-delay 400
To reset the ACK delay timer to the default value of 200 ms, enter:
host1/C1(config-parammap-conn)# no set ack-delay
Cisco 4700 Series Application Control Engine Appliance Security Configuration Guide
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